using System;
using System.Collections;
using UnityEngine.Events;
using UnityEngine.EventSystems;
using UnityEngine.Serialization;
#if UNITY_EDITOR
using UnityEditor;
#endif

namespace UnityEngine.UI
{
    /// <summary>
    /// Turn a simple label into a interactable input field.
    /// </summary>

    [AddComponentMenu("UI/Input Field", 31)]
    public class InputField
        : Selectable,
        IUpdateSelectedHandler,
        IBeginDragHandler,
        IDragHandler,
        IEndDragHandler,
        IPointerClickHandler,
        ISubmitHandler,
        ICanvasElement,
        ILayoutElement
    {
        /// <summary>
        /// Setting the content type acts as a shortcut for setting a combination of InputType, CharacterValidation, LineType, and TouchScreenKeyboardType
        /// </summary>
        /// <remarks>
        /// The ContentType affects character validation, keyboard type used (on platforms with on-screen keyboards), whether the InputField accepts multiple lines, and whether the text is autocorrected (on platforms that offer input auto-correction) or is treated as a password where the characters are not shown directly.
        /// </remarks>
        public enum ContentType
        {
            /// <summary>
            /// Allows all input.
            /// </summary>
            Standard,

            /// <summary>
            /// Allows all input and performs auto-correction on platforms that support it.
            /// </summary>
            Autocorrected,
            /// <summary>
            /// Allow whole numbers (positive or negative).
            /// </summary>
            IntegerNumber,

            /// <summary>
            /// Allows decimal numbers (positive or negative).
            /// </summary>
            DecimalNumber,

            /// <summary>
            /// Allows letters A-Z, a-z and numbers 0-9.
            /// </summary>
            Alphanumeric,

            /// <summary>
            /// The InputField is used for typing in a name, and enforces capitalization of the first letter of each word. Note that the user can circumvent the first letter capitalization rules by deleting automatically-capitalized letters.
            /// </summary>
            Name,

            /// <summary>
            /// The input is used for typing in an email address.
            /// </summary>
            EmailAddress,

            /// <summary>
            /// Allows all input and hides the typed characters by showing them as asterisks characters.
            /// </summary>
            Password,

            /// <summary>
            /// Allows integer numbers and hides the typed characters by showing them as asterisks characters.
            /// </summary>
            Pin,

            /// <summary>
            /// Custom types that allows user-defined settings.
            /// </summary>
            Custom
        }

        /// <summary>
        /// Type of data expected by the input field mobile keyboard.
        /// </summary>
        public enum InputType
        {
            /// <summary>
            /// The standard mobile keyboard
            /// </summary>
            Standard,

            /// <summary>
            /// The mobile autocorrect keyboard.
            /// </summary>
            AutoCorrect,

            /// <summary>
            /// The mobile password keyboard.
            /// </summary>
            Password,
        }

        /// <summary>
        /// The type of characters that are allowed to be added to the string.
        /// </summary>
        /// <remarks>
        /// Note that the character validation does not validate the entire string as being valid or not. It only does validation on a per-character level, resulting in the typed character either being added to the string or not
        /// </remarks>
        public enum CharacterValidation
        {
            /// <summary>
            /// No validation. Any input is valid.
            /// </summary>
            None,

            /// <summary>
            /// Allow whole numbers (positive or negative).
            /// Characters 0-9 and - (dash / minus sign) are allowed. The dash is only allowed as the first character.
            /// </summary>
            Integer,
            /// <summary>
            /// Allows decimal numbers (positive or negative).
            /// </summary>
            /// <remarks>
            /// Characters 0-9, . (dot), and - (dash / minus sign) are allowed. The dash is only allowed as the first character. Only one dot in the string is allowed.
            /// </remarks>
            Decimal,

            /// <summary>
            /// Allows letters A-Z, a-z and numbers 0-9.
            /// </summary>
            Alphanumeric,

            /// <summary>
            /// Only allow names and enforces capitalization.
            /// </summary>
            /// <remarks>
            /// Allows letters, spaces, and ' (apostrophe). A character after a space is automatically made upper case. A character not after a space is automatically made lowercase. A character after an apostrophe can be either upper or lower case. Only one apostrophe in the string is allowed. More than one space in a row is not allowed.
            ///
            /// A characters is considered a letter if it is categorized as a Unicode letter, as implemented by the Char.Isletter method in .Net.
            /// </remarks>
            Name,

            /// <summary>
            /// Allows the characters that are allowed in an email address.
            /// </summary>
            /// <remarks>
            /// Allows characters A-Z, a.z, 0-9, @, . (dot), !, #, $, %, &amp;, ', *, +, -, /, =, ?, ^, _, `, {, |, }, and ~.
            ///
            /// Only one @ is allowed in the string and more than one dot in a row are not allowed. Note that the character validation does not validate the entire string as being a valid email address since it only does validation on a per-character level, resulting in the typed character either being added to the string or not.
            /// </remarks>
            EmailAddress
        }

        /// <summary>
        /// The LineType is used to describe the behavior of the InputField.
        /// </summary>
        public enum LineType
        {
            /// <summary>
            /// Only allows 1 line to be entered. Has horizontal scrolling and no word wrap. Pressing enter will submit the InputField.
            /// </summary>
            SingleLine,

            /// <summary>
            /// Is a multiline InputField with vertical scrolling and overflow. Pressing the return key will submit.
            /// </summary>
            MultiLineSubmit,

            /// <summary>
            /// Is a multiline InputField with vertical scrolling and overflow. Pressing the return key will insert a new line character.
            /// </summary>
            MultiLineNewline
        }

        public delegate char OnValidateInput(string text, int charIndex, char addedChar);

        [Serializable]
        /// <summary>
        ///   Unity Event with a inputfield as a param.
        /// </summary>
        public class SubmitEvent : UnityEvent<string> {}

        [Serializable]
        /// <summary>
        /// The callback sent anytime the Inputfield is updated.
        /// </summary>
        public class OnChangeEvent : UnityEvent<string> {}

        protected TouchScreenKeyboard m_Keyboard;
        static private readonly char[] kSeparators = { ' ', '.', ',', '\t', '\r', '\n' };

        /// <summary>
        /// Text Text used to display the input's value.
        /// </summary>

        [SerializeField]
        [FormerlySerializedAs("text")]
        protected Text m_TextComponent;

        [SerializeField]
        protected Graphic m_Placeholder;

        [SerializeField]
        private ContentType m_ContentType = ContentType.Standard;

        [FormerlySerializedAs("inputType")]
        [SerializeField]
        private InputType m_InputType = InputType.Standard;

        [FormerlySerializedAs("asteriskChar")]
        [SerializeField]
        private char m_AsteriskChar = '*';

        [FormerlySerializedAs("keyboardType")]
        [SerializeField]
        private TouchScreenKeyboardType m_KeyboardType = TouchScreenKeyboardType.Default;

        [SerializeField]
        private LineType m_LineType = LineType.SingleLine;

        [FormerlySerializedAs("hideMobileInput")]
        [SerializeField]
        private bool m_HideMobileInput = false;

        [FormerlySerializedAs("validation")]
        [SerializeField]
        private CharacterValidation m_CharacterValidation = CharacterValidation.None;

        [FormerlySerializedAs("characterLimit")]
        [SerializeField]
        private int m_CharacterLimit = 0;

        [FormerlySerializedAs("onSubmit")]
        [FormerlySerializedAs("m_OnSubmit")]
        [FormerlySerializedAs("m_EndEdit")]
        [SerializeField]
        private SubmitEvent m_OnEndEdit = new SubmitEvent();

        [FormerlySerializedAs("onValueChange")]
        [FormerlySerializedAs("m_OnValueChange")]
        [SerializeField]
        private OnChangeEvent m_OnValueChanged = new OnChangeEvent();

        [FormerlySerializedAs("onValidateInput")]
        [SerializeField]
        private OnValidateInput m_OnValidateInput;

        [FormerlySerializedAs("selectionColor")]
        [SerializeField]
        private Color m_CaretColor = new Color(50f / 255f, 50f / 255f, 50f / 255f, 1f);

        [SerializeField]
        private bool m_CustomCaretColor = false;

        [SerializeField]
        private Color m_SelectionColor = new Color(168f / 255f, 206f / 255f, 255f / 255f, 192f / 255f);

        [SerializeField]
        [FormerlySerializedAs("mValue")]
        protected string m_Text = string.Empty;

        [SerializeField]
        [Range(0f, 4f)]
        private float m_CaretBlinkRate = 0.85f;

        [SerializeField]
        [Range(1, 5)]
        private int m_CaretWidth = 1;

        [SerializeField]
        private bool m_ReadOnly = false;

        [SerializeField]
        private bool m_ShouldActivateOnSelect = true;

        protected int m_CaretPosition = 0;
        protected int m_CaretSelectPosition = 0;
        private RectTransform caretRectTrans = null;
        protected UIVertex[] m_CursorVerts = null;
        private TextGenerator m_InputTextCache;
        private CanvasRenderer m_CachedInputRenderer;
        private bool m_PreventFontCallback = false;
        [NonSerialized] protected Mesh m_Mesh;
        private bool m_AllowInput = false;
        private bool m_ShouldActivateNextUpdate = false;
        private bool m_UpdateDrag = false;
        private bool m_DragPositionOutOfBounds = false;
        private const float kHScrollSpeed = 0.05f;
        private const float kVScrollSpeed = 0.10f;
        protected bool m_CaretVisible;
        private Coroutine m_BlinkCoroutine = null;
        private float m_BlinkStartTime = 0.0f;
        protected int m_DrawStart = 0;
        protected int m_DrawEnd = 0;
        private Coroutine m_DragCoroutine = null;
        private string m_OriginalText = "";
        private bool m_WasCanceled = false;
        private bool m_HasDoneFocusTransition = false;
        private WaitForSecondsRealtime m_WaitForSecondsRealtime;
        private bool m_TouchKeyboardAllowsInPlaceEditing = false;

        private BaseInput input
        {
            get
            {
                if (EventSystem.current && EventSystem.current.currentInputModule)
                    return EventSystem.current.currentInputModule.input;
                return null;
            }
        }

        private string compositionString
        {
            get { return input != null ? input.compositionString : Input.compositionString; }
        }

        // Doesn't include dot and @ on purpose! See usage for details.
        const string kEmailSpecialCharacters = "!#$%&'*+-/=?^_`{|}~";

        protected InputField()
        {
            EnforceTextHOverflow();
        }

        protected Mesh mesh
        {
            get
            {
                if (m_Mesh == null)
                    m_Mesh = new Mesh();
                return m_Mesh;
            }
        }

        protected TextGenerator cachedInputTextGenerator
        {
            get
            {
                if (m_InputTextCache == null)
                    m_InputTextCache = new TextGenerator();

                return m_InputTextCache;
            }
        }

        /// <summary>
        /// Should the mobile keyboard input be hidden. This allows for input to happen with a caret in the InputField instead of a OS input box above the keyboard.
        /// </summary>
        /// <example>
        /// <code>
        /// using UnityEngine;
        /// using System.Collections;
        /// using UnityEngine.UI; // Required when Using UI elements.
        ///
        /// public class Example : MonoBehaviour
        /// {
        ///     public InputField mainInputField;
        ///
        ///     public void Start()
        ///     {
        ///         //This setting can be toggled in the inspector.
        ///         mainInputField.shouldHideMobileInput = true;
        ///     }
        /// }
        /// </code>
        /// </example>
        public bool shouldHideMobileInput
        {
            set
            {
                SetPropertyUtility.SetStruct(ref m_HideMobileInput, value);
            }
            get
            {
                switch (Application.platform)
                {
                    case RuntimePlatform.Android:
                    case RuntimePlatform.IPhonePlayer:
                    case RuntimePlatform.tvOS:
                        return m_HideMobileInput;
                }

                return true;
            }
        }

        /// <summary>
        /// Should the inputfield be automatically activated upon selection.
        /// </summary>

        public virtual bool shouldActivateOnSelect
        {
            set
            {
                m_ShouldActivateOnSelect = value;
            }
            get
            {
                return m_ShouldActivateOnSelect && Application.platform != RuntimePlatform.tvOS;
            }
        }

        /// <summary>
        /// Input field's current text value. This is not necessarily the same as what is visible on screen.
        /// </summary>
        /// <remarks>
        /// Note that null is invalid value  for InputField.text.
        /// </remarks>
        /// <example>
        /// <code>
        /// using UnityEngine;
        /// using System.Collections;
        /// using UnityEngine.UI; // Required when Using UI elements.
        ///
        /// public class Example : MonoBehaviour
        /// {
        ///     public InputField mainInputField;
        ///
        ///     public void Start()
        ///     {
        ///         mainInputField.text = "Enter Text Here...";
        ///     }
        /// }
        /// </code>
        /// </example>
        public string text
        {
            get
            {
                return m_Text;
            }
            set
            {
                SetText(value);
            }
        }

        /// <summary>
        /// Set the current text value of the Input field without invoking onValueChanged.
        /// </summary>
        /// <remarks>
        /// This is not necessarily the same as what is visible on screen.
        /// </remarks>
        public void SetTextWithoutNotify(string input)
        {
            SetText(input, false);
        }

        void SetText(string value, bool sendCallback = true)
        {
            if (this.text == value)
                return;
            if (value == null)
                value = "";
            value = value.Replace("\0", string.Empty); // remove embedded nulls
            if (m_LineType == LineType.SingleLine)
                value = value.Replace("\n", "").Replace("\t", "");

            // If we have an input validator, validate the input and apply the character limit at the same time.
            if (onValidateInput != null || characterValidation != CharacterValidation.None)
            {
                m_Text = "";
                OnValidateInput validatorMethod = onValidateInput ?? Validate;
                m_CaretPosition = m_CaretSelectPosition = value.Length;
                int charactersToCheck = characterLimit > 0 ? Math.Min(characterLimit, value.Length) : value.Length;
                for (int i = 0; i < charactersToCheck; ++i)
                {
                    char c = validatorMethod(m_Text, m_Text.Length, value[i]);
                    if (c != 0)
                        m_Text += c;
                }
            }
            else
            {
                m_Text = characterLimit > 0 && value.Length > characterLimit ? value.Substring(0, characterLimit) : value;
            }

#if UNITY_EDITOR
            if (!Application.isPlaying)
            {
                SendOnValueChangedAndUpdateLabel();
                return;
            }
#endif

            if (m_Keyboard != null)
                m_Keyboard.text = m_Text;

            if (m_CaretPosition > m_Text.Length)
                m_CaretPosition = m_CaretSelectPosition = m_Text.Length;
            else if (m_CaretSelectPosition > m_Text.Length)
                m_CaretSelectPosition = m_Text.Length;

            if (sendCallback)
                SendOnValueChanged();
            UpdateLabel();
        }

        /// <summary>
        /// Whether the InputField has focus and whether it is able to process events.
        /// </summary>
        /// <example>
        /// <code>
        /// using UnityEngine;
        /// using System.Collections;
        /// using UnityEngine.UI; // Required when Using UI elements.
        ///
        /// public class Example : MonoBehaviour
        /// {
        ///     public GameObject mainInputField;
        ///
        ///     void Update()
        ///     {
        ///         //If the input field is focused, change its color to green.
        ///         if (mainInputField.GetComponent<InputField>().isFocused == true)
        ///         {
        ///             mainInputField.GetComponent<Image>().color = Color.green;
        ///         }
        ///     }
        /// }
        /// </code>
        /// </example>
        public bool isFocused
        {
            get { return m_AllowInput; }
        }

        /// <summary>
        /// The blinking rate of the input caret, defined as the number of times the blink cycle occurs per second.
        /// </summary>
        public float caretBlinkRate
        {
            get { return m_CaretBlinkRate; }
            set
            {
                if (SetPropertyUtility.SetStruct(ref m_CaretBlinkRate, value))
                {
                    if (m_AllowInput)
                        SetCaretActive();
                }
            }
        }

        /// <summary>
        /// The width of the caret in pixels.
        /// </summary>
        public int caretWidth { get { return m_CaretWidth; } set { if (SetPropertyUtility.SetStruct(ref m_CaretWidth, value)) MarkGeometryAsDirty(); } }

        /// <summary>
        /// The Text component that is going to be used to render the text to screen.
        /// </summary>
        public Text textComponent
        {
            get { return m_TextComponent; }
            set
            {
                if (m_TextComponent != null)
                {
                    m_TextComponent.UnregisterDirtyVerticesCallback(MarkGeometryAsDirty);
                    m_TextComponent.UnregisterDirtyVerticesCallback(UpdateLabel);
                    m_TextComponent.UnregisterDirtyMaterialCallback(UpdateCaretMaterial);
                }

                if (SetPropertyUtility.SetClass(ref m_TextComponent, value))
                {
                    EnforceTextHOverflow();
                    if (m_TextComponent != null)
                    {
                        m_TextComponent.RegisterDirtyVerticesCallback(MarkGeometryAsDirty);
                        m_TextComponent.RegisterDirtyVerticesCallback(UpdateLabel);
                        m_TextComponent.RegisterDirtyMaterialCallback(UpdateCaretMaterial);
                    }
                }
            }
        }

        /// <summary>
        /// This is an optional ‘empty’ graphic to show that the InputField text field is empty. Note that this ‘empty' graphic still displays even when the InputField is selected (that is; when there is focus on it).
        /// A placeholder graphic can be used to show subtle hints or make it more obvious that the control is an InputField.
        /// </summary>
        /// <remarks>
        /// If a Text component is used as the placeholder, it's recommended to make the placeholder text look different from the real text of the InputField so they are not easily confused. For example, the placeholder text might be a more subtle color or have lower alpha value.
        /// </remarks>
        public Graphic placeholder { get { return m_Placeholder; } set { SetPropertyUtility.SetClass(ref m_Placeholder, value); } }

        /// <summary>
        /// The custom caret color used if customCaretColor is set.
        /// </summary>
        public Color caretColor { get { return customCaretColor ? m_CaretColor : textComponent.color; } set { if (SetPropertyUtility.SetColor(ref m_CaretColor, value)) MarkGeometryAsDirty(); } }

        /// <summary>
        /// Should a custom caret color be used or should the textComponent.color be used.
        /// </summary>
        public bool customCaretColor { get { return m_CustomCaretColor; } set { if (m_CustomCaretColor != value) { m_CustomCaretColor = value; MarkGeometryAsDirty(); } } }

        /// <summary>
        /// The color of the highlight to show which characters are selected.
        /// </summary>
        /// <example>
        /// <code>
        /// using UnityEngine;
        /// using System.Collections;
        /// using UnityEngine.UI; // Required when Using UI elements.
        ///
        /// public class Example : MonoBehaviour
        /// {
        ///     public InputField mainInputField;
        ///
        ///     // Changes the color of the highlight that shows what characters are selected.
        ///     void ChangeSelectionColor()
        ///     {
        ///         mainInputField.selectionColor = Color.red;
        ///     }
        /// }
        /// </code>
        /// </example>
        public Color selectionColor { get { return m_SelectionColor; } set { if (SetPropertyUtility.SetColor(ref m_SelectionColor, value)) MarkGeometryAsDirty(); } }

        /// <summary>
        /// The Unity Event to call when editing has ended
        /// </summary>
        /// <example>
        /// <code>
        /// using UnityEngine;
        /// using System.Collections;
        /// using UnityEngine.UI; // Required when Using UI elements.
        ///
        /// public class Example : MonoBehaviour
        /// {
        ///     public InputField mainInputField;
        ///
        ///     // Checks if there is anything entered into the input field.
        ///     void LockInput(InputField input)
        ///     {
        ///         if (input.text.Length > 0)
        ///         {
        ///             Debug.Log("Text has been entered");
        ///         }
        ///         else if (input.text.Length == 0)
        ///         {
        ///             Debug.Log("Main Input Empty");
        ///         }
        ///     }
        ///
        ///     public void Start()
        ///     {
        ///         //Adds a listener that invokes the "LockInput" method when the player finishes editing the main input field.
        ///         //Passes the main input field into the method when "LockInput" is invoked
        ///         mainInputField.onEndEdit.AddListener(delegate {LockInput(mainInputField); });
        ///     }
        /// }
        /// </code>
        /// </example>
        public SubmitEvent onEndEdit { get { return m_OnEndEdit; } set { SetPropertyUtility.SetClass(ref m_OnEndEdit, value); } }

        [Obsolete("onValueChange has been renamed to onValueChanged")]
        public OnChangeEvent onValueChange { get { return onValueChanged; } set { onValueChanged = value; } }

        /// <summary>
        /// Accessor to the OnChangeEvent.
        /// </summary>
        /// <example>
        /// <code>
        /// using UnityEngine;
        /// using System.Collections;
        /// using UnityEngine.UI; // Required when Using UI elements.
        ///
        /// public class Example : MonoBehaviour
        /// {
        ///     public InputField mainInputField;
        ///
        ///     public void Start()
        ///     {
        ///         //Adds a listener to the main input field and invokes a method when the value changes.
        ///         mainInputField.onValueChange.AddListener(delegate {ValueChangeCheck(); });
        ///     }
        ///
        ///     // Invoked when the value of the text field changes.
        ///     public void ValueChangeCheck()
        ///     {
        ///         Debug.Log("Value Changed");
        ///     }
        /// }
        /// </code>
        /// </example>
        public OnChangeEvent onValueChanged { get { return m_OnValueChanged; } set { SetPropertyUtility.SetClass(ref m_OnValueChanged, value); } }

        /// <summary>
        /// The function to call to validate the input characters.
        /// </summary>
        /// <example>
        /// <code>
        /// using UnityEngine;
        /// using System.Collections;
        /// using UnityEngine.UI; // Required when Using UI elements.
        ///
        /// public class Example : MonoBehaviour
        /// {
        ///     public InputField mainInputField;
        ///
        ///     public void Start()
        ///     {
        ///         // Sets the MyValidate method to invoke after the input field's default input validation invoke (default validation happens every time a character is entered into the text field.)
        ///         mainInputField.onValidateInput += delegate(string input, int charIndex, char addedChar) { return MyValidate(addedChar); };
        ///     }
        ///
        ///     private char MyValidate(char charToValidate)
        ///     {
        ///         //Checks if a dollar sign is entered....
        ///         if (charToValidate == '$')
        ///         {
        ///             // ... if it is change it to an empty character.
        ///             charToValidate = '\0';
        ///         }
        ///         return charToValidate;
        ///     }
        /// }
        /// </code>
        /// </example>
        public OnValidateInput onValidateInput { get { return m_OnValidateInput; } set { SetPropertyUtility.SetClass(ref m_OnValidateInput, value); } }

        /// <summary>
        /// How many characters the input field is limited to. 0 = infinite.
        /// </summary>
        /// <example>
        /// <code>
        /// using UnityEngine;
        /// using System.Collections;
        /// using UnityEngine.UI; // Required when Using UI elements.
        ///
        /// public class Example : MonoBehaviour
        /// {
        ///     public InputField mainInputField;
        ///     public string playerName;
        ///
        ///     void Start()
        ///     {
        ///         //Changes the character limit in the main input field.
        ///         mainInputField.characterLimit = playerName.Length;
        ///     }
        /// }
        /// </code>
        /// </example>
        public int characterLimit
        {
            get { return m_CharacterLimit; }
            set
            {
                if (SetPropertyUtility.SetStruct(ref m_CharacterLimit, Math.Max(0, value)))
                {
                    UpdateLabel();
                    if (m_Keyboard != null)
                        m_Keyboard.characterLimit = value;
                }
            }
        }

        /// <summary>
        /// Specifies the type of the input text content.
        /// </summary>
        /// <remarks>
        /// The ContentType affects character validation, keyboard type used (on platforms with on-screen keyboards), whether the InputField accepts multiple lines, and whether the text is autocorrected (on platforms that offer input auto-correction) or is treated as a password where the characters are not shown directly.
        /// </remarks>
        /// <example>
        /// <code>
        /// using UnityEngine;
        /// using System.Collections;
        /// using UnityEngine.UI; // Required when Using UI elements.
        ///
        /// public class Example : MonoBehaviour
        /// {
        ///     public InputField mainInputField;
        ///     public string playerName;
        ///
        ///     void Start()
        ///     {
        ///         //Changes the character limit in the main input field.
        ///         mainInputField.characterLimit = playerName.Length;
        ///     }
        /// }
        /// </code>
        /// </example>
        public ContentType contentType { get { return m_ContentType; } set { if (SetPropertyUtility.SetStruct(ref m_ContentType, value)) EnforceContentType(); } }

        /// <summary>
        /// The LineType used by the InputField.
        /// </summary>
        /// <example>
        /// <code>
        /// using UnityEngine;
        /// using System.Collections;
        /// using UnityEngine.UI; // Required when Using UI elements.
        ///
        /// public class Example : MonoBehaviour
        /// {
        ///     public GameObject mainInputField;
        ///
        ///     //When you press a button, this method is called.
        ///     public void ChangeInputField(int type)
        ///     {
        ///         if (type == 0)
        ///         {
        ///             //Change the input field to "Single Line" line type.
        ///             mainInputField.GetComponent<InputField>().lineType = InputField.LineType.SingleLine;
        ///         }
        ///         else if (type == 1)
        ///         {
        ///             //Change the input field to "MultiLine Newline" line type.
        ///             mainInputField.GetComponent<InputField>().lineType = InputField.LineType.MultiLineNewline;
        ///         }
        ///         else if (type == 2)
        ///         {
        ///             //Change the input field to "MultiLine Submit" line type.
        ///             mainInputField.GetComponent<InputField>().lineType = InputField.LineType.MultiLineSubmit;
        ///         }
        ///     }
        /// }
        /// </code>
        /// </example>
        public LineType lineType
        {
            get { return m_LineType; }
            set
            {
                if (SetPropertyUtility.SetStruct(ref m_LineType, value))
                {
                    SetToCustomIfContentTypeIsNot(ContentType.Standard, ContentType.Autocorrected);
                    EnforceTextHOverflow();
                }
            }
        }

        /// <summary>
        /// The type of input expected. See InputField.InputType.
        /// </summary>
        public InputType inputType { get { return m_InputType; } set { if (SetPropertyUtility.SetStruct(ref m_InputType, value)) SetToCustom(); } }

        /// <summary>
        /// The TouchScreenKeyboard being used to edit the Input Field.
        /// </summary>
        public TouchScreenKeyboard touchScreenKeyboard { get { return m_Keyboard; } }

        /// <summary>
        /// They type of mobile keyboard that will be used.
        /// </summary>
        public TouchScreenKeyboardType keyboardType
        {
            get { return m_KeyboardType; }
            set
            {
                if (SetPropertyUtility.SetStruct(ref m_KeyboardType, value))
                    SetToCustom();
            }
        }

        /// <summary>
        /// The type of validation to perform on a character
        /// </summary>
        public CharacterValidation characterValidation { get { return m_CharacterValidation; } set { if (SetPropertyUtility.SetStruct(ref m_CharacterValidation, value)) SetToCustom(); } }

        /// <summary>
        /// Set the InputField to be read only.
        /// </summary>
        /// <remarks>
        /// Setting read only allows for highlighting of text without allowing modifications via keyboard.
        /// </remarks>
        public bool readOnly { get { return m_ReadOnly; } set { m_ReadOnly = value; } }

        /// <summary>
        /// If the input field supports multiple lines.
        /// </summary>
        /// <example>
        /// <code>
        /// using UnityEngine;
        /// using System.Collections;
        /// using UnityEngine.UI; // Required when Using UI elements.
        ///
        /// public class Example : MonoBehaviour
        /// {
        ///     public InputField mainInputField;
        ///
        ///     public void Update()
        ///     {
        ///         //Check to see if the input field is set to allow multiple lines.
        ///         if (mainInputField.multiLine)
        ///         {
        ///             //Set the input field to only allow Single Lines, if it is currently set to allow Multiple lines.
        ///             mainInputField.lineType = InputField.LineType.SingleLine;
        ///             //Print to console
        ///             Debug.Log("The main input field is now set to allow single lines only!");
        ///         }
        ///     }
        /// }
        /// </code>
        /// </example>
        public bool multiLine { get { return m_LineType == LineType.MultiLineNewline || lineType == LineType.MultiLineSubmit; } }

        /// <summary>
        /// The character used to hide text in password field.
        /// </summary>
        /// <remarks>
        /// Not shown in the inspector.
        /// </remarks>
        /// <example>
        /// <code>
        /// using UnityEngine;
        /// using System.Collections;
        /// using UnityEngine.UI; // Required when Using UI elements.
        ///
        /// public class Example : MonoBehaviour
        /// {
        ///     public InputField mainInputField;
        ///
        ///     void Start()
        ///     {
        ///         // changes the password symbol. 0 = $, 1 = ! 2 = £ and so on.
        ///         mainInputField.asteriskChar = "$!£%&*"[0];
        ///     }
        /// }
        /// </code>
        /// </example>
        public char asteriskChar { get { return m_AsteriskChar; } set { if (SetPropertyUtility.SetStruct(ref m_AsteriskChar, value)) UpdateLabel(); } }

        /// <summary>
        /// If the InputField was canceled and will revert back to the original text upon DeactivateInputField.
        /// </summary>
        public bool wasCanceled { get { return m_WasCanceled; } }

        /// <summary>
        /// Clamp a value (by reference) between 0 and the current text length.
        /// </summary>
        /// <param name="pos">The input position to be clampped</param>
        protected void ClampPos(ref int pos)
        {
            if (pos < 0) pos = 0;
            else if (pos > text.Length) pos = text.Length;
        }

        /// <summary>
        /// Current position of the cursor.
        /// Getters are public Setters are protected
        /// </summary>

        protected int caretPositionInternal { get { return m_CaretPosition + compositionString.Length; } set { m_CaretPosition = value; ClampPos(ref m_CaretPosition); } }
        protected int caretSelectPositionInternal { get { return m_CaretSelectPosition + compositionString.Length; } set { m_CaretSelectPosition = value; ClampPos(ref m_CaretSelectPosition); } }
        private bool hasSelection { get { return caretPositionInternal != caretSelectPositionInternal; } }

#if UNITY_EDITOR
        [System.ComponentModel.EditorBrowsable(System.ComponentModel.EditorBrowsableState.Never)]
        [Obsolete("caretSelectPosition has been deprecated. Use selectionFocusPosition instead (UnityUpgradable) -> selectionFocusPosition", true)]
        public int caretSelectPosition { get { return selectionFocusPosition; } protected set { selectionFocusPosition = value; } }
#endif

        /// <summary>
        /// Get: Returns the focus position as thats the position that moves around even during selection.
        /// Set: Set both the anchor and focus position such that a selection doesn't happen
        /// </summary>

        public int caretPosition
        {
            get { return m_CaretSelectPosition + compositionString.Length; }
            set { selectionAnchorPosition = value; selectionFocusPosition = value; }
        }

        /// <summary>
        /// The beginning point of the selection.
        /// </summary>
        /// <remarks>
        /// When making a selection with a mouse, the anchor is where in the document the mouse button is initially pressed.
        /// Get: Returns the beginning position of selection
        /// Set: If Input.compositionString is 0 set the fixed position.
        /// </remarks>
        public int selectionAnchorPosition
        {
            get { return m_CaretPosition + compositionString.Length; }
            set
            {
                if (compositionString.Length != 0)
                    return;

                m_CaretPosition = value;
                ClampPos(ref m_CaretPosition);
            }
        }

        /// <summary>
        /// The end point of the selection.
        /// </summary>
        /// <remarks>
        /// When making a selection with a mouse, the focus is where in the document the mouse button is released.
        /// Get: Returns the end position of selection
        /// Set: If Input.compositionString is 0 set the variable position.
        /// </remarks>
        public int selectionFocusPosition
        {
            get { return m_CaretSelectPosition + compositionString.Length; }
            set
            {
                if (compositionString.Length != 0)
                    return;

                m_CaretSelectPosition = value;
                ClampPos(ref m_CaretSelectPosition);
            }
        }

    #if UNITY_EDITOR
        // Remember: This is NOT related to text validation!
        // This is Unity's own OnValidate method which is invoked when changing values in the Inspector.
        protected override void OnValidate()
        {
            base.OnValidate();
            EnforceContentType();
            EnforceTextHOverflow();

            m_CharacterLimit = Math.Max(0, m_CharacterLimit);

            //This can be invoked before OnEnabled is called. So we shouldn't be accessing other objects, before OnEnable is called.
            if (!IsActive())
                return;

            // fix case 1040277
            ClampPos(ref m_CaretPosition);
            ClampPos(ref m_CaretSelectPosition);


            UpdateLabel();
            if (m_AllowInput)
                SetCaretActive();
        }

    #endif // if UNITY_EDITOR

        protected override void OnEnable()
        {
            base.OnEnable();
            if (m_Text == null)
                m_Text = string.Empty;
            m_DrawStart = 0;
            m_DrawEnd = m_Text.Length;

            // If we have a cached renderer then we had OnDisable called so just restore the material.
            if (m_CachedInputRenderer != null)
                m_CachedInputRenderer.SetMaterial(m_TextComponent.GetModifiedMaterial(Graphic.defaultGraphicMaterial), Texture2D.whiteTexture);

            if (m_TextComponent != null)
            {
                m_TextComponent.RegisterDirtyVerticesCallback(MarkGeometryAsDirty);
                m_TextComponent.RegisterDirtyVerticesCallback(UpdateLabel);
                m_TextComponent.RegisterDirtyMaterialCallback(UpdateCaretMaterial);
                UpdateLabel();
            }
        }

        protected override void OnDisable()
        {
            // the coroutine will be terminated, so this will ensure it restarts when we are next activated
            m_BlinkCoroutine = null;

            DeactivateInputField();
            if (m_TextComponent != null)
            {
                m_TextComponent.UnregisterDirtyVerticesCallback(MarkGeometryAsDirty);
                m_TextComponent.UnregisterDirtyVerticesCallback(UpdateLabel);
                m_TextComponent.UnregisterDirtyMaterialCallback(UpdateCaretMaterial);
            }
            CanvasUpdateRegistry.UnRegisterCanvasElementForRebuild(this);

            // Clear needs to be called otherwise sync never happens as the object is disabled.
            if (m_CachedInputRenderer != null)
                m_CachedInputRenderer.Clear();

            if (m_Mesh != null)
                DestroyImmediate(m_Mesh);
            m_Mesh = null;

            base.OnDisable();
        }

        IEnumerator CaretBlink()
        {
            // Always ensure caret is initially visible since it can otherwise be confusing for a moment.
            m_CaretVisible = true;
            yield return null;

            while (isFocused && m_CaretBlinkRate > 0)
            {
                // the blink rate is expressed as a frequency
                float blinkPeriod = 1f / m_CaretBlinkRate;

                // the caret should be ON if we are in the first half of the blink period
                bool blinkState = (Time.unscaledTime - m_BlinkStartTime) % blinkPeriod < blinkPeriod / 2;
                if (m_CaretVisible != blinkState)
                {
                    m_CaretVisible = blinkState;
                    if (!hasSelection)
                        MarkGeometryAsDirty();
                }

                // Then wait again.
                yield return null;
            }
            m_BlinkCoroutine = null;
        }

        void SetCaretVisible()
        {
            if (!m_AllowInput)
                return;

            m_CaretVisible = true;
            m_BlinkStartTime = Time.unscaledTime;
            SetCaretActive();
        }

        // SetCaretActive will not set the caret immediately visible - it will wait for the next time to blink.
        // However, it will handle things correctly if the blink speed changed from zero to non-zero or non-zero to zero.
        void SetCaretActive()
        {
            if (!m_AllowInput)
                return;

            if (m_CaretBlinkRate > 0.0f)
            {
                if (m_BlinkCoroutine == null)
                    m_BlinkCoroutine = StartCoroutine(CaretBlink());
            }
            else
            {
                m_CaretVisible = true;
            }
        }

        private void UpdateCaretMaterial()
        {
            if (m_TextComponent != null && m_CachedInputRenderer != null)
                m_CachedInputRenderer.SetMaterial(m_TextComponent.GetModifiedMaterial(Graphic.defaultGraphicMaterial), Texture2D.whiteTexture);
        }

        /// <summary>
        /// Focus the input field initializing properties.
        /// </summary>
        /// <remarks>
        /// Handles what happens after a user selects an InputField. This is a protected property. To return the focus state use InputField.isFocused. To shift focus to another GameObject, use EventSystem.SetSelectedGameObject.
        /// A common use of this is allowing the user to type once focussed. Another way is outputting a message when the user clicks on a field(often seen when creating passwords).
        /// </remarks>
        /// <example>
        /// //Create an Input Field by going to __Create__>__UI__>__Input Field__. Attach this script to the Input Field GameObject
        /// <code>
        /// using UnityEngine;
        /// using UnityEngine.UI;
        ///
        /// public class Example : MonoBehaviour
        /// {
        ///     InputField m_InputField;
        ///     void Start()
        ///     {
        ///         //Fetch the Input Field component from the GameObject
        ///         m_InputField = GetComponent<InputField>();
        ///     }
        ///
        ///     void Update()
        ///     {
        ///         //Check if the Input Field is in focus and able to alter
        ///         if (m_InputField.isFocused)
        ///         {
        ///             //Change the Color of the Input Field's Image to green
        ///             m_InputField.GetComponent<Image>().color = Color.green;
        ///         }
        ///     }
        /// }
        /// </code>
        /// </example>
        protected void OnFocus()
        {
            SelectAll();
        }

        /// <summary>
        /// Highlight the whole InputField.
        /// </summary>
        /// <remarks>
        /// Sets the caretPosition to the length of the text and caretSelectPos to 0.
        /// </remarks>
        protected void SelectAll()
        {
            caretPositionInternal = text.Length;
            caretSelectPositionInternal = 0;
        }

        /// <summary>
        /// Move the caret index to end of text.
        /// </summary>
        /// <param name="shift">Only move the selection position to facilate selection</param>
        public void MoveTextEnd(bool shift)
        {
            int position = text.Length;

            if (shift)
            {
                caretSelectPositionInternal = position;
            }
            else
            {
                caretPositionInternal = position;
                caretSelectPositionInternal = caretPositionInternal;
            }
            UpdateLabel();
        }

        /// <summary>
        /// Move the caret index to start of text.
        /// </summary>
        /// <param name="shift">Only move the selection position to facilate selection</param>
        public void MoveTextStart(bool shift)
        {
            int position = 0;

            if (shift)
            {
                caretSelectPositionInternal = position;
            }
            else
            {
                caretPositionInternal = position;
                caretSelectPositionInternal = caretPositionInternal;
            }

            UpdateLabel();
        }

        static string clipboard
        {
            get
            {
                return GUIUtility.systemCopyBuffer;
            }
            set
            {
                GUIUtility.systemCopyBuffer = value;
            }
        }

        // Returns true if the TouchScreenKeyboard should be used. On Android and Chrome OS, we only want to use the
        // TouchScreenKeyboard if in-place editing is not allowed (i.e. when we do not have a hardware keyboard available).
        private bool TouchScreenKeyboardShouldBeUsed()
        {
            RuntimePlatform platform = Application.platform;
            switch (platform)
            {
                case RuntimePlatform.Android:
                    return !TouchScreenKeyboard.isInPlaceEditingAllowed;
                default:
                    return TouchScreenKeyboard.isSupported;
            }
        }

        private bool InPlaceEditing()
        {
            return !TouchScreenKeyboard.isSupported || m_TouchKeyboardAllowsInPlaceEditing;
        }

        // In-place editing can change state if a hardware keyboard becomes available or is hidden while the input field is activated.
        // This currently only happens on Chrome OS devices (that support laptop and tablet mode).
        private bool InPlaceEditingChanged()
        {
            return m_TouchKeyboardAllowsInPlaceEditing != TouchScreenKeyboard.isInPlaceEditingAllowed;
        }

        void UpdateCaretFromKeyboard()
        {
            var selectionRange = m_Keyboard.selection;

            var selectionStart = selectionRange.start;
            var selectionEnd = selectionRange.end;

            var caretChanged = false;

            if (caretPositionInternal != selectionStart)
            {
                caretChanged = true;
                caretPositionInternal = selectionStart;
            }

            if (caretSelectPositionInternal != selectionEnd)
            {
                caretSelectPositionInternal = selectionEnd;
                caretChanged = true;
            }

            if (caretChanged)
            {
                m_BlinkStartTime = Time.unscaledTime;

                UpdateLabel();
            }
        }

        /// <summary>
        /// Update the text based on input.
        /// </summary>
        // TODO: Make LateUpdate a coroutine instead. Allows us to control the update to only be when the field is active.
        protected virtual void LateUpdate()
        {
            // Only activate if we are not already activated.
            if (m_ShouldActivateNextUpdate)
            {
                if (!isFocused)
                {
                    ActivateInputFieldInternal();
                    m_ShouldActivateNextUpdate = false;
                    return;
                }

                // Reset as we are already activated.
                m_ShouldActivateNextUpdate = false;
            }

            AssignPositioningIfNeeded();

            // If the device's state changed in a way that affects whether we should use a touchscreen keyboard or not,
            // then we make sure to clear all of the caret/highlight state visually and deactivate the input field.
            if (isFocused && InPlaceEditingChanged())
            {
                if (m_CachedInputRenderer != null)
                {
                    using (var helper = new VertexHelper())
                        helper.FillMesh(mesh);

                    m_CachedInputRenderer.SetMesh(mesh);
                }

                DeactivateInputField();
            }

            if (!isFocused || InPlaceEditing())
                return;

            if (m_Keyboard == null || m_Keyboard.status != TouchScreenKeyboard.Status.Visible)
            {
                if (m_Keyboard != null)
                {
                    if (!m_ReadOnly)
                        text = m_Keyboard.text;

                    if (m_Keyboard.status == TouchScreenKeyboard.Status.Canceled)
                        m_WasCanceled = true;
                }

                OnDeselect(null);
                return;
            }

            string val = m_Keyboard.text;

            if (m_Text != val)
            {
                if (m_ReadOnly)
                {
                    m_Keyboard.text = m_Text;
                }
                else
                {
                    m_Text = "";

                    for (int i = 0; i < val.Length; ++i)
                    {
                        char c = val[i];

                        if (c == '\r' || (int)c == 3)
                            c = '\n';

                        if (onValidateInput != null)
                            c = onValidateInput(m_Text, m_Text.Length, c);
                        else if (characterValidation != CharacterValidation.None)
                            c = Validate(m_Text, m_Text.Length, c);

                        if (lineType == LineType.MultiLineSubmit && c == '\n')
                        {
                            m_Keyboard.text = m_Text;

                            OnDeselect(null);
                            return;
                        }

                        if (c != 0)
                            m_Text += c;
                    }

                    if (characterLimit > 0 && m_Text.Length > characterLimit)
                        m_Text = m_Text.Substring(0, characterLimit);

                    if (m_Keyboard.canGetSelection)
                    {
                        UpdateCaretFromKeyboard();
                    }
                    else
                    {
                        caretPositionInternal = caretSelectPositionInternal = m_Text.Length;
                    }

                    // Set keyboard text before updating label, as we might have changed it with validation
                    // and update label will take the old value from keyboard if we don't change it here
                    if (m_Text != val)
                        m_Keyboard.text = m_Text;

                    SendOnValueChangedAndUpdateLabel();
                }
            }
            else if (m_HideMobileInput && m_Keyboard.canSetSelection)
            {
                var selectionStart = Mathf.Min(caretSelectPositionInternal, caretPositionInternal);
                var selectionLength = Mathf.Abs(caretSelectPositionInternal - caretPositionInternal);
                m_Keyboard.selection = new RangeInt(selectionStart, selectionLength);
            }
            else if (m_Keyboard.canGetSelection && !m_HideMobileInput)
            {
                UpdateCaretFromKeyboard();
            }


            if (m_Keyboard.status != TouchScreenKeyboard.Status.Visible)
            {
                if (m_Keyboard.status == TouchScreenKeyboard.Status.Canceled)
                    m_WasCanceled = true;

                OnDeselect(null);
            }
        }

        [Obsolete("This function is no longer used. Please use RectTransformUtility.ScreenPointToLocalPointInRectangle() instead.")]
        public Vector2 ScreenToLocal(Vector2 screen)
        {
            var theCanvas = m_TextComponent.canvas;
            if (theCanvas == null)
                return screen;

            Vector3 pos = Vector3.zero;
            if (theCanvas.renderMode == RenderMode.ScreenSpaceOverlay)
            {
                pos = m_TextComponent.transform.InverseTransformPoint(screen);
            }
            else if (theCanvas.worldCamera != null)
            {
                Ray mouseRay = theCanvas.worldCamera.ScreenPointToRay(screen);
                float dist;
                Plane plane = new Plane(m_TextComponent.transform.forward, m_TextComponent.transform.position);
                plane.Raycast(mouseRay, out dist);
                pos = m_TextComponent.transform.InverseTransformPoint(mouseRay.GetPoint(dist));
            }
            return new Vector2(pos.x, pos.y);
        }

        private int GetUnclampedCharacterLineFromPosition(Vector2 pos, TextGenerator generator)
        {
            if (!multiLine)
                return 0;

            // transform y to local scale
            float y = pos.y * m_TextComponent.pixelsPerUnit;
            float lastBottomY = 0.0f;

            for (int i = 0; i < generator.lineCount; ++i)
            {
                float topY = generator.lines[i].topY;
                float bottomY = topY - generator.lines[i].height;

                // pos is somewhere in the leading above this line
                if (y > topY)
                {
                    // determine which line we're closer to
                    float leading = topY - lastBottomY;
                    if (y > topY - 0.5f * leading)
                        return i - 1;
                    else
                        return i;
                }

                if (y > bottomY)
                    return i;

                lastBottomY = bottomY;
            }

            // Position is after last line.
            return generator.lineCount;
        }

        /// <summary>
        /// Given an input position in local space on the Text return the index for the selection cursor at this position.
        /// </summary>
        /// <param name="pos">Mouse position.</param>
        /// <returns>Character index with in value.</returns>
        protected int GetCharacterIndexFromPosition(Vector2 pos)
        {
            TextGenerator gen = m_TextComponent.cachedTextGenerator;

            if (gen.lineCount == 0)
                return 0;

            int line = GetUnclampedCharacterLineFromPosition(pos, gen);
            if (line < 0)
                return 0;
            if (line >= gen.lineCount)
                return gen.characterCountVisible;

            int startCharIndex = gen.lines[line].startCharIdx;
            int endCharIndex = GetLineEndPosition(gen, line);

            for (int i = startCharIndex; i < endCharIndex; i++)
            {
                if (i >= gen.characterCountVisible)
                    break;

                UICharInfo charInfo = gen.characters[i];
                Vector2 charPos = charInfo.cursorPos / m_TextComponent.pixelsPerUnit;

                float distToCharStart = pos.x - charPos.x;
                float distToCharEnd = charPos.x + (charInfo.charWidth / m_TextComponent.pixelsPerUnit) - pos.x;
                if (distToCharStart < distToCharEnd)
                    return i;
            }

            return endCharIndex;
        }

        private bool MayDrag(PointerEventData eventData)
        {
            return IsActive() &&
                IsInteractable() &&
                eventData.button == PointerEventData.InputButton.Left &&
                m_TextComponent != null &&
                (InPlaceEditing() || m_HideMobileInput);
        }

        /// <summary>
        /// Capture the OnBeginDrag callback from the EventSystem and ensure we should listen to the drag events to follow.
        /// </summary>
        /// <param name="eventData">The data passed by the EventSystem</param>
        public virtual void OnBeginDrag(PointerEventData eventData)
        {
            if (!MayDrag(eventData))
                return;

            m_UpdateDrag = true;
        }

        /// <summary>
        /// If we are able to drag, try and select the character range underneath the bounding rect.
        /// </summary>
        /// <param name="eventData"></param>
        public virtual void OnDrag(PointerEventData eventData)
        {
            if (!MayDrag(eventData))
                return;

            Vector2 position = Vector2.zero;
            if (!MultipleDisplayUtilities.GetRelativeMousePositionForDrag(eventData, ref position))
                return;

            Vector2 localMousePos;
            RectTransformUtility.ScreenPointToLocalPointInRectangle(textComponent.rectTransform, position, eventData.pressEventCamera, out localMousePos);
            caretSelectPositionInternal = GetCharacterIndexFromPosition(localMousePos) + m_DrawStart;

            MarkGeometryAsDirty();

            m_DragPositionOutOfBounds = !RectTransformUtility.RectangleContainsScreenPoint(textComponent.rectTransform, eventData.position, eventData.pressEventCamera);
            if (m_DragPositionOutOfBounds && m_DragCoroutine == null)
                m_DragCoroutine = StartCoroutine(MouseDragOutsideRect(eventData));

            eventData.Use();
        }

        IEnumerator MouseDragOutsideRect(PointerEventData eventData)
        {
            while (m_UpdateDrag && m_DragPositionOutOfBounds)
            {
                Vector2 position = Vector2.zero;
                if (!MultipleDisplayUtilities.GetRelativeMousePositionForDrag(eventData, ref position))
                    break;

                Vector2 localMousePos;
                RectTransformUtility.ScreenPointToLocalPointInRectangle(textComponent.rectTransform, position, eventData.pressEventCamera, out localMousePos);

                Rect rect = textComponent.rectTransform.rect;

                if (multiLine)
                {
                    if (localMousePos.y > rect.yMax)
                        MoveUp(true, true);
                    else if (localMousePos.y < rect.yMin)
                        MoveDown(true, true);
                }
                else
                {
                    if (localMousePos.x < rect.xMin)
                        MoveLeft(true, false);
                    else if (localMousePos.x > rect.xMax)
                        MoveRight(true, false);
                }
                UpdateLabel();
                float delay = multiLine ? kVScrollSpeed : kHScrollSpeed;
                if (m_WaitForSecondsRealtime == null)
                    m_WaitForSecondsRealtime = new WaitForSecondsRealtime(delay);
                else
                    m_WaitForSecondsRealtime.waitTime = delay;
                yield return m_WaitForSecondsRealtime;
            }
            m_DragCoroutine = null;
        }

        /// <summary>
        /// Capture the OnEndDrag callback from the EventSystem and cancel the listening of drag events.
        /// </summary>
        /// <param name="eventData">The eventData sent by the EventSystem.</param>
        public virtual void OnEndDrag(PointerEventData eventData)
        {
            if (!MayDrag(eventData))
                return;

            m_UpdateDrag = false;
        }

        /// <summary>
        /// The action to perform when the event system sends a pointer down Event.
        /// </summary>
        public override void OnPointerDown(PointerEventData eventData)
        {
            if (!MayDrag(eventData))
                return;

            EventSystem.current.SetSelectedGameObject(gameObject, eventData);

            bool hadFocusBefore = m_AllowInput;
            base.OnPointerDown(eventData);

            if (!InPlaceEditing())
            {
                if (m_Keyboard == null || !m_Keyboard.active)
                {
                    OnSelect(eventData);
                    return;
                }
            }

            // Only set caret position if we didn't just get focus now.
            // Otherwise it will overwrite the select all on focus.
            if (hadFocusBefore)
            {
                Vector2 localMousePos;

                RectTransformUtility.ScreenPointToLocalPointInRectangle(textComponent.rectTransform, eventData.pointerPressRaycast.screenPosition, eventData.pressEventCamera, out localMousePos);
                caretSelectPositionInternal = caretPositionInternal = GetCharacterIndexFromPosition(localMousePos) + m_DrawStart;
            }

            UpdateLabel();
            eventData.Use();
        }

        protected enum EditState
        {
            Continue,
            Finish
        }


        /// <summary>
        /// Process the Event and perform the appropriate action for that key.
        /// </summary>
        /// <param name="evt">The Event that is currently being processed.</param>
        /// <returns>If we should continue processing events or we have hit an end condition.</returns>
        protected EditState KeyPressed(Event evt)
        {
            var currentEventModifiers = evt.modifiers;
            bool ctrl = SystemInfo.operatingSystemFamily == OperatingSystemFamily.MacOSX ? (currentEventModifiers & EventModifiers.Command) != 0 : (currentEventModifiers & EventModifiers.Control) != 0;
            bool shift = (currentEventModifiers & EventModifiers.Shift) != 0;
            bool alt = (currentEventModifiers & EventModifiers.Alt) != 0;
            bool ctrlOnly = ctrl && !alt && !shift;
            bool shiftOnly = shift && !ctrl && !alt;

            switch (evt.keyCode)
            {
                case KeyCode.Backspace:
                {
                    Backspace();
                    return EditState.Continue;
                }

                case KeyCode.Delete:
                {
                    ForwardSpace();
                    return EditState.Continue;
                }

                case KeyCode.Home:
                {
                    MoveTextStart(shift);
                    return EditState.Continue;
                }

                case KeyCode.End:
                {
                    MoveTextEnd(shift);
                    return EditState.Continue;
                }

                // Select All
                case KeyCode.A:
                {
                    if (ctrlOnly)
                    {
                        SelectAll();
                        return EditState.Continue;
                    }
                    break;
                }

                // Copy
                case KeyCode.C:
                {
                    if (ctrlOnly)
                    {
                        if (inputType != InputType.Password)
                            clipboard = GetSelectedString();
                        else
                            clipboard = "";
                        return EditState.Continue;
                    }
                    break;
                }

                // Paste
                case KeyCode.V:
                {
                    if (ctrlOnly)
                    {
                        Append(clipboard);
                        UpdateLabel();
                        return EditState.Continue;
                    }
                    break;
                }

                // Cut
                case KeyCode.X:
                {
                    if (ctrlOnly)
                    {
                        if (inputType != InputType.Password)
                            clipboard = GetSelectedString();
                        else
                            clipboard = "";

                        Delete();
                        UpdateTouchKeyboardFromEditChanges();
                        SendOnValueChangedAndUpdateLabel();
                        return EditState.Continue;
                    }
                    break;
                }
                case KeyCode.Insert:
                {
                    // Copy via Insert key
                    if (ctrlOnly)
                    {
                        if (inputType != InputType.Password)
                            clipboard = GetSelectedString();
                        else
                            clipboard = "";
                        return EditState.Continue;
                    }
                    // Paste via insert key.
                    else if (shiftOnly)
                    {
                        Append(clipboard);
                        UpdateLabel();
                        return EditState.Continue;
                    }
                    break;
                }

                case KeyCode.LeftArrow:
                {
                    MoveLeft(shift, ctrl);
                    return EditState.Continue;
                }

                case KeyCode.RightArrow:
                {
                    MoveRight(shift, ctrl);
                    return EditState.Continue;
                }

                case KeyCode.UpArrow:
                {
                    MoveUp(shift);
                    return EditState.Continue;
                }

                case KeyCode.DownArrow:
                {
                    MoveDown(shift);
                    return EditState.Continue;
                }

                // Submit
                case KeyCode.Return:
                case KeyCode.KeypadEnter:
                {
                    if (lineType != LineType.MultiLineNewline)
                    {
                        return EditState.Finish;
                    }
                    break;
                }

                case KeyCode.Escape:
                {
                    m_WasCanceled = true;
                    return EditState.Finish;
                }
            }

            char c = evt.character;
            // Don't allow return chars or tabulator key to be entered into single line fields.
            if (!multiLine && (c == '\t' || c == '\r' || c == 10))
                return EditState.Continue;

            // Convert carriage return and end-of-text characters to newline.
            if (c == '\r' || (int)c == 3)
                c = '\n';

            if (IsValidChar(c))
            {
                Append(c);
            }

            if (c == 0)
            {
                if (compositionString.Length > 0)
                {
                    UpdateLabel();
                }
            }
            return EditState.Continue;
        }

        private bool IsValidChar(char c)
        {
            // Delete key on mac
            if ((int)c == 127)
                return false;
            // Accept newline and tab
            if (c == '\t' || c == '\n')
                return true;

            return m_TextComponent.font.HasCharacter(c);
        }

        /// <summary>
        /// Handle the specified event.
        /// </summary>
        private Event m_ProcessingEvent = new Event();

        /// <summary>
        /// Helper function to allow separate events to be processed by the InputField.
        /// </summary>
        /// <param name="e">The Event to process</param>
        public void ProcessEvent(Event e)
        {
            KeyPressed(e);
        }

        /// <summary>
        /// What to do when the event system sends a Update selected Event.
        /// </summary>
        /// <param name="eventData">The data on which to process.</param>
        public virtual void OnUpdateSelected(BaseEventData eventData)
        {
            if (!isFocused)
                return;

            bool consumedEvent = false;
            while (Event.PopEvent(m_ProcessingEvent))
            {
                if (m_ProcessingEvent.rawType == EventType.KeyDown)
                {
                    consumedEvent = true;
                    var shouldContinue = KeyPressed(m_ProcessingEvent);
                    if (shouldContinue == EditState.Finish)
                    {
                        DeactivateInputField();
                        break;
                    }
                }

                switch (m_ProcessingEvent.type)
                {
                    case EventType.ValidateCommand:
                    case EventType.ExecuteCommand:
                        switch (m_ProcessingEvent.commandName)
                        {
                            case "SelectAll":
                                SelectAll();
                                consumedEvent = true;
                                break;
                        }
                        break;
                }
            }

            if (consumedEvent)
                UpdateLabel();

            eventData.Use();
        }

        private string GetSelectedString()
        {
            if (!hasSelection)
                return "";

            int startPos = caretPositionInternal;
            int endPos = caretSelectPositionInternal;

            // Ensure startPos is always less then endPos to make the code simpler
            if (startPos > endPos)
            {
                int temp = startPos;
                startPos = endPos;
                endPos = temp;
            }

            return text.Substring(startPos, endPos - startPos);
        }

        private int FindtNextWordBegin()
        {
            if (caretSelectPositionInternal + 1 >= text.Length)
                return text.Length;

            int spaceLoc = text.IndexOfAny(kSeparators, caretSelectPositionInternal + 1);

            if (spaceLoc == -1)
                spaceLoc = text.Length;
            else
                spaceLoc++;

            return spaceLoc;
        }

        private void MoveRight(bool shift, bool ctrl)
        {
            if (hasSelection && !shift)
            {
                // By convention, if we have a selection and move right without holding shift,
                // we just place the cursor at the end.
                caretPositionInternal = caretSelectPositionInternal = Mathf.Max(caretPositionInternal, caretSelectPositionInternal);
                return;
            }

            int position;
            if (ctrl)
                position = FindtNextWordBegin();
            else
                position = caretSelectPositionInternal + 1;

            if (shift)
                caretSelectPositionInternal = position;
            else
                caretSelectPositionInternal = caretPositionInternal = position;
        }

        private int FindtPrevWordBegin()
        {
            if (caretSelectPositionInternal - 2 < 0)
                return 0;

            int spaceLoc = text.LastIndexOfAny(kSeparators, caretSelectPositionInternal - 2);

            if (spaceLoc == -1)
                spaceLoc = 0;
            else
                spaceLoc++;

            return spaceLoc;
        }

        private void MoveLeft(bool shift, bool ctrl)
        {
            if (hasSelection && !shift)
            {
                // By convention, if we have a selection and move left without holding shift,
                // we just place the cursor at the start.
                caretPositionInternal = caretSelectPositionInternal = Mathf.Min(caretPositionInternal, caretSelectPositionInternal);
                return;
            }

            int position;
            if (ctrl)
                position = FindtPrevWordBegin();
            else
                position = caretSelectPositionInternal - 1;

            if (shift)
                caretSelectPositionInternal = position;
            else
                caretSelectPositionInternal = caretPositionInternal = position;
        }

        private int DetermineCharacterLine(int charPos, TextGenerator generator)
        {
            for (int i = 0; i < generator.lineCount - 1; ++i)
            {
                if (generator.lines[i + 1].startCharIdx > charPos)
                    return i;
            }

            return generator.lineCount - 1;
        }

        /// <summary>
        ///  Use cachedInputTextGenerator as the y component for the UICharInfo is not required
        /// </summary>

        private int LineUpCharacterPosition(int originalPos, bool goToFirstChar)
        {
            if (originalPos >= cachedInputTextGenerator.characters.Count)
                return 0;

            UICharInfo originChar = cachedInputTextGenerator.characters[originalPos];
            int originLine = DetermineCharacterLine(originalPos, cachedInputTextGenerator);

            // We are on the first line return first character
            if (originLine <= 0)
                return goToFirstChar ? 0 : originalPos;

            int endCharIdx = cachedInputTextGenerator.lines[originLine].startCharIdx - 1;

            for (int i = cachedInputTextGenerator.lines[originLine - 1].startCharIdx; i < endCharIdx; ++i)
            {
                if (cachedInputTextGenerator.characters[i].cursorPos.x >= originChar.cursorPos.x)
                    return i;
            }
            return endCharIdx;
        }

        /// <summary>
        ///  Use cachedInputTextGenerator as the y component for the UICharInfo is not required
        /// </summary>

        private int LineDownCharacterPosition(int originalPos, bool goToLastChar)
        {
            if (originalPos >= cachedInputTextGenerator.characterCountVisible)
                return text.Length;

            UICharInfo originChar = cachedInputTextGenerator.characters[originalPos];
            int originLine = DetermineCharacterLine(originalPos, cachedInputTextGenerator);

            // We are on the last line return last character
            if (originLine + 1 >= cachedInputTextGenerator.lineCount)
                return goToLastChar ? text.Length : originalPos;

            // Need to determine end line for next line.
            int endCharIdx = GetLineEndPosition(cachedInputTextGenerator, originLine + 1);

            for (int i = cachedInputTextGenerator.lines[originLine + 1].startCharIdx; i < endCharIdx; ++i)
            {
                if (cachedInputTextGenerator.characters[i].cursorPos.x >= originChar.cursorPos.x)
                    return i;
            }
            return endCharIdx;
        }

        private void MoveDown(bool shift)
        {
            MoveDown(shift, true);
        }

        private void MoveDown(bool shift, bool goToLastChar)
        {
            if (hasSelection && !shift)
            {
                // If we have a selection and press down without shift,
                // set caret position to end of selection before we move it down.
                caretPositionInternal = caretSelectPositionInternal = Mathf.Max(caretPositionInternal, caretSelectPositionInternal);
            }

            int position = multiLine ? LineDownCharacterPosition(caretSelectPositionInternal, goToLastChar) : text.Length;

            if (shift)
                caretSelectPositionInternal = position;
            else
                caretPositionInternal = caretSelectPositionInternal = position;
        }

        private void MoveUp(bool shift)
        {
            MoveUp(shift, true);
        }

        private void MoveUp(bool shift, bool goToFirstChar)
        {
            if (hasSelection && !shift)
            {
                // If we have a selection and press up without shift,
                // set caret position to start of selection before we move it up.
                caretPositionInternal = caretSelectPositionInternal = Mathf.Min(caretPositionInternal, caretSelectPositionInternal);
            }

            int position = multiLine ? LineUpCharacterPosition(caretSelectPositionInternal, goToFirstChar) : 0;

            if (shift)
                caretSelectPositionInternal = position;
            else
                caretSelectPositionInternal = caretPositionInternal = position;
        }

        private void Delete()
        {
            if (m_ReadOnly)
                return;

            if (caretPositionInternal == caretSelectPositionInternal)
                return;

            if (caretPositionInternal < caretSelectPositionInternal)
            {
                m_Text = text.Substring(0, caretPositionInternal) + text.Substring(caretSelectPositionInternal, text.Length - caretSelectPositionInternal);
                caretSelectPositionInternal = caretPositionInternal;
            }
            else
            {
                m_Text = text.Substring(0, caretSelectPositionInternal) + text.Substring(caretPositionInternal, text.Length - caretPositionInternal);
                caretPositionInternal = caretSelectPositionInternal;
            }
        }

        private void ForwardSpace()
        {
            if (m_ReadOnly)
                return;

            if (hasSelection)
            {
                Delete();
                UpdateTouchKeyboardFromEditChanges();
                SendOnValueChangedAndUpdateLabel();
            }
            else
            {
                if (caretPositionInternal < text.Length)
                {
                    m_Text = text.Remove(caretPositionInternal, 1);

                    UpdateTouchKeyboardFromEditChanges();
                    SendOnValueChangedAndUpdateLabel();
                }
            }
        }

        private void Backspace()
        {
            if (m_ReadOnly)
                return;

            if (hasSelection)
            {
                Delete();
                UpdateTouchKeyboardFromEditChanges();
                SendOnValueChangedAndUpdateLabel();
            }
            else
            {
                if (caretPositionInternal > 0)
                {
                    m_Text = text.Remove(caretPositionInternal - 1, 1);
                    caretSelectPositionInternal = caretPositionInternal = caretPositionInternal - 1;

                    UpdateTouchKeyboardFromEditChanges();
                    SendOnValueChangedAndUpdateLabel();
                }
            }
        }

        // Insert the character and update the label.
        private void Insert(char c)
        {
            if (m_ReadOnly)
                return;

            string replaceString = c.ToString();
            Delete();

            // Can't go past the character limit
            if (characterLimit > 0 && text.Length >= characterLimit)
                return;

            m_Text = text.Insert(m_CaretPosition, replaceString);
            caretSelectPositionInternal = caretPositionInternal += replaceString.Length;

            UpdateTouchKeyboardFromEditChanges();
            SendOnValueChanged();
        }

        private void UpdateTouchKeyboardFromEditChanges()
        {
            // Update the TouchKeyboard's text from edit changes
            // if in-place editing is allowed
            if (m_Keyboard != null && InPlaceEditing())
            {
                m_Keyboard.text = m_Text;
            }
        }

        private void SendOnValueChangedAndUpdateLabel()
        {
            SendOnValueChanged();
            UpdateLabel();
        }

        private void SendOnValueChanged()
        {
            UISystemProfilerApi.AddMarker("InputField.value", this);
            if (onValueChanged != null)
                onValueChanged.Invoke(text);
        }

        /// <summary>
        /// Convenience function to make functionality to send the ::ref::SubmitEvent easier.
        /// </summary>
        protected void SendOnSubmit()
        {
            UISystemProfilerApi.AddMarker("InputField.onSubmit", this);
            if (onEndEdit != null)
                onEndEdit.Invoke(m_Text);
        }

        /// <summary>
        /// Append the specified text to the end of the current text string. Appends character by character testing validation criteria.
        /// </summary>
        /// <param name="input">The String to append.</param>
        protected virtual void Append(string input)
        {
            if (m_ReadOnly)
                return;

            if (!InPlaceEditing())
                return;

            for (int i = 0, imax = input.Length; i < imax; ++i)
            {
                char c = input[i];

                if (c >= ' ' || c == '\t' || c == '\r' || c == 10 || c == '\n')
                {
                    Append(c);
                }
            }
        }

        // cf. TextGenerator.cpp
        private const int k_MaxTextLength = UInt16.MaxValue / 4 - 1;

        /// <summary>
        /// Append a character to the input field, taking into account the validation of each character.
        /// </summary>
        /// <param name="input">Character to append.</param>
        protected virtual void Append(char input)
        {
            // We do not currently support surrogate pairs
            if (char.IsSurrogate(input))
                return;

            if (m_ReadOnly || text.Length >= k_MaxTextLength)
                return;

            if (!InPlaceEditing())
                return;

            // If we have an input validator, validate the input first
            int insertionPoint = Math.Min(selectionFocusPosition, selectionAnchorPosition);

            //Get the text based on selection for validation instead of whole text(case 1253193).
            var validateText = text;
            if (selectionFocusPosition != selectionAnchorPosition)
            {
                if (caretPositionInternal < caretSelectPositionInternal)
                {
                    validateText = text.Substring(0, caretPositionInternal) + text.Substring(caretSelectPositionInternal, text.Length - caretSelectPositionInternal);
                }
                else
                {
                    validateText = text.Substring(0, caretSelectPositionInternal) + text.Substring(caretPositionInternal, text.Length - caretPositionInternal);
                }
            }

            if (onValidateInput != null)
                input = onValidateInput(validateText, insertionPoint, input);
            else if (characterValidation != CharacterValidation.None)
                input = Validate(validateText, insertionPoint, input);

            // If the input is invalid, skip it
            if (input == 0)
                return;

            // Append the character and update the label
            Insert(input);
        }

        /// <summary>
        /// Update the Text associated with this input field.
        /// </summary>
        protected void UpdateLabel()
        {
            if (m_TextComponent != null && m_TextComponent.font != null && !m_PreventFontCallback)
            {
                // TextGenerator.Populate invokes a callback that's called for anything
                // that needs to be updated when the data for that font has changed.
                // This makes all Text components that use that font update their vertices.
                // In turn, this makes the InputField that's associated with that Text component
                // update its label by calling this UpdateLabel method.
                // This is a recursive call we want to prevent, since it makes the InputField
                // update based on font data that didn't yet finish executing, or alternatively
                // hang on infinite recursion, depending on whether the cached value is cached
                // before or after the calculation.
                //
                // This callback also occurs when assigning text to our Text component, i.e.,
                // m_TextComponent.text = processed;

                m_PreventFontCallback = true;

                string fullText;
                if (EventSystem.current != null && gameObject == EventSystem.current.currentSelectedGameObject && compositionString.Length > 0)
                    fullText = text.Substring(0, m_CaretPosition) + compositionString + text.Substring(m_CaretPosition);
                else
                    fullText = text;

                string processed;
                if (inputType == InputType.Password)
                    processed = new string(asteriskChar, fullText.Length);
                else
                    processed = fullText;

                bool isEmpty = string.IsNullOrEmpty(fullText);

                if (m_Placeholder != null)
                    m_Placeholder.enabled = isEmpty;

                // If not currently editing the text, set the visible range to the whole text.
                // The UpdateLabel method will then truncate it to the part that fits inside the Text area.
                // We can't do this when text is being edited since it would discard the current scroll,
                // which is defined by means of the m_DrawStart and m_DrawEnd indices.
                if (!m_AllowInput)
                {
                    m_DrawStart = 0;
                    m_DrawEnd = m_Text.Length;
                }

                if (!isEmpty)
                {
                    // Determine what will actually fit into the given line
                    Vector2 extents = m_TextComponent.rectTransform.rect.size;

                    var settings = m_TextComponent.GetGenerationSettings(extents);
                    settings.generateOutOfBounds = true;

                    cachedInputTextGenerator.PopulateWithErrors(processed, settings, gameObject);

                    SetDrawRangeToContainCaretPosition(caretSelectPositionInternal);

                    processed = processed.Substring(m_DrawStart, Mathf.Min(m_DrawEnd, processed.Length) - m_DrawStart);

                    SetCaretVisible();
                }
                m_TextComponent.text = processed;
                MarkGeometryAsDirty();
                m_PreventFontCallback = false;
            }
        }

        private bool IsSelectionVisible()
        {
            if (m_DrawStart > caretPositionInternal || m_DrawStart > caretSelectPositionInternal)
                return false;

            if (m_DrawEnd < caretPositionInternal || m_DrawEnd < caretSelectPositionInternal)
                return false;

            return true;
        }

        private static int GetLineStartPosition(TextGenerator gen, int line)
        {
            line = Mathf.Clamp(line, 0, gen.lines.Count - 1);
            return gen.lines[line].startCharIdx;
        }

        private static int GetLineEndPosition(TextGenerator gen, int line)
        {
            line = Mathf.Max(line, 0);
            if (line + 1 < gen.lines.Count)
                return gen.lines[line + 1].startCharIdx - 1;
            return gen.characterCountVisible;
        }

        private void SetDrawRangeToContainCaretPosition(int caretPos)
        {
            // We don't have any generated lines generation is not valid.
            if (cachedInputTextGenerator.lineCount <= 0)
                return;

            // the extents gets modified by the pixel density, so we need to use the generated extents since that will be in the same 'space' as
            // the values returned by the TextGenerator.lines[x].height for instance.
            Vector2 extents = cachedInputTextGenerator.rectExtents.size;

            if (multiLine)
            {
                var lines = cachedInputTextGenerator.lines;
                int caretLine = DetermineCharacterLine(caretPos, cachedInputTextGenerator);

                if (caretPos > m_DrawEnd)
                {
                    // Caret comes after drawEnd, so we need to move drawEnd to the end of the line with the caret
                    m_DrawEnd = GetLineEndPosition(cachedInputTextGenerator, caretLine);
                    float bottomY = lines[caretLine].topY - lines[caretLine].height;
                    if (caretLine == lines.Count - 1)
                    {
                        // Remove interline spacing on last line.
                        bottomY += lines[caretLine].leading;
                    }
                    int startLine = caretLine;
                    while (startLine > 0)
                    {
                        float topY = lines[startLine - 1].topY;
                        if (topY - bottomY > extents.y)
                            break;
                        startLine--;
                    }
                    m_DrawStart = GetLineStartPosition(cachedInputTextGenerator, startLine);
                }
                else
                {
                    if (caretPos < m_DrawStart)
                    {
                        // Caret comes before drawStart, so we need to move drawStart to an earlier line start that comes before caret.
                        m_DrawStart = GetLineStartPosition(cachedInputTextGenerator, caretLine);
                    }

                    int startLine = DetermineCharacterLine(m_DrawStart, cachedInputTextGenerator);
                    int endLine = startLine;

                    float topY = lines[startLine].topY;
                    float bottomY = lines[endLine].topY - lines[endLine].height;

                    if (endLine == lines.Count - 1)
                    {
                        // Remove interline spacing on last line.
                        bottomY += lines[endLine].leading;
                    }

                    while (endLine < lines.Count - 1)
                    {
                        bottomY = lines[endLine + 1].topY - lines[endLine + 1].height;

                        if (endLine + 1 == lines.Count - 1)
                        {
                            // Remove interline spacing on last line.
                            bottomY += lines[endLine + 1].leading;
                        }

                        if (topY - bottomY > extents.y)
                            break;
                        ++endLine;
                    }

                    m_DrawEnd = GetLineEndPosition(cachedInputTextGenerator, endLine);

                    while (startLine > 0)
                    {
                        topY = lines[startLine - 1].topY;
                        if (topY - bottomY > extents.y)
                            break;
                        startLine--;
                    }
                    m_DrawStart = GetLineStartPosition(cachedInputTextGenerator, startLine);
                }
            }
            else
            {
                var characters = cachedInputTextGenerator.characters;
                if (m_DrawEnd > cachedInputTextGenerator.characterCountVisible)
                    m_DrawEnd = cachedInputTextGenerator.characterCountVisible;

                float width = 0.0f;
                if (caretPos > m_DrawEnd || (caretPos == m_DrawEnd && m_DrawStart > 0))
                {
                    // fit characters from the caretPos leftward
                    m_DrawEnd = caretPos;
                    for (m_DrawStart = m_DrawEnd - 1; m_DrawStart >= 0; --m_DrawStart)
                    {
                        if (width + characters[m_DrawStart].charWidth > extents.x)
                            break;

                        width += characters[m_DrawStart].charWidth;
                    }
                    ++m_DrawStart;  // move right one to the last character we could fit on the left
                }
                else
                {
                    if (caretPos < m_DrawStart)
                        m_DrawStart = caretPos;

                    m_DrawEnd = m_DrawStart;
                }

                // fit characters rightward
                for (; m_DrawEnd < cachedInputTextGenerator.characterCountVisible; ++m_DrawEnd)
                {
                    width += characters[m_DrawEnd].charWidth;
                    if (width > extents.x)
                        break;
                }
            }
        }

        /// <summary>
        /// Force the label to update immediatly. This will recalculate the positioning of the caret and the visible text.
        /// </summary>
        public void ForceLabelUpdate()
        {
            UpdateLabel();
        }

        private void MarkGeometryAsDirty()
        {
#if UNITY_EDITOR
            if (!Application.isPlaying || UnityEditor.PrefabUtility.IsPartOfPrefabAsset(gameObject))
                return;
#endif

            CanvasUpdateRegistry.RegisterCanvasElementForGraphicRebuild(this);
        }

        /// <summary>
        /// Rebuild the input fields geometry. (caret and highlight).
        /// </summary>
        /// <param name="update">Which update loop we are in.</param>
        public virtual void Rebuild(CanvasUpdate update)
        {
            switch (update)
            {
                case CanvasUpdate.LatePreRender:
                    UpdateGeometry();
                    break;
            }
        }

        /// <summary>
        /// See ICanvasElement.LayoutComplete. Does nothing by default.
        /// </summary>
        public virtual void LayoutComplete()
        {}

        /// <summary>
        /// See ICanvasElement.GraphicUpdateComplete. Does nothing by default.
        /// </summary>
        public virtual void GraphicUpdateComplete()
        {}

        private void UpdateGeometry()
        {
#if UNITY_EDITOR
            if (!Application.isPlaying)
                return;
#endif
            // No need to draw a cursor on mobile as its handled by the devices keyboard.
            if (!InPlaceEditing() && !shouldHideMobileInput)
                return;

            if (m_CachedInputRenderer == null && m_TextComponent != null)
            {
                GameObject go = new GameObject(transform.name + " Input Caret", typeof(RectTransform), typeof(CanvasRenderer));
                go.hideFlags = HideFlags.DontSave;
                go.transform.SetParent(m_TextComponent.transform.parent);
                go.transform.SetAsFirstSibling();
                go.layer = gameObject.layer;

                caretRectTrans = go.GetComponent<RectTransform>();
                m_CachedInputRenderer = go.GetComponent<CanvasRenderer>();
                m_CachedInputRenderer.SetMaterial(m_TextComponent.GetModifiedMaterial(Graphic.defaultGraphicMaterial), Texture2D.whiteTexture);

                // Needed as if any layout is present we want the caret to always be the same as the text area.
                go.AddComponent<LayoutElement>().ignoreLayout = true;

                AssignPositioningIfNeeded();
            }

            if (m_CachedInputRenderer == null)
                return;

            OnFillVBO(mesh);
            m_CachedInputRenderer.SetMesh(mesh);
        }

        private void AssignPositioningIfNeeded()
        {
            if (m_TextComponent != null && caretRectTrans != null &&
                (caretRectTrans.localPosition != m_TextComponent.rectTransform.localPosition ||
                 caretRectTrans.localRotation != m_TextComponent.rectTransform.localRotation ||
                 caretRectTrans.localScale != m_TextComponent.rectTransform.localScale ||
                 caretRectTrans.anchorMin != m_TextComponent.rectTransform.anchorMin ||
                 caretRectTrans.anchorMax != m_TextComponent.rectTransform.anchorMax ||
                 caretRectTrans.anchoredPosition != m_TextComponent.rectTransform.anchoredPosition ||
                 caretRectTrans.sizeDelta != m_TextComponent.rectTransform.sizeDelta ||
                 caretRectTrans.pivot != m_TextComponent.rectTransform.pivot))
            {
                caretRectTrans.localPosition = m_TextComponent.rectTransform.localPosition;
                caretRectTrans.localRotation = m_TextComponent.rectTransform.localRotation;
                caretRectTrans.localScale = m_TextComponent.rectTransform.localScale;
                caretRectTrans.anchorMin = m_TextComponent.rectTransform.anchorMin;
                caretRectTrans.anchorMax = m_TextComponent.rectTransform.anchorMax;
                caretRectTrans.anchoredPosition = m_TextComponent.rectTransform.anchoredPosition;
                caretRectTrans.sizeDelta = m_TextComponent.rectTransform.sizeDelta;
                caretRectTrans.pivot = m_TextComponent.rectTransform.pivot;
            }
        }

        private void OnFillVBO(Mesh vbo)
        {
            using (var helper = new VertexHelper())
            {
                if (!isFocused)
                {
                    helper.FillMesh(vbo);
                    return;
                }

                Vector2 roundingOffset = m_TextComponent.PixelAdjustPoint(Vector2.zero);
                if (!hasSelection)
                    GenerateCaret(helper, roundingOffset);
                else
                    GenerateHighlight(helper, roundingOffset);

                helper.FillMesh(vbo);
            }
        }

        private void GenerateCaret(VertexHelper vbo, Vector2 roundingOffset)
        {
            if (!m_CaretVisible)
                return;

            if (m_CursorVerts == null)
            {
                CreateCursorVerts();
            }

            float width = m_CaretWidth;
            int adjustedPos = Mathf.Max(0, caretPositionInternal - m_DrawStart);
            TextGenerator gen = m_TextComponent.cachedTextGenerator;

            if (gen == null)
                return;

            if (gen.lineCount == 0)
                return;

            Vector2 startPosition = Vector2.zero;

            // Calculate startPosition
            if (adjustedPos < gen.characters.Count)
            {
                UICharInfo cursorChar = gen.characters[adjustedPos];
                startPosition.x = cursorChar.cursorPos.x;
            }
            startPosition.x /= m_TextComponent.pixelsPerUnit;

            // TODO: Only clamp when Text uses horizontal word wrap.
            if (startPosition.x > m_TextComponent.rectTransform.rect.xMax)
                startPosition.x = m_TextComponent.rectTransform.rect.xMax;

            int characterLine = DetermineCharacterLine(adjustedPos, gen);
            startPosition.y = gen.lines[characterLine].topY / m_TextComponent.pixelsPerUnit;
            float height = gen.lines[characterLine].height / m_TextComponent.pixelsPerUnit;

            for (int i = 0; i < m_CursorVerts.Length; i++)
                m_CursorVerts[i].color = caretColor;

            m_CursorVerts[0].position = new Vector3(startPosition.x, startPosition.y - height, 0.0f);
            m_CursorVerts[1].position = new Vector3(startPosition.x + width, startPosition.y - height, 0.0f);
            m_CursorVerts[2].position = new Vector3(startPosition.x + width, startPosition.y, 0.0f);
            m_CursorVerts[3].position = new Vector3(startPosition.x, startPosition.y, 0.0f);

            if (roundingOffset != Vector2.zero)
            {
                for (int i = 0; i < m_CursorVerts.Length; i++)
                {
                    UIVertex uiv = m_CursorVerts[i];
                    uiv.position.x += roundingOffset.x;
                    uiv.position.y += roundingOffset.y;
                }
            }

            vbo.AddUIVertexQuad(m_CursorVerts);

            int screenHeight = Screen.height;
            // Multiple display support only when not the main display. For display 0 the reported
            // resolution is always the desktops resolution since its part of the display API,
            // so we use the standard none multiple display method. (case 741751)
            int displayIndex = m_TextComponent.canvas.targetDisplay;
            if (displayIndex > 0 && displayIndex < Display.displays.Length)
                screenHeight = Display.displays[displayIndex].renderingHeight;

            // Calculate position of IME Window in screen space.
            Camera cameraRef;
            if (m_TextComponent.canvas.renderMode == RenderMode.ScreenSpaceOverlay)
                cameraRef = null;
            else
                cameraRef = m_TextComponent.canvas.worldCamera;

            Vector3 cursorPosition = m_CachedInputRenderer.gameObject.transform.TransformPoint(m_CursorVerts[0].position);
            Vector2 screenPosition = RectTransformUtility.WorldToScreenPoint(cameraRef, cursorPosition);
            screenPosition.y = screenHeight - screenPosition.y;

            if (input != null)
                input.compositionCursorPos = screenPosition;
        }

        private void CreateCursorVerts()
        {
            m_CursorVerts = new UIVertex[4];

            for (int i = 0; i < m_CursorVerts.Length; i++)
            {
                m_CursorVerts[i] = UIVertex.simpleVert;
                m_CursorVerts[i].uv0 = Vector2.zero;
            }
        }

        private void GenerateHighlight(VertexHelper vbo, Vector2 roundingOffset)
        {
            int startChar = Mathf.Max(0, caretPositionInternal - m_DrawStart);
            int endChar = Mathf.Max(0, caretSelectPositionInternal - m_DrawStart);

            // Ensure pos is always less then selPos to make the code simpler
            if (startChar > endChar)
            {
                int temp = startChar;
                startChar = endChar;
                endChar = temp;
            }

            endChar -= 1;
            TextGenerator gen = m_TextComponent.cachedTextGenerator;

            if (gen.lineCount <= 0)
                return;

            int currentLineIndex = DetermineCharacterLine(startChar, gen);

            int lastCharInLineIndex = GetLineEndPosition(gen, currentLineIndex);

            UIVertex vert = UIVertex.simpleVert;
            vert.uv0 = Vector2.zero;
            vert.color = selectionColor;

            int currentChar = startChar;
            while (currentChar <= endChar && currentChar < gen.characterCount)
            {
                if (currentChar == lastCharInLineIndex || currentChar == endChar)
                {
                    UICharInfo startCharInfo = gen.characters[startChar];
                    UICharInfo endCharInfo = gen.characters[currentChar];
                    Vector2 startPosition = new Vector2(startCharInfo.cursorPos.x / m_TextComponent.pixelsPerUnit, gen.lines[currentLineIndex].topY / m_TextComponent.pixelsPerUnit);
                    Vector2 endPosition = new Vector2((endCharInfo.cursorPos.x + endCharInfo.charWidth) / m_TextComponent.pixelsPerUnit, startPosition.y - gen.lines[currentLineIndex].height / m_TextComponent.pixelsPerUnit);

                    // Checking xMin as well due to text generator not setting position if char is not rendered.
                    if (endPosition.x > m_TextComponent.rectTransform.rect.xMax || endPosition.x < m_TextComponent.rectTransform.rect.xMin)
                        endPosition.x = m_TextComponent.rectTransform.rect.xMax;

                    var startIndex = vbo.currentVertCount;
                    vert.position = new Vector3(startPosition.x, endPosition.y, 0.0f) + (Vector3)roundingOffset;
                    vbo.AddVert(vert);

                    vert.position = new Vector3(endPosition.x, endPosition.y, 0.0f) + (Vector3)roundingOffset;
                    vbo.AddVert(vert);

                    vert.position = new Vector3(endPosition.x, startPosition.y, 0.0f) + (Vector3)roundingOffset;
                    vbo.AddVert(vert);

                    vert.position = new Vector3(startPosition.x, startPosition.y, 0.0f) + (Vector3)roundingOffset;
                    vbo.AddVert(vert);

                    vbo.AddTriangle(startIndex, startIndex + 1, startIndex + 2);
                    vbo.AddTriangle(startIndex + 2, startIndex + 3, startIndex + 0);

                    startChar = currentChar + 1;
                    currentLineIndex++;

                    lastCharInLineIndex = GetLineEndPosition(gen, currentLineIndex);
                }
                currentChar++;
            }
        }

        /// <summary>
        /// Predefined validation functionality for different characterValidation types.
        /// </summary>
        /// <param name="text">The whole text string to validate.</param>
        /// <param name="pos">The position at which the current character is being inserted.</param>
        /// <param name="ch">The character that is being inserted</param>
        /// <returns>The character that should be inserted.</returns>
        protected char Validate(string text, int pos, char ch)
        {
            // Validation is disabled
            if (characterValidation == CharacterValidation.None || !enabled)
                return ch;

            if (characterValidation == CharacterValidation.Integer || characterValidation == CharacterValidation.Decimal)
            {
                // Integer and decimal
                bool cursorBeforeDash = (pos == 0 && text.Length > 0 && text[0] == '-');
                bool dashInSelection = text.Length > 0 && text[0] == '-' && ((caretPositionInternal == 0 && caretSelectPositionInternal > 0) || (caretSelectPositionInternal == 0 && caretPositionInternal > 0));
                bool selectionAtStart = caretPositionInternal == 0 || caretSelectPositionInternal == 0;
                if (!cursorBeforeDash || dashInSelection)
                {
                    if (ch >= '0' && ch <= '9') return ch;
                    if (ch == '-' && (pos == 0 || selectionAtStart)) return ch;
                    if ((ch == '.' || ch == ',') && characterValidation == CharacterValidation.Decimal && text.IndexOfAny(new[] { '.', ',' }) == -1) return ch;
                }
            }
            else if (characterValidation == CharacterValidation.Alphanumeric)
            {
                // All alphanumeric characters
                if (ch >= 'A' && ch <= 'Z') return ch;
                if (ch >= 'a' && ch <= 'z') return ch;
                if (ch >= '0' && ch <= '9') return ch;
            }
            else if (characterValidation == CharacterValidation.Name)
            {
                // FIXME: some actions still lead to invalid input:
                //        - Hitting delete in front of an uppercase letter
                //        - Selecting an uppercase letter and deleting it
                //        - Typing some text, hitting Home and typing more text (we then have an uppercase letter in the middle of a word)
                //        - Typing some text, hitting Home and typing a space (we then have a leading space)
                //        - Erasing a space between two words (we then have an uppercase letter in the middle of a word)
                //        - We accept a trailing space
                //        - We accept the insertion of a space between two lowercase letters.
                //        - Typing text in front of an existing uppercase letter
                //        - ... and certainly more
                //
                // The rule we try to implement are too complex for this kind of verification.

                if (char.IsLetter(ch))
                {
                    // Character following a space should be in uppercase.
                    if (char.IsLower(ch) && ((pos == 0) || (text[pos - 1] == ' ')))
                    {
                        return char.ToUpper(ch);
                    }

                    // Character not following a space or an apostrophe should be in lowercase.
                    if (char.IsUpper(ch) && (pos > 0) && (text[pos - 1] != ' ') && (text[pos - 1] != '\''))
                    {
                        return char.ToLower(ch);
                    }

                    return ch;
                }

                if (ch == '\'')
                {
                    // Don't allow more than one apostrophe
                    if (!text.Contains("'"))
                        // Don't allow consecutive spaces and apostrophes.
                        if (!(((pos > 0) && ((text[pos - 1] == ' ') || (text[pos - 1] == '\''))) ||
                              ((pos < text.Length) && ((text[pos] == ' ') || (text[pos] == '\'')))))
                            return ch;
                }

                if (ch == ' ')
                {
                    if (pos != 0) // Don't allow leading spaces
                    {
                        // Don't allow consecutive spaces and apostrophes.
                        if (!(((pos > 0) && ((text[pos - 1] == ' ') || (text[pos - 1] == '\''))) ||
                              ((pos < text.Length) && ((text[pos] == ' ') || (text[pos] == '\'')))))
                            return ch;
                    }
                }
            }
            else if (characterValidation == CharacterValidation.EmailAddress)
            {
                // From StackOverflow about allowed characters in email addresses:
                // Uppercase and lowercase English letters (a-z, A-Z)
                // Digits 0 to 9
                // Characters ! # $ % & ' * + - / = ? ^ _ ` { | } ~
                // Character . (dot, period, full stop) provided that it is not the first or last character,
                // and provided also that it does not appear two or more times consecutively.

                if (ch >= 'A' && ch <= 'Z') return ch;
                if (ch >= 'a' && ch <= 'z') return ch;
                if (ch >= '0' && ch <= '9') return ch;
                if (ch == '@' && text.IndexOf('@') == -1) return ch;
                if (kEmailSpecialCharacters.IndexOf(ch) != -1) return ch;
                if (ch == '.')
                {
                    char lastChar = (text.Length > 0) ? text[Mathf.Clamp(pos, 0, text.Length - 1)] : ' ';
                    char nextChar = (text.Length > 0) ? text[Mathf.Clamp(pos + 1, 0, text.Length - 1)] : '\n';
                    if (lastChar != '.' && nextChar != '.')
                        return ch;
                }
            }
            return (char)0;
        }

        /// <summary>
        /// Function to activate the InputField to begin processing Events.
        /// </summary>
        /// <remarks>
        /// Will only activate if deactivated.
        /// </remarks>
        /// <example>
        /// <code>
        /// using UnityEngine;
        /// using System.Collections;
        /// using UnityEngine.UI;
        ///
        /// public class Example : MonoBehaviour
        /// {
        ///     public InputField mainInputField;
        ///
        ///     // Activate the main input field when the scene starts.
        ///     void Start()
        ///     {
        ///         mainInputField.ActivateInputField();
        ///     }
        /// }
        /// </code>
        /// </example>
        public void ActivateInputField()
        {
            if (m_TextComponent == null || m_TextComponent.font == null || !IsActive() || !IsInteractable())
                return;

            if (isFocused)
            {
                if (m_Keyboard != null && !m_Keyboard.active)
                {
                    m_Keyboard.active = true;
                    m_Keyboard.text = m_Text;
                }
            }

            m_ShouldActivateNextUpdate = true;
        }

        private void ActivateInputFieldInternal()
        {
            if (EventSystem.current == null)
                return;

            if (EventSystem.current.currentSelectedGameObject != gameObject)
                EventSystem.current.SetSelectedGameObject(gameObject);

            // Cache the value of isInPlaceEditingAllowed, because on UWP this involves calling into native code
            // Usually, the value only needs to be updated once when the TouchKeyboard is opened; however, on Chrome OS,
            // we check repeatedly to see if the in-place editing state has changed, so we can take action.
            m_TouchKeyboardAllowsInPlaceEditing = TouchScreenKeyboard.isInPlaceEditingAllowed;

            if (TouchScreenKeyboardShouldBeUsed())
            {
                if (input != null && input.touchSupported)
                {
                    TouchScreenKeyboard.hideInput = shouldHideMobileInput;
                }
                m_Keyboard = (inputType == InputType.Password) ?
                    TouchScreenKeyboard.Open(m_Text, keyboardType, false, multiLine, true, false, "", characterLimit) :
                    TouchScreenKeyboard.Open(m_Text, keyboardType, inputType == InputType.AutoCorrect, multiLine, false, false, "", characterLimit);

                // If TouchKeyboard doesn't support InPlaceEditing don't call OnFocus as mobile doesn't properly support select all
                // Just set it to the end of the text (where it would move when typing starts)
                if (!m_TouchKeyboardAllowsInPlaceEditing)
                {
                    MoveTextEnd(false);
                }
            }

            // Perform normal OnFocus routine if platform supports it
            if (!TouchScreenKeyboard.isSupported || m_TouchKeyboardAllowsInPlaceEditing)
            {
                if (input != null)
                    input.imeCompositionMode = IMECompositionMode.On;
                OnFocus();
            }
            m_AllowInput = true;
            m_OriginalText = text;
            m_WasCanceled = false;
            SetCaretVisible();
            UpdateLabel();
        }

        /// <summary>
        /// What to do when the event system sends a submit Event.
        /// </summary>
        /// <param name="eventData">The data on which to process</param>
        public override void OnSelect(BaseEventData eventData)
        {
            base.OnSelect(eventData);

            if (shouldActivateOnSelect)
                ActivateInputField();
        }

        /// <summary>
        /// What to do when the event system sends a pointer click Event
        /// </summary>
        /// <param name="eventData">The data on which to process</param>
        public virtual void OnPointerClick(PointerEventData eventData)
        {
            if (eventData.button != PointerEventData.InputButton.Left)
                return;

            ActivateInputField();
        }

        /// <summary>
        /// Function to deactivate the InputField to stop the processing of Events and send OnSubmit if not canceled.
        /// </summary>
        /// <example>
        /// <code>
        /// using UnityEngine;
        /// using System.Collections;
        /// using UnityEngine.UI; // Required when Using UI elements.
        ///
        /// public class Example : MonoBehaviour
        /// {
        ///     public InputField mainInputField;
        ///
        ///     // Deactivates the main input field when the scene starts.
        ///     void Start()
        ///     {
        ///         mainInputField.DeactivateInputField();
        ///     }
        /// }
        /// </code>
        /// </example>
        public void DeactivateInputField()
        {
            // Not activated do nothing.
            if (!m_AllowInput)
                return;

            m_HasDoneFocusTransition = false;
            m_AllowInput = false;

            if (m_Placeholder != null)
                m_Placeholder.enabled = string.IsNullOrEmpty(m_Text);

            if (m_TextComponent != null && IsInteractable())
            {
                if (m_WasCanceled)
                    text = m_OriginalText;

                SendOnSubmit();

                if (m_Keyboard != null)
                {
                    m_Keyboard.active = false;
                    m_Keyboard = null;
                }

                m_CaretPosition = m_CaretSelectPosition = 0;
                if (input != null)
                    input.imeCompositionMode = IMECompositionMode.Auto;
            }

            MarkGeometryAsDirty();
        }

        /// <summary>
        /// What to do when the event system sends a Deselect Event. Defaults to deactivating the inputfield.
        /// </summary>
        /// <param name="eventData">The data sent by the EventSystem</param>
        public override void OnDeselect(BaseEventData eventData)
        {
            DeactivateInputField();
            base.OnDeselect(eventData);
        }

        public virtual void OnSubmit(BaseEventData eventData)
        {
            if (!IsActive() || !IsInteractable())
                return;

            if (!isFocused)
                m_ShouldActivateNextUpdate = true;
        }

        private void EnforceContentType()
        {
            switch (contentType)
            {
                case ContentType.Standard:
                {
                    // Don't enforce line type for this content type.
                    m_InputType = InputType.Standard;
                    m_KeyboardType = TouchScreenKeyboardType.Default;
                    m_CharacterValidation = CharacterValidation.None;
                    break;
                }
                case ContentType.Autocorrected:
                {
                    // Don't enforce line type for this content type.
                    m_InputType = InputType.AutoCorrect;
                    m_KeyboardType = TouchScreenKeyboardType.Default;
                    m_CharacterValidation = CharacterValidation.None;
                    break;
                }
                case ContentType.IntegerNumber:
                {
                    m_LineType = LineType.SingleLine;
                    m_InputType = InputType.Standard;
                    m_KeyboardType = TouchScreenKeyboardType.NumberPad;
                    m_CharacterValidation = CharacterValidation.Integer;
                    break;
                }
                case ContentType.DecimalNumber:
                {
                    m_LineType = LineType.SingleLine;
                    m_InputType = InputType.Standard;
                    m_KeyboardType = TouchScreenKeyboardType.NumbersAndPunctuation;
                    m_CharacterValidation = CharacterValidation.Decimal;
                    break;
                }
                case ContentType.Alphanumeric:
                {
                    m_LineType = LineType.SingleLine;
                    m_InputType = InputType.Standard;
                    m_KeyboardType = TouchScreenKeyboardType.ASCIICapable;
                    m_CharacterValidation = CharacterValidation.Alphanumeric;
                    break;
                }
                case ContentType.Name:
                {
                    m_LineType = LineType.SingleLine;
                    m_InputType = InputType.Standard;
                    m_KeyboardType = TouchScreenKeyboardType.NamePhonePad;
                    m_CharacterValidation = CharacterValidation.Name;
                    break;
                }
                case ContentType.EmailAddress:
                {
                    m_LineType = LineType.SingleLine;
                    m_InputType = InputType.Standard;
                    m_KeyboardType = TouchScreenKeyboardType.EmailAddress;
                    m_CharacterValidation = CharacterValidation.EmailAddress;
                    break;
                }
                case ContentType.Password:
                {
                    m_LineType = LineType.SingleLine;
                    m_InputType = InputType.Password;
                    m_KeyboardType = TouchScreenKeyboardType.Default;
                    m_CharacterValidation = CharacterValidation.None;
                    break;
                }
                case ContentType.Pin:
                {
                    m_LineType = LineType.SingleLine;
                    m_InputType = InputType.Password;
                    m_KeyboardType = TouchScreenKeyboardType.NumberPad;
                    m_CharacterValidation = CharacterValidation.Integer;
                    break;
                }
                default:
                {
                    // Includes Custom type. Nothing should be enforced.
                    break;
                }
            }

            EnforceTextHOverflow();
        }

        void EnforceTextHOverflow()
        {
            if (m_TextComponent != null)
                if (multiLine)
                    m_TextComponent.horizontalOverflow = HorizontalWrapMode.Wrap;
                else
                    m_TextComponent.horizontalOverflow = HorizontalWrapMode.Overflow;
        }

        void SetToCustomIfContentTypeIsNot(params ContentType[] allowedContentTypes)
        {
            if (contentType == ContentType.Custom)
                return;

            for (int i = 0; i < allowedContentTypes.Length; i++)
                if (contentType == allowedContentTypes[i])
                    return;

            contentType = ContentType.Custom;
        }

        void SetToCustom()
        {
            if (contentType == ContentType.Custom)
                return;

            contentType = ContentType.Custom;
        }

        protected override void DoStateTransition(SelectionState state, bool instant)
        {
            if (m_HasDoneFocusTransition)
                state = SelectionState.Selected;
            else if (state == SelectionState.Pressed)
                m_HasDoneFocusTransition = true;

            base.DoStateTransition(state, instant);
        }

        /// <summary>
        /// See ILayoutElement.CalculateLayoutInputHorizontal.
        /// </summary>
        public virtual void CalculateLayoutInputHorizontal() {}

        /// <summary>
        /// See ILayoutElement.CalculateLayoutInputVertical.
        /// </summary>
        public virtual void CalculateLayoutInputVertical() {}

        /// <summary>
        /// See ILayoutElement.minWidth.
        /// </summary>
        public virtual float minWidth { get { return 0; } }

        /// <summary>
        /// Get the displayed with of all input characters.
        /// </summary>
        public virtual float preferredWidth
        {
            get
            {
                if (textComponent == null)
                    return 0;
                var settings = textComponent.GetGenerationSettings(Vector2.zero);
                return textComponent.cachedTextGeneratorForLayout.GetPreferredWidth(m_Text, settings) / textComponent.pixelsPerUnit;
            }
        }

        /// <summary>
        /// See ILayoutElement.flexibleWidth.
        /// </summary>
        public virtual float flexibleWidth { get { return -1; } }

        /// <summary>
        /// See ILayoutElement.minHeight.
        /// </summary>
        public virtual float minHeight { get { return 0; } }

        /// <summary>
        /// Get the height of all the text if constrained to the height of the RectTransform.
        /// </summary>
        public virtual float preferredHeight
        {
            get
            {
                if (textComponent == null)
                    return 0;
                var settings = textComponent.GetGenerationSettings(new Vector2(textComponent.rectTransform.rect.size.x, 0.0f));
                return textComponent.cachedTextGeneratorForLayout.GetPreferredHeight(m_Text, settings) / textComponent.pixelsPerUnit;
            }
        }

        /// <summary>
        /// See ILayoutElement.flexibleHeight.
        /// </summary>
        public virtual float flexibleHeight { get { return -1; } }

        /// <summary>
        /// See ILayoutElement.layoutPriority.
        /// </summary>
        public virtual int layoutPriority { get { return 1; } }
    }
}
