// Copyright (c) 2014 AlphaSierraPapa for the SharpDevelop Team
//
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated documentation files (the "Software"), to deal in the Software
// without restriction, including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
using System;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using Unity.CodeEditor.Document;
using Unity.CodeEditor.Text;
using UnityEngine;
using LogicalDirection = Unity.CodeEditor.Document.LogicalDirection;
namespace Unity.CodeEditor.Rendering
{
/// <summary>
/// Represents a visual element in the document.
/// </summary>
internal abstract class VisualLineElement
{
/// <summary>
/// Creates a new VisualLineElement.
/// </summary>
/// <param name="visualLength">The length of the element in VisualLine coordinates. Must be positive.</param>
/// <param name="documentLength">The length of the element in the document. Must be non-negative.</param>
protected VisualLineElement(int visualLength, int documentLength)
{
if (visualLength < 1)
throw new ArgumentOutOfRangeException(nameof(visualLength), visualLength, "Value must be at least 1");
if (documentLength < 0)
throw new ArgumentOutOfRangeException(nameof(documentLength), documentLength, "Value must be at least 0");
VisualLength = visualLength;
DocumentLength = documentLength;
}
/// <summary>
/// Gets the length of this element in visual columns.
/// </summary>
internal int VisualLength { get; private set; }
/// <summary>
/// Gets the length of this element in the text document.
/// </summary>
internal int DocumentLength { get; private set; }
/// <summary>
/// Gets the visual column where this element starts.
/// </summary>
[SuppressMessage("Microsoft.Naming", "CA1721:PropertyNamesShouldNotMatchGetMethods",
Justification = "This property holds the start visual column, use GetVisualColumn to get inner visual columns.")]
internal int VisualColumn { get; set; }
/// <summary>
/// Gets the text offset where this element starts, relative to the start text offset of the visual line.
/// </summary>
internal int RelativeTextOffset { get; set; }
/// <summary>
/// Gets the text run properties.
/// A unique <see cref="VisualLineElementTextRunProperties"/> instance is used for each
/// <see cref="VisualLineElement"/>; colorizing code may assume that modifying the
/// <see cref="VisualLineElementTextRunProperties"/> will affect only this
/// <see cref="VisualLineElement"/>.
/// </summary>
internal TextParagraphProperties TextParagraphProperties { get; private set; }
/// <summary>
/// Gets/sets the brush used for the background of this <see cref="VisualLineElement" />.
/// </summary>
internal Color BackgroundColor { get; set; }
internal void SetTextParagraphProperties(TextParagraphProperties p)
{
TextParagraphProperties = p;
}
/// <summary>
/// Creates the TextRun for this line element.
/// </summary>
/// <param name="startVisualColumn">
/// The visual column from which the run should be constructed.
/// Normally the same value as the <see cref="VisualColumn"/> property is used to construct the full run;
/// but when word-wrapping is active, partial runs might be created.
/// </param>
/// <param name="context">
/// Context object that contains information relevant for text run creation.
/// </param>
internal abstract TextRun CreateTextRun(int startVisualColumn, ITextRunConstructionContext context);
/// <summary>
/// Retrieves the text span immediately before the visual column.
/// </summary>
/// <remarks>This method is used for word-wrapping in bidirectional text.</remarks>
internal virtual ReadOnlyMemory<char> GetPrecedingText(int visualColumnLimit, ITextRunConstructionContext context)
{
return ReadOnlyMemory<char>.Empty;
}
/// <summary>
/// Gets if this VisualLineElement can be split.
/// </summary>
internal virtual bool CanSplit => false;
/// <summary>
/// Splits the element.
/// </summary>
/// <param name="splitVisualColumn">Position inside this element at which it should be broken</param>
/// <param name="elements">The collection of line elements</param>
/// <param name="elementIndex">The index at which this element is in the elements list.</param>
internal virtual void Split(int splitVisualColumn, IList<VisualLineElement> elements, int elementIndex)
{
throw new NotSupportedException();
}
/// <summary>
/// Helper method for splitting this line element into two, correctly updating the
/// <see cref="VisualLength"/>, <see cref="DocumentLength"/>, <see cref="VisualColumn"/>
/// and <see cref="RelativeTextOffset"/> properties.
/// </summary>
/// <param name="firstPart">The element before the split position.</param>
/// <param name="secondPart">The element after the split position.</param>
/// <param name="splitVisualColumn">The split position as visual column.</param>
/// <param name="splitRelativeTextOffset">The split position as text offset.</param>
protected void SplitHelper(VisualLineElement firstPart, VisualLineElement secondPart, int splitVisualColumn, int splitRelativeTextOffset)
{
if (firstPart == null)
throw new ArgumentNullException(nameof(firstPart));
if (secondPart == null)
throw new ArgumentNullException(nameof(secondPart));
var relativeSplitVisualColumn = splitVisualColumn - VisualColumn;
var relativeSplitRelativeTextOffset = splitRelativeTextOffset - RelativeTextOffset;
if (relativeSplitVisualColumn <= 0 || relativeSplitVisualColumn >= VisualLength)
throw new ArgumentOutOfRangeException(nameof(splitVisualColumn), splitVisualColumn, "Value must be between " + (VisualColumn + 1) + " and " + (VisualColumn + VisualLength - 1));
if (relativeSplitRelativeTextOffset < 0 || relativeSplitRelativeTextOffset > DocumentLength)
throw new ArgumentOutOfRangeException(nameof(splitRelativeTextOffset), splitRelativeTextOffset, "Value must be between " + (RelativeTextOffset) + " and " + (RelativeTextOffset + DocumentLength));
var oldVisualLength = VisualLength;
var oldDocumentLength = DocumentLength;
var oldVisualColumn = VisualColumn;
var oldRelativeTextOffset = RelativeTextOffset;
firstPart.VisualColumn = oldVisualColumn;
secondPart.VisualColumn = oldVisualColumn + relativeSplitVisualColumn;
firstPart.RelativeTextOffset = oldRelativeTextOffset;
secondPart.RelativeTextOffset = oldRelativeTextOffset + relativeSplitRelativeTextOffset;
firstPart.VisualLength = relativeSplitVisualColumn;
secondPart.VisualLength = oldVisualLength - relativeSplitVisualColumn;
firstPart.DocumentLength = relativeSplitRelativeTextOffset;
secondPart.DocumentLength = oldDocumentLength - relativeSplitRelativeTextOffset;
if (firstPart.TextParagraphProperties == null)
firstPart.TextParagraphProperties = TextParagraphProperties.Clone();
if (secondPart.TextParagraphProperties == null)
secondPart.TextParagraphProperties = TextParagraphProperties.Clone();
firstPart.BackgroundColor = BackgroundColor;
secondPart.BackgroundColor = BackgroundColor;
}
/// <summary>
/// Gets the visual column of a text location inside this element.
/// The text offset is given relative to the visual line start.
/// </summary>
internal virtual int GetVisualColumn(int relativeTextOffset)
{
if (relativeTextOffset >= RelativeTextOffset + DocumentLength)
return VisualColumn + VisualLength;
return VisualColumn;
}
/// <summary>
/// Gets the text offset of a visual column inside this element.
/// </summary>
/// <returns>A text offset relative to the visual line start.</returns>
internal virtual int GetRelativeOffset(int visualColumn)
{
if (visualColumn >= VisualColumn + VisualLength)
return RelativeTextOffset + DocumentLength;
return RelativeTextOffset;
}
/// <summary>
/// Gets the next caret position inside this element.
/// </summary>
/// <param name="visualColumn">The visual column from which the search should be started.</param>
/// <param name="direction">The search direction (forwards or backwards).</param>
/// <param name="mode">Whether to stop only at word borders.</param>
/// <returns>The visual column of the next caret position, or -1 if there is no next caret position.</returns>
/// <remarks>
/// In the space between two line elements, it is sufficient that one of them contains a caret position;
/// though in many cases, both of them contain one.
/// </remarks>
internal virtual int GetNextCaretPosition(int visualColumn, LogicalDirection direction, CaretPositioningMode mode)
{
var stop1 = VisualColumn;
var stop2 = VisualColumn + VisualLength;
if (direction == LogicalDirection.Backward)
{
if (visualColumn > stop2 && mode != CaretPositioningMode.WordStart && mode != CaretPositioningMode.WordStartOrSymbol)
return stop2;
if (visualColumn > stop1)
return stop1;
} else
{
if (visualColumn < stop1)
return stop1;
if (visualColumn < stop2 && mode != CaretPositioningMode.WordStart && mode != CaretPositioningMode.WordStartOrSymbol)
return stop2;
}
return -1;
}
/// <summary>
/// Gets whether the specified offset in this element is considered whitespace.
/// </summary>
internal virtual bool IsWhitespace(int visualColumn)
{
return false;
}
/// <summary>
/// Gets whether the <see cref="GetNextCaretPosition"/> implementation handles line borders.
/// If this property returns false, the caller of GetNextCaretPosition should handle the line
/// borders (i.e. place caret stops at the start and end of the line).
/// This property has an effect only for VisualLineElements that are at the start or end of a
/// <see cref="VisualLine"/>.
/// </summary>
internal virtual bool HandlesLineBorders => false;
/*
/// <summary>
/// Queries the cursor over the visual line element.
/// </summary>
protected internal virtual void OnQueryCursor(PointerEventArgs e)
{
}*/
/// <summary>
/// Allows the visual line element to handle a pointer event.
/// </summary>
protected internal virtual void OnPointerPressed(Vector2 localPosition)
{
}
/// <summary>
/// Allows the visual line element to handle a pointer event.
/// </summary>
protected internal virtual void OnPointerReleased(Vector2 localPosition)
{
}
}
}