// Copyright (c) AlphaSierraPapa for the SharpDevelop Team (for details please see \doc\copyright.txt)
// This code is distributed under the GNU LGPL (for details please see \doc\license.txt)
using System;
using System.Collections.Generic;
using System.Windows.Documents;
using System.Windows.Media.TextFormatting;
using ICSharpCode.AvalonEdit.Document;
using ICSharpCode.AvalonEdit.Utils;
namespace ICSharpCode.AvalonEdit.Rendering
{
/// <summary>
/// VisualLineElement that represents a piece of text.
/// </summary>
public class VisualLineText : VisualLineElement
{
VisualLine parentVisualLine;
/// <summary>
/// Gets the parent visual line.
/// </summary>
public VisualLine ParentVisualLine {
get { return parentVisualLine; }
}
/// <summary>
/// Creates a visual line text element with the specified length.
/// It uses the <see cref="ITextRunConstructionContext.VisualLine"/> and its
/// <see cref="VisualLineElement.RelativeTextOffset"/> to find the actual text string.
/// </summary>
public VisualLineText(VisualLine parentVisualLine, int length) : base(length, length)
{
if (parentVisualLine == null)
throw new ArgumentNullException("parentVisualLine");
this.parentVisualLine = parentVisualLine;
}
/// <summary>
/// Override this method to control the type of new VisualLineText instances when
/// the visual line is split due to syntax highlighting.
/// </summary>
protected virtual VisualLineText CreateInstance(int length)
{
return new VisualLineText(parentVisualLine, length);
}
/// <inheritdoc/>
public override TextRun CreateTextRun(int startVisualColumn, ITextRunConstructionContext context)
{
if (context == null)
throw new ArgumentNullException("context");
int relativeOffset = startVisualColumn - VisualColumn;
StringSegment text = context.GetText(context.VisualLine.FirstDocumentLine.Offset + RelativeTextOffset + relativeOffset, DocumentLength - relativeOffset);
return new TextCharacters(text.Text, text.Offset, text.Count, this.TextRunProperties);
}
/// <inheritdoc/>
public override bool IsWhitespace(int visualColumn)
{
int offset = visualColumn - this.VisualColumn + parentVisualLine.FirstDocumentLine.Offset + this.RelativeTextOffset;
return char.IsWhiteSpace(parentVisualLine.Document.GetCharAt(offset));
}
/// <inheritdoc/>
public override TextSpan<CultureSpecificCharacterBufferRange> GetPrecedingText(int visualColumnLimit, ITextRunConstructionContext context)
{
if (context == null)
throw new ArgumentNullException("context");
int relativeOffset = visualColumnLimit - VisualColumn;
StringSegment text = context.GetText(context.VisualLine.FirstDocumentLine.Offset + RelativeTextOffset, relativeOffset);
CharacterBufferRange range = new CharacterBufferRange(text.Text, text.Offset, text.Count);
return new TextSpan<CultureSpecificCharacterBufferRange>(range.Length, new CultureSpecificCharacterBufferRange(this.TextRunProperties.CultureInfo, range));
}
/// <inheritdoc/>
public override bool CanSplit {
get { return true; }
}
/// <inheritdoc/>
public override void Split(int splitVisualColumn, IList<VisualLineElement> elements, int elementIndex)
{
if (splitVisualColumn <= VisualColumn || splitVisualColumn >= VisualColumn + VisualLength)
throw new ArgumentOutOfRangeException("splitVisualColumn", splitVisualColumn, "Value must be between " + (VisualColumn + 1) + " and " + (VisualColumn + VisualLength - 1));
if (elements == null)
throw new ArgumentNullException("elements");
if (elements[elementIndex] != this)
throw new ArgumentException("Invalid elementIndex - couldn't find this element at the index");
int relativeSplitPos = splitVisualColumn - VisualColumn;
VisualLineText splitPart = CreateInstance(DocumentLength - relativeSplitPos);
SplitHelper(this, splitPart, splitVisualColumn, relativeSplitPos + RelativeTextOffset);
elements.Insert(elementIndex + 1, splitPart);
}
/// <inheritdoc/>
public override int GetRelativeOffset(int visualColumn)
{
return this.RelativeTextOffset + visualColumn - this.VisualColumn;
}
/// <inheritdoc/>
public override int GetVisualColumn(int relativeTextOffset)
{
return this.VisualColumn + relativeTextOffset - this.RelativeTextOffset;
}
/// <inheritdoc/>
public override int GetNextCaretPosition(int visualColumn, LogicalDirection direction, CaretPositioningMode mode)
{
int textOffset = parentVisualLine.StartOffset + this.RelativeTextOffset;
int pos = TextUtilities.GetNextCaretPosition(parentVisualLine.Document, textOffset + visualColumn - this.VisualColumn, direction, mode);
if (pos < textOffset || pos > textOffset + this.DocumentLength)
return -1;
else
return this.VisualColumn + pos - textOffset;
}
}
}