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// 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.Linq;
using ICSharpCode.AvalonEdit.Document;
namespace ICSharpCode.AvalonEdit.Rendering
{
/// <summary>
/// Base class for <see cref="IVisualLineTransformer"/> that helps
/// colorizing the document. Derived classes can work with document lines
/// and text offsets and this class takes care of the visual lines and visual columns.
/// </summary>
public abstract class DocumentColorizingTransformer : ColorizingTransformer
{
DocumentLine currentDocumentLine;
int firstLineStart;
int currentDocumentLineStartOffset, currentDocumentLineEndOffset;
/// <summary>
/// Gets the current ITextRunConstructionContext.
/// </summary>
protected ITextRunConstructionContext CurrentContext { get; private set; }
/// <inheritdoc/>
protected override void Colorize(ITextRunConstructionContext context)
{
if (context == null)
throw new ArgumentNullException("context");
this.CurrentContext = context;
currentDocumentLine = context.VisualLine.FirstDocumentLine;
firstLineStart = currentDocumentLineStartOffset = currentDocumentLine.Offset;
currentDocumentLineEndOffset = currentDocumentLineStartOffset + currentDocumentLine.Length;
if (context.VisualLine.FirstDocumentLine == context.VisualLine.LastDocumentLine) {
ColorizeLine(currentDocumentLine);
} else {
ColorizeLine(currentDocumentLine);
// ColorizeLine modifies the visual line elements, loop through a copy of the line elements
foreach (VisualLineElement e in context.VisualLine.Elements.ToArray()) {
int elementOffset = firstLineStart + e.RelativeTextOffset;
if (elementOffset >= currentDocumentLineEndOffset) {
currentDocumentLine = context.Document.GetLineByOffset(elementOffset);
currentDocumentLineStartOffset = currentDocumentLine.Offset;
currentDocumentLineEndOffset = currentDocumentLineStartOffset + currentDocumentLine.Length;
ColorizeLine(currentDocumentLine);
}
}
}
currentDocumentLine = null;
this.CurrentContext = null;
}
/// <summary>
/// Override this method to colorize an individual document line.
/// </summary>
protected abstract void ColorizeLine(DocumentLine line);
/// <summary>
/// Changes a part of the current document line.
/// </summary>
/// <param name="startOffset">Start offset of the region to change</param>
/// <param name="endOffset">End offset of the region to change</param>
/// <param name="action">Action that changes an individual <see cref="VisualLineElement"/>.</param>
protected void ChangeLinePart(int startOffset, int endOffset, Action<VisualLineElement> action)
{
if (startOffset < currentDocumentLineStartOffset || startOffset > currentDocumentLineEndOffset)
throw new ArgumentOutOfRangeException("startOffset", startOffset, "Value must be between " + currentDocumentLineStartOffset + " and " + currentDocumentLineEndOffset);
if (endOffset < startOffset || endOffset > currentDocumentLineEndOffset)
throw new ArgumentOutOfRangeException("endOffset", endOffset, "Value must be between " + startOffset + " and " + currentDocumentLineEndOffset);
VisualLine vl = this.CurrentContext.VisualLine;
int visualStart = vl.GetVisualColumn(startOffset - firstLineStart);
int visualEnd = vl.GetVisualColumn(endOffset - firstLineStart);
if (visualStart < visualEnd) {
ChangeVisualElements(visualStart, visualEnd, action);
}
}
}
}
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