public static VisualLineImageCache GetInstance()
{
if (_instance == null)
{
_instance = new VisualLineImageCache();
}
return(_instance);
}
public void Render(DrawingContext drawingContext, RenderContext renderContext)
{
// DrawingImage会自动Trimming，怎么解决这个问题？
#if false
DrawingImage cachedImg = VisualLineImageCache.GetInstance().GetCache(Document, Line);
DrawingGroup drawingGroup = null;
if (cachedImg == null)
{
renderContext.PrepareRendering();
drawingGroup = new DrawingGroup();
foreach (VisualLineElement elem in Elements)
{
var drawings = elem.GenerateDrawings(drawingContext, renderContext);
if (drawings != null)
{
foreach (var drawing in drawings)
{
drawingGroup.Children.Add(drawing);
}
}
}
cachedImg = new DrawingImage(drawingGroup);
VisualLineImageCache.GetInstance().AddCache(Document, Line, cachedImg);
renderContext.FinishRendering();
}
cachedImg.Freeze();
Point startPos = renderContext.Offset;
startPos.Y += (Owner.GlyphOption.LineHeight - cachedImg.Height);
drawingContext.DrawImage(cachedImg, new Rect(startPos, new Size(cachedImg.Width, cachedImg.Height)));
drawingContext.DrawDrawing(drawingGroup);
#else
renderContext.PrepareRendering();
foreach (VisualLineElement elem in Elements)
{
var drawings = elem.GenerateDrawings(drawingContext, renderContext);
if (drawings != null)
{
foreach (var drawing in drawings)
{
drawingContext.DrawDrawing(drawing);
}
}
}
renderContext.FinishRendering();
#endif
}
public void Dispose()
{
VisualLineImageCache.GetInstance().RemoveCache(Document, Line);
}