void UpdateLineLayout(bool invalidateAll)
{
if (this.canvas == null)
{
// Not yet... no template
return;
}
// Determine number of visible lines
this.VisibleLineCount = (int)Math.Ceiling(this.canvas.ActualHeight / this.lineHeight);
this.VerticalScrollPageSize = this.VisibleLineCount - 1;
this.VerticalScrollRange = this.Buffer.TextData.Lines.Count;
var lineNumbers = this.displayedLines.Keys.ToArray();
List<TextLineVisual> recycledLines = null;
// Remove any line not in visible range
if (invalidateAll)
{
// Put all currently displayed lines in the recycle bin
recycledLines = this.displayedLines.Values.ToList();
this.displayedLines.Clear();
}
else
{
foreach (var line in lineNumbers)
{
if (line < this.TopVisibleLine || line >= this.TopVisibleLine + this.VisibleLineCount)
{
// Put the line in the recycle bin, leaving it parented by the canvas. This
// greatly reduces visual tree noise.
if (recycledLines == null)
{
recycledLines = new List<TextLineVisual>();
}
recycledLines.Add(this.displayedLines[line]);
this.displayedLines.Remove(line);
}
}
}
// Now update and position each line.
for (int i = 0; i < this.VisibleLineCount && i + this.TopVisibleLine < this.Buffer.TextData.Lines.Count; i++)
{
int lineIndex = i + this.TopVisibleLine;
TextLineVisual visual;
if (!this.displayedLines.TryGetValue(lineIndex, out visual))
{
if (recycledLines != null && recycledLines.Count > 0)
{
visual = recycledLines[recycledLines.Count - 1];
recycledLines.RemoveAt(recycledLines.Count - 1);
visual.SetLineIndex(lineIndex);
}
else
{
visual = new TextLineVisual(this, lineIndex);
visual.SetBinding(Canvas.LeftProperty, this.horizontalOffsetBinding);
this.canvas.Children.Add(visual);
}
this.displayedLines[lineIndex] = visual;
}
Canvas.SetTop(visual, i * this.lineHeight);
}
// Remove any remaining lines in the recycle bin
if (recycledLines != null)
{
foreach (var visual in recycledLines)
{
this.canvas.Children.Remove(visual);
}
}
PlaceCaretAndSelection();
}
TextLineVisual GetLineVisual(int line)
{
TextLineVisual visual;
if (!this.displayedLines.TryGetValue(line, out visual))
{
// Note: This will not be displayed and will just GC away when
// the caller is done with it. Still useful for coord/loc mapping.
visual = new TextLineVisual(this, line);
}
return visual;
}
