public Span GetSpan(Line line, string style)
{
var lineNumber = line.Number;
if (Start == End) return null;
if (lineNumber < Start.Line) return null;
if (lineNumber > End.Line) return null;
var columnStart = (lineNumber == Start.Line) ? Start.Column : 0;
var columnEnd = (lineNumber == End.Line) ? End.Column : line.Text.Length;
var selection = new Span(columnStart, columnEnd - columnStart,
style);
return selection;
}
public IEnumerable<Span> SplitWith(Span splitter)
{
if (!Intersects(splitter) || splitter.Length == 0)
{
yield return this;
yield break;
}
if (Start < splitter.Start)
yield return new Span(Start, splitter.Start - Start, Style);
yield return splitter;
if (End > splitter.End)
yield return new Span(splitter.End, End - splitter.End, Style);
}
void PaintSpan(Span span, float offset)
{
var style = styleProvider.GetStyle(span.Style);
if (style.background != null)
g.FillRectangle(style.background, offset, lineOffset, span.renderCache.Width, geometry.LineHeight);
g.DrawString(span.renderCache.Text, geometry.Font, style.foreground, offset, lineOffset, geometry.Format);
switch (style.decoration)
{
case Decoration.RedSquiggle:
PaintSquigglyUnderline(span, offset, Pens.Red);
break;
case Decoration.GreenSquiggle:
PaintSquigglyUnderline(span, offset, Pens.Green);
break;
case Decoration.BlueSquiggle:
PaintSquigglyUnderline(span, offset, Pens.Blue);
break;
}
}
void PaintSquigglyUnderline(Span span, float offset, Pen pen)
{
int dy = 1;
float bl = lineOffset + geometry.LineHeight - 2.0f;
for (var x = offset; x < offset + span.renderCache.Width; x += 2)
{
g.DrawLine(pen, x, bl + dy, x + 2, bl - dy);
dy = -dy;
}
}
public RenderCache(Span span, TextGeometry geometry, Line line, int charOffset)
{
Width = geometry.MeasureString(line.Text.Substring(span.Start, span.Length),
charOffset, out Text);
}
bool Intersects(Span other)
{
return End > other.Start && Start < other.End;
}
bool Engulfs(Span other)
{
return Start <= other.Start && End >= other.End;
}
IEnumerable<Span> ChopWith(Span other)
{
if (!Intersects(other))
yield return this;
else if (other.Engulfs(this))
yield return other;
else
{
if (Start < other.Start)
yield return ChopEnd(other.Start);
yield return other;
if (End > other.End)
yield return ChopStart(other.End);
}
}