private IEnumerable<CanvasTextLayoutRegion> GetRegions(CanvasTextLayout tl, int idx, CanvasLineMetrics line, Range[] formatChanges)
{
var lineRange = new Range(idx, line.CharacterCount);
var inLineChanges = formatChanges.Where(i => lineRange.InterlappedWith(i)).ToArray();
if (inLineChanges.Length == 0)
{
var regs = tl.GetCharacterRegions(idx, line.CharacterCount);
foreach (var r in regs)
{
yield return r;
}
}
else
{
foreach (var p in inLineChanges)
{
var b = Math.Max(p.Begin, lineRange.Begin);
var e = Math.Min(p.End, lineRange.End);
var c = e - b + 1;
if (c > 0)
{
var regs = tl.GetCharacterRegions(b, c);
foreach (var r in regs)
{
yield return r;
}
}
}
}
}
