static void SetupContextForDrawing(CGContext ctx)
{
if (ctx.IsPathEmpty ())
return;
// setup pattern drawing to better match the behavior of Cairo
var drawPoint = ctx.GetCTM ().TransformPoint (ctx.GetPathBoundingBox ().Location);
var patternPhase = new SizeF (drawPoint.X, drawPoint.Y);
if (patternPhase != SizeF.Empty)
ctx.SetPatternPhase (patternPhase);
}
