Question

I am working with WPF DrawingVisual and Pen and encountered a problem.

When I draw a DrawingVisual with Pen, say, a Rectangle as follows:

Pen StrokePen = new Pen();
StrokePen.Brush = Brushes.SkyBlue;
StrokePen.Thickness = 6;

DrawingVisual dv = new DrawingVisual
DrawingContext dc = dv.RenderOpen();
dc.DrawingRectangle(......., StrokePen, ......);
dc.Close();

I found that the half of the Stroke cover the rectangle like the following:

Therefore, if the Thickness of the Pen is too large so that it even larger than the Rectangle, the Rectangle will disappear (The whole rectangle is covered by the Stroke).

Could I adjust some setting so that the Stroke (Pen) drawn on the rectangle will not cover the rectangle (only draw beyond the sides of the rectangle)

Thank you.

Answer 1

You could simply draw the Rectangle twice, first with a Pen, then with a Brush:

using (DrawingContext dc = dv.RenderOpen())
{
    ...
    dc.DrawingRectangle(null, StrokePen, ...); 
    dc.DrawingRectangle(FillBrush, null, ...);
    ....
}