void DrawCanvas()
{
if (canvas == null)
{
return;
}
var updates = new List <Rectangle>();
canvas.GraphDefaults(updates);
canvas.SetColor(handler.Foreground);
canvas.SetLineStyle(BGICanvas.LineStyle.User, this.LinePattern, 1);
canvas.Line(20, 20, 108, 20, updates);
canvas.Line(20, 20, 108, 64, updates);
canvas.Line(20, 20, 108, 108, updates);
canvas.Line(20, 20, 64, 108, updates);
canvas.Line(20, 20, 20, 108, updates);
canvas.SetLineStyle(BGICanvas.LineStyle.User, this.LinePattern, 3);
canvas.Line(236, 20, 148, 20, updates);
canvas.Line(236, 20, 148, 64, updates);
canvas.Line(236, 20, 148, 108, updates);
canvas.Line(236, 20, 192, 108, updates);
canvas.Line(236, 20, 236, 108, updates);
canvas.Control.Invalidate();
}