Hello!

We have such diagramming tasks that require node semi-transparency and graying a node (e.g. show node as disabled).

How could I do that?
1. I have no idea how to rich transparency.
2. I think that I could gray a node with CustomDraw – just overlay a gray rectangle over the node in additional mode. Am I right or there are more elegant way to do that?

Thank you in advance!
Best wishes,
Vladimir.

OK. I see.
Thank you for your post.

What about grayed node (not transparent)?
Please look at the right node on the picture labeled "Grayed". It's not transparent.
How to do that?

One addition - GetConcaveHull returns the points in SVG coordinates, which you will need to map to the node's bounding rectangle as shown below.

node.CustomDraw = CustomDraw.Additional;
.....

private System.Drawing.SolidBrush grayBrush =
	new System.Drawing.SolidBrush(Color.FromArgb(100, Color.Gray));

private void diagram_DrawNode(object sender, DrawNodeEventArgs e)
{
	SvgNode svgNode = e.Node as SvgNode;
	if (svgNode != null && !e.Shadow)
	{
		PointF[] points = svgNode.Content.GetConcaveHull();

		GraphicsState gs = e.Graphics.Save();
		MapCoordinateSystem(e.Graphics,
			svgNode.Content.GetBounds(), e.Node.Bounds);
		e.Graphics.FillPolygon(grayBrush, points);
		e.Graphics.Restore(gs);
    }
}

private void MapCoordinateSystem(IGraphics graphics,
	RectangleF newBounds, RectangleF oldBounds)
{
	graphics.TranslateTransform(oldBounds.X, oldBounds.Y);
	graphics.ScaleTransform(
		oldBounds.Width / newBounds.Width,
		oldBounds.Height / newBounds.Height);
	graphics.TranslateTransform(-newBounds.X, -newBounds.Y);
} 

The code above assumes you are using ContentAlign=Stretch. Since GetConcaveHull() isn't very fast, you might want to cache the points for each SvgContent in some Dictionary.

I hope that helps,
Stoyan