Hi All,

I am currently evaluating the wpf drawing component, and I must say that I am impressed.

However, there is one thing, I am using diagram to create node A and node B. Node A has already done the transparency effect.

I want the diagram to be as transparent as node A. But at the moment I have not been able to do it.

Any assistance will be greatly appreciated.

Cheers,

Jack

I have tried many times. What is puzzling is that once the program is run, it then returns immediately after entering diagram_DrawForeground and does not respond to the diagram_NodeModifying event.. May I ask Lyubo, can you tell me your email account? I want to send you the project I'm working on now, help me see where it's done wrong, and wonder why I didn't make the diagram semi-transparent.
private void diagram_DrawForeground(object sender, DiagramEventArgs e)
{
if (overlayNode == null) // overlayNode is the smaller node in the diagram
return;
var graphics = e.Graphics;
var clip = new CombinedGeometry(
GeometryCombineMode.Exclude,
new RectangleGeometry(diagram.Bounds),
new RectangleGeometry(overlayNode.Bounds));

graphics.PushClip(clip);
graphics.DrawRectangle(new SolidColorBrush(Color.FromArgb(120, 200, 200, 200)), null, diagram.Bounds);
graphics.Pop();
}

private void diagram_NodeModifying(object sender, NodeValidationEventArgs e)
{
diagram.InvalidateForeground();
}

//private void diagram_DrawNode(object sender, DrawNodeEventArgs e)
//{
// if (e.Node != imageNode)
// return;

// var graphics = e.Graphics;
// var clip = new CombinedGeometry(
// GeometryCombineMode.Exclude,
// new RectangleGeometry(imageNode.Bounds),
// new RectangleGeometry(overlayNode.Bounds));
// var translate = new TranslateTransform(-imageNode.Bounds.X, -imageNode.Bounds.Y);
// graphics.PushTransform(translate);
// graphics.PushClip(clip);
// graphics.DrawRectangle(new SolidColorBrush(Color.FromArgb(120, 0, 0, 0)), null, imageNode.Bounds);
// graphics.Pop();
// graphics.Pop();
//}

Hello,

It appears you're creating your nodes at a later time. You need to invalidate the diagram's foreground after you've created your nodes, to trigger a repaint. Calling diagram.InvalidateForeground(); after creating your nodes will do that.

Regards,
Lyubo
MindFusion

Hello,

The foreground is invalidated by calling diagram.InvalidateForeground();. If you call it after creating your overlayNode, it will cause a repaint and apply the opacity mask as then overlayNode will not be null as was in your screenshot.

You can download a simple application that shows how to achieve this (and the requests from your several other threads) here: https://mindfusion.eu/_samples/ZoomExample.zip

Regards,
Lyubo
MindFusion