Transparent Images

[WM Developer]

Hi,
I can draw transparent images in a buffer and blit the final result out.
However,

I have a setup like this;

ChildComponent : Control {
// draws itself by override OnPaint() method useing Graphics.DrawImage() it
overlaps transparent images to make final image first by specifying
ImageAttributes to DrawImage()  method.
}

ParentComponent : COntrol {
ChildComponent child;
OnPaint() { /* draws images  */ }
}

Child control will overrite write ParentComponent screen because it is in
different context. However, If ChildComponent can copy the underlying image
of ParentComponent into buffer, it can draw it's images ontop of it and then
blit out with e.Graphics.DrawImage(0, 0, BackBuffer);

Problem, how do I scrape the image from underlying Parent component from
child image into BackBuffer? I only want the part that the child is
overlapping.

Help!

 

[Carsten Unterberg]

Hey,

by default, .Net Compact Framework don't support transparent images. When
you use Windows Mobile 5 or above, you can P/Invoke the Alphablend-Api.


[AlphaBlend]
http://msdn.microsoft.com/en-us/library/aa920812.aspx

[Alphablending with NETCF]
http://blogs.msdn.com/chrislorton/archive/2006/04/07/570649.aspx


Regards,

Carsten Unterberg | Test-Framework
http://test-framework.blogspot.com/

 

[A.Rocha]

Hi,

You can find here some controls to draw transparent images:

http://www.koushikdutta.com/search/label/WindowlessControls Tutorial