Delphi XE2: How to draw transparent GIF images on toolbar using TImageList

0
votes

Using: Delphi XE2; VCL Forms application

Is it possible to draw transparent GIF images on an ActionToolbar (with ActionManager) using TImageList?

I have been trying but what I get is a black background on the toolbuttons.

The GIF images are 256 colors; and have transparency (verified by opening the images in Corel PaintShopPro).

On the ImageList, I have set the properties:

ColorDepth := cd32bit, DrawingStyle := dsTransparent.

Screen captures of the form at design-time and run-time:

enter image description here

enter image description here

Any tips or workaround is appreciated!

1
delphitransparencytoolbargiftimagelist
Isn't this the bottom-left-pixel thing? delphi.about.com/od/delphitips2007/qt/timage_transp.htm In that case the transparent color is defined differently (pixel vs. palette index), so you'll have to match those. – Jan Doggen
cd32bit is wrong, as is dsTransparent. There's no alpha channel here. FWIW, GIF is the wrong format for these images. You want 32bpp with alpha channel. – David Heffernan
@JanDoggen: Excellent! This works. – Steve F
@DavidHeffernan: Yes. I have corrected to cd8Bit. But not sure about the alpha channel. Where is the property setting for that? – Steve F
A GIF does not have an alpha channel. You should stop using GIF if you want to have good transparency. – David Heffernan

1 Answers

1
votes

Save your GIF as PNG. The PNG has alpha channel and supports semi transparency