[32] Lister's canvas doesn't refresh with some animated GIFs

[CJ Flash]

Here's the screenshot: http://www.imagebam.com/image/3cfcd2151729266
Link to original file: http://www.imagebam.com/image/913ae6151728916

This bug is reproduced in all betas of TC 8.0 x32. As MVV suggested on russian forum, making of double bufferization can help in this case and also with flickering.

[ghisler(Author)]

Confirmed with 32-bit only, thanks. The problem is that TC doesn't clear the background to avoid flickering, but the image seems to contain transparent parts...

[MVV]

Both x32 and x64 TC have problems here:
x32: fast drawing w/o flickering, but problems with transparent animations,
x64: drawing with erasing and MEGA flickering, but transparent animations are drawn correctly (example)

Christian, is it hard to realize double-buffering here? I mean that:
1. You fill TBitmap in memory with lister background color,
2. You draw needed frame onto that bitmap
3. You copy entire bitmap contents to lister window
4. Repeat from step 1 with next frame after delay
You DON'T need to erase Lister window in that case (I mean that window part where you draw bitmap), just draw bitmap over! And you won't see any flickering or overlays.

[ghisler(Author)]

Well, I could try that, but it would require twice the memory.

[MVV]

It will require only additional memory block for one frame (w*h*depth bytes), so it won't be critical on modern systems. BTW maybe some Delphi component already supports DB? (maybe some timage or something similar.) And, you may add an INI option to disable DB for users who want to see flickering.

[ghisler(Author)]

I have added this now to beta 4, please let me know what you think!

[CJ Flash]

2ghisler(Author)
Bug with animation of transparent GIFs is gone, thanks!

[Flint]

Confirm the bug and fix.

[ghisler(Author)]

Thanks!

[MVV]

Christian, have you implemented double buffering? It looks perfectly.

[ghisler(Author)]

Yes I have!