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Editing palette of transparent GIFs
Posted: Thu Aug 18, 2011 8:45 pm
by XnTriq
- Download and open 28jkub6.gif.
- Go to Image » Edit Palette... and double-click the third color (Index: 2).
- Change the value from R0/G170/B238 to any other color in the color picker and click OK.
- Image colors are all mixed up
Re: Editing palette of transparent GIFs
Posted: Tue Aug 23, 2011 3:07 pm
by marsh
Confirmed.
Re: Editing palette of transparent GIFs
Posted: Sat Sep 03, 2011 8:28 am
by DOS386
XnTriq wrote:[*]Image colors are all mixed up
FYI:
[1] The GIF is transparent, 3bpp (!!!), 3 unique colours from 8 (badly optimized), trans index ZERO, colour white ($FF,$FF,$FF)
[2] The GIF has a faulty ratio of 49
[3] Nothing is "mixed up", just the view is "broken", and only if transparency in XN is ON
Re: Editing palette of transparent GIFs
Posted: Sun Sep 04, 2011 7:00 am
by XnTriq
DOS386 wrote:FYI:
[1] The GIF is transparent, 3bpp (!!!), 3 unique colours from 8 (badly optimized), trans index ZERO, colour white ($FF,$FF,$FF)
[2] The GIF has a faulty ratio of 49
[3] Nothing is "mixed up", just the view is "broken", and only if transparency in XN is ON
FYI: Post #97684 is of tangential (!!!) if not ZERO relevance “in this” context
I know perfectly well how to optimize my GIFs.
28jkub6.gif is the result of an
experiment and was saved with XnView, which doesn't provide export to 2bpp.
The bug is reproducible at
any color depth.
Re: Editing palette of transparent GIFs
Posted: Sun Sep 04, 2011 2:59 pm
by DOS386
> Image colors are all mixed up
NO. Just the transparent index points to the color edited last time. How to fix? Remember the transparent index before editing the palette and set it back where it used to be.
> The bug is reproducible at any color depth.
Right. I had suspected the GIF to be "strange" ... but it's same for any transparent indexed color images, also PNG.
The problem is always there, but it's visible only if "view transparency" is ON.
PS: GIF ratio 49 is just a silly way to say "1" ... see formula in spec
32-bit (16m truecolor + alpha channel) PNG
2-bit (4 color palette) GIF
