Serious Bug: GIF-File damaged by editing

[negg]

Hi!

I found a bug that damages GIF-Files when they are edited. Try this file:

http://www.aspekt1.net/ms/temp/testKilledByBlack.gif

Open it to edit, set Edit->Background Color to 255,255,255. Then select a small section in the upper half of the image and press DEL.

Something strange happens here: the area does NOT get white (as the background color is white this is what I would expect) but black!

But it gets worse: close the file, confirm save and overwrite, and reopen the file: The part of the image below the part you edited is gone! The file is damaged from that point.

Can anyone confirm this?

[xnview]

Sorry i can't reproduce this bug

[negg]

Ok, then our settings must be different maybe.

Do you get black color in the deleted area when you select white as background color?

[MiKiL]

Tested and happens. I only get black area when background colour is RGB (180,0,0).
Also noticed that corruption starts after the selected area ie. selection in center of the picture doesn't affect upperarea of the picture.
It appears to shift the pixels to right in those lines where selection was.

[Clo]

MiKil

Hello !

…It appears to shift the pixels to right in those lines where selection was.

• Hm… Something similar to THIS PROBLEM ?

KR
Claude
Clo

[MiKiL]

Pictures are more than 1000 words so screenshots this time.

Did same thing like negg except used Background color RGB(180,0,0).
Opened in edit -> Zoomed the picture 400% -> Selected area -> Pressed DEL (Black area appeared) ->
Closed file (with save overwriting) -> Opened file again to see that it's corrupted.

Before (Closing with save) screenshot:

After (Open picture again) screenshot:


Black area in Before-screenshot was the area I selected.

GIF write parameters:
Interlace [OFF]
Gif87a [ON]
Set transparency value... [OFF]

Hope this helps.

[xnview]

Yes with RGB(180, 0, 0) but not with RGB(255,255,255)