After an evaluation, GNOME has moved from Bugzilla to GitLab. Learn more about GitLab.
No new issues can be reported in GNOME Bugzilla anymore.
To report an issue in a GNOME project, go to GNOME GitLab.
Do not go to GNOME Gitlab for: Bluefish, Doxygen, GnuCash, GStreamer, java-gnome, LDTP, NetworkManager, Tomboy.
Bug 674398 - Incorrect open BMP-file
Incorrect open BMP-file
Status: RESOLVED DUPLICATE of bug 573090
Product: GIMP
Classification: Other
Component: Data
2.8.0
Other All
: Normal normal
: 2.8
Assigned To: GIMP Bugs
GIMP Bugs
Depends on:
Blocks:
 
 
Reported: 2012-04-19 15:05 UTC by Nikolay Keskinov - AMEKA
Modified: 2013-10-13 07:04 UTC
See Also:
GNOME target: ---
GNOME version: ---


Description Nikolay Keskinov - AMEKA 2012-04-19 15:05:11 UTC 
The file "Gimp-Open-Bug.bmp" in Windows and Fax Viewer looks OK,
but GIMP opens only parts of image.

Nikolay Keskinov
Comment 1 Nikolay Keskinov - AMEKA 2012-04-19 15:34:37 UTC 
http://www.otel.net/~ameka/pub/gimp/Gimp-Open-Bug.bmp
Comment 2 Michael Schumacher 2012-04-19 15:54:15 UTC 
The BMP file has an alpha channel, and the parts that are not shown are fully transparent.
Comment 3 Mike Henning (drawoc) 2012-04-22 03:30:22 UTC 
Since this file uses a BITMAPINFOHEADER, 32 bpp, and BI_RGB as the format, according to wikipedia the image actually doesn't have an alpha channel - the format should be X8 B8 G8 R8, (last byte just thrown out). It looks like this is what Firefox and gpicview assume.

What complicates this is some programs (including the gimp, if color profile information is disabled in the export dialog) store the alpha channel of images in the extra (supposedly unused) byte of a BITMAPINFOHEADER image. There's no good reason to make a 32 bpp image instead of a 24 bpp if the last byte never matters, so the spec isn't really that smart here.

This was fixed with headers BITMAPV3INFOHEADER and above, where the bit masks make things clear.

It's not really clear what should happen when a bitmap like this is opened. It might be best to give the user a choice as to whether to ignore the alpha channel or not.
Comment 4 Michael Schumacher 2012-05-28 10:57:09 UTC 
Does this still happen with 2.8.0?
Comment 5 Mike Henning (drawoc) 2012-05-28 14:27:11 UTC 
Yes, it happens with both 2.8 and also master.

Constructing a GEGL graph with only a gegl:load does load this file without the alpha chanel, although that's just falling back to gegl:magick-load.
Comment 6 Mukund Sivaraman 2012-10-08 03:49:40 UTC 
Resolving this as a duplicate of bug #573090.

*** This bug has been marked as a duplicate of bug 573090 ***
Comment 7 Nikolay Keskinov - AMEKA 2013-10-13 07:04:05 UTC 
Thank you for correction in version gimp-2.8.6
I understand that the wrong is not in GIMP, but I can not change my BMP generator (It is EasyBuilder8000 terminal emulator from www.weintek.com)

THANK YOU VERY MUCH !

Nikolay Keskinov