Bug #8773

Image is shown with random colors around if image is smaller than display area

Added by Marco Tedaldi over 7 years ago. Updated over 7 years ago.

Start date:
Due date:
% Done:


Estimated time:
Affected Version:
git development version
hardware architecture:


If an image is cropped in a way that is it smaller than the viewing area in dr mode (in 1:1 view) a border with almost random colors is visible around the image (see attached image).

To reproduce:
- Open image
- heavily crop (so that the resulting image is smaller than the viewing area in 1:1 view)
- completely zoom out (if not already done)
- close crop/rotate plugin
- enjoy the nice colors

Most probably several affected versions. Tested in 1.0+877~g3e8446e.

crop_rotate_1.0 877~g3e8446e.jpg (288 KB) crop_rotate_1.0 877~g3e8446e.jpg Screenshot showing the effect Marco Tedaldi, 06/12/2012 03:52 PM

Related issues

Has duplicate darktable - Bug #8682: cropping at max zoom level has weird artifactsDuplicate

Associated revisions

Revision 9619c930 (diff)
Added by Ulrich Pegelow over 7 years ago

allow scaled-up demosaic. this should fix #8773


#1 Updated by Tobias Ellinghaus over 7 years ago

  • Target version set to Candidate for next patch release
  • Status changed from New to Triaged
  • Category set to Darkroom

#2 Updated by Ulrich Pegelow over 7 years ago

  • % Done changed from 0 to 20


is the bug still present for you? I tried with your recipe and current git master without any issues.

#3 Updated by Tobias Ellinghaus over 7 years ago

I can still confirm the bug. I didn't have time to look into the code though.

#4 Updated by Edouard Gomez over 7 years ago

I think i may have fixed this bug with 17656b92b17ac3db80739dd3efca870488df1e83

Could you please test and report back as we seem to be unable to reproduce ourselves ?

#5 Updated by Edouard Gomez over 7 years ago

ah finally triggered the bug, crop box to its minimal size could trigger that colors bug. So my commit didn't help with this case.

I'll followup on this to clear if interpolation causes this, or crop, or interaction of both

#6 Updated by Edouard Gomez over 7 years ago

confirmed on 1.0.x branch. so new resampling code is not the cause for garbage.

do some of you know if this actually worked at a point not so old in darktable lifetime ? this could help me for bisecting the problem

#7 Updated by Michael Born over 7 years ago

I have the same issue with current git version.

example file:

crop the airplane and see for yourself.

I even got segfaults when opening/closing the crop&rotate module

#8 Updated by Ulrich Pegelow over 7 years ago

  • % Done changed from 20 to 100
  • Status changed from Triaged to Fixed

Should be fixed now in git master.

Reason for the bug was the fact that we did not allow up-scaling in demosaic. That was justified before integration of
our new interpolation code (bilinear, bicubic, ...) but now up-scaling is supported.

Fix was therefore easy. To be intensively checked: this has some potential to once again uncover hidden bugs in roi handling.

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