GNOME Bugzilla – Bug 82353
lines on picture after resizing
Last modified: 2009-08-15 18:40:50 UTC
I am using a Gimp I try to resize a picture (make it smaller) I try to use different file extension jpg png. When I choose resize 30% of normal size I got 3 lines accros picture, this lines are saved to the picture, I try few other sizes, on 35% I had only one line very close to left side of picture on 25% resize I got clean picture. If you need to see this pic after resize pls contact me I will send you one.
Please make the picture available online and attach the URL to the bug-report. Alternatively you can attach the picture itself to the bug-report.
Created attachment 11016 [details] picture before rescale
Created attachment 11017 [details] picture after rescale
Your image contains many diagonal lines. What you are seeing when you resize the picture is the usual "moiré" effect that appears when you resample something that has a periodical pattern that does not match the resampling interval. In this case you see some darker lines, but you could also get any kind of strange patterns depending on how the pixels are laid out in the original image. I suggest that you change the type of interpolation that is performed by the GIMP when you rescale your images. Go to the Preferences dialog and in the section "Environment" change the setting of "Interpolation Type". Cubic interpolation gives the best results. Another option is to filter the image before scaling. You can use the Despeckle filter (<Image>->Filters->Enhance->Despeckle) or some of the blur filters. Anyway, this is not a GIMP bug but this is a consequence of rescaling an image that contains periodic features.
I'm having a similar problem. Open a blank 1682x1192 image, white background. Resolution: 72x72. RGB. When I scale this to 600x426 (enter 600 in Width and click OK) I get two grey lines on the left. Attaching result.
Created attachment 13485 [details] Erroneous image after Scale
By the way, I am using GIMP 1.2.3, by way of Debian unstable.
I can confirm this. Repeating the description with the dimensions of the original reporter (200x315 -> 150x236) I get these vertical lines on a completely white image too (at the same place). This seems to be independant of the vertical scaling factor.
Looks like a duplicate of bug 97187 (or vice versa).
*** This bug has been marked as a duplicate of 97187 ***
The fix for bug #104693 (and bug #97187) is part of the stable release 1.2.5. Closing this bug.