Odd problem with GIMP 3.0.8 Perspective Tool

[cjsmall]

I've noticed a strange new behavior with perspective transformation under GIMP 3 -- something I never saw using GIMP2.  Note that while I've seen this on multiple occasions, it does not occur every time I use the tool.  I am having trouble attaching images so I will provide URL links:

Here is an example picture:

Original Picture

Here the perspective tool is being used:

Using the Perspective Tool

And here is the result after applying the perspective transformation:

Results

Notice that after dragging the lower left corner to the left, the right edge of the image has now been deleted even though it was not touched.  As I said, I see this frequently but not always.  Is this a bug needing to be reported or is it the result of some new tool setting that has changed?  

Any help better understanding what is going on is appreciated.

[denzjos]

After using the perspective tool, you can use 'Image / Crop to Content' to remove the transparent part.
   

[Scallact]

This is definitely a bug, maybe try it in GIMP 3.2RC if you want to be sure it's not corrected already. And report the bug if you have time to do so.

[rich2005]

(02-20-2026, 10:00 PM)cjsmall Wrote: I've noticed a strange new behavior with perspective transformation under GIMP 3 -- something I never saw using GIMP2.  Note that while I've seen this on multiple occasions, it does not occur every time I use the tool. ......
..... snip .......or is it the result of some new tool setting that has changed?  

Finally managed to reproduce that.  (Not image offsets or crop leaving pixels...so...) 
Missing from your screenshots is the layers dock, but check that when you apply a curves correction you either check the Merge Filter option or if you leave that on, go to the layers dock and merge using the fx icon. Then apply the perspective tool.
A couple of screenshots here showing fx https://www.gimp-forum.net/Thread-Color-...1#pid46631
Definitely a bug.  I am sure cmyk-student will be interested.

   

Same effect using Gimp 3.2

[cjsmall]

Rich:

Thank you for your diligent effort in tracking down the source of the problem!  I previously got hit with the problem of filters not being shown during subsequent operations until someone pointed out the need to set the "Composite preview" option on various tools.  Now I see that the "Merge filter" option also must be set in order to avoid problem with other tools such as this perspective cropping.

As this is a real bug, I will report it.

denzjos, thanks for your comment regarding cropping the image.  The problem is that actual image content is missing where the transparency is shown, so that is not a viable solution.