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Strange results from cropping (looks like a bug)
#1
This problem first arose when I upgraded from GIMP 2.10.18 to GIMP 2.10.24 but I now find also exists in GIMP 2.10.28, which in this case is being run on Windows.

I'm NOT confidant when it comes to proper terminology for describing what happens.  Therefore, I've produced some screenshots that display what I'd call the first sign of a problem.  Start by opening an image file using GIMP 2.10.18.  Then crop the image.  The attached file named G21018cropped.jpg (maybe 1 of 4) displays the result, which is what I've always been accustomed to when using GIMP (i.e., GOOD result).  Now do the same thing using GIMP 2.10.28.  The attached file named G21028cropped.jpg (2 of 4) displays what I call a strange result (i.e., BAD).

Notice the difference in the yellow dashed rectangle (whatever that might be called).  In the GOOD case it corresponds to the size/shape of the new image produced by the crop operation.  In the BAD case I'm NOT sure exactly what it corresponds to but my guess is that it is the size/shape of the original image before cropping.

If you look at things like Image>Canvas Size, Image>Print Size, Image>Scale Image what is displayed in the number of pixels in the cropped image.  In that, GOOD and BAD are the same.  However, I commonly add a Background Layer to my photos which fit the size of the paper intended for printing and provide a border of my choosing which means preferred color and some times includes text.

To add such a background involves creating a new/larger layer which is offset in such manner that it surrounds the image/photo/picture.  I typically add a transparent layer after which it becomes necessary to use the Image>Fit Canvas To Layers operation in order to fill that layer with a background color.  That is when the strange/BAD results first appear as shown in the attached file named G21028error.jpg (3 of 4).  If you perform Image>Canvas Size the height is what was expected but the width does NOT correspond to anything recognizable.  Note: when the crop was performed in this case the height was NOT changed.  My guess is that if it had been changed the same unpredictable result may have occurred for the height as well.  The file named G21018desired.jpg (4 of 4) shows the desired/intended result.

The only difference between the GOOD and BAD scenario is the version of GIMP being used.  While the same investigation was NOT performed on GIMP 2.10.24, recollection is that the same thing happened but it was easy to revert to using the older version of GIMP thinking this problem would get resolved going forward.  However, that did NOT happen for GIMP 2.10.28 so it was decided to report the problem.


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#2
Have you set your crop tool to delete the cropped pixels?
(There is anew feature since ? to delete /just not show those pixels)
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#3
I must admit I got lost off with the GOOD and the BAD, however

When posting screenshots of issues include the tool options and layers in the images. So many things in your work flow affect the result. Crop with allow growing on or off. Crop with delete cropped pixels on or off. Canvas size with width / height linked not linked. Size of the layers (obviously different as shot 1 & 2 are single layer 3 & 4 are two layers)

I can get #4 easily with the Image -> Canvas size by adding to the initial values or multiplying factor to the initial values depending on what I want. Uniform size border or retain aspect ratio.
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#4
(10-07-2021, 05:23 PM)nelo Wrote: Have you set your crop tool to delete the cropped pixels?
(There is anew feature since ? to delete /just not show those pixels)

Well now!  That does appear to explain it.  Looks like that means the way it has always worked in the past became a new option. What might be the rationale for doing that?

Anyway, glad to now know how to do what I've always done in the past.  Many thanks for cluing me in.

(10-07-2021, 05:26 PM)rich2005 Wrote: I must admit I got lost off with the GOOD and the BAD, however

When posting screenshots of issues include the tool options and layers in the images. So many things in your work flow affect the result. Crop with allow growing on or off. Crop with delete cropped pixels  on or off.  Canvas size with width / height linked not linked.  Size of the layers (obviously different as shot 1 & 2 are single layer 3 & 4 are two layers)

I can get #4 easily with the Image -> Canvas size by adding to the initial values or multiplying factor to the initial values depending on what I want. Uniform size border or retain aspect ratio.
My apologies.  I did find it difficult to explain.  Especially when I didn't know how to (properly) describe what seemed to be happening.  I was trying to limit the amount of information in the screen shots, thinking that might make it less confusing.  Sounds like that simply didn't work.
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#5
Quote:What might be the rationale for doing that?

It is to be able to work with a photo and not destroying it.
You should be able to do what you want, but your photo should in the end still be intact.
Some people find that important.
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#6
(10-08-2021, 08:57 AM)nelo Wrote:
Quote:What might be the rationale for doing that?

It is to be able to work with a photo and not destroying it.
You should be able to do what you want, but your photo should in the end still be intact.
Some people find that important.
That does make sense to me.  It sounds like my question wasn't expressed very well.  New features are very common especially with a project under active development.  However, it would seem to me that when migrating to a new release having that default values for such options preserve the prior method of operation makes sense.  In that, have someone who wants to use the new capability consciously change the setting rather than force a dummy like me to have to do that in order to make it work the way it always has.

Thanks again for spotting my mistake.
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#7
(10-08-2021, 07:21 PM)ajax Wrote:
(10-08-2021, 08:57 AM)nelo Wrote:
Quote:What might be the rationale for doing that?

It is to be able to work with a photo and not destroying it.
You should be able to do what you want, but your photo should in the end still be intact.
Some people find that important.
That does make sense to me.  It sounds like my question wasn't expressed very well.  New features are very common especially with a project under active development.  However, it would seem to me that when migrating to a new release having that default values for such options preserve the prior method of operation makes sense.  In that, have someone who wants to use the new capability consciously change the setting rather than force a dummy like me to have to do that in order to make it work the way it always has.

I sort of agreee ith you, especially for this feature that seems to break a lot of things (including a few tutorials out there).
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