Crash when "scale pixels" module is moved on top of pixelpipe and "rotate and perspective" is used about darktable HOT 5 OPEN

What were you trying to achieve by moving it up in the pixelpipe?

There's a reason behind the pixelpipe ordering and you just discovered it.

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What were you trying to achieve by moving it up in the pixelpipe?

There's a reason behind the pixelpipe ordering and you just discovered it.

See my post above:

Motivation for using and moving scalepixels module on top of the pixel pipeline is the following:
If the module is activated after finishing a picture with several masks and drawings in the retouch module, the image warping is not reflected in the masks if it stays above demosaicing. Hence I moved it on top of all modules, except the crop module.

More concretely: after finishing a picture, I might notice that the desired crop does not work out without cropping away important parts of the image. Using the scale pixels module I'm able to squeeze the picture to make it fit into the aspect ratio of my desired crop.

That being said: the only module which causes this crash is "rotate and perspective", all others which might be sensitive above image boundaries (e.g. retouch and lens correction) do not lead to a crash or other issues. That's why I think it's a bug and the pixel pipe should be able to handle this rearrangement, but I'm not an expert on the concepts and limitations of the pixel pipe, so I'm open to discuss my expectations ;)

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From the user manual....

Some cameras (such as the Nikon D1X) have rectangular instead of the usual square sensor cells. Without correction this would lead to distorted images.

So IIUC you're using the scale pixel module to correct a mask problem?

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Apologies for giving a more precise answer only after sending my original reply, I edited it.

So my motivation is to make the final edit fit into a certain aspect ratio and crop. Let's say, I'm editing a 3:2 image and apply some corrections which modify the image area and therefore also the aspect ratio, like horizontal and/or vertical lens shift in the "rotate and perspective" module, or the lens correction module. Afterwards I want to be able to apply a 3:2 crop again, without sacrificing image area for the crop. The "scale pixels" module can be use to either squeeze (>1) or stretch the image vertically to make everything fit into the crop I need. Did this explanation help?

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Now I understand.

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