I think once we can figure out the transform issue, this PR will be ready to merge?

@Decodetalkers said, in #40 :

it seems something wrong with capture_region, I think it is the bug of sway, because rotate 90 degree, capture region from 0, 0, 100, 100, it captures from 2400, 1000, -100, -100, and grim does not use capture_region. it capture all the screens, and caculate where to cut, finally makes an image

This is definitely a bug in Sway. The documentation for zwlr_screencopy_manager_v1::capture_output_region states that "The region is given in output logical coordinates, see xdg_output.logical_size.". For a square (e.g. 1000x1000 pixel) output, changing the geometry transform will not affect the logical size of the output; in all cases, the compositor will render the same image, just transformed differently. As a result, capturing a specific output region should produce the same result/capture the same area, no matter which geometry transform was applied. Testing with wayshot and e.g. swaymsg output WL-1 transform 90 vs swaymsg output WL-1 transform 0 confirms that Sway does not always capture the same logical region, as it should.

A test script, in case it is useful:

#!/bin/sh
# requires square output for best results
swaymsg output '*' transform 0
wayshot -s '0,0 100x100' -f test-0.png
swaymsg output '*' transform 90
wayshot -s '0,0 100x100' -f test-90.png
swaymsg output '*' transform 180
wayshot -s '0,0 100x100' -f test-180.png
swaymsg output '*' transform 270
wayshot -s '0,0 100x100' -f test-270.png
swaymsg output '*' transform flipped
wayshot -s '0,0 100x100' -f test-0f.png
swaymsg output '*' transform flipped-90
wayshot -s '0,0 100x100' -f test-90f.png
swaymsg output '*' transform flipped-180
wayshot -s '0,0 100x100' -f test-180f.png
swaymsg output '*' transform flipped-270
wayshot -s '0,0 100x100' -f test-270f.png
swaymsg output '*' transform 0

I've filed an MR that fixes the issue at https://gitlab.freedesktop.org/wlroots/wlroots/-/merge_requests/4249 .

Edit: it has been merged; we should all test transform handling using wlroots built from git master, from now on.

I think once we can figure out the transform issue, this PR will be ready to merge?

At least part of the transform issue isn't something wayshot can fix.

Thank you for the comprehensive report. ❤️

I'm really sorry. I'm stupid. I forgot to change the branch.

Also would you guys mind if I add you both as repo collaborators, would be helpful to have the patch branches here itself. Let me know if you're interested.

It's not rotated at all. @Decodetalkers Are you testing this branch or your branch? I tested with your branch again and it seems to work. With this branch it doesn't.

I'll try to find the issue. Also would you guys mind if I add you both as repo collaborators, would be helpful to have the patch branches here itself. Let me know if you're interested.

I test mime, it works, so I don't have clue why this branch not work.. emm..

I will feel glad if I can help

Nope I'm just stupid. It works fine.

I have written a solution to multi-output transformed screenshots with reference to the commit that @Decodetalkers made: 0d9ed3f.

I need to find an ergonomic way to do the same for single output screenshots and I think this PR will be ready.

I have fixed single output transforms handling too. I will do some cleanup and commit it.

@mstoeckl @Decodetalkers Thank you so much for your help, it would be impossible to get this PR finished without you guys. I have completed transform handling and committed it.

If you guys can leave a review that would help a lot. I'll rebase and merge after the review.

Merged to main branch.