wlr-screencopy protocol selecting incorrect regions with capture_output_region.

[ZnxTech]

Hyprland version

0.49.0

Regression

I am not sure since I haven't used it before discovering this bug.

Bug description

Hi, I have been working on a Wayland based screenshoting and sharing tool and noticed
that the wlr-screencopy protocol is selecting incorrect regions when using the capture_output_region request to create frames of monitors with a transform.
This bug appears to happen only when a part of the monitor is captured and not when the whole is captured using capture_output_region or capture_output requests.
I am using SHM buffers to store the screenshot data and I do not know if this bug happens with Linux DMA-BUF buffers as well.

Examples:
My second monitor which has this config: monitor=HDMI-A-2, 1920x1080@60, 2560x0, 1, transform, 3
and will be used for these examples.

zwlr_screencopy_ ... _region(state->wayland->wlr_screencopy_manager, 0, output_data->output, 0, 0, 720, 1280);
Resulting image: https://znx.s-ul.eu/WbfoV34r

zwlr_screencopy_ ... _region(state->wayland->wlr_screencopy_manager, 0, output_data->output, 320, 0, 720, 1280);
Resulting image: https://znx.s-ul.eu/yJkLo7UI

zwlr_screencopy_ ... _region(state->wayland->wlr_screencopy_manager, 0, output_data->output, 320, 640, 720, 1280);
Resulting image: https://znx.s-ul.eu/BtO8mY2d

zwlr_screencopy_ ... _region(state->wayland->wlr_screencopy_manager, 0, output_data->output, 0, 640, 720, 1280);
Resulting image: https://znx.s-ul.eu/v4ghcoxz

The whole screen: (and the only correct capture)
zwlr_screencopy_ ... _region(state->wayland->wlr_screencopy_manager, 0, output_data->output, 0, 0, 1080, 1920);
Resulting image: https://znx.s-ul.eu/QyyPge8P

note: this bug is not reproducible with Emersion's grim since it doesn't use the capture_output_region request but rather "crops" from capture_output.

System info and config

hyprctl_systeminfo.txt

[ZnxTech]

I made a patched version of Emersion's grim that uses the capture_output_region request instead which has the same buggy behavior.

https://github.com/ZnxTech/grim

Edit/Update:
Tested using this patched version of grim under sway and got perfectly fine and correct captures/images from it.

[vaxerski]

cheers, thank you.

[vaxerski]

#10470