Public bug reported:
Spectacle aborts with an OpenCV assertion when taking a screenshot on a
mirrored multi-monitor setup with different resolutions and fractional scales.
This looks similar to Bug https://bugs.kde.org/show_bug.cgi?id=503682, but
still reproducible on Spectacle 6.4.5.
Steps to Reproduce:
System Settings → Display & Monitor: set two displays (2560×1440 and 1920×1080)
to Mirror (Clone).
Set scales to 116% on the 2K display and 86.6667% on the 1080p display
(fractional scaling).
Start Spectacle 6.4.5.
Output:
```
terminate called after throwing an instance of 'cv::Exception'
what(): OpenCV(4.10.0) ./modules/core/src/matrix.cpp:808: error:
(-215:Assertion failed) 0 <= roi.x && 0 <= roi.width && roi.x + roi.width <=
m.cols && 0 <= roi.y && 0 <= roi.height && roi.y + roi.height <= m.rows in
function 'Mat'
Aborted (core dumped)
```
ProblemType: Bug
DistroRelease: Ubuntu 25.10
Package: kde-spectacle 4:6.4.5-0ubuntu2
ProcVersionSignature: Ubuntu 6.17.0-5.5-generic 6.17.0-rc7
Uname: Linux 6.17.0-5-generic x86_64
NonfreeKernelModules: zfs
ApportVersion: 2.33.1-0ubuntu3
Architecture: amd64
CasperMD5CheckResult: unknown
CurrentDesktop: KDE
Date: Mon Oct 13 19:12:26 2025
InstallationDate: Installed on 2023-04-13 (914 days ago)
InstallationMedia: Kubuntu 22.04.2 LTS "Jammy Jellyfish" - Release amd64
(20230223)
SourcePackage: kde-spectacle
UpgradeStatus: Upgraded to questing on 2025-10-09 (4 days ago)
** Affects: kde-spectacle (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug questing third-party-packages wayland-session
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https://bugs.launchpad.net/bugs/2127801
Title:
Spectacle 6.4.5 crashes with OpenCV ROI assert on Wayland with multi-
monitor (mirrored/different scale)
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