https://bugs.kde.org/show_bug.cgi?id=408225
Bug ID: 408225 Summary: Canvas itself becomes transparent with transparent pixels, showing what is behind the Krita window Product: krita Version: 4.2.0 Platform: Kubuntu Packages OS: Linux Status: REPORTED Severity: normal Priority: NOR Component: OpenGL Canvas Assignee: krita-bugs-n...@kde.org Reporter: captains...@gmail.com Target Milestone: --- Created attachment 120509 --> https://bugs.kde.org/attachment.cgi?id=120509&action=edit Screenshot showing issue; note the desktop visible through the transparent orange areas Any pixels that are transparent and show the canvas (that is, show the checkerboard "transparent" pattern and would have an alpha of less than 1.0 if ultimately exported) seem to be showing what's behind the Krita window itself. That is, the desktop (or whatever else is there) becomes visible through the transparent areas. I stumbled across this when I noticed the antialiased edges of black Bezier curve vectors didn't look black on-screen. When I zoomed in, I saw the default Kubuntu wallpaper peeking out through the enlarged, transparent pixels. I tried it with other transparencies, and sure enough, they all showed my desktop behind the transparent areas. Curiously, if there's no pixel data at all in a given region (or the pixels are completely transparent), that area is NOT transparent to the desktop, and just the plain checkerboard is visible. If I turn off Canvas Graphics Acceleration in the settings, the problem goes away, leading me to believe this is something to do with OpenGL. STEPS TO REPRODUCE 1. Create a new image. 2. Draw a filled, opaque square by whatever means you wish. 3. Set the layer on which the square is to anything less than 100% Opacity. OBSERVED RESULT The desktop is visible through the transparent square and the transparency checkerboard. EXPECTED RESULT Only the checkerboard should be visible through the transparent square; the Krita canvas itself should not be transparent. SOFTWARE/OS VERSIONS Linux/KDE Plasma: Kubuntu 18.04, running Linux 4.15.0-50-generic from Ubuntu packages (available in About System) KDE Plasma Version: 5.12.7 KDE Frameworks Version: 5.47.0 Qt Version: 5.9.5 ADDITIONAL INFORMATION This problem shows up on both my desktop and my laptop. The desktop has a GeForce GTX 970, and the laptop has the mobile version of same. Both are running the same version of Kubuntu with the same KDE Plasma, Frameworks, Krita, and Qt versions. In the attached screenshot, you can see a diagonal yellow line from the default Kubuntu 18.04 wallpaper behind the transparent orange area ("Curtains Fore" in the layer list, currently set to 34% opacity for demonstration), as well as the icons for Inkscape and GKrellM in a folder widget on the desktop. Areas with no pixel data just show the checkerboard. -- You are receiving this mail because: You are watching all bug changes.