SUMMARY On high-DPI monitors where scaling factor is set to more than one, gwenview seems to upscale the image by scaling factor. Image appears pixelizated. Issue is demonstrated in the screenshot. STEPS TO REPRODUCE 1. Set scaling factor in settings > display settings to more than one (I use 1.3) 2. Open any image in gwenview OBSERVED RESULT Image is pixelizated, with jagged edges everywhere and generally looks pretty atrocious. (Right side of the screenshot/Gwenview window) EXPECTED RESULT Image is displayed normally, with no scaling applied (Left side of the screenshot/GIMP) SOFTWARE/OS VERSIONS Linux/KDE Plasma: 4.19.8-2-MANJARO KDE Plasma Version: 5.14.4 KDE Frameworks Version: 5.52.0 Qt Version: 5.11.2 ADDITIONAL INFORMATION Judging by the image quality, it appears that gwenview rescales image twice. It seems the following happens: 1. Gwenview calculates how big the window would be if the scaling factor was set to 1 2. Gwenview rescales the image to fit inside a window of dimensions calculated in step 1 3. Gwenview then upscales the image to fit inside the actual window, using nearest neighbour (upscaling the image from step 2)
Created attachment 117099 [details] Screenshot demo of the issue. Same image opened in GIMP (left) and Gwenview (right), both at 100%. GIMP displays image correctly, Gwenview upscales and completely ruins it.
*** This bug has been marked as a duplicate of bug 373178 ***