Created attachment 161809 [details] On the left you can see how the icon should be Most icon themes use icon sizes 16x16, 22x22, 24x24, 32x32... But with breeze they are 15x15, 20x20, 25x25... This is especially noticeable when using pixel perfect icons.
Cannot reproduce with my system running Plasma 6 Wayland at 200% scale. What Icon theme are you using? Does the issuereproduce when using the Breeze Icons theme? How did you make that screenshot? In an image editor, or is the icon on the left on the desktop or something? What version of Plasma are you running? Is this in the X11 or Wayland session? What screen scaling value are you using, if it's something other than 100%? Have you manually changed the "Force Fonts DPI" value to something other then its default value>
Created attachment 161894 [details] se98 icons In the first screenshot I'm using Papirus icon theme, I just pasted the original the left with gimp and upscaled it x2 so you don't have to zoom in. I used 100% scale. I left everything as set by default. The issue is just the icon size, so with scalable icon themes like breeze it isn't that noticeable. Text size also affects the icon size, as someone mentioned here https://github.com/paulmcauley/klassy/issues/62. Here's another screenshot with se98 icon theme, button size set to small, neon unstable plasma 5.27.80, x11.
So the blurry icons are raster icons, and not vector icons?
Created attachment 162056 [details] 16x16 scaled to 15x15 Oh sorry, perhaps I should rephrase. There is no blur issue, it's the icon size issue. If the icon size matches the icon theme size, then it doesn't get scaled and looks as intended (16x16, 22x22, 24x24...). But if that is not the case, then it gets scaled (resized) (the case with Breeze kdecoration), and with scaling the icon can get blurry. Raster icons are more noticeable, but it also affects vector icons (1px black line becomes 2px grey line, see attachment), that's just how it is. So I'm saying it would look better if the program icon size matched the icon theme size (16x16 for small and so on...). I've also seen that icon size settings are being removed all together for Plasma 6, so it would be nice if the icons looked as crisp as possible.
Thanks. I can't reproduce it with current git master, but I also have a 4K screen at 200% scale, so blurry icons look less prominent for me. Still they don't look blurry at all. Are you by any chance using a non-default window decoration icon size?
No, I didn't change anything.