Bug 346956

KWin takes the icon that is exported on the window (but may be available in multiple sizes)

-> Which decoration in particular? (what the deco does with the icon pixmaps is up to the deco, so this is relevant)
(in doubt attach the output "qdbus org.kde.KWin /KWin supportInformation")

Since this may be a HiRes issue, what's the output of "xdpyinfo | grep resolution"?

Created attachment 92341 [details]
qdbus org.kde.KWin /KWin supportInformation

The issue seems to be more visible with Oxygen than with Breeze, but it seems both need to resize the icons for at least small and normal button size.
As they don't have the same icon size, I understand there can't be an icon with the exact size for all configurations, but with Oxygen on KDE4 it was the case.
I don't know if Oxygen now uses a different size for the display, or if it selects the wrong icon size as source pixmap.

"xdpyinfo | grep resolution" gives "resolution:    96x96 dots per inch".

@Hugo, I didn't check the code, but resizing small images requires lanczos filtering or similar or indeed will inevitably end up being blurry (not to mention scaling up)

Since QImage doesn't provide such, you'll get "best" results scaling down the biggest image you can get (ie. 512 -> 18 >> 24 -> 18), but in doubt, just omit it (since loading/scaling bigger images oc. also has more overhead)

But small icons are sometimes different from bigger ones, with details removed to stay readable and sharp, so it's better if we can use exact sizes (16x16, 22x22, ...).
Oxygen seems to use an intermediate icon size for the small buttons (which roughly matches the KDE4 normal size). In KDE4 the icon size was fixed, now it changes with the button size.

Reassigning to breeze as KWin cannot do much more than passing the icons to the decoration. The actual rendering is done by the decoration plugin.

(In reply to Martin Gräßlin from comment #6)
> Reassigning to breeze as KWin cannot do much more than passing the icons to
> the decoration. The actual rendering is done by the decoration plugin.
The issue isn't specific to breeze, it also affects oxygen window decorations.

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This bug has been in NEEDSINFO status with no change for at least
30 days. The bug is now closed as RESOLVED > WORKSFORME
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