OS Archlinux DE xfce WM compiz Driver intel 2.99.917.639.gcac8e1e Accel method sna Shadow in Compiz are pixelated especially on the left and righ sides. If I use uxa the problem goes away, but using uxa slows down significantly the system Looking at internet it seems related to cairo library. Please could you help? Thanks Gianluca
Created attachment 123189 [details] Screenshots of the pixelated shadow
Limited precision bug. What hardware? Please attach your Xorg.0.log.
Hmm. Actually it may be that the second pass is being clipped unexpectedly so the horizontal outside areas are not being smoothed.
A little bit of investigation, and the issue is the quantization artefacts.
I put a cap in so that the shadow doesn't become too pixellated: commit bca4e0e35e4ac27f2dcd1a8e5fcbf7ce69cec358 Author: Chris Wilson <chris@chris-wilson.co.uk> Date: Sat Apr 23 21:42:12 2016 +0100 sna: Limit generic convolution to smallish kernels Since the naive implementation uses an 8bit temporary, we can only support so many passes before the quantization artefacts become apparent. We have to be extra conservation in order to support multi-pass convolution algorithms (notable 2-pass separable Gaussian kernels). References: https://bugs.freedesktop.org/show_bug.cgi?id=95091 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> It's a tradeoff that hopefully should allow small drop shadows (~15 pixels) to be naively acceleration without looking atrocious. It would be possible to fully support convolution kernels on recent hardware, might be an interesting challenge.
Hi Chris, I recompiled and tested: works like a charm! You are really a master. It is a teaching lesson for me of how nice is the concept of free open source community: there is always somebody there to help you and you on your turn can help somebody. I will cascade to compiz community Thanks again Gianluca
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