artifacts with --backgroundless or visible mouse click when uses opacity

[GoogleCodeExporter]

I have noticed there is a problem (artifacts) when setting opacity of shaped 
window (--backgroundless and visible mouse click). I thought it was my 
computer's problem at first, but it's not.

I found this post [1], a C program uses shape and cairo, it works perfectly. I 
am guessing it's about the alpha and colormap. I have tried to make some 
existing Python example to work, but I didn't have luck.

I will find some time to learn how that C program works, however if anyone has 
already had experience, you are welcome to give me hints, or just to fix the 
problem.

[1] http://macslow.net/?p=26

Original issue reported on code.google.com by [email protected] on 19 Aug 2011 at 5:55

[GoogleCodeExporter]

After digging around, I managed to port the C code to nearly equivalent Python 
code. Unfortunately, it doesn't work like the C code. It still has artifacts.

I then tried different WM, Fluxbox. Out of my expectation, they both didn't 
work well. I think they both couldn't have shape or something, I tried too many 
things and didn't take notes.

Then I booted up with Gentoo 2011 Live DVD, which uses KDE. After enabled 
Desktop Effects, they both work. But another surprise, the C code has slight 
dark background, though it remain translucent. But the Python code works 
perfectly.

I emerged compiz 0.8.6. Both work. And, key-mon works as well, setting opacity 
does not create artifacts. With --no-press-fadeout, that works like a charm. 
(though I found when window comes back for a keypress, it steals focus, a bug)


So far, I think compositing manager is really an issue here, but I am not so 
sure.

I will be waiting for more feedback on this, before then, I am putting this at 
the end of my ToDo list.

Original comment by [email protected] on 20 Aug 2011 at 11:59

• Changed title: artifacts with --backgroundless or visible mouse click when uses opacity
• Added labels: Priority-Medium
• Removed labels: Priority-High

Attachments:

• input_shape_test.py