Created attachment 139693 [details] Testprogram Max Staudt asked me to open a new report instead of https://bugs.freedesktop.org/show_bug.cgi?id=99705 While testing MSEide+MSEgui on OpenSUSE Leap 42.2 on a Acer Veriton M4640G I found that XDrawLine() has wrong line ends, see attached test-program and screenshot (wrong.png). 32 bit openSUSE 13.2 on the same machine shows the correct result (ok.png). Xorg log is attached. Please see also https://bugzilla.opensuse.org/show_bug.cgi?id=1021803 https://lists.x.org/archives/xorg-devel/2017-February/052624.html I hope that X11 again will provide fast and precise line drawing primitives. Lines where endpoints sometimes are drawn and sometimes not are useless IMHO.
Created attachment 139694 [details] wrong.png
Created attachment 139695 [details] ok.png
Created attachment 139696 [details] Xorg log
Created attachment 139697 [details] xephyr1.png
Created attachment 139698 [details] xephyr2.png
Created attachment 139699 [details] OpenGL implementation of upper part of the test program
Created attachment 139700 [details] XSetLineAttributes(disp,gc,1,LineSolid,CapButt,JoinMiter);
Created attachment 139701 [details] XSetLineAttributes(disp,gc,1,LineSolid,CapProjecting,JoinMiter);
Created attachment 139702 [details] Test program with line width 1
Created attachment 139703 [details] Line drawing program.
I've sent a patch upstream to try to fix accelerated rendering for 0-width lines, and the discussion that evolved was here: https://lists.x.org/archives/xorg-devel/2017-February/052624.html As far as I can see, upstream developers agree that a) this *is* a problem b1) either we turn off acceleration completely for 0-width lines, or b2) it has to be implemented as a shader that draws exactly how mi does. I'm happy to assist in refreshing memories here, as well as recount what I've seen during my downstream debugging, as far as I can remember. However, please don't be offended if I get off the CC list eventually, as I will no longer be maintaining the openSUSE graphics stack, and anything up until then will be in my private capacity. I'll mark the old bug (which I reported in Martin's place) as a DUPLICATE of this bug, so I am off the hook there. Thanks Martin for opening this new bug, and thanks to the upstream Xorg maintainers for looking into this :)
*** Bug 99705 has been marked as a duplicate of this bug. ***
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