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Bug 477444

Summary: x11-libs/cairo[xlib-xcb] causes ugly font rendering in gtk (compared to cairo-1.12.14-r2)
Product: Gentoo Linux Reporter: Alexandre Rostovtsev (RETIRED) <tetromino>
Component: [OLD] LibraryAssignee: Ben de Groot (RETIRED) <yngwin>
Status: RESOLVED FIXED    
Severity: normal CC: brebs, robink, x11
Priority: Normal    
Version: unspecified   
Hardware: All   
OS: Linux   
Whiteboard:
Package list:
Runtime testing required: ---
Attachments: emerge --info output
screenshot with cairo-1.12.14-r2
screenshot with cairo-1.12.14-r3

Description Alexandre Rostovtsev (RETIRED) gentoo-dev 2013-07-20 03:44:16 UTC
Created attachment 353684 [details]
emerge --info output

Updating from cairo-1.12.14-r2 to cairo-1.12.14-r3 causes the fonts in all gtk2 and gtk3 applications to be rendered quite ugly (too much hinting, too thin, and looks like the wrong subpixel order for my screen).

Both revisions were emerged with the same USE flags: X glib opengl svg xcb (-aqua) -debug -directfb -doc (-drm) (-gallium) (-gles2) -legacy-drivers -openvg (-qt4) -static-libs -valgrind
Comment 1 Alexandre Rostovtsev (RETIRED) gentoo-dev 2013-07-20 03:45:45 UTC
Created attachment 353686 [details]
screenshot with cairo-1.12.14-r2
Comment 2 Alexandre Rostovtsev (RETIRED) gentoo-dev 2013-07-20 03:46:41 UTC
Comment on attachment 353686 [details]
screenshot with cairo-1.12.14-r2

gedit-3.6 screenshot with cairo-1.12.14-r2 - this looks good on my monitor
Comment 3 Alexandre Rostovtsev (RETIRED) gentoo-dev 2013-07-20 03:47:42 UTC
Created attachment 353688 [details]
screenshot with cairo-1.12.14-r3

gedit-3.6 screenshot with cairo-1.12.14-r3 - this looks terrible on my monitor
Comment 4 Matt Turner gentoo-dev 2013-07-20 04:39:45 UTC
cairo-1.12.14-r2 says:

> # --disable-xcb-lib:
> # do not override good xlib backed by hardforcing rendering over xcb

and cairo-1.12.14-r3 silently adds

> +		$(use_enable xcb xlib-xcb) \

Regardless if this is your issue, we should revert this.
Comment 5 Paul Bredbury 2013-07-20 13:17:44 UTC
That new use_enable is wrong, take a look at the cairo compilation output - choice tidbits:

The following surface backends:
  XCB:           yes

The following functions:
  X11-xcb functions: no (disabled, use --enable-xlib-xcb to enable)

So for Gentoo there should/would be 2 use flags: xcb and xlib-xcb.

However, who actually *benefits* from --enable-xlib-xcb? On Nvidia, for me it's always been noticeably slower in firefox, in the simple operation of opening a new tab and having 9 preview panes drawn in the empty tab.
Comment 6 Rafał Mużyło 2013-07-20 16:53:39 UTC
There's also that little catch, that xlib-xcb (at least last time I've checked - granted it was awhile here) causes artifacts in some of the corner cases in firefox.

Though even if that's still valid, you never know with firefox whose fault is it.
Comment 7 Alexandre Rostovtsev (RETIRED) gentoo-dev 2013-07-21 20:07:06 UTC
Emerging cairo-1.12.14-r3 with EXTRA_ECONF=--disable-xlib-xcb fixes the font rendering problem.
Comment 8 Chí-Thanh Christopher Nguyễn gentoo-dev 2013-07-21 23:21:35 UTC
The reason why I enabled it is bug 441878 comment 9. But it appears that not all users benefit from this so I will make it optional in the next revbump, and NX packages need put blockers or documentation in place.
Comment 9 Chí-Thanh Christopher Nguyễn gentoo-dev 2013-07-22 01:22:49 UTC
1.12.14-r4 now has xlib-xcb USE flag