[maverick] libcairo2 fails to render color blends correctly with certain themes

[Harry]

I have a fully updated Maverick-AMD-64 alfa-2 installation with gnome-shell (gnome3-session).
So I use clutter and mutter too.
Motherboard: Gigabyte GA-MA790XT-UP4
Graphics card: NVidia GTX285

After upgrading libcairo2 (1.9.10-1ubuntu1) I noticed some serious rendering issues.
This seems to affect more certain themes, like human-theme.
Certain color blends render incorrectly, for example:
- scroll bars in application windows become fully white, with no color blends,
- same happens to text buttons (in Synaptic for example).

This is reproducible by customizing a theme and choosing "human" or "human-clearlooks" controls.

I also noticed, using synaptic for instance, pressing the reload button, the loading bar fails to show blending colors.
The upper area of the bar is completely white.

I used to have a lucid-AMD-64 installation with xorg-edgers PPA.
There too I had these issues with libcairo2-1.9.10 package.
See the bug #596192.

The package libcairo2_1.9.10-1ubuntu1 seems to have fixed the thumbnail issue.
The color blend issue still remains.
This also applies to the new libcairo2 package (1.9.12-1)

It may, however, very well be, that many of the rendering issues with the new libcairo2 are in fact issues in several other "stable" applications, like GTK-themes, using cairo application programming interface (API).
This being the case, we are in fact seeing these issues only now because of the new libcairo2 package.

[Sebastien Bacher (seb128)]

is that a duplicate of bug #596192?

[Harry (harry33)]

Hi Sebastian,

I would like to keep these bug reports separate because of the following reasons.

1) The bug report #596192 was originally made for xorg-edgers PPA and for lucid and for the reason that newer libcairo2 brought about issues with emerald.
2) The bug report #601220 (this one) was originally made for maverick development release, where new libcairo2 was pulled in.
The issues concerning color blends seems to have quite much to do with gtk-themes (like human-theme_0.39).

Now, as it is not even clear if there is anything wrong in the package libcairo2 concerning the color blend issue, please keep these bug reports separate.

My workaround for the time being is to use a gtk-theme not using color blends.
I personally chose the theme "human-clearlooks" with controls "mist". At least with gnome-shell it works swiftly, whereas themes with color blends work much more slowly.

[Sebastien Bacher (seb128)]

> 1) The bug report #596192 was originally made for xorg-edgers PPA and for lucid and for the reason that newer libcairo2 brought about issues with emerald.
> 2) The bug report #601220 (this one) was originally made for maverick development release, where new libcairo2 was pulled in.

Is the only reason then the difference of versions? You opened a bug against the ubuntu cairo component, issues about ppa should not be opened in launchpad so we should keep only one bug there

[Harry (harry33)]

Sebastian,

This is the reason for making a bug report ("596192) agains PPA version of libcairo2.
This is the a piece of advice taken from the xorg-edgers PPA:

"If you are not sure or you think it is a packaging issue, file a bug as normal in launchpad (using "ubuntu-bug xorg" or the name of the package) but mark the bug with "[xorg-edgers]" in the title and subscribe the last uploader."

However, I have contacted the PPA owner via e-mail too and he is well aware of this issue.

The package of libcairo2 in xorg-edgers PPA is now exactly the same as in maverick repo.
This being the case, we may not need the bug report "596192" any more.
It is important to concentrate on gtk-theme issue a bit more.

However, I do not use emerald any more, the package was out dated anyway.

[Harry (harry33)]

A few clarifications here.
First I must express my astonishment to the fact that so few people seem to have noticed the sluggish behaviour of desktops with new libcairo2 installed. The last version to work was the version 1.8.10 (in lucid), since then not any version has worked well.
One can easily see the sluggishness of the whole desktop (like in nautilus and synaptic) by changing gnome desktop themes (System-Preferences-Appearance).
For example, choose the theme Ambience or Dust Sand and in nautilus go quickly through menus or try to open a folder containing a lot of files (like .thumbnails/normal).
Then choose the theme Clearlooks and customize controls to Mist.
You will see a clear improvement in speed. But a lot simplier theme with no color blends.

[Sebastien Bacher (seb128)]

those issue might be driver specific, some nvidia users are getting corruption issues it seems when using the nvidia binary drivers

[Harry (harry33)]

Hi Sebastian,

Now that was an interesting observation.
I did some test to find out more about the issue.

I used another installation here for comparison:
lucid-64 bit fully updated with an ATI graphics card, HD2600 Pro and lucid's own xserver-xorg-video-ati_1.6.13.0-1ubuntu5 driver.
I compared libcairo2_1.8.10-2ubuntu1 (and libpixman-1-0_0.16.4-1ubuntu2)
to the maverics libcairo2_1.9.12-1 (and libpixman-1-0_0.18.2.1).

It was indeed interesting to note that with ATI graphics card there was no color blend issues with maverics libcairo2 and libpixman-1-0, but the sluggishness of the desktop was clear and easy to observ. So at least new libcairo2 still makes system slower to respond.

On the other hand, I also tested my maverick installation with NVidia graphics card, GTX285 + nvidia-current_256.35-0ububtu2 driver.
When I downgraded the libcairo2 to the version 1.8.10 (lucid), the colors blend issues and sluggishness both were gone.

[Harry (harry33)]

So after all, developers believe that cairo has evolved into a right direction and leaving certain software incompatible with it.
This being said, if it is accepted that software left incompatible (like NVidia proprietary drivers) there is no need anymore to regard this as a bug in gtk-themes nor libcairo2 itself.
Marking this bug report now invalid.

[Stephan Muhs (stephan-dinoco)]

If this is the direction of Ubuntu development, then bug reports seem indeed to become pointless. Unless it is broken for the systems the developers are using, it is not considered a bug. A very sorry state of affairs and a good way to make sure that bug #1 will never be resolved.

[Harry (harry33)]

Stephen,
I see your point.
Though I am not criticizing Canonical nor Ubuntu-developers, I can see there is a bad tendency nowadays to blaim NVidia quite easily.
I certainly do not hope Ubuntu developes into a direction where proprietary drivers do not work.
After all, quite a lot of hours has been spent to develope and to improve open source drivers (like nouveau).
Still we all must admit that NVidia proprietary drivers are far better, if not unreachable.
I do not know how this particular libcairo2 package developed into the current state, but there are several issues it brought about.

[Doug McMahon (mc3man)]

Due to (from my perspective), the unsuitability of the current 256 maverick drivers for agp cards, had previously reverted back to the 195 nividia-current (xserver-1.8

See absolutely none of the issues as described here and in https://bugs.launchpad.net/ubuntu/+source/nvidia-graphics-drivers/+bug/605979

Nor any slowdowns, ect. - using the default ambiance theme

[Yotam Benshalom (benshalom)]

This bug may be related or even a duplicate:
https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/612614

[Harry (harry33)]

The libcairo2_1.9.14-1ubuntu1 update fixed this bug in cairo.
Now all the themes render correctly and the desktop sluggishness is gone.

Also these are fixed as well
bug #595845
bug #612614