Bug 217819

Summary:

Update to cairo-1.3.4 worsen font rendering

Product:

[Fedora] Fedora

Reporter:

Deji Akingunola <dakingun>

Component:

cairo

Assignee:

Behdad Esfahbod <behdad>

Status:

CLOSED RAWHIDE

QA Contact:

Severity:

medium

Docs Contact:

Priority:

medium

Version:

rawhide

Target Milestone:

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Target Release:

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Hardware:

All

OS:

Linux

Whiteboard:

Fixed In Version:

Doc Type:

Bug Fix

Doc Text:

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Clone Of:

Environment:

Last Closed:

2006-12-20 20:23:15 UTC

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oVirt Team:

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RHEL 7.3 requirements from Atomic Host:

Cloudforms Team:

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Target Upstream Version:

Embargoed:

Attachments:

Description	Flags
Screenshot showing garbled text	none
font config	none
Implement _cairo_lround with floor(d+0.5)	none

Description Deji Akingunola 2006-11-30 03:58:20 UTC

Description of problem: Since updating to cairo-1.3.4 rawhide, font rendering
has somehow worsened on my computer. Some texts become garbled (as seen in the
attached screenshot), and short spaces are put between words (strings), e.g.
'mass.streamfunction' been rendered as 'm ass s.str eamfunction'. Moving the
cursor over the texts tends to smoothing it up, in case its garbled, and/or
're-group' the letters in situations where spaces show up in between words.
This rendering issue doesn't seem to be present in the default font setup (i.e.
/etc/fonts/fonts.conf), I have a local.conf (attached) in /etc/fonts (copied
from FC5 fonts.conf) that seems to be causing the issue.
It is perfectly reproducable, downgrading to cairo-1.3.2 does fix it for me.


Version-Release number of selected component (if applicable): cairo-1.3.4


How reproducible: Always


Steps to Reproduce:
1.
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3.
  
Actual results:


Expected results:


Additional info:

Comment 1 Deji Akingunola 2006-11-30 03:58:21 UTC

Created attachment 142462 [details]
Screenshot showing garbled text

Comment 2 Deji Akingunola 2006-11-30 04:00:51 UTC

Created attachment 142463 [details]
font config

Comment 3 Carl Worth (Ampere) 2006-12-02 01:02:07 UTC

Thanks for the report.

I've sucessfully reproduced this issue on my own system.

We're quite confident that this is due to a slightly modified rounding mode
which was implemented in cairo 1.3.4. The problem could be worked around in
nautilus, but we'll really need to fix this in cairo itself.

We're now talking on the cairo list about which approach to use to solve it.

I'll try to remember to post some patches here as well.

-Carl

Comment 4 Carl Worth (Ampere) 2006-12-02 01:40:29 UTC

Created attachment 142645 [details]
Implement _cairo_lround with floor(d+0.5)

This patch should fix the bug. It's a performance regression, but likely only
one that will be very noticeable on an embedded system without a hardware
floating-point unit.

We'll have this, (or another faster fix), in the 1.3.6 snapshot which is
planned for next week.

-Carl

Comment 5 Deji Akingunola 2006-12-02 02:09:40 UTC

Thanks, I can confirm the patch does indeed fix the bug. And BTW, the whole DE
on my system (a PIII) feels snappier with this new version (1.3.4, even with
this fix).

Comment 6 Behdad Esfahbod 2006-12-03 07:04:38 UTC

Deji, can you confirm that you have font hinting turned off?

Comment 7 Deji Akingunola 2006-12-03 13:39:00 UTC

(In reply to comment #6)
> Deji, can you confirm that you have font hinting turned off?
On the system where I took the screenshot, yes. But I see the same effect (of
spaces inserted between words) on another computer with hinting turned on (i.e,
slight hinting in the gnome font-preference).

Comment 8 Behdad Esfahbod 2006-12-04 17:37:45 UTC

Yeah, I seem to reproduce it for None and Slight hinting settings.

Comment 9 Behdad Esfahbod 2006-12-20 20:23:15 UTC

Fixed in cairo-1.3.6