Chart test failures on mac: text size differences

[Khaled Hosny]

On Mon, Mar 06, 2017 at 11:21:25AM +0000, Tamas Zolnai wrote:
> On Tuesday, February 28, 2017 23:42 GMT, Khaled Hosny <khaledhosny at eglug.org> wrote:
> 
> > On Tue, Feb 28, 2017 at 11:02:30PM +0000, Tamas Zolnai wrote:
> > > Hi Khaled,
> > >
> > > > I don’t think text width or height are that interesting, but they are
> > > > probably a good approximation, so I repurposed one of the existing VCL
> > > > tests to test this[1]. I tried testing also the text bounding rectangle
> > > > but it showed a 1 pixel difference on Mac, this should be fixed in [2].
> > > >
> > > > Feel free to add more test cases that you think are worth having.
> > >
> > > I noticed today that some of the Windows tinderboxes fails on the new
> > > vcl test randomly. They fail on the text width check.  This can
> > > explain why chart test were failing on the same Windows tinderboxes.
> > >
> > > http://tinderbox.libreoffice.org/cgi-bin/gunzip.cgi?tree=MASTER&brief-log=1488318182.31559
> > > http://tinderbox.libreoffice.org/cgi-bin/gunzip.cgi?tree=MASTER&brief-log=1488315724.23850
> >
> > That is weird! Any chance that these machines has a copy of DejaVu Sans
> > installed system wide that we might be picking instead of the bundled
> > one?
> >
> > This change[1] might help showing the source of the difference that is
> > causing the failures.
> 
> Hi Khaled,
> 
> Did you see the current build failures?
> Here are two failures:
> http://tinderbox.libreoffice.org/cgi-bin/gunzip.cgi?tree=MASTER&brief-log=1488779385.27281
> http://tinderbox.libreoffice.org/cgi-bin/gunzip.cgi?tree=MASTER&brief-log=1488782916.5676
>
> Interestingly it's the same tinderbox which is sometimes happy with
> the test, sometimes fails with 75 and sometimes fails with 91 as text
> width.
> Clearly we have some wierd behavior here.


Unfortunately we still don’t get much information to debug this,
hopefully [1] will help a bit e.g. to see if there are accumulating
small differences in character widths which would suggest rounding
issues, or completely different ones which would suggest a different
font. Unfortunately OutputDevice has no public API to tell which font it
ended up using.

Regards,
Khaled

1. https://gerrit.libreoffice.org/gitweb?p=core.git;a=commitdiff;h=9af45ef67824f3ec6e95c16e7deb005a73532d65