[Okular-devel] [okular] [Bug 335058] New: PDF Text hinting does not work for embedded otf fonts (CID Type 0C), does work for truetype.

[Jerome]

https://bugs.kde.org/show_bug.cgi?id=335058

            Bug ID: 335058
           Summary: PDF Text hinting does not work for embedded otf fonts
                    (CID Type 0C), does work for truetype.
    Classification: Unclassified
           Product: okular
           Version: 0.18.5
          Platform: Fedora RPMs
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: NOR
         Component: PDF backend
          Assignee: okular-devel at kde.org
          Reporter: ce0c5679c447a438 at mailinator.com

I've created a pdf file with XeLatex that includes two versions of the libre
TeX Gyre Pagella font,
one version is taken from an original otf file and the other is a ttf file
generated from that otf file 
using fontforge, each version of the font is used to render one line of text. 
The line corresponding to the otf font is not hinted - easily seen visually
when zooming out. Toggling hinting in the preferences has no effect either. The
line rendered using the truetype version 
renders fine, and toggling the hinting in the preferences has a noticable
effect.

As I mention in additional info, this also happens with evince and other
viewers, but
not acrobat reader. If it's not an okular issue, please point out the right
project
to contact about this if possible.

If I can figure out how to attach files to this issue, I've got a screenshot
and a pdf for repro.


Reproducible: Always

Steps to Reproduce:
1. open the enclosed pdf in okular
2. zoom out sufficiently so the type is small (fit to page on a 20" monitor
works)

Actual Results:  
Notice the first line (otf) is quite dark while the lower line is crisp
toggle text hinting in the preferences and note how the upper row is unaffected
while the lower row goes back and forth between nice and not that nice.

Expected Results:  
I expected the two lines to exchibit marginal diffeence visually.

I've looked at the following:
- It's not an issue with TeX Gyre Pagella, I originally saw this with another
unrelated font.
- I don't think the fontforge conversion process plays a part, since the output
renders *better*
then the original and In any case i've also tried hinting the otf file directly
with Adobe's FDK,
with no changes. The fact that toggling hinting in the preferences has no
effect also suggests
the conversion didn't "fix" the font.
- I've looked through my fontconfig files (/etc/fonts,
~/.fonts.conf,~/.config/fontconfig/fonts.conf)
and while there's some hinting toggles there, there's nothing I've seen which
could account
for the difference specifically between otf and ttf files, and I'd expect
okular's preferences to
override these anyway if fontconfig plays a part at all.
- Adobe acrobat reader doesn't have this issue. *But* evince has the same issue
and so does an embedded viewer in another linux program.

Environment
===
This manifests on an updated fedora 20 x86-64 system, which contains the 0.18.5
version
of okular. I've also compiled and tested this on current git master (268aa60)
with the same
problem manifesting.

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