Bug 851790 - Glyphs with multiple unicode encodings inhibit subsetting
Summary: Glyphs with multiple unicode encodings inhibit subsetting
Alias: None
Product: Fedora
Classification: Fedora
Component: liberation-fonts
Version: 17
Hardware: All
OS: All
Target Milestone: ---
Assignee: Pravin Satpute
QA Contact: Fedora Extras Quality Assurance
Depends On:
TreeView+ depends on / blocked
Reported: 2012-08-25 20:43 UTC by Deron Meranda
Modified: 2012-09-05 10:14 UTC (History)
4 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Last Closed: 2012-09-05 10:14:38 UTC

Attachments (Terms of Use)
Report on all the glyphs with multiple unicode encodings (8.93 KB, text/plain)
2012-08-25 20:43 UTC, Deron Meranda
no flags Details

Description Deron Meranda 2012-08-25 20:43:13 UTC
Created attachment 607011 [details]
Report on all the glyphs with multiple unicode encodings

Description of problem:
There are several glyphs which are mapped to more than one Unicode encoding at the same time. These glyphs inhibit automated subsetting because it is not easy to delete just one encoding slot without deleting both (as they share the same glyph object).  See the attachment for a listing of these glyphs.

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

Expected results:
Ideally these cases should use a glyph reference where stroke information must be shared.

Additional info:
These glyphs are identified by looking at the alternate unicode encodings property of the glyphs. If using the Python scripting to FontForge, look at the 'altuni' member of the glyph.  Also each glyph object for each encoding slot should be a separate object.  For example in the regular serif font:

>>> font = fontforge.open('LiberationSerif-Regular.sfd')
>>> font[0xfb01]
<fontforge.glyph object at 0x7fdf4387d688>
>>> font[0xf001]
<fontforge.glyph object at 0x7fdf4387d688>

Notice how the glyph object id is identical for both U+FB01 and U+F001.

Comment 1 Pravin Satpute 2012-08-27 12:12:24 UTC
Yes, even fontforge says "It is possible to have one glyph assigned to two unicode code points (This is not recommended, but it is possible)."  


Glyph reference looks better option to keep consistency in shape of the both characters.

Thanks for identifying characters affected by this, i will do these required changes.

Comment 2 Pravin Satpute 2012-09-05 10:14:38 UTC
i have committed changes in upstream. will be available with next release. 
please reopen if any problem.

Thanks !!

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