Created attachment 11327 [details] demonstration The attached document fails to render as expected because MuPDF doesn't provide metrics of embedded fonts to FreeType when they're missing in the font itself. Ghostscript seems to be able to handle this case as expected.
We've got another report of this at https://code.google.com/p/sumatrapdf/issues/detail?id=2790 .
In MS specification TTF in https://www.microsoft.com/typography/tt/ttf_spec/ttch02.doc clean write: table 'hmtx(horizontal metrics)' is required. And in https://www.microsoft.com/typography/tt/ttf_spec/ttch03.doc this required too. But font without hmtx exist (mostly as embedded font in pdf). Your example is indicative ( i have same pdf too) - on Windows they open without any problems but in linux - font is adsent. I create bug in "FreeType Project" https://savannah.nongnu.org/bugs/index.php?44169 , but after (if it will be fixed) pdf anyway not opening correct. With patch poppler from https://bugs.freedesktop.org/show_bug.cgi?id=88939 pdf be opening correctly and font visible and readable. (mostly clean - wrong codepage - view be in xpdf, another viewers sometime show blank gliph instead wrong)
In freetype bug reopened from https://savannah.nongnu.org/bugs/?44169 to whishlist https://savannah.nongnu.org/bugs/?44184
Freetype commit for fix font load is http://git.savannah.gnu.org/cgit/freetype/freetype2.git/commit/?id=92359bd8851448ba40167affdf5663659a7b28f0 That commit can bee included in freetype 2.6.0 version. With that commit all opened and showed OK in mupdf. (In poppler that problem remains https://bugs.freedesktop.org/show_bug.cgi?id=88939 ) That bug can bee closed.
We have adopted freetype 2.5.5, but this bugfix isn't in that release. We'll keep this bug around until the next release is available.
FWIW Freetype 2.6.0 is now available.
Fixed in commit 70ed309e1c69ab8cd7e107f27d101f9a13416333 Author: Tor Andersson <tor.andersson@artifex.com> Date: Tue Oct 6 13:55:14 2015 +0200 Update freetype submodule to version 2.6.1.