Incorrect USE_MY_METRICS for some composite glyphs in 2.040

[sevmeyer]

I noticed a possible regression in release 2.040 (TrueType flavor). In all composite glyphs, the first reference is marked with USE_MY_METRICS (bit 0x0200). For some glyphs this seems incorrect and causes overlaps, at least on Linux:

(OpenSuse Leap 15, Firefox)

(FontForge)

Affected glyphs up to U+00FF:
U+0022 quotedbl
U+0025 percent
U+0060 grave
U+00A8 dieresis
U+00AB guillemotleft
U+00AF macron
U+00B4 acute
U+00B8 cedilla
U+00BB guillemotright
U+00BC onequarter
U+00BD onehalf
U+00BE threequarters
...

Release 2.020 does not have this issue.

[frankrolf]

Thank you for the detailed report. This seems to be the same as #161.
Unfortunately, I can reproduce some of what you’re seeing when saving a PDF with MS Word 2016 (16.0.9126.2336) using built-in “save” method.
Using Microsoft’s “print to PDF” creates a better document, but with some character substitutions.
However, I don’t see any issues at all when using “save as Adobe PDF”, which is a part of (paid) Acrobat DC.

Still investigating – originally this investigation was started to get to the bottom of #154 .

[miguelsousa]

@sevmeyer thanks for bringing this issue to our attention. I did a ttx dump of the percent glyph and it confirmed your findings. The incorrect flag was set by the ttfcomponentizer tool. See adobe-type-tools/afdko#709

v2.020

    <TTGlyph name="percent" xMin="35" yMin="-12" xMax="790" yMax="668">
      <component glyphName="zero.dnom" x="0" y="266" flags="0x4"/>
      <component glyphName="fraction" x="369" y="0" flags="0x4"/>
      <component glyphName="zero.dnom" x="457" y="0" flags="0x4"/>
    </TTGlyph>

v2.040

    <TTGlyph name="percent" xMin="35" yMin="-12" xMax="790" yMax="668">
      <component glyphName="zero.dnom" x="0" y="266" flags="0x204"/>
      <component glyphName="fraction" x="370" y="0" flags="0x4"/>
      <component glyphName="zero.dnom" x="457" y="0" flags="0x4"/>
    </TTGlyph>

[miguelsousa]

The fix to the ttfcomponentizer is done. Need to fix a second issue before new TTF files can be made.

[miguelsousa]

Fixed in this release https://github.com/adobe-fonts/source-sans-pro/releases/tag/2.045R-ro%2F1.095R-it