ttfsubset causes sileftml error "Invalid glyph index"

[bobh0303]

Summary:

• wscript includes call to ttfsubset ==> smith sileftml fails with Invalid glyph index message
• wscript excludes call to ttfsubset ==> smith sileftml passes

To reproduce:

Using the ScheherazadeNew branch ttfsubset_bug#1, build font (i.e.: smith distclean; smith configure; smith build) with default settings, then execute smith sileftml. Result will include an error:

libtexpdf:fatal: Invalid glyph index (gid 1686)

However, if font is built with -d option, i.e., smith distclean; smith configure; smith build -d, then smith sileftml completes without error.

NB: In wscript, -d suppresses the call to ttfsubset (which tries to make the fonts smaller).

[bobh0303]

Hm, I'm not seeing arab script (or its languages) retained in the subsetted font, in spite of what the wscript says:

ttfsubset -s latn,arab -l KIR,JUR,RHG,SND,URD,WLF ${DEP} ${TGT}

[mhosken]

To help debug this, it would be good to know what the missing glyphs are. Is it that the subset is missing cmap entries? or is an OT rule calling for a glyph id that has been removed?