Hi, Recently, Alex gave me an idea to improve FT_Get_CID_From_Glyph_Index() API for CID-keyed font Type 0 (FontType 9, the most traditional CID-keyed font using PostScript Type1 CharStrings) by adding a fallback to CID=0 for the cases that the requested GID points to a broken entry providing no glyph data. cid_load_glyph() can catch such an error but cannot stop the Type1 CharString rendering after successful loading. Therefore, using cid_load_glyph() for validating CID is too expensive; FT_Get_CID_From_Glyph_Index() is interested in the presence of the glyph data but has little interest in its rasterization result. For simple checking of the presence of the glyph data, I propose to separate the glyph data loading part of cid_load_glyph() as 2 helper functions; one is for incremental loading, another is a traditional disk-resident font file. I drafted a few patches:
https://gitlab.freedesktop.org/mpsuzuki/freetype-mps-wip/-/compare/master...wip-t1cid-separate-loaders-of-fd-offsets?from_project_id=11053&straight=false But I need a good testing tool to check the possible regression for the incremental loading. One of the most straightforward ideas would be using GhostScript and some PostScript data generated by legacy printer drivers (which can emit the per-glyph Type1 CharString and embed it to the output but cannot make a self-standing CID-keyed font like that in PDF). But it is too big software. I wish there were smaller - no need to render seriously - testing tools. I tried to find something in the mailing list archive around 2002 Jun-Jul (when the main trunk merged the incremental loading feature, 22 years ago!), but I could not find anything. Please let me know if anybody can remember how the developers tested in those days. Nothing to say; I've already tried GhostScript. But GhostScript uses t1_load_glyph instead of cid_load_glyph. The client of FreeType's incremental loading feature. https://git.ghostscript.com/?p=ghostpdl.git;a=blob;f=base/fapi_ft.c;hb=HEAD The emitter of the font stream for the FreeType. https://git.ghostscript.com/?p=ghostpdl.git;a=blob;f=base/write_t1.c;hb=HEAD There is an emitter of the incremental downloading font dictionary for PostScript Type1 font, write_t1.c written by Graham Asher himself), but there is no emitter for Type9 font (CIDFontType0 font). Regards, mpsuzuki
