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The "TrueTypeInPostScript" page has been changed by cbowditch. http://wiki.apache.org/xmlgraphics-fop/TrueTypeInPostScript?action=diff&rev1=1&rev2=2 -------------------------------------------------- == Introduction == - I (JeremiasMaerki) was asked to compile some pointers and hints concerning the addition of TrueType/OpenType support for PostScript output. At the moment (Mai 2010), we only support Type 1 fonts in PostScript output. + I (JeremiasMaerki) was asked to compile some pointers and hints concerning the addition of TrueType/OpenType support for PostScript output. At the moment (May 2010), we only support Type 1 fonts in PostScript output. == Requirements == * The PostScript renderer/painter shall learn to support Asian fonts including Chinese, Japanese and Thai fonts. (This does not necessarily mean the inclusion of non-LR-TB writing modes!) + * All the CJK Fonts that we have found from open source and commercial providers have been either TTF CID-keyed or OTF with CFF glyphs. So FOP must support both CID-keyed and OTF with CFF glyphs. + * All the CJK Fonts that we have found appear to be very large, i.e. > 5 Mb, so the Postscript Renderer needs to be able to support sub-setting to keep the output size down to reasonable levels. == Gathered hints and thoughts == @@ -17, +19 @@ TrueType support was introduced during the transition from PS level 2 to 3. Some late level 2 interpreters (version >= 2010) have support for Type 42 (TrueType) - fonts. Of the level 3 interpreters, all do. We should probably limit support for TrueType to level 3 PostScript so we can reduce support issues. + fonts. Of the level 3 interpreters, all do. We should limit support for TrueType to level 3 PostScript so we can reduce support issues and the complexity of having to deal with Type 42 fonts. There are several approaches to handling TrueType fonts, like in PDF. One is to create multiple single-byte encodings like we do for Type 1 fonts (encoding-mode="single-byte" in FOP's configuration). The other is CID-keyed fonts which are a bit more complex (default mode with PDF - output when using TTF fonts). In both cases it should be possible to - work with TTF subsets. + output when using TTF fonts). All the CJK fonts that we've found appear + to be CID-keyed fonts, so we need to support the extra complexity of CID-keyed. It seems to be possible to incrementally define a TTF font in PS (keyword: GlyphDirectory). However, that could interfere with @@ -35, +37 @@ font embedding and then use the GID from the TTF file to access the glyphs. - Like we do with PDF output, we should only implement TTF subsetting if we - take the CID-keyed font route. Due to the learning curve, it is suggested to - implement full embedding and multiple single-byte encodings - (encoding-mode="single-byte") first and subsetting later (if necessary at all). Keep in mind that full font embedding may offer the possibility to pre-install a font on the printer and just reference it in PostScript. However, I've never worked with TrueType fonts on PostScript so I can't @@ -71, +69 @@ * PSPainter * PSTextPainter (for SVG text) - In case OpenType fonts with CFF glyphs shall be used, it may actually make sense to add CFF + For OpenType fonts with CFF glyphs, it may actually make sense to add CFF support to our TrueType/OpenType loading code and try to use the CFF glyphs in PostScript since PS supports CFF fonts (Type 2 fonts). However, I don't know if there are any insurmountable differences between PS CFF support --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
