Re: [ft-devel] ttfautohint 0.6 has been released
Werner LEMBERG w...@gnu.org writes: Today in the morning, while still dozing, I had a great idea how to largely simplify hinting of composite glyphs, and which solves the Roboto issue at the same time. Heh, you have your best coding ideas while half-asleep too eh...? :} -miles -- Monday, n. In Christian countries, the day after the baseball game. ___ Freetype-devel mailing list Freetype-devel@nongnu.org https://lists.nongnu.org/mailman/listinfo/freetype-devel
Re: [ft-devel] ttfautohint 0.6 has been released
Today in the morning, while still dozing, I had a great idea how to largely simplify hinting of composite glyphs, and which solves the Roboto issue at the same time. In particular, I believe that I've found a way to completely avoid fiddling with point indices. Following this route I shot myself in the foot :-( Some details: Let's assume that we have glyph `Agrave', a composite of `A' and `grave'. Before version 0.6, ttfautohint hinted `A' first, then `grave', and the hinted subglyphs got glued together afterwards. In 0.6, however, ttfautohint works differently: It now hints the whole glyph, this is, composites get recursively expanded so that they form simple glyphs, then hints are applied -- this is the normal working mode of FreeType's autohinter. Obviously, this gives better rendering results because the autohinter can consider the glyph's complete shape. The only drawback is an increased output font size since more glyphs are fully hinted. One problem, however, must be solved: We have to deactivate hinting for subglyphs (which usually are used as normal glyphs also) so that nothing but the final bytecode of the composite gets executed. The trick introduced in 0.6 is to prepend a composite called `.ttfautohint', a dummy glyph with a single point, and which has a single job: Its bytecode increases a CVT register (I call it `cvtl_is_subglyph'), indicating that we are within a composite glyph. Returning to our example, `Agrave' now consists of three subglyphs: `.ttfautohint', `A', and `grave' (in this order). The bytecode generated by ttfautohint has been slightly modified so that `cvtl_is_subglyph' is honoured, and the bytecode of the composite glyph decrements this counter accordingly: bytecode ofaction --- .ttfautohint cvtl_is_subglyph += 1 (now: 1) A do nothing because cvtl_is_subglyph 0 grave do nothing because cvtl_is_subglyph 0 Agrave cvtl_is_subglyph -= 1 (now: 0) apply hints because cvtl_is_subglyph == 0 The trickiest part was to adjust glyph point indices since each `.ttfautohint' subglyph shifts all following indices by one. This must be done for both the bytecode and one subformat of GPOS anchor tables. Back to my `great idea'. The Roboto font makes ttfautohint crash because I didn't consider the case that a composite glyph references an empty glyph. In this font, `nonbreakingspace' contains `space' as its only subglyph. But wait: What if I use this technique also? Bingo! The new code which I have been writing the last few days replaces the simple glyph `.ttfautohint' with a composite glyph, referencing an empty glyph. Doing so I can prepend the necessary bytecode to increase the counter while no contour gets added so that point indices stay the same. Very, very unfortunately this approach fails with FreeType, as I have discovered today: Due to a bug it executes bytecode only if there is at least one contour. Apparently noone has ever considered the construction which I envisioned while dozing... Maybe other engines implement a similar shortcut; I've asked this question on the OpenType list. Even if other TrueType engines handle this case correctly, I have to reject the new route because I can't expect that all applications which use FreeType immediately upgrade to the newest version. Anyway, 0.6.1 is coming soon (with point index shifts)! Werner ___ Freetype-devel mailing list Freetype-devel@nongnu.org https://lists.nongnu.org/mailman/listinfo/freetype-devel
Re: [ft-devel] ttfautohint 0.6 has been released
While testing google's new Roboto font (version 1.0), I found out that ttfautohint 0.6 crashes, unfortunately. Reason is the very weird glyph `nonbreakingspace' (its bbox is xMin=32767, yMin=32767, xMax=-32767, yMax=-32767, BTW) which is a composite glyph with a single component, namely `space'. However, `space' has no contours at all... Well, constructing such an anomaly is valid, but I haven't considered this case. Alas, it means a major redesign of some algorithms in ttfautohint. I'll release 0.6.1 after fixing this issue. Today in the morning, while still dozing, I had a great idea how to largely simplify hinting of composite glyphs, and which solves the Roboto issue at the same time. In particular, I believe that I've found a way to completely avoid fiddling with point indices. However, this means a lot of changes, so it will take a bit longer until 0.6.1 gets released. Note that 0.6.1 will have exactly the same functionality as 0.6; all modifications will be under the hood, not influencing the visible result. I ask you to test version 0.6 with fonts which don't make ttfautohint crash :-) In case you find a font which causes a segfault, or which causes bad rendering, or which makes font validation tools cry, please tell me the font's name so that I can test it later on. Werner ___ Freetype-devel mailing list Freetype-devel@nongnu.org https://lists.nongnu.org/mailman/listinfo/freetype-devel
Re: [ft-devel] ttfautohint 0.6 has been released
Could this be the same reason why 0.6 crashes for me on osx with a segmentation fault when autohinting any font? Of course not :-) What font have you tried? Werner ___ Freetype-devel mailing list Freetype-devel@nongnu.org https://lists.nongnu.org/mailman/listinfo/freetype-devel
Re: [ft-devel] ttfautohint 0.6 has been released
Could this be the same reason why 0.6 crashes for me on osx with a segmentation fault when autohinting any font? -v -Original message- From: Werner LEMBERG w...@gnu.org To: freetype-devel@nongnu.org Cc: roberts...@google.com, dcrossl...@google.com Sent: Tue, 27 Dec 2011, 06:29:50 GMT+00:00 Subject: Re: [ft-devel] ttfautohint 0.6 has been released ttfautohint 0.6 has been released. While testing google's new Roboto font (version 1.0), I found out that ttfautohint 0.6 crashes, unfortunately. Reason is the very weird glyph `nonbreakingspace' (its bbox is xMin=32767, yMin=32767, xMax=-32767, yMax=-32767, BTW) which is a composite glyph with a single component, namely `space'. However, `space' has no contours at all... Well, constructing such an anomaly is valid, but I haven't considered this case. Alas, it means a major redesign of some algorithms in ttfautohint. I'll release 0.6.1 after fixing this issue. Werner ___ Freetype-devel mailing list Freetype-devel@nongnu.org https://lists.nongnu.org/mailman/listinfo/freetype-devel ___ Freetype-devel mailing list Freetype-devel@nongnu.org https://lists.nongnu.org/mailman/listinfo/freetype-devel
Re: [ft-devel] ttfautohint 0.6 has been released
ttfautohint 0.6 has been released. While testing google's new Roboto font (version 1.0), I found out that ttfautohint 0.6 crashes, unfortunately. Reason is the very weird glyph `nonbreakingspace' (its bbox is xMin=32767, yMin=32767, xMax=-32767, yMax=-32767, BTW) which is a composite glyph with a single component, namely `space'. However, `space' has no contours at all... Well, constructing such an anomaly is valid, but I haven't considered this case. Alas, it means a major redesign of some algorithms in ttfautohint. I'll release 0.6.1 after fixing this issue. Werner ___ Freetype-devel mailing list Freetype-devel@nongnu.org https://lists.nongnu.org/mailman/listinfo/freetype-devel
[ft-devel] ttfautohint 0.6 has been released
ttfautohint 0.6 has been released. It is available from http://savannah.nongnu.org/download/freetype/ or http://sourceforge.net/projects/freetype/files/ttfautohint Merry Xmas! Werner PS: Downloads from savannah.nongnu.org will redirect to your nearest mirror site. Files on mirrors may be subject to a replication delay of up to 24 hours. In case of problems use http://download-mirror.savannah.gnu.org/releases/ -- This project provides a library which takes a TrueType font as the input, remove its bytecode instructions (if any), and return a new font where all glyphs are bytecode hinted using the information given by FreeType's autohinting module. The idea is to provide the excellent quality of the autohinter on platforms which don't use FreeType. The library has a single API function, `TTF_autohint'; see `src/ttfautohint.h' for a detailed description. Note that the library itself won't get installed currently. A simple command-line interface to the library is the demo program `ttfautohint'; after compilation and installation, say ttfautohint --help for usage information, or say man ttfautohint to read its manual page. = New in 0.6: * Improved handling of composite glyphs. * Implement option `-p' to pre-hint glyphs with original hints before conversion takes place. * Don't add a DSIG table if there is none in the input font. * Human-readable error messages instead of hexadecimal error codes. * Better tests (both at runtime and compile time) to reject too old FreeType versions. ___ Freetype-devel mailing list Freetype-devel@nongnu.org https://lists.nongnu.org/mailman/listinfo/freetype-devel
