Hi Behdad, On Wed, 2012-11-14 at 12:01 -0800, Behdad Esfahbod wrote: > I reiterate what I've said many many times on this list already. Hopefully > this puts an end to this particular topic. More below.
Are you referring to your mantra, "I consider the fonts broken if they don't work with Uniscribe." ? > On 12-11-13 06:15 PM, Harshula wrote: > > Hi Behdad & Jonathan, > > > > On Tue, 2012-11-13 at 12:40 -0800, Behdad Esfahbod wrote: > >> Jonathan and I decided to workaround the Sinhala issue with split matras > >> and > >> free fonts, such that they continue working with new HarfBuzz. That's in > >> master now. > > > > 1) GNU Free Font maintainer, Steve, went to a lot of effort to make > > FreeSerif work with Uniscribe and the Harfbuzz behaviour we agreed to in > > September. > > (http://lists.freedesktop.org/archives/harfbuzz/2012-September/002458.html). > > See SVN version of FreeSerif. He is also working hard to do a release soon. > > Good that he did. Because in general we don't care about supporting fonts > that are broken with Uniscribe. That contradicts the intent of Commit 0736915b8ed789a209205fec762997af3a8af89c ([Indic] Decompose Sinhala split matras the way old HarfBuzz / Pango did). So what makes this an exception to the rule? In practice, this Commit adds support for 1 font that is incompatible with Uniscribe that I no longer maintain. > > 2) You refer to "free fonts". Are you referring to GNU Free Font or to > > the two GPL'd fonts that support Sinhala? One of them is deprecated, > > there are problems with glyphs etc, and the other, FreeSerif, that is > > meant to replace the former works well with Harfbuzz from a week ago. > > I meant fonts that were designed to work with the Free Software shaping > engines (old HarfBuzz, Pango, ICU LayoutEngine). There are two such fonts. One of which is deprecated and I've stopped maintaining it. So you've fixed a 'problem' that doesn't exist once the next release of FreeFont ships. > > 3) The big win, from the behaviour agreed to in September, is that any > > Windows font will just work with Harfbuzz. With the FreeSerif changes, > > that meant that all maintained fonts just work. From the perspective of > > actual Linux Sinhala script users, that increases their font options > > significantly. > > What we decided to do yesterday allows for both set of fonts to work with > harfbuzz-ng. This is a superset of the fonts that HarfBuzz before yesterday > could render correctly, and a superset of fonts that worked with old HarfBuzz > / Pango, and a superset of fonts that work with Uniscribe. So it can't be > worse. How exactly is an end-user, for example using GNOME 3.6, going to be able to use a superset of fonts if Harfbuzz needs an environment flag HB_OT_INDIC_OPTIONS=uniscribe-bug-compatible in-order for fonts made for Uniscribe to work? When the flag is *set* or *not set*, under each of these conditions only a strict subset will work. How can a superset of fonts work at the same time? I'd be very happy if an end-user could use a superset of fonts encompassing those made for Pango/ICU and Uniscribe with Harfbuzz. But that does not appear to be the case in reality. > > 4) Commit 0736915b8ed789a209205fec762997af3a8af89c ([Indic] Decompose > > Sinhala split matras the way old HarfBuzz / Pango did) has a bug. The > > five fonts I test with do not render correctly now. I suspect no fonts > > render correctly with current TOT Harfbuzz. i.e. A regression. Try කේ > > (<U+0d9a><U+0dda>). > > Ouch. Fix pushed out. We will make another release at the end of the week. Tested. Harfbuzz at least now works for some Sinhala fonts. Thanks. > > 5) Since this is a FOSS project, any chance you and Jonathon could > > elaborate a bit on the problem you guys are trying to fix and the > > reasoning behind the decision to overturn what was agreed to in > > September? > > I already explained the problem in response to your email back in July: > > http://lists.freedesktop.org/archives/harfbuzz/2012-July/002261.html That was 25 July 2012, you said: ------------------------------------------ "The new shaper follows Uniscribe here. You can disable that by removing a few lines from hb-unicode.cc. Just search for DDC. That would make the new shaper match HarfBuzz-old. Though, I consider the fonts broken if they don't work with Uniscribe. So, in this particular case, it may make sense to limit the Uniscribe behavior to the uniscribe-bug-compatibilty mode. Jonathan, what do you think?" ------------------------------------------ You nor Jonathan responded to that email to indicate the direction you had decided. So I followed it up on 3 September 2012 (http://lists.freedesktop.org/archives/harfbuzz/2012-September/002450.html) to which you responded (http://lists.freedesktop.org/archives/harfbuzz/2012-September/002458.html): ------------------------------------------ > I have been considering this conundrum and here are my thoughts: > > 1) Ideally any Unicode Sinhala font that 'works' with Uniscribe should > just 'work' on GNU/Linux. Correct. That will be the case with new HarfBuzz Indic shaper. > 2) I tested a few freely (cost) available fonts that used to be or are > now reference fonts. Two of these work correctly with both the *new* and > *old* shapers. It's definitely possible to develop a font that works with both. > 3) Taking (2) into account, it may be possible for existing GNU/Linux > fonts to support both the new and old shaper. However, I would have to > defer that to someone who knows their way around fonts better. When you find someone who wants to fix the font, let me know and I can tell them exactly what to do. > 4) The way Uniscribe has implemented this is a bit unexpected, what > happens if Uniscribe changes/fixes this? Do we just blindly follow > Uniscribe? In absence of any standard, yes. That said, Microsoft has never changed those kinds of things in a way that would break things. behdad ------------------------------------------ Hence, in September you clearly communicated that HarfBuzz intends to follow Uniscribe's behaviour on this issue. However, in November without any communication you committed a patch that overturned that decision. You've set a rule for Harfbuzz, that you have repeated a number of times, that you consider fonts that do not work with Uniscribe to be broken. In this case you have made an exception to your own rule for a font that is deprecated and I no longer maintain. Can you please explain why? I am advocating that the Uniscribe behaviour be retained in Harfbuzz on this issue as it was one week ago. By the lack of transparency, in particular not communicating/discussing direction changes, you are making it harder for those trying to support HarfBuzz. As HarfBuzz is more widely deployed, this will become a bigger problem. cya, # _______________________________________________ HarfBuzz mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/harfbuzz
