- From: Thomas Phinney <tphinney@cal.berkeley.edu>
- Date: Tue, 30 Jun 2009 00:16:03 -0500
- To: John Daggett <jdaggett@mozilla.com>
- Cc: www-font@w3.org
Hmmm. Hard to make suggestions without knowing what all you have access to. Let's discuss off-list... Regards, T On Mon, Jun 29, 2009 at 11:56 PM, John Daggett<jdaggett@mozilla.com> wrote: > > Hi Thomas, > > Any examples you would suggest? > > Cheers, > > John > > ----- Original Message ----- > From: "Thomas Phinney" <tphinney@cal.berkeley.edu> > To: "John Daggett" <jdaggett@mozilla.com> > Cc: www-font@w3.org, "Philippe Le Hegaret" <plh@w3.org>, "chris" <chris@w3.org>, "Vladimir Levantovsky" <Vladimir.Levantovsky@monotypeimaging.com> > Sent: Tuesday, June 30, 2009 1:45:46 PM GMT +09:00 Japan > Subject: Re: gzip vs. mtx compression ratios > > That's quite interesting. But for general fonts in the wild, neither > system fonts nor the ClearType C-fonts are very representative. They > are all hand-hinted, which makes them unlike 99% of TrueType fonts out > there. > > It would be interesting to see the results on some typical TrueType > fonts that have been autohinted by (1) Fontographer 4.x and (2) > FontLab Studio 5. That would tell us a bit more. > > Regards, > > T > > On Mon, Jun 29, 2009 at 2:05 AM, John Daggett<jdaggett@mozilla.com> wrote: >> I sat down a little today and played around with font compression. I >> tested compression ratios of gzip vs. MTX, the MicroType Express >> algorithm used as part of the Microsoft EOT format. The spreadsheet >> below contains charts and a summary of the data I collected: >> >> https://spreadsheets.google.com/ccc?key=rKT_wNzraVrkXQcKSWb-jTA&hl=en >> >> I used Microsoft's WEFT tool to create unsubsetted EOT versions of each >> font and compared it with the gzip-compressed version of the font file. >> >> As Vlad noted before, standard webfonts such as Times New Roman, Arial, >> Georgia and Verdana compress to file sizes 20-28% smaller than the size >> of files compressed with gzip. However, fonts in the Cleartype font set >> that Microsoft commissioned for Vista are only 11-14% smaller. These >> fonts use less hinting than traditional TrueType fonts and rely on >> Cleartype screen rendering to render glyphs clearly. This is important >> because it seems indicative of a trend towards more lightly hinted >> TrueType fonts, which would indicate the hint-related compression that >> MTX provides won't be needed as much going forward. But MTX for these >> fonts still does a better job than plain gzip compression. >> >> For large CJK fonts however, where compression is most needed, MTX >> doesn't provide much beyond straight gzip compression. For Meiryo, EOT >> files are 17% smaller but for other CJK fonts the range was only 2-12%. >> In fact, using bzip2 general compression beat font-specific MTX for >> several of these fonts. These numbers are also probably distorted in >> favor of MTX because the fonts were in TrueType collection files (.ttc) >> rather than straight .ttf files, so there are extra glyphs in the gzip >> file that aren't in the EOT version. >> >> Since the WEFT tool doesn't handle Postscript CFF fonts (.otf) >> currently, I tested the MTX compression of these fonts by merging CFF >> data from other .otf fonts into a TrueType font, then comparing the >> differences in the resulting compressed versions. The MTX compression >> seemed to be around 5% better than straight gzip. Although this doesn't >> account for compressed metrics, I think this is pretty close to the >> compression that a version of MTX modified to compress CFF glyph data >> would see. >> >> In summary, MTX seems to compress older TrueType fonts well but less so >> more modern lightly-hinted fonts. It is a little bit better than gzip >> for CJK fonts but lags behind general bzip2 compression in many >> instances. For .otf fonts it's only slightly better than gzip >> compression. >> >> Regards, >> >> John Daggett >> Mozilla Japan >> >> > > > > -- > "Men occasionally stumble over the truth, but most of them pick themselves up > and hurry off as if nothing ever happened." > - Sir Winston Churchill > -- "Men occasionally stumble over the truth, but most of them pick themselves up and hurry off as if nothing ever happened." - Sir Winston Churchill
Received on Tuesday, 30 June 2009 05:16:40 UTC