RE: Transforming hmtx table

Hi Behdad,

The original MTX had pre-processing steps defined for hdmx and vdmx tables but I don’t think we did anything with hmtx. I remember Raph ran an estimate and concluded that hdmx/vdmx processing had ‘unfavorable’ gain /complexity ratio contributing little to overall compression so we decided to not have it as part of WOFF2 pre-processing step. I am not sure if we evaluated hmtx pre-processing at the same time, may be Raph can help to remember what, if anything, we considered w.r.t. hmtx table.

Cheers,
Vlad


From: Behdad Esfahbod [mailto:behdad@google.com]
Sent: Friday, April 24, 2015 2:30 AM
To: WOFF Working Group
Subject: Transforming hmtx table

Hi,

Has the working group considered transforming the hmtx table to remove the lsb field completely, if the lsb is the same as the xMin from glyf table for all glyphs?  That will save two bytes per glyph for TrueType fonts before Brotli compression.

behdad