On Sat, 2005-12-10 at 00:42, Werner LEMBERG wrote: > All of this looks very promising. I think the final decision on the > table format can only be done after converting a bunch of BDFs forth > and back. Ok. I have a version of fontforge which puts bdf properties into a 'BDF ' table in an sfnt, and then reads them back and writes them out into bdf. The data seem to survive the round trip.
I've posted a source tarball http://fontforge.sf.net/fontforge_full-20051213.tar.bz2 I've also posted an otb file containing 3 bitmap strikes and a BDF table http://fontforge.sf.net/hidden/FixedMedium.otb On Thu, 2005-12-08 at 16:46, Keith Packard wrote: > I need this + a utility to regenerate BDF files from the TTF so I can > validate a lossless round-trip for the existing BDF files. A couple of caveats about "lossless" round-trips: * BDF format supports an (x,y) advance for both horizontal & vertical metrics (ie. it could support Urdu where there is a vertical advance as well as horizontal) EBLC metrics only support one advance for each writing direction. hmtx/vmtx also only support one advance In other words for those rare fonts with an advance vector rather than a simple advance an otb font can't retain that info.(I don't think that's an issue for X) * BDF format supports advances, pixelsizes > 255 pixels EBLC metrics don't * FontForge doesn't really support VVector So this data will be lost (I don't think that's an issue for X) * Each otb file should be single resolution: X/BDF can distinguish between -gww-caslon-medium-r-normal--12-120-75-75-p-150-iso8859-1 -gww-caslon-medium-r-normal--12-100-100-100-p-150-iso8859-1 (same pixel size, but potentially different bitmap patterns because designed for different point-sizes at different resolutions) But EBLC can only have one strike per pixelsize. * If FontForge can't recognize the encoding of a font it doesn't know how to map glyphs into the cmap table. ===================================================================== I changed my BDF table proposal, taking out the idea of an array type and reverting to David's suggestion of treating them as atoms. So here is my current spec: /* Format: USHORT version : 'BDF' table version number, must be 0x0001 USHORT strikeCount : number of strikes in table ULONG stringTable : offset (from start of BDF table) to string table followed by an array of 'strikeCount' descriptors that look like: USHORT ppem : vertical pixels-per-EM for this strike USHORT num_items : number of items (properties and atoms), max is 255 this array is followed by 'strikeCount' value sets. Each "value set" is an array of (num_items) items that look like: ULONG item_name : offset in string table to item name USHORT item_type : item type: 0 => non-property string (e.g. COMMENT) 1 => non-property atom (e.g. FONT) (also SIZE even though not really an atom) 2 => non-property int32 3 => non-property uint32 0x10 => flag for a property, ored with above value types) ULONG item_value : item value. strings => an offset into the string table of the corresponding string, without the surrounding double-quotes atoms => an offset into the string table integers => the corresponding 32-bit value Then the string table of null terminated strings. These strings should be in ASCII. ================================================================== Comments? _______________________________________________ Fonts mailing list Fonts@XFree86.Org http://XFree86.Org/mailman/listinfo/fonts