[sfnt] Don't require 'gvar' table to support variation fonts.

Fixes #1172.

* src/sfnt/sfobjs.c (sfnt_load_face): Tag font as Multiple Masters font if
`fvar` is present; do not require other tables to be present.

* src/truetype/ttgxvar.c (tt_set_mm_blend): Allow for a missing 'gvar' table
when setting variation coordinates.  However, if a 'gvar' table is actually
present, do perform a sanity check and fail on malformedness.
(TT_Get_MM_Var): Don't assume 'fvar' needs 'gvar' or 'CFF2 tables in all
cases, which is an overly tight check.
This commit is contained in:
Dominik Röttsches 2022-08-19 19:07:42 +03:00 committed by Werner Lemberg
parent dd91f6e7f5
commit a1017e2655
2 changed files with 10 additions and 22 deletions

View File

@ -1107,13 +1107,7 @@
/* Don't bother to load the tables unless somebody asks for them. */
/* No need to do work which will (probably) not be used. */
if ( face->variation_support & TT_FACE_FLAG_VAR_FVAR )
{
if ( tt_face_lookup_table( face, TTAG_glyf ) != 0 &&
tt_face_lookup_table( face, TTAG_gvar ) != 0 )
flags |= FT_FACE_FLAG_MULTIPLE_MASTERS;
if ( tt_face_lookup_table( face, TTAG_CFF2 ) != 0 )
flags |= FT_FACE_FLAG_MULTIPLE_MASTERS;
}
flags |= FT_FACE_FLAG_MULTIPLE_MASTERS;
#endif
root->face_flags = flags;

View File

@ -2217,20 +2217,6 @@
{
FT_TRACE2(( "FVAR " ));
/* both `fvar' and `gvar' must be present */
if ( FT_SET_ERROR( face->goto_table( face, TTAG_gvar,
stream, &table_len ) ) )
{
/* CFF2 is an alternate to gvar here */
if ( FT_SET_ERROR( face->goto_table( face, TTAG_CFF2,
stream, &table_len ) ) )
{
FT_TRACE1(( "\n" ));
FT_TRACE1(( "TT_Get_MM_Var: `gvar' or `CFF2' table is missing\n" ));
goto Exit;
}
}
if ( FT_SET_ERROR( face->goto_table( face, TTAG_fvar,
stream, &table_len ) ) )
{
@ -2673,8 +2659,16 @@
FT_TRACE5(( "\n" ));
if ( !face->is_cff2 && !blend->glyphoffsets )
if ( FT_SET_ERROR( ft_var_load_gvar( face ) ) )
{
/* While a missing 'gvar' table is acceptable, for example for */
/* fonts that only vary metrics information or 'COLR' v1 */
/* `PaintVar*` tables, an incorrect SFNT table offset or size */
/* for 'gvar', or an inconsistent 'gvar' table is not. */
error = ft_var_load_gvar( face );
if ( error != FT_Err_Table_Missing && error != FT_Err_Ok )
goto Exit;
error = FT_Err_Ok;
}
if ( !blend->coords )
{