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[truetype] Fix linear metrics of GX variation fonts. 

When asking for an unhinted non-default variations,
`linearVertAdvance' is currently the value from the `hmtx' table
instead of the actual value after applying the variation.  `HVAR'
support fixes this, but fonts will exist without that table and will
need sane fallback.

* src/truetype/ttgload.c (TT_Process_Simple_Glyph,
load_truetype_glyph): Implement linear advance adjustments if `HVAR'
or `VVAR' tables are missing.
This commit is contained in:
Ben Wagner 2016-12-20 11:37:42 +01:00 committed by Werner Lemberg
parent a1e85f11c8
commit cc576f8002
2 changed files with 61 additions and 0 deletions
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15
ChangeLog
View File

@ -1,3 +1,18 @@
2016-12-20 Ben Wagner <bungeman@google.com>
Werner Lemberg <wl@gnu.org>
[truetype] Fix linear metrics of GX variation fonts.
When asking for an unhinted non-default variations,
`linearVertAdvance' is currently the value from the `hmtx' table
instead of the actual value after applying the variation. `HVAR'
support fixes this, but fonts will exist without that table and will
need sane fallback.
* src/truetype/ttgload.c (TT_Process_Simple_Glyph,
load_truetype_glyph): Implement linear advance adjustments if `HVAR'
or `VVAR' tables are missing.
2016-12-20 Werner Lemberg <wl@gnu.org>
[cff, truetype] Fast advance width retrieval for fonts with HVAR.

46
src/truetype/ttgload.c
View File

@ -888,11 +888,25 @@
if ( loader->face->doblend && !loader->face->is_default_instance )
{
FT_Service_MetricsVariations var =
(FT_Service_MetricsVariations)loader->face->var;
/* Deltas apply to the unscaled data. */
error = TT_Vary_Apply_Glyph_Deltas( loader->face,
loader->glyph_index,
outline,
(FT_UInt)n_points );
/* recalculate linear horizontal and vertical advances */
/* if we don't have HVAR and VVAR, respectively */
if ( !( var && var->hadvance_adjust ) )
loader->linear = outline->points[n_points - 3].x -
outline->points[n_points - 4].x;
if ( !( var && var->vadvance_adjust ) )
loader->vadvance = outline->points[n_points - 1].x -
outline->points[n_points - 2].x;
if ( error )
return error;
}
@ -1566,6 +1580,10 @@
if ( loader->face->doblend && !loader->face->is_default_instance )
{
FT_Service_MetricsVariations var =
(FT_Service_MetricsVariations)loader->face->var;
/* a small outline structure with four elements for */
/* communication with `TT_Vary_Apply_Glyph_Deltas' */
FT_Vector points[4];
@ -1607,6 +1625,14 @@
loader->pp3.y = points[2].y;
loader->pp4.x = points[3].x;
loader->pp4.y = points[3].y;
/* recalculate linear horizontal and vertical advances */
/* if we don't have HVAR and VVAR, respectively */
if ( !( var && var->hadvance_adjust ) )
loader->linear = loader->pp2.x - loader->pp1.x;
if ( !( var && var->vadvance_adjust ) )
loader->vadvance = loader->pp4.x - loader->pp3.x;
}
#endif /* TT_CONFIG_OPTION_GX_VAR_SUPPORT */
@ -1729,6 +1755,10 @@
if ( face->doblend && !face->is_default_instance )
{
FT_Service_MetricsVariations var =
(FT_Service_MetricsVariations)face->var;
short i, limit;
FT_SubGlyph subglyph;
@ -1824,6 +1854,13 @@
loader->pp4.x = points[i + 3].x;
loader->pp4.y = points[i + 3].y;
/* recalculate linear horizontal and vertical advances */
/* if we don't have HVAR and VVAR, respectively */
if ( !( var && var->hadvance_adjust ) )
loader->linear = loader->pp2.x - loader->pp1.x;
if ( !( var && var->vadvance_adjust ) )
loader->vadvance = loader->pp4.x - loader->pp3.x;
Exit1:
FT_FREE( outline.points );
FT_FREE( outline.tags );
@ -1883,6 +1920,9 @@
{
FT_Vector pp[4];
FT_Int linear_hadvance;
FT_Int linear_vadvance;
/* Each time we call load_truetype_glyph in this loop, the */
/* value of `gloader.base.subglyphs' can change due to table */
@ -1895,6 +1935,9 @@
pp[2] = loader->pp3;
pp[3] = loader->pp4;
linear_hadvance = loader->linear;
linear_vadvance = loader->vadvance;
num_base_points = (FT_UInt)gloader->base.outline.n_points;
error = load_truetype_glyph( loader,
@ -1914,6 +1957,9 @@
loader->pp2 = pp[1];
loader->pp3 = pp[2];
loader->pp4 = pp[3];
loader->linear = linear_hadvance;
loader->vadvance = linear_vadvance;
}
num_points = (FT_UInt)gloader->base.outline.n_points;