ref: ac4c1ebf7edb3c142c5c4ad9b3345d95325750fd
parent: 907715a6a214001db7504983f6cf2a48e8b33053
author: Werner Lemberg <[email protected]>
date: Mon Feb 7 01:55:54 EST 2022
[truetype] Fix 'sbix' table handling. * src/sfnt/ttsbit.c (tt_face_load_sbix_image): Correct calculation of 'metrics->horiBearingY'. Set vertical metrics. * src/sfnt/sfobjs.c (sfnt_load_face): Adjust setting of `FT_FACE_FLAG_SBIX`. Handle metrics of fonts with 'sbix' table. * src/truetype/ttgload.c (TT_Load_Glyph): For 'sbix' embedded bitmaps, apply bbox offset and bearing values of the corresponding glyph in the 'glyf' table if it exists and has a contour. * src/truetype/ttobjs.c (tt_face_init): Handle font with 'sbix' table. Fixes issue #998.
--- a/src/sfnt/sfobjs.c
+++ b/src/sfnt/sfobjs.c
@@ -851,12 +851,6 @@
is_apple_sbit = 0;
is_apple_sbix = !face->goto_table( face, TTAG_sbix, stream, 0 );
- /* Apple 'sbix' color bitmaps are rendered scaled and then the 'glyf'
- * outline rendered on top. We don't support that yet, so just ignore
- * the 'glyf' outline and advertise it as a bitmap-only font. */
- if ( is_apple_sbix )
- has_outline = FALSE;
-
/* if this font doesn't contain outlines, we try to load */
/* a `bhed' table */
if ( !has_outline && sfnt->load_bhed )
@@ -1059,10 +1053,12 @@
if ( has_outline == TRUE )
{- flags |= FT_FACE_FLAG_SCALABLE; /* scalable outlines */
-
- if ( face->sbit_table_type == TT_SBIT_TABLE_TYPE_SBIX )
- flags |= FT_FACE_FLAG_SBIX; /* and 'sbix' bitmaps */
+ /* by default (and for backward compatibility) we handle */
+ /* fonts with an 'sbix' table as bitmap-only */
+ if ( is_apple_sbix )
+ flags |= FT_FACE_FLAG_SBIX; /* with 'sbix' bitmaps */
+ else
+ flags |= FT_FACE_FLAG_SCALABLE; /* scalable outlines */
}
/* The sfnt driver only supports bitmap fonts natively, thus we */
@@ -1286,7 +1282,8 @@
*
* Set up metrics.
*/
- if ( FT_IS_SCALABLE( root ) )
+ if ( FT_IS_SCALABLE( root ) ||
+ FT_HAS_SBIX( root ) )
{/* XXX What about if outline header is missing */
/* (e.g. sfnt wrapped bitmap)? */
--- a/src/sfnt/ttsbit.c
+++ b/src/sfnt/ttsbit.c
@@ -1580,7 +1580,7 @@
if ( !error )
{- FT_Short abearing;
+ FT_Short abearing; /* not used here */
FT_UShort aadvance;
@@ -1587,8 +1587,25 @@
tt_face_get_metrics( face, FALSE, glyph_index, &abearing, &aadvance );
metrics->horiBearingX = (FT_Short)originOffsetX;
- metrics->horiBearingY = (FT_Short)( -originOffsetY + metrics->height );
+ metrics->vertBearingX = (FT_Short)originOffsetX;
+
+ metrics->horiBearingY = (FT_Short)( originOffsetY + metrics->height );
+ metrics->vertBearingY = (FT_Short)originOffsetY;
+
metrics->horiAdvance = (FT_UShort)( aadvance *
+ face->root.size->metrics.x_ppem /
+ face->header.Units_Per_EM );
+
+ if ( face->vertical_info )
+ tt_face_get_metrics( face, TRUE, glyph_index, &abearing, &aadvance );
+ else if ( face->os2.version != 0xFFFFU )
+ aadvance = (FT_UShort)FT_ABS( face->os2.sTypoAscender -
+ face->os2.sTypoDescender );
+ else
+ aadvance = (FT_UShort)FT_ABS( face->horizontal.Ascender -
+ face->horizontal.Descender );
+
+ metrics->vertAdvance = (FT_UShort)( aadvance *
face->root.size->metrics.x_ppem /
face->header.Units_Per_EM );
}
--- a/src/truetype/ttgload.c
+++ b/src/truetype/ttgload.c
@@ -2897,8 +2897,12 @@
}
else
{- if ( FT_IS_SCALABLE( glyph->face ) )
+ if ( FT_IS_SCALABLE( glyph->face ) ||
+ FT_HAS_SBIX( glyph->face ) )
{+ TT_Face face = (TT_Face)glyph->face;
+
+
/* for the bbox we need the header only */
(void)tt_loader_init( &loader, size, glyph, load_flags, TRUE );
(void)load_truetype_glyph( &loader, glyph_index, 0, TRUE );
@@ -2905,6 +2909,35 @@
tt_loader_done( &loader );
glyph->linearHoriAdvance = loader.linear;
glyph->linearVertAdvance = loader.vadvance;
+
+ /* Bitmaps from the 'sbix' table need special treatment: */
+ /* if there is a glyph contour, the bitmap origin must be */
+ /* shifted to be relative to the lower left corner of the */
+ /* glyph bounding box, also taking the left-side bearing */
+ /* (or top bearing) into account. */
+ if ( face->sbit_table_type == TT_SBIT_TABLE_TYPE_SBIX &&
+ loader.n_contours > 0 )
+ {+ FT_Int bitmap_left;
+ FT_Int bitmap_top;
+
+
+ if ( load_flags & FT_LOAD_VERTICAL_LAYOUT )
+ {+ /* This is a guess, since Apple's CoreText engine doesn't */
+ /* really do vertical typesetting. */
+ bitmap_left = loader.bbox.xMin;
+ bitmap_top = loader.top_bearing;
+ }
+ else
+ {+ bitmap_left = loader.left_bearing;
+ bitmap_top = loader.bbox.yMin;
+ }
+
+ glyph->bitmap_left += FT_MulFix( bitmap_left, x_scale ) >> 6;
+ glyph->bitmap_top += FT_MulFix( bitmap_top, y_scale ) >> 6;
+ }
/* sanity checks: if `xxxAdvance' in the sbit metric */
/* structure isn't set, use `linearXXXAdvance' */
--- a/src/truetype/ttobjs.c
+++ b/src/truetype/ttobjs.c
@@ -727,7 +727,8 @@
if ( error )
goto Exit;
- if ( FT_IS_SCALABLE( ttface ) )
+ if ( FT_IS_SCALABLE( ttface ) ||
+ FT_HAS_SBIX( ttface ) )
{#ifdef FT_CONFIG_OPTION_INCREMENTAL
if ( !ttface->internal->incremental_interface )