[Git][freetype/freetype][master] [woff2] Support overlap flag for simple glyphs.

[Werner Lemberg (@wl)]

Werner Lemberg pushed to branch master at FreeType / FreeType

Commits:

• a960be9e
  by Ben Wagner at 2022-03-20T07:27:43+00:00

  [woff2] Support overlap flag for simple glyphs.
  
  In the woff2 spec it has been proposed to allow the OVERLAP_SIMPLE flag
  to be retained through the woff2 format [0].
  
  [0] https://www.w3.org/TR/WOFF2/#glyf_table_format
  
  * src/sfnt/sfwoff2.h (GLYF_OVERLAP_SIMPLE): add glyf flag.
  
  * src/sfnt/sfwoff2.c (reconstruct_glyf): parse optionFlags and
  overlapSimpleBitmap[]. (store_points): set OVERLAP_SIMPLE on first point's
  flag if the overlap bit is set.
  

2 changed files:

• src/sfnt/sfwoff2.c
• src/sfnt/sfwoff2.h

Changes:

src/sfnt/sfwoff2.c

---

...	...	@@ -84,6 +84,8 @@
84	84	#define BBOX_STREAM 5
85	85	#define INSTRUCTION_STREAM 6
86	86
	87	+#define HAVE_OVERLAP_SIMPLE_BITMAP 0x1
	88	+
87	89
88	90	static void
89	91	stream_close( FT_Stream stream )
...	...	@@ -522,6 +524,7 @@
522	524	const WOFF2_Point points,
523	525	FT_UShort n_contours,
524	526	FT_UShort instruction_len,
	527	+ FT_Bool have_overlap,
525	528	FT_Byte* dst,
526	529	FT_ULong dst_size,
527	530	FT_ULong* glyph_size )
...	...	@@ -549,6 +552,9 @@
549	552	FT_Int dy = point.y - last_y;
550	553
551	554
	555	+ if ( i == 0 && have_overlap )
	556	+ flag |= GLYF_OVERLAP_SIMPLE;
	557	+
552	558	if ( dx == 0 )
553	559	flag |= GLYF_THIS_X_IS_SAME;
554	560	else if ( dx > -256 && dx < 256 )
...	...	@@ -833,15 +839,18 @@
833	839
834	840	FT_UInt num_substreams = 7;
835	841
	842	+ FT_UShort option_flags;
836	843	FT_UShort num_glyphs;
837	844	FT_UShort index_format;
838	845	FT_ULong expected_loca_length;
839	846	FT_UInt offset;
840	847	FT_UInt i;
841	848	FT_ULong points_size;
842		- FT_ULong bitmap_length;
843	849	FT_ULong glyph_buf_size;
844	850	FT_ULong bbox_bitmap_offset;
	851	+ FT_ULong bbox_bitmap_length;
	852	+ FT_ULong overlap_bitmap_offset = 0;
	853	+ FT_ULong overlap_bitmap_length = 0;
845	854
846	855	const FT_ULong glyf_start = *out_offset;
847	856	FT_ULong dest_offset = *out_offset;
...	...	@@ -857,15 +866,17 @@
857	866	if ( FT_NEW_ARRAY( substreams, num_substreams ) )
858	867	goto Fail;
859	868
860		- if ( FT_STREAM_SKIP( 4 ) )
	869	+ if ( FT_STREAM_SKIP( 2 ) )
	870	+ goto Fail;
	871	+ if ( FT_READ_USHORT( option_flags ) )
861	872	goto Fail;
862	873	if ( FT_READ_USHORT( num_glyphs ) )
863	874	goto Fail;
864	875	if ( FT_READ_USHORT( index_format ) )
865	876	goto Fail;
866	877
867		- FT_TRACE4(( "num_glyphs = %u; index_format = %u\n",
868		- num_glyphs, index_format ));
	878	+ FT_TRACE4(( "option_flags = %u; num_glyphs = %u; index_format = %u\n",
	879	+ option_flags, num_glyphs, index_format ));
869	880
870	881	info->num_glyphs = num_glyphs;
871	882
...	...	@@ -878,7 +889,7 @@
878	889	if ( info->loca_table->dst_length != expected_loca_length )
879	890	goto Fail;
880	891
881		- offset = ( 2 + num_substreams ) * 4;
	892	+ offset = 2 + 2 + 2 + 2 + ( num_substreams * 4 );
882	893	if ( offset > info->glyf_table->TransformLength )
883	894	goto Fail;
884	895
...	...	@@ -901,6 +912,20 @@
901	912	offset += substream_size;
902	913	}
903	914
	915	+ if ( option_flags & HAVE_OVERLAP_SIMPLE_BITMAP )
	916	+ {
	917	+ /* Size of overlapBitmap = floor((numGlyphs + 7) / 8) */
	918	+ overlap_bitmap_length = ( num_glyphs + 7U ) >> 3;
	919	+ if ( overlap_bitmap_length > info->glyf_table->TransformLength - offset )
	920	+ goto Fail;
	921	+
	922	+ overlap_bitmap_offset = pos + offset;
	923	+
	924	+ FT_TRACE5(( " Overlap bitmap: offset = %lu; size = %lu;\n",
	925	+ overlap_bitmap_offset, overlap_bitmap_length ));
	926	+ offset += overlap_bitmap_length;
	927	+ }
	928	+
904	929	if ( FT_NEW_ARRAY( loca_values, num_glyphs + 1 ) )
905	930	goto Fail;
906	931
...	...	@@ -908,8 +933,9 @@
908	933	bbox_bitmap_offset = substreams[BBOX_STREAM].offset;
909	934
910	935	/* Size of bboxBitmap = 4 * floor((numGlyphs + 31) / 32) */
911		- bitmap_length = ( ( num_glyphs + 31U ) >> 5 ) << 2;
912		- substreams[BBOX_STREAM].offset += bitmap_length;
	936	+ bbox_bitmap_length = ( ( num_glyphs + 31U ) >> 5 ) << 2;
	937	+ /* bboxStreamSize is the combined size of bboxBitmap and bboxStream. */
	938	+ substreams[BBOX_STREAM].offset += bbox_bitmap_length;
913	939
914	940	glyph_buf_size = WOFF2_DEFAULT_GLYPH_BUF;
915	941	if ( FT_NEW_ARRAY( glyph_buf, glyph_buf_size ) )
...	...	@@ -1025,8 +1051,11 @@
1025	1051	FT_ULong flag_size;
1026	1052	FT_ULong triplet_size;
1027	1053	FT_ULong triplet_bytes_used;
1028		- FT_Byte* flags_buf = NULL;
1029		- FT_Byte* triplet_buf = NULL;
	1054	+ FT_Bool have_overlap = FALSE;
	1055	+ FT_Byte overlap_bitmap;
	1056	+ FT_ULong overlap_offset;
	1057	+ FT_Byte* flags_buf = NULL;
	1058	+ FT_Byte* triplet_buf = NULL;
1030	1059	FT_UShort instruction_size;
1031	1060	FT_ULong size_needed;
1032	1061	FT_Int end_point;
...	...	@@ -1035,6 +1064,17 @@
1035	1064	FT_Byte* pointer = NULL;
1036	1065
1037	1066
	1067	+ /* Set `have_overlap`. */
	1068	+ if ( overlap_bitmap_offset )
	1069	+ {
	1070	+ overlap_offset = overlap_bitmap_offset + ( i >> 3 );
	1071	+ if ( FT_STREAM_SEEK( overlap_offset ) ||
	1072	+ FT_READ_BYTE( overlap_bitmap ) )
	1073	+ goto Fail;
	1074	+ if ( overlap_bitmap & ( 0x80 >> ( i & 7 ) ) )
	1075	+ have_overlap = TRUE;
	1076	+ }
	1077	+
1038	1078	if ( FT_NEW_ARRAY( n_points_arr, n_contours ) )
1039	1079	goto Fail;
1040	1080
...	...	@@ -1155,6 +1195,7 @@
1155	1195	points,
1156	1196	n_contours,
1157	1197	instruction_size,
	1198	+ have_overlap,
1158	1199	glyph_buf,
1159	1200	glyph_buf_size,
1160	1201	&glyph_size ) )

src/sfnt/sfwoff2.h

---

...	...	@@ -56,6 +56,7 @@ FT_BEGIN_HEADER
56	56	#define GLYF_REPEAT 1 << 3
57	57	#define GLYF_THIS_X_IS_SAME 1 << 4
58	58	#define GLYF_THIS_Y_IS_SAME 1 << 5
	59	+#define GLYF_OVERLAP_SIMPLE 1 << 6
59	60
60	61	/* Other constants */
61	62	#define CONTOUR_OFFSET_END_POINT 10

—
View it on GitLab.
You're receiving this email because of your account on gitlab.freedesktop.org. If you'd like to receive fewer emails, you can adjust your notification settings.