[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.
This commit is contained in:
Ben Wagner 2022-03-18 17:41:01 -04:00 committed by Werner Lemberg
parent d2c3bbcd8e
commit a960be9e5e
2 changed files with 51 additions and 9 deletions

View File

@ -84,6 +84,8 @@
#define BBOX_STREAM 5 #define BBOX_STREAM 5
#define INSTRUCTION_STREAM 6 #define INSTRUCTION_STREAM 6
#define HAVE_OVERLAP_SIMPLE_BITMAP 0x1
static void static void
stream_close( FT_Stream stream ) stream_close( FT_Stream stream )
@ -522,6 +524,7 @@
const WOFF2_Point points, const WOFF2_Point points,
FT_UShort n_contours, FT_UShort n_contours,
FT_UShort instruction_len, FT_UShort instruction_len,
FT_Bool have_overlap,
FT_Byte* dst, FT_Byte* dst,
FT_ULong dst_size, FT_ULong dst_size,
FT_ULong* glyph_size ) FT_ULong* glyph_size )
@ -549,6 +552,9 @@
FT_Int dy = point.y - last_y; FT_Int dy = point.y - last_y;
if ( i == 0 && have_overlap )
flag |= GLYF_OVERLAP_SIMPLE;
if ( dx == 0 ) if ( dx == 0 )
flag |= GLYF_THIS_X_IS_SAME; flag |= GLYF_THIS_X_IS_SAME;
else if ( dx > -256 && dx < 256 ) else if ( dx > -256 && dx < 256 )
@ -833,15 +839,18 @@
FT_UInt num_substreams = 7; FT_UInt num_substreams = 7;
FT_UShort option_flags;
FT_UShort num_glyphs; FT_UShort num_glyphs;
FT_UShort index_format; FT_UShort index_format;
FT_ULong expected_loca_length; FT_ULong expected_loca_length;
FT_UInt offset; FT_UInt offset;
FT_UInt i; FT_UInt i;
FT_ULong points_size; FT_ULong points_size;
FT_ULong bitmap_length;
FT_ULong glyph_buf_size; FT_ULong glyph_buf_size;
FT_ULong bbox_bitmap_offset; FT_ULong bbox_bitmap_offset;
FT_ULong bbox_bitmap_length;
FT_ULong overlap_bitmap_offset = 0;
FT_ULong overlap_bitmap_length = 0;
const FT_ULong glyf_start = *out_offset; const FT_ULong glyf_start = *out_offset;
FT_ULong dest_offset = *out_offset; FT_ULong dest_offset = *out_offset;
@ -857,15 +866,17 @@
if ( FT_NEW_ARRAY( substreams, num_substreams ) ) if ( FT_NEW_ARRAY( substreams, num_substreams ) )
goto Fail; goto Fail;
if ( FT_STREAM_SKIP( 4 ) ) if ( FT_STREAM_SKIP( 2 ) )
goto Fail;
if ( FT_READ_USHORT( option_flags ) )
goto Fail; goto Fail;
if ( FT_READ_USHORT( num_glyphs ) ) if ( FT_READ_USHORT( num_glyphs ) )
goto Fail; goto Fail;
if ( FT_READ_USHORT( index_format ) ) if ( FT_READ_USHORT( index_format ) )
goto Fail; goto Fail;
FT_TRACE4(( "num_glyphs = %u; index_format = %u\n", FT_TRACE4(( "option_flags = %u; num_glyphs = %u; index_format = %u\n",
num_glyphs, index_format )); option_flags, num_glyphs, index_format ));
info->num_glyphs = num_glyphs; info->num_glyphs = num_glyphs;
@ -878,7 +889,7 @@
if ( info->loca_table->dst_length != expected_loca_length ) if ( info->loca_table->dst_length != expected_loca_length )
goto Fail; goto Fail;
offset = ( 2 + num_substreams ) * 4; offset = 2 + 2 + 2 + 2 + ( num_substreams * 4 );
if ( offset > info->glyf_table->TransformLength ) if ( offset > info->glyf_table->TransformLength )
goto Fail; goto Fail;
@ -901,6 +912,20 @@
offset += substream_size; offset += substream_size;
} }
if ( option_flags & HAVE_OVERLAP_SIMPLE_BITMAP )
{
/* Size of overlapBitmap = floor((numGlyphs + 7) / 8) */
overlap_bitmap_length = ( num_glyphs + 7U ) >> 3;
if ( overlap_bitmap_length > info->glyf_table->TransformLength - offset )
goto Fail;
overlap_bitmap_offset = pos + offset;
FT_TRACE5(( " Overlap bitmap: offset = %lu; size = %lu;\n",
overlap_bitmap_offset, overlap_bitmap_length ));
offset += overlap_bitmap_length;
}
if ( FT_NEW_ARRAY( loca_values, num_glyphs + 1 ) ) if ( FT_NEW_ARRAY( loca_values, num_glyphs + 1 ) )
goto Fail; goto Fail;
@ -908,8 +933,9 @@
bbox_bitmap_offset = substreams[BBOX_STREAM].offset; bbox_bitmap_offset = substreams[BBOX_STREAM].offset;
/* Size of bboxBitmap = 4 * floor((numGlyphs + 31) / 32) */ /* Size of bboxBitmap = 4 * floor((numGlyphs + 31) / 32) */
bitmap_length = ( ( num_glyphs + 31U ) >> 5 ) << 2; bbox_bitmap_length = ( ( num_glyphs + 31U ) >> 5 ) << 2;
substreams[BBOX_STREAM].offset += bitmap_length; /* bboxStreamSize is the combined size of bboxBitmap and bboxStream. */
substreams[BBOX_STREAM].offset += bbox_bitmap_length;
glyph_buf_size = WOFF2_DEFAULT_GLYPH_BUF; glyph_buf_size = WOFF2_DEFAULT_GLYPH_BUF;
if ( FT_NEW_ARRAY( glyph_buf, glyph_buf_size ) ) if ( FT_NEW_ARRAY( glyph_buf, glyph_buf_size ) )
@ -1025,8 +1051,11 @@
FT_ULong flag_size; FT_ULong flag_size;
FT_ULong triplet_size; FT_ULong triplet_size;
FT_ULong triplet_bytes_used; FT_ULong triplet_bytes_used;
FT_Byte* flags_buf = NULL; FT_Bool have_overlap = FALSE;
FT_Byte* triplet_buf = NULL; FT_Byte overlap_bitmap;
FT_ULong overlap_offset;
FT_Byte* flags_buf = NULL;
FT_Byte* triplet_buf = NULL;
FT_UShort instruction_size; FT_UShort instruction_size;
FT_ULong size_needed; FT_ULong size_needed;
FT_Int end_point; FT_Int end_point;
@ -1035,6 +1064,17 @@
FT_Byte* pointer = NULL; FT_Byte* pointer = NULL;
/* Set `have_overlap`. */
if ( overlap_bitmap_offset )
{
overlap_offset = overlap_bitmap_offset + ( i >> 3 );
if ( FT_STREAM_SEEK( overlap_offset ) ||
FT_READ_BYTE( overlap_bitmap ) )
goto Fail;
if ( overlap_bitmap & ( 0x80 >> ( i & 7 ) ) )
have_overlap = TRUE;
}
if ( FT_NEW_ARRAY( n_points_arr, n_contours ) ) if ( FT_NEW_ARRAY( n_points_arr, n_contours ) )
goto Fail; goto Fail;
@ -1155,6 +1195,7 @@
points, points,
n_contours, n_contours,
instruction_size, instruction_size,
have_overlap,
glyph_buf, glyph_buf,
glyph_buf_size, glyph_buf_size,
&glyph_size ) ) &glyph_size ) )

View File

@ -56,6 +56,7 @@ FT_BEGIN_HEADER
#define GLYF_REPEAT 1 << 3 #define GLYF_REPEAT 1 << 3
#define GLYF_THIS_X_IS_SAME 1 << 4 #define GLYF_THIS_X_IS_SAME 1 << 4
#define GLYF_THIS_Y_IS_SAME 1 << 5 #define GLYF_THIS_Y_IS_SAME 1 << 5
#define GLYF_OVERLAP_SIMPLE 1 << 6
/* Other constants */ /* Other constants */
#define CONTOUR_OFFSET_END_POINT 10 #define CONTOUR_OFFSET_END_POINT 10