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Wrap up all glyph variant algorithm

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This commit is contained in:
Craig White 2023-09-26 22:43:47 -04:00
parent 2c473abb1c
commit e0f9830b00
1 changed files with 46 additions and 31 deletions
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77
src/autofit/afadjust.c
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@ -223,7 +223,7 @@ af_reverse_character_map_lookup_( AF_ReverseCharacterMap map, FT_Int glyph_index
}
/* Binary search for reverse character map entry */
FT_Int low = 0;
FT_Int high = map->length - 1;
FT_Int high = length - 1;
while ( high >= low )
{
FT_Int mid = ( high + low ) / 2;
@ -283,6 +283,13 @@ af_reverse_character_map_entry_compare( const void *a, const void *b ) {
}
#ifdef FT_CONFIG_OPTION_USE_HARFBUZZ
/*Recursive algorithm to find all glyphs that a codepoint could turn into from the GSUB table.
buffer: a buffer containing only the input codepoint
feature_tag_pool: the current list of features under consideration
current_features: the current list of features being applied
num_features: length of current_features
result: the set of glyphs in the answer
*/
FT_LOCAL_DEF( FT_Error )
af_all_glyph_variants_helper( hb_font_t *font,
hb_buffer_t *buffer,
@ -291,6 +298,8 @@ af_all_glyph_variants_helper( hb_font_t *font,
FT_UInt32 num_features,
hb_set_t* result )
{
/*get the list of glyphs that are created by only transforming based on the
features in current features*/
hb_set_t *baseline_glyphs = hb_set_create();
if ( !hb_set_allocation_successful( baseline_glyphs ) )
{
@ -302,7 +311,13 @@ af_all_glyph_variants_helper( hb_font_t *font,
current_features,
num_features,
baseline_glyphs );
if ( !hb_set_allocation_successful( baseline_glyphs ) )
{
return FT_Err_Out_Of_Memory;
}
/*Add these baseline glyphs to the results. The baseline glyphs
will contain at minimum the glyph specified by CMAP*/
hb_set_union( result, baseline_glyphs );
if ( !hb_set_allocation_successful( result ) )
{
@ -313,26 +328,27 @@ af_all_glyph_variants_helper( hb_font_t *font,
return FT_Err_Ok;
}
/*set the feature to apply to the entire input buffer*/
/*setup to try adding different features to current_features
to see if any of them have an effect of the glyphs we get from
hb_ot_shape_glyphs_closure*/
current_features[num_features].start = HB_FEATURE_GLOBAL_START;
current_features[num_features].end = HB_FEATURE_GLOBAL_END;
current_features[num_features].value = 1; /*set the feature to enabled*/
/*quote from docs about value attribute:
0 disables the feature, non-zero (usually 1) enables the feature. For features implemented as lookup type 3 (like 'salt') the value is a one based index into the alternates.
this does not handle these lookup type 3 cases fully*/
this algorithm does not handle these lookup type 3 cases fully*/
/*feature tag will be determined by trying all feature tags, looking for anything that affects the result of the lookup*/
hb_set_t *new_glyphs = hb_set_create();
if ( !hb_set_allocation_successful( new_glyphs ) )
{
return FT_Err_Out_Of_Memory;
}
hb_tag_t feature_tag = HB_SET_VALUE_INVALID;
while ( hb_set_next( feature_tag_pool, &feature_tag ) )
{
hb_set_clear( new_glyphs );
current_features[num_features].tag = feature_tag;
FT_TRACE4(("P3. num: %d\n", num_features));
hb_ot_shape_glyphs_closure ( font,
buffer,
current_features,
@ -343,12 +359,13 @@ af_all_glyph_variants_helper( hb_font_t *font,
return FT_Err_Out_Of_Memory;
}
hb_set_subtract( new_glyphs, baseline_glyphs );
/*glyphs now contains all glyphs that were added to the*/
/*closure as a result of adding this feature*/
/*If this is not a subset of result, this feature is relevant*/
/*and we should recurse*/
if ( !hb_set_is_subset( new_glyphs, result ) )
hb_set_subtract( new_glyphs, result );
/*new_glyphs now contains all glyphs that appeared in the result
of hb_ot_shape_glyphs_closure that haven't already been accounted for in the result.
If this contains any glyphs, we also need to try this feature
in combination will other features by recursing
*/
if ( hb_set_get_population( new_glyphs ) != 0 )
{
/*remove this feature from the feature pool so that
the later recursion won't try it*/
@ -386,12 +403,15 @@ af_all_glyph_variants( FT_Face face,
FT_Memory memory = face->memory;
FT_Error error;
hb_face_t *hb_face = hb_font_get_face( hb_font );
/*The set of all feature tags in the font*/
hb_set_t *feature_tags = hb_set_create();
if ( !hb_set_allocation_successful( feature_tags ) )
{
return FT_Err_Out_Of_Memory;
}
/*populate feature_tags using the output of hb_ot_layout_table_get_feature_tags*/
FT_Bool feature_list_done = 0;
unsigned int start_offset = 0;
while ( !feature_list_done ) {
@ -417,6 +437,7 @@ af_all_glyph_variants( FT_Face face,
}
}
/*make a buffer only consisting of the given codepoint*/
hb_buffer_t *codepoint_buffer = hb_buffer_create();
if ( !hb_buffer_allocation_successful( codepoint_buffer ) )
{
@ -430,12 +451,15 @@ af_all_glyph_variants( FT_Face face,
HB_DIRECTION_LTR);
hb_buffer_add( codepoint_buffer, codepoint, 0 );
/*The array of features that will be used by the recursive part
it will have at most as many entries as there are features, so
make the length = length of feature_tags*/
hb_feature_t *feature_buffer;
if ( FT_NEW_ARRAY( feature_buffer, hb_set_get_population( feature_tags ) ) ) {
if ( FT_NEW_ARRAY( feature_buffer, hb_set_get_population( feature_tags ) ) )
{
return error;
}
/*hb_codepoint_t and hb_tag_t are both uint32_t, so we can put feature tags inside hb_set*/
error = af_all_glyph_variants_helper( hb_font,
codepoint_buffer,
feature_tags,
@ -446,7 +470,7 @@ af_all_glyph_variants( FT_Face face,
hb_set_destroy( feature_tags );
hb_buffer_destroy( codepoint_buffer );
FT_FREE( feature_buffer );
return FT_Err_Ok;
return error;
}
#endif /*FT_CONFIG_OPTION_USE_HARFBUZZ*/
@ -492,21 +516,18 @@ af_reverse_character_map_new( AF_ReverseCharacterMap *map, AF_FaceGlobals global
goto harfbuzz_path_Exit;
}
/*
af_all_glyph_variants( FT_Face face,
hb_font_t *hb_font,
FT_UInt32 codepoint,
hb_set_t* result )*/
/*find alll glyph variants of the codepoints, then make an entry from
the glyph to the codepoint for each one*/
for ( FT_Long i = 0; i < AF_ADJUSTMENT_DATABASE_LENGTH; i++ )
{
FT_UInt32 codepoint = adjustment_database[i].codepoint;
error = af_all_glyph_variants( face,
hb_font,
codepoint,
result_set );
if ( error ) {
if ( error )
{
goto harfbuzz_path_Exit;
}
@ -518,14 +539,13 @@ af_reverse_character_map_new( AF_ReverseCharacterMap *map, AF_FaceGlobals global
goto harfbuzz_path_Exit;
}
FT_Long insert_point = ( *map )->length;
( *map )->length++;
( *map )->entries[i].glyph_index = glyph;
( *map )->entries[i].codepoint = codepoint;
( *map )->entries[insert_point].glyph_index = glyph;
( *map )->entries[insert_point].codepoint = codepoint;
}
hb_set_clear( result_set );
}
harfbuzz_path_Exit:
hb_set_destroy( result_set );
@ -567,11 +587,6 @@ harfbuzz_path_Exit:
af_reverse_character_map_entry_compare
);
for ( FT_Long i = 0; i < ( *map )->length; i++ )
{
FT_TRACE4(("char: %c, glyph: %d\n", ( *map )->entries[i].codepoint, ( *map )->entries[i].glyph_index ) );
}
FT_TRACE4(( " reverse character map built successfully"\
" with %d entries\n", (*map)->length ));