[Git][freetype/freetype][gsoc-craig-2023] Wrap up all glyph variant algorithm

[Craig White (@gerzytet)]

Craig White pushed to branch gsoc-craig-2023 at FreeType / FreeType

Commits:

• e0f9830b
  by Craig White at 2023-09-26T22:43:47-04:00

  Wrap up all glyph variant algorithm
  

1 changed file:

• src/autofit/afadjust.c

Changes:

src/autofit/afadjust.c

---

...	...	@@ -223,7 +223,7 @@ af_reverse_character_map_lookup_( AF_ReverseCharacterMap map, FT_Int glyph_index
223	223	}
224	224	/* Binary search for reverse character map entry */
225	225	FT_Int low = 0;
226		- FT_Int high = map->length - 1;
	226	+ FT_Int high = length - 1;
227	227	while ( high >= low )
228	228	{
229	229	FT_Int mid = ( high + low ) / 2;
...	...	@@ -283,6 +283,13 @@ af_reverse_character_map_entry_compare( const void *a, const void *b ) {
283	283	}
284	284
285	285	#ifdef FT_CONFIG_OPTION_USE_HARFBUZZ
	286	+/*Recursive algorithm to find all glyphs that a codepoint could turn into from the GSUB table.
	287	+buffer: a buffer containing only the input codepoint
	288	+feature_tag_pool: the current list of features under consideration
	289	+current_features: the current list of features being applied
	290	+num_features: length of current_features
	291	+result: the set of glyphs in the answer
	292	+*/
286	293	FT_LOCAL_DEF( FT_Error )
287	294	af_all_glyph_variants_helper( hb_font_t *font,
288	295	hb_buffer_t *buffer,
...	...	@@ -291,6 +298,8 @@ af_all_glyph_variants_helper( hb_font_t *font,
291	298	FT_UInt32 num_features,
292	299	hb_set_t* result )
293	300	{
	301	+ /*get the list of glyphs that are created by only transforming based on the
	302	+ features in current features*/
294	303	hb_set_t *baseline_glyphs = hb_set_create();
295	304	if ( !hb_set_allocation_successful( baseline_glyphs ) )
296	305	{
...	...	@@ -302,7 +311,13 @@ af_all_glyph_variants_helper( hb_font_t *font,
302	311	current_features,
303	312	num_features,
304	313	baseline_glyphs );
	314	+ if ( !hb_set_allocation_successful( baseline_glyphs ) )
	315	+ {
	316	+ return FT_Err_Out_Of_Memory;
	317	+ }
305	318
	319	+ /*Add these baseline glyphs to the results. The baseline glyphs
	320	+ will contain at minimum the glyph specified by CMAP*/
306	321	hb_set_union( result, baseline_glyphs );
307	322	if ( !hb_set_allocation_successful( result ) )
308	323	{
...	...	@@ -313,26 +328,27 @@ af_all_glyph_variants_helper( hb_font_t *font,
313	328	return FT_Err_Ok;
314	329	}
315	330
316		- /*set the feature to apply to the entire input buffer*/
	331	+ /*setup to try adding different features to current_features
	332	+ to see if any of them have an effect of the glyphs we get from
	333	+ hb_ot_shape_glyphs_closure*/
317	334	current_features[num_features].start = HB_FEATURE_GLOBAL_START;
318	335	current_features[num_features].end = HB_FEATURE_GLOBAL_END;
319	336	current_features[num_features].value = 1; /*set the feature to enabled*/
320	337	/*quote from docs about value attribute:
321	338	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.
322		- this does not handle these lookup type 3 cases fully*/
	339	+ this algorithm does not handle these lookup type 3 cases fully*/
323	340
324		- /*feature tag will be determined by trying all feature tags, looking for anything that affects the result of the lookup*/
325	341	hb_set_t *new_glyphs = hb_set_create();
326	342	if ( !hb_set_allocation_successful( new_glyphs ) )
327	343	{
328	344	return FT_Err_Out_Of_Memory;
329	345	}
	346	+
330	347	hb_tag_t feature_tag = HB_SET_VALUE_INVALID;
331	348	while ( hb_set_next( feature_tag_pool, &feature_tag ) )
332	349	{
333	350	hb_set_clear( new_glyphs );
334	351	current_features[num_features].tag = feature_tag;
335		- FT_TRACE4(("P3. num: %d\n", num_features));
336	352	hb_ot_shape_glyphs_closure ( font,
337	353	buffer,
338	354	current_features,
...	...	@@ -343,12 +359,13 @@ af_all_glyph_variants_helper( hb_font_t *font,
343	359	return FT_Err_Out_Of_Memory;
344	360	}
345	361
346		- hb_set_subtract( new_glyphs, baseline_glyphs );
347		- /*glyphs now contains all glyphs that were added to the*/
348		- /*closure as a result of adding this feature*/
349		- /*If this is not a subset of result, this feature is relevant*/
350		- /*and we should recurse*/
351		- if ( !hb_set_is_subset( new_glyphs, result ) )
	362	+ hb_set_subtract( new_glyphs, result );
	363	+ /*new_glyphs now contains all glyphs that appeared in the result
	364	+ of hb_ot_shape_glyphs_closure that haven't already been accounted for in the result.
	365	+ If this contains any glyphs, we also need to try this feature
	366	+ in combination will other features by recursing
	367	+ */
	368	+ if ( hb_set_get_population( new_glyphs ) != 0 )
352	369	{
353	370	/*remove this feature from the feature pool so that
354	371	the later recursion won't try it*/
...	...	@@ -386,12 +403,15 @@ af_all_glyph_variants( FT_Face face,
386	403	FT_Memory memory = face->memory;
387	404	FT_Error error;
388	405	hb_face_t *hb_face = hb_font_get_face( hb_font );
	406	+
	407	+ /*The set of all feature tags in the font*/
389	408	hb_set_t *feature_tags = hb_set_create();
390	409	if ( !hb_set_allocation_successful( feature_tags ) )
391	410	{
392	411	return FT_Err_Out_Of_Memory;
393	412	}
394	413
	414	+ /*populate feature_tags using the output of hb_ot_layout_table_get_feature_tags*/
395	415	FT_Bool feature_list_done = 0;
396	416	unsigned int start_offset = 0;
397	417	while ( !feature_list_done ) {
...	...	@@ -417,6 +437,7 @@ af_all_glyph_variants( FT_Face face,
417	437	}
418	438	}
419	439
	440	+ /*make a buffer only consisting of the given codepoint*/
420	441	hb_buffer_t *codepoint_buffer = hb_buffer_create();
421	442	if ( !hb_buffer_allocation_successful( codepoint_buffer ) )
422	443	{
...	...	@@ -430,12 +451,15 @@ af_all_glyph_variants( FT_Face face,
430	451	HB_DIRECTION_LTR);
431	452	hb_buffer_add( codepoint_buffer, codepoint, 0 );
432	453
	454	+ /*The array of features that will be used by the recursive part
	455	+ it will have at most as many entries as there are features, so
	456	+ make the length = length of feature_tags*/
433	457	hb_feature_t *feature_buffer;
434		- if ( FT_NEW_ARRAY( feature_buffer, hb_set_get_population( feature_tags ) ) ) {
	458	+ if ( FT_NEW_ARRAY( feature_buffer, hb_set_get_population( feature_tags ) ) )
	459	+ {
435	460	return error;
436	461	}
437	462
438		- /*hb_codepoint_t and hb_tag_t are both uint32_t, so we can put feature tags inside hb_set*/
439	463	error = af_all_glyph_variants_helper( hb_font,
440	464	codepoint_buffer,
441	465	feature_tags,
...	...	@@ -446,7 +470,7 @@ af_all_glyph_variants( FT_Face face,
446	470	hb_set_destroy( feature_tags );
447	471	hb_buffer_destroy( codepoint_buffer );
448	472	FT_FREE( feature_buffer );
449		- return FT_Err_Ok;
	473	+ return error;
450	474	}
451	475	#endif /*FT_CONFIG_OPTION_USE_HARFBUZZ*/
452	476
...	...	@@ -492,21 +516,18 @@ af_reverse_character_map_new( AF_ReverseCharacterMap *map, AF_FaceGlobals global
492	516	goto harfbuzz_path_Exit;
493	517	}
494	518
495		-
496		- /*
497		- af_all_glyph_variants( FT_Face face,
498		- hb_font_t *hb_font,
499		- FT_UInt32 codepoint,
500		- hb_set_t* result )*/
501		-
	519	+ /*find alll glyph variants of the codepoints, then make an entry from
	520	+ the glyph to the codepoint for each one*/
502	521	for ( FT_Long i = 0; i < AF_ADJUSTMENT_DATABASE_LENGTH; i++ )
503	522	{
504	523	FT_UInt32 codepoint = adjustment_database[i].codepoint;
	524	+
505	525	error = af_all_glyph_variants( face,
506	526	hb_font,
507	527	codepoint,
508	528	result_set );
509		- if ( error ) {
	529	+ if ( error )
	530	+ {
510	531	goto harfbuzz_path_Exit;
511	532	}
512	533
...	...	@@ -518,14 +539,13 @@ af_reverse_character_map_new( AF_ReverseCharacterMap *map, AF_FaceGlobals global
518	539	goto harfbuzz_path_Exit;
519	540	}
520	541
	542	+ FT_Long insert_point = ( *map )->length;
521	543	( *map )->length++;
522		- ( *map )->entries[i].glyph_index = glyph;
523		- ( *map )->entries[i].codepoint = codepoint;
524		-
	544	+ ( *map )->entries[insert_point].glyph_index = glyph;
	545	+ ( *map )->entries[insert_point].codepoint = codepoint;
525	546	}
526	547
527	548	hb_set_clear( result_set );
528		-
529	549	}
530	550	harfbuzz_path_Exit:
531	551	hb_set_destroy( result_set );
...	...	@@ -567,11 +587,6 @@ harfbuzz_path_Exit:
567	587	af_reverse_character_map_entry_compare
568	588	);
569	589
570		- for ( FT_Long i = 0; i < ( *map )->length; i++ )
571		- {
572		- FT_TRACE4(("char: %c, glyph: %d\n", ( *map )->entries[i].codepoint, ( *map )->entries[i].glyph_index ) );
573		- }
574		-
575	590	FT_TRACE4(( " reverse character map built successfully"\
576	591	" with %d entries\n", (*map)->length ));
577	592

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