diff options
Diffstat (limited to 'src/3rdparty/freetype/src/autofit/afshaper.c')
| -rw-r--r-- | src/3rdparty/freetype/src/autofit/afshaper.c | 683 |
1 files changed, 683 insertions, 0 deletions
diff --git a/src/3rdparty/freetype/src/autofit/afshaper.c b/src/3rdparty/freetype/src/autofit/afshaper.c new file mode 100644 index 0000000000..f30828173c --- /dev/null +++ b/src/3rdparty/freetype/src/autofit/afshaper.c @@ -0,0 +1,683 @@ +/***************************************************************************/ +/* */ +/* afshaper.c */ +/* */ +/* HarfBuzz interface for accessing OpenType features (body). */ +/* */ +/* Copyright 2013-2018 by */ +/* David Turner, Robert Wilhelm, and Werner Lemberg. */ +/* */ +/* This file is part of the FreeType project, and may only be used, */ +/* modified, and distributed under the terms of the FreeType project */ +/* license, LICENSE.TXT. By continuing to use, modify, or distribute */ +/* this file you indicate that you have read the license and */ +/* understand and accept it fully. */ +/* */ +/***************************************************************************/ + + +#include <ft2build.h> +#include FT_FREETYPE_H +#include FT_ADVANCES_H +#include "afglobal.h" +#include "aftypes.h" +#include "afshaper.h" + +#ifdef FT_CONFIG_OPTION_USE_HARFBUZZ + + + /*************************************************************************/ + /* */ + /* The macro FT_COMPONENT is used in trace mode. It is an implicit */ + /* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log */ + /* messages during execution. */ + /* */ +#undef FT_COMPONENT +#define FT_COMPONENT trace_afshaper + + + /* + * We use `sets' (in the HarfBuzz sense, which comes quite near to the + * usual mathematical meaning) to manage both lookups and glyph indices. + * + * 1. For each coverage, collect lookup IDs in a set. Note that an + * auto-hinter `coverage' is represented by one `feature', and a + * feature consists of an arbitrary number of (font specific) `lookup's + * that actually do the mapping job. Please check the OpenType + * specification for more details on features and lookups. + * + * 2. Create glyph ID sets from the corresponding lookup sets. + * + * 3. The glyph set corresponding to AF_COVERAGE_DEFAULT is computed + * with all lookups specific to the OpenType script activated. It + * relies on the order of AF_DEFINE_STYLE_CLASS entries so that + * special coverages (like `oldstyle figures') don't get overwritten. + * + */ + + + /* load coverage tags */ +#undef COVERAGE +#define COVERAGE( name, NAME, description, \ + tag1, tag2, tag3, tag4 ) \ + static const hb_tag_t name ## _coverage[] = \ + { \ + HB_TAG( tag1, tag2, tag3, tag4 ), \ + HB_TAG_NONE \ + }; + + +#include "afcover.h" + + + /* define mapping between coverage tags and AF_Coverage */ +#undef COVERAGE +#define COVERAGE( name, NAME, description, \ + tag1, tag2, tag3, tag4 ) \ + name ## _coverage, + + + static const hb_tag_t* coverages[] = + { +#include "afcover.h" + + NULL /* AF_COVERAGE_DEFAULT */ + }; + + + /* load HarfBuzz script tags */ +#undef SCRIPT +#define SCRIPT( s, S, d, h, H, ss ) h, + + + static const hb_script_t scripts[] = + { +#include "afscript.h" + }; + + + FT_Error + af_shaper_get_coverage( AF_FaceGlobals globals, + AF_StyleClass style_class, + FT_UShort* gstyles, + FT_Bool default_script ) + { + hb_face_t* face; + + hb_set_t* gsub_lookups = NULL; /* GSUB lookups for a given script */ + hb_set_t* gsub_glyphs = NULL; /* glyphs covered by GSUB lookups */ + hb_set_t* gpos_lookups = NULL; /* GPOS lookups for a given script */ + hb_set_t* gpos_glyphs = NULL; /* glyphs covered by GPOS lookups */ + + hb_script_t script; + const hb_tag_t* coverage_tags; + hb_tag_t script_tags[] = { HB_TAG_NONE, + HB_TAG_NONE, + HB_TAG_NONE, + HB_TAG_NONE }; + + hb_codepoint_t idx; +#ifdef FT_DEBUG_LEVEL_TRACE + int count; +#endif + + + if ( !globals || !style_class || !gstyles ) + return FT_THROW( Invalid_Argument ); + + face = hb_font_get_face( globals->hb_font ); + + coverage_tags = coverages[style_class->coverage]; + script = scripts[style_class->script]; + + /* Convert a HarfBuzz script tag into the corresponding OpenType */ + /* tag or tags -- some Indic scripts like Devanagari have an old */ + /* and a new set of features. */ + hb_ot_tags_from_script( script, + &script_tags[0], + &script_tags[1] ); + + /* `hb_ot_tags_from_script' usually returns HB_OT_TAG_DEFAULT_SCRIPT */ + /* as the second tag. We change that to HB_TAG_NONE except for the */ + /* default script. */ + if ( default_script ) + { + if ( script_tags[0] == HB_TAG_NONE ) + script_tags[0] = HB_OT_TAG_DEFAULT_SCRIPT; + else + { + if ( script_tags[1] == HB_TAG_NONE ) + script_tags[1] = HB_OT_TAG_DEFAULT_SCRIPT; + else if ( script_tags[1] != HB_OT_TAG_DEFAULT_SCRIPT ) + script_tags[2] = HB_OT_TAG_DEFAULT_SCRIPT; + } + } + else + { + /* we use non-standard tags like `khms' for special purposes; */ + /* HarfBuzz maps them to `DFLT', which we don't want to handle here */ + if ( script_tags[0] == HB_OT_TAG_DEFAULT_SCRIPT ) + goto Exit; + + if ( script_tags[1] == HB_OT_TAG_DEFAULT_SCRIPT ) + script_tags[1] = HB_TAG_NONE; + } + + gsub_lookups = hb_set_create(); + hb_ot_layout_collect_lookups( face, + HB_OT_TAG_GSUB, + script_tags, + NULL, + coverage_tags, + gsub_lookups ); + + if ( hb_set_is_empty( gsub_lookups ) ) + goto Exit; /* nothing to do */ + + FT_TRACE4(( "GSUB lookups (style `%s'):\n" + " ", + af_style_names[style_class->style] )); + +#ifdef FT_DEBUG_LEVEL_TRACE + count = 0; +#endif + + gsub_glyphs = hb_set_create(); + for ( idx = HB_SET_VALUE_INVALID; hb_set_next( gsub_lookups, &idx ); ) + { +#ifdef FT_DEBUG_LEVEL_TRACE + FT_TRACE4(( " %d", idx )); + count++; +#endif + + /* get output coverage of GSUB feature */ + hb_ot_layout_lookup_collect_glyphs( face, + HB_OT_TAG_GSUB, + idx, + NULL, + NULL, + NULL, + gsub_glyphs ); + } + +#ifdef FT_DEBUG_LEVEL_TRACE + if ( !count ) + FT_TRACE4(( " (none)" )); + FT_TRACE4(( "\n\n" )); +#endif + + FT_TRACE4(( "GPOS lookups (style `%s'):\n" + " ", + af_style_names[style_class->style] )); + + gpos_lookups = hb_set_create(); + hb_ot_layout_collect_lookups( face, + HB_OT_TAG_GPOS, + script_tags, + NULL, + coverage_tags, + gpos_lookups ); + +#ifdef FT_DEBUG_LEVEL_TRACE + count = 0; +#endif + + gpos_glyphs = hb_set_create(); + for ( idx = HB_SET_VALUE_INVALID; hb_set_next( gpos_lookups, &idx ); ) + { +#ifdef FT_DEBUG_LEVEL_TRACE + FT_TRACE4(( " %d", idx )); + count++; +#endif + + /* get input coverage of GPOS feature */ + hb_ot_layout_lookup_collect_glyphs( face, + HB_OT_TAG_GPOS, + idx, + NULL, + gpos_glyphs, + NULL, + NULL ); + } + +#ifdef FT_DEBUG_LEVEL_TRACE + if ( !count ) + FT_TRACE4(( " (none)" )); + FT_TRACE4(( "\n\n" )); +#endif + + /* + * We now check whether we can construct blue zones, using glyphs + * covered by the feature only. In case there is not a single zone + * (this is, not a single character is covered), we skip this coverage. + * + */ + if ( style_class->coverage != AF_COVERAGE_DEFAULT ) + { + AF_Blue_Stringset bss = style_class->blue_stringset; + const AF_Blue_StringRec* bs = &af_blue_stringsets[bss]; + + FT_Bool found = 0; + + + for ( ; bs->string != AF_BLUE_STRING_MAX; bs++ ) + { + const char* p = &af_blue_strings[bs->string]; + + + while ( *p ) + { + hb_codepoint_t ch; + + + GET_UTF8_CHAR( ch, p ); + + for ( idx = HB_SET_VALUE_INVALID; hb_set_next( gsub_lookups, + &idx ); ) + { + hb_codepoint_t gidx = FT_Get_Char_Index( globals->face, ch ); + + + if ( hb_ot_layout_lookup_would_substitute( face, idx, + &gidx, 1, 1 ) ) + { + found = 1; + break; + } + } + } + } + + if ( !found ) + { + FT_TRACE4(( " no blue characters found; style skipped\n" )); + goto Exit; + } + } + + /* + * Various OpenType features might use the same glyphs at different + * vertical positions; for example, superscript and subscript glyphs + * could be the same. However, the auto-hinter is completely + * agnostic of OpenType features after the feature analysis has been + * completed: The engine then simply receives a glyph index and returns a + * hinted and usually rendered glyph. + * + * Consider the superscript feature of font `pala.ttf': Some of the + * glyphs are `real', this is, they have a zero vertical offset, but + * most of them are small caps glyphs shifted up to the superscript + * position (this is, the `sups' feature is present in both the GSUB and + * GPOS tables). The code for blue zones computation actually uses a + * feature's y offset so that the `real' glyphs get correct hints. But + * later on it is impossible to decide whether a glyph index belongs to, + * say, the small caps or superscript feature. + * + * For this reason, we don't assign a style to a glyph if the current + * feature covers the glyph in both the GSUB and the GPOS tables. This + * is quite a broad condition, assuming that + * + * (a) glyphs that get used in multiple features are present in a + * feature without vertical shift, + * + * and + * + * (b) a feature's GPOS data really moves the glyph vertically. + * + * Not fulfilling condition (a) makes a font larger; it would also + * reduce the number of glyphs that could be addressed directly without + * using OpenType features, so this assumption is rather strong. + * + * Condition (b) is much weaker, and there might be glyphs which get + * missed. However, the OpenType features we are going to handle are + * primarily located in GSUB, and HarfBuzz doesn't provide an API to + * directly get the necessary information from the GPOS table. A + * possible solution might be to directly parse the GPOS table to find + * out whether a glyph gets shifted vertically, but this is something I + * would like to avoid if not really necessary. + * + * Note that we don't follow this logic for the default coverage. + * Complex scripts like Devanagari have mandatory GPOS features to + * position many glyph elements, using mark-to-base or mark-to-ligature + * tables; the number of glyphs missed due to condition (b) would be far + * too large. + * + */ + if ( style_class->coverage != AF_COVERAGE_DEFAULT ) + hb_set_subtract( gsub_glyphs, gpos_glyphs ); + +#ifdef FT_DEBUG_LEVEL_TRACE + FT_TRACE4(( " glyphs without GPOS data (`*' means already assigned)" )); + count = 0; +#endif + + for ( idx = HB_SET_VALUE_INVALID; hb_set_next( gsub_glyphs, &idx ); ) + { +#ifdef FT_DEBUG_LEVEL_TRACE + if ( !( count % 10 ) ) + FT_TRACE4(( "\n" + " " )); + + FT_TRACE4(( " %d", idx )); + count++; +#endif + + /* glyph indices returned by `hb_ot_layout_lookup_collect_glyphs' */ + /* can be arbitrary: some fonts use fake indices for processing */ + /* internal to GSUB or GPOS, which is fully valid */ + if ( idx >= (hb_codepoint_t)globals->glyph_count ) + continue; + + if ( gstyles[idx] == AF_STYLE_UNASSIGNED ) + gstyles[idx] = (FT_UShort)style_class->style; +#ifdef FT_DEBUG_LEVEL_TRACE + else + FT_TRACE4(( "*" )); +#endif + } + +#ifdef FT_DEBUG_LEVEL_TRACE + if ( !count ) + FT_TRACE4(( "\n" + " (none)" )); + FT_TRACE4(( "\n\n" )); +#endif + + Exit: + hb_set_destroy( gsub_lookups ); + hb_set_destroy( gsub_glyphs ); + hb_set_destroy( gpos_lookups ); + hb_set_destroy( gpos_glyphs ); + + return FT_Err_Ok; + } + + + /* construct HarfBuzz features */ +#undef COVERAGE +#define COVERAGE( name, NAME, description, \ + tag1, tag2, tag3, tag4 ) \ + static const hb_feature_t name ## _feature[] = \ + { \ + { \ + HB_TAG( tag1, tag2, tag3, tag4 ), \ + 1, 0, (unsigned int)-1 \ + } \ + }; + + +#include "afcover.h" + + + /* define mapping between HarfBuzz features and AF_Coverage */ +#undef COVERAGE +#define COVERAGE( name, NAME, description, \ + tag1, tag2, tag3, tag4 ) \ + name ## _feature, + + + static const hb_feature_t* features[] = + { +#include "afcover.h" + + NULL /* AF_COVERAGE_DEFAULT */ + }; + + + void* + af_shaper_buf_create( FT_Face face ) + { + FT_UNUSED( face ); + + return (void*)hb_buffer_create(); + } + + + void + af_shaper_buf_destroy( FT_Face face, + void* buf ) + { + FT_UNUSED( face ); + + hb_buffer_destroy( (hb_buffer_t*)buf ); + } + + + const char* + af_shaper_get_cluster( const char* p, + AF_StyleMetrics metrics, + void* buf_, + unsigned int* count ) + { + AF_StyleClass style_class; + const hb_feature_t* feature; + FT_Int upem; + const char* q; + int len; + + hb_buffer_t* buf = (hb_buffer_t*)buf_; + hb_font_t* font; + hb_codepoint_t dummy; + + + upem = (FT_Int)metrics->globals->face->units_per_EM; + style_class = metrics->style_class; + feature = features[style_class->coverage]; + + font = metrics->globals->hb_font; + + /* we shape at a size of units per EM; this means font units */ + hb_font_set_scale( font, upem, upem ); + + while ( *p == ' ' ) + p++; + + /* count bytes up to next space (or end of buffer) */ + q = p; + while ( !( *q == ' ' || *q == '\0' ) ) + GET_UTF8_CHAR( dummy, q ); + len = (int)( q - p ); + + /* feed character(s) to the HarfBuzz buffer */ + hb_buffer_clear_contents( buf ); + hb_buffer_add_utf8( buf, p, len, 0, len ); + + /* we let HarfBuzz guess the script and writing direction */ + hb_buffer_guess_segment_properties( buf ); + + /* shape buffer, which means conversion from character codes to */ + /* glyph indices, possibly applying a feature */ + hb_shape( font, buf, feature, feature ? 1 : 0 ); + + if ( feature ) + { + hb_buffer_t* hb_buf = metrics->globals->hb_buf; + + unsigned int gcount; + hb_glyph_info_t* ginfo; + + unsigned int hb_gcount; + hb_glyph_info_t* hb_ginfo; + + + /* we have to check whether applying a feature does actually change */ + /* glyph indices; otherwise the affected glyph or glyphs aren't */ + /* available at all in the feature */ + + hb_buffer_clear_contents( hb_buf ); + hb_buffer_add_utf8( hb_buf, p, len, 0, len ); + hb_buffer_guess_segment_properties( hb_buf ); + hb_shape( font, hb_buf, NULL, 0 ); + + ginfo = hb_buffer_get_glyph_infos( buf, &gcount ); + hb_ginfo = hb_buffer_get_glyph_infos( hb_buf, &hb_gcount ); + + if ( gcount == hb_gcount ) + { + unsigned int i; + + + for (i = 0; i < gcount; i++ ) + if ( ginfo[i].codepoint != hb_ginfo[i].codepoint ) + break; + + if ( i == gcount ) + { + /* both buffers have identical glyph indices */ + hb_buffer_clear_contents( buf ); + } + } + } + + *count = hb_buffer_get_length( buf ); + +#ifdef FT_DEBUG_LEVEL_TRACE + if ( feature && *count > 1 ) + FT_TRACE1(( "af_shaper_get_cluster:" + " input character mapped to multiple glyphs\n" )); +#endif + + return q; + } + + + FT_ULong + af_shaper_get_elem( AF_StyleMetrics metrics, + void* buf_, + unsigned int idx, + FT_Long* advance, + FT_Long* y_offset ) + { + hb_buffer_t* buf = (hb_buffer_t*)buf_; + hb_glyph_info_t* ginfo; + hb_glyph_position_t* gpos; + unsigned int gcount; + + FT_UNUSED( metrics ); + + + ginfo = hb_buffer_get_glyph_infos( buf, &gcount ); + gpos = hb_buffer_get_glyph_positions( buf, &gcount ); + + if ( idx >= gcount ) + return 0; + + if ( advance ) + *advance = gpos[idx].x_advance; + if ( y_offset ) + *y_offset = gpos[idx].y_offset; + + return ginfo[idx].codepoint; + } + + +#else /* !FT_CONFIG_OPTION_USE_HARFBUZZ */ + + + FT_Error + af_shaper_get_coverage( AF_FaceGlobals globals, + AF_StyleClass style_class, + FT_UShort* gstyles, + FT_Bool default_script ) + { + FT_UNUSED( globals ); + FT_UNUSED( style_class ); + FT_UNUSED( gstyles ); + FT_UNUSED( default_script ); + + return FT_Err_Ok; + } + + + void* + af_shaper_buf_create( FT_Face face ) + { + FT_Error error; + FT_Memory memory = face->memory; + FT_ULong* buf; + + + FT_MEM_ALLOC( buf, sizeof ( FT_ULong ) ); + + return (void*)buf; + } + + + void + af_shaper_buf_destroy( FT_Face face, + void* buf ) + { + FT_Memory memory = face->memory; + + + FT_FREE( buf ); + } + + + const char* + af_shaper_get_cluster( const char* p, + AF_StyleMetrics metrics, + void* buf_, + unsigned int* count ) + { + FT_Face face = metrics->globals->face; + FT_ULong ch, dummy = 0; + FT_ULong* buf = (FT_ULong*)buf_; + + + while ( *p == ' ' ) + p++; + + GET_UTF8_CHAR( ch, p ); + + /* since we don't have an engine to handle clusters, */ + /* we scan the characters but return zero */ + while ( !( *p == ' ' || *p == '\0' ) ) + GET_UTF8_CHAR( dummy, p ); + + if ( dummy ) + { + *buf = 0; + *count = 0; + } + else + { + *buf = FT_Get_Char_Index( face, ch ); + *count = 1; + } + + return p; + } + + + FT_ULong + af_shaper_get_elem( AF_StyleMetrics metrics, + void* buf_, + unsigned int idx, + FT_Long* advance, + FT_Long* y_offset ) + { + FT_Face face = metrics->globals->face; + FT_ULong glyph_index = *(FT_ULong*)buf_; + + FT_UNUSED( idx ); + + + if ( advance ) + FT_Get_Advance( face, + glyph_index, + FT_LOAD_NO_SCALE | + FT_LOAD_NO_HINTING | + FT_LOAD_IGNORE_TRANSFORM, + advance ); + + if ( y_offset ) + *y_offset = 0; + + return glyph_index; + } + + +#endif /* !FT_CONFIG_OPTION_USE_HARFBUZZ */ + + +/* END */ |