Edit
kc3-lang/freetype/src/autofit/aflatin.c
luz paz
- src/autofit/aflatin.c
-
/**************************************************************************** * * aflatin.c * * Auto-fitter hinting routines for latin writing system (body). * * Copyright (C) 2003-2024 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 <freetype/ftadvanc.h> #include <freetype/internal/ftdebug.h> #include "afglobal.h" #include "aflatin.h" #include "aferrors.h" /************************************************************************** * * 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 aflatin /* needed for computation of round vs. flat segments */ #define FLAT_THRESHOLD( x ) ( x / 14 ) /*************************************************************************/ /*************************************************************************/ /***** *****/ /***** L A T I N G L O B A L M E T R I C S *****/ /***** *****/ /*************************************************************************/ /*************************************************************************/ /* Find segments and links, compute all stem widths, and initialize */ /* standard width and height for the glyph with given charcode. */ FT_LOCAL_DEF( void ) af_latin_metrics_init_widths( AF_LatinMetrics metrics, FT_Face face ) { /* scan the array of segments in each direction */ AF_GlyphHintsRec hints[1]; FT_TRACE5(( "\n" )); FT_TRACE5(( "latin standard widths computation (style `%s')\n", af_style_names[metrics->root.style_class->style] )); FT_TRACE5(( "=====================================================\n" )); FT_TRACE5(( "\n" )); af_glyph_hints_init( hints, face->memory ); metrics->axis[AF_DIMENSION_HORZ].width_count = 0; metrics->axis[AF_DIMENSION_VERT].width_count = 0; { FT_Error error; FT_ULong glyph_index; int dim; AF_LatinMetricsRec dummy[1]; AF_Scaler scaler = &dummy->root.scaler; AF_StyleClass style_class = metrics->root.style_class; AF_ScriptClass script_class = af_script_classes[style_class->script]; /* If HarfBuzz is not available, we need a pointer to a single */ /* unsigned long value. */ #ifdef FT_CONFIG_OPTION_USE_HARFBUZZ void* shaper_buf; #else FT_ULong shaper_buf_; void* shaper_buf = &shaper_buf_; #endif const char* p; #ifdef FT_DEBUG_LEVEL_TRACE FT_ULong ch = 0; #endif p = script_class->standard_charstring; #ifdef FT_CONFIG_OPTION_USE_HARFBUZZ shaper_buf = af_shaper_buf_create( face ); #endif /* * We check a list of standard characters to catch features like * `c2sc' (small caps from caps) that don't contain lowercase letters * by definition, or other features that mainly operate on numerals. * The first match wins. */ glyph_index = 0; while ( *p ) { unsigned int num_idx; #ifdef FT_DEBUG_LEVEL_TRACE const char* p_old; #endif while ( *p == ' ' ) p++; #ifdef FT_DEBUG_LEVEL_TRACE p_old = p; GET_UTF8_CHAR( ch, p_old ); #endif /* reject input that maps to more than a single glyph */ p = af_shaper_get_cluster( p, &metrics->root, shaper_buf, &num_idx ); if ( num_idx > 1 ) continue; /* otherwise exit loop if we have a result */ glyph_index = af_shaper_get_elem( &metrics->root, shaper_buf, 0, NULL, NULL ); if ( glyph_index ) break; } af_shaper_buf_destroy( face, shaper_buf ); if ( !glyph_index ) { FT_TRACE5(( "standard character missing;" " using fallback stem widths\n" )); goto Exit; } FT_TRACE5(( "standard character: U+%04lX (glyph index %ld)\n", ch, glyph_index )); error = FT_Load_Glyph( face, glyph_index, FT_LOAD_NO_SCALE ); if ( error || face->glyph->outline.n_points <= 0 ) goto Exit; FT_ZERO( dummy ); dummy->units_per_em = metrics->units_per_em; scaler->x_scale = 0x10000L; scaler->y_scale = 0x10000L; scaler->x_delta = 0; scaler->y_delta = 0; scaler->face = face; scaler->render_mode = FT_RENDER_MODE_NORMAL; scaler->flags = 0; af_glyph_hints_rescale( hints, (AF_StyleMetrics)dummy ); error = af_glyph_hints_reload( hints, &face->glyph->outline ); if ( error ) goto Exit; for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ ) { AF_LatinAxis axis = &metrics->axis[dim]; AF_AxisHints axhints = &hints->axis[dim]; AF_Segment seg, limit, link; FT_UInt num_widths = 0; error = af_latin_hints_compute_segments( hints, (AF_Dimension)dim ); if ( error ) goto Exit; /* * We assume that the glyphs selected for the stem width * computation are `featureless' enough so that the linking * algorithm works fine without adjustments of its scoring * function. */ af_latin_hints_link_segments( hints, 0, NULL, (AF_Dimension)dim ); seg = axhints->segments; limit = FT_OFFSET( seg, axhints->num_segments ); for ( ; seg < limit; seg++ ) { link = seg->link; /* we only consider stem segments there! */ if ( link && link->link == seg && link > seg ) { FT_Pos dist; dist = seg->pos - link->pos; if ( dist < 0 ) dist = -dist; if ( num_widths < AF_LATIN_MAX_WIDTHS ) axis->widths[num_widths++].org = dist; } } /* this also replaces multiple almost identical stem widths */ /* with a single one (the value 100 is heuristic) */ af_sort_and_quantize_widths( &num_widths, axis->widths, dummy->units_per_em / 100 ); axis->width_count = num_widths; } Exit: for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ ) { AF_LatinAxis axis = &metrics->axis[dim]; FT_Pos stdw; stdw = ( axis->width_count > 0 ) ? axis->widths[0].org : AF_LATIN_CONSTANT( metrics, 50 ); /* let's try 20% of the smallest width */ axis->edge_distance_threshold = stdw / 5; axis->standard_width = stdw; axis->extra_light = 0; #ifdef FT_DEBUG_LEVEL_TRACE { FT_UInt i; FT_TRACE5(( "%s widths:\n", dim == AF_DIMENSION_VERT ? "horizontal" : "vertical" )); FT_TRACE5(( " %ld (standard)", axis->standard_width )); for ( i = 1; i < axis->width_count; i++ ) FT_TRACE5(( " %ld", axis->widths[i].org )); FT_TRACE5(( "\n" )); } #endif } } FT_TRACE5(( "\n" )); af_glyph_hints_done( hints ); } static void af_latin_sort_blue( FT_UInt count, AF_LatinBlue* table ) { FT_UInt i, j; AF_LatinBlue swap; /* we sort from bottom to top */ for ( i = 1; i < count; i++ ) { for ( j = i; j > 0; j-- ) { FT_Pos a, b; if ( table[j - 1]->flags & ( AF_LATIN_BLUE_TOP | AF_LATIN_BLUE_SUB_TOP ) ) a = table[j - 1]->ref.org; else a = table[j - 1]->shoot.org; if ( table[j]->flags & ( AF_LATIN_BLUE_TOP | AF_LATIN_BLUE_SUB_TOP ) ) b = table[j]->ref.org; else b = table[j]->shoot.org; if ( b >= a ) break; swap = table[j]; table[j] = table[j - 1]; table[j - 1] = swap; } } } /* Find all blue zones. Flat segments give the reference points, */ /* round segments the overshoot positions. */ static int af_latin_metrics_init_blues( AF_LatinMetrics metrics, FT_Face face ) { FT_Pos flats [AF_BLUE_STRING_MAX_LEN]; FT_Pos rounds[AF_BLUE_STRING_MAX_LEN]; FT_UInt num_flats; FT_UInt num_rounds; AF_LatinBlue blue; FT_Error error; AF_LatinAxis axis = &metrics->axis[AF_DIMENSION_VERT]; FT_Outline outline; AF_StyleClass sc = metrics->root.style_class; AF_Blue_Stringset bss = sc->blue_stringset; const AF_Blue_StringRec* bs = &af_blue_stringsets[bss]; FT_Pos flat_threshold = FLAT_THRESHOLD( metrics->units_per_em ); /* If HarfBuzz is not available, we need a pointer to a single */ /* unsigned long value. */ #ifdef FT_CONFIG_OPTION_USE_HARFBUZZ void* shaper_buf; #else FT_ULong shaper_buf_; void* shaper_buf = &shaper_buf_; #endif /* we walk over the blue character strings as specified in the */ /* style's entry in the `af_blue_stringset' array */ FT_TRACE5(( "latin blue zones computation\n" )); FT_TRACE5(( "============================\n" )); FT_TRACE5(( "\n" )); #ifdef FT_CONFIG_OPTION_USE_HARFBUZZ shaper_buf = af_shaper_buf_create( face ); #endif for ( ; bs->string != AF_BLUE_STRING_MAX; bs++ ) { const char* p = &af_blue_strings[bs->string]; FT_Pos* blue_ref; FT_Pos* blue_shoot; FT_Pos ascender; FT_Pos descender; #ifdef FT_DEBUG_LEVEL_TRACE { FT_Bool have_flag = 0; FT_TRACE5(( "blue zone %d", axis->blue_count )); if ( bs->properties ) { FT_TRACE5(( " (" )); if ( AF_LATIN_IS_TOP_BLUE( bs ) ) { FT_TRACE5(( "top" )); have_flag = 1; } else if ( AF_LATIN_IS_SUB_TOP_BLUE( bs ) ) { FT_TRACE5(( "sub top" )); have_flag = 1; } if ( AF_LATIN_IS_NEUTRAL_BLUE( bs ) ) { if ( have_flag ) FT_TRACE5(( ", " )); FT_TRACE5(( "neutral" )); have_flag = 1; } if ( AF_LATIN_IS_X_HEIGHT_BLUE( bs ) ) { if ( have_flag ) FT_TRACE5(( ", " )); FT_TRACE5(( "small top" )); have_flag = 1; } if ( AF_LATIN_IS_LONG_BLUE( bs ) ) { if ( have_flag ) FT_TRACE5(( ", " )); FT_TRACE5(( "long" )); } FT_TRACE5(( ")" )); } FT_TRACE5(( ":\n" )); } #endif /* FT_DEBUG_LEVEL_TRACE */ num_flats = 0; num_rounds = 0; ascender = 0; descender = 0; while ( *p ) { FT_ULong glyph_index; FT_Long y_offset; FT_Int best_point, best_contour_first, best_contour_last; FT_Vector* points; FT_Pos best_y_extremum; /* same as points.y */ FT_Bool best_round = 0; unsigned int i, num_idx; #ifdef FT_DEBUG_LEVEL_TRACE const char* p_old; FT_ULong ch; #endif while ( *p == ' ' ) p++; #ifdef FT_DEBUG_LEVEL_TRACE p_old = p; GET_UTF8_CHAR( ch, p_old ); #endif p = af_shaper_get_cluster( p, &metrics->root, shaper_buf, &num_idx ); if ( !num_idx ) { FT_TRACE5(( " U+%04lX unavailable\n", ch )); continue; } if ( AF_LATIN_IS_TOP_BLUE( bs ) ) best_y_extremum = FT_INT_MIN; else best_y_extremum = FT_INT_MAX; /* iterate over all glyph elements of the character cluster */ /* and get the data of the `biggest' one */ for ( i = 0; i < num_idx; i++ ) { FT_Pos best_y; FT_Bool round = 0; /* load the character in the face -- skip unknown or empty ones */ glyph_index = af_shaper_get_elem( &metrics->root, shaper_buf, i, NULL, &y_offset ); if ( glyph_index == 0 ) { FT_TRACE5(( " U+%04lX unavailable\n", ch )); continue; } error = FT_Load_Glyph( face, glyph_index, FT_LOAD_NO_SCALE ); outline = face->glyph->outline; /* reject glyphs that don't produce any rendering */ if ( error || outline.n_points <= 2 ) { #ifdef FT_DEBUG_LEVEL_TRACE if ( num_idx == 1 ) FT_TRACE5(( " U+%04lX contains no (usable) outlines\n", ch )); else FT_TRACE5(( " component %d of cluster starting with U+%04lX" " contains no (usable) outlines\n", i, ch )); #endif continue; } /* now compute min or max point indices and coordinates */ points = outline.points; best_point = -1; best_contour_first = -1; best_contour_last = -1; best_y = 0; /* make compiler happy */ { FT_Int nn; FT_Int pp, first, last; last = -1; for ( nn = 0; nn < outline.n_contours; nn++ ) { first = last + 1; last = outline.contours[nn]; /* Avoid single-point contours since they are never */ /* rasterized. In some fonts, they correspond to mark */ /* attachment points that are way outside of the glyph's */ /* real outline. */ if ( last <= first ) continue; if ( AF_LATIN_IS_TOP_BLUE( bs ) || AF_LATIN_IS_SUB_TOP_BLUE( bs ) ) { for ( pp = first; pp <= last; pp++ ) { if ( best_point < 0 || points[pp].y > best_y ) { best_point = pp; best_y = points[pp].y; ascender = FT_MAX( ascender, best_y + y_offset ); } else descender = FT_MIN( descender, points[pp].y + y_offset ); } } else { for ( pp = first; pp <= last; pp++ ) { if ( best_point < 0 || points[pp].y < best_y ) { best_point = pp; best_y = points[pp].y; descender = FT_MIN( descender, best_y + y_offset ); } else ascender = FT_MAX( ascender, points[pp].y + y_offset ); } } if ( best_point > best_contour_last ) { best_contour_first = first; best_contour_last = last; } } } /* now check whether the point belongs to a straight or round */ /* segment; we first need to find in which contour the extremum */ /* lies, then inspect its previous and next points */ if ( best_point >= 0 ) { FT_Pos best_x = points[best_point].x; FT_Int prev, next; FT_Int best_segment_first, best_segment_last; FT_Int best_on_point_first, best_on_point_last; FT_Pos dist; best_segment_first = best_point; best_segment_last = best_point; if ( FT_CURVE_TAG( outline.tags[best_point] ) == FT_CURVE_TAG_ON ) { best_on_point_first = best_point; best_on_point_last = best_point; } else { best_on_point_first = -1; best_on_point_last = -1; } /* look for the previous and next points on the contour */ /* that are not on the same Y coordinate, then threshold */ /* the `closeness'... */ prev = best_point; next = prev; do { if ( prev > best_contour_first ) prev--; else prev = best_contour_last; dist = FT_ABS( points[prev].y - best_y ); /* accept a small distance or a small angle (both values are */ /* heuristic; value 20 corresponds to approx. 2.9 degrees) */ if ( dist > 5 ) if ( FT_ABS( points[prev].x - best_x ) <= 20 * dist ) break; best_segment_first = prev; if ( FT_CURVE_TAG( outline.tags[prev] ) == FT_CURVE_TAG_ON ) { best_on_point_first = prev; if ( best_on_point_last < 0 ) best_on_point_last = prev; } } while ( prev != best_point ); do { if ( next < best_contour_last ) next++; else next = best_contour_first; dist = FT_ABS( points[next].y - best_y ); if ( dist > 5 ) if ( FT_ABS( points[next].x - best_x ) <= 20 * dist ) break; best_segment_last = next; if ( FT_CURVE_TAG( outline.tags[next] ) == FT_CURVE_TAG_ON ) { best_on_point_last = next; if ( best_on_point_first < 0 ) best_on_point_first = next; } } while ( next != best_point ); if ( AF_LATIN_IS_LONG_BLUE( bs ) ) { /* If this flag is set, we have an additional constraint to */ /* get the blue zone distance: Find a segment of the topmost */ /* (or bottommost) contour that is longer than a heuristic */ /* threshold. This ensures that small bumps in the outline */ /* are ignored (for example, the `vertical serifs' found in */ /* many Hebrew glyph designs). */ /* If this segment is long enough, we are done. Otherwise, */ /* search the segment next to the extremum that is long */ /* enough, has the same direction, and a not too large */ /* vertical distance from the extremum. Note that the */ /* algorithm doesn't check whether the found segment is */ /* actually the one (vertically) nearest to the extremum. */ /* heuristic threshold value */ FT_Pos length_threshold = metrics->units_per_em / 25; dist = FT_ABS( points[best_segment_last].x - points[best_segment_first].x ); if ( dist < length_threshold && best_segment_last - best_segment_first + 2 <= best_contour_last - best_contour_first ) { /* heuristic threshold value */ FT_Pos height_threshold = metrics->units_per_em / 4; FT_Int first; FT_Int last; FT_Bool hit; /* we intentionally declare these two variables */ /* outside of the loop since various compilers emit */ /* incorrect warning messages otherwise, talking about */ /* `possibly uninitialized variables' */ FT_Int p_first = 0; /* make compiler happy */ FT_Int p_last = 0; FT_Bool left2right; /* compute direction */ prev = best_point; do { if ( prev > best_contour_first ) prev--; else prev = best_contour_last; if ( points[prev].x != best_x ) break; } while ( prev != best_point ); /* skip glyph for the degenerate case */ if ( prev == best_point ) continue; left2right = FT_BOOL( points[prev].x < points[best_point].x ); first = best_segment_last; last = first; hit = 0; do { FT_Bool l2r; FT_Pos d; if ( !hit ) { /* no hit; adjust first point */ first = last; /* also adjust first and last on point */ if ( FT_CURVE_TAG( outline.tags[first] ) == FT_CURVE_TAG_ON ) { p_first = first; p_last = first; } else { p_first = -1; p_last = -1; } hit = 1; } if ( last < best_contour_last ) last++; else last = best_contour_first; if ( FT_ABS( best_y - points[first].y ) > height_threshold ) { /* vertical distance too large */ hit = 0; continue; } /* same test as above */ dist = FT_ABS( points[last].y - points[first].y ); if ( dist > 5 ) if ( FT_ABS( points[last].x - points[first].x ) <= 20 * dist ) { hit = 0; continue; } if ( FT_CURVE_TAG( outline.tags[last] ) == FT_CURVE_TAG_ON ) { p_last = last; if ( p_first < 0 ) p_first = last; } l2r = FT_BOOL( points[first].x < points[last].x ); d = FT_ABS( points[last].x - points[first].x ); if ( l2r == left2right && d >= length_threshold ) { /* all constraints are met; update segment after */ /* finding its end */ do { if ( last < best_contour_last ) last++; else last = best_contour_first; d = FT_ABS( points[last].y - points[first].y ); if ( d > 5 ) if ( FT_ABS( points[next].x - points[first].x ) <= 20 * dist ) { if ( last > best_contour_first ) last--; else last = best_contour_last; break; } p_last = last; if ( FT_CURVE_TAG( outline.tags[last] ) == FT_CURVE_TAG_ON ) { p_last = last; if ( p_first < 0 ) p_first = last; } } while ( last != best_segment_first ); best_y = points[first].y; best_segment_first = first; best_segment_last = last; best_on_point_first = p_first; best_on_point_last = p_last; break; } } while ( last != best_segment_first ); } } /* for computing blue zones, we add the y offset as returned */ /* by the currently used OpenType feature -- for example, */ /* superscript glyphs might be identical to subscript glyphs */ /* with a vertical shift */ best_y += y_offset; #ifdef FT_DEBUG_LEVEL_TRACE if ( num_idx == 1 ) FT_TRACE5(( " U+%04lX: best_y = %5ld", ch, best_y )); else FT_TRACE5(( " component %d of cluster starting with U+%04lX:" " best_y = %5ld", i, ch, best_y )); #endif /* now set the `round' flag depending on the segment's kind: */ /* */ /* - if the horizontal distance between the first and last */ /* `on' point is larger than a heuristic threshold */ /* we have a flat segment */ /* - if either the first or the last point of the segment is */ /* an `off' point, the segment is round, otherwise it is */ /* flat */ if ( best_on_point_first >= 0 && best_on_point_last >= 0 && ( FT_ABS( points[best_on_point_last].x - points[best_on_point_first].x ) ) > flat_threshold ) round = 0; else round = FT_BOOL( FT_CURVE_TAG( outline.tags[best_segment_first] ) != FT_CURVE_TAG_ON || FT_CURVE_TAG( outline.tags[best_segment_last] ) != FT_CURVE_TAG_ON ); if ( round && AF_LATIN_IS_NEUTRAL_BLUE( bs ) ) { /* only use flat segments for a neutral blue zone */ FT_TRACE5(( " (round, skipped)\n" )); continue; } FT_TRACE5(( " (%s)\n", round ? "round" : "flat" )); } if ( AF_LATIN_IS_TOP_BLUE( bs ) ) { if ( best_y > best_y_extremum ) { best_y_extremum = best_y; best_round = round; } } else { if ( best_y < best_y_extremum ) { best_y_extremum = best_y; best_round = round; } } } /* end for loop */ if ( !( best_y_extremum == FT_INT_MIN || best_y_extremum == FT_INT_MAX ) ) { if ( best_round ) rounds[num_rounds++] = best_y_extremum; else flats[num_flats++] = best_y_extremum; } } /* end while loop */ if ( num_flats == 0 && num_rounds == 0 ) { /* * we couldn't find a single glyph to compute this blue zone, * we will simply ignore it then */ FT_TRACE5(( " empty\n" )); continue; } /* we have computed the contents of the `rounds' and `flats' tables, */ /* now determine the reference and overshoot position of the blue -- */ /* we simply take the median value after a simple sort */ af_sort_pos( num_rounds, rounds ); af_sort_pos( num_flats, flats ); blue = &axis->blues[axis->blue_count]; blue_ref = &blue->ref.org; blue_shoot = &blue->shoot.org; axis->blue_count++; if ( num_flats == 0 ) { *blue_ref = *blue_shoot = rounds[num_rounds / 2]; } else if ( num_rounds == 0 ) { *blue_ref = *blue_shoot = flats[num_flats / 2]; } else { *blue_ref = flats [num_flats / 2]; *blue_shoot = rounds[num_rounds / 2]; } /* there are sometimes problems: if the overshoot position of top */ /* zones is under its reference position, or the opposite for bottom */ /* zones. We must thus check everything there and correct the errors */ if ( *blue_shoot != *blue_ref ) { FT_Pos ref = *blue_ref; FT_Pos shoot = *blue_shoot; FT_Bool over_ref = FT_BOOL( shoot > ref ); if ( ( AF_LATIN_IS_TOP_BLUE( bs ) || AF_LATIN_IS_SUB_TOP_BLUE( bs) ) ^ over_ref ) { *blue_ref = *blue_shoot = ( shoot + ref ) / 2; FT_TRACE5(( " [overshoot smaller than reference," " taking mean value]\n" )); } } blue->ascender = ascender; blue->descender = descender; blue->flags = 0; if ( AF_LATIN_IS_TOP_BLUE( bs ) ) blue->flags |= AF_LATIN_BLUE_TOP; if ( AF_LATIN_IS_SUB_TOP_BLUE( bs ) ) blue->flags |= AF_LATIN_BLUE_SUB_TOP; if ( AF_LATIN_IS_NEUTRAL_BLUE( bs ) ) blue->flags |= AF_LATIN_BLUE_NEUTRAL; /* * The following flag is used later to adjust the y and x scales * in order to optimize the pixel grid alignment of the top of small * letters. */ if ( AF_LATIN_IS_X_HEIGHT_BLUE( bs ) ) blue->flags |= AF_LATIN_BLUE_ADJUSTMENT; FT_TRACE5(( " -> reference = %ld\n", *blue_ref )); FT_TRACE5(( " overshoot = %ld\n", *blue_shoot )); } /* end for loop */ af_shaper_buf_destroy( face, shaper_buf ); if ( axis->blue_count ) { /* we finally check whether blue zones are ordered; */ /* `ref' and `shoot' values of two blue zones must not overlap */ FT_UInt i; AF_LatinBlue blue_sorted[AF_BLUE_STRINGSET_MAX_LEN]; for ( i = 0; i < axis->blue_count; i++ ) blue_sorted[i] = &axis->blues[i]; /* sort bottoms of blue zones... */ af_latin_sort_blue( axis->blue_count, blue_sorted ); /* ...and adjust top values if necessary */ for ( i = 0; i < axis->blue_count - 1; i++ ) { FT_Pos* a; FT_Pos* b; #ifdef FT_DEBUG_LEVEL_TRACE FT_Bool a_is_top = 0; #endif if ( blue_sorted[i]->flags & ( AF_LATIN_BLUE_TOP | AF_LATIN_BLUE_SUB_TOP ) ) { a = &blue_sorted[i]->shoot.org; #ifdef FT_DEBUG_LEVEL_TRACE a_is_top = 1; #endif } else a = &blue_sorted[i]->ref.org; if ( blue_sorted[i + 1]->flags & ( AF_LATIN_BLUE_TOP | AF_LATIN_BLUE_SUB_TOP ) ) b = &blue_sorted[i + 1]->shoot.org; else b = &blue_sorted[i + 1]->ref.org; if ( *a > *b ) { *a = *b; FT_TRACE5(( "blue zone overlap:" " adjusting %s %td to %ld\n", a_is_top ? "overshoot" : "reference", blue_sorted[i] - axis->blues, *a )); } } FT_TRACE5(( "\n" )); return 0; } else { /* disable hinting for the current style if there are no blue zones */ AF_FaceGlobals globals = metrics->root.globals; FT_UShort* gstyles = globals->glyph_styles; FT_UInt i; FT_TRACE5(( "no blue zones found:" " hinting disabled for this style\n" )); for ( i = 0; i < globals->glyph_count; i++ ) { if ( ( gstyles[i] & AF_STYLE_MASK ) == sc->style ) gstyles[i] = AF_STYLE_NONE_DFLT; } FT_TRACE5(( "\n" )); return 1; } } /* Check whether all ASCII digits have the same advance width. */ FT_LOCAL_DEF( void ) af_latin_metrics_check_digits( AF_LatinMetrics metrics, FT_Face face ) { FT_Bool started = 0, same_width = 1; FT_Long advance = 0, old_advance = 0; /* If HarfBuzz is not available, we need a pointer to a single */ /* unsigned long value. */ #ifdef FT_CONFIG_OPTION_USE_HARFBUZZ void* shaper_buf; #else FT_ULong shaper_buf_; void* shaper_buf = &shaper_buf_; #endif /* in all supported charmaps, digits have character codes 0x30-0x39 */ const char digits[] = "0 1 2 3 4 5 6 7 8 9"; const char* p; p = digits; #ifdef FT_CONFIG_OPTION_USE_HARFBUZZ shaper_buf = af_shaper_buf_create( face ); #endif while ( *p ) { FT_ULong glyph_index; unsigned int num_idx; /* reject input that maps to more than a single glyph */ p = af_shaper_get_cluster( p, &metrics->root, shaper_buf, &num_idx ); if ( num_idx > 1 ) continue; glyph_index = af_shaper_get_elem( &metrics->root, shaper_buf, 0, &advance, NULL ); if ( !glyph_index ) continue; if ( started ) { if ( advance != old_advance ) { same_width = 0; break; } } else { old_advance = advance; started = 1; } } af_shaper_buf_destroy( face, shaper_buf ); metrics->root.digits_have_same_width = same_width; } /* Initialize global metrics. */ FT_LOCAL_DEF( FT_Error ) af_latin_metrics_init( AF_StyleMetrics metrics_, /* AF_LatinMetrics */ FT_Face face ) { AF_LatinMetrics metrics = (AF_LatinMetrics)metrics_; FT_Error error = FT_Err_Ok; FT_CharMap oldmap = face->charmap; metrics->units_per_em = face->units_per_EM; if ( !FT_Select_Charmap( face, FT_ENCODING_UNICODE ) ) { af_latin_metrics_init_widths( metrics, face ); if ( af_latin_metrics_init_blues( metrics, face ) ) { /* use internal error code to indicate missing blue zones */ error = -1; goto Exit; } af_latin_metrics_check_digits( metrics, face ); } Exit: face->charmap = oldmap; return error; } /* Adjust scaling value, then scale and shift widths */ /* and blue zones (if applicable) for given dimension. */ static void af_latin_metrics_scale_dim( AF_LatinMetrics metrics, AF_Scaler scaler, AF_Dimension dim ) { FT_Fixed scale; FT_Pos delta; AF_LatinAxis axis; FT_UInt nn; if ( dim == AF_DIMENSION_HORZ ) { scale = scaler->x_scale; delta = scaler->x_delta; } else { scale = scaler->y_scale; delta = scaler->y_delta; } axis = &metrics->axis[dim]; if ( axis->org_scale == scale && axis->org_delta == delta ) return; axis->org_scale = scale; axis->org_delta = delta; /* * correct X and Y scale to optimize the alignment of the top of small * letters to the pixel grid */ { AF_LatinAxis Axis = &metrics->axis[AF_DIMENSION_VERT]; AF_LatinBlue blue = NULL; for ( nn = 0; nn < Axis->blue_count; nn++ ) { if ( Axis->blues[nn].flags & AF_LATIN_BLUE_ADJUSTMENT ) { blue = &Axis->blues[nn]; break; } } if ( blue ) { FT_Pos scaled; FT_Pos threshold; FT_Pos fitted; FT_UInt limit; FT_UInt ppem; scaled = FT_MulFix( blue->shoot.org, scale ); ppem = metrics->root.scaler.face->size->metrics.x_ppem; limit = metrics->root.globals->increase_x_height; threshold = 40; /* if the `increase-x-height' property is active, */ /* we round up much more often */ if ( limit && ppem <= limit && ppem >= AF_PROP_INCREASE_X_HEIGHT_MIN ) threshold = 52; fitted = ( scaled + threshold ) & ~63; if ( scaled != fitted ) { #if 0 if ( dim == AF_DIMENSION_HORZ ) { if ( fitted < scaled ) scale -= scale / 50; /* scale *= 0.98 */ } else #endif if ( dim == AF_DIMENSION_VERT ) { FT_Pos max_height; FT_Pos dist; FT_Fixed new_scale; new_scale = FT_MulDiv( scale, fitted, scaled ); /* the scaling should not change the result by more than two pixels */ max_height = metrics->units_per_em; for ( nn = 0; nn < Axis->blue_count; nn++ ) { max_height = FT_MAX( max_height, Axis->blues[nn].ascender ); max_height = FT_MAX( max_height, -Axis->blues[nn].descender ); } dist = FT_MulFix( max_height, new_scale - scale ); if ( -128 < dist && dist < 128 ) { FT_TRACE5(( "af_latin_metrics_scale_dim:" " x height alignment (style `%s'):\n", af_style_names[metrics->root.style_class->style] )); FT_TRACE5(( " " " vertical scaling changed" " from %.5f to %.5f (by %ld%%)\n", (double)scale / 65536, (double)new_scale / 65536, ( fitted - scaled ) * 100 / scaled )); FT_TRACE5(( "\n" )); scale = new_scale; } #ifdef FT_DEBUG_LEVEL_TRACE else { FT_TRACE5(( "af_latin_metrics_scale_dim:" " x height alignment (style `%s'):\n", af_style_names[metrics->root.style_class->style] )); FT_TRACE5(( " " " excessive vertical scaling abandoned\n" )); FT_TRACE5(( "\n" )); } #endif } } } } axis->scale = scale; axis->delta = delta; if ( dim == AF_DIMENSION_HORZ ) { metrics->root.scaler.x_scale = scale; metrics->root.scaler.x_delta = delta; } else { metrics->root.scaler.y_scale = scale; metrics->root.scaler.y_delta = delta; } FT_TRACE5(( "%s widths (style `%s')\n", dim == AF_DIMENSION_HORZ ? "horizontal" : "vertical", af_style_names[metrics->root.style_class->style] )); /* scale the widths */ for ( nn = 0; nn < axis->width_count; nn++ ) { AF_Width width = axis->widths + nn; width->cur = FT_MulFix( width->org, scale ); width->fit = width->cur; FT_TRACE5(( " %ld scaled to %.2f\n", width->org, (double)width->cur / 64 )); } FT_TRACE5(( "\n" )); /* an extra-light axis corresponds to a standard width that is */ /* smaller than 5/8 pixels */ axis->extra_light = FT_BOOL( FT_MulFix( axis->standard_width, scale ) < 32 + 8 ); #ifdef FT_DEBUG_LEVEL_TRACE if ( axis->extra_light ) { FT_TRACE5(( "`%s' style is extra light (at current resolution)\n", af_style_names[metrics->root.style_class->style] )); FT_TRACE5(( "\n" )); } #endif if ( dim == AF_DIMENSION_VERT ) { #ifdef FT_DEBUG_LEVEL_TRACE if ( axis->blue_count ) FT_TRACE5(( "blue zones (style `%s')\n", af_style_names[metrics->root.style_class->style] )); #endif /* scale the blue zones */ for ( nn = 0; nn < axis->blue_count; nn++ ) { AF_LatinBlue blue = &axis->blues[nn]; FT_Pos dist; blue->ref.cur = FT_MulFix( blue->ref.org, scale ) + delta; blue->ref.fit = blue->ref.cur; blue->shoot.cur = FT_MulFix( blue->shoot.org, scale ) + delta; blue->shoot.fit = blue->shoot.cur; blue->flags &= ~AF_LATIN_BLUE_ACTIVE; /* a blue zone is only active if it is less than 3/4 pixels tall */ dist = FT_MulFix( blue->ref.org - blue->shoot.org, scale ); if ( dist <= 48 && dist >= -48 ) { #if 0 FT_Pos delta1; #endif FT_Pos delta2; /* use discrete values for blue zone widths */ #if 0 /* generic, original code */ delta1 = blue->shoot.org - blue->ref.org; delta2 = delta1; if ( delta1 < 0 ) delta2 = -delta2; delta2 = FT_MulFix( delta2, scale ); if ( delta2 < 32 ) delta2 = 0; else if ( delta2 < 64 ) delta2 = 32 + ( ( ( delta2 - 32 ) + 16 ) & ~31 ); else delta2 = FT_PIX_ROUND( delta2 ); if ( delta1 < 0 ) delta2 = -delta2; blue->ref.fit = FT_PIX_ROUND( blue->ref.cur ); blue->shoot.fit = blue->ref.fit + delta2; #else /* simplified version due to abs(dist) <= 48 */ delta2 = dist; if ( dist < 0 ) delta2 = -delta2; if ( delta2 < 32 ) delta2 = 0; else if ( delta2 < 48 ) delta2 = 32; else delta2 = 64; if ( dist < 0 ) delta2 = -delta2; blue->ref.fit = FT_PIX_ROUND( blue->ref.cur ); blue->shoot.fit = blue->ref.fit - delta2; #endif blue->flags |= AF_LATIN_BLUE_ACTIVE; } } /* use sub-top blue zone only if it doesn't overlap with */ /* another (non-sup-top) blue zone; otherwise, the */ /* effect would be similar to a neutral blue zone, which */ /* is not desired here */ for ( nn = 0; nn < axis->blue_count; nn++ ) { AF_LatinBlue blue = &axis->blues[nn]; FT_UInt i; if ( !( blue->flags & AF_LATIN_BLUE_SUB_TOP ) ) continue; if ( !( blue->flags & AF_LATIN_BLUE_ACTIVE ) ) continue; for ( i = 0; i < axis->blue_count; i++ ) { AF_LatinBlue b = &axis->blues[i]; if ( b->flags & AF_LATIN_BLUE_SUB_TOP ) continue; if ( !( b->flags & AF_LATIN_BLUE_ACTIVE ) ) continue; if ( b->ref.fit <= blue->shoot.fit && b->shoot.fit >= blue->ref.fit ) { blue->flags &= ~AF_LATIN_BLUE_ACTIVE; break; } } } #ifdef FT_DEBUG_LEVEL_TRACE for ( nn = 0; nn < axis->blue_count; nn++ ) { AF_LatinBlue blue = &axis->blues[nn]; FT_TRACE5(( " reference %d: %ld scaled to %.2f%s\n", nn, blue->ref.org, (double)blue->ref.fit / 64, ( blue->flags & AF_LATIN_BLUE_ACTIVE ) ? "" : " (inactive)" )); FT_TRACE5(( " overshoot %d: %ld scaled to %.2f%s\n", nn, blue->shoot.org, (double)blue->shoot.fit / 64, ( blue->flags & AF_LATIN_BLUE_ACTIVE ) ? "" : " (inactive)" )); } #endif } } /* Scale global values in both directions. */ FT_LOCAL_DEF( void ) af_latin_metrics_scale( AF_StyleMetrics metrics_, /* AF_LatinMetrics */ AF_Scaler scaler ) { AF_LatinMetrics metrics = (AF_LatinMetrics)metrics_; metrics->root.scaler.render_mode = scaler->render_mode; metrics->root.scaler.face = scaler->face; metrics->root.scaler.flags = scaler->flags; af_latin_metrics_scale_dim( metrics, scaler, AF_DIMENSION_HORZ ); af_latin_metrics_scale_dim( metrics, scaler, AF_DIMENSION_VERT ); } /* Extract standard_width from writing system/script specific */ /* metrics class. */ FT_CALLBACK_DEF( void ) af_latin_get_standard_widths( AF_StyleMetrics metrics_, /* AF_LatinMetrics */ FT_Pos* stdHW, FT_Pos* stdVW ) { AF_LatinMetrics metrics = (AF_LatinMetrics)metrics_; if ( stdHW ) *stdHW = metrics->axis[AF_DIMENSION_VERT].standard_width; if ( stdVW ) *stdVW = metrics->axis[AF_DIMENSION_HORZ].standard_width; } /*************************************************************************/ /*************************************************************************/ /***** *****/ /***** L A T I N G L Y P H A N A L Y S I S *****/ /***** *****/ /*************************************************************************/ /*************************************************************************/ /* Walk over all contours and compute its segments. */ FT_LOCAL_DEF( FT_Error ) af_latin_hints_compute_segments( AF_GlyphHints hints, AF_Dimension dim ) { AF_LatinMetrics metrics = (AF_LatinMetrics)hints->metrics; AF_AxisHints axis = &hints->axis[dim]; FT_Memory memory = hints->memory; FT_Error error = FT_Err_Ok; AF_Segment segment = NULL; AF_SegmentRec seg0; AF_Point* contour = hints->contours; AF_Point* contour_limit = contour + hints->num_contours; AF_Direction major_dir, segment_dir; FT_Pos flat_threshold = FLAT_THRESHOLD( metrics->units_per_em ); FT_ZERO( &seg0 ); seg0.score = 32000; seg0.flags = AF_EDGE_NORMAL; major_dir = (AF_Direction)FT_ABS( axis->major_dir ); segment_dir = major_dir; axis->num_segments = 0; /* set up (u,v) in each point */ if ( dim == AF_DIMENSION_HORZ ) { AF_Point point = hints->points; AF_Point limit = point + hints->num_points; for ( ; point < limit; point++ ) { point->u = point->fx; point->v = point->fy; } } else { AF_Point point = hints->points; AF_Point limit = point + hints->num_points; for ( ; point < limit; point++ ) { point->u = point->fy; point->v = point->fx; } } /* do each contour separately */ for ( ; contour < contour_limit; contour++ ) { AF_Point point = contour[0]; AF_Point last = point->prev; int on_edge = 0; /* we call values measured along a segment (point->v) */ /* `coordinates', and values orthogonal to it (point->u) */ /* `positions' */ FT_Pos min_pos = 32000; FT_Pos max_pos = -32000; FT_Pos min_coord = 32000; FT_Pos max_coord = -32000; FT_UShort min_flags = AF_FLAG_NONE; FT_UShort max_flags = AF_FLAG_NONE; FT_Pos min_on_coord = 32000; FT_Pos max_on_coord = -32000; FT_Bool passed; AF_Segment prev_segment = NULL; FT_Pos prev_min_pos = min_pos; FT_Pos prev_max_pos = max_pos; FT_Pos prev_min_coord = min_coord; FT_Pos prev_max_coord = max_coord; FT_UShort prev_min_flags = min_flags; FT_UShort prev_max_flags = max_flags; FT_Pos prev_min_on_coord = min_on_coord; FT_Pos prev_max_on_coord = max_on_coord; if ( FT_ABS( last->out_dir ) == major_dir && FT_ABS( point->out_dir ) == major_dir ) { /* we are already on an edge, try to locate its start */ last = point; for (;;) { point = point->prev; if ( FT_ABS( point->out_dir ) != major_dir ) { point = point->next; break; } if ( point == last ) break; } } last = point; passed = 0; for (;;) { FT_Pos u, v; if ( on_edge ) { /* get minimum and maximum position */ u = point->u; if ( u < min_pos ) min_pos = u; if ( u > max_pos ) max_pos = u; /* get minimum and maximum coordinate together with flags */ v = point->v; if ( v < min_coord ) { min_coord = v; min_flags = point->flags; } if ( v > max_coord ) { max_coord = v; max_flags = point->flags; } /* get minimum and maximum coordinate of `on' points */ if ( !( point->flags & AF_FLAG_CONTROL ) ) { v = point->v; if ( v < min_on_coord ) min_on_coord = v; if ( v > max_on_coord ) max_on_coord = v; } if ( point->out_dir != segment_dir || point == last ) { /* check whether the new segment's start point is identical to */ /* the previous segment's end point; for example, this might */ /* happen for spikes */ if ( !prev_segment || segment->first != prev_segment->last ) { /* points are different: we are just leaving an edge, thus */ /* record a new segment */ segment->last = point; segment->pos = (FT_Short)( ( min_pos + max_pos ) >> 1 ); segment->delta = (FT_Short)( ( max_pos - min_pos ) >> 1 ); /* a segment is round if either its first or last point */ /* is a control point, and the length of the on points */ /* inbetween doesn't exceed a heuristic limit */ if ( ( min_flags | max_flags ) & AF_FLAG_CONTROL && ( max_on_coord - min_on_coord ) < flat_threshold ) segment->flags |= AF_EDGE_ROUND; segment->min_coord = (FT_Short)min_coord; segment->max_coord = (FT_Short)max_coord; segment->height = segment->max_coord - segment->min_coord; prev_segment = segment; prev_min_pos = min_pos; prev_max_pos = max_pos; prev_min_coord = min_coord; prev_max_coord = max_coord; prev_min_flags = min_flags; prev_max_flags = max_flags; prev_min_on_coord = min_on_coord; prev_max_on_coord = max_on_coord; } else { /* points are the same: we don't create a new segment but */ /* merge the current segment with the previous one */ if ( prev_segment->last->in_dir == point->in_dir ) { /* we have identical directions (this can happen for */ /* degenerate outlines that move zig-zag along the main */ /* axis without changing the coordinate value of the other */ /* axis, and where the segments have just been merged): */ /* unify segments */ /* update constraints */ if ( prev_min_pos < min_pos ) min_pos = prev_min_pos; if ( prev_max_pos > max_pos ) max_pos = prev_max_pos; if ( prev_min_coord < min_coord ) { min_coord = prev_min_coord; min_flags = prev_min_flags; } if ( prev_max_coord > max_coord ) { max_coord = prev_max_coord; max_flags = prev_max_flags; } if ( prev_min_on_coord < min_on_coord ) min_on_coord = prev_min_on_coord; if ( prev_max_on_coord > max_on_coord ) max_on_coord = prev_max_on_coord; prev_segment->last = point; prev_segment->pos = (FT_Short)( ( min_pos + max_pos ) >> 1 ); prev_segment->delta = (FT_Short)( ( max_pos - min_pos ) >> 1 ); if ( ( min_flags | max_flags ) & AF_FLAG_CONTROL && ( max_on_coord - min_on_coord ) < flat_threshold ) prev_segment->flags |= AF_EDGE_ROUND; else prev_segment->flags &= ~AF_EDGE_ROUND; prev_segment->min_coord = (FT_Short)min_coord; prev_segment->max_coord = (FT_Short)max_coord; prev_segment->height = prev_segment->max_coord - prev_segment->min_coord; } else { /* we have different directions; use the properties of the */ /* longer segment and discard the other one */ if ( FT_ABS( prev_max_coord - prev_min_coord ) > FT_ABS( max_coord - min_coord ) ) { /* discard current segment */ if ( min_pos < prev_min_pos ) prev_min_pos = min_pos; if ( max_pos > prev_max_pos ) prev_max_pos = max_pos; prev_segment->last = point; prev_segment->pos = (FT_Short)( ( prev_min_pos + prev_max_pos ) >> 1 ); prev_segment->delta = (FT_Short)( ( prev_max_pos - prev_min_pos ) >> 1 ); } else { /* discard previous segment */ if ( prev_min_pos < min_pos ) min_pos = prev_min_pos; if ( prev_max_pos > max_pos ) max_pos = prev_max_pos; segment->last = point; segment->pos = (FT_Short)( ( min_pos + max_pos ) >> 1 ); segment->delta = (FT_Short)( ( max_pos - min_pos ) >> 1 ); if ( ( min_flags | max_flags ) & AF_FLAG_CONTROL && ( max_on_coord - min_on_coord ) < flat_threshold ) segment->flags |= AF_EDGE_ROUND; segment->min_coord = (FT_Short)min_coord; segment->max_coord = (FT_Short)max_coord; segment->height = segment->max_coord - segment->min_coord; *prev_segment = *segment; prev_min_pos = min_pos; prev_max_pos = max_pos; prev_min_coord = min_coord; prev_max_coord = max_coord; prev_min_flags = min_flags; prev_max_flags = max_flags; prev_min_on_coord = min_on_coord; prev_max_on_coord = max_on_coord; } } axis->num_segments--; } on_edge = 0; segment = NULL; /* fall through */ } } /* now exit if we are at the start/end point */ if ( point == last ) { if ( passed ) break; passed = 1; } /* if we are not on an edge, check whether the major direction */ /* coincides with the current point's `out' direction, or */ /* whether we have a single-point contour */ if ( !on_edge && ( FT_ABS( point->out_dir ) == major_dir || point == point->prev ) ) { /* * For efficiency, we restrict the number of segments to 1000, * which is a heuristic value: it is very unlikely that a glyph * with so many segments can be hinted in a sensible way. * Reasons: * * - The glyph has really 1000 segments; this implies that it has * at least 2000 outline points. Assuming 'normal' fonts that * have superfluous points optimized away, viewing such a glyph * only makes sense at large magnifications where hinting * isn't applied anyway. * * - We have a broken glyph. Hinting doesn't make sense in this * case either. */ if ( axis->num_segments > 1000 ) { FT_TRACE0(( "af_latin_hints_compute_segments:" " more than 1000 segments in this glyph;\n" )); FT_TRACE0(( " " " hinting is suppressed\n" )); axis->num_segments = 0; return FT_Err_Ok; } /* this is the start of a new segment! */ segment_dir = (AF_Direction)point->out_dir; error = af_axis_hints_new_segment( axis, memory, &segment ); if ( error ) goto Exit; /* clear all segment fields */ segment[0] = seg0; segment->dir = (FT_Char)segment_dir; segment->first = point; segment->last = point; /* `af_axis_hints_new_segment' reallocates memory, */ /* thus we have to refresh the `prev_segment' pointer */ if ( prev_segment ) prev_segment = segment - 1; min_pos = max_pos = point->u; min_coord = max_coord = point->v; min_flags = max_flags = point->flags; if ( point->flags & AF_FLAG_CONTROL ) { min_on_coord = 32000; max_on_coord = -32000; } else min_on_coord = max_on_coord = point->v; on_edge = 1; if ( point == point->prev ) { /* we have a one-point segment: this is a one-point */ /* contour with `in' and `out' direction set to */ /* AF_DIR_NONE */ segment->pos = (FT_Short)min_pos; if (point->flags & AF_FLAG_CONTROL) segment->flags |= AF_EDGE_ROUND; segment->min_coord = (FT_Short)point->v; segment->max_coord = (FT_Short)point->v; segment->height = 0; on_edge = 0; segment = NULL; } } point = point->next; } } /* contours */ /* now slightly increase the height of segments if this makes */ /* sense -- this is used to better detect and ignore serifs */ { AF_Segment segments = axis->segments; AF_Segment segments_end = FT_OFFSET( segments, axis->num_segments ); for ( segment = segments; segment < segments_end; segment++ ) { AF_Point first = segment->first; AF_Point last = segment->last; FT_Pos first_v = first->v; FT_Pos last_v = last->v; if ( first_v < last_v ) { AF_Point p; p = first->prev; if ( p->v < first_v ) segment->height = (FT_Short)( segment->height + ( ( first_v - p->v ) >> 1 ) ); p = last->next; if ( p->v > last_v ) segment->height = (FT_Short)( segment->height + ( ( p->v - last_v ) >> 1 ) ); } else { AF_Point p; p = first->prev; if ( p->v > first_v ) segment->height = (FT_Short)( segment->height + ( ( p->v - first_v ) >> 1 ) ); p = last->next; if ( p->v < last_v ) segment->height = (FT_Short)( segment->height + ( ( last_v - p->v ) >> 1 ) ); } } } Exit: return error; } /* Link segments to form stems and serifs. If `width_count' and */ /* `widths' are non-zero, use them to fine-tune the scoring function. */ FT_LOCAL_DEF( void ) af_latin_hints_link_segments( AF_GlyphHints hints, FT_UInt width_count, AF_WidthRec* widths, AF_Dimension dim ) { AF_AxisHints axis = &hints->axis[dim]; AF_Segment segments = axis->segments; AF_Segment segment_limit = FT_OFFSET( segments, axis->num_segments ); FT_Pos len_threshold, len_score, dist_score, max_width; AF_Segment seg1, seg2; if ( width_count ) max_width = widths[width_count - 1].org; else max_width = 0; /* a heuristic value to set up a minimum value for overlapping */ len_threshold = AF_LATIN_CONSTANT( hints->metrics, 8 ); if ( len_threshold == 0 ) len_threshold = 1; /* a heuristic value to weight lengths */ len_score = AF_LATIN_CONSTANT( hints->metrics, 6000 ); /* a heuristic value to weight distances (no call to */ /* AF_LATIN_CONSTANT needed, since we work on multiples */ /* of the stem width) */ dist_score = 3000; /* now compare each segment to the others */ for ( seg1 = segments; seg1 < segment_limit; seg1++ ) { if ( seg1->dir != axis->major_dir ) continue; /* search for stems having opposite directions, */ /* with seg1 to the `left' of seg2 */ for ( seg2 = segments; seg2 < segment_limit; seg2++ ) { FT_Pos pos1 = seg1->pos; FT_Pos pos2 = seg2->pos; if ( seg1->dir + seg2->dir == 0 && pos2 > pos1 ) { /* compute distance between the two segments */ FT_Pos min = seg1->min_coord; FT_Pos max = seg1->max_coord; FT_Pos len; if ( min < seg2->min_coord ) min = seg2->min_coord; if ( max > seg2->max_coord ) max = seg2->max_coord; /* compute maximum coordinate difference of the two segments */ /* (that is, how much they overlap) */ len = max - min; if ( len >= len_threshold ) { /* * The score is the sum of two demerits indicating the * `badness' of a fit, measured along the segments' main axis * and orthogonal to it, respectively. * * - The less overlapping along the main axis, the worse it * is, causing a larger demerit. * * - The nearer the orthogonal distance to a stem width, the * better it is, causing a smaller demerit. For simplicity, * however, we only increase the demerit for values that * exceed the largest stem width. */ FT_Pos dist = pos2 - pos1; FT_Pos dist_demerit, score; if ( max_width ) { /* distance demerits are based on multiples of `max_width'; */ /* we scale by 1024 for getting more precision */ FT_Pos delta = ( dist << 10 ) / max_width - ( 1 << 10 ); if ( delta > 10000 ) dist_demerit = 32000; else if ( delta > 0 ) dist_demerit = delta * delta / dist_score; else dist_demerit = 0; } else dist_demerit = dist; /* default if no widths available */ score = dist_demerit + len_score / len; /* and we search for the smallest score */ if ( score < seg1->score ) { seg1->score = score; seg1->link = seg2; } if ( score < seg2->score ) { seg2->score = score; seg2->link = seg1; } } } } } /* now compute the `serif' segments, cf. explanations in `afhints.h' */ for ( seg1 = segments; seg1 < segment_limit; seg1++ ) { seg2 = seg1->link; if ( seg2 ) { if ( seg2->link != seg1 ) { seg1->link = NULL; seg1->serif = seg2->link; } } } } /* Link segments to edges, using feature analysis for selection. */ FT_LOCAL_DEF( FT_Error ) af_latin_hints_compute_edges( AF_GlyphHints hints, AF_Dimension dim ) { AF_AxisHints axis = &hints->axis[dim]; FT_Error error = FT_Err_Ok; FT_Memory memory = hints->memory; AF_LatinAxis laxis = &((AF_LatinMetrics)hints->metrics)->axis[dim]; AF_StyleClass style_class = hints->metrics->style_class; AF_ScriptClass script_class = af_script_classes[style_class->script]; FT_Bool top_to_bottom_hinting = 0; AF_Segment segments = axis->segments; AF_Segment segment_limit = FT_OFFSET( segments, axis->num_segments ); AF_Segment seg; #if 0 AF_Direction up_dir; #endif FT_Fixed scale; FT_Pos edge_distance_threshold; FT_Pos segment_length_threshold; FT_Pos segment_width_threshold; axis->num_edges = 0; scale = ( dim == AF_DIMENSION_HORZ ) ? hints->x_scale : hints->y_scale; #if 0 up_dir = ( dim == AF_DIMENSION_HORZ ) ? AF_DIR_UP : AF_DIR_RIGHT; #endif if ( dim == AF_DIMENSION_VERT ) top_to_bottom_hinting = script_class->top_to_bottom_hinting; /* * We ignore all segments that are less than 1 pixel in length * to avoid many problems with serif fonts. We compute the * corresponding threshold in font units. */ if ( dim == AF_DIMENSION_HORZ ) segment_length_threshold = FT_DivFix( 64, hints->y_scale ); else segment_length_threshold = 0; /* * Similarly, we ignore segments that have a width delta * larger than 0.5px (i.e., a width larger than 1px). */ segment_width_threshold = FT_DivFix( 32, scale ); /********************************************************************** * * We begin by generating a sorted table of edges for the current * direction. To do so, we simply scan each segment and try to find * an edge in our table that corresponds to its position. * * If no edge is found, we create and insert a new edge in the * sorted table. Otherwise, we simply add the segment to the edge's * list which gets processed in the second step to compute the * edge's properties. * * Note that the table of edges is sorted along the segment/edge * position. * */ /* assure that edge distance threshold is at most 0.25px */ edge_distance_threshold = FT_MulFix( laxis->edge_distance_threshold, scale ); if ( edge_distance_threshold > 64 / 4 ) edge_distance_threshold = 64 / 4; edge_distance_threshold = FT_DivFix( edge_distance_threshold, scale ); for ( seg = segments; seg < segment_limit; seg++ ) { AF_Edge found = NULL; FT_UInt ee; /* ignore too short segments, too wide ones, and, in this loop, */ /* one-point segments without a direction */ if ( seg->height < segment_length_threshold || seg->delta > segment_width_threshold || seg->dir == AF_DIR_NONE ) continue; /* A special case for serif edges: If they are smaller than */ /* 1.5 pixels we ignore them. */ if ( seg->serif && 2 * seg->height < 3 * segment_length_threshold ) continue; /* look for an edge corresponding to the segment */ for ( ee = 0; ee < axis->num_edges; ee++ ) { AF_Edge edge = axis->edges + ee; FT_Pos dist; dist = seg->pos - edge->fpos; if ( dist < 0 ) dist = -dist; if ( dist < edge_distance_threshold && edge->dir == seg->dir ) { found = edge; break; } } if ( !found ) { AF_Edge edge; /* insert a new edge in the list and */ /* sort according to the position */ error = af_axis_hints_new_edge( axis, seg->pos, (AF_Direction)seg->dir, top_to_bottom_hinting, memory, &edge ); if ( error ) goto Exit; /* add the segment to the new edge's list */ FT_ZERO( edge ); edge->first = seg; edge->last = seg; edge->dir = seg->dir; edge->fpos = seg->pos; edge->opos = FT_MulFix( seg->pos, scale ); edge->pos = edge->opos; seg->edge_next = seg; } else { /* if an edge was found, simply add the segment to the edge's */ /* list */ seg->edge_next = found->first; found->last->edge_next = seg; found->last = seg; } } /* we loop again over all segments to catch one-point segments */ /* without a direction: if possible, link them to existing edges */ for ( seg = segments; seg < segment_limit; seg++ ) { AF_Edge found = NULL; FT_UInt ee; if ( seg->dir != AF_DIR_NONE ) continue; /* look for an edge corresponding to the segment */ for ( ee = 0; ee < axis->num_edges; ee++ ) { AF_Edge edge = axis->edges + ee; FT_Pos dist; dist = seg->pos - edge->fpos; if ( dist < 0 ) dist = -dist; if ( dist < edge_distance_threshold ) { found = edge; break; } } /* one-point segments without a match are ignored */ if ( found ) { seg->edge_next = found->first; found->last->edge_next = seg; found->last = seg; } } /******************************************************************* * * Good, we now compute each edge's properties according to the * segments found on its position. Basically, these are * * - the edge's main direction * - stem edge, serif edge or both (which defaults to stem then) * - rounded edge, straight or both (which defaults to straight) * - link for edge * */ /* first of all, set the `edge' field in each segment -- this is */ /* required in order to compute edge links */ /* * Note that removing this loop and setting the `edge' field of each * segment directly in the code above slows down execution speed for * some reasons on platforms like the Sun. */ { AF_Edge edges = axis->edges; AF_Edge edge_limit = FT_OFFSET( edges, axis->num_edges ); AF_Edge edge; for ( edge = edges; edge < edge_limit; edge++ ) { seg = edge->first; if ( seg ) do { seg->edge = edge; seg = seg->edge_next; } while ( seg != edge->first ); } /* now compute each edge properties */ for ( edge = edges; edge < edge_limit; edge++ ) { FT_Int is_round = 0; /* does it contain round segments? */ FT_Int is_straight = 0; /* does it contain straight segments? */ #if 0 FT_Pos ups = 0; /* number of upwards segments */ FT_Pos downs = 0; /* number of downwards segments */ #endif seg = edge->first; do { FT_Bool is_serif; /* check for roundness of segment */ if ( seg->flags & AF_EDGE_ROUND ) is_round++; else is_straight++; #if 0 /* check for segment direction */ if ( seg->dir == up_dir ) ups += seg->max_coord - seg->min_coord; else downs += seg->max_coord - seg->min_coord; #endif /* check for links -- if seg->serif is set, then seg->link must */ /* be ignored */ is_serif = FT_BOOL( seg->serif && seg->serif->edge && seg->serif->edge != edge ); if ( ( seg->link && seg->link->edge ) || is_serif ) { AF_Edge edge2; AF_Segment seg2; edge2 = edge->link; seg2 = seg->link; if ( is_serif ) { seg2 = seg->serif; edge2 = edge->serif; } if ( edge2 ) { FT_Pos edge_delta; FT_Pos seg_delta; edge_delta = edge->fpos - edge2->fpos; if ( edge_delta < 0 ) edge_delta = -edge_delta; seg_delta = seg->pos - seg2->pos; if ( seg_delta < 0 ) seg_delta = -seg_delta; if ( seg_delta < edge_delta ) edge2 = seg2->edge; } else edge2 = seg2->edge; if ( is_serif ) { edge->serif = edge2; edge2->flags |= AF_EDGE_SERIF; } else edge->link = edge2; } seg = seg->edge_next; } while ( seg != edge->first ); /* set the round/straight flags */ edge->flags = AF_EDGE_NORMAL; if ( is_round > 0 && is_round >= is_straight ) edge->flags |= AF_EDGE_ROUND; #if 0 /* set the edge's main direction */ edge->dir = AF_DIR_NONE; if ( ups > downs ) edge->dir = (FT_Char)up_dir; else if ( ups < downs ) edge->dir = (FT_Char)-up_dir; else if ( ups == downs ) edge->dir = 0; /* both up and down! */ #endif /* get rid of serifs if link is set */ /* XXX: This gets rid of many unpleasant artefacts! */ /* Example: the `c' in cour.pfa at size 13 */ if ( edge->serif && edge->link ) edge->serif = NULL; } } Exit: return error; } /* Detect segments and edges for given dimension. */ FT_LOCAL_DEF( FT_Error ) af_latin_hints_detect_features( AF_GlyphHints hints, FT_UInt width_count, AF_WidthRec* widths, AF_Dimension dim ) { FT_Error error; error = af_latin_hints_compute_segments( hints, dim ); if ( !error ) { af_latin_hints_link_segments( hints, width_count, widths, dim ); error = af_latin_hints_compute_edges( hints, dim ); } return error; } /* Compute all edges which lie within blue zones. */ static void af_latin_hints_compute_blue_edges( AF_GlyphHints hints, AF_LatinMetrics metrics ) { AF_AxisHints axis = &hints->axis[AF_DIMENSION_VERT]; AF_Edge edge = axis->edges; AF_Edge edge_limit = FT_OFFSET( edge, axis->num_edges ); AF_LatinAxis latin = &metrics->axis[AF_DIMENSION_VERT]; FT_Fixed scale = latin->scale; /* compute which blue zones are active, i.e. have their scaled */ /* size < 3/4 pixels */ /* for each horizontal edge search the blue zone which is closest */ for ( ; edge < edge_limit; edge++ ) { FT_UInt bb; AF_Width best_blue = NULL; FT_Bool best_blue_is_neutral = 0; FT_Pos best_dist; /* initial threshold */ /* compute the initial threshold as a fraction of the EM size */ /* (the value 40 is heuristic) */ best_dist = FT_MulFix( metrics->units_per_em / 40, scale ); /* assure a minimum distance of 0.5px */ if ( best_dist > 64 / 2 ) best_dist = 64 / 2; for ( bb = 0; bb < latin->blue_count; bb++ ) { AF_LatinBlue blue = latin->blues + bb; FT_Bool is_top_blue, is_neutral_blue, is_major_dir; /* skip inactive blue zones (i.e., those that are too large) */ if ( !( blue->flags & AF_LATIN_BLUE_ACTIVE ) ) continue; /* if it is a top zone, check for right edges (against the major */ /* direction); if it is a bottom zone, check for left edges (in */ /* the major direction) -- this assumes the TrueType convention */ /* for the orientation of contours */ is_top_blue = (FT_Byte)( ( blue->flags & ( AF_LATIN_BLUE_TOP | AF_LATIN_BLUE_SUB_TOP ) ) != 0 ); is_neutral_blue = (FT_Byte)( ( blue->flags & AF_LATIN_BLUE_NEUTRAL ) != 0); is_major_dir = FT_BOOL( edge->dir == axis->major_dir ); /* neutral blue zones are handled for both directions */ if ( is_top_blue ^ is_major_dir || is_neutral_blue ) { FT_Pos dist; /* first of all, compare it to the reference position */ dist = edge->fpos - blue->ref.org; if ( dist < 0 ) dist = -dist; dist = FT_MulFix( dist, scale ); if ( dist < best_dist ) { best_dist = dist; best_blue = &blue->ref; best_blue_is_neutral = is_neutral_blue; } /* now compare it to the overshoot position and check whether */ /* the edge is rounded, and whether the edge is over the */ /* reference position of a top zone, or under the reference */ /* position of a bottom zone (provided we don't have a */ /* neutral blue zone) */ if ( edge->flags & AF_EDGE_ROUND && dist != 0 && !is_neutral_blue ) { FT_Bool is_under_ref = FT_BOOL( edge->fpos < blue->ref.org ); if ( is_top_blue ^ is_under_ref ) { dist = edge->fpos - blue->shoot.org; if ( dist < 0 ) dist = -dist; dist = FT_MulFix( dist, scale ); if ( dist < best_dist ) { best_dist = dist; best_blue = &blue->shoot; best_blue_is_neutral = is_neutral_blue; } } } } } if ( best_blue ) { edge->blue_edge = best_blue; if ( best_blue_is_neutral ) edge->flags |= AF_EDGE_NEUTRAL; } } } /* Initialize hinting engine. */ static FT_Error af_latin_hints_init( AF_GlyphHints hints, AF_StyleMetrics metrics_ ) /* AF_LatinMetrics */ { AF_LatinMetrics metrics = (AF_LatinMetrics)metrics_; FT_Render_Mode mode; FT_UInt32 scaler_flags, other_flags; FT_Face face = metrics->root.scaler.face; af_glyph_hints_rescale( hints, (AF_StyleMetrics)metrics ); /* * correct x_scale and y_scale if needed, since they may have * been modified by `af_latin_metrics_scale_dim' above */ hints->x_scale = metrics->axis[AF_DIMENSION_HORZ].scale; hints->x_delta = metrics->axis[AF_DIMENSION_HORZ].delta; hints->y_scale = metrics->axis[AF_DIMENSION_VERT].scale; hints->y_delta = metrics->axis[AF_DIMENSION_VERT].delta; /* compute flags depending on render mode, etc. */ mode = metrics->root.scaler.render_mode; scaler_flags = hints->scaler_flags; other_flags = 0; /* * We snap the width of vertical stems for the monochrome and * horizontal LCD rendering targets only. */ if ( mode == FT_RENDER_MODE_MONO || mode == FT_RENDER_MODE_LCD ) other_flags |= AF_LATIN_HINTS_HORZ_SNAP; /* * We snap the width of horizontal stems for the monochrome and * vertical LCD rendering targets only. */ if ( mode == FT_RENDER_MODE_MONO || mode == FT_RENDER_MODE_LCD_V ) other_flags |= AF_LATIN_HINTS_VERT_SNAP; /* * We adjust stems to full pixels unless in `light' or `lcd' mode. */ if ( mode != FT_RENDER_MODE_LIGHT && mode != FT_RENDER_MODE_LCD ) other_flags |= AF_LATIN_HINTS_STEM_ADJUST; if ( mode == FT_RENDER_MODE_MONO ) other_flags |= AF_LATIN_HINTS_MONO; /* * In `light' or `lcd' mode we disable horizontal hinting completely. * We also do it if the face is italic. * * However, if warping is enabled (which only works in `light' hinting * mode), advance widths get adjusted, too. */ if ( mode == FT_RENDER_MODE_LIGHT || mode == FT_RENDER_MODE_LCD || ( face->style_flags & FT_STYLE_FLAG_ITALIC ) != 0 ) scaler_flags |= AF_SCALER_FLAG_NO_HORIZONTAL; hints->scaler_flags = scaler_flags; hints->other_flags = other_flags; return FT_Err_Ok; } /*************************************************************************/ /*************************************************************************/ /***** *****/ /***** L A T I N G L Y P H G R I D - F I T T I N G *****/ /***** *****/ /*************************************************************************/ /*************************************************************************/ /* Snap a given width in scaled coordinates to one of the */ /* current standard widths. */ static FT_Pos af_latin_snap_width( AF_Width widths, FT_UInt count, FT_Pos width ) { FT_UInt n; FT_Pos best = 64 + 32 + 2; FT_Pos reference = width; FT_Pos scaled; for ( n = 0; n < count; n++ ) { FT_Pos w; FT_Pos dist; w = widths[n].cur; dist = width - w; if ( dist < 0 ) dist = -dist; if ( dist < best ) { best = dist; reference = w; } } scaled = FT_PIX_ROUND( reference ); if ( width >= reference ) { if ( width < scaled + 48 ) width = reference; } else { if ( width > scaled - 48 ) width = reference; } return width; } /* Compute the snapped width of a given stem, ignoring very thin ones. */ /* There is a lot of voodoo in this function; changing the hard-coded */ /* parameters influence the whole hinting process. */ static FT_Pos af_latin_compute_stem_width( AF_GlyphHints hints, AF_Dimension dim, FT_Pos width, FT_Pos base_delta, FT_UInt base_flags, FT_UInt stem_flags ) { AF_LatinMetrics metrics = (AF_LatinMetrics)hints->metrics; AF_LatinAxis axis = &metrics->axis[dim]; FT_Pos dist = width; FT_Int sign = 0; FT_Int vertical = ( dim == AF_DIMENSION_VERT ); if ( !AF_LATIN_HINTS_DO_STEM_ADJUST( hints ) || axis->extra_light ) return width; if ( dist < 0 ) { dist = -width; sign = 1; } if ( ( vertical && !AF_LATIN_HINTS_DO_VERT_SNAP( hints ) ) || ( !vertical && !AF_LATIN_HINTS_DO_HORZ_SNAP( hints ) ) ) { /* smooth hinting process: very lightly quantize the stem width */ /* leave the widths of serifs alone */ if ( ( stem_flags & AF_EDGE_SERIF ) && vertical && ( dist < 3 * 64 ) ) goto Done_Width; else if ( base_flags & AF_EDGE_ROUND ) { if ( dist < 80 ) dist = 64; } else if ( dist < 56 ) dist = 56; if ( axis->width_count > 0 ) { FT_Pos delta; /* compare to standard width */ delta = dist - axis->widths[0].cur; if ( delta < 0 ) delta = -delta; if ( delta < 40 ) { dist = axis->widths[0].cur; if ( dist < 48 ) dist = 48; goto Done_Width; } if ( dist < 3 * 64 ) { delta = dist & 63; dist &= -64; if ( delta < 10 ) dist += delta; else if ( delta < 32 ) dist += 10; else if ( delta < 54 ) dist += 54; else dist += delta; } else { /* A stem's end position depends on two values: the start */ /* position and the stem length. The former gets usually */ /* rounded to the grid, while the latter gets rounded also if it */ /* exceeds a certain length (see below in this function). This */ /* `double rounding' can lead to a great difference to the */ /* original, unhinted position; this normally doesn't matter for */ /* large PPEM values, but for small sizes it can easily make */ /* outlines collide. For this reason, we adjust the stem length */ /* by a small amount depending on the PPEM value in case the */ /* former and latter rounding both point into the same */ /* direction. */ FT_Pos bdelta = 0; if ( ( ( width > 0 ) && ( base_delta > 0 ) ) || ( ( width < 0 ) && ( base_delta < 0 ) ) ) { FT_UInt ppem = metrics->root.scaler.face->size->metrics.x_ppem; if ( ppem < 10 ) bdelta = base_delta; else if ( ppem < 30 ) bdelta = ( base_delta * (FT_Pos)( 30 - ppem ) ) / 20; if ( bdelta < 0 ) bdelta = -bdelta; } dist = ( dist - bdelta + 32 ) & ~63; } } } else { /* strong hinting process: snap the stem width to integer pixels */ FT_Pos org_dist = dist; dist = af_latin_snap_width( axis->widths, axis->width_count, dist ); if ( vertical ) { /* in the case of vertical hinting, always round */ /* the stem heights to integer pixels */ if ( dist >= 64 ) dist = ( dist + 16 ) & ~63; else dist = 64; } else { if ( AF_LATIN_HINTS_DO_MONO( hints ) ) { /* monochrome horizontal hinting: snap widths to integer pixels */ /* with a different threshold */ if ( dist < 64 ) dist = 64; else dist = ( dist + 32 ) & ~63; } else { /* for horizontal anti-aliased hinting, we adopt a more subtle */ /* approach: we strengthen small stems, round stems whose size */ /* is between 1 and 2 pixels to an integer, otherwise nothing */ if ( dist < 48 ) dist = ( dist + 64 ) >> 1; else if ( dist < 128 ) { /* We only round to an integer width if the corresponding */ /* distortion is less than 1/4 pixel. Otherwise this */ /* makes everything worse since the diagonals, which are */ /* not hinted, appear a lot bolder or thinner than the */ /* vertical stems. */ FT_Pos delta; dist = ( dist + 22 ) & ~63; delta = dist - org_dist; if ( delta < 0 ) delta = -delta; if ( delta >= 16 ) { dist = org_dist; if ( dist < 48 ) dist = ( dist + 64 ) >> 1; } } else /* round otherwise to prevent color fringes in LCD mode */ dist = ( dist + 32 ) & ~63; } } } Done_Width: if ( sign ) dist = -dist; return dist; } /* Align one stem edge relative to the previous stem edge. */ static void af_latin_align_linked_edge( AF_GlyphHints hints, AF_Dimension dim, AF_Edge base_edge, AF_Edge stem_edge ) { FT_Pos dist, base_delta; FT_Pos fitted_width; dist = stem_edge->opos - base_edge->opos; base_delta = base_edge->pos - base_edge->opos; fitted_width = af_latin_compute_stem_width( hints, dim, dist, base_delta, base_edge->flags, stem_edge->flags ); stem_edge->pos = base_edge->pos + fitted_width; FT_TRACE5(( " LINK: edge %td (opos=%.2f) linked to %.2f," " dist was %.2f, now %.2f\n", stem_edge - hints->axis[dim].edges, (double)stem_edge->opos / 64, (double)stem_edge->pos / 64, (double)dist / 64, (double)fitted_width / 64 )); } /* Shift the coordinates of the `serif' edge by the same amount */ /* as the corresponding `base' edge has been moved already. */ static void af_latin_align_serif_edge( AF_GlyphHints hints, AF_Edge base, AF_Edge serif ) { FT_UNUSED( hints ); serif->pos = base->pos + ( serif->opos - base->opos ); } /*************************************************************************/ /*************************************************************************/ /*************************************************************************/ /**** ****/ /**** E D G E H I N T I N G ****/ /**** ****/ /*************************************************************************/ /*************************************************************************/ /*************************************************************************/ /* The main grid-fitting routine. */ static void af_latin_hint_edges( AF_GlyphHints hints, AF_Dimension dim ) { AF_AxisHints axis = &hints->axis[dim]; AF_Edge edges = axis->edges; AF_Edge edge_limit = FT_OFFSET( edges, axis->num_edges ); FT_PtrDist n_edges; AF_Edge edge; AF_Edge anchor = NULL; FT_Int has_serifs = 0; AF_StyleClass style_class = hints->metrics->style_class; AF_ScriptClass script_class = af_script_classes[style_class->script]; FT_Bool top_to_bottom_hinting = 0; #ifdef FT_DEBUG_LEVEL_TRACE FT_UInt num_actions = 0; #endif FT_TRACE5(( "latin %s edge hinting (style `%s')\n", dim == AF_DIMENSION_VERT ? "horizontal" : "vertical", af_style_names[hints->metrics->style_class->style] )); if ( dim == AF_DIMENSION_VERT ) top_to_bottom_hinting = script_class->top_to_bottom_hinting; /* we begin by aligning all stems relative to the blue zone */ /* if needed -- that's only for horizontal edges */ if ( dim == AF_DIMENSION_VERT && AF_HINTS_DO_BLUES( hints ) ) { for ( edge = edges; edge < edge_limit; edge++ ) { AF_Width blue; AF_Edge edge1, edge2; /* these edges form the stem to check */ if ( edge->flags & AF_EDGE_DONE ) continue; edge1 = NULL; edge2 = edge->link; /* * If a stem contains both a neutral and a non-neutral blue zone, * skip the neutral one. Otherwise, outlines with different * directions might be incorrectly aligned at the same vertical * position. * * If we have two neutral blue zones, skip one of them. * */ if ( edge->blue_edge && edge2 && edge2->blue_edge ) { FT_Byte neutral = edge->flags & AF_EDGE_NEUTRAL; FT_Byte neutral2 = edge2->flags & AF_EDGE_NEUTRAL; if ( neutral2 ) { edge2->blue_edge = NULL; edge2->flags &= ~AF_EDGE_NEUTRAL; } else if ( neutral ) { edge->blue_edge = NULL; edge->flags &= ~AF_EDGE_NEUTRAL; } } blue = edge->blue_edge; if ( blue ) edge1 = edge; /* flip edges if the other edge is aligned to a blue zone */ else if ( edge2 && edge2->blue_edge ) { blue = edge2->blue_edge; edge1 = edge2; edge2 = edge; } if ( !edge1 ) continue; #ifdef FT_DEBUG_LEVEL_TRACE if ( !anchor ) FT_TRACE5(( " BLUE_ANCHOR: edge %td (opos=%.2f) snapped to %.2f," " was %.2f (anchor=edge %td)\n", edge1 - edges, (double)edge1->opos / 64, (double)blue->fit / 64, (double)edge1->pos / 64, edge - edges )); else FT_TRACE5(( " BLUE: edge %td (opos=%.2f) snapped to %.2f," " was %.2f\n", edge1 - edges, (double)edge1->opos / 64, (double)blue->fit / 64, (double)edge1->pos / 64 )); num_actions++; #endif edge1->pos = blue->fit; edge1->flags |= AF_EDGE_DONE; if ( edge2 && !edge2->blue_edge ) { af_latin_align_linked_edge( hints, dim, edge1, edge2 ); edge2->flags |= AF_EDGE_DONE; #ifdef FT_DEBUG_LEVEL_TRACE num_actions++; #endif } if ( !anchor ) anchor = edge; } } /* now we align all other stem edges, trying to maintain the */ /* relative order of stems in the glyph */ for ( edge = edges; edge < edge_limit; edge++ ) { AF_Edge edge2; if ( edge->flags & AF_EDGE_DONE ) continue; /* skip all non-stem edges */ edge2 = edge->link; if ( !edge2 ) { has_serifs++; continue; } /* now align the stem */ /* this should not happen, but it's better to be safe */ if ( edge2->blue_edge ) { FT_TRACE5(( " ASSERTION FAILED for edge %td\n", edge2 - edges )); af_latin_align_linked_edge( hints, dim, edge2, edge ); edge->flags |= AF_EDGE_DONE; #ifdef FT_DEBUG_LEVEL_TRACE num_actions++; #endif continue; } if ( !anchor ) { /* if we reach this if clause, no stem has been aligned yet */ FT_Pos org_len, org_center, cur_len; FT_Pos cur_pos1, error1, error2, u_off, d_off; org_len = edge2->opos - edge->opos; cur_len = af_latin_compute_stem_width( hints, dim, org_len, 0, edge->flags, edge2->flags ); /* some voodoo to specially round edges for small stem widths; */ /* the idea is to align the center of a stem, then shifting */ /* the stem edges to suitable positions */ if ( cur_len <= 64 ) { /* width <= 1px */ u_off = 32; d_off = 32; } else { /* 1px < width < 1.5px */ u_off = 38; d_off = 26; } if ( cur_len < 96 ) { org_center = edge->opos + ( org_len >> 1 ); cur_pos1 = FT_PIX_ROUND( org_center ); error1 = org_center - ( cur_pos1 - u_off ); if ( error1 < 0 ) error1 = -error1; error2 = org_center - ( cur_pos1 + d_off ); if ( error2 < 0 ) error2 = -error2; if ( error1 < error2 ) cur_pos1 -= u_off; else cur_pos1 += d_off; edge->pos = cur_pos1 - cur_len / 2; edge2->pos = edge->pos + cur_len; } else edge->pos = FT_PIX_ROUND( edge->opos ); anchor = edge; edge->flags |= AF_EDGE_DONE; FT_TRACE5(( " ANCHOR: edge %td (opos=%.2f) and %td (opos=%.2f)" " snapped to %.2f and %.2f\n", edge - edges, (double)edge->opos / 64, edge2 - edges, (double)edge2->opos / 64, (double)edge->pos / 64, (double)edge2->pos / 64 )); af_latin_align_linked_edge( hints, dim, edge, edge2 ); #ifdef FT_DEBUG_LEVEL_TRACE num_actions += 2; #endif } else { FT_Pos org_pos, org_len, org_center, cur_len; FT_Pos cur_pos1, cur_pos2, delta1, delta2; org_pos = anchor->pos + ( edge->opos - anchor->opos ); org_len = edge2->opos - edge->opos; org_center = org_pos + ( org_len >> 1 ); cur_len = af_latin_compute_stem_width( hints, dim, org_len, 0, edge->flags, edge2->flags ); if ( edge2->flags & AF_EDGE_DONE ) { FT_TRACE5(( " ADJUST: edge %td (pos=%.2f) moved to %.2f\n", edge - edges, (double)edge->pos / 64, (double)( edge2->pos - cur_len ) / 64 )); edge->pos = edge2->pos - cur_len; } else if ( cur_len < 96 ) { FT_Pos u_off, d_off; cur_pos1 = FT_PIX_ROUND( org_center ); if ( cur_len <= 64 ) { u_off = 32; d_off = 32; } else { u_off = 38; d_off = 26; } delta1 = org_center - ( cur_pos1 - u_off ); if ( delta1 < 0 ) delta1 = -delta1; delta2 = org_center - ( cur_pos1 + d_off ); if ( delta2 < 0 ) delta2 = -delta2; if ( delta1 < delta2 ) cur_pos1 -= u_off; else cur_pos1 += d_off; edge->pos = cur_pos1 - cur_len / 2; edge2->pos = cur_pos1 + cur_len / 2; FT_TRACE5(( " STEM: edge %td (opos=%.2f) linked to %td (opos=%.2f)" " snapped to %.2f and %.2f\n", edge - edges, (double)edge->opos / 64, edge2 - edges, (double)edge2->opos / 64, (double)edge->pos / 64, (double)edge2->pos / 64 )); } else { org_pos = anchor->pos + ( edge->opos - anchor->opos ); org_len = edge2->opos - edge->opos; org_center = org_pos + ( org_len >> 1 ); cur_len = af_latin_compute_stem_width( hints, dim, org_len, 0, edge->flags, edge2->flags ); cur_pos1 = FT_PIX_ROUND( org_pos ); delta1 = cur_pos1 + ( cur_len >> 1 ) - org_center; if ( delta1 < 0 ) delta1 = -delta1; cur_pos2 = FT_PIX_ROUND( org_pos + org_len ) - cur_len; delta2 = cur_pos2 + ( cur_len >> 1 ) - org_center; if ( delta2 < 0 ) delta2 = -delta2; edge->pos = ( delta1 < delta2 ) ? cur_pos1 : cur_pos2; edge2->pos = edge->pos + cur_len; FT_TRACE5(( " STEM: edge %td (opos=%.2f) linked to %td (opos=%.2f)" " snapped to %.2f and %.2f\n", edge - edges, (double)edge->opos / 64, edge2 - edges, (double)edge2->opos / 64, (double)edge->pos / 64, (double)edge2->pos / 64 )); } #ifdef FT_DEBUG_LEVEL_TRACE num_actions++; #endif edge->flags |= AF_EDGE_DONE; edge2->flags |= AF_EDGE_DONE; if ( edge > edges && ( top_to_bottom_hinting ? ( edge->pos > edge[-1].pos ) : ( edge->pos < edge[-1].pos ) ) ) { /* don't move if stem would (almost) disappear otherwise; */ /* the ad-hoc value 16 corresponds to 1/4px */ if ( edge->link && FT_ABS( edge->link->pos - edge[-1].pos ) > 16 ) { #ifdef FT_DEBUG_LEVEL_TRACE FT_TRACE5(( " BOUND: edge %td (pos=%.2f) moved to %.2f\n", edge - edges, (double)edge->pos / 64, (double)edge[-1].pos / 64 )); num_actions++; #endif edge->pos = edge[-1].pos; } } } } /* make sure that lowercase m's maintain their symmetry */ /* In general, lowercase m's have six vertical edges if they are sans */ /* serif, or twelve if they are with serifs. This implementation is */ /* based on that assumption, and seems to work very well with most */ /* faces. However, if for a certain face this assumption is not */ /* true, the m is just rendered like before. In addition, any stem */ /* correction will only be applied to symmetrical glyphs (even if the */ /* glyph is not an m), so the potential for unwanted distortion is */ /* relatively low. */ /* We don't handle horizontal edges since we can't easily assure that */ /* the third (lowest) stem aligns with the base line; it might end up */ /* one pixel higher or lower. */ n_edges = edge_limit - edges; if ( dim == AF_DIMENSION_HORZ && ( n_edges == 6 || n_edges == 12 ) ) { AF_Edge edge1, edge2, edge3; FT_Pos dist1, dist2, span, delta; if ( n_edges == 6 ) { edge1 = edges; edge2 = edges + 2; edge3 = edges + 4; } else { edge1 = edges + 1; edge2 = edges + 5; edge3 = edges + 9; } dist1 = edge2->opos - edge1->opos; dist2 = edge3->opos - edge2->opos; span = dist1 - dist2; if ( span < 0 ) span = -span; if ( span < 8 ) { delta = edge3->pos - ( 2 * edge2->pos - edge1->pos ); edge3->pos -= delta; if ( edge3->link ) edge3->link->pos -= delta; /* move the serifs along with the stem */ if ( n_edges == 12 ) { ( edges + 8 )->pos -= delta; ( edges + 11 )->pos -= delta; } edge3->flags |= AF_EDGE_DONE; if ( edge3->link ) edge3->link->flags |= AF_EDGE_DONE; } } if ( has_serifs || !anchor ) { /* * now hint the remaining edges (serifs and single) in order * to complete our processing */ for ( edge = edges; edge < edge_limit; edge++ ) { FT_Pos delta; if ( edge->flags & AF_EDGE_DONE ) continue; delta = 1000; if ( edge->serif ) { delta = edge->serif->opos - edge->opos; if ( delta < 0 ) delta = -delta; } if ( delta < 64 + 16 ) { af_latin_align_serif_edge( hints, edge->serif, edge ); FT_TRACE5(( " SERIF: edge %td (opos=%.2f) serif to %td (opos=%.2f)" " aligned to %.2f\n", edge - edges, (double)edge->opos / 64, edge->serif - edges, (double)edge->serif->opos / 64, (double)edge->pos / 64 )); } else if ( !anchor ) { edge->pos = FT_PIX_ROUND( edge->opos ); anchor = edge; FT_TRACE5(( " SERIF_ANCHOR: edge %td (opos=%.2f)" " snapped to %.2f\n", edge - edges, (double)edge->opos / 64, (double)edge->pos / 64 )); } else { AF_Edge before, after; for ( before = edge - 1; before >= edges; before-- ) if ( before->flags & AF_EDGE_DONE ) break; for ( after = edge + 1; after < edge_limit; after++ ) if ( after->flags & AF_EDGE_DONE ) break; if ( before >= edges && before < edge && after < edge_limit && after > edge ) { if ( after->opos == before->opos ) edge->pos = before->pos; else edge->pos = before->pos + FT_MulDiv( edge->opos - before->opos, after->pos - before->pos, after->opos - before->opos ); FT_TRACE5(( " SERIF_LINK1: edge %td (opos=%.2f) snapped to %.2f" " from %td (opos=%.2f)\n", edge - edges, (double)edge->opos / 64, (double)edge->pos / 64, before - edges, (double)before->opos / 64 )); } else { edge->pos = anchor->pos + ( ( edge->opos - anchor->opos + 16 ) & ~31 ); FT_TRACE5(( " SERIF_LINK2: edge %td (opos=%.2f)" " snapped to %.2f\n", edge - edges, (double)edge->opos / 64, (double)edge->pos / 64 )); } } #ifdef FT_DEBUG_LEVEL_TRACE num_actions++; #endif edge->flags |= AF_EDGE_DONE; if ( edge > edges && ( top_to_bottom_hinting ? ( edge->pos > edge[-1].pos ) : ( edge->pos < edge[-1].pos ) ) ) { /* don't move if stem would (almost) disappear otherwise; */ /* the ad-hoc value 16 corresponds to 1/4px */ if ( edge->link && FT_ABS( edge->link->pos - edge[-1].pos ) > 16 ) { #ifdef FT_DEBUG_LEVEL_TRACE FT_TRACE5(( " BOUND: edge %td (pos=%.2f) moved to %.2f\n", edge - edges, (double)edge->pos / 64, (double)edge[-1].pos / 64 )); num_actions++; #endif edge->pos = edge[-1].pos; } } if ( edge + 1 < edge_limit && edge[1].flags & AF_EDGE_DONE && ( top_to_bottom_hinting ? ( edge->pos < edge[1].pos ) : ( edge->pos > edge[1].pos ) ) ) { /* don't move if stem would (almost) disappear otherwise; */ /* the ad-hoc value 16 corresponds to 1/4px */ if ( edge->link && FT_ABS( edge->link->pos - edge[-1].pos ) > 16 ) { #ifdef FT_DEBUG_LEVEL_TRACE FT_TRACE5(( " BOUND: edge %td (pos=%.2f) moved to %.2f\n", edge - edges, (double)edge->pos / 64, (double)edge[1].pos / 64 )); num_actions++; #endif edge->pos = edge[1].pos; } } } } #ifdef FT_DEBUG_LEVEL_TRACE if ( !num_actions ) FT_TRACE5(( " (none)\n" )); FT_TRACE5(( "\n" )); #endif } /* Apply the complete hinting algorithm to a latin glyph. */ static FT_Error af_latin_hints_apply( FT_UInt glyph_index, AF_GlyphHints hints, FT_Outline* outline, AF_StyleMetrics metrics_ ) /* AF_LatinMetrics */ { AF_LatinMetrics metrics = (AF_LatinMetrics)metrics_; FT_Error error; int dim; AF_LatinAxis axis; error = af_glyph_hints_reload( hints, outline ); if ( error ) goto Exit; /* analyze glyph outline */ if ( AF_HINTS_DO_HORIZONTAL( hints ) ) { axis = &metrics->axis[AF_DIMENSION_HORZ]; error = af_latin_hints_detect_features( hints, axis->width_count, axis->widths, AF_DIMENSION_HORZ ); if ( error ) goto Exit; } if ( AF_HINTS_DO_VERTICAL( hints ) ) { axis = &metrics->axis[AF_DIMENSION_VERT]; error = af_latin_hints_detect_features( hints, axis->width_count, axis->widths, AF_DIMENSION_VERT ); if ( error ) goto Exit; /* apply blue zones to base characters only */ if ( !( metrics->root.globals->glyph_styles[glyph_index] & AF_NONBASE ) ) af_latin_hints_compute_blue_edges( hints, metrics ); } /* grid-fit the outline */ for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ ) { if ( ( dim == AF_DIMENSION_HORZ && AF_HINTS_DO_HORIZONTAL( hints ) ) || ( dim == AF_DIMENSION_VERT && AF_HINTS_DO_VERTICAL( hints ) ) ) { af_latin_hint_edges( hints, (AF_Dimension)dim ); af_glyph_hints_align_edge_points( hints, (AF_Dimension)dim ); af_glyph_hints_align_strong_points( hints, (AF_Dimension)dim ); af_glyph_hints_align_weak_points( hints, (AF_Dimension)dim ); } } af_glyph_hints_save( hints, outline ); Exit: return error; } /*************************************************************************/ /*************************************************************************/ /***** *****/ /***** L A T I N S C R I P T C L A S S *****/ /***** *****/ /*************************************************************************/ /*************************************************************************/ AF_DEFINE_WRITING_SYSTEM_CLASS( af_latin_writing_system_class, AF_WRITING_SYSTEM_LATIN, sizeof ( AF_LatinMetricsRec ), (AF_WritingSystem_InitMetricsFunc) af_latin_metrics_init, /* style_metrics_init */ (AF_WritingSystem_ScaleMetricsFunc)af_latin_metrics_scale, /* style_metrics_scale */ (AF_WritingSystem_DoneMetricsFunc) NULL, /* style_metrics_done */ (AF_WritingSystem_GetStdWidthsFunc)af_latin_get_standard_widths, /* style_metrics_getstdw */ (AF_WritingSystem_InitHintsFunc) af_latin_hints_init, /* style_hints_init */ (AF_WritingSystem_ApplyHintsFunc) af_latin_hints_apply /* style_hints_apply */ ) /* END */