ref: 6be99f9104c458eeda48a51adeb65ce20ade45c3
dir: /src/autofit/aflatin.c/
/***************************************************************************/ /* */ /* aflatin.c */ /* */ /* Auto-fitter hinting routines for latin script (body). */ /* */ /* Copyright 2003, 2004, 2005, 2006 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 "aflatin.h" #include "aferrors.h" #ifdef AF_USE_WARPER #include "afwarp.h" #endif /*************************************************************************/ /*************************************************************************/ /***** *****/ /***** L A T I N G L O B A L M E T R I C S *****/ /***** *****/ /*************************************************************************/ /*************************************************************************/ static void af_latin_metrics_init_widths( AF_LatinMetrics metrics, FT_Face face ) { /* scan the array of segments in each direction */ AF_GlyphHintsRec hints[1]; af_glyph_hints_init( hints, face->memory ); metrics->axis[AF_DIMENSION_HORZ].width_count = 0; metrics->axis[AF_DIMENSION_VERT].width_count = 0; /* For now, compute the standard width and height from the `o'. */ { FT_Error error; FT_UInt glyph_index; int dim; AF_ScriptMetricsRec dummy[1]; AF_Scaler scaler = &dummy->scaler; glyph_index = FT_Get_Char_Index( face, 'o' ); if ( glyph_index == 0 ) goto Exit; error = FT_Load_Glyph( face, glyph_index, FT_LOAD_NO_SCALE ); if ( error || face->glyph->outline.n_points <= 0 ) goto Exit; FT_ZERO( dummy ); scaler->x_scale = scaler->y_scale = 0x10000L; scaler->x_delta = scaler->y_delta = 0; scaler->face = face; scaler->render_mode = FT_RENDER_MODE_NORMAL; scaler->flags = 0; af_glyph_hints_rescale( hints, 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; FT_Pos edge_distance_threshold = 32000; error = af_latin_hints_compute_segments( hints, (AF_Dimension)dim ); if ( error ) goto Exit; af_latin_hints_link_segments( hints, (AF_Dimension)dim ); seg = axhints->segments; limit = 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; } } af_sort_widths( num_widths, axis->widths ); axis->width_count = num_widths; /* we will now try to find the smallest width */ if ( num_widths > 0 && axis->widths[0].org < edge_distance_threshold ) edge_distance_threshold = axis->widths[0].org; /* Now, compute the edge distance threshold as a fraction of the */ /* smallest width in the font. Set it in `hinter->glyph' too! */ if ( edge_distance_threshold == 32000 ) edge_distance_threshold = 50; /* let's try 20% */ axis->edge_distance_threshold = edge_distance_threshold / 5; } } Exit: af_glyph_hints_done( hints ); } #define AF_LATIN_MAX_TEST_CHARACTERS 12 static const char* const af_latin_blue_chars[AF_LATIN_MAX_BLUES] = { "THEZOCQS", "HEZLOCUS", "fijkdbh", "xzroesc", "xzroesc", "pqgjy" }; static void af_latin_metrics_init_blues( AF_LatinMetrics metrics, FT_Face face ) { FT_Pos flats [AF_LATIN_MAX_TEST_CHARACTERS]; FT_Pos rounds[AF_LATIN_MAX_TEST_CHARACTERS]; FT_Int num_flats; FT_Int num_rounds; FT_Int bb; AF_LatinBlue blue; FT_Error error; AF_LatinAxis axis = &metrics->axis[AF_DIMENSION_VERT]; FT_GlyphSlot glyph = face->glyph; /* we compute the blues simply by loading each character from the */ /* 'af_latin_blue_chars[blues]' string, then compute its top-most or */ /* bottom-most points (depending on `AF_IS_TOP_BLUE') */ AF_LOG(( "blue zones computation\n" )); AF_LOG(( "------------------------------------------------\n" )); for ( bb = 0; bb < AF_LATIN_BLUE_MAX; bb++ ) { const char* p = af_latin_blue_chars[bb]; const char* limit = p + AF_LATIN_MAX_TEST_CHARACTERS; FT_Pos* blue_ref; FT_Pos* blue_shoot; AF_LOG(( "blue %3d: ", bb )); num_flats = 0; num_rounds = 0; for ( ; p < limit && *p; p++ ) { FT_UInt glyph_index; FT_Vector* extremum; FT_Vector* points; FT_Vector* point_limit; FT_Vector* point; FT_Bool round; AF_LOG(( "'%c'", *p )); /* load the character in the face -- skip unknown or empty ones */ glyph_index = FT_Get_Char_Index( face, (FT_UInt)*p ); if ( glyph_index == 0 ) continue; error = FT_Load_Glyph( face, glyph_index, FT_LOAD_NO_SCALE ); if ( error || glyph->outline.n_points <= 0 ) continue; /* now compute min or max point indices and coordinates */ points = glyph->outline.points; point_limit = points + glyph->outline.n_points; point = points; extremum = point; point++; if ( AF_LATIN_IS_TOP_BLUE( bb ) ) { for ( ; point < point_limit; point++ ) if ( point->y > extremum->y ) extremum = point; } else { for ( ; point < point_limit; point++ ) if ( point->y < extremum->y ) extremum = point; } AF_LOG(( "%5d", (int)extremum->y )); /* now, check whether the point belongs to a straight or round */ /* segment; we first need to find in which contour the extremum */ /* lies, then see its previous and next points */ { FT_Int idx = (FT_Int)( extremum - points ); FT_Int n; FT_Int first, last, prev, next, end; FT_Pos dist; last = -1; first = 0; for ( n = 0; n < glyph->outline.n_contours; n++ ) { end = glyph->outline.contours[n]; if ( end >= idx ) { last = end; break; } first = end + 1; } /* XXX: should never happen! */ if ( last < 0 ) continue; /* now look for the previous and next points that are not on the */ /* same Y coordinate. Threshold the `closeness'... */ prev = idx; next = prev; do { if ( prev > first ) prev--; else prev = last; dist = points[prev].y - extremum->y; if ( dist < -5 || dist > 5 ) break; } while ( prev != idx ); do { if ( next < last ) next++; else next = first; dist = points[next].y - extremum->y; if ( dist < -5 || dist > 5 ) break; } while ( next != idx ); /* now, set the `round' flag depending on the segment's kind */ round = FT_BOOL( FT_CURVE_TAG( glyph->outline.tags[prev] ) != FT_CURVE_TAG_ON || FT_CURVE_TAG( glyph->outline.tags[next] ) != FT_CURVE_TAG_ON ); AF_LOG(( "%c ", round ? 'r' : 'f' )); } if ( round ) rounds[num_rounds++] = extremum->y; else flats[num_flats++] = extremum->y; } AF_LOG(( "\n" )); 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 */ AF_LOG(( "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( bb ) ^ over_ref ) *blue_shoot = *blue_ref = ( shoot + ref ) / 2; } blue->flags = 0; if ( AF_LATIN_IS_TOP_BLUE( bb ) ) blue->flags |= AF_LATIN_BLUE_TOP; /* * The following flags 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 ( bb == AF_LATIN_BLUE_SMALL_TOP ) blue->flags |= AF_LATIN_BLUE_ADJUSTMENT; AF_LOG(( "-- ref = %ld, shoot = %ld\n", *blue_ref, *blue_shoot )); } return; } FT_LOCAL_DEF( FT_Error ) af_latin_metrics_init( AF_LatinMetrics metrics, FT_Face face ) { FT_Error error = AF_Err_Ok; FT_CharMap oldmap = face->charmap; FT_UInt ee; static const FT_Encoding latin_encodings[] = { FT_ENCODING_UNICODE, FT_ENCODING_APPLE_ROMAN, FT_ENCODING_ADOBE_STANDARD, FT_ENCODING_ADOBE_LATIN_1, FT_ENCODING_NONE /* end of list */ }; metrics->units_per_em = face->units_per_EM; /* do we have a latin charmap in there? */ for ( ee = 0; latin_encodings[ee] != FT_ENCODING_NONE; ee++ ) { error = FT_Select_Charmap( face, latin_encodings[ee] ); if ( !error ) break; } if ( !error ) { af_latin_metrics_init_widths( metrics, face ); af_latin_metrics_init_blues( metrics, face ); } FT_Set_Charmap( face, oldmap ); return AF_Err_Ok; } 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_MulFix( blue->shoot.org, scaler->y_scale ); FT_Pos fitted = FT_PIX_ROUND( scaled ); if ( scaled != fitted ) { if ( dim == AF_DIMENSION_HORZ ) { if ( fitted < scaled ) scale -= scale/50; /* x_scale = x_scale*0.98 */ } else { scale = FT_MulDiv( scale, fitted, scaled ); } } } } 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; } /* scale the standard 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; } if ( dim == AF_DIMENSION_VERT ) { /* 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 ) { FT_Pos delta1, delta2; 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; blue->flags |= AF_LATIN_BLUE_ACTIVE; } } } } FT_LOCAL_DEF( void ) af_latin_metrics_scale( AF_LatinMetrics metrics, AF_Scaler scaler ) { metrics->root.scaler.render_mode = scaler->render_mode; af_latin_metrics_scale_dim( metrics, scaler, AF_DIMENSION_HORZ ); af_latin_metrics_scale_dim( metrics, scaler, AF_DIMENSION_VERT ); } /*************************************************************************/ /*************************************************************************/ /***** *****/ /***** L A T I N G L Y P H A N A L Y S I S *****/ /***** *****/ /*************************************************************************/ /*************************************************************************/ FT_LOCAL_DEF( FT_Error ) af_latin_hints_compute_segments( AF_GlyphHints hints, AF_Dimension dim ) { AF_AxisHints axis = &hints->axis[dim]; FT_Memory memory = hints->memory; FT_Error error = AF_Err_Ok; AF_Segment segment = NULL; AF_Point* contour = hints->contours; AF_Point* contour_limit = contour + hints->num_contours; AF_Direction major_dir, segment_dir; #ifdef AF_HINT_METRICS AF_Point min_point = 0; AF_Point max_point = 0; FT_Pos min_coord = 32000; FT_Pos max_coord = -32000; #endif 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; FT_Pos min_pos = 32000; /* minimum segment pos != min_coord */ FT_Pos max_pos = -32000; /* maximum segment pos != max_coord */ FT_Bool passed; #ifdef AF_HINT_METRICS if ( point->u < min_coord ) { min_coord = point->u; min_point = point; } if ( point->u > max_coord ) { max_coord = point->u; max_point = point; } #endif if ( point == last ) /* skip singletons -- just in case */ continue; 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 ) { u = point->u; if ( u < min_pos ) min_pos = u; if ( u > max_pos ) max_pos = u; if ( point->out_dir != segment_dir || point == last ) { /* we are just leaving an edge; record a new segment! */ segment->last = point; segment->pos = (FT_Short)( ( min_pos + max_pos ) >> 1 ); /* a segment is round if either its first or last point */ /* is a control point */ if ( ( segment->first->flags | point->flags ) & AF_FLAG_CONTROL ) segment->flags |= AF_EDGE_ROUND; /* compute segment size */ min_pos = max_pos = point->v; v = segment->first->v; if ( v < min_pos ) min_pos = v; if ( v > max_pos ) max_pos = v; segment->min_coord = (FT_Short)min_pos; segment->max_coord = (FT_Short)max_pos; on_edge = 0; segment = NULL; /* fallthrough */ } } /* now exit if we are at the start/end point */ if ( point == last ) { if ( passed ) break; passed = 1; } if ( !on_edge && FT_ABS( point->out_dir ) == major_dir ) { /* this is the start of a new segment! */ segment_dir = (AF_Direction)point->out_dir; /* clear all segment fields */ error = af_axis_hints_new_segment( axis, memory, &segment ); if ( error ) goto Exit; segment->dir = (FT_Char)segment_dir; segment->flags = AF_EDGE_NORMAL; min_pos = max_pos = point->u; segment->first = point; segment->last = point; segment->contour = contour; segment->score = 32000; segment->link = NULL; on_edge = 1; #ifdef AF_HINT_METRICS if ( point == max_point ) max_point = 0; if ( point == min_point ) min_point = 0; #endif } point = point->next; } } /* contours */ #ifdef AF_HINT_METRICS /* we need to ensure that there are edges on the left-most and */ /* right-most points of the glyph in order to hint the metrics; */ /* we do this by inserting fake segments when needed */ if ( dim == AF_DIMENSION_HORZ ) { AF_Point point = hints->points; AF_Point point_limit = point + hints->num_points; FT_Pos min_pos = 32000; FT_Pos max_pos = -32000; min_point = 0; max_point = 0; /* compute minimum and maximum points */ for ( ; point < point_limit; point++ ) { FT_Pos x = point->fx; if ( x < min_pos ) { min_pos = x; min_point = point; } if ( x > max_pos ) { max_pos = x; max_point = point; } } /* insert minimum segment */ if ( min_point ) { /* clear all segment fields */ error = af_axis_hints_new_segment( axis, memory, &segment ); if ( error ) goto Exit; segment->dir = segment_dir; segment->flags = AF_EDGE_NORMAL; segment->first = min_point; segment->last = min_point; segment->pos = min_pos; segment->score = 32000; segment->link = NULL; segment = NULL; } /* insert maximum segment */ if ( max_point ) { /* clear all segment fields */ error = af_axis_hints_new_segment( axis, memory, &segment ); if ( error ) goto Exit; segment->dir = segment_dir; segment->flags = AF_EDGE_NORMAL; segment->first = max_point; segment->last = max_point; segment->pos = max_pos; segment->score = 32000; segment->link = NULL; segment = NULL; } } #endif /* AF_HINT_METRICS */ Exit: return error; } FT_LOCAL_DEF( void ) af_latin_hints_link_segments( AF_GlyphHints hints, AF_Dimension dim ) { AF_AxisHints axis = &hints->axis[dim]; AF_Segment segments = axis->segments; AF_Segment segment_limit = segments + axis->num_segments; AF_Direction major_dir = axis->major_dir; AF_Segment seg1, seg2; /* now compare each segment to the others */ for ( seg1 = segments; seg1 < segment_limit; seg1++ ) { /* the fake segments are introduced to hint the metrics -- */ /* we must never link them to anything */ if ( seg1->first == seg1->last || seg1->dir != major_dir ) continue; for ( seg2 = segments; seg2 < segment_limit; seg2++ ) if ( seg2 != seg1 && seg1->dir + seg2->dir == 0 ) { FT_Pos pos1 = seg1->pos; FT_Pos pos2 = seg2->pos; FT_Pos dist = pos2 - pos1; if ( dist < 0 ) continue; { FT_Pos min = seg1->min_coord; FT_Pos max = seg1->max_coord; FT_Pos len, score; if ( min < seg2->min_coord ) min = seg2->min_coord; if ( max > seg2->max_coord ) max = seg2->max_coord; len = max - min; if ( len >= 8 ) { score = dist + 3000 / len; 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 */ for ( seg1 = segments; seg1 < segment_limit; seg1++ ) { seg2 = seg1->link; if ( seg2 ) { seg2->num_linked++; if ( seg2->link != seg1 ) { seg1->link = 0; seg1->serif = seg2->link; } } } } 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 = AF_Err_Ok; FT_Memory memory = hints->memory; AF_LatinAxis laxis = &((AF_LatinMetrics)hints->metrics)->axis[dim]; AF_Segment segments = axis->segments; AF_Segment segment_limit = segments + axis->num_segments; AF_Segment seg; AF_Direction up_dir; FT_Fixed scale; FT_Pos edge_distance_threshold; axis->num_edges = 0; scale = ( dim == AF_DIMENSION_HORZ ) ? hints->x_scale : hints->y_scale; up_dir = ( dim == AF_DIMENSION_HORZ ) ? AF_DIR_UP : AF_DIR_RIGHT; /*********************************************************************/ /* */ /* We will 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 will be processed in the second step to compute the */ /* edge's properties. */ /* */ /* Note that the edges table is sorted along the segment/edge */ /* position. */ /* */ /*********************************************************************/ 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 = 0; FT_Int ee; /* 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; } } 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, 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->fpos = seg->pos; edge->opos = edge->pos = FT_MulFix( seg->pos, scale ); 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; } } /*********************************************************************/ /* */ /* Good, we will now compute each edge's properties according to */ /* segments found on its position. Basically, these are: */ /* */ /* - 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 = 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? */ FT_Pos ups = 0; /* number of upwards segments */ FT_Pos downs = 0; /* number of downwards segments */ seg = edge->first; do { FT_Bool is_serif; /* check for roundness of segment */ if ( seg->flags & AF_EDGE_ROUND ) is_round++; else is_straight++; /* check for segment direction */ if ( seg->dir == up_dir ) ups += seg->max_coord-seg->min_coord; else downs += seg->max_coord-seg->min_coord; /* check for links -- if seg->serif is set, then seg->link must */ /* be ignored */ is_serif = (FT_Bool)( seg->serif && seg->serif->edge != edge ); if ( seg->link || 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; /* 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! */ /* gets 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 = 0; } } Exit: return error; } FT_LOCAL_DEF( FT_Error ) af_latin_hints_detect_features( AF_GlyphHints hints, AF_Dimension dim ) { FT_Error error; error = af_latin_hints_compute_segments( hints, dim ); if ( !error ) { af_latin_hints_link_segments( hints, dim ); error = af_latin_hints_compute_edges( hints, dim ); } return error; } FT_LOCAL_DEF( 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 = 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_Int bb; AF_Width best_blue = NULL; FT_Pos best_dist; /* initial threshold */ /* compute the initial threshold as a fraction of the EM size */ best_dist = FT_MulFix( metrics->units_per_em / 40, scale ); if ( best_dist > 64 / 2 ) best_dist = 64 / 2; for ( bb = 0; bb < AF_LATIN_BLUE_MAX; bb++ ) { AF_LatinBlue blue = latin->blues + bb; FT_Bool is_top_blue, is_major_dir; /* skip inactive blue zones (i.e., those that are too small) */ if ( !( blue->flags & AF_LATIN_BLUE_ACTIVE ) ) continue; /* if it is a top zone, check for right edges -- if it is a bottom */ /* zone, check for left edges */ /* */ /* of course, that's for TrueType */ is_top_blue = (FT_Byte)( ( blue->flags & AF_LATIN_BLUE_TOP ) != 0 ); is_major_dir = FT_BOOL( edge->dir == axis->major_dir ); /* if it is a top zone, the edge must be against the major */ /* direction; if it is a bottom zone, it must be in the major */ /* direction */ if ( is_top_blue ^ is_major_dir ) { 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; } /* now, compare it to the overshoot position if the edge is */ /* rounded, and if the edge is over the reference position of a */ /* top zone, or under the reference position of a bottom zone */ if ( edge->flags & AF_EDGE_ROUND && dist != 0 ) { FT_Bool is_under_ref = FT_BOOL( edge->fpos < blue->ref.org ); if ( is_top_blue ^ is_under_ref ) { blue = latin->blues + bb; 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; } } } } } if ( best_blue ) edge->blue_edge = best_blue; } } static FT_Error af_latin_hints_init( AF_GlyphHints hints, AF_LatinMetrics metrics ) { FT_Render_Mode mode; FT_UInt32 scaler_flags, other_flags; af_glyph_hints_rescale( hints, (AF_ScriptMetrics)metrics ); /* * correct x_scale and y_scale when needed, since they may have * been modified af_latin_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; #ifdef AF_USE_WARPER if ( mode == FT_RENDER_MODE_LCD || mode == FT_RENDER_MODE_LCD_V ) { metrics->root.scaler.render_mode = mode = FT_RENDER_MODE_NORMAL; } #endif 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 only if we don't use the `light' mode. */ if ( mode != FT_RENDER_MODE_LIGHT ) other_flags |= AF_LATIN_HINTS_STEM_ADJUST; if ( mode == FT_RENDER_MODE_MONO ) other_flags |= AF_LATIN_HINTS_MONO; /* * In `light' hinting mode we disable horizontal hinting completely. */ if ( mode == FT_RENDER_MODE_LIGHT ) scaler_flags |= AF_SCALER_FLAG_NO_HORIZONTAL; hints->scaler_flags = scaler_flags; hints->other_flags = other_flags; return 0; } /*************************************************************************/ /*************************************************************************/ /***** *****/ /***** 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_Int count, FT_Pos width ) { int 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 */ static FT_Pos af_latin_compute_stem_width( AF_GlyphHints hints, AF_Dimension dim, FT_Pos width, AF_Edge_Flags base_flags, AF_Edge_Flags 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 ) ) 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 */ if ( axis->width_count > 0 ) { 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 dist = ( dist + 32 ) & ~63; } } else { /* strong hinting process: snap the stem width to integer pixels */ 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 ) dist = ( dist + 22 ) & ~63; 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 = stem_edge->opos - base_edge->opos; FT_Pos fitted_width = af_latin_compute_stem_width( hints, dim, dist, (AF_Edge_Flags)base_edge->flags, (AF_Edge_Flags)stem_edge->flags ); stem_edge->pos = base_edge->pos + fitted_width; } 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 ****/ /**** ****/ /*************************************************************************/ /*************************************************************************/ /*************************************************************************/ FT_LOCAL_DEF( 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 = edges + axis->num_edges; FT_Int n_edges; AF_Edge edge; AF_Edge anchor = 0; FT_Int has_serifs = 0; /* we begin by aligning all stems relative to the blue zone */ /* if needed -- that's only for horizontal edges */ if ( dim == AF_DIMENSION_VERT ) { for ( edge = edges; edge < edge_limit; edge++ ) { AF_Width blue; AF_Edge edge1, edge2; if ( edge->flags & AF_EDGE_DONE ) continue; blue = edge->blue_edge; edge1 = NULL; edge2 = edge->link; if ( blue ) { edge1 = edge; } else if ( edge2 && edge2->blue_edge ) { blue = edge2->blue_edge; edge1 = edge2; edge2 = edge; } if ( !edge1 ) continue; 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; } if ( !anchor ) anchor = edge; } } /* now we will align all 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 || edge2 < edge ) { af_latin_align_linked_edge( hints, dim, edge2, edge ); edge->flags |= AF_EDGE_DONE; continue; } if ( !anchor ) { 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, (AF_Edge_Flags)edge->flags, (AF_Edge_Flags)edge2->flags ); if ( cur_len <= 64 ) u_off = d_off = 32; else { 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 = cur_pos1 + cur_len / 2; } else edge->pos = FT_PIX_ROUND( edge->opos ); anchor = edge; edge->flags |= AF_EDGE_DONE; af_latin_align_linked_edge( hints, dim, edge, edge2 ); } 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, (AF_Edge_Flags)edge->flags, (AF_Edge_Flags)edge2->flags ); if ( cur_len < 96 ) { FT_Pos u_off, d_off; cur_pos1 = FT_PIX_ROUND( org_center ); if (cur_len <= 64 ) u_off = 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; } 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, (AF_Edge_Flags)edge->flags, (AF_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; } edge->flags |= AF_EDGE_DONE; edge2->flags |= AF_EDGE_DONE; if ( edge > edges && edge->pos < edge[-1].pos ) 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++ ) { if ( edge->flags & AF_EDGE_DONE ) continue; if ( edge->serif ) af_latin_align_serif_edge( hints, edge->serif, edge ); else if ( !anchor ) { edge->pos = FT_PIX_ROUND( edge->opos ); anchor = edge; } else edge->pos = anchor->pos + FT_PIX_ROUND( edge->opos - anchor->opos ); edge->flags |= AF_EDGE_DONE; if ( edge > edges && edge->pos < edge[-1].pos ) edge->pos = edge[-1].pos; if ( edge + 1 < edge_limit && edge[1].flags & AF_EDGE_DONE && edge->pos > edge[1].pos ) edge->pos = edge[1].pos; } } } static FT_Error af_latin_hints_apply( AF_GlyphHints hints, FT_Outline* outline, AF_LatinMetrics metrics ) { FT_Error error; int dim; error = af_glyph_hints_reload( hints, outline ); if ( error ) goto Exit; /* analyze glyph outline */ if ( AF_HINTS_DO_HORIZONTAL( hints ) ) { error = af_latin_hints_detect_features( hints, AF_DIMENSION_HORZ ); if ( error ) goto Exit; } if ( AF_HINTS_DO_VERTICAL( hints ) ) { error = af_latin_hints_detect_features( hints, AF_DIMENSION_VERT ); if ( error ) goto Exit; 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 ) ) ) { #ifdef AF_USE_WARPER if ( dim == AF_DIMENSION_HORZ && metrics->root.scaler.render_mode == FT_RENDER_MODE_NORMAL ) { AF_WarperRec warper; FT_Fixed scale; FT_Pos delta; af_warper_compute( &warper, hints, dim, &scale, &delta ); af_glyph_hints_scale_dim( hints, dim, scale, delta ); continue; } #endif 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 *****/ /***** *****/ /*************************************************************************/ /*************************************************************************/ static const AF_Script_UniRangeRec af_latin_uniranges[] = { { 32, 127 }, /* XXX: TODO: Add new Unicode ranges here! */ { 160, 255 }, { 0, 0 } }; FT_CALLBACK_TABLE_DEF const AF_ScriptClassRec af_latin_script_class = { AF_SCRIPT_LATIN, af_latin_uniranges, sizeof( AF_LatinMetricsRec ), (AF_Script_InitMetricsFunc) af_latin_metrics_init, (AF_Script_ScaleMetricsFunc)af_latin_metrics_scale, (AF_Script_DoneMetricsFunc) NULL, (AF_Script_InitHintsFunc) af_latin_hints_init, (AF_Script_ApplyHintsFunc) af_latin_hints_apply }; /* END */