diff --git a/ChangeLog b/ChangeLog index c0c9796c0..a667c0ace 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,17 @@ +2016-02-27 Werner Lemberg + + [autofit] Properly handle spikes pointing to the x-axis. + + An example that gets better rendered is glyph `uusignTaml' (glyph + index 2286) in font `FreeSerif.ttf' (Version 0412.2263) at 22ppem. + + * src/autofit/aflatin.c (af_latin_hints_compute_segments): Properly + handle segments where the last point of the first segment is + identical to the first point in the second one. This can happen for + malformed fonts or spikes. We either merge the new segment with the + previous one (both segments point into the same direction), or we + discard the shorter segment if they point into different directions. + 2016-02-27 Werner Lemberg [autofit] Minor code clean-up. diff --git a/src/autofit/aflatin.c b/src/autofit/aflatin.c index 41347399d..f94190f6d 100644 --- a/src/autofit/aflatin.c +++ b/src/autofit/aflatin.c @@ -1436,20 +1436,35 @@ /* do each contour separately */ for ( ; contour < contour_limit; contour++ ) { - AF_Point point = contour[0]; - AF_Point last = point->prev; - int on_edge = 0; + 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_Pos min_flags = AF_FLAG_NONE; + FT_Pos 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; + FT_Pos prev_max_pos; + FT_Pos prev_min_coord; + FT_Pos prev_max_coord; + FT_UShort prev_min_flags; + FT_UShort prev_max_flags; + FT_Pos prev_min_on_coord; + FT_Pos prev_max_on_coord; + if ( point == last ) /* skip singletons -- just in case */ continue; @@ -1490,6 +1505,19 @@ 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 ) ) { @@ -1502,37 +1530,149 @@ if ( point->out_dir != segment_dir || point == last ) { - FT_Pos min_coord; - FT_Pos max_coord; + /* 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 */ - /* we are just leaving an edge; record a new segment! */ - segment->last = point; - segment->pos = (FT_Short)( ( min_pos + max_pos ) >> 1 ); + 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, and the length of the on points */ - /* inbetween doesn't exceed a heuristic limit */ - if ( ( segment->first->flags | point->flags ) & AF_FLAG_CONTROL && - ( max_on_coord - min_on_coord ) < flat_threshold ) - segment->flags |= AF_EDGE_ROUND; + /* 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; - /* compute segment size */ - min_coord = max_coord = point->v; + segment->min_coord = (FT_Short)min_coord; + segment->max_coord = (FT_Short)max_coord; + segment->height = segment->max_coord - segment->min_coord; - v = segment->first->v; - if ( v < min_coord ) - min_coord = v; - if ( v > max_coord ) - max_coord = v; + 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 */ - segment->min_coord = (FT_Short)min_coord; - segment->max_coord = (FT_Short)max_coord; - segment->height = (FT_Short)( segment->max_coord - - segment->min_coord ); + 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 ); + + 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 ); + } + 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 ); + + 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 */ } } @@ -1561,7 +1701,9 @@ segment->first = point; segment->last = point; - min_pos = max_pos = point->u; + min_pos = max_pos = point->u; + min_coord = max_coord = point->v; + min_flags = max_flags = point->flags; if ( point->flags & AF_FLAG_CONTROL ) {