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path: root/freetype/src/autofit/aflatin.c
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Diffstat (limited to 'freetype/src/autofit/aflatin.c')
-rw-r--r--freetype/src/autofit/aflatin.c221
1 files changed, 174 insertions, 47 deletions
diff --git a/freetype/src/autofit/aflatin.c b/freetype/src/autofit/aflatin.c
index e6f4dfb05..40ec20faa 100644
--- a/freetype/src/autofit/aflatin.c
+++ b/freetype/src/autofit/aflatin.c
@@ -171,7 +171,15 @@
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;
@@ -298,6 +306,14 @@
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 )
@@ -520,6 +536,13 @@
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;
@@ -552,7 +575,6 @@
{
FT_Bool l2r;
FT_Pos d;
- FT_Int p_first, p_last;
if ( !hit )
@@ -688,6 +710,13 @@
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" ));
}
@@ -758,6 +787,8 @@
blue->flags = 0;
if ( AF_LATIN_IS_TOP_BLUE( bs ) )
blue->flags |= AF_LATIN_BLUE_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
@@ -1262,17 +1293,19 @@
/* 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[0] = seg0;
+ /* clear all segment fields */
+ segment[0] = seg0;
+
segment->dir = (FT_Char)segment_dir;
min_pos = max_pos = point->u;
segment->first = point;
segment->last = point;
- on_edge = 1;
+
+ on_edge = 1;
}
point = point->next;
@@ -1296,9 +1329,6 @@
FT_Pos last_v = last->v;
- if ( first == last )
- continue;
-
if ( first_v < last_v )
{
AF_Point p;
@@ -1337,31 +1367,44 @@
}
- /* Link segments to form stems and serifs. */
+ /* 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 = segments + axis->num_segments;
- FT_Pos len_threshold, len_score;
+ 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++ )
{
- /* the fake segments are introduced to hint the metrics -- */
- /* we must never link them to anything */
- if ( seg1->dir != axis->major_dir || seg1->first == seg1->last )
+ if ( seg1->dir != axis->major_dir )
continue;
/* search for stems having opposite directions, */
@@ -1375,10 +1418,9 @@
if ( seg1->dir + seg2->dir == 0 && pos2 > pos1 )
{
/* compute distance between the two segments */
- FT_Pos dist = pos2 - pos1;
- FT_Pos min = seg1->min_coord;
- FT_Pos max = seg1->max_coord;
- FT_Pos len, score;
+ FT_Pos min = seg1->min_coord;
+ FT_Pos max = seg1->max_coord;
+ FT_Pos len;
if ( min < seg2->min_coord )
@@ -1388,15 +1430,49 @@
max = seg2->max_coord;
/* compute maximum coordinate difference of the two segments */
+ /* (this is, how much they overlap) */
len = max - min;
if ( len >= len_threshold )
{
- /* small coordinate differences cause a higher score, and */
- /* segments with a greater distance cause a higher score also */
- score = dist + len_score / len;
+ /*
+ * 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.
+ *
+ * o The less overlapping along the main axis, the worse it
+ * is, causing a larger demerit.
+ *
+ * o 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 */
- /* of the sum of the two values */
if ( score < seg1->score )
{
seg1->score = score;
@@ -1728,6 +1804,8 @@
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;
@@ -1736,7 +1814,7 @@
error = af_latin_hints_compute_segments( hints, dim );
if ( !error )
{
- af_latin_hints_link_segments( hints, dim );
+ af_latin_hints_link_segments( hints, width_count, widths, dim );
error = af_latin_hints_compute_edges( hints, dim );
}
@@ -1765,8 +1843,9 @@
for ( ; edge < edge_limit; edge++ )
{
FT_UInt bb;
- AF_Width best_blue = NULL;
- FT_Pos best_dist; /* initial threshold */
+ 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 */
@@ -1780,24 +1859,26 @@
for ( bb = 0; bb < latin->blue_count; bb++ )
{
AF_LatinBlue blue = latin->blues + bb;
- FT_Bool is_top_blue, is_major_dir;
+ 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 -- 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 )
+ /* 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 ) != 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;
@@ -1810,15 +1891,19 @@
dist = FT_MulFix( dist, scale );
if ( dist < best_dist )
{
- best_dist = dist;
- best_blue = &blue->ref;
+ 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 */
- if ( edge->flags & AF_EDGE_ROUND && dist != 0 )
+ /* 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 );
@@ -1832,8 +1917,9 @@
dist = FT_MulFix( dist, scale );
if ( dist < best_dist )
{
- best_dist = dist;
- best_blue = &blue->shoot;
+ best_dist = dist;
+ best_blue = &blue->shoot;
+ best_blue_is_neutral = is_neutral_blue;
}
}
}
@@ -1841,7 +1927,11 @@
}
if ( best_blue )
+ {
edge->blue_edge = best_blue;
+ if ( best_blue_is_neutral )
+ edge->flags |= AF_EDGE_NEUTRAL;
+ }
}
}
@@ -2159,7 +2249,7 @@
FT_TRACE5(( " LINK: edge %d (opos=%.2f) linked to %.2f,"
" dist was %.2f, now %.2f\n",
- stem_edge-hints->axis[dim].edges, stem_edge->opos / 64.0,
+ stem_edge - hints->axis[dim].edges, stem_edge->opos / 64.0,
stem_edge->pos / 64.0, dist / 64.0, fitted_width / 64.0 ));
}
@@ -2226,14 +2316,41 @@
if ( edge->flags & AF_EDGE_DONE )
continue;
- blue = edge->blue_edge;
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 ( ( neutral && neutral2 ) || 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 stem is aligned to a blue zone */
+ /* flip edges if the other edge is aligned to a blue zone */
else if ( edge2 && edge2->blue_edge )
{
blue = edge2->blue_edge;
@@ -2300,7 +2417,7 @@
/* this should not happen, but it's better to be safe */
if ( edge2->blue_edge )
{
- FT_TRACE5(( " ASSERTION FAILED for edge %d\n", edge2-edges ));
+ FT_TRACE5(( " ASSERTION FAILED for edge %d\n", edge2 - edges ));
af_latin_align_linked_edge( hints, dim, edge2, edge );
edge->flags |= AF_EDGE_DONE;
@@ -2689,6 +2806,8 @@
FT_Error error;
int dim;
+ AF_LatinAxis axis;
+
error = af_glyph_hints_reload( hints, outline );
if ( error )
@@ -2702,14 +2821,22 @@
if ( AF_HINTS_DO_HORIZONTAL( hints ) )
#endif
{
- error = af_latin_hints_detect_features( hints, AF_DIMENSION_HORZ );
+ 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 ) )
{
- error = af_latin_hints_detect_features( hints, AF_DIMENSION_VERT );
+ 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;
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-19 10:01:33 +0000