ref: 862b4d5a1fc4deb6962c8bbdb4304cb496ccffb1
dir: /src/autofit/aflatin.c/
#include "aflatin.h"
FT_LOCAL_DEF( void )
af_latin_hints_compute_segments( AF_OutlineHints hints,
AF_Dimension dim )
{
AF_AxisHints axis = &hints->axis[dim];
AF_Segment segments = axis->segments;
AF_Segment segment = segments;
FT_Int num_segments = 0;
AF_Point* contour = hints->contours;
AF_Point* contour_limit = contour + hints->num_contours;
AF_Direction major_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 = ABS( axis->major_dir );
segment_dir = major_dir;
/* set up (u,v) in each point */
af_setup_uv( outline, (dim == AF_DIMENSION_HORZ)
? AF_UV_FXY,
: AF_UV_FYX );
/* 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 ( ABS( last->out_dir ) == major_dir &&
ABS( point->out_dir ) == major_dir )
{
/* we are already on an edge, try to locate its start */
last = point;
for (;;)
{
point = point->prev;
if ( 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 = ( 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 = min_pos;
segment->max_coord = max_pos;
on_edge = 0;
num_segments++;
segment++;
/* fallthrough */
}
}
/* now exit if we are at the start/end point */
if ( point == last )
{
if ( passed )
break;
passed = 1;
}
if ( !on_edge && ABS( point->out_dir ) == major_dir )
{
/* this is the start of a new segment! */
segment_dir = point->out_dir;
/* clear all segment fields */
FT_ZERO( segment );
segment->dir = 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 */
FT_ZERO( segment );
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;
num_segments++;
segment++;
}
/* insert maximum segment */
if ( max_point )
{
/* clear all segment fields */
FT_ZERO( segment );
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;
num_segments++;
segment++;
}
}
#endif /* AF_HINT_METRICS */
axis->num_segments = num_segments;
}
FT_LOCAL_DEF( void )
af_latin_hints_link_segments( AF_OutlineHints 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( void )
af_latin_hints_compute_edges( AF_OutlineHints hints,
AF_Dimension dim )
{
AF_AxisHints axis = &hints->axis[dim];
AF_Edge edges = axis->edges;
AF_Edge edge, edge_limit;
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;
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( outline->edge_distance_threshold,
scale );
if ( edge_distance_threshold > 64 / 4 )
edge_distance_threshold = 64 / 4;
edge_distance_threshold = FT_DivFix( edge_distance_threshold,
scale );
edge_limit = edges;
for ( seg = segments; seg < segment_limit; seg++ )
{
AF_Edge found = 0;
/* look for an edge corresponding to the segment */
for ( edge = edges; edge < edge_limit; edge++ )
{
FT_Pos dist;
dist = seg->pos - edge->fpos;
if ( dist < 0 )
dist = -dist;
if ( dist < edge_distance_threshold )
{
found = edge;
break;
}
}
if ( !found )
{
/* insert a new edge in the list and */
/* sort according to the position */
while ( edge > edges && edge[-1].fpos > seg->pos )
{
edge[0] = edge[-1];
edge--;
}
edge_limit++;
/* clear all edge fields */
FT_MEM_ZERO( edge, sizeof ( *edge ) );
/* add the segment to the new edge's list */
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 = edge->first;
edge->last->edge_next = seg;
edge->last = seg;
}
}
*p_num_edges = (FT_Int)( edge_limit - edges );
/*********************************************************************/
/* */
/* 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 I've tried to remove this loop, setting
* the "edge" field of each segment directly in the
* code above. For some reason, it slows down execution
* speed -- on a Sun.
*/
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;
#ifdef FT_CONFIG_CHESTER_SERIF
if ( is_serif )
{
edge->serif = edge2;
edge2->flags |= AF_EDGE_SERIF;
}
else
edge->link = edge2;
#else /* !FT_CONFIG_CHESTER_SERIF */
if ( is_serif )
edge->serif = edge2;
else
edge->link = edge2;
#endif /* !FT_CONFIG_CHESTER_SERIF */
}
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 = up_dir;
else if ( ups < downs )
edge->dir = -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;
}
}
/*************************************************************************/
/* */
/* <Function> */
/* af_outline_detect_features */
/* */
/* <Description> */
/* Performs feature detection on a given AF_OutlineRec object. */
/* */
FT_LOCAL_DEF( void )
af_latin_hints_detect_features( AF_OutlineHints hints,
AF_Dimension dim )
{
af_latin_hints_compute_segments( hints, dim );
af_latin_hints_link_segments ( hints, dim );
af_latin_hints_compute_edges ( hints dim );
}
/*************************************************************************/
/* */
/* <Function> */
/* af_outline_compute_blue_edges */
/* */
/* <Description> */
/* Computes the `blue edges' in a given outline (i.e. those that must */
/* be snapped to a blue zone edge (top or bottom). */
/* */
FT_LOCAL_DEF( void )
af_latin_hints_compute_blue_edges( AF_OutlineHints outline,
AF_Face_Globals face_globals )
{
AF_Edge edge = outline->horz_edges;
AF_Edge edge_limit = edge + outline->num_hedges;
AF_Globals globals = &face_globals->design;
FT_Fixed y_scale = outline->y_scale;
FT_Bool blue_active[AF_BLUE_MAX];
/* compute which blue zones are active, i.e. have their scaled */
/* size < 3/4 pixels */
{
AF_Blue blue;
FT_Bool check = 0;
for ( blue = AF_BLUE_CAPITAL_TOP; blue < AF_BLUE_MAX; blue++ )
{
FT_Pos ref, shoot, dist;
ref = globals->blue_refs[blue];
shoot = globals->blue_shoots[blue];
dist = ref - shoot;
if ( dist < 0 )
dist = -dist;
blue_active[blue] = 0;
if ( FT_MulFix( dist, y_scale ) < 48 )
{
blue_active[blue] = 1;
check = 1;
}
}
/* return immediately if no blue zone is active */
if ( !check )
return;
}
/* for each horizontal edge search the blue zone which is closest */
for ( ; edge < edge_limit; edge++ )
{
AF_Blue blue;
FT_Pos* best_blue = 0;
FT_Pos best_dist; /* initial threshold */
/* compute the initial threshold as a fraction of the EM size */
best_dist = FT_MulFix( face_globals->face->units_per_EM / 40, y_scale );
#ifdef FT_CONFIG_CHESTER_SMALL_F
if ( best_dist > 64 / 2 )
best_dist = 64 / 2;
#else
if ( best_dist > 64 / 4 )
best_dist = 64 / 4;
#endif
for ( blue = AF_BLUE_CAPITAL_TOP; blue < AF_BLUE_MAX; blue++ )
{
/* 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 XXX */
FT_Bool is_top_blue =
FT_BOOL( AF_IS_TOP_BLUE( blue ) );
FT_Bool is_major_dir =
FT_BOOL( edge->dir == outline->horz_major_dir );
if ( !blue_active[blue] )
continue;
/* 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;
FT_Pos* blue_pos = globals->blue_refs + blue;
/* first of all, compare it to the reference position */
dist = edge->fpos - *blue_pos;
if ( dist < 0 )
dist = -dist;
dist = FT_MulFix( dist, y_scale );
if ( dist < best_dist )
{
best_dist = dist;
best_blue = blue_pos;
}
/* 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_pos );
if ( is_top_blue ^ is_under_ref )
{
blue_pos = globals->blue_shoots + blue;
dist = edge->fpos - *blue_pos;
if ( dist < 0 )
dist = -dist;
dist = FT_MulFix( dist, y_scale );
if ( dist < best_dist )
{
best_dist = dist;
best_blue = blue_pos;
}
}
}
}
}
if ( best_blue )
edge->blue_edge = best_blue;
}
}
/*************************************************************************/
/* */
/* <Function> */
/* af_outline_scale_blue_edges */
/* */
/* <Description> */
/* This function must be called before hinting in order to re-adjust */
/* the contents of the detected edges (basically change the `blue */
/* edge' pointer from `design units' to `scaled ones'). */
/* */
FT_LOCAL_DEF( void )
af_outline_hints_scale_blue_edges( AF_OutlineHints hints ) outline,
{
AF_AxisHints axis = &hints->axis[ AF_DIMENSION_VERT ];
AF_Edge edge = axis->edges;
AF_Edge edge_limit = edge + axis->num_edges;
FT_Pos delta;
delta = globals->scaled.blue_refs - globals->design.blue_refs;
for ( ; edge < edge_limit; edge++ )
{
if ( edge->blue_edge )
edge->blue_edge += delta;
}
}