ref: 7e10ee403c008f0b080f5e685f16f0f828a15d00
dir: /src/autohint/ahglyph.c/
/***************************************************************************/
/* */
/* ahglyph.c */
/* */
/* Routines used to load and analyze a given glyph before hinting */
/* (body). */
/* */
/* Copyright 2000 Catharon Productions Inc. */
/* Author: David Turner */
/* */
/* This file is part of the Catharon Typography Project and shall only */
/* be used, modified, and distributed under the terms of the Catharon */
/* Open Source License that should come with this file under the name */
/* `CatharonLicense.txt'. By continuing to use, modify, or distribute */
/* this file you indicate that you have read the license and */
/* understand and accept it fully. */
/* */
/* Note that this license is compatible with the FreeType license. */
/* */
/***************************************************************************/
#ifdef FT_FLAT_COMPILE
#include "ahglyph.h"
#include "ahangles.h"
#include "ahglobal.h"
#else
#include <autohint/ahglyph.h>
#include <autohint/ahangles.h>
#include <autohint/ahglobal.h>
#endif
#include <stdio.h>
#define xxxAH_DEBUG_GLYPH
/* compute the direction value of a given vector.. */
static
AH_Direction ah_compute_direction( FT_Pos dx,
FT_Pos dy )
{
AH_Direction dir;
FT_Pos ax = ABS( dx );
FT_Pos ay = ABS( dy );
dir = ah_dir_none;
/* test for vertical direction */
if ( ax * 12 < ay )
{
dir = dy > 0 ? ah_dir_up : ah_dir_down;
}
/* test for horizontal direction */
else if ( ay * 12 < ax )
{
dir = dx > 0 ? ah_dir_right : ah_dir_left;
}
return dir;
}
/* this function is used by ah_get_orientation (see below) to test */
/* the fill direction of a given bbox extrema */
static
int ah_test_extrema( FT_Outline* outline,
int n )
{
FT_Vector *prev, *cur, *next;
FT_Pos product;
FT_Int first, last, c;
/* we need to compute the `previous' and `next' point */
/* for these extrema */
cur = outline->points + n;
prev = cur - 1;
next = cur + 1;
first = 0;
for ( c = 0; c < outline->n_contours; c++ )
{
last = outline->contours[c];
if ( n == first )
prev = outline->points + last;
if ( n == last )
next = outline->points + first;
first = last + 1;
}
product = FT_MulDiv( cur->x - prev->x, /* in.x */
next->y - cur->y, /* out.y */
0x40 )
-
FT_MulDiv( cur->y - prev->y, /* in.y */
next->x - cur->x, /* out.x */
0x40 );
if ( product )
product = product > 0 ? 2 : 1;
return product;
}
/* Compute the orientation of path filling. It differs between TrueType */
/* and Type1 formats. We could use the `ft_outline_reverse_fill' flag, */
/* but it is better to re-compute it directly (it seems that this flag */
/* isn't correctly set for some weird composite glyphs currently). */
/* */
/* We do this by computing bounding box points, and computing their */
/* curvature. */
/* */
/* The function returns either 1 or -1. */
/* */
static
int ah_get_orientation( FT_Outline* outline )
{
FT_BBox box;
FT_BBox indices;
int n, last;
indices.xMin = -1;
indices.yMin = -1;
indices.xMax = -1;
indices.yMax = -1;
box.xMin = box.yMin = 32767;
box.xMax = box.yMax = -32768;
/* is it empty? */
if ( outline->n_contours < 1 )
return 1;
last = outline->contours[outline->n_contours - 1];
for ( n = 0; n <= last; n++ )
{
FT_Pos x, y;
x = outline->points[n].x;
if ( x < box.xMin )
{
box.xMin = x;
indices.xMin = n;
}
if ( x > box.xMax )
{
box.xMax = x;
indices.xMax = n;
}
y = outline->points[n].y;
if ( y < box.yMin )
{
box.yMin = y;
indices.yMin = n;
}
if ( y > box.yMax )
{
box.yMax = y;
indices.yMax = n;
}
}
/* test orientation of the xmin */
n = ah_test_extrema( outline, indices.xMin );
if ( n )
goto Exit;
n = ah_test_extrema( outline, indices.yMin );
if ( n )
goto Exit;
n = ah_test_extrema( outline, indices.xMax );
if ( n )
goto Exit;
n = ah_test_extrema( outline, indices.yMax );
if ( !n )
n = 1;
Exit:
return n;
}
/*************************************************************************/
/* */
/* <Function> */
/* ah_outline_new */
/* */
/* <Description> */
/* Creates a new and empty AH_Outline object. */
/* */
FT_LOCAL_DEF
FT_Error ah_outline_new( FT_Memory memory,
AH_Outline** aoutline )
{
FT_Error error;
AH_Outline* outline;
if ( !ALLOC( outline, sizeof ( *outline ) ) )
{
outline->memory = memory;
*aoutline = outline;
}
return error;
}
/*************************************************************************/
/* */
/* <Function> */
/* ah_outline_done */
/* */
/* <Description> */
/* Destroys a given AH_Outline object. */
/* */
FT_LOCAL_DEF
void ah_outline_done( AH_Outline* outline )
{
FT_Memory memory = outline->memory;
FREE( outline->horz_edges );
FREE( outline->horz_segments );
FREE( outline->contours );
FREE( outline->points );
FREE( outline );
}
/*************************************************************************/
/* */
/* <Function> */
/* ah_outline_save */
/* */
/* <Description> */
/* Saves the content of a given AH_Outline object into a face's glyph */
/* slot. */
/* */
FT_LOCAL_DEF
void ah_outline_save( AH_Outline* outline,
AH_Loader* gloader )
{
AH_Point* point = outline->points;
AH_Point* point_limit = point + outline->num_points;
FT_Vector* vec = gloader->current.outline.points;
char* tag = gloader->current.outline.tags;
/* we assume that the glyph loader has already been checked for storage */
for ( ; point < point_limit; point++, vec++, tag++ )
{
vec->x = point->x;
vec->y = point->y;
if ( point->flags & ah_flah_conic )
tag[0] = FT_Curve_Tag_Conic;
else if ( point->flags & ah_flah_cubic )
tag[0] = FT_Curve_Tag_Cubic;
else
tag[0] = FT_Curve_Tag_On;
}
}
/*************************************************************************/
/* */
/* <Function> */
/* ah_outline_load */
/* */
/* <Description> */
/* Loads an unscaled outline from a glyph slot into an AH_Outline */
/* object. */
/* */
FT_LOCAL_DEF
FT_Error ah_outline_load( AH_Outline* outline,
FT_Face face )
{
FT_Memory memory = outline->memory;
FT_Error error = FT_Err_Ok;
FT_Outline* source = &face->glyph->outline;
FT_Int num_points = source->n_points;
FT_Int num_contours = source->n_contours;
AH_Point* points;
/* check arguments */
if ( !face ||
!face->size ||
face->glyph->format != ft_glyph_format_outline )
return FT_Err_Invalid_Argument;
/* first of all, reallocate the contours array if necessary */
if ( num_contours > outline->max_contours )
{
FT_Int new_contours = ( num_contours + 3 ) & -4;
if ( REALLOC_ARRAY( outline->contours, outline->max_contours,
new_contours, AH_Point* ) )
goto Exit;
outline->max_contours = new_contours;
}
/* then, reallocate the points, segments & edges arrays if needed -- */
/* note that we reserved two additional point positions, used to */
/* hint metrics appropriately */
/* */
if ( num_points + 2 > outline->max_points )
{
FT_Int news = ( num_points + 2 + 7 ) & -8;
FT_Int max = outline->max_points;
if ( REALLOC_ARRAY( outline->points,
max, news, AH_Point ) ||
REALLOC_ARRAY( outline->horz_edges,
max * 2, news * 2, AH_Edge ) ||
REALLOC_ARRAY( outline->horz_segments,
max * 2, news * 2, AH_Segment ) )
goto Exit;
/* readjust some pointers */
outline->vert_edges = outline->horz_edges + news;
outline->vert_segments = outline->horz_segments + news;
outline->max_points = news;
}
outline->num_points = num_points;
outline->num_contours = num_contours;
outline->num_hedges = 0;
outline->num_vedges = 0;
outline->num_hsegments = 0;
outline->num_vsegments = 0;
#if 1
/* We can't rely on the value of `FT_Outline.flags' to know the fill */
/* direction used for a glyph, given that some fonts are broken (e.g. */
/* the Arphic ones). We thus recompute it each time we need to. */
/* */
outline->vert_major_dir = ah_dir_up;
outline->horz_major_dir = ah_dir_left;
if ( ah_get_orientation( source ) > 1 )
{
outline->vert_major_dir = ah_dir_down;
outline->horz_major_dir = ah_dir_right;
}
#else
/* Compute the vertical and horizontal major directions; this is */
/* currently done by inspecting the `ft_outline_reverse_fill' flag. */
/* However, some fonts have improper glyphs, and it'd be a good idea */
/* to be able to re-compute these values on the fly. */
outline->vert_major_dir = ah_dir_up;
outline->horz_major_dir = ah_dir_left;
if ( source->flags & ft_outline_reverse_fill )
{
outline->vert_major_dir = ah_dir_down;
outline->horz_major_dir = ah_dir_right;
}
#endif /* 1 */
outline->x_scale = face->size->metrics.x_scale;
outline->y_scale = face->size->metrics.y_scale;
points = outline->points;
if ( outline->num_points == 0 )
goto Exit;
{
/* do one thing at a time -- it is easier to understand, and */
/* the code is clearer */
AH_Point* point;
AH_Point* point_limit = points + outline->num_points;
/* compute coordinates */
{
FT_Vector* vec = source->points;
FT_Fixed x_scale = outline->x_scale;
FT_Fixed y_scale = outline->y_scale;
for ( point = points; point < point_limit; vec++, point++ )
{
point->fx = vec->x;
point->fy = vec->y;
point->ox = point->x = FT_MulFix( vec->x, x_scale );
point->oy = point->y = FT_MulFix( vec->y, y_scale );
point->flags = 0;
}
}
/* compute Bezier flags */
{
char* tag = source->tags;
for ( point = points; point < point_limit; point++, tag++ )
{
switch ( FT_CURVE_TAG( *tag ) )
{
case FT_Curve_Tag_Conic:
point->flags = ah_flah_conic; break;
case FT_Curve_Tag_Cubic:
point->flags = ah_flah_cubic; break;
default:
;
}
}
}
/* compute `next' and `prev' */
{
FT_Int contour_index;
AH_Point* prev;
AH_Point* first;
AH_Point* end;
contour_index = 0;
first = points;
end = points + source->contours[0];
prev = end;
for ( point = points; point < point_limit; point++ )
{
point->prev = prev;
if ( point < end )
{
point->next = point + 1;
prev = point;
}
else
{
point->next = first;
contour_index++;
if ( point + 1 < point_limit )
{
end = points + source->contours[contour_index];
first = point + 1;
prev = end;
}
}
}
}
/* set-up the contours array */
{
AH_Point** contour = outline->contours;
AH_Point** contour_limit = contour + outline->num_contours;
short* end = source->contours;
short index = 0;
for ( ; contour < contour_limit; contour++, end++ )
{
contour[0] = points + index;
index = end[0] + 1;
}
}
/* compute directions of in & out vectors */
{
for ( point = points; point < point_limit; point++ )
{
AH_Point* prev;
AH_Point* next;
FT_Vector vec;
prev = point->prev;
vec.x = point->fx - prev->fx;
vec.y = point->fy - prev->fy;
point->in_dir = ah_compute_direction( vec.x, vec.y );
#ifndef AH_OPTION_NO_WEAK_INTERPOLATION
point->in_angle = ah_angle( &vec );
#endif
next = point->next;
vec.x = next->fx - point->fx;
vec.y = next->fy - point->fy;
point->out_dir = ah_compute_direction( vec.x, vec.y );
#ifndef AH_OPTION_NO_WEAK_INTERPOLATION
point->out_angle = ah_angle( &vec );
{
AH_Angle delta = point->in_angle - point->out_angle;
if ( delta < 0 )
delta = -delta;
if ( delta < 2 )
point->flags |= ah_flah_weak_interpolation;
}
#if 0
if ( point->flags & ( ah_flah_conic | ah_flah_cubic ) )
point->flags |= ah_flah_weak_interpolation;
#endif
#endif /* !AH_OPTION_NO_WEAK_INTERPOLATION */
#ifdef AH_OPTION_NO_STRONG_INTERPOLATION
point->flags |= ah_flah_weak_interpolation;
#endif
}
}
}
Exit:
return error;
}
FT_LOCAL_DEF
void ah_setup_uv( AH_Outline* outline,
AH_UV source )
{
AH_Point* point = outline->points;
AH_Point* point_limit = point + outline->num_points;
for ( ; point < point_limit; point++ )
{
FT_Pos u, v;
switch ( source )
{
case ah_uv_fxy:
u = point->fx;
v = point->fy;
break;
case ah_uv_fyx:
u = point->fy;
v = point->fx;
break;
case ah_uv_oxy:
u = point->ox;
v = point->oy;
break;
case ah_uv_oyx:
u = point->oy;
v = point->ox;
break;
case ah_uv_yx:
u = point->y;
v = point->x;
break;
case ah_uv_ox:
u = point->x;
v = point->ox;
break;
case ah_uv_oy:
u = point->y;
v = point->oy;
break;
default:
u = point->x;
v = point->y;
break;
}
point->u = u;
point->v = v;
}
}
FT_LOCAL_DEF
void ah_outline_compute_segments( AH_Outline* outline )
{
int dimension;
AH_Segment* segments;
FT_Int* p_num_segments;
AH_Direction segment_dir;
AH_Direction major_dir;
segments = outline->horz_segments;
p_num_segments = &outline->num_hsegments;
major_dir = ah_dir_right; /* This value must be positive! */
segment_dir = major_dir;
/* set up (u,v) in each point */
ah_setup_uv( outline, ah_uv_fyx );
for ( dimension = 1; dimension >= 0; dimension-- )
{
AH_Point** contour = outline->contours;
AH_Point** contour_limit = contour + outline->num_contours;
AH_Segment* segment = segments;
FT_Int num_segments = 0;
#ifdef AH_HINT_METRICS
AH_Point* min_point = 0;
AH_Point* max_point = 0;
FT_Pos min_coord = 32000;
FT_Pos max_coord = -32000;
#endif
/* do each contour separately */
for ( ; contour < contour_limit; contour++ )
{
AH_Point* point = contour[0];
AH_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 AH_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 ) &
ah_flah_control )
segment->flags |= ah_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 */
memset( segment, 0, sizeof ( *segment ) );
segment->dir = segment_dir;
segment->flags = ah_edge_normal;
min_pos = max_pos = point->u;
segment->first = point;
segment->last = point;
segment->contour = contour;
on_edge = 1;
#ifdef AH_HINT_METRICS
if ( point == max_point )
max_point = 0;
if ( point == min_point )
min_point = 0;
#endif
}
point = point->next;
}
} /* contours */
#ifdef AH_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 ( dimension == 0 )
{
AH_Point* point = outline->points;
AH_Point* point_limit = point + outline->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 */
memset( segment, 0, sizeof ( *segment ) );
segment->dir = segment_dir;
segment->flags = ah_edge_normal;
segment->first = min_point;
segment->last = min_point;
segment->pos = min_pos;
num_segments++;
segment++;
}
/* insert maximum segment */
if ( max_point )
{
/* clear all segment fields */
memset( segment, 0, sizeof ( *segment ) );
segment->dir = segment_dir;
segment->flags = ah_edge_normal;
segment->first = max_point;
segment->last = max_point;
segment->pos = max_pos;
num_segments++;
segment++;
}
}
#endif /* AH_HINT_METRICS */
*p_num_segments = num_segments;
segments = outline->vert_segments;
major_dir = ah_dir_up;
p_num_segments = &outline->num_vsegments;
ah_setup_uv( outline, ah_uv_fxy );
}
}
FT_LOCAL_DEF
void ah_outline_link_segments( AH_Outline* outline )
{
AH_Segment* segments;
AH_Segment* segment_limit;
int dimension;
ah_setup_uv( outline, ah_uv_fyx );
segments = outline->horz_segments;
segment_limit = segments + outline->num_hsegments;
for ( dimension = 1; dimension >= 0; dimension-- )
{
AH_Segment* seg1;
AH_Segment* seg2;
/* now compare each segment to the others */
for ( seg1 = segments; seg1 < segment_limit; seg1++ )
{
FT_Pos best_score = 32000;
AH_Segment* best_segment = 0;
/* the fake segments are introduced to hint the metrics -- */
/* we must never link them to anything */
if ( seg1->first == seg1->last )
continue;
for ( seg2 = segments; seg2 < segment_limit; seg2++ )
if ( seg1 != seg2 && seg1->dir + seg2->dir == 0 )
{
FT_Pos pos1 = seg1->pos;
FT_Pos pos2 = seg2->pos;
FT_Bool is_dir;
FT_Bool is_pos;
/* check that the segments are correctly oriented and */
/* positioned to form a black distance */
is_dir = ( seg1->dir == outline->horz_major_dir ||
seg1->dir == outline->vert_major_dir );
is_pos = pos1 > pos2;
if ( pos1 == pos2 || !(is_dir ^ is_pos) )
continue;
/* Check the two segments. We now have a better algorithm */
/* that doesn't rely on the segment points themselves but */
/* on their relative position. This gets rids of many */
/* unpleasant artefacts and incorrect stem/serifs */
/* computations. */
/* first of all, compute the size of the `common' height */
{
FT_Pos min = seg1->min_coord;
FT_Pos max = seg1->max_coord;
FT_Pos len, score;
FT_Pos size1, size2;
size1 = max - min;
size2 = seg2->max_coord - seg2->min_coord;
if ( min < seg2->min_coord )
min = seg2->min_coord;
if ( max < seg2->max_coord )
max = seg2->max_coord;
len = max - min;
score = seg2->pos - seg1->pos;
if ( score < 0 )
score = -score;
/* before comparing the scores, take care that the segments */
/* are really facing each other (often not for italics..) */
if ( 4 * len >= size1 && 4 * len >= size2 )
if ( score < best_score )
{
best_score = score;
best_segment = seg2;
}
}
}
if ( best_segment )
{
seg1->link = best_segment;
seg1->score = best_score;
best_segment->num_linked++;
}
} /* edges 1 */
/* now, compute the `serif' segments */
for ( seg1 = segments; seg1 < segment_limit; seg1++ )
{
seg2 = seg1->link;
if ( seg2 && seg2->link != seg1 )
{
seg1->link = 0;
seg1->serif = seg2->link;
}
}
ah_setup_uv( outline, ah_uv_fxy );
segments = outline->vert_segments;
segment_limit = segments + outline->num_vsegments;
}
}
#ifdef AH_DEBUG_GLYPH
/* A function used to dump the array of linked segments */
void ah_dump_segments( AH_Outline* outline )
{
AH_Segment* segments;
AH_Segment* segment_limit;
AH_Point* points;
FT_Int dimension;
points = outline->points;
segments = outline->horz_segments;
segment_limit = segments + outline->num_hsegments;
for ( dimension = 1; dimension >= 0; dimension-- )
{
AH_Segment* seg;
printf ( "Table of %s segments:\n",
!dimension ? "vertical" : "horizontal" );
printf ( " [ index | pos | dir | link | serif |"
" numl | first | start ]\n" );
for ( seg = segments; seg < segment_limit; seg++ )
{
printf ( " [ %5d | %4d | %5s | %4d | %5d | %4d | %5d | %5d ]\n",
seg - segments,
(int)seg->pos,
seg->dir == ah_dir_up
? "up"
: ( seg->dir == ah_dir_down
? "down"
: ( seg->dir == ah_dir_left
? "left"
: ( seg->dir == ah_dir_right
? "right"
: "none" ) ) ),
seg->link ? (seg->link-segments) : -1,
seg->serif ? (seg->serif-segments) : -1,
(int)seg->num_linked,
seg->first - points,
seg->last - points );
}
segments = outline->vert_segments;
segment_limit = segments + outline->num_vsegments;
}
}
#endif /* AH_DEBUG_GLYPH */
static
void ah_outline_compute_edges( AH_Outline* outline )
{
AH_Edge* edges;
AH_Segment* segments;
AH_Segment* segment_limit;
AH_Direction up_dir;
FT_Int* p_num_edges;
FT_Int dimension;
FT_Fixed scale;
FT_Pos edge_distance_threshold;
edges = outline->horz_edges;
segments = outline->horz_segments;
segment_limit = segments + outline->num_hsegments;
p_num_edges = &outline->num_hedges;
up_dir = ah_dir_right;
scale = outline->y_scale;
for ( dimension = 1; dimension >= 0; dimension-- )
{
AH_Edge* edge;
AH_Edge* edge_limit; /* really == edge + num_edges */
AH_Segment* seg;
/*********************************************************************/
/* */
/* 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_limit = edges;
for ( seg = segments; seg < segment_limit; seg++ )
{
AH_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;
dist = FT_MulFix( dist, scale );
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 */
memset( edge, 0, 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 = 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, straigth 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 */
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++ )
{
int is_round = 0; /* does it contain round segments? */
int is_straight = 0; /* does it contain straight segments? */
int ups = 0; /* number of upwards segments */
int downs = 0; /* number of downwards segments */
seg = edge->first;
do
{
FT_Bool is_serif;
/* check for roundness of segment */
if ( seg->flags & ah_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 = seg->serif && seg->serif->edge != edge;
if ( seg->link || is_serif )
{
AH_Edge* edge2;
AH_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;
else
edge->link = edge2;
}
seg = seg->edge_next;
} while ( seg != edge->first );
/* set the round/straight flags */
edge->flags = ah_edge_normal;
if ( is_straight == 0 && is_round )
edge->flags |= ah_edge_round;
/* set the edge's main direction */
edge->dir = ah_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;
}
edges = outline->vert_edges;
segments = outline->vert_segments;
segment_limit = segments + outline->num_vsegments;
p_num_edges = &outline->num_vedges;
up_dir = ah_dir_up;
scale = outline->x_scale;
}
}
/*************************************************************************/
/* */
/* <Function> */
/* ah_outline_detect_features */
/* */
/* <Description> */
/* Performs feature detection on a given AH_Outline object. */
/* */
FT_LOCAL_DEF
void ah_outline_detect_features( AH_Outline* outline )
{
ah_outline_compute_segments( outline );
ah_outline_link_segments ( outline );
ah_outline_compute_edges ( outline );
}
/*************************************************************************/
/* */
/* <Function> */
/* ah_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 ah_outline_compute_blue_edges( AH_Outline* outline,
AH_Face_Globals* face_globals )
{
AH_Edge* edge = outline->horz_edges;
AH_Edge* edge_limit = edge + outline->num_hedges;
AH_Globals* globals = &face_globals->design;
FT_Fixed y_scale = outline->y_scale;
/* compute for each horizontal edge, which blue zone is closer */
for ( ; edge < edge_limit; edge++ )
{
AH_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 );
if ( best_dist > 64 / 4 )
best_dist = 64 / 4;
for ( blue = ah_blue_capital_top; blue < ah_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 = AH_IS_TOP_BLUE( blue );
FT_Bool is_major_dir = edge->dir == outline->horz_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;
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 & ah_edge_round && dist != 0 )
{
FT_Bool is_under_ref = 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> */
/* ah_outline_scale_blue_edges */
/* */
/* <Description> */
/* This functions 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 ah_outline_scale_blue_edges( AH_Outline* outline,
AH_Face_Globals* globals )
{
AH_Edge* edge = outline->horz_edges;
AH_Edge* edge_limit = edge + outline->num_hedges;
FT_Int delta;
delta = globals->scaled.blue_refs - globals->design.blue_refs;
for ( ; edge < edge_limit; edge++ )
{
if ( edge->blue_edge )
edge->blue_edge += delta;
}
}
#ifdef AH_DEBUG_GLYPH
void ah_dump_edges( AH_Outline* outline )
{
AH_Edge* edges;
AH_Edge* edge_limit;
AH_Segment* segments;
FT_Int dimension;
edges = outline->horz_edges;
edge_limit = edges + outline->num_hedges;
segments = outline->horz_segments;
for ( dimension = 1; dimension >= 0; dimension-- )
{
AH_Edge* edge;
printf ( "Table of %s edges:\n",
!dimension ? "vertical" : "horizontal" );
printf ( " [ index | pos | dir | link |"
" serif | blue | opos | pos ]\n" );
for ( edge = edges; edge < edge_limit; edge++ )
{
printf ( " [ %5d | %4d | %5s | %4d | %5d | %c | %5.2f | %5.2f ]\n",
edge - edges,
(int)edge->fpos,
edge->dir == ah_dir_up
? "up"
: ( edge->dir == ah_dir_down
? "down"
: ( edge->dir == ah_dir_left
? "left"
: ( edge->dir == ah_dir_right
? "right"
: "none" ) ) ),
edge->link ? ( edge->link - edges ) : -1,
edge->serif ? ( edge->serif - edges ) : -1,
edge->blue_edge ? 'y' : 'n',
edge->opos / 64.0,
edge->pos / 64.0 );
}
edges = outline->vert_edges;
edge_limit = edges + outline->num_vedges;
segments = outline->vert_segments;
}
}
#endif /* AH_DEBUG_GLYPH */
/* END */