ref: d8ac180c8829b94845f31a8baea5a2573fffee42
dir: /src/autofit/afhints.c/
/****************************************************************************
*
* afhints.c
*
* Auto-fitter hinting routines (body).
*
* Copyright (C) 2003-2021 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 "afhints.h"
#include "aferrors.h"
#include <freetype/internal/ftcalc.h>
#include <freetype/internal/ftdebug.h>
/**************************************************************************
*
* The macro FT_COMPONENT is used in trace mode. It is an implicit
* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log
* messages during execution.
*/
#undef FT_COMPONENT
#define FT_COMPONENT afhints
/* Get new segment for given axis. */
FT_LOCAL_DEF( FT_Error )
af_axis_hints_new_segment( AF_AxisHints axis,
FT_Memory memory,
AF_Segment *asegment )
{
FT_Error error = FT_Err_Ok;
AF_Segment segment = NULL;
if ( axis->num_segments < AF_SEGMENTS_EMBEDDED )
{
if ( !axis->segments )
{
axis->segments = axis->embedded.segments;
axis->max_segments = AF_SEGMENTS_EMBEDDED;
}
}
else if ( axis->num_segments >= axis->max_segments )
{
FT_Int old_max = axis->max_segments;
FT_Int new_max = old_max;
FT_Int big_max = (FT_Int)( FT_INT_MAX / sizeof ( *segment ) );
if ( old_max >= big_max )
{
error = FT_THROW( Out_Of_Memory );
goto Exit;
}
new_max += ( new_max >> 2 ) + 4;
if ( new_max < old_max || new_max > big_max )
new_max = big_max;
if ( axis->segments == axis->embedded.segments )
{
if ( FT_NEW_ARRAY( axis->segments, new_max ) )
goto Exit;
ft_memcpy( axis->segments, axis->embedded.segments,
sizeof ( axis->embedded.segments ) );
}
else
{
if ( FT_RENEW_ARRAY( axis->segments, old_max, new_max ) )
goto Exit;
}
axis->max_segments = new_max;
}
segment = axis->segments + axis->num_segments++;
Exit:
*asegment = segment;
return error;
}
/* Get new edge for given axis, direction, and position, */
/* without initializing the edge itself. */
FT_LOCAL( FT_Error )
af_axis_hints_new_edge( AF_AxisHints axis,
FT_Int fpos,
AF_Direction dir,
FT_Bool top_to_bottom_hinting,
FT_Memory memory,
AF_Edge *anedge )
{
FT_Error error = FT_Err_Ok;
AF_Edge edge = NULL;
AF_Edge edges;
if ( axis->num_edges < AF_EDGES_EMBEDDED )
{
if ( !axis->edges )
{
axis->edges = axis->embedded.edges;
axis->max_edges = AF_EDGES_EMBEDDED;
}
}
else if ( axis->num_edges >= axis->max_edges )
{
FT_Int old_max = axis->max_edges;
FT_Int new_max = old_max;
FT_Int big_max = (FT_Int)( FT_INT_MAX / sizeof ( *edge ) );
if ( old_max >= big_max )
{
error = FT_THROW( Out_Of_Memory );
goto Exit;
}
new_max += ( new_max >> 2 ) + 4;
if ( new_max < old_max || new_max > big_max )
new_max = big_max;
if ( axis->edges == axis->embedded.edges )
{
if ( FT_NEW_ARRAY( axis->edges, new_max ) )
goto Exit;
ft_memcpy( axis->edges, axis->embedded.edges,
sizeof ( axis->embedded.edges ) );
}
else
{
if ( FT_RENEW_ARRAY( axis->edges, old_max, new_max ) )
goto Exit;
}
axis->max_edges = new_max;
}
edges = axis->edges;
edge = edges + axis->num_edges;
while ( edge > edges )
{
if ( top_to_bottom_hinting ? ( edge[-1].fpos > fpos )
: ( edge[-1].fpos < fpos ) )
break;
/* we want the edge with same position and minor direction */
/* to appear before those in the major one in the list */
if ( edge[-1].fpos == fpos && dir == axis->major_dir )
break;
edge[0] = edge[-1];
edge--;
}
axis->num_edges++;
Exit:
*anedge = edge;
return error;
}
#ifdef FT_DEBUG_AUTOFIT
#include FT_CONFIG_STANDARD_LIBRARY_H
/* The dump functions are used in the `ftgrid' demo program, too. */
#define AF_DUMP( varformat ) \
do \
{ \
if ( to_stdout ) \
printf varformat; \
else \
FT_TRACE7( varformat ); \
} while ( 0 )
static const char*
af_dir_str( AF_Direction dir )
{
const char* result;
switch ( dir )
{
case AF_DIR_UP:
result = "up";
break;
case AF_DIR_DOWN:
result = "down";
break;
case AF_DIR_LEFT:
result = "left";
break;
case AF_DIR_RIGHT:
result = "right";
break;
default:
result = "none";
}
return result;
}
#define AF_INDEX_NUM( ptr, base ) (int)( (ptr) ? ( (ptr) - (base) ) : -1 )
static char*
af_print_idx( char* p,
int idx )
{
if ( idx == -1 )
{
p[0] = '-';
p[1] = '-';
p[2] = '\0';
}
else
ft_sprintf( p, "%d", idx );
return p;
}
static int
af_get_segment_index( AF_GlyphHints hints,
int point_idx,
int dimension )
{
AF_AxisHints axis = &hints->axis[dimension];
AF_Point point = hints->points + point_idx;
AF_Segment segments = axis->segments;
AF_Segment limit = segments + axis->num_segments;
AF_Segment segment;
for ( segment = segments; segment < limit; segment++ )
{
if ( segment->first <= segment->last )
{
if ( point >= segment->first && point <= segment->last )
break;
}
else
{
AF_Point p = segment->first;
for (;;)
{
if ( point == p )
goto Exit;
if ( p == segment->last )
break;
p = p->next;
}
}
}
Exit:
if ( segment == limit )
return -1;
return (int)( segment - segments );
}
static int
af_get_edge_index( AF_GlyphHints hints,
int segment_idx,
int dimension )
{
AF_AxisHints axis = &hints->axis[dimension];
AF_Edge edges = axis->edges;
AF_Segment segment = axis->segments + segment_idx;
return segment_idx == -1 ? -1 : AF_INDEX_NUM( segment->edge, edges );
}
static int
af_get_strong_edge_index( AF_GlyphHints hints,
AF_Edge* strong_edges,
int dimension )
{
AF_AxisHints axis = &hints->axis[dimension];
AF_Edge edges = axis->edges;
return AF_INDEX_NUM( strong_edges[dimension], edges );
}
#ifdef __cplusplus
extern "C" {
#endif
void
af_glyph_hints_dump_points( AF_GlyphHints hints,
FT_Bool to_stdout )
{
AF_Point points = hints->points;
AF_Point limit = points + hints->num_points;
AF_Point* contour = hints->contours;
AF_Point* climit = contour + hints->num_contours;
AF_Point point;
AF_DUMP(( "Table of points:\n" ));
if ( hints->num_points )
{
AF_DUMP(( " index hedge hseg vedge vseg flags "
/* " XXXXX XXXXX XXXXX XXXXX XXXXX XXXXXX" */
" xorg yorg xscale yscale xfit yfit "
/* " XXXXX XXXXX XXXX.XX XXXX.XX XXXX.XX XXXX.XX" */
" hbef haft vbef vaft" ));
/* " XXXXX XXXXX XXXXX XXXXX" */
}
else
AF_DUMP(( " (none)\n" ));
for ( point = points; point < limit; point++ )
{
int point_idx = AF_INDEX_NUM( point, points );
int segment_idx_0 = af_get_segment_index( hints, point_idx, 0 );
int segment_idx_1 = af_get_segment_index( hints, point_idx, 1 );
char buf1[16], buf2[16], buf3[16], buf4[16];
char buf5[16], buf6[16], buf7[16], buf8[16];
/* insert extra newline at the beginning of a contour */
if ( contour < climit && *contour == point )
{
AF_DUMP(( "\n" ));
contour++;
}
AF_DUMP(( " %5d %5s %5s %5s %5s %s"
" %5d %5d %7.2f %7.2f %7.2f %7.2f"
" %5s %5s %5s %5s\n",
point_idx,
af_print_idx( buf1,
af_get_edge_index( hints, segment_idx_1, 1 ) ),
af_print_idx( buf2, segment_idx_1 ),
af_print_idx( buf3,
af_get_edge_index( hints, segment_idx_0, 0 ) ),
af_print_idx( buf4, segment_idx_0 ),
( point->flags & AF_FLAG_NEAR )
? " near "
: ( point->flags & AF_FLAG_WEAK_INTERPOLATION )
? " weak "
: "strong",
point->fx,
point->fy,
point->ox / 64.0,
point->oy / 64.0,
point->x / 64.0,
point->y / 64.0,
af_print_idx( buf5, af_get_strong_edge_index( hints,
point->before,
1 ) ),
af_print_idx( buf6, af_get_strong_edge_index( hints,
point->after,
1 ) ),
af_print_idx( buf7, af_get_strong_edge_index( hints,
point->before,
0 ) ),
af_print_idx( buf8, af_get_strong_edge_index( hints,
point->after,
0 ) ) ));
}
AF_DUMP(( "\n" ));
}
#ifdef __cplusplus
}
#endif
static const char*
af_edge_flags_to_string( FT_UInt flags )
{
static char temp[32];
int pos = 0;
if ( flags & AF_EDGE_ROUND )
{
ft_memcpy( temp + pos, "round", 5 );
pos += 5;
}
if ( flags & AF_EDGE_SERIF )
{
if ( pos > 0 )
temp[pos++] = ' ';
ft_memcpy( temp + pos, "serif", 5 );
pos += 5;
}
if ( pos == 0 )
return "normal";
temp[pos] = '\0';
return temp;
}
/* Dump the array of linked segments. */
#ifdef __cplusplus
extern "C" {
#endif
void
af_glyph_hints_dump_segments( AF_GlyphHints hints,
FT_Bool to_stdout )
{
FT_Int dimension;
for ( dimension = 1; dimension >= 0; dimension-- )
{
AF_AxisHints axis = &hints->axis[dimension];
AF_Point points = hints->points;
AF_Edge edges = axis->edges;
AF_Segment segments = axis->segments;
AF_Segment limit = segments + axis->num_segments;
AF_Segment seg;
char buf1[16], buf2[16], buf3[16];
AF_DUMP(( "Table of %s segments:\n",
dimension == AF_DIMENSION_HORZ ? "vertical"
: "horizontal" ));
if ( axis->num_segments )
{
AF_DUMP(( " index pos delta dir from to "
/* " XXXXX XXXXX XXXXX XXXXX XXXX XXXX" */
" link serif edge"
/* " XXXX XXXXX XXXX" */
" height extra flags\n" ));
/* " XXXXXX XXXXX XXXXXXXXXXX" */
}
else
AF_DUMP(( " (none)\n" ));
for ( seg = segments; seg < limit; seg++ )
AF_DUMP(( " %5d %5d %5d %5s %4d %4d"
" %4s %5s %4s"
" %6d %5d %11s\n",
AF_INDEX_NUM( seg, segments ),
seg->pos,
seg->delta,
af_dir_str( (AF_Direction)seg->dir ),
AF_INDEX_NUM( seg->first, points ),
AF_INDEX_NUM( seg->last, points ),
af_print_idx( buf1, AF_INDEX_NUM( seg->link, segments ) ),
af_print_idx( buf2, AF_INDEX_NUM( seg->serif, segments ) ),
af_print_idx( buf3, AF_INDEX_NUM( seg->edge, edges ) ),
seg->height,
seg->height - ( seg->max_coord - seg->min_coord ),
af_edge_flags_to_string( seg->flags ) ));
AF_DUMP(( "\n" ));
}
}
#ifdef __cplusplus
}
#endif
/* Fetch number of segments. */
#ifdef __cplusplus
extern "C" {
#endif
FT_Error
af_glyph_hints_get_num_segments( AF_GlyphHints hints,
FT_Int dimension,
FT_Int* num_segments )
{
AF_Dimension dim;
AF_AxisHints axis;
dim = ( dimension == 0 ) ? AF_DIMENSION_HORZ : AF_DIMENSION_VERT;
axis = &hints->axis[dim];
*num_segments = axis->num_segments;
return FT_Err_Ok;
}
#ifdef __cplusplus
}
#endif
/* Fetch offset of segments into user supplied offset array. */
#ifdef __cplusplus
extern "C" {
#endif
FT_Error
af_glyph_hints_get_segment_offset( AF_GlyphHints hints,
FT_Int dimension,
FT_Int idx,
FT_Pos *offset,
FT_Bool *is_blue,
FT_Pos *blue_offset )
{
AF_Dimension dim;
AF_AxisHints axis;
AF_Segment seg;
if ( !offset )
return FT_THROW( Invalid_Argument );
dim = ( dimension == 0 ) ? AF_DIMENSION_HORZ : AF_DIMENSION_VERT;
axis = &hints->axis[dim];
if ( idx < 0 || idx >= axis->num_segments )
return FT_THROW( Invalid_Argument );
seg = &axis->segments[idx];
*offset = ( dim == AF_DIMENSION_HORZ ) ? seg->first->fx
: seg->first->fy;
if ( seg->edge )
*is_blue = FT_BOOL( seg->edge->blue_edge );
else
*is_blue = FALSE;
if ( *is_blue )
*blue_offset = seg->edge->blue_edge->org;
else
*blue_offset = 0;
return FT_Err_Ok;
}
#ifdef __cplusplus
}
#endif
/* Dump the array of linked edges. */
#ifdef __cplusplus
extern "C" {
#endif
void
af_glyph_hints_dump_edges( AF_GlyphHints hints,
FT_Bool to_stdout )
{
FT_Int dimension;
for ( dimension = 1; dimension >= 0; dimension-- )
{
AF_AxisHints axis = &hints->axis[dimension];
AF_Edge edges = axis->edges;
AF_Edge limit = edges + axis->num_edges;
AF_Edge edge;
char buf1[16], buf2[16];
/*
* note: AF_DIMENSION_HORZ corresponds to _vertical_ edges
* since they have a constant X coordinate.
*/
if ( dimension == AF_DIMENSION_HORZ )
AF_DUMP(( "Table of %s edges (1px=%.2fu, 10u=%.2fpx):\n",
"vertical",
65536.0 * 64.0 / hints->x_scale,
10.0 * hints->x_scale / 65536.0 / 64.0 ));
else
AF_DUMP(( "Table of %s edges (1px=%.2fu, 10u=%.2fpx):\n",
"horizontal",
65536.0 * 64.0 / hints->y_scale,
10.0 * hints->y_scale / 65536.0 / 64.0 ));
if ( axis->num_edges )
{
AF_DUMP(( " index pos dir link serif"
/* " XXXXX XXXX.XX XXXXX XXXX XXXXX" */
" blue opos pos flags\n" ));
/* " X XXXX.XX XXXX.XX XXXXXXXXXXX" */
}
else
AF_DUMP(( " (none)\n" ));
for ( edge = edges; edge < limit; edge++ )
AF_DUMP(( " %5d %7.2f %5s %4s %5s"
" %c %7.2f %7.2f %11s\n",
AF_INDEX_NUM( edge, edges ),
(int)edge->opos / 64.0,
af_dir_str( (AF_Direction)edge->dir ),
af_print_idx( buf1, AF_INDEX_NUM( edge->link, edges ) ),
af_print_idx( buf2, AF_INDEX_NUM( edge->serif, edges ) ),
edge->blue_edge ? 'y' : 'n',
edge->opos / 64.0,
edge->pos / 64.0,
af_edge_flags_to_string( edge->flags ) ));
AF_DUMP(( "\n" ));
}
}
#ifdef __cplusplus
}
#endif
#undef AF_DUMP
#endif /* !FT_DEBUG_AUTOFIT */
/* Compute the direction value of a given vector. */
FT_LOCAL_DEF( AF_Direction )
af_direction_compute( FT_Pos dx,
FT_Pos dy )
{
FT_Pos ll, ss; /* long and short arm lengths */
AF_Direction dir; /* candidate direction */
if ( dy >= dx )
{
if ( dy >= -dx )
{
dir = AF_DIR_UP;
ll = dy;
ss = dx;
}
else
{
dir = AF_DIR_LEFT;
ll = -dx;
ss = dy;
}
}
else /* dy < dx */
{
if ( dy >= -dx )
{
dir = AF_DIR_RIGHT;
ll = dx;
ss = dy;
}
else
{
dir = AF_DIR_DOWN;
ll = -dy;
ss = dx;
}
}
/* return no direction if arm lengths do not differ enough */
/* (value 14 is heuristic, corresponding to approx. 4.1 degrees) */
/* the long arm is never negative */
if ( ll <= 14 * FT_ABS( ss ) )
dir = AF_DIR_NONE;
return dir;
}
FT_LOCAL_DEF( void )
af_glyph_hints_init( AF_GlyphHints hints,
FT_Memory memory )
{
/* no need to initialize the embedded items */
FT_MEM_ZERO( hints, sizeof ( *hints ) - sizeof ( hints->embedded ) );
hints->memory = memory;
}
FT_LOCAL_DEF( void )
af_glyph_hints_done( AF_GlyphHints hints )
{
FT_Memory memory;
int dim;
if ( !( hints && hints->memory ) )
return;
memory = hints->memory;
/*
* note that we don't need to free the segment and edge
* buffers since they are really within the hints->points array
*/
for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ )
{
AF_AxisHints axis = &hints->axis[dim];
axis->num_segments = 0;
axis->max_segments = 0;
if ( axis->segments != axis->embedded.segments )
FT_FREE( axis->segments );
axis->num_edges = 0;
axis->max_edges = 0;
if ( axis->edges != axis->embedded.edges )
FT_FREE( axis->edges );
}
if ( hints->contours != hints->embedded.contours )
FT_FREE( hints->contours );
hints->max_contours = 0;
hints->num_contours = 0;
if ( hints->points != hints->embedded.points )
FT_FREE( hints->points );
hints->max_points = 0;
hints->num_points = 0;
hints->memory = NULL;
}
/* Reset metrics. */
FT_LOCAL_DEF( void )
af_glyph_hints_rescale( AF_GlyphHints hints,
AF_StyleMetrics metrics )
{
hints->metrics = metrics;
hints->scaler_flags = metrics->scaler.flags;
}
/* Recompute all AF_Point in AF_GlyphHints from the definitions */
/* in a source outline. */
FT_LOCAL_DEF( FT_Error )
af_glyph_hints_reload( AF_GlyphHints hints,
FT_Outline* outline )
{
FT_Error error = FT_Err_Ok;
AF_Point points;
FT_UInt old_max, new_max;
FT_Fixed x_scale = hints->x_scale;
FT_Fixed y_scale = hints->y_scale;
FT_Pos x_delta = hints->x_delta;
FT_Pos y_delta = hints->y_delta;
FT_Memory memory = hints->memory;
hints->num_points = 0;
hints->num_contours = 0;
hints->axis[0].num_segments = 0;
hints->axis[0].num_edges = 0;
hints->axis[1].num_segments = 0;
hints->axis[1].num_edges = 0;
/* first of all, reallocate the contours array if necessary */
new_max = (FT_UInt)outline->n_contours;
old_max = (FT_UInt)hints->max_contours;
if ( new_max <= AF_CONTOURS_EMBEDDED )
{
if ( !hints->contours )
{
hints->contours = hints->embedded.contours;
hints->max_contours = AF_CONTOURS_EMBEDDED;
}
}
else if ( new_max > old_max )
{
if ( hints->contours == hints->embedded.contours )
hints->contours = NULL;
new_max = ( new_max + 3 ) & ~3U; /* round up to a multiple of 4 */
if ( FT_RENEW_ARRAY( hints->contours, old_max, new_max ) )
goto Exit;
hints->max_contours = (FT_Int)new_max;
}
/*
* then reallocate the points arrays if necessary --
* note that we reserve two additional point positions, used to
* hint metrics appropriately
*/
new_max = (FT_UInt)( outline->n_points + 2 );
old_max = (FT_UInt)hints->max_points;
if ( new_max <= AF_POINTS_EMBEDDED )
{
if ( !hints->points )
{
hints->points = hints->embedded.points;
hints->max_points = AF_POINTS_EMBEDDED;
}
}
else if ( new_max > old_max )
{
if ( hints->points == hints->embedded.points )
hints->points = NULL;
new_max = ( new_max + 2 + 7 ) & ~7U; /* round up to a multiple of 8 */
if ( FT_RENEW_ARRAY( hints->points, old_max, new_max ) )
goto Exit;
hints->max_points = (FT_Int)new_max;
}
hints->num_points = outline->n_points;
hints->num_contours = outline->n_contours;
/* 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. */
/* */
hints->axis[AF_DIMENSION_HORZ].major_dir = AF_DIR_UP;
hints->axis[AF_DIMENSION_VERT].major_dir = AF_DIR_LEFT;
if ( FT_Outline_Get_Orientation( outline ) == FT_ORIENTATION_POSTSCRIPT )
{
hints->axis[AF_DIMENSION_HORZ].major_dir = AF_DIR_DOWN;
hints->axis[AF_DIMENSION_VERT].major_dir = AF_DIR_RIGHT;
}
hints->x_scale = x_scale;
hints->y_scale = y_scale;
hints->x_delta = x_delta;
hints->y_delta = y_delta;
hints->xmin_delta = 0;
hints->xmax_delta = 0;
points = hints->points;
if ( hints->num_points == 0 )
goto Exit;
{
AF_Point point;
AF_Point point_limit = points + hints->num_points;
/* value 20 in `near_limit' is heuristic */
FT_UInt units_per_em = hints->metrics->scaler.face->units_per_EM;
FT_Int near_limit = 20 * units_per_em / 2048;
/* compute coordinates & Bezier flags, next and prev */
{
FT_Vector* vec = outline->points;
char* tag = outline->tags;
FT_Short endpoint = outline->contours[0];
AF_Point end = points + endpoint;
AF_Point prev = end;
FT_Int contour_index = 0;
for ( point = points; point < point_limit; point++, vec++, tag++ )
{
FT_Pos out_x, out_y;
point->in_dir = (FT_Char)AF_DIR_NONE;
point->out_dir = (FT_Char)AF_DIR_NONE;
point->fx = (FT_Short)vec->x;
point->fy = (FT_Short)vec->y;
point->ox = point->x = FT_MulFix( vec->x, x_scale ) + x_delta;
point->oy = point->y = FT_MulFix( vec->y, y_scale ) + y_delta;
end->fx = (FT_Short)outline->points[endpoint].x;
end->fy = (FT_Short)outline->points[endpoint].y;
switch ( FT_CURVE_TAG( *tag ) )
{
case FT_CURVE_TAG_CONIC:
point->flags = AF_FLAG_CONIC;
break;
case FT_CURVE_TAG_CUBIC:
point->flags = AF_FLAG_CUBIC;
break;
default:
point->flags = AF_FLAG_NONE;
}
out_x = point->fx - prev->fx;
out_y = point->fy - prev->fy;
if ( FT_ABS( out_x ) + FT_ABS( out_y ) < near_limit )
prev->flags |= AF_FLAG_NEAR;
point->prev = prev;
prev->next = point;
prev = point;
if ( point == end )
{
if ( ++contour_index < outline->n_contours )
{
endpoint = outline->contours[contour_index];
end = points + endpoint;
prev = end;
}
}
#ifdef FT_DEBUG_AUTOFIT
point->before[0] = NULL;
point->before[1] = NULL;
point->after[0] = NULL;
point->after[1] = NULL;
#endif
}
}
/* set up the contours array */
{
AF_Point* contour = hints->contours;
AF_Point* contour_limit = contour + hints->num_contours;
short* end = outline->contours;
short idx = 0;
for ( ; contour < contour_limit; contour++, end++ )
{
contour[0] = points + idx;
idx = (short)( end[0] + 1 );
}
}
{
/*
* Compute directions of `in' and `out' vectors.
*
* Note that distances between points that are very near to each
* other are accumulated. In other words, the auto-hinter either
* prepends the small vectors between near points to the first
* non-near vector, or the sum of small vector lengths exceeds a
* threshold, thus `grouping' the small vectors. All intermediate
* points are tagged as weak; the directions are adjusted also to
* be equal to the accumulated one.
*/
FT_Int near_limit2 = 2 * near_limit - 1;
AF_Point* contour;
AF_Point* contour_limit = hints->contours + hints->num_contours;
for ( contour = hints->contours; contour < contour_limit; contour++ )
{
AF_Point first = *contour;
AF_Point next, prev, curr;
FT_Pos out_x, out_y;
/* since the first point of a contour could be part of a */
/* series of near points, go backwards to find the first */
/* non-near point and adjust `first' */
point = first;
prev = first->prev;
while ( prev != first )
{
out_x = point->fx - prev->fx;
out_y = point->fy - prev->fy;
/*
* We use Taxicab metrics to measure the vector length.
*
* Note that the accumulated distances so far could have the
* opposite direction of the distance measured here. For this
* reason we use `near_limit2' for the comparison to get a
* non-near point even in the worst case.
*/
if ( FT_ABS( out_x ) + FT_ABS( out_y ) >= near_limit2 )
break;
point = prev;
prev = prev->prev;
}
/* adjust first point */
first = point;
/* now loop over all points of the contour to get */
/* `in' and `out' vector directions */
curr = first;
/*
* We abuse the `u' and `v' fields to store index deltas to the
* next and previous non-near point, respectively.
*
* To avoid problems with not having non-near points, we point to
* `first' by default as the next non-near point.
*
*/
curr->u = (FT_Pos)( first - curr );
first->v = -curr->u;
out_x = 0;
out_y = 0;
next = first;
do
{
AF_Direction out_dir;
point = next;
next = point->next;
out_x += next->fx - point->fx;
out_y += next->fy - point->fy;
if ( FT_ABS( out_x ) + FT_ABS( out_y ) < near_limit )
{
next->flags |= AF_FLAG_WEAK_INTERPOLATION;
continue;
}
curr->u = (FT_Pos)( next - curr );
next->v = -curr->u;
out_dir = af_direction_compute( out_x, out_y );
/* adjust directions for all points inbetween; */
/* the loop also updates position of `curr' */
curr->out_dir = (FT_Char)out_dir;
for ( curr = curr->next; curr != next; curr = curr->next )
{
curr->in_dir = (FT_Char)out_dir;
curr->out_dir = (FT_Char)out_dir;
}
next->in_dir = (FT_Char)out_dir;
curr->u = (FT_Pos)( first - curr );
first->v = -curr->u;
out_x = 0;
out_y = 0;
} while ( next != first );
}
/*
* The next step is to `simplify' an outline's topology so that we
* can identify local extrema more reliably: A series of
* non-horizontal or non-vertical vectors pointing into the same
* quadrant are handled as a single, long vector. From a
* topological point of the view, the intermediate points are of no
* interest and thus tagged as weak.
*/
for ( point = points; point < point_limit; point++ )
{
if ( point->flags & AF_FLAG_WEAK_INTERPOLATION )
continue;
if ( point->in_dir == AF_DIR_NONE &&
point->out_dir == AF_DIR_NONE )
{
/* check whether both vectors point into the same quadrant */
FT_Pos in_x, in_y;
FT_Pos out_x, out_y;
AF_Point next_u = point + point->u;
AF_Point prev_v = point + point->v;
in_x = point->fx - prev_v->fx;
in_y = point->fy - prev_v->fy;
out_x = next_u->fx - point->fx;
out_y = next_u->fy - point->fy;
if ( ( in_x ^ out_x ) >= 0 && ( in_y ^ out_y ) >= 0 )
{
/* yes, so tag current point as weak */
/* and update index deltas */
point->flags |= AF_FLAG_WEAK_INTERPOLATION;
prev_v->u = (FT_Pos)( next_u - prev_v );
next_u->v = -prev_v->u;
}
}
}
/*
* Finally, check for remaining weak points. Everything else not
* collected in edges so far is then implicitly classified as strong
* points.
*/
for ( point = points; point < point_limit; point++ )
{
if ( point->flags & AF_FLAG_WEAK_INTERPOLATION )
continue;
if ( point->flags & AF_FLAG_CONTROL )
{
/* control points are always weak */
Is_Weak_Point:
point->flags |= AF_FLAG_WEAK_INTERPOLATION;
}
else if ( point->out_dir == point->in_dir )
{
if ( point->out_dir != AF_DIR_NONE )
{
/* current point lies on a horizontal or */
/* vertical segment (but doesn't start or end it) */
goto Is_Weak_Point;
}
{
AF_Point next_u = point + point->u;
AF_Point prev_v = point + point->v;
if ( ft_corner_is_flat( point->fx - prev_v->fx,
point->fy - prev_v->fy,
next_u->fx - point->fx,
next_u->fy - point->fy ) )
{
/* either the `in' or the `out' vector is much more */
/* dominant than the other one, so tag current point */
/* as weak and update index deltas */
prev_v->u = (FT_Pos)( next_u - prev_v );
next_u->v = -prev_v->u;
goto Is_Weak_Point;
}
}
}
else if ( point->in_dir == -point->out_dir )
{
/* current point forms a spike */
goto Is_Weak_Point;
}
}
}
}
Exit:
return error;
}
/* Store the hinted outline in an FT_Outline structure. */
FT_LOCAL_DEF( void )
af_glyph_hints_save( AF_GlyphHints hints,
FT_Outline* outline )
{
AF_Point point = hints->points;
AF_Point limit = point + hints->num_points;
FT_Vector* vec = outline->points;
char* tag = outline->tags;
for ( ; point < limit; point++, vec++, tag++ )
{
vec->x = point->x;
vec->y = point->y;
if ( point->flags & AF_FLAG_CONIC )
tag[0] = FT_CURVE_TAG_CONIC;
else if ( point->flags & AF_FLAG_CUBIC )
tag[0] = FT_CURVE_TAG_CUBIC;
else
tag[0] = FT_CURVE_TAG_ON;
}
}
/****************************************************************
*
* EDGE POINT GRID-FITTING
*
****************************************************************/
/* Align all points of an edge to the same coordinate value, */
/* either horizontally or vertically. */
FT_LOCAL_DEF( void )
af_glyph_hints_align_edge_points( 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_Segment seg;
if ( dim == AF_DIMENSION_HORZ )
{
for ( seg = segments; seg < segment_limit; seg++ )
{
AF_Edge edge = seg->edge;
AF_Point point, first, last;
if ( !edge )
continue;
first = seg->first;
last = seg->last;
point = first;
for (;;)
{
point->x = edge->pos;
point->flags |= AF_FLAG_TOUCH_X;
if ( point == last )
break;
point = point->next;
}
}
}
else
{
for ( seg = segments; seg < segment_limit; seg++ )
{
AF_Edge edge = seg->edge;
AF_Point point, first, last;
if ( !edge )
continue;
first = seg->first;
last = seg->last;
point = first;
for (;;)
{
point->y = edge->pos;
point->flags |= AF_FLAG_TOUCH_Y;
if ( point == last )
break;
point = point->next;
}
}
}
}
/****************************************************************
*
* STRONG POINT INTERPOLATION
*
****************************************************************/
/* Hint the strong points -- this is equivalent to the TrueType `IP' */
/* hinting instruction. */
FT_LOCAL_DEF( void )
af_glyph_hints_align_strong_points( AF_GlyphHints hints,
AF_Dimension dim )
{
AF_Point points = hints->points;
AF_Point point_limit = points + hints->num_points;
AF_AxisHints axis = &hints->axis[dim];
AF_Edge edges = axis->edges;
AF_Edge edge_limit = edges + axis->num_edges;
FT_UInt touch_flag;
if ( dim == AF_DIMENSION_HORZ )
touch_flag = AF_FLAG_TOUCH_X;
else
touch_flag = AF_FLAG_TOUCH_Y;
if ( edges < edge_limit )
{
AF_Point point;
AF_Edge edge;
for ( point = points; point < point_limit; point++ )
{
FT_Pos u, ou, fu; /* point position */
FT_Pos delta;
if ( point->flags & touch_flag )
continue;
/* if this point is candidate to weak interpolation, we */
/* interpolate it after all strong points have been processed */
if ( ( point->flags & AF_FLAG_WEAK_INTERPOLATION ) )
continue;
if ( dim == AF_DIMENSION_VERT )
{
u = point->fy;
ou = point->oy;
}
else
{
u = point->fx;
ou = point->ox;
}
fu = u;
/* is the point before the first edge? */
edge = edges;
delta = edge->fpos - u;
if ( delta >= 0 )
{
u = edge->pos - ( edge->opos - ou );
#ifdef FT_DEBUG_AUTOFIT
point->before[dim] = edge;
point->after[dim] = NULL;
#endif
goto Store_Point;
}
/* is the point after the last edge? */
edge = edge_limit - 1;
delta = u - edge->fpos;
if ( delta >= 0 )
{
u = edge->pos + ( ou - edge->opos );
#ifdef FT_DEBUG_AUTOFIT
point->before[dim] = NULL;
point->after[dim] = edge;
#endif
goto Store_Point;
}
{
FT_PtrDist min, max, mid;
FT_Pos fpos;
/* find enclosing edges */
min = 0;
max = edge_limit - edges;
#if 1
/* for a small number of edges, a linear search is better */
if ( max <= 8 )
{
FT_PtrDist nn;
for ( nn = 0; nn < max; nn++ )
if ( edges[nn].fpos >= u )
break;
if ( edges[nn].fpos == u )
{
u = edges[nn].pos;
goto Store_Point;
}
min = nn;
}
else
#endif
while ( min < max )
{
mid = ( max + min ) >> 1;
edge = edges + mid;
fpos = edge->fpos;
if ( u < fpos )
max = mid;
else if ( u > fpos )
min = mid + 1;
else
{
/* we are on the edge */
u = edge->pos;
#ifdef FT_DEBUG_AUTOFIT
point->before[dim] = NULL;
point->after[dim] = NULL;
#endif
goto Store_Point;
}
}
/* point is not on an edge */
{
AF_Edge before = edges + min - 1;
AF_Edge after = edges + min + 0;
#ifdef FT_DEBUG_AUTOFIT
point->before[dim] = before;
point->after[dim] = after;
#endif
/* assert( before && after && before != after ) */
if ( before->scale == 0 )
before->scale = FT_DivFix( after->pos - before->pos,
after->fpos - before->fpos );
u = before->pos + FT_MulFix( fu - before->fpos,
before->scale );
}
}
Store_Point:
/* save the point position */
if ( dim == AF_DIMENSION_HORZ )
point->x = u;
else
point->y = u;
point->flags |= touch_flag;
}
}
}
/****************************************************************
*
* WEAK POINT INTERPOLATION
*
****************************************************************/
/* Shift the original coordinates of all points between `p1' and */
/* `p2' to get hinted coordinates, using the same difference as */
/* given by `ref'. */
static void
af_iup_shift( AF_Point p1,
AF_Point p2,
AF_Point ref )
{
AF_Point p;
FT_Pos delta = ref->u - ref->v;
if ( delta == 0 )
return;
for ( p = p1; p < ref; p++ )
p->u = p->v + delta;
for ( p = ref + 1; p <= p2; p++ )
p->u = p->v + delta;
}
/* Interpolate the original coordinates of all points between `p1' and */
/* `p2' to get hinted coordinates, using `ref1' and `ref2' as the */
/* reference points. The `u' and `v' members are the current and */
/* original coordinate values, respectively. */
/* */
/* Details can be found in the TrueType bytecode specification. */
static void
af_iup_interp( AF_Point p1,
AF_Point p2,
AF_Point ref1,
AF_Point ref2 )
{
AF_Point p;
FT_Pos u, v1, v2, u1, u2, d1, d2;
if ( p1 > p2 )
return;
if ( ref1->v > ref2->v )
{
p = ref1;
ref1 = ref2;
ref2 = p;
}
v1 = ref1->v;
v2 = ref2->v;
u1 = ref1->u;
u2 = ref2->u;
d1 = u1 - v1;
d2 = u2 - v2;
if ( u1 == u2 || v1 == v2 )
{
for ( p = p1; p <= p2; p++ )
{
u = p->v;
if ( u <= v1 )
u += d1;
else if ( u >= v2 )
u += d2;
else
u = u1;
p->u = u;
}
}
else
{
FT_Fixed scale = FT_DivFix( u2 - u1, v2 - v1 );
for ( p = p1; p <= p2; p++ )
{
u = p->v;
if ( u <= v1 )
u += d1;
else if ( u >= v2 )
u += d2;
else
u = u1 + FT_MulFix( u - v1, scale );
p->u = u;
}
}
}
/* Hint the weak points -- this is equivalent to the TrueType `IUP' */
/* hinting instruction. */
FT_LOCAL_DEF( void )
af_glyph_hints_align_weak_points( AF_GlyphHints hints,
AF_Dimension dim )
{
AF_Point points = hints->points;
AF_Point point_limit = points + hints->num_points;
AF_Point* contour = hints->contours;
AF_Point* contour_limit = contour + hints->num_contours;
FT_UInt touch_flag;
AF_Point point;
AF_Point end_point;
AF_Point first_point;
/* PASS 1: Move segment points to edge positions */
if ( dim == AF_DIMENSION_HORZ )
{
touch_flag = AF_FLAG_TOUCH_X;
for ( point = points; point < point_limit; point++ )
{
point->u = point->x;
point->v = point->ox;
}
}
else
{
touch_flag = AF_FLAG_TOUCH_Y;
for ( point = points; point < point_limit; point++ )
{
point->u = point->y;
point->v = point->oy;
}
}
for ( ; contour < contour_limit; contour++ )
{
AF_Point first_touched, last_touched;
point = *contour;
end_point = point->prev;
first_point = point;
/* find first touched point */
for (;;)
{
if ( point > end_point ) /* no touched point in contour */
goto NextContour;
if ( point->flags & touch_flag )
break;
point++;
}
first_touched = point;
for (;;)
{
FT_ASSERT( point <= end_point &&
( point->flags & touch_flag ) != 0 );
/* skip any touched neighbours */
while ( point < end_point &&
( point[1].flags & touch_flag ) != 0 )
point++;
last_touched = point;
/* find the next touched point, if any */
point++;
for (;;)
{
if ( point > end_point )
goto EndContour;
if ( ( point->flags & touch_flag ) != 0 )
break;
point++;
}
/* interpolate between last_touched and point */
af_iup_interp( last_touched + 1, point - 1,
last_touched, point );
}
EndContour:
/* special case: only one point was touched */
if ( last_touched == first_touched )
af_iup_shift( first_point, end_point, first_touched );
else /* interpolate the last part */
{
if ( last_touched < end_point )
af_iup_interp( last_touched + 1, end_point,
last_touched, first_touched );
if ( first_touched > points )
af_iup_interp( first_point, first_touched - 1,
last_touched, first_touched );
}
NextContour:
;
}
/* now save the interpolated values back to x/y */
if ( dim == AF_DIMENSION_HORZ )
{
for ( point = points; point < point_limit; point++ )
point->x = point->u;
}
else
{
for ( point = points; point < point_limit; point++ )
point->y = point->u;
}
}
#ifdef AF_CONFIG_OPTION_USE_WARPER
/* Apply (small) warp scale and warp delta for given dimension. */
FT_LOCAL_DEF( void )
af_glyph_hints_scale_dim( AF_GlyphHints hints,
AF_Dimension dim,
FT_Fixed scale,
FT_Pos delta )
{
AF_Point points = hints->points;
AF_Point points_limit = points + hints->num_points;
AF_Point point;
if ( dim == AF_DIMENSION_HORZ )
{
for ( point = points; point < points_limit; point++ )
point->x = FT_MulFix( point->fx, scale ) + delta;
}
else
{
for ( point = points; point < points_limit; point++ )
point->y = FT_MulFix( point->fy, scale ) + delta;
}
}
#endif /* AF_CONFIG_OPTION_USE_WARPER */
/* END */