ref: 89d4e4bd9a4fccd6a40373727ef1f667a3bd8cb2
dir: /src/autohint/ahhint.c/
/***************************************************************************/
/* */
/* ahhint.c */
/* */
/* Glyph hinter (body). */
/* */
/* Copyright 2000-2001, 2002, 2003, 2004 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. */
/* */
/***************************************************************************/
#include <ft2build.h>
#include "ahhint.h"
#include "ahglyph.h"
#include "ahangles.h"
#include "aherrors.h"
#include FT_OUTLINE_H
#define FACE_GLOBALS( face ) ( (AH_Face_Globals)(face)->autohint.data )
#define AH_USE_IUP
#define OPTIM_STEM_SNAP
/*************************************************************************/
/*************************************************************************/
/**** ****/
/**** Hinting routines ****/
/**** ****/
/*************************************************************************/
/*************************************************************************/
/* snap a given width in scaled coordinates to one of the */
/* current standard widths */
static FT_Pos
ah_snap_width( FT_Pos* widths,
FT_Int count,
FT_Pos width )
{
int n;
FT_Pos best = 64 + 32 + 2;
FT_Pos reference = width;
FT_Pos scaled;
for ( n = 0; n < count; n++ )
{
FT_Pos w;
FT_Pos dist;
w = widths[n];
dist = width - w;
if ( dist < 0 )
dist = -dist;
if ( dist < best )
{
best = dist;
reference = w;
}
}
scaled = FT_PIX_ROUND( reference );
if ( width >= reference )
{
if ( width < scaled + 48 )
width = reference;
}
else
{
if ( width > scaled - 48 )
width = reference;
}
return width;
}
/* compute the snapped width of a given stem */
#ifdef FT_CONFIG_CHESTER_SERIF
static FT_Pos
ah_compute_stem_width( AH_Hinter hinter,
int vertical,
FT_Pos width,
AH_Edge_Flags base_flags,
AH_Edge_Flags stem_flags )
{
AH_Globals globals = &hinter->globals->scaled;
FT_Pos dist = width;
FT_Int sign = 0;
if ( dist < 0 )
{
dist = -width;
sign = 1;
}
if ( !hinter->do_stem_adjust )
{
/* leave stem widths unchanged */
}
else if ( ( vertical && !hinter->do_vert_snapping ) ||
( !vertical && !hinter->do_horz_snapping ) )
{
/* smooth hinting process: very lightly quantize the stem width */
/* */
/* leave the widths of serifs alone */
if ( ( stem_flags & AH_EDGE_SERIF ) && vertical && ( dist < 3 * 64 ) )
goto Done_Width;
else if ( ( base_flags & AH_EDGE_ROUND ) )
{
if ( dist < 80 )
dist = 64;
}
else if ( dist < 56 )
dist = 56;
{
FT_Pos delta = dist - globals->stds[vertical];
if ( delta < 0 )
delta = -delta;
if ( delta < 40 )
{
dist = globals->stds[vertical];
if ( dist < 48 )
dist = 48;
goto Done_Width;
}
if ( dist < 3 * 64 )
{
delta = dist & 63;
dist &= -64;
if ( delta < 10 )
dist += delta;
else if ( delta < 32 )
dist += 10;
else if ( delta < 54 )
dist += 54;
else
dist += delta;
}
else
dist = ( dist + 32 ) & ~63;
}
}
else
{
/* strong hinting process: snap the stem width to integer pixels */
/* */
if ( vertical )
{
dist = ah_snap_width( globals->heights, globals->num_heights, dist );
/* in the case of vertical hinting, always round */
/* the stem heights to integer pixels */
if ( dist >= 64 )
dist = ( dist + 16 ) & ~63;
else
dist = 64;
}
else
{
dist = ah_snap_width( globals->widths, globals->num_widths, dist );
if ( hinter->flags & AH_HINTER_MONOCHROME )
{
/* monochrome horizontal hinting: snap widths to integer pixels */
/* with a different threshold */
if ( dist < 64 )
dist = 64;
else
dist = ( dist + 32 ) & ~63;
}
else
{
/* for horizontal anti-aliased hinting, we adopt a more subtle */
/* approach: we strengthen small stems, round stems whose size */
/* is between 1 and 2 pixels to an integer, otherwise nothing */
if ( dist < 48 )
dist = ( dist + 64 ) >> 1;
else if ( dist < 128 )
dist = ( dist + 22 ) & ~63;
else
/* XXX: round otherwise to prevent color fringes in LCD mode */
dist = ( dist + 32 ) & ~63;
}
}
}
Done_Width:
if ( sign )
dist = -dist;
return dist;
}
#else /* !FT_CONFIG_CHESTER_SERIF */
static FT_Pos
ah_compute_stem_width( AH_Hinter hinter,
int vertical,
FT_Pos width )
{
AH_Globals globals = &hinter->globals->scaled;
FT_Pos dist = width;
FT_Int sign = 0;
if ( dist < 0 )
{
dist = -width;
sign = 1;
}
if ( !hinter->do_stem_adjust )
{
/* leave stem widths unchanged */
}
else if ( ( vertical && !hinter->do_vert_snapping ) ||
( !vertical && !hinter->do_horz_snapping ) )
{
/* smooth hinting process: very lightly quantize the stem width */
/* */
if ( dist < 64 )
dist = 64;
{
FT_Pos delta = dist - globals->stds[vertical];
if ( delta < 0 )
delta = -delta;
if ( delta < 40 )
{
dist = globals->stds[vertical];
if ( dist < 48 )
dist = 48;
}
if ( dist < 3 * 64 )
{
delta = dist & 63;
dist &= -64;
if ( delta < 10 )
dist += delta;
else if ( delta < 32 )
dist += 10;
else if ( delta < 54 )
dist += 54;
else
dist += delta;
}
else
dist = ( dist + 32 ) & ~63;
}
}
else
{
/* strong hinting process: snap the stem width to integer pixels */
/* */
if ( vertical )
{
dist = ah_snap_width( globals->heights, globals->num_heights, dist );
/* in the case of vertical hinting, always round */
/* the stem heights to integer pixels */
if ( dist >= 64 )
dist = ( dist + 16 ) & ~63;
else
dist = 64;
}
else
{
dist = ah_snap_width( globals->widths, globals->num_widths, dist );
if ( hinter->flags & AH_HINTER_MONOCHROME )
{
/* monochrome horizontal hinting: snap widths to integer pixels */
/* with a different threshold */
if ( dist < 64 )
dist = 64;
else
dist = ( dist + 32 ) & ~63;
}
else
{
/* for horizontal anti-aliased hinting, we adopt a more subtle */
/* approach: we strengthen small stems, round stems whose size */
/* is between 1 and 2 pixels to an integer, otherwise nothing */
if ( dist < 48 )
dist = ( dist + 64 ) >> 1;
else if ( dist < 128 )
dist = ( dist + 22 ) & ~63;
else
/* XXX: round otherwise to prevent color fringes in LCD mode */
dist = ( dist + 32 ) & ~63;
}
}
}
if ( sign )
dist = -dist;
return dist;
}
#endif /* !FT_CONFIG_CHESTER_SERIF */
/* align one stem edge relative to the previous stem edge */
static void
ah_align_linked_edge( AH_Hinter hinter,
AH_Edge base_edge,
AH_Edge stem_edge,
int vertical )
{
FT_Pos dist = stem_edge->opos - base_edge->opos;
#ifdef FT_CONFIG_CHESTER_SERIF
FT_Pos fitted_width = ah_compute_stem_width( hinter,
vertical,
dist,
base_edge->flags,
stem_edge->flags );
stem_edge->pos = base_edge->pos + fitted_width;
#else
stem_edge->pos = base_edge->pos +
ah_compute_stem_width( hinter, vertical, dist );
#endif
}
static void
ah_align_serif_edge( AH_Hinter hinter,
AH_Edge base,
AH_Edge serif,
int vertical )
{
FT_Pos dist;
FT_Pos sign = 1;
FT_UNUSED( hinter );
FT_UNUSED( vertical );
dist = serif->opos - base->opos;
if ( dist < 0 )
{
dist = -dist;
sign = -1;
}
#if 0
/* do not touch serifs widths! */
if ( base->flags & AH_EDGE_DONE )
{
if ( dist >= 64 )
dist = ( dist + 8 ) & ~63;
else if ( dist <= 32 && !vertical )
dist = ( dist + 33 ) >> 1;
else
dist = 0;
}
#endif
serif->pos = base->pos + sign * dist;
}
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/**** ****/
/**** E D G E H I N T I N G ****/
/**** ****/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
FT_LOCAL_DEF( void )
ah_hinter_hint_edges( AH_Hinter hinter )
{
AH_Edge edges;
AH_Edge edge_limit;
AH_Outline outline = hinter->glyph;
FT_Int dimension;
FT_Int n_edges;
edges = outline->horz_edges;
edge_limit = edges + outline->num_hedges;
for ( dimension = 1; dimension >= 0; dimension-- )
{
AH_Edge edge;
AH_Edge anchor = 0;
int has_serifs = 0;
if ( !hinter->do_horz_hints && !dimension )
goto Next_Dimension;
if ( !hinter->do_vert_hints && dimension )
goto Next_Dimension;
/* we begin by aligning all stems relative to the blue zone */
/* if needed -- that's only for horizontal edges */
if ( dimension )
{
for ( edge = edges; edge < edge_limit; edge++ )
{
FT_Pos* blue;
AH_EdgeRec *edge1, *edge2;
if ( edge->flags & AH_EDGE_DONE )
continue;
blue = edge->blue_edge;
edge1 = 0;
edge2 = edge->link;
if ( blue )
{
edge1 = edge;
}
else if ( edge2 && edge2->blue_edge )
{
blue = edge2->blue_edge;
edge1 = edge2;
edge2 = edge;
}
if ( !edge1 )
continue;
edge1->pos = blue[0];
edge1->flags |= AH_EDGE_DONE;
if ( edge2 && !edge2->blue_edge )
{
ah_align_linked_edge( hinter, edge1, edge2, dimension );
edge2->flags |= AH_EDGE_DONE;
}
if ( !anchor )
anchor = edge;
}
}
/* now we will align all stem edges, trying to maintain the */
/* relative order of stems in the glyph */
for ( edge = edges; edge < edge_limit; edge++ )
{
AH_EdgeRec* edge2;
if ( edge->flags & AH_EDGE_DONE )
continue;
/* skip all non-stem edges */
edge2 = edge->link;
if ( !edge2 )
{
has_serifs++;
continue;
}
/* now align the stem */
/* this should not happen, but it's better to be safe */
if ( edge2->blue_edge || edge2 < edge )
{
ah_align_linked_edge( hinter, edge2, edge, dimension );
edge->flags |= AH_EDGE_DONE;
continue;
}
if ( !anchor )
{
#ifdef FT_CONFIG_CHESTER_STEM
FT_Pos org_len, org_center, cur_len;
FT_Pos cur_pos1, error1, error2, u_off, d_off;
org_len = edge2->opos - edge->opos;
cur_len = ah_compute_stem_width( hinter, dimension, org_len,
edge->flags, edge2->flags );
if ( cur_len <= 64 )
u_off = d_off = 32;
else
{
u_off = 38;
d_off = 26;
}
if ( cur_len < 96 )
{
org_center = edge->opos + ( org_len >> 1 );
cur_pos1 = FT_PIX_ROUND( org_center );
error1 = org_center - ( cur_pos1 - u_off );
if ( error1 < 0 )
error1 = -error1;
error2 = org_center - ( cur_pos1 + d_off );
if ( error2 < 0 )
error2 = -error2;
if ( error1 < error2 )
cur_pos1 -= u_off;
else
cur_pos1 += d_off;
edge->pos = cur_pos1 - cur_len / 2;
edge2->pos = cur_pos1 + cur_len / 2;
}
else
edge->pos = FT_PIX_ROUND( edge->opos );
anchor = edge;
edge->flags |= AH_EDGE_DONE;
ah_align_linked_edge( hinter, edge, edge2, dimension );
#else /* !FT_CONFIG_CHESTER_STEM */
edge->pos = FT_PIX_ROUND( edge->opos );
anchor = edge;
edge->flags |= AH_EDGE_DONE;
ah_align_linked_edge( hinter, edge, edge2, dimension );
#endif /* !FT_CONFIG_CHESTER_STEM */
}
else
{
FT_Pos org_pos, org_len, org_center, cur_len;
FT_Pos cur_pos1, cur_pos2, delta1, delta2;
org_pos = anchor->pos + ( edge->opos - anchor->opos );
org_len = edge2->opos - edge->opos;
org_center = org_pos + ( org_len >> 1 );
#ifdef FT_CONFIG_CHESTER_SERIF
cur_len = ah_compute_stem_width( hinter, dimension, org_len,
edge->flags, edge2->flags );
#else /* !FT_CONFIG_CHESTER_SERIF */
cur_len = ah_compute_stem_width( hinter, dimension, org_len );
#endif /* !FT_CONFIG_CHESTER_SERIF */
#ifdef FT_CONFIG_CHESTER_STEM
if ( cur_len < 96 )
{
FT_Pos u_off, d_off;
cur_pos1 = FT_PIX_ROUND( org_center );
if (cur_len <= 64 )
u_off = d_off = 32;
else
{
u_off = 38;
d_off = 26;
}
delta1 = org_center - ( cur_pos1 - u_off );
if ( delta1 < 0 )
delta1 = -delta1;
delta2 = org_center - ( cur_pos1 + d_off );
if ( delta2 < 0 )
delta2 = -delta2;
if ( delta1 < delta2 )
cur_pos1 -= u_off;
else
cur_pos1 += d_off;
edge->pos = cur_pos1 - cur_len / 2;
edge2->pos = cur_pos1 + cur_len / 2;
}
else
{
org_pos = anchor->pos + ( edge->opos - anchor->opos );
org_len = edge2->opos - edge->opos;
org_center = org_pos + ( org_len >> 1 );
cur_len = ah_compute_stem_width( hinter, dimension, org_len,
edge->flags, edge2->flags );
cur_pos1 = FT_PIX_ROUND( org_pos );
delta1 = ( cur_pos1 + ( cur_len >> 1 ) - org_center );
if ( delta1 < 0 )
delta1 = -delta1;
cur_pos2 = FT_PIX_ROUND( org_pos + org_len ) - cur_len;
delta2 = ( cur_pos2 + ( cur_len >> 1 ) - org_center );
if ( delta2 < 0 )
delta2 = -delta2;
edge->pos = ( delta1 < delta2 ) ? cur_pos1 : cur_pos2;
edge2->pos = edge->pos + cur_len;
}
#else /* !FT_CONFIG_CHESTER_STEM */
cur_pos1 = FT_PIX_ROUND( org_pos );
delta1 = ( cur_pos1 + ( cur_len >> 1 ) - org_center );
if ( delta1 < 0 )
delta1 = -delta1;
cur_pos2 = FT_PIX_ROUND( org_pos + org_len ) - cur_len;
delta2 = ( cur_pos2 + ( cur_len >> 1 ) - org_center );
if ( delta2 < 0 )
delta2 = -delta2;
edge->pos = ( delta1 <= delta2 ) ? cur_pos1 : cur_pos2;
edge2->pos = edge->pos + cur_len;
#endif /* !FT_CONFIG_CHESTER_STEM */
edge->flags |= AH_EDGE_DONE;
edge2->flags |= AH_EDGE_DONE;
if ( edge > edges && edge->pos < edge[-1].pos )
edge->pos = edge[-1].pos;
}
}
/* make sure that lowercase m's maintain their symmetry */
/* In general, lowercase m's have six vertical edges if they are sans */
/* serif, or twelve if they are avec serif. This implementation is */
/* based on that assumption, and seems to work very well with most */
/* faces. However, if for a certain face this assumption is not */
/* true, the m is just rendered like before. In addition, any stem */
/* correction will only be applied to symmetrical glyphs (even if the */
/* glyph is not an m), so the potential for unwanted distortion is */
/* relatively low. */
/* We don't handle horizontal edges since we can't easily assure that */
/* the third (lowest) stem aligns with the base line; it might end up */
/* one pixel higher or lower. */
n_edges = (FT_Int)( edge_limit - edges );
if ( !dimension && ( n_edges == 6 || n_edges == 12 ) )
{
AH_EdgeRec *edge1, *edge2, *edge3;
FT_Pos dist1, dist2, span, delta;
if ( n_edges == 6 )
{
edge1 = edges;
edge2 = edges + 2;
edge3 = edges + 4;
}
else
{
edge1 = edges + 1;
edge2 = edges + 5;
edge3 = edges + 9;
}
dist1 = edge2->opos - edge1->opos;
dist2 = edge3->opos - edge2->opos;
span = dist1 - dist2;
if ( span < 0 )
span = -span;
if ( span < 8 )
{
delta = edge3->pos - ( 2 * edge2->pos - edge1->pos );
edge3->pos -= delta;
if ( edge3->link )
edge3->link->pos -= delta;
/* move the serifs along with the stem */
if ( n_edges == 12 )
{
( edges + 8 )->pos -= delta;
( edges + 11 )->pos -= delta;
}
edge3->flags |= AH_EDGE_DONE;
if ( edge3->link )
edge3->link->flags |= AH_EDGE_DONE;
}
}
if ( !has_serifs )
goto Next_Dimension;
/* now hint the remaining edges (serifs and single) in order */
/* to complete our processing */
for ( edge = edges; edge < edge_limit; edge++ )
{
if ( edge->flags & AH_EDGE_DONE )
continue;
if ( edge->serif )
ah_align_serif_edge( hinter, edge->serif, edge, dimension );
else if ( !anchor )
{
edge->pos = FT_PIX_ROUND( edge->opos );
anchor = edge;
}
else
edge->pos = anchor->pos +
FT_PIX_ROUND( edge->opos - anchor->opos );
edge->flags |= AH_EDGE_DONE;
if ( edge > edges && edge->pos < edge[-1].pos )
edge->pos = edge[-1].pos;
if ( edge + 1 < edge_limit &&
edge[1].flags & AH_EDGE_DONE &&
edge->pos > edge[1].pos )
edge->pos = edge[1].pos;
}
Next_Dimension:
edges = outline->vert_edges;
edge_limit = edges + outline->num_vedges;
}
}
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/**** ****/
/**** P O I N T H I N T I N G ****/
/**** ****/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
static void
ah_hinter_align_edge_points( AH_Hinter hinter )
{
AH_Outline outline = hinter->glyph;
AH_Edge edges;
AH_Edge edge_limit;
FT_Int dimension;
edges = outline->horz_edges;
edge_limit = edges + outline->num_hedges;
for ( dimension = 1; dimension >= 0; dimension-- )
{
AH_Edge edge;
edge = edges;
for ( ; edge < edge_limit; edge++ )
{
/* move the points of each segment */
/* in each edge to the edge's position */
AH_Segment seg = edge->first;
do
{
AH_Point point = seg->first;
for (;;)
{
if ( dimension )
{
point->y = edge->pos;
point->flags |= AH_FLAG_TOUCH_Y;
}
else
{
point->x = edge->pos;
point->flags |= AH_FLAG_TOUCH_X;
}
if ( point == seg->last )
break;
point = point->next;
}
seg = seg->edge_next;
} while ( seg != edge->first );
}
edges = outline->vert_edges;
edge_limit = edges + outline->num_vedges;
}
}
/* hint the strong points -- this is equivalent to the TrueType `IP' */
/* hinting instruction */
static void
ah_hinter_align_strong_points( AH_Hinter hinter )
{
AH_Outline outline = hinter->glyph;
FT_Int dimension;
AH_Edge edges;
AH_Edge edge_limit;
AH_Point points;
AH_Point point_limit;
AH_Flags touch_flag;
points = outline->points;
point_limit = points + outline->num_points;
edges = outline->horz_edges;
edge_limit = edges + outline->num_hedges;
touch_flag = AH_FLAG_TOUCH_Y;
for ( dimension = 1; dimension >= 0; dimension-- )
{
AH_Point point;
AH_Edge edge;
if ( edges < edge_limit )
for ( point = points; point < point_limit; point++ )
{
FT_Pos u, ou, fu; /* point position */
FT_Pos delta;
if ( point->flags & touch_flag )
continue;
#ifndef AH_OPTION_NO_WEAK_INTERPOLATION
/* if this point is candidate to weak interpolation, we will */
/* interpolate it after all strong points have been processed */
if ( ( point->flags & AH_FLAG_WEAK_INTERPOLATION ) &&
!( point->flags & AH_FLAG_INFLECTION ) )
continue;
#endif
if ( dimension )
{
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 );
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 );
goto Store_Point;
}
#if 1
{
FT_UInt min, max, mid;
FT_Pos fpos;
/* find enclosing edges */
min = 0;
max = (FT_UInt)( edge_limit - edges );
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;
goto Store_Point;
}
}
{
AH_Edge before = edges + min - 1;
AH_Edge after = edges + min + 0;
/* 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 );
}
}
#else /* !0 */
/* otherwise, interpolate the point in between */
{
AH_Edge before = 0;
AH_Edge after = 0;
for ( edge = edges; edge < edge_limit; edge++ )
{
if ( u == edge->fpos )
{
u = edge->pos;
goto Store_Point;
}
if ( u < edge->fpos )
break;
before = edge;
}
for ( edge = edge_limit - 1; edge >= edges; edge-- )
{
if ( u == edge->fpos )
{
u = edge->pos;
goto Store_Point;
}
if ( u > edge->fpos )
break;
after = edge;
}
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 );
}
#endif /* !0 */
Store_Point:
/* save the point position */
if ( dimension )
point->y = u;
else
point->x = u;
point->flags |= touch_flag;
}
edges = outline->vert_edges;
edge_limit = edges + outline->num_vedges;
touch_flag = AH_FLAG_TOUCH_X;
}
}
#ifndef AH_OPTION_NO_WEAK_INTERPOLATION
static void
ah_iup_shift( AH_Point p1,
AH_Point p2,
AH_Point ref )
{
AH_Point p;
FT_Pos delta = ref->u - ref->v;
for ( p = p1; p < ref; p++ )
p->u = p->v + delta;
for ( p = ref + 1; p <= p2; p++ )
p->u = p->v + delta;
}
static void
ah_iup_interp( AH_Point p1,
AH_Point p2,
AH_Point ref1,
AH_Point ref2 )
{
AH_Point p;
FT_Pos u;
FT_Pos v1 = ref1->v;
FT_Pos v2 = ref2->v;
FT_Pos d1 = ref1->u - v1;
FT_Pos d2 = ref2->u - v2;
if ( p1 > p2 )
return;
if ( v1 == v2 )
{
for ( p = p1; p <= p2; p++ )
{
u = p->v;
if ( u <= v1 )
u += d1;
else
u += d2;
p->u = u;
}
return;
}
if ( v1 < v2 )
{
for ( p = p1; p <= p2; p++ )
{
u = p->v;
if ( u <= v1 )
u += d1;
else if ( u >= v2 )
u += d2;
else
u = ref1->u + FT_MulDiv( u - v1, ref2->u - ref1->u, v2 - v1 );
p->u = u;
}
}
else
{
for ( p = p1; p <= p2; p++ )
{
u = p->v;
if ( u <= v2 )
u += d2;
else if ( u >= v1 )
u += d1;
else
u = ref1->u + FT_MulDiv( u - v1, ref2->u - ref1->u, v2 - v1 );
p->u = u;
}
}
}
/* interpolate weak points -- this is equivalent to the TrueType `IUP' */
/* hinting instruction */
static void
ah_hinter_align_weak_points( AH_Hinter hinter )
{
AH_Outline outline = hinter->glyph;
FT_Int dimension;
AH_Point points;
AH_Point point_limit;
AH_Point* contour_limit;
AH_Flags touch_flag;
points = outline->points;
point_limit = points + outline->num_points;
/* PASS 1: Move segment points to edge positions */
touch_flag = AH_FLAG_TOUCH_Y;
contour_limit = outline->contours + outline->num_contours;
ah_setup_uv( outline, AH_UV_OY );
for ( dimension = 1; dimension >= 0; dimension-- )
{
AH_Point point;
AH_Point end_point;
AH_Point first_point;
AH_Point* contour;
point = points;
contour = outline->contours;
for ( ; contour < contour_limit; contour++ )
{
point = *contour;
end_point = point->prev;
first_point = point;
while ( point <= end_point && !( point->flags & touch_flag ) )
point++;
if ( point <= end_point )
{
AH_Point first_touched = point;
AH_Point cur_touched = point;
point++;
while ( point <= end_point )
{
if ( point->flags & touch_flag )
{
/* we found two successive touched points; we interpolate */
/* all contour points between them */
ah_iup_interp( cur_touched + 1, point - 1,
cur_touched, point );
cur_touched = point;
}
point++;
}
if ( cur_touched == first_touched )
{
/* this is a special case: only one point was touched in the */
/* contour; we thus simply shift the whole contour */
ah_iup_shift( first_point, end_point, cur_touched );
}
else
{
/* now interpolate after the last touched point to the end */
/* of the contour */
ah_iup_interp( cur_touched + 1, end_point,
cur_touched, first_touched );
/* if the first contour point isn't touched, interpolate */
/* from the contour start to the first touched point */
if ( first_touched > points )
ah_iup_interp( first_point, first_touched - 1,
cur_touched, first_touched );
}
}
}
/* now save the interpolated values back to x/y */
if ( dimension )
{
for ( point = points; point < point_limit; point++ )
point->y = point->u;
touch_flag = AH_FLAG_TOUCH_X;
ah_setup_uv( outline, AH_UV_OX );
}
else
{
for ( point = points; point < point_limit; point++ )
point->x = point->u;
break; /* exit loop */
}
}
}
#endif /* !AH_OPTION_NO_WEAK_INTERPOLATION */
FT_LOCAL_DEF( void )
ah_hinter_align_points( AH_Hinter hinter )
{
ah_hinter_align_edge_points( hinter );
#ifndef AH_OPTION_NO_STRONG_INTERPOLATION
ah_hinter_align_strong_points( hinter );
#endif
#ifndef AH_OPTION_NO_WEAK_INTERPOLATION
ah_hinter_align_weak_points( hinter );
#endif
}
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/**** ****/
/**** H I N T E R O B J E C T M E T H O D S ****/
/**** ****/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/* scale and fit the global metrics */
static void
ah_hinter_scale_globals( AH_Hinter hinter,
FT_Fixed x_scale,
FT_Fixed y_scale )
{
FT_Int n;
AH_Face_Globals globals = hinter->globals;
AH_Globals design = &globals->design;
AH_Globals scaled = &globals->scaled;
/* copy content */
*scaled = *design;
/* scale the standard widths & heights */
for ( n = 0; n < design->num_widths; n++ )
scaled->widths[n] = FT_MulFix( design->widths[n], x_scale );
for ( n = 0; n < design->num_heights; n++ )
scaled->heights[n] = FT_MulFix( design->heights[n], y_scale );
scaled->stds[0] = ( design->num_widths > 0 ) ? scaled->widths[0] : 32000;
scaled->stds[1] = ( design->num_heights > 0 ) ? scaled->heights[0] : 32000;
/* scale the blue zones */
for ( n = 0; n < AH_BLUE_MAX; n++ )
{
FT_Pos delta, delta2;
delta = design->blue_shoots[n] - design->blue_refs[n];
delta2 = delta;
if ( delta < 0 )
delta2 = -delta2;
delta2 = FT_MulFix( delta2, y_scale );
if ( delta2 < 32 )
delta2 = 0;
else if ( delta2 < 64 )
delta2 = 32 + ( ( ( delta2 - 32 ) + 16 ) & ~31 );
else
delta2 = FT_PIX_ROUND( delta2 );
if ( delta < 0 )
delta2 = -delta2;
scaled->blue_refs[n] =
FT_PIX_ROUND( FT_MulFix( design->blue_refs[n], y_scale ) );
scaled->blue_shoots[n] = scaled->blue_refs[n] + delta2;
}
globals->x_scale = x_scale;
globals->y_scale = y_scale;
}
static void
ah_hinter_align( AH_Hinter hinter )
{
ah_hinter_align_edge_points( hinter );
ah_hinter_align_points( hinter );
}
/* finalize a hinter object */
FT_LOCAL_DEF( void )
ah_hinter_done( AH_Hinter hinter )
{
if ( hinter )
{
FT_Memory memory = hinter->memory;
ah_loader_done( hinter->loader );
ah_outline_done( hinter->glyph );
/* note: the `globals' pointer is _not_ owned by the hinter */
/* but by the current face object; we don't need to */
/* release it */
hinter->globals = 0;
hinter->face = 0;
FT_FREE( hinter );
}
}
/* create a new empty hinter object */
FT_LOCAL_DEF( FT_Error )
ah_hinter_new( FT_Library library,
AH_Hinter *ahinter )
{
AH_Hinter hinter = 0;
FT_Memory memory = library->memory;
FT_Error error;
*ahinter = 0;
/* allocate object */
if ( FT_NEW( hinter ) )
goto Exit;
hinter->memory = memory;
hinter->flags = 0;
/* allocate outline and loader */
error = ah_outline_new( memory, &hinter->glyph ) ||
ah_loader_new ( memory, &hinter->loader ) ||
ah_loader_create_extra( hinter->loader );
if ( error )
goto Exit;
*ahinter = hinter;
Exit:
if ( error )
ah_hinter_done( hinter );
return error;
}
/* create a face's autohint globals */
FT_LOCAL_DEF( FT_Error )
ah_hinter_new_face_globals( AH_Hinter hinter,
FT_Face face,
AH_Globals globals )
{
FT_Error error;
FT_Memory memory = hinter->memory;
AH_Face_Globals face_globals;
if ( FT_NEW( face_globals ) )
goto Exit;
hinter->face = face;
hinter->globals = face_globals;
if ( globals )
face_globals->design = *globals;
else
ah_hinter_compute_globals( hinter );
face->autohint.data = face_globals;
face->autohint.finalizer = (FT_Generic_Finalizer)
ah_hinter_done_face_globals;
face_globals->face = face;
Exit:
return error;
}
/* discard a face's autohint globals */
FT_LOCAL_DEF( void )
ah_hinter_done_face_globals( AH_Face_Globals globals )
{
FT_Face face = globals->face;
FT_Memory memory = face->memory;
FT_FREE( globals );
}
static FT_Error
ah_hinter_load( AH_Hinter hinter,
FT_UInt glyph_index,
FT_Int32 load_flags,
FT_UInt depth )
{
FT_Face face = hinter->face;
FT_GlyphSlot slot = face->glyph;
FT_Slot_Internal internal = slot->internal;
FT_Fixed x_scale = hinter->globals->x_scale;
FT_Fixed y_scale = hinter->globals->y_scale;
FT_Error error;
AH_Outline outline = hinter->glyph;
AH_Loader gloader = hinter->loader;
/* load the glyph */
error = FT_Load_Glyph( face, glyph_index, load_flags );
if ( error )
goto Exit;
/* Set `hinter->transformed' after loading with FT_LOAD_NO_RECURSE. */
hinter->transformed = internal->glyph_transformed;
if ( hinter->transformed )
{
FT_Matrix imatrix;
imatrix = internal->glyph_matrix;
hinter->trans_delta = internal->glyph_delta;
hinter->trans_matrix = imatrix;
FT_Matrix_Invert( &imatrix );
FT_Vector_Transform( &hinter->trans_delta, &imatrix );
}
/* set linear horizontal metrics */
slot->linearHoriAdvance = slot->metrics.horiAdvance;
slot->linearVertAdvance = slot->metrics.vertAdvance;
switch ( slot->format )
{
case FT_GLYPH_FORMAT_OUTLINE:
/* translate glyph outline if we need to */
if ( hinter->transformed )
{
FT_UInt n = slot->outline.n_points;
FT_Vector* point = slot->outline.points;
for ( ; n > 0; point++, n-- )
{
point->x += hinter->trans_delta.x;
point->y += hinter->trans_delta.y;
}
}
/* copy the outline points in the loader's current */
/* extra points which is used to keep original glyph coordinates */
error = ah_loader_check_points( gloader, slot->outline.n_points + 4,
slot->outline.n_contours );
if ( error )
goto Exit;
FT_ARRAY_COPY( gloader->current.extra_points, slot->outline.points,
slot->outline.n_points );
FT_ARRAY_COPY( gloader->current.outline.contours, slot->outline.contours,
slot->outline.n_contours );
FT_ARRAY_COPY( gloader->current.outline.tags, slot->outline.tags,
slot->outline.n_points );
gloader->current.outline.n_points = slot->outline.n_points;
gloader->current.outline.n_contours = slot->outline.n_contours;
/* compute original horizontal phantom points, ignoring vertical ones */
hinter->pp1.x = 0;
hinter->pp1.y = 0;
hinter->pp2.x = FT_MulFix( slot->metrics.horiAdvance, x_scale );
hinter->pp2.y = 0;
/* be sure to check for spacing glyphs */
if ( slot->outline.n_points == 0 )
goto Hint_Metrics;
/* now load the slot image into the auto-outline and run the */
/* automatic hinting process */
error = ah_outline_load( outline, x_scale, y_scale, face );
if ( error )
goto Exit;
/* perform feature detection */
ah_outline_detect_features( outline );
if ( hinter->do_vert_hints )
{
ah_outline_compute_blue_edges( outline, hinter->globals );
ah_outline_scale_blue_edges( outline, hinter->globals );
}
/* perform alignment control */
ah_hinter_hint_edges( hinter );
ah_hinter_align( hinter );
/* now save the current outline into the loader's current table */
ah_outline_save( outline, gloader );
/* we now need to hint the metrics according to the change in */
/* width/positioning that occured during the hinting process */
if ( outline->num_vedges > 0 )
{
FT_Pos old_advance, old_rsb, old_lsb, new_lsb, pp1x_uh, pp2x_uh;
AH_Edge edge1 = outline->vert_edges; /* leftmost edge */
AH_Edge edge2 = edge1 +
outline->num_vedges - 1; /* rightmost edge */
old_advance = hinter->pp2.x;
old_rsb = old_advance - edge2->opos;
old_lsb = edge1->opos;
new_lsb = edge1->pos;
/* remember unhinted values to later account for rounding errors */
pp1x_uh = new_lsb - old_lsb;
pp2x_uh = edge2->pos + old_rsb;
/* prefer too much space over too little space for very small sizes */
if ( old_lsb < 24 )
pp1x_uh -= 5;
if ( old_rsb < 24 )
pp2x_uh += 5;
hinter->pp1.x = FT_PIX_ROUND( pp1x_uh );
hinter->pp2.x = FT_PIX_ROUND( pp2x_uh );
slot->metrics.lsb_delta = hinter->pp1.x - pp1x_uh;
slot->metrics.rsb_delta = hinter->pp2.x - pp2x_uh;
#if 0
/* try to fix certain bad advance computations */
if ( hinter->pp2.x + hinter->pp1.x == edge2->pos && old_rsb > 4 )
hinter->pp2.x += 64;
#endif
}
else
{
hinter->pp1.x = ( hinter->pp1.x + 32 ) & -64;
hinter->pp2.x = ( hinter->pp2.x + 32 ) & -64;
}
/* good, we simply add the glyph to our loader's base */
ah_loader_add( gloader );
break;
case FT_GLYPH_FORMAT_COMPOSITE:
{
FT_UInt nn, num_subglyphs = slot->num_subglyphs;
FT_UInt num_base_subgs, start_point;
FT_SubGlyph subglyph;
start_point = gloader->base.outline.n_points;
/* first of all, copy the subglyph descriptors in the glyph loader */
error = ah_loader_check_subglyphs( gloader, num_subglyphs );
if ( error )
goto Exit;
FT_ARRAY_COPY( gloader->current.subglyphs, slot->subglyphs,
num_subglyphs );
gloader->current.num_subglyphs = num_subglyphs;
num_base_subgs = gloader->base.num_subglyphs;
/* now, read each subglyph independently */
for ( nn = 0; nn < num_subglyphs; nn++ )
{
FT_Vector pp1, pp2;
FT_Pos x, y;
FT_UInt num_points, num_new_points, num_base_points;
/* gloader.current.subglyphs can change during glyph loading due */
/* to re-allocation -- we must recompute the current subglyph on */
/* each iteration */
subglyph = gloader->base.subglyphs + num_base_subgs + nn;
pp1 = hinter->pp1;
pp2 = hinter->pp2;
num_base_points = gloader->base.outline.n_points;
error = ah_hinter_load( hinter, subglyph->index,
load_flags, depth + 1 );
if ( error )
goto Exit;
/* recompute subglyph pointer */
subglyph = gloader->base.subglyphs + num_base_subgs + nn;
if ( subglyph->flags & FT_SUBGLYPH_FLAG_USE_MY_METRICS )
{
pp1 = hinter->pp1;
pp2 = hinter->pp2;
}
else
{
hinter->pp1 = pp1;
hinter->pp2 = pp2;
}
num_points = gloader->base.outline.n_points;
num_new_points = num_points - num_base_points;
/* now perform the transform required for this subglyph */
if ( subglyph->flags & ( FT_SUBGLYPH_FLAG_SCALE |
FT_SUBGLYPH_FLAG_XY_SCALE |
FT_SUBGLYPH_FLAG_2X2 ) )
{
FT_Vector* cur = gloader->base.outline.points +
num_base_points;
FT_Vector* org = gloader->base.extra_points +
num_base_points;
FT_Vector* limit = cur + num_new_points;
for ( ; cur < limit; cur++, org++ )
{
FT_Vector_Transform( cur, &subglyph->transform );
FT_Vector_Transform( org, &subglyph->transform );
}
}
/* apply offset */
if ( !( subglyph->flags & FT_SUBGLYPH_FLAG_ARGS_ARE_XY_VALUES ) )
{
FT_Int k = subglyph->arg1;
FT_UInt l = subglyph->arg2;
FT_Vector* p1;
FT_Vector* p2;
if ( start_point + k >= num_base_points ||
l >= (FT_UInt)num_new_points )
{
error = AH_Err_Invalid_Composite;
goto Exit;
}
l += num_base_points;
/* for now, only use the current point coordinates; */
/* we may consider another approach in the near future */
p1 = gloader->base.outline.points + start_point + k;
p2 = gloader->base.outline.points + start_point + l;
x = p1->x - p2->x;
y = p1->y - p2->y;
}
else
{
x = FT_MulFix( subglyph->arg1, x_scale );
y = FT_MulFix( subglyph->arg2, y_scale );
x = FT_PIX_ROUND(x);
y = FT_PIX_ROUND(y);
}
{
FT_Outline dummy = gloader->base.outline;
dummy.points += num_base_points;
dummy.n_points = (short)num_new_points;
FT_Outline_Translate( &dummy, x, y );
}
}
}
break;
default:
/* we don't support other formats (yet?) */
error = AH_Err_Unimplemented_Feature;
}
Hint_Metrics:
if ( depth == 0 )
{
FT_BBox bbox;
/* transform the hinted outline if needed */
if ( hinter->transformed )
FT_Outline_Transform( &gloader->base.outline, &hinter->trans_matrix );
/* we must translate our final outline by -pp1.x and compute */
/* the new metrics */
if ( hinter->pp1.x )
FT_Outline_Translate( &gloader->base.outline, -hinter->pp1.x, 0 );
FT_Outline_Get_CBox( &gloader->base.outline, &bbox );
bbox.xMin = FT_PIX_FLOOR( bbox.xMin );
bbox.yMin = FT_PIX_FLOOR( bbox.yMin );
bbox.xMax = FT_PIX_CEIL( bbox.xMax );
bbox.yMax = FT_PIX_CEIL( bbox.yMax );
slot->metrics.width = bbox.xMax - bbox.xMin;
slot->metrics.height = bbox.yMax - bbox.yMin;
slot->metrics.horiBearingX = bbox.xMin;
slot->metrics.horiBearingY = bbox.yMax;
/* for mono-width fonts (like Andale, Courier, etc.) we need */
/* to keep the original rounded advance width */
if ( !FT_IS_FIXED_WIDTH( slot->face ) )
slot->metrics.horiAdvance = hinter->pp2.x - hinter->pp1.x;
else
slot->metrics.horiAdvance = FT_MulFix( slot->metrics.horiAdvance,
x_scale );
slot->metrics.horiAdvance = FT_PIX_ROUND( slot->metrics.horiAdvance );
/* now copy outline into glyph slot */
ah_loader_rewind( slot->internal->loader );
error = ah_loader_copy_points( slot->internal->loader, gloader );
if ( error )
goto Exit;
slot->outline = slot->internal->loader->base.outline;
slot->format = FT_GLYPH_FORMAT_OUTLINE;
}
#ifdef DEBUG_HINTER
ah_debug_hinter = hinter;
#endif
Exit:
return error;
}
/* load and hint a given glyph */
FT_LOCAL_DEF( FT_Error )
ah_hinter_load_glyph( AH_Hinter hinter,
FT_GlyphSlot slot,
FT_Size size,
FT_UInt glyph_index,
FT_Int32 load_flags )
{
FT_Face face = slot->face;
FT_Error error;
FT_Fixed x_scale = size->metrics.x_scale;
FT_Fixed y_scale = size->metrics.y_scale;
AH_Face_Globals face_globals = FACE_GLOBALS( face );
FT_Render_Mode hint_mode = FT_LOAD_TARGET_MODE( load_flags );
/* first of all, we need to check that we're using the correct face and */
/* global hints to load the glyph */
if ( hinter->face != face || hinter->globals != face_globals )
{
hinter->face = face;
if ( !face_globals )
{
error = ah_hinter_new_face_globals( hinter, face, 0 );
if ( error )
goto Exit;
}
hinter->globals = FACE_GLOBALS( face );
face_globals = FACE_GLOBALS( face );
}
#ifdef FT_CONFIG_CHESTER_BLUE_SCALE
/* try to optimize the y_scale so that the top of non-capital letters
* is aligned on a pixel boundary whenever possible
*/
{
AH_Globals design = &face_globals->design;
FT_Pos shoot = design->blue_shoots[AH_BLUE_SMALL_TOP];
/* the value of 'shoot' will be -1000 if the font doesn't have */
/* small latin letters; we simply check the sign here... */
if ( shoot > 0 )
{
FT_Pos scaled = FT_MulFix( shoot, y_scale );
FT_Pos fitted = FT_PIX_ROUND( scaled );
if ( scaled != fitted )
{
/* adjust y_scale
*/
y_scale = FT_MulDiv( y_scale, fitted, scaled );
/* adust x_scale
*/
if ( fitted < scaled )
x_scale -= x_scale / 50; /* x_scale*0.98 with integers */
}
}
}
#endif /* FT_CONFIG_CHESTER_BLUE_SCALE */
/* now, we must check the current character pixel size to see if we */
/* need to rescale the global metrics */
if ( face_globals->x_scale != x_scale ||
face_globals->y_scale != y_scale )
ah_hinter_scale_globals( hinter, x_scale, y_scale );
ah_loader_rewind( hinter->loader );
/* reset hinting flags according to load flags and current render target */
hinter->do_horz_hints = FT_BOOL( !(load_flags & FT_LOAD_NO_AUTOHINT) );
hinter->do_vert_hints = FT_BOOL( !(load_flags & FT_LOAD_NO_AUTOHINT) );
#ifdef DEBUG_HINTER
hinter->do_horz_hints = !ah_debug_disable_vert; /* not a bug, the meaning */
hinter->do_vert_hints = !ah_debug_disable_horz; /* of h/v is inverted! */
#endif
/* we snap the width of vertical stems for the monochrome and */
/* horizontal LCD rendering targets only. Corresponds to X snapping. */
hinter->do_horz_snapping = FT_BOOL( hint_mode == FT_RENDER_MODE_MONO ||
hint_mode == FT_RENDER_MODE_LCD );
/* we snap the width of horizontal stems for the monochrome and */
/* vertical LCD rendering targets only. Corresponds to Y snapping. */
hinter->do_vert_snapping = FT_BOOL( hint_mode == FT_RENDER_MODE_MONO ||
hint_mode == FT_RENDER_MODE_LCD_V );
hinter->do_stem_adjust = FT_BOOL( hint_mode != FT_RENDER_MODE_LIGHT );
load_flags |= FT_LOAD_NO_SCALE
| FT_LOAD_IGNORE_TRANSFORM;
load_flags &= ~FT_LOAD_RENDER;
error = ah_hinter_load( hinter, glyph_index, load_flags, 0 );
Exit:
return error;
}
/* retrieve a face's autohint globals for client applications */
FT_LOCAL_DEF( void )
ah_hinter_get_global_hints( AH_Hinter hinter,
FT_Face face,
void** global_hints,
long* global_len )
{
AH_Globals globals = 0;
FT_Memory memory = hinter->memory;
FT_Error error;
/* allocate new master globals */
if ( FT_NEW( globals ) )
goto Fail;
/* compute face globals if needed */
if ( !FACE_GLOBALS( face ) )
{
error = ah_hinter_new_face_globals( hinter, face, 0 );
if ( error )
goto Fail;
}
*globals = FACE_GLOBALS( face )->design;
*global_hints = globals;
*global_len = sizeof( *globals );
return;
Fail:
FT_FREE( globals );
*global_hints = 0;
*global_len = 0;
}
FT_LOCAL_DEF( void )
ah_hinter_done_global_hints( AH_Hinter hinter,
void* global_hints )
{
FT_Memory memory = hinter->memory;
FT_FREE( global_hints );
}
/* END */