* src/pshinter/pshalgo3.c, src/autohint/ahangles.c,

src/autohint/ahangles.h, src/autohint/ahglyph.c, src/autohint/ahhint.c,
        src/autohint/ahtypes.h: the automatic and Postscript hinter now
        automatically detect inflection points in glyph outlines and treats
        them specially. This is very useful to prevent nasty effect like the
        disappearing diagonals of "S" and "s" in many, many fonts..
This commit is contained in:
David Turner 2002-08-21 21:34:59 +00:00
parent 215bf44438
commit 66456162af
6 changed files with 141 additions and 2 deletions

View File

@ -127,4 +127,20 @@
}
FT_LOCAL_DEF( AH_Angle )
ah_angle_diff( AH_Angle angle1,
AH_Angle angle2 )
{
AH_Angle delta;
delta = ( angle2 - angle1 );
if ( delta < 0 )
delta += AH_2PI;
if ( delta > AH_PI )
delta -= AH_2PI;
return delta;
}
/* END */

View File

@ -51,6 +51,11 @@ FT_BEGIN_HEADER
ah_angle( FT_Vector* v );
FT_LOCAL( AH_Angle )
ah_angle_diff( AH_Angle angle1,
AH_Angle angle2 );
FT_END_HEADER
#endif /* __AHANGLES_H__ */

View File

@ -674,6 +674,120 @@
}
}
/* compute all inflex points in a given glyph */
static void
ah_outline_compute_inflections( AH_Outline* outline )
{
AH_Point** contour = outline->contours;
AH_Point** contour_limit = contour + outline->num_contours;
/* load original coordinates in (u,v) */
ah_setup_uv( outline, ah_uv_fxy );
/* do each contour separately */
for ( ; contour < contour_limit; contour++ )
{
FT_Vector vec;
AH_Point* point = contour[0];
AH_Point* first = point;
AH_Point* start = point;
AH_Point* end = point;
AH_Point* before;
AH_Point* after;
AH_Angle angle_in, angle_seg, angle_out;
AH_Angle diff_in, diff_out;
FT_Int finished = 0;
/* compute first segment in contour */
first = point;
start = end = first;
do
{
end = end->next;
if ( end == first )
goto Skip;
}
while ( end->u == first->u && end->v == first->v );
vec.x = end->u - start->u;
vec.y = end->v - start->v;
angle_seg = ah_angle( &vec );
/* extend the segment start whenever possible */
before = start;
do
{
do
{
start = before;
before = before->prev;
if ( before == first )
goto Skip;
}
while ( before->u == start->u && before->v == start->v );
vec.x = start->u - before->u;
vec.y = start->v - before->v;
angle_in = ah_angle( &vec );
}
while ( angle_in == angle_seg );
first = start;
diff_in = ah_angle_diff( angle_in, angle_seg );
/* now, process all segments in the contour */
do
{
/* first, extend current segment's end whenever possible */
after = end;
do
{
do
{
end = after;
after = after->next;
if ( after == first )
finished = 1;
}
while ( end->u == after->u && end->v == after->v );
vec.x = after->u - end->u;
vec.y = after->v - end->v;
angle_out = ah_angle( &vec );
}
while ( angle_out == angle_seg );
diff_out = ah_angle_diff( angle_seg, angle_out );
if ( diff_in ^ diff_out < 0 )
{
/* diff_in and diff_out have different signs, we have */
/* inflection points here... */
do
{
start->flags |= ah_flag_inflection;
start = start->next;
}
while ( start != end );
start->flags |= ah_flag_inflection;
}
start = end;
end = after;
angle_seg = angle_out;
diff_in = diff_out;
}
while ( !finished );
Skip:
;
}
}
FT_LOCAL_DEF( void )
ah_outline_compute_segments( AH_Outline* outline )
@ -1290,6 +1404,7 @@
ah_outline_compute_segments( outline );
ah_outline_link_segments ( outline );
ah_outline_compute_edges ( outline );
ah_outline_compute_inflections( outline );
}

View File

@ -612,7 +612,8 @@
#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 )
if ( (point->flags & ah_flag_weak_interpolation) &&
!(point->flags & ah_flag_inflection) )
continue;
#endif

View File

@ -147,6 +147,7 @@ FT_BEGIN_HEADER
/* weak interpolation */
#define ah_flag_weak_interpolation 256
#define ah_flag_inflection 512
typedef FT_Int AH_Flags;

View File

@ -1422,7 +1422,8 @@
point->dir_in != point->dir_out )
continue;
if ( !psh3_point_is_extremum( point ) )
if ( !psh3_point_is_extremum( point ) &&
!psh3_point_is_inflection( point ) )
continue;
point->flags &= ~PSH3_POINT_SMOOTH;