ref: 66456162afdeef73a7a705f4e94c6ae32f71ebfd
parent: 215bf444380dd706a72c2d1037f827396e735791
author: David Turner <[email protected]>
date: Wed Aug 21 17:34:59 EDT 2002
* 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..
--- a/src/autohint/ahangles.c
+++ b/src/autohint/ahangles.c
@@ -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 */
--- a/src/autohint/ahangles.h
+++ b/src/autohint/ahangles.h
@@ -51,6 +51,11 @@
ah_angle( FT_Vector* v );
+ FT_LOCAL( AH_Angle )
+ ah_angle_diff( AH_Angle angle1,
+ AH_Angle angle2 );
+
+
FT_END_HEADER
#endif /* __AHANGLES_H__ */
--- a/src/autohint/ahglyph.c
+++ b/src/autohint/ahglyph.c
@@ -674,7 +674,121 @@
}
}
+ /* 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 );
}
--- a/src/autohint/ahhint.c
+++ b/src/autohint/ahhint.c
@@ -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
--- a/src/autohint/ahtypes.h
+++ b/src/autohint/ahtypes.h
@@ -147,6 +147,7 @@
/* weak interpolation */
#define ah_flag_weak_interpolation 256
+#define ah_flag_inflection 512
typedef FT_Int AH_Flags;
--- a/src/pshinter/pshalgo3.c
+++ b/src/pshinter/pshalgo3.c
@@ -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;