fdo-mirrors/freetype
1
0
Fork 0
mirror of https://gitlab.freedesktop.org/freetype/freetype.git synced 2026-05-05 10:08:12 +02:00
Code Issues Projects Releases Packages Wiki Activity Actions

[autofit] More tilde stretch support. (3/3)

Browse source 
The auto-hinter now supports up to four tilde glyphs (two above and two
below a base character).

Note that diacritics above (or below) a tilde are now also ignored by the
auto-hinter.

* src/autofit/afadjust.h (AF_ADJUST_TILDE_TOP2, AF_ADJUST_TILDE_BOTTOM2):
  New macros.
* src/autofit/afadjust.c (af_reverse_character_map_new): Updated.

* src/autofit/aflatin.c (af_remove_top_points_from_edges,
  af_remove_bottom_points_from_edges): Make functions also handle all
  contours higher (or lower) of the given one in the argument.
  (af_touch_top_contours, af_touch_bottom_contours): New functions.
  (af_latin_stretch_top_tilde, af_latin_stretch_bottom_tilde): Use it to
  also handle all contours higher (or lower) than the tilde contour.

* (af_latin_hints_apply): Handle more tilde glyphs.
This commit is contained in:
Werner Lemberg 2025-04-25 12:28:18 +02:00
parent c6b45a7646
commit 9eb6548d3d
3 changed files with 167 additions and 25 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

6
src/autofit/afadjust.c
View file

@ -678,8 +678,10 @@
const char* flag_names[] =
{
"up", /* AF_ADJUST_UP */
"down", /* AF_ADJUST_DOWN */
"up", /* AF_ADJUST_UP */
"down", /* AF_ADJUST_DOWN */
"double up", /* AF_ADJUST_UP2 */
"double down", /* AF_ADJUST_DOWN2 */
"",
"",
"top tilde", /* AF_ADJUST_TILDE_TOP */

10
src/autofit/afadjust.h
View file

@ -68,6 +68,16 @@ FT_BEGIN_HEADER
/* stays legible at small sizes, not degenerating to a horizontal line. */
#define AF_ADJUST_TILDE_BOTTOM 0x20
/* The contour below the topmost contour is a tilde. Enlarge it */
/* vertically so that it stays legible at small sizes, not degenerating */
/* to a horizontal line. */
#define AF_ADJUST_TILDE_TOP2 0x40
/* The contour above the bottommost contour is a tilde. Enlarge it */
/* vertically so that it stays legible at small sizes, not degenerating */
/* to a horizontal line. */
#define AF_ADJUST_TILDE_BOTTOM2 0x80
/* No adjustment, i.e., no flag is set. */
#define AF_ADJUST_NONE 0x00

176
src/autofit/aflatin.c
View file

@ -3072,38 +3072,71 @@
}
/* Remove all segments containing points on `contour`. */
/* Remove all segments containing points on `limit_contour` */
/* and all higher contours. */
static void
af_remove_top_points_from_edges( AF_GlyphHints hints,
FT_Int contour )
FT_Int limit_contour )
{
AF_Point first_point = hints->contours[contour];
AF_Point p = first_point;
FT_Pos limit = hints->contour_y_minima[limit_contour];
FT_Int contour;
do
for ( contour = 0; contour < hints->num_contours; contour++ )
{
p = p->next;
af_remove_segments_containing_point( hints, p );
FT_Pos min_y = hints->contour_y_minima[contour];
FT_Pos max_y = hints->contour_y_maxima[contour];
} while ( p != first_point );
if ( min_y < max_y &&
min_y >= limit )
{
AF_Point first_point = hints->contours[contour];
AF_Point p = first_point;
do
{
p = p->next;
af_remove_segments_containing_point( hints, p );
} while ( p != first_point );
}
}
}
static void
af_remove_bottom_points_from_edges( AF_GlyphHints hints,
FT_Int contour )
FT_Int limit_contour )
{
AF_Point first_point = hints->contours[contour];
AF_Point p = first_point;
FT_Pos limit = hints->contour_y_maxima[limit_contour];
FT_Int contour;
do
for ( contour = 0; contour < hints->num_contours; contour++ )
{
p = p->next;
af_remove_segments_containing_point( hints, p );
FT_Pos min_y = hints->contour_y_minima[contour];
FT_Pos max_y = hints->contour_y_maxima[contour];
} while ( p != first_point );
if ( min_y < max_y &&
max_y <= limit )
{
AF_Point first_point = hints->contours[contour];
AF_Point p = first_point;
do
{
p = p->next;
af_remove_segments_containing_point( hints, p );
} while ( p != first_point );
}
}
}
@ -3125,6 +3158,50 @@
}
static void
af_touch_top_contours( AF_GlyphHints hints,
FT_Int limit_contour )
{
FT_Pos limit = hints->contour_y_minima[limit_contour];
FT_Int contour;
for ( contour = 0; contour < hints->num_contours; contour++ )
{
FT_Pos min_y = hints->contour_y_minima[contour];
FT_Pos max_y = hints->contour_y_maxima[contour];
if ( min_y < max_y &&
min_y >= limit )
af_touch_contour( hints, contour );
}
}
static void
af_touch_bottom_contours( AF_GlyphHints hints,
FT_Int limit_contour )
{
FT_Pos limit = hints->contour_y_minima[limit_contour];
FT_Int contour;
for ( contour = 0; contour < hints->num_contours; contour++ )
{
FT_Pos min_y = hints->contour_y_minima[contour];
FT_Pos max_y = hints->contour_y_maxima[contour];
if ( min_y < max_y &&
max_y <= limit )
af_touch_contour( hints, contour );
}
}
/* Stretch tilde vertically, if necessary, and return the height */
/* difference between the original and the stretched outline. */
static FT_Pos
@ -3211,9 +3288,14 @@
min_measurement ));
/* To preserve the stretched shape we suppress any */
/* auto-hinting if the tilde height is less than 4 pixels. */
/* auto-hinting if the tilde height is less than 4 pixels; */
/* we do this for all contours equal or above the vertical */
/* minimum of `tilde_contour`. */
/* */
/* The second part is to remove the affected points from */
/* edges, done in `af_latin_hints_apply`. */
if ( height < 64 * 4 )
af_touch_contour( hints, tilde_contour );
af_touch_top_contours( hints, tilde_contour );
/* XXX This is an important element of the algorithm; */
/* we need a description. */
@ -3308,7 +3390,7 @@
min_measurement ));
if ( height < 64 * 4 )
af_touch_contour( hints, tilde_contour );
af_touch_bottom_contours( hints, tilde_contour );
target_height = min_measurement + 64;
if ( height >= target_height )
@ -4609,9 +4691,18 @@
FT_Int top_tilde_contour = 0;
FT_Int bottom_tilde_contour = 0;
FT_Int below_top_tilde_contour = 0;
FT_Int above_bottom_tilde_contour = 0;
FT_Bool is_top_tilde = FALSE;
FT_Bool is_bottom_tilde = FALSE;
FT_Bool is_below_top_tilde = FALSE;
FT_Bool is_above_bottom_tilde = FALSE;
FT_Pos limit;
FT_Pos y_offset;
entry = af_reverse_character_map_lookup( metrics->root.reverse_charmap,
glyph_index );
@ -4625,12 +4716,42 @@
{
is_top_tilde = db_entry->flags & AF_ADJUST_TILDE_TOP;
is_bottom_tilde = db_entry->flags & AF_ADJUST_TILDE_BOTTOM;
is_below_top_tilde = db_entry->flags & AF_ADJUST_TILDE_TOP2;
is_above_bottom_tilde = db_entry->flags & AF_ADJUST_TILDE_BOTTOM2;
}
}
if ( is_top_tilde || is_bottom_tilde )
if ( is_top_tilde || is_bottom_tilde ||
is_below_top_tilde || is_above_bottom_tilde )
af_compute_vertical_extrema( hints );
/* Process inner tilde glyphs first. */
if ( is_below_top_tilde )
{
below_top_tilde_contour = af_find_second_highest_contour( hints );
y_offset = af_latin_stretch_top_tilde(
hints, below_top_tilde_contour );
y_offset += af_latin_align_top_tilde(
hints, below_top_tilde_contour );
limit = hints->contour_y_minima[below_top_tilde_contour];
af_move_contours_up( hints, limit, y_offset );
}
if ( is_above_bottom_tilde )
{
above_bottom_tilde_contour = af_find_second_lowest_contour( hints );
y_offset = af_latin_stretch_bottom_tilde(
hints, above_bottom_tilde_contour );
y_offset -= af_latin_align_bottom_tilde(
hints, above_bottom_tilde_contour );
limit = hints->contour_y_maxima[above_bottom_tilde_contour];
af_move_contours_down( hints, limit, y_offset );
}
if ( is_top_tilde )
{
top_tilde_contour = af_find_highest_contour( hints );
@ -4651,10 +4772,19 @@
axis->width_count,
axis->widths,
AF_DIMENSION_VERT );
if ( is_top_tilde )
af_remove_top_points_from_edges( hints, top_tilde_contour );
if ( is_bottom_tilde )
af_remove_bottom_points_from_edges( hints, bottom_tilde_contour );
/* Second part of making everything of a top tilde and above (or */
/* a bottom tilde and below) be ignored by the auto-hinter. */
if ( is_top_tilde || is_below_top_tilde )
af_remove_top_points_from_edges( hints,
is_top_tilde
? top_tilde_contour
: below_top_tilde_contour );
if ( is_bottom_tilde || is_above_bottom_tilde )
af_remove_bottom_points_from_edges( hints,
is_bottom_tilde
? bottom_tilde_contour
: above_bottom_tilde_contour );
if ( error )
goto Exit;