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freetype2
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Code Issues 4 Releases Wiki Activity

Improve validation for vertical seperation adjustments, and use new approach for tilde unflattening

This commit is contained in:
Craig White 2023-08-12 22:47:00 -04:00
parent 9a813d0c55
commit fa336db624
2 changed files with 204 additions and 31 deletions
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3
src/autofit/afadjust.c
View File

@ -10,6 +10,9 @@
/*TODO: find out whether capital u/U with accent entries are needed*/
/*the accent won't merge with the rest of the glyph because the accent mark is sitting above empty space*/
/*
All entries in this list must be sorted by unicode codepoint ascending
*/
FT_LOCAL_ARRAY_DEF( AF_AdjustmentDatabaseEntry )
adjustment_database[] =
{

232
src/autofit/aflatin.c
View File

@ -2799,6 +2799,87 @@ af_find_highest_contour( AF_GlyphHints hints ) {
return highest_contour;
}
static void
af_remove_segments_containing_point(AF_GlyphHints hints, AF_Point point)
{
AF_AxisHints axis = &hints->axis[AF_DIMENSION_VERT];
AF_Segment segments = axis->segments;
AF_Segment segment_limit = FT_OFFSET( segments, axis->num_segments );
for ( FT_Int i = 0; i < axis->num_segments; i++ )
{
AF_Segment seg = &segments[i];
FT_Bool remove = 0;
for ( AF_Point p = seg->first; p <= seg->last; p = p->next )
{
if ( p == point )
{
remove = 1;
break;
}
}
if ( remove )
{
FT_TRACE4(("Removing segment %d\n", i));
/* first, check the first and last fields of the edge */
AF_Edge edge = seg->edge;
if ( edge->first == seg && edge->last == seg )
{
/* The edge only consists of the segment to be removed. remove the edge*/
*edge = axis->edges[--axis->num_edges];
}
else
{
if ( edge->first == seg )
{
edge->first = seg->edge_next;
}
if ( edge->last == seg )
{
edge->last = edge->first;
while ( edge->last->edge_next != seg )
{
edge->last = edge->last->edge_next;
}
}
}
/* Now, delete the segment */
*seg = axis->segments[--axis->num_segments];
i--; /* we have to check the new segment at this position */
}
}
}
static void
af_latin_stretch_tildes_step_2( AF_GlyphHints hints,
FT_Int glyph_index,
AF_ReverseCharacterMap reverse_charmap )
{
if (af_lookup_tilde_correction_type(reverse_charmap, glyph_index)) {
FT_Int highest_contour = af_find_highest_contour(hints);
AF_Point first_point = hints->contours[highest_contour];
/* search for any curve tips that are on a y extrema, and delete any
segments that contain this point.*/
AF_Point p = first_point;
do
{
p = p->next;
if ( /*!(p->flags & AF_FLAG_CONTROL)
&& p->prev->y == p->y && p->next->y == p->y
&& p->prev->flags & AF_FLAG_CONTROL
&& p->next->flags & AF_FLAG_CONTROL*/ 1 )
{
af_remove_segments_containing_point( hints, p );
}
} while ( p != first_point );
}
}
void
af_latin_stretch_tildes( AF_GlyphHints hints,
FT_Int glyph_index,
@ -2814,82 +2895,99 @@ af_latin_stretch_tildes( AF_GlyphHints hints,
FT_Short min_fy, max_fy;
min_fy = max_fy = p->fy;
do {
do
{
p = p->next;
if ( p->y < min_y ) {
if ( p->y < min_y )
{
min_y = p->y;
}
if ( p->y > max_y ) {
if ( p->y > max_y )
{
max_y = p->y;
}
if ( p->fy < min_fy ) {
if ( p->fy < min_fy )
{
min_fy = p->fy;
}
if ( p->fy > max_fy ) {
if ( p->fy > max_fy )
{
max_fy = p->fy;
}
} while ( p != first_point );
}
while ( p != first_point );
FT_Pos min_measurement = 32000;
FT_UInt measurements_taken = 0;
do {
do
{
p = p->next;
if ( !(p->flags & AF_FLAG_CONTROL)
&& p->prev->y == p->y && p->next->y == p->y
&& p->y != min_y && p->y != max_y
&& p->prev->flags & AF_FLAG_CONTROL
&& p->next->flags & AF_FLAG_CONTROL ) {
&& p->next->flags & AF_FLAG_CONTROL )
{
/* This point could be a candidate. Find the next and previous on-curve */
/* points, and make sure they are both either above or below the point, */
/* Then make the measurement */
AF_Point prevOn = p->prev;
AF_Point nextOn = p->next;
while ( prevOn->flags & AF_FLAG_CONTROL ) {
while ( prevOn->flags & AF_FLAG_CONTROL )
{
prevOn = prevOn->prev;
}
while ( nextOn->flags & AF_FLAG_CONTROL ) {
while ( nextOn->flags & AF_FLAG_CONTROL )
{
nextOn = nextOn->next;
}
FT_Pos measurement;
if ( nextOn->y > p->y && prevOn->y > p->y ) {
if ( nextOn->y > p->y && prevOn->y > p->y )
{
measurement = p->y - min_y;
} else if ( nextOn->y < p->y && prevOn->y < p->y ) {
}
else if ( nextOn->y < p->y && prevOn->y < p->y )
{
measurement = max_y - p->y;
} else {
}
else
{
continue;
}
if (measurement < min_measurement) {
if (measurement < min_measurement)
{
min_measurement = measurement;
}
measurements_taken++;
}
} while ( p != first_point );
}
while ( p != first_point );
FT_Pos height = max_y - min_y;
FT_Pos target_height = min_measurement + 64;
if ( height >= target_height ) {
if ( height >= target_height )
{
return;
}
p = first_point;
do {
do
{
p = p->next;
/*if ( p->flags & AF_FLAG_CONTROL ) {
continue;
}*/
p->y = ((p->y - min_y) * target_height / height) + min_y;
p->fy = ((p->fy - min_fy) * target_height / height) + min_fy;
p->oy = p->y;
if ( !(p->flags & AF_FLAG_CONTROL) )
p->flags |= AF_FLAG_TOUCH_Y;
} while ( p != first_point );
}
while ( p != first_point );
FT_TRACE4(( "af_latin_stretch_tildes: Height: %d, measurement: %d, measurements taken: %d\n", height, min_measurement, measurements_taken ));
@ -2898,18 +2996,73 @@ af_latin_stretch_tildes( AF_GlyphHints hints,
p = first_point;
do {
p = p->next;
if ( p->y < new_min_y ) {
if ( p->y < new_min_y )
{
new_min_y = p->y;
}
if ( p->y > new_max_y ) {
if ( p->y > new_max_y )
{
new_max_y = p->y;
}
} while ( p != first_point );
}
while ( p != first_point );
FT_TRACE4(( "af_latin_stretch_tildes_merp: New height: %d\n, miny: %d, maxy: %d", new_max_y - new_min_y, new_min_y, new_max_y));
FT_TRACE4(( "af_latin_stretch_tildes: New height: %d\n, miny: %d, maxy: %d", new_max_y - new_min_y, new_min_y, new_max_y));
}
}
/*True if the given contour overlaps horizontally with the bounding box
Of all other contours combined.
This is a helper for af_glyph_hints_apply_vertical_separation_adjustments */
FT_Bool
af_check_contour_horizontal_overlap( AF_GlyphHints hints,
FT_Int contour_index )
{
FT_Pos contour_max_x = -32000;
FT_Pos contour_min_x = 32000;
FT_Pos others_max_x = -32000;
FT_Pos others_min_x = 32000;
for ( FT_Int contour = 0; contour < hints->num_contours; contour++ )
{
AF_Point first_point = hints->contours[contour];
AF_Point p = first_point;
do
{
p = p->next;
if ( contour == contour_index )
{
if ( p->x < contour_min_x )
{
contour_min_x = p->x;
}
if ( p->x > contour_max_x )
{
contour_max_x = p->x;
}
}
else /* ( contour != contour_index ) */
{
if ( p->x < others_min_x )
{
others_min_x = p->x;
}
if ( p->x > others_max_x )
{
others_max_x = p->x;
}
}
}
while (p != first_point);
}
FT_Bool horizontal_overlap =
(others_min_x <= contour_max_x && contour_max_x <= others_max_x) ||
(others_min_x <= contour_min_x && contour_min_x <= others_max_x) ||
(contour_max_x >= others_max_x && contour_min_x <= others_min_x);
return horizontal_overlap;
}
void
@ -2961,6 +3114,15 @@ af_glyph_hints_apply_vertical_separation_adjustments( AF_GlyphHints hints,
}
}
/* check for a horizontal overtap between the top contour and the rest */
/* if there is no overlap, do not adjust. */
FT_Bool horizontal_overlap = af_check_contour_horizontal_overlap( hints, highest_contour );
if (!horizontal_overlap) {
FT_TRACE4(( " Top contour does not horizontally overlap with other contours. Skipping adjustment.\n" ));
return;
}
/* If there are any contours that have a maximum y coordinate */
/* greater or equal to the minimum y coordinate of the previously found highest*/
/* contour, bump the high contour up until the distance is one pixel */
@ -2995,9 +3157,13 @@ af_glyph_hints_apply_vertical_separation_adjustments( AF_GlyphHints hints,
}
}
FT_TRACE4(( " Pushing top contour %d units up\n", adjustment_amount ));
if ( adjustment_amount > 0 )
if ( adjustment_amount > 64 )
{
FT_TRACE4(( " Calculated adjustment amount %d was more than threshold of 64. Not adjusting\n", adjustment_amount ));
}
else if ( adjustment_amount > 0 )
{
FT_TRACE4(( " Pushing top contour %d units up\n", adjustment_amount ));
af_move_contour_vertically(hints->contours[highest_contour], adjustment_amount);
}
} else if ( af_lookup_vertical_seperation_type( reverse_charmap, glyph_index ) == AF_VERTICAL_ADJUSTMENT_BOTTOM_CONTOUR_DOWN
@ -3065,9 +3231,13 @@ af_glyph_hints_apply_vertical_separation_adjustments( AF_GlyphHints hints,
adjustment_amount = 64 - ( min_y - lowest_max_y );
}
FT_TRACE4(( " Pushing bottom contour %d units down\n", adjustment_amount ));
if ( adjustment_amount > 0 )
if ( adjustment_amount > 64 )
{
FT_TRACE4(( " Calculated adjustment amount %d was more than threshold of 64. Not adjusting\n", adjustment_amount ));
}
else if ( adjustment_amount > 0 )
{
FT_TRACE4(( " Pushing bottom contour %d units down\n", adjustment_amount ));
af_move_contour_vertically(hints->contours[lowest_contour], -adjustment_amount);
}
}
@ -3900,7 +4070,6 @@ static void traceheight(FT_UInt num, AF_GlyphHints hints) {
FT_Pos min_y, max_y;
min_y = max_y = p->y;
FT_UInt candidates = 0;
do {
p = p->next;
@ -3952,12 +4121,13 @@ static void traceheight(FT_UInt num, AF_GlyphHints hints) {
if ( AF_HINTS_DO_VERTICAL( hints ) )
{
af_latin_stretch_tildes( hints, glyph_index, metrics->root.reverse_charmap );
/*af_latin_stretch_tildes( hints, glyph_index, metrics->root.reverse_charmap );*/
axis = &metrics->axis[AF_DIMENSION_VERT];
error = af_latin_hints_detect_features( hints,
axis->width_count,
axis->widths,
AF_DIMENSION_VERT );
af_latin_stretch_tildes_step_2( hints, glyph_index, metrics->root.reverse_charmap );
if ( error )
goto Exit;