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Correct phantom point generation and MDAP

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* src/sfnt.c (sfnt_interpret_mdrp): Cease applying cvt
cut in, as this is contrary to the specification.
(sfnt_interpret_simple_glyph): Correct typo.
(main): Revise tests.
This commit is contained in:
Po Lu 2023-12-09 11:49:04 +08:00
parent ef732bd208
commit 414301bce1
1 changed files with 32 additions and 35 deletions
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67
src/sfnt.c
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@ -10381,8 +10381,8 @@ sfnt_interpret_mdrp (struct sfnt_interpreter *interpreter,
uint32_t opcode)
{
uint32_t p;
sfnt_f26dot6 distance, delta;
sfnt_f26dot6 current_projection, original_projection;
sfnt_f26dot6 distance, applied;
sfnt_f26dot6 current_projection;
sfnt_f26dot6 x, y, org_x, org_y;
sfnt_f26dot6 rx, ry, org_rx, org_ry;
@ -10394,20 +10394,21 @@ sfnt_interpret_mdrp (struct sfnt_interpreter *interpreter,
sfnt_address_zp0 (interpreter, interpreter->state.rp0,
&rx, &ry, &org_rx, &org_ry);
/* Calculate the distance between P and rp0 prior to hinting. */
distance = DUAL_PROJECT (org_x - org_rx,
org_y - org_ry);
original_projection = distance;
/* Calculate the distance between P and rp0 as of now in the hinting
process. */
current_projection = PROJECT (x - rx, y - ry);
/* Test against the single width value. */
delta = sfnt_sub (distance,
interpreter->state.single_width_value);
if (delta < 0)
delta = -delta;
if (delta < interpreter->state.sw_cut_in)
if (interpreter->state.sw_cut_in > 0
&& distance < (interpreter->state.single_width_value
+ interpreter->state.sw_cut_in)
&& distance > (interpreter->state.single_width_value
- interpreter->state.sw_cut_in))
{
/* Use the single width instead, as the CVT entry is too
small. */
@ -10418,38 +10419,34 @@ sfnt_interpret_mdrp (struct sfnt_interpreter *interpreter,
distance = -interpreter->state.single_width_value;
}
/* Flag B means look at the cvt cut in and round the
distance. */
/* Flag B implies that the distance should be rounded. The CVT cut
in is not taken into account by MDRP, contrary to earlier
presumptions. */
if (opcode & 4)
{
delta = sfnt_sub (distance, original_projection);
if (delta < 0)
delta = -delta;
if (delta > interpreter->state.cvt_cut_in)
distance = original_projection;
/* Now, round the distance. */
distance = sfnt_round_symmetric (interpreter, distance);
}
applied = sfnt_round_symmetric (interpreter, distance);
else
applied = distance;
/* Flag C means look at the minimum distance. */
if (opcode & 8)
{
if (original_projection >= 0
&& distance < interpreter->state.minimum_distance)
distance = interpreter->state.minimum_distance;
else if (original_projection < 0
&& distance > -interpreter->state.minimum_distance)
distance = -interpreter->state.minimum_distance;
/* Test the sign of the initial distance, but compare the
distance that will be applied in reality against the minimum
distance. */
if (distance >= 0
&& applied < interpreter->state.minimum_distance)
applied = interpreter->state.minimum_distance;
else if (distance < 0
&& applied > -interpreter->state.minimum_distance)
applied = -interpreter->state.minimum_distance;
}
/* Finally, move the point. */
sfnt_move_zp1 (interpreter, p, 1,
sfnt_sub (distance, current_projection));
sfnt_sub (applied, current_projection));
/* Set RP1 to RP0 and RP2 to the point. If flag 3 is set, also make
it RP0. */
@ -11431,8 +11428,8 @@ sfnt_interpret_simple_glyph (struct sfnt_glyph *glyph,
/* Load phantom points. */
zone->y_points[i] = phantom_point_1_y;
zone->y_points[i + 1] = phantom_point_2_y;
zone->y_current[i] = phantom_point_1_x;
zone->y_current[i + 1] = phantom_point_2_x;
zone->y_current[i] = phantom_point_1_y;
zone->y_current[i + 1] = phantom_point_2_y;
/* Load phantom point flags. */
zone->flags[i] = SFNT_POINT_PHANTOM;
@ -19549,8 +19546,8 @@ main (int argc, char **argv)
return 1;
}
#define FANCY_PPEM 18
#define EASY_PPEM 18
#define FANCY_PPEM 40
#define EASY_PPEM 40
interpreter = NULL;
head = sfnt_read_head_table (fd, font);