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When zeroing mark widths for LTR, also adjust offset... 

...so that they overstrike preceding glyph.

https://github.com/behdad/harfbuzz/pull/43
This commit is contained in:
Jonathan Kew 2014-06-10 13:10:30 +01:00 committed by Behdad Esfahbod
parent 80f7405a52
commit 798e4185bc
1 changed files with 39 additions and 11 deletions
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50
src/hb-ot-shape.cc
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@ -452,26 +452,42 @@ hb_ot_substitute (hb_ot_shape_context_t *c)
/* Position */
static inline void
zero_mark_widths_by_unicode (hb_buffer_t *buffer)
adjust_mark_offsets (hb_glyph_position_t *pos)
{
pos->x_offset -= pos->x_advance;
pos->y_offset -= pos->y_advance;
}
static inline void
zero_mark_width (hb_glyph_position_t *pos)
{
pos->x_advance = 0;
pos->y_advance = 0;
}
static inline void
zero_mark_widths_by_unicode (hb_buffer_t *buffer, bool adjust_offsets)
{
unsigned int count = buffer->len;
for (unsigned int i = 0; i < count; i++)
if (_hb_glyph_info_get_general_category (&buffer->info[i]) == HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK)
{
buffer->pos[i].x_advance = 0;
buffer->pos[i].y_advance = 0;
if (adjust_offsets)
adjust_mark_offsets (&buffer->pos[i]);
zero_mark_width (&buffer->pos[i]);
}
}
static inline void
zero_mark_widths_by_gdef (hb_buffer_t *buffer)
zero_mark_widths_by_gdef (hb_buffer_t *buffer, bool adjust_offsets)
{
unsigned int count = buffer->len;
for (unsigned int i = 0; i < count; i++)
if (_hb_glyph_info_is_mark (&buffer->info[i]))
{
buffer->pos[i].x_advance = 0;
buffer->pos[i].y_advance = 0;
if (adjust_offsets)
adjust_mark_offsets (&buffer->pos[i]);
zero_mark_width (&buffer->pos[i]);
}
}
@ -501,16 +517,28 @@ hb_ot_position_complex (hb_ot_shape_context_t *c)
{
bool ret = false;
unsigned int count = c->buffer->len;
bool has_positioning = hb_ot_layout_has_positioning (c->face);
/* If the font has no GPOS, AND, no fallback positioning will
* happen, AND, direction is forward, then when zeroing mark
* widths, we shift the mark with it, such that the mark
* is positioned hanging over the previous glyph. When
* direction is backward we don't shift and it will end up
* hanging over the next glyph after the final reordering.
* If fallback positinoing happens or GPOS is present, we don't
* care.
*/
bool adjust_offsets_when_zeroing = !(has_positioning || c->plan->shaper->fallback_position ||
HB_DIRECTION_IS_BACKWARD (c->buffer->props.direction));
switch (c->plan->shaper->zero_width_marks)
{
case HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_EARLY:
zero_mark_widths_by_gdef (c->buffer);
zero_mark_widths_by_gdef (c->buffer, adjust_offsets_when_zeroing);
break;
/* Not currently used for any shaper:
case HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_UNICODE_EARLY:
zero_mark_widths_by_unicode (c->buffer);
zero_mark_widths_by_unicode (c->buffer, adjust_offsets_when_zeroing);
break;
*/
@ -521,7 +549,7 @@ hb_ot_position_complex (hb_ot_shape_context_t *c)
break;
}
if (hb_ot_layout_has_positioning (c->face))
if (has_positioning)
{
hb_glyph_info_t *info = c->buffer->info;
hb_glyph_position_t *pos = c->buffer->pos;
@ -550,11 +578,11 @@ hb_ot_position_complex (hb_ot_shape_context_t *c)
switch (c->plan->shaper->zero_width_marks)
{
case HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_UNICODE_LATE:
zero_mark_widths_by_unicode (c->buffer);
zero_mark_widths_by_unicode (c->buffer, adjust_offsets_when_zeroing);
break;
case HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE:
zero_mark_widths_by_gdef (c->buffer);
zero_mark_widths_by_gdef (c->buffer, adjust_offsets_when_zeroing);
break;
default: