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[kern] Abstract away kerning machine

This commit is contained in:
Behdad Esfahbod 2018-10-08 23:09:48 -04:00
parent fb4f438381
commit 683c3a9533
3 changed files with 90 additions and 52 deletions
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2
src/hb-font.hh
View File

@ -502,8 +502,8 @@ struct hb_font_t
hb_position_t *x, hb_position_t *y)
{
if (likely (HB_DIRECTION_IS_HORIZONTAL (direction))) {
*x = get_glyph_h_kerning (first_glyph, second_glyph);
*y = 0;
*x = get_glyph_h_kerning (first_glyph, second_glyph);
} else {
*x = 0;
*y = get_glyph_v_kerning (first_glyph, second_glyph);

71
src/hb-ot-kern-table.hh
View File

@ -28,6 +28,77 @@
#define HB_OT_KERN_TABLE_HH
#include "hb-open-type.hh"
#include "hb-ot-shape.hh"
#include "hb-ot-layout-gsubgpos.hh"
template <typename Driver>
struct hb_kern_machine_t
{
hb_kern_machine_t (Driver &driver_) : driver (driver_) {}
inline void kern (const hb_ot_shape_plan_t *plan,
hb_font_t *font,
hb_buffer_t *buffer) const
{
if (!plan->kerning_requested) return;
OT::hb_ot_apply_context_t c (1, font, buffer);
hb_mask_t kern_mask = plan->kern_mask;
c.set_lookup_mask (kern_mask);
c.set_lookup_props (OT::LookupFlag::IgnoreMarks);
OT::hb_ot_apply_context_t::skipping_iterator_t &skippy_iter = c.iter_input;
skippy_iter.init (&c);
bool horizontal = HB_DIRECTION_IS_HORIZONTAL (buffer->props.direction);
unsigned int count = buffer->len;
hb_glyph_info_t *info = buffer->info;
hb_glyph_position_t *pos = buffer->pos;
for (unsigned int idx = 0; idx < count;)
{
if (!(info[idx].mask & kern_mask))
{
idx++;
continue;
}
skippy_iter.reset (idx, 1);
if (!skippy_iter.next ())
{
idx++;
continue;
}
unsigned int i = idx;
unsigned int j = skippy_iter.idx;
hb_position_t kern = driver.get_kerning (info[i].codepoint,
info[j].codepoint);
hb_position_t kern1 = kern >> 1;
hb_position_t kern2 = kern - kern1;
if (horizontal)
{
pos[i].x_advance += kern1;
pos[j].x_advance += kern2;
pos[j].x_offset += kern2;
}
else
{
pos[i].y_advance += kern1;
pos[j].y_advance += kern2;
pos[j].y_offset += kern2;
}
buffer->unsafe_to_break (i, j + 1);
idx = skippy_iter.idx;
}
}
Driver &driver;
};
/*
* kern -- Kerning

69
src/hb-ot-shape-fallback.cc
View File

@ -25,7 +25,7 @@
*/
#include "hb-ot-shape-fallback.hh"
#include "hb-ot-layout-gsubgpos.hh"
#include "hb-ot-kern-table.hh"
static unsigned int
recategorize_combining_class (hb_codepoint_t u,
@ -435,67 +435,34 @@ _hb_ot_shape_fallback_position (const hb_ot_shape_plan_t *plan,
}
/* Performs old-style TrueType kerning. */
/* Performs font-assisted kerning. */
void
_hb_ot_shape_fallback_kern (const hb_ot_shape_plan_t *plan,
hb_font_t *font,
hb_buffer_t *buffer)
{
if (!plan->kerning_requested) return;
OT::hb_ot_apply_context_t c (1, font, buffer);
hb_mask_t kern_mask = plan->kern_mask;
c.set_lookup_mask (kern_mask);
c.set_lookup_props (OT::LookupFlag::IgnoreMarks);
OT::hb_ot_apply_context_t::skipping_iterator_t &skippy_iter = c.iter_input;
skippy_iter.init (&c);
unsigned int count = buffer->len;
hb_glyph_info_t *info = buffer->info;
hb_glyph_position_t *pos = buffer->pos;
for (unsigned int idx = 0; idx < count;)
struct driver_t
{
if (!(info[idx].mask & kern_mask))
driver_t (hb_font_t *font_,
hb_buffer_t *buffer) :
font (font_), direction (buffer->props.direction) {}
hb_position_t get_kerning (hb_codepoint_t first, hb_codepoint_t second)
{
idx++;
continue;
hb_position_t kern = 0;
font->get_glyph_kerning_for_direction (first, second,
direction,
&kern, &kern);
return kern;
}
skippy_iter.reset (idx, 1);
if (!skippy_iter.next ())
{
idx++;
continue;
}
hb_font_t *font;
hb_direction_t direction;
} driver (font, buffer);
hb_position_t x_kern, y_kern;
font->get_glyph_kerning_for_direction (info[idx].codepoint,
info[skippy_iter.idx].codepoint,
buffer->props.direction,
&x_kern, &y_kern);
hb_kern_machine_t<driver_t> machine (driver);
if (x_kern)
{
hb_position_t kern1 = x_kern >> 1;
hb_position_t kern2 = x_kern - kern1;
pos[idx].x_advance += kern1;
pos[skippy_iter.idx].x_advance += kern2;
pos[skippy_iter.idx].x_offset += kern2;
buffer->unsafe_to_break (idx, skippy_iter.idx + 1);
}
if (y_kern)
{
hb_position_t kern1 = y_kern >> 1;
hb_position_t kern2 = y_kern - kern1;
pos[idx].y_advance += kern1;
pos[skippy_iter.idx].y_advance += kern2;
pos[skippy_iter.idx].y_offset += kern2;
buffer->unsafe_to_break (idx, skippy_iter.idx + 1);
}
idx = skippy_iter.idx;
}
machine.kern (plan, font, buffer);
}