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[coretext] Unbreak glyph positioning in presence of notdef runs 

As discovered on Chrome Mac:
https://code.google.com/p/chromium/issues/detail?id=452326

This was originally broken in:

	commit 5a0eed3b50
	Author: Behdad Esfahbod <behdad@behdad.org>
	Date:   Mon Aug 11 23:47:16 2014 -0400

	    [coretext] Implement vertical shaping
This commit is contained in:
Behdad Esfahbod 2015-01-28 10:43:32 -08:00
parent 1eff435023
commit 6917a045fd
1 changed files with 27 additions and 8 deletions
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35
src/hb-coretext.cc
View File

@ -787,6 +787,7 @@ retry:
buffer->len = 0;
uint32_t status_and = ~0, status_or = 0;
double advances_so_far = 0;
const CFRange range_all = CFRangeMake (0, 0);
@ -797,6 +798,10 @@ retry:
status_or |= run_status;
status_and &= run_status;
DEBUG_MSG (CORETEXT, run, "CTRunStatus: %x", run_status);
double run_advance = CTRunGetTypographicBounds (run, range_all, NULL, NULL, NULL);
if (HB_DIRECTION_IS_VERTICAL (buffer->props.direction))
run_advance = -run_advance;
DEBUG_MSG (CORETEXT, run, "Run advance: %g", run_advance);
/* CoreText does automatic font fallback (AKA "cascading") for characters
* not supported by the requested font, and provides no way to turn it off,
@ -905,6 +910,7 @@ retry:
}
if (HB_DIRECTION_IS_BACKWARD (buffer->props.direction))
buffer->reverse_range (old_len, buffer->len);
advances_so_far += run_advance;
continue;
}
}
@ -934,7 +940,7 @@ retry:
scratch_size = scratch_size_saved; \
scratch = scratch_saved;
{
{ /* Setup glyphs */
SCRATCH_SAVE();
const CGGlyph* glyphs = USE_PTR ? CTRunGetGlyphsPtr (run) : NULL;
if (!glyphs) {
@ -958,6 +964,11 @@ retry:
SCRATCH_RESTORE();
}
{
/* Setup positions.
* Note that CoreText does not return advances for glyphs. As such,
* for all but last glyph, we use the delta position to next glyph as
* advance (in the advance direction only), and for last glyph we set
* whatever is needed to make the whole run's advance add up. */
SCRATCH_SAVE();
const CGPoint* positions = USE_PTR ? CTRunGetPositionsPtr (run) : NULL;
if (!positions) {
@ -965,34 +976,42 @@ retry:
CTRunGetPositions (run, range_all, position_buf);
positions = position_buf;
}
double run_advance = CTRunGetTypographicBounds (run, range_all, NULL, NULL, NULL);
DEBUG_MSG (CORETEXT, run, "Run advance: %g", run_advance);
hb_glyph_info_t *info = run_info;
CGFloat x_mult = font_data->x_mult, y_mult = font_data->y_mult;
if (HB_DIRECTION_IS_HORIZONTAL (buffer->props.direction))
{
hb_position_t x_offset = (positions[0].x - advances_so_far) * x_mult;
for (unsigned int j = 0; j < num_glyphs; j++)
{
double advance = (j + 1 < num_glyphs ? positions[j + 1].x : positions[0].x + run_advance) - positions[j].x;
double advance;
if (likely (j + 1 < num_glyphs))
advance = positions[j + 1].x - positions[j].x;
else /* last glyph */
advance = run_advance - (positions[j].x - positions[0].x);
info->mask = advance * x_mult;
info->var1.u32 = positions[0].x * x_mult; /* Yes, zero. */
info->var1.u32 = x_offset;
info->var2.u32 = positions[j].y * y_mult;
info++;
}
}
else
{
run_advance = -run_advance;
hb_position_t y_offset = (positions[0].y - advances_so_far) * y_mult;
for (unsigned int j = 0; j < num_glyphs; j++)
{
double advance = (j + 1 < num_glyphs ? positions[j + 1].y : positions[0].y + run_advance) - positions[j].y;
double advance;
if (likely (j + 1 < num_glyphs))
advance = positions[j + 1].y - positions[j].y;
else /* last glyph */
advance = run_advance - (positions[j].y - positions[0].y);
info->mask = advance * y_mult;
info->var1.u32 = positions[j].x * x_mult;
info->var2.u32 = positions[0].y * y_mult; /* Yes, zero. */
info->var2.u32 = y_offset;
info++;
}
}
SCRATCH_RESTORE();
advances_so_far += run_advance;
}
#undef SCRATCH_RESTORE
#undef SCRATCH_SAVE