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Implement basic loca (long version only) subsetting.

This commit is contained in:
Garret Rieger 2018-02-07 19:01:21 -08:00 committed by Behdad Esfahbod
parent f9c665fed1
commit 8e9fd6f1ab
1 changed files with 46 additions and 20 deletions
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66
src/hb-subset-glyf.cc
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@ -30,36 +30,48 @@
#include "hb-subset-glyf.hh"
bool
_calculate_glyf_prime_size (const OT::glyf::accelerator_t &glyf,
hb_set_t *glyph_ids,
unsigned int *size /* OUT */)
_calculate_glyf_and_loca_prime_size (const OT::glyf::accelerator_t &glyf,
hb_set_t *glyph_ids,
unsigned int *glyf_size /* OUT */,
unsigned int *loca_size /* OUT */)
{
unsigned int total = 0;
unsigned int count = 0;
hb_codepoint_t next_glyph = -1;
while (hb_set_next(glyph_ids, &next_glyph)) {
unsigned int start_offset, end_offset;
if (unlikely (!glyf.get_offsets (next_glyph, &start_offset, &end_offset))) {
*size = 0;
*glyf_size = 0;
*loca_size = sizeof(OT::HBUINT32);
return false;
}
total += end_offset - start_offset;
count++;
}
*size = total;
*glyf_size = total;
*loca_size = (count + 1) * sizeof(OT::HBUINT32);
return true;
}
bool
_write_glyf_prime (const OT::glyf::accelerator_t &glyf,
const char *glyf_data,
hb_set_t *glyph_ids,
int glyf_prime_size,
char *glyf_prime_data /* OUT */)
_write_glyf_and_loca_prime (const OT::glyf::accelerator_t &glyf,
const char *glyf_data,
const hb_set_t *glyph_ids,
int glyf_prime_size,
char *glyf_prime_data /* OUT */,
int loca_prime_size,
char *loca_prime_data /* OUT */)
{
// TODO(grieger): Handle the missing character glyf and outline.
char *glyf_prime_data_next = glyf_prime_data;
OT::HBUINT32 *loca_prime = (OT::HBUINT32*) loca_prime_data;
hb_codepoint_t next_glyph = -1;
hb_codepoint_t new_glyph_id = 0;
while (hb_set_next(glyph_ids, &next_glyph)) {
unsigned int start_offset, end_offset;
if (unlikely (!glyf.get_offsets (next_glyph, &start_offset, &end_offset))) {
@ -68,33 +80,42 @@ _write_glyf_prime (const OT::glyf::accelerator_t &glyf,
int length = end_offset - start_offset;
memcpy (glyf_prime_data_next, glyf_data + start_offset, length);
loca_prime[new_glyph_id].set(start_offset);
glyf_prime_data_next += length;
new_glyph_id++;
}
return true;
}
bool
_hb_subset_glyf (const OT::glyf::accelerator_t &glyf,
const char *glyf_data,
hb_set_t *glyphs_to_retain,
hb_blob_t **glyf_prime /* OUT */)
_hb_subset_glyf_and_loca (const OT::glyf::accelerator_t &glyf,
const char *glyf_data,
hb_set_t *glyphs_to_retain,
hb_blob_t **glyf_prime /* OUT */,
hb_blob_t **loca_prime /* OUT */)
{
// TODO(grieger): Sanity check writes to make sure they are in-bounds.
// TODO(grieger): Sanity check allocation size for the new table.
// TODO(grieger): Subset loca simultaneously.
// TODO(grieger): Don't fail on bad offsets, just dump them.
// TODO(grieger): Support short loca output.
unsigned int glyf_prime_size;
if (unlikely (!_calculate_glyf_prime_size (glyf,
glyphs_to_retain,
&glyf_prime_size))) {
unsigned int loca_prime_size;
if (unlikely (!_calculate_glyf_and_loca_prime_size (glyf,
glyphs_to_retain,
&glyf_prime_size,
&loca_prime_size))) {
return false;
}
char *glyf_prime_data = (char *) calloc (glyf_prime_size, 1);
if (unlikely (!_write_glyf_prime (glyf, glyf_data, glyphs_to_retain, glyf_prime_size,
glyf_prime_data))) {
char *loca_prime_data = (char *) calloc (loca_prime_size, 1);
if (unlikely (!_write_glyf_and_loca_prime (glyf, glyf_data, glyphs_to_retain,
glyf_prime_size, glyf_prime_data,
loca_prime_size, loca_prime_data))) {
free (glyf_prime_data);
return false;
}
@ -104,6 +125,11 @@ _hb_subset_glyf (const OT::glyf::accelerator_t &glyf,
HB_MEMORY_MODE_READONLY,
glyf_prime_data,
free);
*loca_prime = hb_blob_create (loca_prime_data,
loca_prime_size,
HB_MEMORY_MODE_READONLY,
loca_prime_data,
free);
return true;
}
@ -126,7 +152,7 @@ hb_subset_glyf_and_loca (hb_subset_plan_t *plan,
OT::glyf::accelerator_t glyf;
glyf.init(face);
bool result = _hb_subset_glyf (glyf, glyf_data, plan->glyphs_to_retain, glyf_prime);
bool result = _hb_subset_glyf_and_loca (glyf, glyf_data, plan->glyphs_to_retain, glyf_prime, loca_prime);
glyf.fini();
// TODO(grieger): Subset loca