Re-implement HMTX/VMTX subsetting. Update it to support glyph renumbering and simplify the implementation.
diff --git a/src/hb-ot-hmtx-table.hh b/src/hb-ot-hmtx-table.hh
index a95a56f..c743e08 100644
--- a/src/hb-ot-hmtx-table.hh
+++ b/src/hb-ot-hmtx-table.hh
@@ -66,7 +66,7 @@
bool subset_update_header (hb_subset_plan_t *plan,
- unsigned int num_hmetrics) const
+ unsigned int num_hmetrics) const
{
hb_blob_t *src_blob = hb_sanitize_context_t ().reference_table<H> (plan->source, H::tableTag);
hb_blob_t *dest_blob = hb_blob_copy_writable_or_fail (src_blob);
@@ -93,25 +93,20 @@
/* All the trailing glyphs with the same advance can use one LongMetric
* and just keep LSB */
- hb_vector_t<hb_codepoint_t> &gids = plan->glyphs;
- unsigned int num_advances = gids.length;
- unsigned int last_advance = _mtx.get_advance (gids[num_advances - 1]);
- while (num_advances > 1 &&
- last_advance == _mtx.get_advance (gids[num_advances - 2]))
- {
- num_advances--;
- }
+ unsigned int num_output_glyphs = plan->num_output_glyphs ();
+ unsigned int num_advances = _mtx.num_advances_for_subset (plan);
/* alloc the new table */
size_t dest_sz = num_advances * 4
- + (gids.length - num_advances) * 2;
+ + (num_output_glyphs - num_advances) * 2;
void *dest = (void *) malloc (dest_sz);
if (unlikely (!dest))
{
return false;
}
DEBUG_MSG(SUBSET, nullptr, "%c%c%c%c in src has %d advances, %d lsbs", HB_UNTAG(T::tableTag), _mtx.num_advances, _mtx.num_metrics - _mtx.num_advances);
- DEBUG_MSG(SUBSET, nullptr, "%c%c%c%c in dest has %d advances, %d lsbs, %u bytes", HB_UNTAG(T::tableTag), num_advances, gids.length - num_advances, (unsigned int) dest_sz);
+ DEBUG_MSG(SUBSET, nullptr, "%c%c%c%c in dest has %d advances, %d lsbs, %u bytes",
+ HB_UNTAG(T::tableTag), num_advances, num_output_glyphs - num_advances, (unsigned int) dest_sz);
const char *source_table = hb_blob_get_data (_mtx.table.get_blob (), nullptr);
// Copy everything over
@@ -120,48 +115,30 @@
char * dest_pos = (char *) dest;
bool failed = false;
- for (unsigned int i = 0; i < gids.length; i++)
+ for (unsigned int i = 0; i < num_output_glyphs; i++)
{
- /* the last metric or the one for gids[i] */
- LongMetric *src_metric = old_metrics + MIN ((hb_codepoint_t) _mtx.num_advances - 1, gids[i]);
- if (gids[i] < _mtx.num_advances)
+ unsigned int side_bearing = 0;
+ unsigned int advance = 0;
+ hb_codepoint_t old_gid;
+ if (plan->old_gid_for_new_gid (i, &old_gid))
{
- /* src is a LongMetric */
- if (i < num_advances)
- {
- /* dest is a LongMetric, copy it */
- *((LongMetric *) dest_pos) = *src_metric;
- }
- else
- {
- /* dest just sb */
- *((FWORD *) dest_pos) = src_metric->sb;
- }
+ // Glyph is not an empty glyph so copy advance and side bearing
+ // from the input font.
+ side_bearing = _mtx.get_side_bearing (old_gid);
+ advance = _mtx.get_advance (old_gid);
+ }
+
+ bool has_advance = i < num_advances;
+ if (has_advance)
+ {
+ ((LongMetric *) dest_pos)->advance = advance;
+ ((LongMetric *) dest_pos)->sb = side_bearing;
}
else
{
- if (gids[i] >= _mtx.num_metrics)
- {
- DEBUG_MSG(SUBSET, nullptr, "gid %d is >= number of source metrics %d",
- gids[i], _mtx.num_metrics);
- failed = true;
- break;
- }
- FWORD src_sb = *(lsbs + gids[i] - _mtx.num_advances);
- if (i < num_advances)
- {
- /* dest needs a full LongMetric */
- LongMetric *metric = (LongMetric *)dest_pos;
- metric->advance = src_metric->advance;
- metric->sb = src_sb;
- }
- else
- {
- /* dest just needs an sb */
- *((FWORD *) dest_pos) = src_sb;
- }
+ *((FWORD *) dest_pos) = side_bearing;
}
- dest_pos += (i < num_advances ? 4 : 2);
+ dest_pos += (has_advance ? 4 : 2);
}
_mtx.fini ();
@@ -187,7 +164,7 @@
friend struct hmtxvmtx;
void init (hb_face_t *face,
- unsigned int default_advance_ = 0)
+ unsigned int default_advance_ = 0)
{
default_advance = default_advance_ ? default_advance_ : hb_face_get_upem (face);
@@ -280,6 +257,32 @@
return advance;
}
+ unsigned int num_advances_for_subset (const hb_subset_plan_t *plan) const
+ {
+ unsigned int num_advances = plan->num_output_glyphs ();
+ unsigned int last_advance = _advance_for_new_gid (plan,
+ num_advances - 1);
+ while (num_advances > 1 &&
+ last_advance == _advance_for_new_gid (plan,
+ num_advances - 2))
+ {
+ num_advances--;
+ }
+
+ return num_advances;
+ }
+
+ private:
+ unsigned int _advance_for_new_gid (const hb_subset_plan_t *plan,
+ hb_codepoint_t new_gid) const
+ {
+ hb_codepoint_t old_gid;
+ if (!plan->old_gid_for_new_gid (new_gid, &old_gid))
+ return 0;
+
+ return get_advance (old_gid);
+ }
+
public:
bool has_font_extents;
int ascender;
diff --git a/src/hb-subset-plan.cc b/src/hb-subset-plan.cc
index dd00f4d..4b358ac 100644
--- a/src/hb-subset-plan.cc
+++ b/src/hb-subset-plan.cc
@@ -221,7 +221,7 @@
plan->glyphs,
plan->glyph_map,
plan->reverse_glyph_map,
- &plan->num_glyphs);
+ &plan->_num_output_glyphs);
return plan;
}
diff --git a/src/hb-subset-plan.hh b/src/hb-subset-plan.hh
index 7acb07a..f50610e 100644
--- a/src/hb-subset-plan.hh
+++ b/src/hb-subset-plan.hh
@@ -76,7 +76,7 @@
* The total number of output glyphs in the final subset.
*/
inline unsigned int
- num_output_glyphs ()
+ num_output_glyphs () const
{
return _num_output_glyphs;
}
