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[subset] Complete implementation of cmap4 subsetting.

This commit is contained in:
Garret Rieger 2018-05-02 17:46:30 -07:00
parent 4195a52b04
commit 81ea75f5c8
1 changed files with 28 additions and 3 deletions
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31
src/hb-ot-cmap-table.hh
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@ -113,11 +113,36 @@ struct CmapSubtableFormat4
return false;
id_delta[i].set (start_gid - segments[i].start_code);
} else {
// TODO: fill out glyphIdArray and id_range_offset.
id_delta[i].set (0);
unsigned int num_codepoints = segments[i].end_code - segments[i].start_code + 1;
HBUINT16 *glyph_id_array = c->allocate_size<HBUINT16> (HBUINT16::static_size * num_codepoints);
// From the cmap spec:
//
// id_range_offset[i]/2
// + (cp - segments[i].start_code)
// + (id_range_offset + i)
// =
// glyph_id_array + (cp - segments[i].start_code)
//
// So, solve for id_range_offset[i]:
//
// id_range_offset[i]
// =
// 2 * (glyph_id_array - id_range_offset - i)
id_range_offset[i].set (2 * (
glyph_id_array - id_range_offset - i));
for (unsigned int j = 0; j < num_codepoints; j++)
{
hb_codepoint_t cp = segments[i].start_code + j;
hb_codepoint_t new_gid = 0; // Default to not def for 0xFFFF
if (unlikely (!hb_subset_plan_new_gid_for_codepoint (plan, cp, &new_gid) && cp != 0xFFFF))
return false;
glyph_id_array[j].set (new_gid);
}
}
}
// TODO: glyphdIdArray
return true;
}
static inline size_t get_sub_table_size (const hb_vector_t<segment_plan> &segments)
@ -181,7 +206,7 @@ struct CmapSubtableFormat4
segment = segments->push ();
segment->start_code.set (0xFFFF);
segment->end_code.set (0xFFFF);
segment->use_delta = true;
segment->use_delta = false;
}
last_gid = new_gid;