/* * Copyright © 2018 Google, Inc. * * This is part of HarfBuzz, a text shaping library. * * Permission is hereby granted, without written agreement and without * license or royalty fees, to use, copy, modify, and distribute this * software and its documentation for any purpose, provided that the * above copyright notice and the following two paragraphs appear in * all copies of this software. * * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH * DAMAGE. * * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. * * Google Author(s): Garret Rieger, Rod Sheeter, Behdad Esfahbod */ #include "hb.hh" #include "hb-open-type.hh" #include "hb-subset.hh" #include "hb-subset-glyf.hh" #include "hb-open-file.hh" #include "hb-ot-cmap-table.hh" #include "hb-ot-glyf-table.hh" #include "hb-ot-hdmx-table.hh" #include "hb-ot-head-table.hh" #include "hb-ot-hhea-table.hh" #include "hb-ot-hmtx-table.hh" #include "hb-ot-maxp-table.hh" #include "hb-ot-os2-table.hh" #include "hb-ot-post-table.hh" #include "hb-ot-cff1-table.hh" #include "hb-ot-cff2-table.hh" #include "hb-ot-vorg-table.hh" #include "hb-ot-layout-gsub-table.hh" #include "hb-ot-layout-gpos-table.hh" static unsigned int _plan_estimate_subset_table_size (hb_subset_plan_t *plan, unsigned int table_len) { unsigned int src_glyphs = plan->source->get_num_glyphs (); unsigned int dst_glyphs = plan->glyphset->get_population (); if (unlikely (!src_glyphs)) return 512 + table_len; return 512 + (unsigned int) (table_len * sqrt ((double) dst_glyphs / src_glyphs)); } template static bool _subset2 (hb_subset_plan_t *plan) { hb_blob_t *source_blob = hb_sanitize_context_t ().reference_table (plan->source); const TableType *table = source_blob->as (); hb_tag_t tag = TableType::tableTag; hb_bool_t result = false; if (source_blob->data) { hb_vector_t buf; unsigned int buf_size = _plan_estimate_subset_table_size (plan, source_blob->length); DEBUG_MSG(SUBSET, nullptr, "OT::%c%c%c%c initial estimated table size: %u bytes.", HB_UNTAG (tag), buf_size); if (unlikely (!buf.alloc (buf_size))) { DEBUG_MSG(SUBSET, nullptr, "OT::%c%c%c%c failed to allocate %u bytes.", HB_UNTAG (tag), buf_size); return false; } retry: hb_serialize_context_t serializer ((void *) buf, buf_size); hb_subset_context_t c (plan, &serializer); result = table->subset (&c); if (serializer.in_error ()) { buf_size += (buf_size >> 1) + 32; DEBUG_MSG(SUBSET, nullptr, "OT::%c%c%c%c ran out of room; reallocating to %u bytes.", HB_UNTAG (tag), buf_size); if (unlikely (!buf.alloc (buf_size))) { DEBUG_MSG(SUBSET, nullptr, "OT::%c%c%c%c failed to reallocate %u bytes.", HB_UNTAG (tag), buf_size); return false; } goto retry; } if (result) { hb_blob_t *dest_blob = serializer.copy_blob (); DEBUG_MSG(SUBSET, nullptr, "OT::%c%c%c%c final subset table size: %u bytes.", HB_UNTAG (tag), dest_blob->length); result = c.plan->add_table (tag, dest_blob); hb_blob_destroy (dest_blob); } else { DEBUG_MSG(SUBSET, nullptr, "OT::%c%c%c%c::subset table subsetted to empty.", HB_UNTAG (tag)); result = true; } } else DEBUG_MSG(SUBSET, nullptr, "OT::%c%c%c%c::subset sanitize failed on source table.", HB_UNTAG (tag)); hb_blob_destroy (source_blob); DEBUG_MSG(SUBSET, nullptr, "OT::%c%c%c%c::subset %s", HB_UNTAG (tag), result ? "success" : "FAILED!"); return result; } template static bool _subset (hb_subset_plan_t *plan) { hb_blob_t *source_blob = hb_sanitize_context_t ().reference_table (plan->source); const TableType *table = source_blob->as (); hb_tag_t tag = TableType::tableTag; hb_bool_t result = false; if (source_blob->data) result = table->subset (plan); else DEBUG_MSG(SUBSET, nullptr, "OT::%c%c%c%c::subset sanitize failed on source table.", HB_UNTAG (tag)); hb_blob_destroy (source_blob); DEBUG_MSG(SUBSET, nullptr, "OT::%c%c%c%c::subset %s", HB_UNTAG (tag), result ? "success" : "FAILED!"); return result; } static bool _subset_table (hb_subset_plan_t *plan, hb_tag_t tag) { DEBUG_MSG(SUBSET, nullptr, "begin subset %c%c%c%c", HB_UNTAG (tag)); bool result = true; switch (tag) { case HB_OT_TAG_glyf: result = _subset (plan); break; case HB_OT_TAG_hdmx: result = _subset (plan); break; case HB_OT_TAG_head: // TODO that won't work well if there is no glyf DEBUG_MSG(SUBSET, nullptr, "skip head, handled by glyf"); result = true; break; case HB_OT_TAG_hhea: DEBUG_MSG(SUBSET, nullptr, "skip hhea handled by hmtx"); return true; case HB_OT_TAG_hmtx: result = _subset (plan); break; case HB_OT_TAG_vhea: DEBUG_MSG(SUBSET, nullptr, "skip vhea handled by vmtx"); return true; case HB_OT_TAG_vmtx: result = _subset (plan); break; case HB_OT_TAG_maxp: result = _subset (plan); break; case HB_OT_TAG_loca: DEBUG_MSG(SUBSET, nullptr, "skip loca handled by glyf"); return true; case HB_OT_TAG_cmap: result = _subset (plan); break; case HB_OT_TAG_OS2: result = _subset (plan); break; case HB_OT_TAG_post: result = _subset (plan); break; case HB_OT_TAG_cff1: result = _subset (plan); break; case HB_OT_TAG_cff2: result = _subset (plan); break; case HB_OT_TAG_VORG: result = _subset (plan); break; case HB_OT_TAG_GDEF: result = _subset2 (plan); break; case HB_OT_TAG_GSUB: result = _subset2 (plan); break; case HB_OT_TAG_GPOS: result = _subset2 (plan); break; default: hb_blob_t *source_table = hb_face_reference_table (plan->source, tag); if (likely (source_table)) result = plan->add_table (tag, source_table); else result = false; hb_blob_destroy (source_table); break; } DEBUG_MSG(SUBSET, nullptr, "subset %c%c%c%c %s", HB_UNTAG (tag), result ? "ok" : "FAILED"); return result; } static bool _should_drop_table (hb_subset_plan_t *plan, hb_tag_t tag) { switch (tag) { case HB_TAG ('c', 'v', 'a', 'r'): /* hint table, fallthrough */ case HB_TAG ('c', 'v', 't', ' '): /* hint table, fallthrough */ case HB_TAG ('f', 'p', 'g', 'm'): /* hint table, fallthrough */ case HB_TAG ('p', 'r', 'e', 'p'): /* hint table, fallthrough */ case HB_TAG ('h', 'd', 'm', 'x'): /* hint table, fallthrough */ case HB_TAG ('V', 'D', 'M', 'X'): /* hint table, fallthrough */ return plan->drop_hints; // Drop Layout Tables if requested. case HB_OT_TAG_GDEF: case HB_OT_TAG_GPOS: case HB_OT_TAG_GSUB: return plan->drop_layout; // Drop these tables below by default, list pulled // from fontTools: case HB_TAG ('B', 'A', 'S', 'E'): case HB_TAG ('J', 'S', 'T', 'F'): case HB_TAG ('D', 'S', 'I', 'G'): case HB_TAG ('E', 'B', 'D', 'T'): case HB_TAG ('E', 'B', 'L', 'C'): case HB_TAG ('E', 'B', 'S', 'C'): case HB_TAG ('S', 'V', 'G', ' '): case HB_TAG ('P', 'C', 'L', 'T'): case HB_TAG ('L', 'T', 'S', 'H'): // Graphite tables: case HB_TAG ('F', 'e', 'a', 't'): case HB_TAG ('G', 'l', 'a', 't'): case HB_TAG ('G', 'l', 'o', 'c'): case HB_TAG ('S', 'i', 'l', 'f'): case HB_TAG ('S', 'i', 'l', 'l'): // Colour case HB_TAG ('s', 'b', 'i', 'x'): return true; default: return false; } } /** * hb_subset: * @source: font face data to be subset. * @input: input to use for the subsetting. * * Subsets a font according to provided input. **/ hb_face_t * hb_subset (hb_face_t *source, hb_subset_input_t *input) { if (unlikely (!input || !source)) return hb_face_get_empty (); hb_subset_plan_t *plan = hb_subset_plan_create (source, input); hb_tag_t table_tags[32]; unsigned int offset = 0, count; bool success = true; do { count = ARRAY_LENGTH (table_tags); hb_face_get_table_tags (source, offset, &count, table_tags); for (unsigned int i = 0; i < count; i++) { hb_tag_t tag = table_tags[i]; if (_should_drop_table (plan, tag)) { DEBUG_MSG(SUBSET, nullptr, "drop %c%c%c%c", HB_UNTAG (tag)); continue; } success = success && _subset_table (plan, tag); } offset += count; } while (success && count == ARRAY_LENGTH (table_tags)); hb_face_t *result = success ? hb_face_reference (plan->dest) : hb_face_get_empty (); hb_subset_plan_destroy (plan); return result; }