/* * Copyright © 2011,2012 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): Behdad Esfahbod, Roderick Sheeter */ #ifndef HB_OT_HMTX_TABLE_HH #define HB_OT_HMTX_TABLE_HH #include "hb-open-type.hh" #include "hb-ot-hhea-table.hh" #include "hb-ot-os2-table.hh" #include "hb-ot-var-hvar-table.hh" /* * hmtx -- Horizontal Metrics * https://docs.microsoft.com/en-us/typography/opentype/spec/hmtx * vmtx -- Vertical Metrics * https://docs.microsoft.com/en-us/typography/opentype/spec/vmtx */ #define HB_OT_TAG_hmtx HB_TAG('h','m','t','x') #define HB_OT_TAG_vmtx HB_TAG('v','m','t','x') namespace OT { struct LongMetric { UFWORD advance; /* Advance width/height. */ FWORD sb; /* Leading (left/top) side bearing. */ public: DEFINE_SIZE_STATIC (4); }; template struct hmtxvmtx { bool sanitize (hb_sanitize_context_t *c HB_UNUSED) const { TRACE_SANITIZE (this); /* We don't check for anything specific here. The users of the * struct do all the hard work... */ return_trace (true); } bool subset_update_header (hb_subset_plan_t *plan, unsigned int num_hmetrics) const { hb_blob_t *src_blob = hb_sanitize_context_t ().reference_table (plan->source, H::tableTag); hb_blob_t *dest_blob = hb_blob_copy_writable_or_fail (src_blob); hb_blob_destroy (src_blob); if (unlikely (!dest_blob)) { return false; } unsigned int length; H *table = (H *) hb_blob_get_data (dest_blob, &length); table->numberOfLongMetrics.set (num_hmetrics); bool result = plan->add_table (H::tableTag, dest_blob); hb_blob_destroy (dest_blob); return result; } bool subset (hb_subset_plan_t *plan) const { typename T::accelerator_t _mtx; _mtx.init (plan->source); /* All the trailing glyphs with the same advance can use one LongMetric * and just keep LSB */ 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 + (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, num_output_glyphs - num_advances, (unsigned int) dest_sz); // Copy everything over char * dest_pos = (char *) dest; bool failed = false; for (unsigned int i = 0; i < num_output_glyphs; i++) { unsigned int side_bearing = 0; unsigned int advance = 0; hb_codepoint_t old_gid; if (plan->old_gid_for_new_gid (i, &old_gid)) { // 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.set (advance); ((LongMetric *) dest_pos)->sb.set (side_bearing); } else { ((FWORD *) dest_pos)->set (side_bearing); } dest_pos += (has_advance ? 4 : 2); } _mtx.fini (); // Amend header num hmetrics if (failed || unlikely (!subset_update_header (plan, num_advances))) { free (dest); return false; } hb_blob_t *result = hb_blob_create ((const char *)dest, dest_sz, HB_MEMORY_MODE_READONLY, dest, free); bool success = plan->add_table (T::tableTag, result); hb_blob_destroy (result); return success; } struct accelerator_t { friend struct hmtxvmtx; void init (hb_face_t *face, unsigned int default_advance_ = 0) { default_advance = default_advance_ ? default_advance_ : hb_face_get_upem (face); bool got_font_extents = false; if (T::os2Tag != HB_TAG_NONE && face->table.OS2->is_typo_metrics ()) { ascender = abs (face->table.OS2->sTypoAscender); descender = -abs (face->table.OS2->sTypoDescender); line_gap = face->table.OS2->sTypoLineGap; got_font_extents = (ascender | descender) != 0; } hb_blob_t *_hea_blob = hb_sanitize_context_t().reference_table (face); const H *_hea_table = _hea_blob->as (); num_advances = _hea_table->numberOfLongMetrics; if (!got_font_extents) { ascender = abs (_hea_table->ascender); descender = -abs (_hea_table->descender); line_gap = _hea_table->lineGap; got_font_extents = (ascender | descender) != 0; } hb_blob_destroy (_hea_blob); has_font_extents = got_font_extents; table = hb_sanitize_context_t().reference_table (face, T::tableTag); /* Cap num_metrics() and num_advances() based on table length. */ unsigned int len = table.get_length (); if (unlikely (num_advances * 4 > len)) num_advances = len / 4; num_metrics = num_advances + (len - 4 * num_advances) / 2; /* We MUST set num_metrics to zero if num_advances is zero. * Our get_advance() depends on that. */ if (unlikely (!num_advances)) { num_metrics = num_advances = 0; table.destroy (); table = hb_blob_get_empty (); } var_table = hb_sanitize_context_t().reference_table (face, T::variationsTag); } void fini () { table.destroy (); var_table.destroy (); } /* TODO Add variations version. */ unsigned int get_side_bearing (hb_codepoint_t glyph) const { if (glyph < num_advances) return table->longMetricZ[glyph].sb; if (unlikely (glyph >= num_metrics)) return 0; const FWORD *bearings = (const FWORD *) &table->longMetricZ[num_advances]; return bearings[glyph - num_advances]; } unsigned int get_advance (hb_codepoint_t glyph) const { if (unlikely (glyph >= num_metrics)) { /* If num_metrics is zero, it means we don't have the metrics table * for this direction: return default advance. Otherwise, it means that the * glyph index is out of bound: return zero. */ if (num_metrics) return 0; else return default_advance; } return table->longMetricZ[MIN (glyph, (uint32_t) num_advances - 1)].advance; } unsigned int get_advance (hb_codepoint_t glyph, hb_font_t *font) const { unsigned int advance = get_advance (glyph); if (likely (glyph < num_metrics)) { advance += (font->num_coords ? var_table->get_advance_var (glyph, font->coords, font->num_coords) : 0); // TODO Optimize?! } 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; int descender; int line_gap; protected: unsigned int num_metrics; unsigned int num_advances; unsigned int default_advance; private: hb_blob_ptr_t table; hb_blob_ptr_t var_table; }; protected: UnsizedArrayOflongMetricZ;/* Paired advance width and leading * bearing values for each glyph. The * value numOfHMetrics comes from * the 'hhea' table. If the font is * monospaced, only one entry need * be in the array, but that entry is * required. The last entry applies to * all subsequent glyphs. */ /*UnsizedArrayOf leadingBearingX;*//* Here the advance is assumed * to be the same as the advance * for the last entry above. The * number of entries in this array is * derived from numGlyphs (from 'maxp' * table) minus numberOfLongMetrics. * This generally is used with a run * of monospaced glyphs (e.g., Kanji * fonts or Courier fonts). Only one * run is allowed and it must be at * the end. This allows a monospaced * font to vary the side bearing * values for each glyph. */ public: DEFINE_SIZE_ARRAY (0, longMetricZ); }; struct hmtx : hmtxvmtx { static constexpr hb_tag_t tableTag = HB_OT_TAG_hmtx; static constexpr hb_tag_t variationsTag = HB_OT_TAG_HVAR; static constexpr hb_tag_t os2Tag = HB_OT_TAG_OS2; }; struct vmtx : hmtxvmtx { static constexpr hb_tag_t tableTag = HB_OT_TAG_vmtx; static constexpr hb_tag_t variationsTag = HB_OT_TAG_VVAR; static constexpr hb_tag_t os2Tag = HB_TAG_NONE; }; struct hmtx_accelerator_t : hmtx::accelerator_t {}; struct vmtx_accelerator_t : vmtx::accelerator_t {}; } /* namespace OT */ #endif /* HB_OT_HMTX_TABLE_HH */