536 lines
14 KiB
C++
536 lines
14 KiB
C++
/*
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* Copyright © 2016 Google, Inc.
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*
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* This is part of HarfBuzz, a text shaping library.
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*
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* Permission is hereby granted, without written agreement and without
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* license or royalty fees, to use, copy, modify, and distribute this
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* software and its documentation for any purpose, provided that the
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* above copyright notice and the following two paragraphs appear in
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* all copies of this software.
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*
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* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
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* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
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* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
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* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
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* DAMAGE.
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*
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* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
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* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
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* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
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* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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*
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* Google Author(s): Seigo Nonaka
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*/
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#ifndef HB_OT_COLOR_CBDT_TABLE_HH
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#define HB_OT_COLOR_CBDT_TABLE_HH
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#include "hb-open-type.hh"
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/*
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* CBLC -- Color Bitmap Location
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* https://docs.microsoft.com/en-us/typography/opentype/spec/cblc
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* https://docs.microsoft.com/en-us/typography/opentype/spec/eblc
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* CBDT -- Color Bitmap Data
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* https://docs.microsoft.com/en-us/typography/opentype/spec/cbdt
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* https://docs.microsoft.com/en-us/typography/opentype/spec/ebdt
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*/
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#define HB_OT_TAG_CBLC HB_TAG('C','B','L','C')
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#define HB_OT_TAG_CBDT HB_TAG('C','B','D','T')
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namespace OT {
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struct SmallGlyphMetrics
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{
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bool sanitize (hb_sanitize_context_t *c) const
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{
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TRACE_SANITIZE (this);
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return_trace (c->check_struct (this));
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}
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void get_extents (hb_glyph_extents_t *extents) const
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{
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extents->x_bearing = bearingX;
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extents->y_bearing = bearingY;
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extents->width = width;
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extents->height = -height;
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}
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HBUINT8 height;
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HBUINT8 width;
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HBINT8 bearingX;
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HBINT8 bearingY;
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HBUINT8 advance;
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public:
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DEFINE_SIZE_STATIC(5);
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};
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struct BigGlyphMetrics : SmallGlyphMetrics
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{
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HBINT8 vertBearingX;
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HBINT8 vertBearingY;
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HBUINT8 vertAdvance;
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public:
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DEFINE_SIZE_STATIC(8);
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};
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struct SBitLineMetrics
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{
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bool sanitize (hb_sanitize_context_t *c) const
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{
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TRACE_SANITIZE (this);
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return_trace (c->check_struct (this));
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}
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HBINT8 ascender;
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HBINT8 decender;
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HBUINT8 widthMax;
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HBINT8 caretSlopeNumerator;
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HBINT8 caretSlopeDenominator;
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HBINT8 caretOffset;
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HBINT8 minOriginSB;
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HBINT8 minAdvanceSB;
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HBINT8 maxBeforeBL;
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HBINT8 minAfterBL;
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HBINT8 padding1;
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HBINT8 padding2;
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public:
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DEFINE_SIZE_STATIC(12);
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};
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/*
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* Index Subtables.
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*/
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struct IndexSubtableHeader
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{
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bool sanitize (hb_sanitize_context_t *c) const
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{
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TRACE_SANITIZE (this);
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return_trace (c->check_struct (this));
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}
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HBUINT16 indexFormat;
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HBUINT16 imageFormat;
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HBUINT32 imageDataOffset;
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public:
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DEFINE_SIZE_STATIC(8);
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};
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template <typename OffsetType>
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struct IndexSubtableFormat1Or3
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{
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bool sanitize (hb_sanitize_context_t *c, unsigned int glyph_count) const
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{
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TRACE_SANITIZE (this);
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return_trace (c->check_struct (this) &&
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offsetArrayZ.sanitize (c, glyph_count + 1));
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}
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bool get_image_data (unsigned int idx,
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unsigned int *offset,
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unsigned int *length) const
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{
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if (unlikely (offsetArrayZ[idx + 1] <= offsetArrayZ[idx]))
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return false;
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*offset = header.imageDataOffset + offsetArrayZ[idx];
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*length = offsetArrayZ[idx + 1] - offsetArrayZ[idx];
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return true;
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}
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IndexSubtableHeader header;
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UnsizedArrayOf<Offset<OffsetType> >
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offsetArrayZ;
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public:
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DEFINE_SIZE_ARRAY(8, offsetArrayZ);
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};
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struct IndexSubtableFormat1 : IndexSubtableFormat1Or3<HBUINT32> {};
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struct IndexSubtableFormat3 : IndexSubtableFormat1Or3<HBUINT16> {};
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struct IndexSubtable
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{
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bool sanitize (hb_sanitize_context_t *c, unsigned int glyph_count) const
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{
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TRACE_SANITIZE (this);
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if (!u.header.sanitize (c)) return_trace (false);
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switch (u.header.indexFormat) {
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case 1: return_trace (u.format1.sanitize (c, glyph_count));
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case 3: return_trace (u.format3.sanitize (c, glyph_count));
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default:return_trace (true);
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}
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}
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bool get_extents (hb_glyph_extents_t *extents HB_UNUSED) const
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{
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switch (u.header.indexFormat) {
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case 2: case 5: /* TODO */
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case 1: case 3: case 4: /* Variable-metrics formats do not have metrics here. */
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default:return (false);
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}
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}
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bool get_image_data (unsigned int idx,
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unsigned int *offset,
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unsigned int *length,
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unsigned int *format) const
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{
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*format = u.header.imageFormat;
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switch (u.header.indexFormat) {
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case 1: return u.format1.get_image_data (idx, offset, length);
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case 3: return u.format3.get_image_data (idx, offset, length);
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default: return false;
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}
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}
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protected:
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union {
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IndexSubtableHeader header;
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IndexSubtableFormat1 format1;
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IndexSubtableFormat3 format3;
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/* TODO: Format 2, 4, 5. */
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} u;
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public:
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DEFINE_SIZE_UNION (8, header);
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};
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struct IndexSubtableRecord
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{
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bool sanitize (hb_sanitize_context_t *c, const void *base) const
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{
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TRACE_SANITIZE (this);
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return_trace (c->check_struct (this) &&
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firstGlyphIndex <= lastGlyphIndex &&
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offsetToSubtable.sanitize (c, base, lastGlyphIndex - firstGlyphIndex + 1));
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}
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bool get_extents (hb_glyph_extents_t *extents,
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const void *base) const
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{
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return (base+offsetToSubtable).get_extents (extents);
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}
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bool get_image_data (unsigned int gid,
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const void *base,
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unsigned int *offset,
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unsigned int *length,
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unsigned int *format) const
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{
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if (gid < firstGlyphIndex || gid > lastGlyphIndex) return false;
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return (base+offsetToSubtable).get_image_data (gid - firstGlyphIndex,
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offset, length, format);
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}
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GlyphID firstGlyphIndex;
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GlyphID lastGlyphIndex;
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LOffsetTo<IndexSubtable> offsetToSubtable;
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public:
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DEFINE_SIZE_STATIC(8);
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};
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struct IndexSubtableArray
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{
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friend struct CBDT;
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bool sanitize (hb_sanitize_context_t *c, unsigned int count) const
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{
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TRACE_SANITIZE (this);
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return_trace (indexSubtablesZ.sanitize (c, count, this));
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}
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public:
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const IndexSubtableRecord* find_table (hb_codepoint_t glyph, unsigned int numTables) const
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{
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for (unsigned int i = 0; i < numTables; ++i)
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{
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unsigned int firstGlyphIndex = indexSubtablesZ[i].firstGlyphIndex;
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unsigned int lastGlyphIndex = indexSubtablesZ[i].lastGlyphIndex;
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if (firstGlyphIndex <= glyph && glyph <= lastGlyphIndex)
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return &indexSubtablesZ[i];
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}
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return nullptr;
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}
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protected:
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UnsizedArrayOf<IndexSubtableRecord> indexSubtablesZ;
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};
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struct BitmapSizeTable
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{
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friend struct CBLC;
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friend struct CBDT;
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bool sanitize (hb_sanitize_context_t *c, const void *base) const
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{
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TRACE_SANITIZE (this);
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return_trace (c->check_struct (this) &&
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indexSubtableArrayOffset.sanitize (c, base, numberOfIndexSubtables) &&
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horizontal.sanitize (c) &&
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vertical.sanitize (c));
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}
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const IndexSubtableRecord *find_table (hb_codepoint_t glyph,
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const void *base,
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const void **out_base) const
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{
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*out_base = &(base+indexSubtableArrayOffset);
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return (base+indexSubtableArrayOffset).find_table (glyph, numberOfIndexSubtables);
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}
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protected:
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LNNOffsetTo<IndexSubtableArray>
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indexSubtableArrayOffset;
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HBUINT32 indexTablesSize;
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HBUINT32 numberOfIndexSubtables;
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HBUINT32 colorRef;
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SBitLineMetrics horizontal;
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SBitLineMetrics vertical;
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GlyphID startGlyphIndex;
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GlyphID endGlyphIndex;
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HBUINT8 ppemX;
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HBUINT8 ppemY;
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HBUINT8 bitDepth;
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HBINT8 flags;
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public:
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DEFINE_SIZE_STATIC(48);
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};
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/*
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* Glyph Bitmap Data Formats.
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*/
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struct GlyphBitmapDataFormat17
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{
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SmallGlyphMetrics glyphMetrics;
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LArrayOf<HBUINT8> data;
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public:
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DEFINE_SIZE_ARRAY(9, data);
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};
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struct GlyphBitmapDataFormat18
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{
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BigGlyphMetrics glyphMetrics;
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LArrayOf<HBUINT8> data;
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public:
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DEFINE_SIZE_ARRAY(12, data);
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};
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struct GlyphBitmapDataFormat19
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{
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LArrayOf<HBUINT8> data;
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public:
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DEFINE_SIZE_ARRAY(4, data);
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};
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struct CBLC
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{
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friend struct CBDT;
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enum { tableTag = HB_OT_TAG_CBLC };
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bool sanitize (hb_sanitize_context_t *c) const
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{
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TRACE_SANITIZE (this);
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return_trace (c->check_struct (this) &&
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likely (version.major == 2 || version.major == 3) &&
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sizeTables.sanitize (c, this));
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}
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protected:
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const BitmapSizeTable &choose_strike (hb_font_t *font) const
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{
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unsigned count = sizeTables.len;
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if (unlikely (!count))
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return Null(BitmapSizeTable);
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unsigned int requested_ppem = MAX (font->x_ppem, font->y_ppem);
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if (!requested_ppem)
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requested_ppem = 1<<30; /* Choose largest strike. */
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unsigned int best_i = 0;
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unsigned int best_ppem = MAX (sizeTables[0].ppemX, sizeTables[0].ppemY);
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for (unsigned int i = 1; i < count; i++)
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{
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unsigned int ppem = MAX (sizeTables[i].ppemX, sizeTables[i].ppemY);
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if ((requested_ppem <= ppem && ppem < best_ppem) ||
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(requested_ppem > best_ppem && ppem > best_ppem))
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{
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best_i = i;
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best_ppem = ppem;
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}
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}
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return sizeTables[best_i];
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}
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protected:
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FixedVersion<> version;
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LArrayOf<BitmapSizeTable> sizeTables;
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public:
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DEFINE_SIZE_ARRAY(8, sizeTables);
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};
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struct CBDT
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{
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enum { tableTag = HB_OT_TAG_CBDT };
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struct accelerator_t
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{
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void init (hb_face_t *face)
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{
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cblc = hb_sanitize_context_t().reference_table<CBLC> (face);
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cbdt = hb_sanitize_context_t().reference_table<CBDT> (face);
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upem = hb_face_get_upem (face);
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}
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void fini ()
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{
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this->cblc.destroy ();
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this->cbdt.destroy ();
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}
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bool get_extents (hb_font_t *font, hb_codepoint_t glyph,
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hb_glyph_extents_t *extents) const
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{
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const void *base;
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const BitmapSizeTable &strike = this->cblc->choose_strike (font);
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const IndexSubtableRecord *subtable_record = strike.find_table (glyph, cblc, &base);
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if (!subtable_record || !strike.ppemX || !strike.ppemY)
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return false;
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if (subtable_record->get_extents (extents, base))
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return true;
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unsigned int image_offset = 0, image_length = 0, image_format = 0;
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if (!subtable_record->get_image_data (glyph, base, &image_offset, &image_length, &image_format))
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return false;
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{
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unsigned int cbdt_len = cbdt.get_length ();
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if (unlikely (image_offset > cbdt_len || cbdt_len - image_offset < image_length))
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return false;
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switch (image_format)
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{
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case 17: {
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if (unlikely (image_length < GlyphBitmapDataFormat17::min_size))
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return false;
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const GlyphBitmapDataFormat17& glyphFormat17 =
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StructAtOffset<GlyphBitmapDataFormat17> (this->cbdt, image_offset);
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glyphFormat17.glyphMetrics.get_extents (extents);
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break;
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}
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case 18: {
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if (unlikely (image_length < GlyphBitmapDataFormat18::min_size))
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return false;
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const GlyphBitmapDataFormat18& glyphFormat18 =
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StructAtOffset<GlyphBitmapDataFormat18> (this->cbdt, image_offset);
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glyphFormat18.glyphMetrics.get_extents (extents);
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break;
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}
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default:
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// TODO: Support other image formats.
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return false;
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}
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}
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/* Convert to font units. */
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double x_scale = upem / (double) strike.ppemX;
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double y_scale = upem / (double) strike.ppemY;
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extents->x_bearing = round (extents->x_bearing * x_scale);
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extents->y_bearing = round (extents->y_bearing * y_scale);
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extents->width = round (extents->width * x_scale);
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extents->height = round (extents->height * y_scale);
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return true;
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}
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hb_blob_t* reference_png (hb_font_t *font,
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hb_codepoint_t glyph) const
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{
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const void *base;
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const BitmapSizeTable &strike = this->cblc->choose_strike (font);
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const IndexSubtableRecord *subtable_record = strike.find_table (glyph, cblc, &base);
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if (!subtable_record || !strike.ppemX || !strike.ppemY)
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return hb_blob_get_empty ();
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unsigned int image_offset = 0, image_length = 0, image_format = 0;
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if (!subtable_record->get_image_data (glyph, base, &image_offset, &image_length, &image_format))
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return hb_blob_get_empty ();
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{
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unsigned int cbdt_len = cbdt.get_length ();
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if (unlikely (image_offset > cbdt_len || cbdt_len - image_offset < image_length))
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return hb_blob_get_empty ();
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switch (image_format)
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{
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case 17: {
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if (unlikely (image_length < GlyphBitmapDataFormat17::min_size))
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return hb_blob_get_empty ();
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const GlyphBitmapDataFormat17& glyphFormat17 =
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StructAtOffset<GlyphBitmapDataFormat17> (this->cbdt, image_offset);
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return hb_blob_create_sub_blob (cbdt.get_blob (),
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image_offset + GlyphBitmapDataFormat17::min_size,
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glyphFormat17.data.len);
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}
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case 18: {
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if (unlikely (image_length < GlyphBitmapDataFormat18::min_size))
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return hb_blob_get_empty ();
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const GlyphBitmapDataFormat18& glyphFormat18 =
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StructAtOffset<GlyphBitmapDataFormat18> (this->cbdt, image_offset);
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return hb_blob_create_sub_blob (cbdt.get_blob (),
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image_offset + GlyphBitmapDataFormat18::min_size,
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glyphFormat18.data.len);
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}
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case 19: {
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if (unlikely (image_length < GlyphBitmapDataFormat19::min_size))
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return hb_blob_get_empty ();
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const GlyphBitmapDataFormat19& glyphFormat19 =
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StructAtOffset<GlyphBitmapDataFormat19> (this->cbdt, image_offset);
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return hb_blob_create_sub_blob (cbdt.get_blob (),
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image_offset + GlyphBitmapDataFormat19::min_size,
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glyphFormat19.data.len);
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}
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}
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}
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return hb_blob_get_empty ();
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}
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bool has_data () const { return cbdt.get_length (); }
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private:
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hb_blob_ptr_t<CBLC> cblc;
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hb_blob_ptr_t<CBDT> cbdt;
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unsigned int upem;
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};
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bool sanitize (hb_sanitize_context_t *c) const
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{
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TRACE_SANITIZE (this);
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return_trace (c->check_struct (this) &&
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likely (version.major == 2 || version.major == 3));
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}
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protected:
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FixedVersion<> version;
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UnsizedArrayOf<HBUINT8> dataZ;
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public:
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DEFINE_SIZE_ARRAY(4, dataZ);
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};
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struct CBDT_accelerator_t : CBDT::accelerator_t {};
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} /* namespace OT */
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#endif /* HB_OT_COLOR_CBDT_TABLE_HH */
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