Introduce get_extent support for color bitmap font. (#351)
hb_font_get_glyph_extents now works for color bitmap fonts. Currently only font having index format 1 and image format 17 is supported.
This commit is contained in:
Seigo Nonaka
Behdad Esfahbod
parent
261837e720
commit
831852594b
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@ -21,6 +21,7 @@ HB_BASE_sources = \
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hb-open-file-private.hh \
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hb-open-type-private.hh \
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hb-ot-cmap-table.hh \
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hb-ot-ebdt-table.hh \
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hb-ot-glyf-table.hh \
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hb-ot-head-table.hh \
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hb-ot-hhea-table.hh \
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@ -0,0 +1,193 @@
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/*
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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_EBDT_TABLE_HH
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#define HB_OT_EBDT_TABLE_HH
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#include "hb-open-type-private.hh"
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namespace OT {
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struct SmallGlyphMetrics
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{
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BYTE height;
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BYTE width;
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int8_t bearingX;
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int8_t bearingY;
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BYTE advance;
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DEFINE_SIZE_STATIC(5);
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};
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struct SBitLineMetrics {
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int8_t ascender;
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int8_t decender;
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BYTE widthMax;
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int8_t caretSlopeNumerator;
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int8_t caretSlopeDenominator;
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int8_t caretOffset;
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int8_t minOriginSB;
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int8_t minAdvanceSB;
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int8_t maxBeforeBL;
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int8_t minAfterBL;
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int8_t padding1;
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int8_t padding2;
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DEFINE_SIZE_STATIC(12);
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};
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struct BitmapSizeTable
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{
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ULONG indexSubtableArrayOffset;
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ULONG indexTablesSize;
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ULONG numberOfIndexSubtables;
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ULONG colorRef;
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SBitLineMetrics horizontal;
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SBitLineMetrics vertical;
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USHORT startGlyphIndex;
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USHORT endGlyphIndex;
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BYTE ppemX;
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BYTE ppemY;
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BYTE bitDepth;
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int8_t flags;
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DEFINE_SIZE_STATIC(48);
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};
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/*
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* Index Subtables.
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*/
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struct IndexSubtable
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{
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USHORT firstGlyphIndex;
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USHORT lastGlyphIndex;
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ULONG offsetToSubtable;
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DEFINE_SIZE_STATIC(8);
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};
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struct IndexSubHeader
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{
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USHORT indexFormat;
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USHORT imageFormat;
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ULONG imageDataOffset;
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};
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struct IndexSubtableFormat1
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{
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IndexSubHeader header;
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ULONG offsetArray[VAR];
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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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ULONG dataLen;
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BYTE data[VAR];
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};
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struct IndexSubtableArray
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{
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public:
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const IndexSubtable* 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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unsigned int firstGlyphIndex = indexSubtables[i].firstGlyphIndex;
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unsigned int lastGlyphIndex = indexSubtables[i].lastGlyphIndex;
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if (firstGlyphIndex <= glyph && glyph <= lastGlyphIndex) {
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return &indexSubtables[i];
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}
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}
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return NULL;
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}
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protected:
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IndexSubtable indexSubtables[VAR];
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};
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/*
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* CBLC -- Color Bitmap Location Table
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*/
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#define HB_OT_TAG_CBLC HB_TAG('C','B','L','C')
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struct CBLC
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{
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static const hb_tag_t tableTag = HB_OT_TAG_CBLC;
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inline 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 (true);
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}
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public:
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const BitmapSizeTable* find_table(hb_codepoint_t glyph) const
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{
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// TODO: Make it possible to select strike.
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const uint32_t tableSize = numSizes;
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for (uint32_t i = 0; i < tableSize; ++i) {
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unsigned int startGlyphIndex = sizeTables[i].startGlyphIndex;
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unsigned int endGlyphIndex = sizeTables[i].endGlyphIndex;
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if (startGlyphIndex <= glyph && glyph <= endGlyphIndex) {
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return &sizeTables[i];
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}
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}
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return NULL;
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}
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protected:
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ULONG version;
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ULONG numSizes;
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BitmapSizeTable sizeTables[VAR];
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};
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/*
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* CBDT -- Color Bitmap Data Table
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*/
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#define HB_OT_TAG_CBDT HB_TAG('C','B','D','T')
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struct CBDT
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{
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static const hb_tag_t tableTag = HB_OT_TAG_CBDT;
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inline 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 (true);
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}
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protected:
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BYTE data[VAR];
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};
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} /* namespace OT */
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#endif /* HB_OT_EBDT_TABLE_HH */
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@ -31,6 +31,7 @@
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#include "hb-font-private.hh"
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#include "hb-ot-cmap-table.hh"
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#include "hb-ot-ebdt-table.hh"
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#include "hb-ot-glyf-table.hh"
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#include "hb-ot-head-table.hh"
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#include "hb-ot-hhea-table.hh"
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@ -207,6 +208,96 @@ struct hb_ot_face_glyf_accelerator_t
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}
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};
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struct hb_ot_face_ebdt_accelerator_t
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{
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hb_blob_t *cblc_blob = NULL;
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hb_blob_t *cbdt_blob = NULL;
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const OT::CBLC *cblc = NULL;
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const OT::CBDT *cbdt = NULL;
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float upem = 0.0f;
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inline void init (hb_face_t *face)
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{
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this->cblc_blob = OT::Sanitizer<OT::CBLC>::sanitize (face->reference_table (HB_OT_TAG_CBLC));
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this->cbdt_blob = OT::Sanitizer<OT::CBDT>::sanitize (face->reference_table (HB_OT_TAG_CBDT));
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if (hb_blob_get_length (this->cblc_blob) == 0) {
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return; /* Not a bitmap font. */
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}
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cblc = OT::Sanitizer<OT::CBLC>::lock_instance (this->cblc_blob);
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cbdt = OT::Sanitizer<OT::CBDT>::lock_instance (this->cbdt_blob);
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upem = face->get_upem();
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}
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inline void fini (void)
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{
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if (this->cblc_blob) {
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hb_blob_destroy (this->cblc_blob);
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hb_blob_destroy (this->cbdt_blob);
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}
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}
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inline bool get_extents (hb_codepoint_t glyph, hb_glyph_extents_t *extents) const
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{
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if (cblc == NULL) {
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return false; // Not a color bitmap font.
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}
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const OT::BitmapSizeTable* sizeTable = this->cblc->find_table(glyph);
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if (sizeTable == NULL) {
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return false;
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}
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const OT::IndexSubtableArray& subtables =
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OT::StructAtOffset<OT::IndexSubtableArray> (this->cblc, sizeTable->indexSubtableArrayOffset);
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const OT::IndexSubtable* subtable = subtables.find_table(glyph, sizeTable->numberOfIndexSubtables);
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if (subtable == NULL) {
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return false;
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}
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unsigned int offsetToSubtable = sizeTable->indexSubtableArrayOffset + subtable->offsetToSubtable;
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const OT::IndexSubHeader& header =
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OT::StructAtOffset<OT::IndexSubHeader> (this->cblc, offsetToSubtable);
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unsigned int imageDataOffset = header.imageDataOffset;
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switch (header.indexFormat) {
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case 1: {
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const OT::IndexSubtableFormat1& format1 =
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OT::StructAtOffset<OT::IndexSubtableFormat1> (this->cblc, offsetToSubtable);
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imageDataOffset += format1.offsetArray[glyph - subtable->firstGlyphIndex];
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switch (header.imageFormat) {
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case 17: {
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const OT::GlyphBitmapDataFormat17& glyphFormat17 =
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OT::StructAtOffset<OT::GlyphBitmapDataFormat17> (this->cbdt, imageDataOffset);
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extents->x_bearing = glyphFormat17.glyphMetrics.bearingX;
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extents->y_bearing = glyphFormat17.glyphMetrics.bearingY;
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extents->width = glyphFormat17.glyphMetrics.width;
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extents->height = -glyphFormat17.glyphMetrics.height;
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}
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break;
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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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break;
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default:
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// TODO: Support other index subtable format.
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return false;
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}
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// Convert to the font units.
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extents->x_bearing *= upem / (float)(sizeTable->ppemX);
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extents->y_bearing *= upem / (float)(sizeTable->ppemY);
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extents->width *= upem / (float)(sizeTable->ppemX);
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extents->height *= upem / (float)(sizeTable->ppemY);
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return true;
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}
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};
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typedef bool (*hb_cmap_get_glyph_func_t) (const void *obj,
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hb_codepoint_t codepoint,
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hb_codepoint_t *glyph);
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@ -379,6 +470,7 @@ struct hb_ot_font_t
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hb_ot_face_metrics_accelerator_t h_metrics;
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hb_ot_face_metrics_accelerator_t v_metrics;
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hb_lazy_loader_t<hb_ot_face_glyf_accelerator_t> glyf;
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hb_lazy_loader_t<hb_ot_face_ebdt_accelerator_t> ebdt;
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};
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@ -395,6 +487,7 @@ _hb_ot_font_create (hb_face_t *face)
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ot_font->v_metrics.init (face, HB_OT_TAG_vhea, HB_OT_TAG_vmtx, HB_TAG_NONE,
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ot_font->h_metrics.ascender - ot_font->h_metrics.descender); /* TODO Can we do this lazily? */
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ot_font->glyf.init (face);
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ot_font->ebdt.init (face);
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return ot_font;
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}
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@ -406,6 +499,7 @@ _hb_ot_font_destroy (hb_ot_font_t *ot_font)
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ot_font->h_metrics.fini ();
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ot_font->v_metrics.fini ();
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ot_font->glyf.fini ();
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ot_font->ebdt.fini ();
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free (ot_font);
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}
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@ -464,6 +558,8 @@ hb_ot_get_glyph_extents (hb_font_t *font HB_UNUSED,
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{
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const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
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bool ret = ot_font->glyf->get_extents (glyph, extents);
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if ( !ret )
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ret = ot_font->ebdt->get_extents (glyph, extents);
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extents->x_bearing = font->em_scale_x (extents->x_bearing);
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extents->y_bearing = font->em_scale_y (extents->y_bearing);
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extents->width = font->em_scale_x (extents->width);
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