[ot-font] Implement glyph_extents() for TrueType fonts
This brings ot-fonts into almost-complete shape and mostly in par with ft font.
This commit is contained in:
Behdad Esfahbod
parent
0299b45000
commit
b50fcfa829
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@ -41,6 +41,7 @@ HBSOURCES = \
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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-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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hb-ot-hmtx-table.hh \
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@ -80,12 +80,13 @@ hb_font_funcs_is_immutable (hb_font_funcs_t *ffuncs);
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/* glyph extents */
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/* Note that height is negative in coordinate systems that grow up. */
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typedef struct hb_glyph_extents_t
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{
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hb_position_t x_bearing;
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hb_position_t y_bearing;
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hb_position_t width;
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hb_position_t height;
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hb_position_t x_bearing; /* left side of glyph from origin. */
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hb_position_t y_bearing; /* top side of glyph from origin. */
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hb_position_t width; /* distance from left to right side. */
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hb_position_t height; /* distance from top to bottom side. */
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} hb_glyph_extents_t;
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@ -31,6 +31,8 @@
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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-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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#include "hb-ot-hmtx-table.hh"
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@ -76,8 +78,8 @@ struct hb_ot_face_metrics_accelerator_t
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if (unlikely (glyph >= this->num_metrics))
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{
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/* If this->num_metrics is zero, it means we don't have the metrics table
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* for this direction: return one EM. Otherwise, it means that the glyph
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* index is out of bound: return zero. */
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* for this direction: return default advance. Otherwise, it means that the
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* glyph index is out of bound: return zero. */
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if (this->num_metrics)
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return 0;
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else
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@ -91,6 +93,79 @@ struct hb_ot_face_metrics_accelerator_t
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}
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};
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struct hb_ot_face_glyf_accelerator_t
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{
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bool short_offset;
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unsigned int num_glyphs;
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const OT::loca *loca;
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const OT::glyf *glyf;
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hb_blob_t *loca_blob;
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hb_blob_t *glyf_blob;
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unsigned int glyf_len;
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inline void init (hb_face_t *face)
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{
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hb_blob_t *head_blob = OT::Sanitizer<OT::head>::sanitize (face->reference_table (HB_OT_TAG_head));
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const OT::head *head = OT::Sanitizer<OT::head>::lock_instance (head_blob);
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if ((unsigned int) head->indexToLocFormat > 1 || head->glyphDataFormat != 0)
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{
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/* Unknown format. Leave num_glyphs=0, that takes care of disabling us. */
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hb_blob_destroy (head_blob);
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return;
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}
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this->short_offset = 0 == head->indexToLocFormat;
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hb_blob_destroy (head_blob);
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this->loca_blob = OT::Sanitizer<OT::loca>::sanitize (face->reference_table (HB_OT_TAG_loca));
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this->loca = OT::Sanitizer<OT::loca>::lock_instance (this->loca_blob);
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this->glyf_blob = OT::Sanitizer<OT::glyf>::sanitize (face->reference_table (HB_OT_TAG_glyf));
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this->glyf = OT::Sanitizer<OT::glyf>::lock_instance (this->glyf_blob);
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this->num_glyphs = MAX (1u, hb_blob_get_length (this->loca_blob) / (this->short_offset ? 2 : 4)) - 1;
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this->glyf_len = hb_blob_get_length (this->glyf_blob);
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}
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inline void fini (void)
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{
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hb_blob_destroy (this->loca_blob);
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hb_blob_destroy (this->glyf_blob);
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}
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inline bool get_extents (hb_codepoint_t glyph,
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hb_glyph_extents_t *extents) const
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{
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if (unlikely (glyph >= this->num_glyphs))
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return false;
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unsigned int start_offset, end_offset;
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if (this->short_offset)
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{
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start_offset = this->loca->u.shortsZ[glyph];
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end_offset = this->loca->u.shortsZ[glyph + 1];
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}
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else
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{
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start_offset = this->loca->u.longsZ[glyph];
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end_offset = this->loca->u.longsZ[glyph + 1];
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}
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if (start_offset > end_offset || end_offset > this->glyf_len)
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return false;
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if (end_offset - start_offset < OT::glyfGlyphHeader::static_size)
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return true; /* Empty glyph; zero extents. */
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const OT::glyfGlyphHeader &glyph_header = OT::StructAtOffset<OT::glyfGlyphHeader> (this->glyf, start_offset);
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extents->x_bearing = MIN (glyph_header.xMin, glyph_header.xMax);
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extents->y_bearing = MAX (glyph_header.yMin, glyph_header.yMax);
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extents->width = MAX (glyph_header.xMin, glyph_header.xMax) - extents->x_bearing;
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extents->height = MIN (glyph_header.yMin, glyph_header.yMax) - extents->y_bearing;
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return true;
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}
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};
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struct hb_ot_face_cmap_accelerator_t
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{
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const OT::CmapSubtable *table;
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@ -158,6 +233,7 @@ struct hb_ot_font_t
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hb_ot_face_cmap_accelerator_t cmap;
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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_ot_face_glyf_accelerator_t glyf;
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};
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@ -175,6 +251,7 @@ _hb_ot_font_create (hb_font_t *font)
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ot_font->cmap.init (face);
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ot_font->h_metrics.init (face, HB_OT_TAG_hhea, HB_OT_TAG_hmtx, upem>>1);
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ot_font->v_metrics.init (face, HB_OT_TAG_vhea, HB_OT_TAG_vmtx, upem); /* TODO Can we do this lazily? */
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ot_font->glyf.init (face);
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return ot_font;
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}
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@ -276,8 +353,13 @@ hb_ot_get_glyph_extents (hb_font_t *font HB_UNUSED,
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hb_glyph_extents_t *extents,
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void *user_data HB_UNUSED)
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{
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/* TODO */
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return false;
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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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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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extents->height = font->em_scale_y (extents->height);
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return ret;
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}
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static hb_bool_t
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@ -0,0 +1,104 @@
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/*
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* Copyright © 2015 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): Behdad Esfahbod
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*/
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#ifndef HB_OT_GLYF_TABLE_HH
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#define HB_OT_GLYF_TABLE_HH
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#include "hb-open-type-private.hh"
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namespace OT {
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/*
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* loca -- Index to Location
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*/
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#define HB_OT_TAG_loca HB_TAG('l','o','c','a')
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struct loca
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{
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static const hb_tag_t tableTag = HB_OT_TAG_loca;
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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_RETURN (true);
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}
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public:
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union {
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USHORT shortsZ[VAR]; /* Location offset divided by 2. */
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ULONG longsZ[VAR]; /* Location offset. */
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} u;
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DEFINE_SIZE_ARRAY (0, u.longsZ);
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};
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/*
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* glyf -- TrueType Glyph Data
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*/
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#define HB_OT_TAG_glyf HB_TAG('g','l','y','f')
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struct glyf
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{
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static const hb_tag_t tableTag = HB_OT_TAG_glyf;
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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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/* We don't check for anything specific here. The users of the
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* struct do all the hard work... */
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return TRACE_RETURN (true);
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}
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public:
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BYTE dataX[VAR]; /* Glyphs data. */
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DEFINE_SIZE_ARRAY (0, dataX);
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};
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struct glyfGlyphHeader
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{
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SHORT numberOfContours; /* If the number of contours is
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* greater than or equal to zero,
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* this is a simple glyph; if negative,
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* this is a composite glyph. */
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SHORT xMin; /* Minimum x for coordinate data. */
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SHORT yMin; /* Minimum y for coordinate data. */
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SHORT xMax; /* Maximum x for coordinate data. */
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SHORT yMax; /* Maximum y for coordinate data. */
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DEFINE_SIZE_STATIC (10);
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};
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} /* namespace OT */
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#endif /* HB_OT_GLYF_TABLE_HH */
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@ -138,9 +138,10 @@ struct head
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* 2: Like 1 but also contains neutrals;
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* -1: Only strongly right to left;
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* -2: Like -1 but also contains neutrals. */
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public:
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SHORT indexToLocFormat; /* 0 for short offsets, 1 for long. */
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SHORT glyphDataFormat; /* 0 for current format. */
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public:
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DEFINE_SIZE_STATIC (54);
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};
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