harfbuzz/src/hb-ot-glyf-table.hh

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/*
* Copyright © 2015 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
*/
#ifndef HB_OT_GLYF_TABLE_HH
#define HB_OT_GLYF_TABLE_HH
#include "hb-open-type-private.hh"
#include "hb-ot-head-table.hh"
#include "hb-subset-glyf.hh"
#include "hb-subset-plan.hh"
#include "hb-subset-private.hh"
namespace OT {
/*
* loca -- Index to Location
*/
#define HB_OT_TAG_loca HB_TAG('l','o','c','a')
struct loca
{
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friend struct glyf;
static const hb_tag_t tableTag = HB_OT_TAG_loca;
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (true);
}
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protected:
HBUINT8 dataX[VAR]; /* Location data. */
DEFINE_SIZE_ARRAY (0, dataX);
};
/*
* glyf -- TrueType Glyph Data
*/
#define HB_OT_TAG_glyf HB_TAG('g','l','y','f')
struct glyf
{
static const hb_tag_t tableTag = HB_OT_TAG_glyf;
inline bool sanitize (hb_sanitize_context_t *c) 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);
}
inline bool subset (hb_subset_plan_t *plan) const
{
hb_blob_t *glyf_prime = nullptr;
hb_blob_t *loca_prime = nullptr;
bool success = true;
bool use_short_loca = false;
if (hb_subset_glyf_and_loca (plan, &use_short_loca, &glyf_prime, &loca_prime)) {
success = success && hb_subset_plan_add_table (plan, HB_OT_TAG_glyf, glyf_prime);
success = success && hb_subset_plan_add_table (plan, HB_OT_TAG_loca, loca_prime);
success = success && _add_head_and_set_loca_version (plan->source, use_short_loca, plan->dest);
} else {
success = false;
}
hb_blob_destroy (loca_prime);
hb_blob_destroy (glyf_prime);
return success;
}
static bool
_add_head_and_set_loca_version (hb_face_t *source, bool use_short_loca, hb_face_t *dest)
{
hb_blob_t *head_blob = OT::Sanitizer<OT::head>().sanitize (hb_face_reference_table (source, HB_OT_TAG_head));
hb_blob_t *head_prime_blob = hb_blob_copy_writable_or_fail (head_blob);
hb_blob_destroy (head_blob);
if (unlikely (!head_prime_blob))
return false;
OT::head *head_prime = (OT::head *) hb_blob_get_data_writable (head_prime_blob, nullptr);
head_prime->indexToLocFormat.set (use_short_loca ? 0 : 1);
bool success = hb_subset_face_add_table (dest, HB_OT_TAG_head, head_prime_blob);
hb_blob_destroy (head_prime_blob);
return success;
}
struct GlyphHeader
{
HBINT16 numberOfContours; /* If the number of contours is
* greater than or equal to zero,
* this is a simple glyph; if negative,
* this is a composite glyph. */
FWORD xMin; /* Minimum x for coordinate data. */
FWORD yMin; /* Minimum y for coordinate data. */
FWORD xMax; /* Maximum x for coordinate data. */
FWORD yMax; /* Maximum y for coordinate data. */
DEFINE_SIZE_STATIC (10);
};
struct CompositeGlyphHeader
{
static const uint16_t ARG_1_AND_2_ARE_WORDS = 0x0001;
static const uint16_t ARGS_ARE_XY_VALUES = 0x0002;
static const uint16_t ROUND_XY_TO_GRID = 0x0004;
static const uint16_t WE_HAVE_A_SCALE = 0x0008;
static const uint16_t MORE_COMPONENTS = 0x0020;
static const uint16_t WE_HAVE_AN_X_AND_Y_SCALE = 0x0040;
static const uint16_t WE_HAVE_A_TWO_BY_TWO = 0x0080;
static const uint16_t WE_HAVE_INSTRUCTIONS = 0x0100;
static const uint16_t USE_MY_METRICS = 0x0200;
static const uint16_t OVERLAP_COMPOUND = 0x0400;
static const uint16_t SCALED_COMPONENT_OFFSET = 0x0800;
static const uint16_t UNSCALED_COMPONENT_OFFSET = 0x1000;
HBUINT16 flags;
HBUINT16 glyphIndex;
inline unsigned int get_size (void) const
{
unsigned int size = min_size;
if (flags & ARG_1_AND_2_ARE_WORDS) {
// arg1 and 2 are int16
size += 4;
} else {
// arg1 and 2 are int8
size += 2;
}
if (flags & WE_HAVE_A_SCALE) {
// One x 16 bit (scale)
size += 2;
} else if (flags & WE_HAVE_AN_X_AND_Y_SCALE) {
// Two x 16 bit (xscale, yscale)
size += 4;
} else if (flags & WE_HAVE_A_TWO_BY_TWO) {
// Four x 16 bit (xscale, scale01, scale10, yscale)
size += 8;
}
return size;
}
struct Iterator
{
const char *glyph_start;
const char *glyph_end;
const CompositeGlyphHeader *current;
inline bool move_to_next ()
{
if (current->flags & CompositeGlyphHeader::MORE_COMPONENTS)
{
const CompositeGlyphHeader *possible =
&StructAfter<CompositeGlyphHeader, CompositeGlyphHeader> (*current);
if (!in_range (possible))
return false;
current = possible;
return true;
}
return false;
}
inline bool in_range (const CompositeGlyphHeader *composite) const
{
return (const char *) composite >= glyph_start
&& ((const char *) composite + CompositeGlyphHeader::min_size) <= glyph_end
&& ((const char *) composite + composite->get_size()) <= glyph_end;
}
};
static inline bool get_iterator (const char * glyph_data,
unsigned int length,
CompositeGlyphHeader::Iterator *iterator /* OUT */)
{
if (length < GlyphHeader::static_size)
return false; /* Empty glyph; zero extents. */
const GlyphHeader &glyph_header = StructAtOffset<GlyphHeader> (glyph_data, 0);
if (glyph_header.numberOfContours < 0)
{
const CompositeGlyphHeader *possible =
&StructAfter<CompositeGlyphHeader, GlyphHeader> (glyph_header);
iterator->glyph_start = glyph_data;
iterator->glyph_end = (const char *) glyph_data + length;
if (!iterator->in_range (possible))
return false;
iterator->current = possible;
return true;
}
return false;
}
DEFINE_SIZE_MIN (4);
};
struct accelerator_t
{
inline void init (hb_face_t *face)
{
hb_blob_t *head_blob = Sanitizer<head>().sanitize (face->reference_table (HB_OT_TAG_head));
const head *head_table = Sanitizer<head>::lock_instance (head_blob);
if ((unsigned int) head_table->indexToLocFormat > 1 || head_table->glyphDataFormat != 0)
{
/* Unknown format. Leave num_glyphs=0, that takes care of disabling us. */
hb_blob_destroy (head_blob);
return;
}
short_offset = 0 == head_table->indexToLocFormat;
hb_blob_destroy (head_blob);
loca_blob = Sanitizer<loca>().sanitize (face->reference_table (HB_OT_TAG_loca));
loca_table = Sanitizer<loca>::lock_instance (loca_blob);
glyf_blob = Sanitizer<glyf>().sanitize (face->reference_table (HB_OT_TAG_glyf));
glyf_table = Sanitizer<glyf>::lock_instance (glyf_blob);
num_glyphs = MAX (1u, hb_blob_get_length (loca_blob) / (short_offset ? 2 : 4)) - 1;
glyf_len = hb_blob_get_length (glyf_blob);
}
inline void fini (void)
{
hb_blob_destroy (loca_blob);
hb_blob_destroy (glyf_blob);
}
/*
* Returns true if the referenced glyph is a valid glyph and a composite glyph.
* If true is returned a pointer to the composite glyph will be written into
* composite.
*/
inline bool get_composite (hb_codepoint_t glyph,
CompositeGlyphHeader::Iterator *composite /* OUT */) const
{
unsigned int start_offset, end_offset;
if (!get_offsets (glyph, &start_offset, &end_offset))
return false; /* glyph not found */
return CompositeGlyphHeader::get_iterator ((const char*) this->glyf_table + start_offset,
end_offset - start_offset,
composite);
}
inline bool get_offsets (hb_codepoint_t glyph,
unsigned int *start_offset /* OUT */,
unsigned int *end_offset /* OUT */) const
{
if (unlikely (glyph >= num_glyphs))
return false;
if (short_offset)
{
const HBUINT16 *offsets = (const HBUINT16 *) loca_table->dataX;
*start_offset = 2 * offsets[glyph];
*end_offset = 2 * offsets[glyph + 1];
}
else
{
const HBUINT32 *offsets = (const HBUINT32 *) loca_table->dataX;
*start_offset = offsets[glyph];
*end_offset = offsets[glyph + 1];
}
if (*start_offset > *end_offset || *end_offset > glyf_len)
return false;
return true;
}
inline bool get_extents (hb_codepoint_t glyph,
hb_glyph_extents_t *extents) const
{
unsigned int start_offset, end_offset;
if (!get_offsets (glyph, &start_offset, &end_offset))
return false;
if (end_offset - start_offset < GlyphHeader::static_size)
return true; /* Empty glyph; zero extents. */
const GlyphHeader &glyph_header = StructAtOffset<GlyphHeader> (glyf_table, start_offset);
extents->x_bearing = MIN (glyph_header.xMin, glyph_header.xMax);
extents->y_bearing = MAX (glyph_header.yMin, glyph_header.yMax);
extents->width = MAX (glyph_header.xMin, glyph_header.xMax) - extents->x_bearing;
extents->height = MIN (glyph_header.yMin, glyph_header.yMax) - extents->y_bearing;
return true;
}
private:
bool short_offset;
unsigned int num_glyphs;
const loca *loca_table;
const glyf *glyf_table;
hb_blob_t *loca_blob;
hb_blob_t *glyf_blob;
unsigned int glyf_len;
};
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protected:
HBUINT8 dataX[VAR]; /* Glyphs data. */
DEFINE_SIZE_ARRAY (0, dataX);
};
} /* namespace OT */
#endif /* HB_OT_GLYF_TABLE_HH */