harfbuzz/src/hb-ot-var-hvar-table.hh

167 lines
4.6 KiB
C++

/*
* Copyright © 2017 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_VAR_HVAR_TABLE_HH
#define HB_OT_VAR_HVAR_TABLE_HH
#include "hb-ot-layout-common-private.hh"
namespace OT {
struct DeltaSetIndexMap
{
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (c->check_struct (this) &&
c->check_array (mapData, get_width (), mapCount));
}
unsigned int map (unsigned int v) const /* Returns 16.16 outer.inner. */
{
/* If count is zero, pass value unchanged. This takes
* care of direct mapping for advance map. */
if (!mapCount)
return v;
if (v >= mapCount)
v = mapCount - 1;
unsigned int u = 0;
{ /* Fetch it. */
unsigned int w = get_width ();
const HBUINT8 *p = mapData + w * v;
for (; w; w--)
u = (u << 8) + *p++;
}
{ /* Repack it. */
unsigned int n = get_inner_bitcount ();
unsigned int outer = u >> n;
unsigned int inner = u & ((1 << n) - 1);
u = (outer<<16) | inner;
}
return u;
}
protected:
inline unsigned int get_width (void) const
{ return ((format >> 4) & 3) + 1; }
inline unsigned int get_inner_bitcount (void) const
{ return (format & 0xF) + 1; }
protected:
HBUINT16 format; /* A packed field that describes the compressed
* representation of delta-set indices. */
HBUINT16 mapCount; /* The number of mapping entries. */
HBUINT8 mapData[VAR]; /* The delta-set index mapping data. */
public:
DEFINE_SIZE_ARRAY (4, mapData);
};
/*
* HVAR -- Horizontal Metrics Variations
* https://docs.microsoft.com/en-us/typography/opentype/spec/hvar
* VVAR -- Vertical Metrics Variations
* https://docs.microsoft.com/en-us/typography/opentype/spec/vvar
*/
#define HB_OT_TAG_HVAR HB_TAG('H','V','A','R')
#define HB_OT_TAG_VVAR HB_TAG('V','V','A','R')
struct HVARVVAR
{
static const hb_tag_t HVARTag = HB_OT_TAG_HVAR;
static const hb_tag_t VVARTag = HB_OT_TAG_VVAR;
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (version.sanitize (c) &&
likely (version.major == 1) &&
varStore.sanitize (c, this) &&
advMap.sanitize (c, this) &&
lsbMap.sanitize (c, this) &&
rsbMap.sanitize (c, this));
}
inline float get_advance_var (hb_codepoint_t glyph,
int *coords, unsigned int coord_count) const
{
unsigned int varidx = (this+advMap).map (glyph);
return (this+varStore).get_delta (varidx, coords, coord_count);
}
inline bool has_sidebearing_deltas (void) const
{ return lsbMap && rsbMap; }
protected:
FixedVersion<>version; /* Version of the metrics variation table
* initially set to 0x00010000u */
LOffsetTo<VariationStore>
varStore; /* Offset to item variation store table. */
LOffsetTo<DeltaSetIndexMap>
advMap; /* Offset to advance var-idx mapping. */
LOffsetTo<DeltaSetIndexMap>
lsbMap; /* Offset to lsb/tsb var-idx mapping. */
LOffsetTo<DeltaSetIndexMap>
rsbMap; /* Offset to rsb/bsb var-idx mapping. */
public:
DEFINE_SIZE_STATIC (20);
};
struct HVAR : HVARVVAR {
static const hb_tag_t tableTag = HB_OT_TAG_HVAR;
};
struct VVAR : HVARVVAR {
static const hb_tag_t tableTag = HB_OT_TAG_VVAR;
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (static_cast<const HVARVVAR *> (this)->sanitize (c) &&
vorgMap.sanitize (c, this));
}
protected:
LOffsetTo<DeltaSetIndexMap>
vorgMap; /* Offset to vertical-origin var-idx mapping. */
public:
DEFINE_SIZE_STATIC (24);
};
} /* namespace OT */
#endif /* HB_OT_VAR_HVAR_TABLE_HH */