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

246 lines
6.5 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_AVAR_TABLE_HH
#define HB_OT_VAR_AVAR_TABLE_HH
#include "hb-open-type.hh"
#include "hb-ot-var-common.hh"
/*
* avar -- Axis Variations
* https://docs.microsoft.com/en-us/typography/opentype/spec/avar
*/
#define HB_OT_TAG_avar HB_TAG('a','v','a','r')
namespace OT {
/* "Spec": https://github.com/be-fonts/boring-expansion-spec/issues/14 */
struct avarV2Tail
{
friend struct avar;
bool sanitize (hb_sanitize_context_t *c,
const void *base) const
{
TRACE_SANITIZE (this);
return_trace (varIdxMap.sanitize (c, base) &&
varStore.sanitize (c, base));
}
protected:
Offset32To<DeltaSetIndexMap> varIdxMap; /* Offset from the beginning of 'avar' table. */
Offset32To<VariationStore> varStore; /* Offset from the beginning of 'avar' table. */
public:
DEFINE_SIZE_STATIC (8);
};
struct AxisValueMap
{
bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (c->check_struct (this));
}
public:
F2DOT14 coords[2];
// F2DOT14 fromCoord; /* A normalized coordinate value obtained using
// * default normalization. */
// F2DOT14 toCoord; /* The modified, normalized coordinate value. */
public:
DEFINE_SIZE_STATIC (4);
};
struct SegmentMaps : Array16Of<AxisValueMap>
{
int map (int value, unsigned int from_offset = 0, unsigned int to_offset = 1) const
{
#define fromCoord coords[from_offset]
#define toCoord coords[to_offset]
/* The following special-cases are not part of OpenType, which requires
* that at least -1, 0, and +1 must be mapped. But we include these as
* part of a better error recovery scheme. */
if (len < 2)
{
if (!len)
return value;
else /* len == 1*/
return value - arrayZ[0].fromCoord + arrayZ[0].toCoord;
}
if (value <= arrayZ[0].fromCoord)
return value - arrayZ[0].fromCoord + arrayZ[0].toCoord;
unsigned int i;
unsigned int count = len - 1;
for (i = 1; i < count && value > arrayZ[i].fromCoord; i++)
;
if (value >= arrayZ[i].fromCoord)
return value - arrayZ[i].fromCoord + arrayZ[i].toCoord;
if (unlikely (arrayZ[i-1].fromCoord == arrayZ[i].fromCoord))
return arrayZ[i-1].toCoord;
int denom = arrayZ[i].fromCoord - arrayZ[i-1].fromCoord;
return roundf (arrayZ[i-1].toCoord + ((float) (arrayZ[i].toCoord - arrayZ[i-1].toCoord) *
(value - arrayZ[i-1].fromCoord)) / denom);
#undef toCoord
#undef fromCoord
}
int unmap (int value) const { return map (value, 1, 0); }
public:
DEFINE_SIZE_ARRAY (2, *this);
};
struct avar
{
static constexpr hb_tag_t tableTag = HB_OT_TAG_avar;
bool has_data () const { return version.to_int (); }
const SegmentMaps* get_segment_maps () const
{ return &firstAxisSegmentMaps; }
unsigned get_axis_count () const
{ return axisCount; }
bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
if (!(version.sanitize (c) &&
(version.major == 1
#ifndef HB_NO_VARIATIONS2
|| version.major == 2
#endif
) &&
c->check_struct (this)))
return_trace (false);
const SegmentMaps *map = &firstAxisSegmentMaps;
unsigned int count = axisCount;
for (unsigned int i = 0; i < count; i++)
{
if (unlikely (!map->sanitize (c)))
return_trace (false);
map = &StructAfter<SegmentMaps> (*map);
}
#ifndef HB_NO_VARIATIONS2
if (version.major < 2)
return_trace (true);
const auto &v2 = * (const avarV2Tail *) map;
if (unlikely (!v2.sanitize (c, this)))
return_trace (false);
#endif
return_trace (true);
}
void map_coords (int *coords, unsigned int coords_length) const
{
unsigned int count = hb_min (coords_length, axisCount);
const SegmentMaps *map = &firstAxisSegmentMaps;
for (unsigned int i = 0; i < count; i++)
{
coords[i] = map->map (coords[i]);
map = &StructAfter<SegmentMaps> (*map);
}
#ifndef HB_NO_VARIATIONS2
if (version.major < 2)
return;
for (; count < axisCount; count++)
map = &StructAfter<SegmentMaps> (*map);
const auto &v2 = * (const avarV2Tail *) map;
const auto &varidx_map = this+v2.varIdxMap;
const auto &var_store = this+v2.varStore;
auto *var_store_cache = var_store.create_cache ();
hb_vector_t<int> out;
out.alloc (coords_length);
for (unsigned i = 0; i < coords_length; i++)
{
int v = coords[i];
uint32_t varidx = varidx_map.map (i);
float delta = var_store.get_delta (varidx, coords, coords_length, var_store_cache);
v += roundf (delta);
v = hb_clamp (v, -(1<<14), +(1<<14));
out.push (v);
}
OT::VariationStore::destroy_cache (var_store_cache);
for (unsigned i = 0; i < coords_length; i++)
coords[i] = out[i];
#endif
}
void unmap_coords (int *coords, unsigned int coords_length) const
{
unsigned int count = hb_min (coords_length, axisCount);
const SegmentMaps *map = &firstAxisSegmentMaps;
for (unsigned int i = 0; i < count; i++)
{
coords[i] = map->unmap (coords[i]);
map = &StructAfter<SegmentMaps> (*map);
}
}
protected:
FixedVersion<>version; /* Version of the avar table
* initially set to 0x00010000u */
HBUINT16 reserved; /* This field is permanently reserved. Set to 0. */
HBUINT16 axisCount; /* The number of variation axes in the font. This
* must be the same number as axisCount in the
* 'fvar' table. */
SegmentMaps firstAxisSegmentMaps;
public:
DEFINE_SIZE_MIN (8);
};
} /* namespace OT */
#endif /* HB_OT_VAR_AVAR_TABLE_HH */