8aa83d97f9
"The values in the right class table are stored pre-multiplied by the number of bytes in a single kerning value, and the values in the left class table are stored pre-multiplied by the number of bytes in one row. This eliminates needing to multiply the row and column values together to determine the location of the kerning value. The array can be indexed by doing the right- and left-hand class mappings, adding the class values to the address of the array, and fetching the kerning value to which the new address points."
399 lines
11 KiB
C++
399 lines
11 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_KERN_TABLE_HH
|
|
#define HB_OT_KERN_TABLE_HH
|
|
|
|
#include "hb-open-type.hh"
|
|
|
|
/*
|
|
* kern -- Kerning
|
|
* https://docs.microsoft.com/en-us/typography/opentype/spec/kern
|
|
* https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6kern.html
|
|
*/
|
|
#define HB_OT_TAG_kern HB_TAG('k','e','r','n')
|
|
|
|
|
|
namespace OT {
|
|
|
|
|
|
struct hb_glyph_pair_t
|
|
{
|
|
hb_codepoint_t left;
|
|
hb_codepoint_t right;
|
|
};
|
|
|
|
struct KernPair
|
|
{
|
|
inline int get_kerning (void) const
|
|
{ return value; }
|
|
|
|
inline int cmp (const hb_glyph_pair_t &o) const
|
|
{
|
|
int ret = left.cmp (o.left);
|
|
if (ret) return ret;
|
|
return right.cmp (o.right);
|
|
}
|
|
|
|
inline bool sanitize (hb_sanitize_context_t *c) const
|
|
{
|
|
TRACE_SANITIZE (this);
|
|
return_trace (c->check_struct (this));
|
|
}
|
|
|
|
protected:
|
|
GlyphID left;
|
|
GlyphID right;
|
|
FWORD value;
|
|
public:
|
|
DEFINE_SIZE_STATIC (6);
|
|
};
|
|
|
|
struct KernSubTableFormat0
|
|
{
|
|
inline int get_kerning (hb_codepoint_t left, hb_codepoint_t right) const
|
|
{
|
|
hb_glyph_pair_t pair = {left, right};
|
|
int i = pairs.bsearch (pair);
|
|
if (i == -1)
|
|
return 0;
|
|
return pairs[i].get_kerning ();
|
|
}
|
|
|
|
inline bool sanitize (hb_sanitize_context_t *c) const
|
|
{
|
|
TRACE_SANITIZE (this);
|
|
return_trace (pairs.sanitize (c));
|
|
}
|
|
|
|
protected:
|
|
BinSearchArrayOf<KernPair> pairs; /* Array of kerning pairs. */
|
|
public:
|
|
DEFINE_SIZE_ARRAY (8, pairs);
|
|
};
|
|
|
|
struct KernClassTable
|
|
{
|
|
inline unsigned int get_class (hb_codepoint_t g) const { return classes[g - firstGlyph]; }
|
|
|
|
inline bool sanitize (hb_sanitize_context_t *c) const
|
|
{
|
|
TRACE_SANITIZE (this);
|
|
return_trace (firstGlyph.sanitize (c) && classes.sanitize (c));
|
|
}
|
|
|
|
protected:
|
|
HBUINT16 firstGlyph; /* First glyph in class range. */
|
|
ArrayOf<HBUINT16> classes; /* Glyph classes. */
|
|
public:
|
|
DEFINE_SIZE_ARRAY (4, classes);
|
|
};
|
|
|
|
struct KernSubTableFormat2
|
|
{
|
|
inline int get_kerning (hb_codepoint_t left, hb_codepoint_t right, const char *end) const
|
|
{
|
|
unsigned int l = (this+leftClassTable).get_class (left);
|
|
unsigned int r = (this+rightClassTable).get_class (right);
|
|
unsigned int offset = l + r;
|
|
const FWORD *arr = &(this+array);
|
|
if (unlikely ((const void *) arr < (const void *) this || (const void *) arr >= (const void *) end))
|
|
return 0;
|
|
const FWORD *v = &StructAtOffset<FWORD> (arr, offset);
|
|
if (unlikely ((const void *) v < (const void *) arr || (const void *) (v + 1) > (const void *) end))
|
|
return 0;
|
|
return *v;
|
|
}
|
|
|
|
inline bool sanitize (hb_sanitize_context_t *c) const
|
|
{
|
|
TRACE_SANITIZE (this);
|
|
return_trace (rowWidth.sanitize (c) &&
|
|
leftClassTable.sanitize (c, this) &&
|
|
rightClassTable.sanitize (c, this) &&
|
|
array.sanitize (c, this));
|
|
}
|
|
|
|
protected:
|
|
HBUINT16 rowWidth; /* The width, in bytes, of a row in the table. */
|
|
OffsetTo<KernClassTable>
|
|
leftClassTable; /* Offset from beginning of this subtable to
|
|
* left-hand class table. */
|
|
OffsetTo<KernClassTable>
|
|
rightClassTable;/* Offset from beginning of this subtable to
|
|
* right-hand class table. */
|
|
OffsetTo<FWORD>
|
|
array; /* Offset from beginning of this subtable to
|
|
* the start of the kerning array. */
|
|
public:
|
|
DEFINE_SIZE_MIN (8);
|
|
};
|
|
|
|
struct KernSubTable
|
|
{
|
|
inline int get_kerning (hb_codepoint_t left, hb_codepoint_t right, const char *end, unsigned int format) const
|
|
{
|
|
switch (format) {
|
|
case 0: return u.format0.get_kerning (left, right);
|
|
case 2: return u.format2.get_kerning (left, right, end);
|
|
default:return 0;
|
|
}
|
|
}
|
|
|
|
inline bool sanitize (hb_sanitize_context_t *c, unsigned int format) const
|
|
{
|
|
TRACE_SANITIZE (this);
|
|
switch (format) {
|
|
case 0: return_trace (u.format0.sanitize (c));
|
|
case 2: return_trace (u.format2.sanitize (c));
|
|
default:return_trace (true);
|
|
}
|
|
}
|
|
|
|
protected:
|
|
union {
|
|
KernSubTableFormat0 format0;
|
|
KernSubTableFormat2 format2;
|
|
} u;
|
|
public:
|
|
DEFINE_SIZE_MIN (0);
|
|
};
|
|
|
|
|
|
template <typename T>
|
|
struct KernSubTableWrapper
|
|
{
|
|
/* https://en.wikipedia.org/wiki/Curiously_recurring_template_pattern */
|
|
inline const T* thiz (void) const { return static_cast<const T *> (this); }
|
|
|
|
inline bool is_horizontal (void) const
|
|
{ return (thiz()->coverage & T::COVERAGE_CHECK_FLAGS) == T::COVERAGE_CHECK_HORIZONTAL; }
|
|
|
|
inline bool is_override (void) const
|
|
{ return bool (thiz()->coverage & T::COVERAGE_OVERRIDE_FLAG); }
|
|
|
|
inline int get_kerning (hb_codepoint_t left, hb_codepoint_t right, const char *end) const
|
|
{ return thiz()->subtable.get_kerning (left, right, end, thiz()->format); }
|
|
|
|
inline int get_h_kerning (hb_codepoint_t left, hb_codepoint_t right, const char *end) const
|
|
{ return is_horizontal () ? get_kerning (left, right, end) : 0; }
|
|
|
|
inline unsigned int get_size (void) const { return thiz()->length; }
|
|
|
|
inline bool sanitize (hb_sanitize_context_t *c) const
|
|
{
|
|
TRACE_SANITIZE (this);
|
|
return_trace (c->check_struct (thiz()) &&
|
|
thiz()->length >= T::min_size &&
|
|
c->check_array (thiz(), thiz()->length, 1) &&
|
|
thiz()->subtable.sanitize (c, thiz()->format));
|
|
}
|
|
};
|
|
|
|
template <typename T>
|
|
struct KernTable
|
|
{
|
|
/* https://en.wikipedia.org/wiki/Curiously_recurring_template_pattern */
|
|
inline const T* thiz (void) const { return static_cast<const T *> (this); }
|
|
|
|
inline int get_h_kerning (hb_codepoint_t left, hb_codepoint_t right, unsigned int table_length) const
|
|
{
|
|
int v = 0;
|
|
const typename T::SubTableWrapper *st = CastP<typename T::SubTableWrapper> (&thiz()->dataZ);
|
|
unsigned int count = thiz()->nTables;
|
|
for (unsigned int i = 0; i < count; i++)
|
|
{
|
|
if (st->is_override ())
|
|
v = 0;
|
|
v += st->get_h_kerning (left, right, table_length + (const char *) this);
|
|
st = &StructAfter<typename T::SubTableWrapper> (*st);
|
|
}
|
|
return v;
|
|
}
|
|
|
|
inline bool sanitize (hb_sanitize_context_t *c) const
|
|
{
|
|
TRACE_SANITIZE (this);
|
|
if (unlikely (!c->check_struct (thiz()) ||
|
|
thiz()->version != T::VERSION))
|
|
return_trace (false);
|
|
|
|
const typename T::SubTableWrapper *st = CastP<typename T::SubTableWrapper> (&thiz()->dataZ);
|
|
unsigned int count = thiz()->nTables;
|
|
for (unsigned int i = 0; i < count; i++)
|
|
{
|
|
if (unlikely (!st->sanitize (c)))
|
|
return_trace (false);
|
|
st = &StructAfter<typename T::SubTableWrapper> (*st);
|
|
}
|
|
|
|
return_trace (true);
|
|
}
|
|
};
|
|
|
|
struct KernOT : KernTable<KernOT>
|
|
{
|
|
friend struct KernTable<KernOT>;
|
|
|
|
static const uint16_t VERSION = 0x0000u;
|
|
|
|
struct SubTableWrapper : KernSubTableWrapper<SubTableWrapper>
|
|
{
|
|
friend struct KernSubTableWrapper<SubTableWrapper>;
|
|
|
|
enum coverage_flags_t {
|
|
COVERAGE_DIRECTION_FLAG = 0x01u,
|
|
COVERAGE_MINIMUM_FLAG = 0x02u,
|
|
COVERAGE_CROSSSTREAM_FLAG = 0x04u,
|
|
COVERAGE_OVERRIDE_FLAG = 0x08u,
|
|
|
|
COVERAGE_VARIATION_FLAG = 0x00u, /* Not supported. */
|
|
|
|
COVERAGE_CHECK_FLAGS = 0x07u,
|
|
COVERAGE_CHECK_HORIZONTAL = 0x01u
|
|
};
|
|
|
|
protected:
|
|
HBUINT16 versionZ; /* Unused. */
|
|
HBUINT16 length; /* Length of the subtable (including this header). */
|
|
HBUINT8 format; /* Subtable format. */
|
|
HBUINT8 coverage; /* Coverage bits. */
|
|
KernSubTable subtable; /* Subtable data. */
|
|
public:
|
|
DEFINE_SIZE_MIN (6);
|
|
};
|
|
|
|
protected:
|
|
HBUINT16 version; /* Version--0x0000u */
|
|
HBUINT16 nTables; /* Number of subtables in the kerning table. */
|
|
UnsizedArrayOf<HBUINT8> dataZ;
|
|
public:
|
|
DEFINE_SIZE_ARRAY (4, dataZ);
|
|
};
|
|
|
|
struct KernAAT : KernTable<KernAAT>
|
|
{
|
|
friend struct KernTable<KernAAT>;
|
|
|
|
static const uint32_t VERSION = 0x00010000u;
|
|
|
|
struct SubTableWrapper : KernSubTableWrapper<SubTableWrapper>
|
|
{
|
|
friend struct KernSubTableWrapper<SubTableWrapper>;
|
|
|
|
enum coverage_flags_t {
|
|
COVERAGE_DIRECTION_FLAG = 0x80u,
|
|
COVERAGE_CROSSSTREAM_FLAG = 0x40u,
|
|
COVERAGE_VARIATION_FLAG = 0x20u,
|
|
|
|
COVERAGE_OVERRIDE_FLAG = 0x00u, /* Not supported. */
|
|
|
|
COVERAGE_CHECK_FLAGS = 0xE0u,
|
|
COVERAGE_CHECK_HORIZONTAL = 0x00u
|
|
};
|
|
|
|
protected:
|
|
HBUINT32 length; /* Length of the subtable (including this header). */
|
|
HBUINT8 coverage; /* Coverage bits. */
|
|
HBUINT8 format; /* Subtable format. */
|
|
HBUINT16 tupleIndex; /* The tuple index (used for variations fonts).
|
|
* This value specifies which tuple this subtable covers. */
|
|
KernSubTable subtable; /* Subtable data. */
|
|
public:
|
|
DEFINE_SIZE_MIN (8);
|
|
};
|
|
|
|
protected:
|
|
HBUINT32 version; /* Version--0x00010000u */
|
|
HBUINT32 nTables; /* Number of subtables in the kerning table. */
|
|
UnsizedArrayOf<HBUINT8> dataZ;
|
|
public:
|
|
DEFINE_SIZE_ARRAY (8, dataZ);
|
|
};
|
|
|
|
struct kern
|
|
{
|
|
static const hb_tag_t tableTag = HB_OT_TAG_kern;
|
|
|
|
inline int get_h_kerning (hb_codepoint_t left, hb_codepoint_t right, unsigned int table_length) const
|
|
{
|
|
switch (u.major) {
|
|
case 0: return u.ot.get_h_kerning (left, right, table_length);
|
|
case 1: return u.aat.get_h_kerning (left, right, table_length);
|
|
default:return 0;
|
|
}
|
|
}
|
|
|
|
inline bool sanitize (hb_sanitize_context_t *c) const
|
|
{
|
|
TRACE_SANITIZE (this);
|
|
if (!u.major.sanitize (c)) return_trace (false);
|
|
switch (u.major) {
|
|
case 0: return_trace (u.ot.sanitize (c));
|
|
case 1: return_trace (u.aat.sanitize (c));
|
|
default:return_trace (true);
|
|
}
|
|
}
|
|
|
|
struct accelerator_t
|
|
{
|
|
inline void init (hb_face_t *face)
|
|
{
|
|
blob = hb_sanitize_context_t().reference_table<kern> (face);
|
|
table = blob->as<kern> ();
|
|
table_length = blob->length;
|
|
}
|
|
inline void fini (void)
|
|
{
|
|
hb_blob_destroy (blob);
|
|
}
|
|
|
|
inline int get_h_kerning (hb_codepoint_t left, hb_codepoint_t right) const
|
|
{ return table->get_h_kerning (left, right, table_length); }
|
|
|
|
private:
|
|
hb_blob_t *blob;
|
|
const kern *table;
|
|
unsigned int table_length;
|
|
};
|
|
|
|
protected:
|
|
union {
|
|
HBUINT16 major;
|
|
KernOT ot;
|
|
KernAAT aat;
|
|
} u;
|
|
public:
|
|
DEFINE_SIZE_UNION (2, major);
|
|
};
|
|
|
|
struct kern_accelerator_t : kern::accelerator_t {};
|
|
|
|
} /* namespace OT */
|
|
|
|
|
|
#endif /* HB_OT_KERN_TABLE_HH */
|