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[GX] Add VariationAlternates, to allow conditional lookups in GSUB/GPOS

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Not hooked up to runtime yet.
This commit is contained in:
Behdad Esfahbod 2016-03-12 23:49:09 -08:00
parent 976eeb8e02
commit 71b06fd392
2 changed files with 98 additions and 2 deletions
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1
src/hb-open-type-private.hh
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@ -630,6 +630,7 @@ struct IntType
inline operator Type(void) const { return v; }
inline bool operator == (const IntType<Type,Size> &o) const { return (Type) v == (Type) o.v; }
inline bool operator != (const IntType<Type,Size> &o) const { return !(*this == o); }
inline unsigned int get_size (void) const { return Size; }
static inline int cmp (const IntType<Type,Size> *a, const IntType<Type,Size> *b) { return b->cmp (*a); }
inline int cmp (Type a) const
{

99
src/hb-ot-layout-common-private.hh
View File

@ -575,6 +575,7 @@ struct LookupFlag : USHORT
IgnoreMarks = 0x0008u,
IgnoreFlags = 0x000Eu,
UseMarkFilteringSet = 0x0010u,
UseVariationAlternates= 0x0020u,
Reserved = 0x00E0u,
MarkAttachmentType = 0xFF00u
};
@ -587,6 +588,88 @@ struct LookupFlag : USHORT
HB_MARK_AS_FLAG_T (OT::LookupFlag::Flags);
namespace OT {
struct VariationGridAxis
{
inline int locate (int *coords, unsigned int coord_len) const
{
int coord = axisIndex < coord_len ? coords[axisIndex] : 0;
unsigned int count = axisCoords.len;
unsigned int i = 0;
while (i + 1 < count && coord < axisCoords[i + 1])
i++;
return axisCoords[i] <= coord ? i : -1;
}
inline unsigned int get_len (void) const
{
return axisCoords.len - 1;
}
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (c->check_struct (this) && axisCoords.sanitize (c));
}
Index axisIndex;
SortedArrayOf<F2DOT14> axisCoords;
public:
DEFINE_SIZE_ARRAY (4, axisCoords);
};
struct VariationGrid
{
inline int locate (int *coords, unsigned int coord_len) const
{
int location = 0;
unsigned int count = axes.len;
for (unsigned int i = 0; i < count; i++)
{
const VariationGridAxis &axis = (this+axes[i]);
int axisLoc = axis.locate (coords, coord_len);
if (axisLoc == -1)
return -1;
location = location * (axis.get_len () - 1) + axisLoc; /* XXX Check for overflow?. */
}
return location;
}
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (axes.sanitize (c, this));
}
OffsetArrayOf<VariationGridAxis>
axes;
public:
DEFINE_SIZE_ARRAY (2, axes);
};
struct VariationAlternates
{
inline unsigned int get_lookup_index (int *coords, unsigned int coord_len) const
{
int location = (this+grid).locate (coords, coord_len);
if (location == -1)
return 0xFFFE; /* TODO: give it a name. */
return lookupIndex[location];
}
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (grid.sanitize (c, this) && lookupIndex.sanitize (c));
}
OffsetTo<VariationGrid> grid;
IndexArray lookupIndex;
public:
DEFINE_SIZE_ARRAY (4, lookupIndex);
};
struct Lookup
{
inline unsigned int get_subtable_count (void) const { return subTable.len; }
@ -655,10 +738,17 @@ struct Lookup
TRACE_SANITIZE (this);
/* Real sanitize of the subtables is done by GSUB/GPOS/... */
if (!(c->check_struct (this) && subTable.sanitize (c))) return_trace (false);
const void *cursor = &StructAfter<char> (subTable);
if (lookupFlag & LookupFlag::UseMarkFilteringSet)
{
const USHORT &markFilteringSet = StructAfter<USHORT> (subTable);
const USHORT &markFilteringSet = CastR<USHORT> (cursor);
if (!markFilteringSet.sanitize (c)) return_trace (false);
cursor = &StructAfter<char> (markFilteringSet);
}
if (lookupFlag & LookupFlag::UseVariationAlternates)
{
const OffsetTo<VariationAlternates,ULONG> &varAlts = CastR<const OffsetTo<VariationAlternates,ULONG> > (cursor);
if (!varAlts.sanitize (c, this)) return_trace (false);
}
return_trace (true);
}
@ -671,8 +761,13 @@ struct Lookup
USHORT markFilteringSetX[VAR]; /* Index (base 0) into GDEF mark glyph sets
* structure. This field is only present if bit
* UseMarkFilteringSet of lookup flags is set. */
OffsetTo<VariationAlternates,ULONG>
variationAlternatesZ[VAR];
/* Index (base 0) into GDEF mark glyph sets
* structure. This field is only present if bit
* UseMarkFilteringSet of lookup flags is set. */
public:
DEFINE_SIZE_ARRAY2 (6, subTable, markFilteringSetX);
DEFINE_SIZE_MIN (6);
};
typedef OffsetListOf<Lookup> LookupList;