harfbuzz/src/hb-aat-layout-bsln-table.hh

159 lines
4.5 KiB
C++

/*
* Copyright © 2018 Ebrahim Byagowi
*
* 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.
*/
#ifndef HB_AAT_LAYOUT_BSLN_TABLE_HH
#define HB_AAT_LAYOUT_BSLN_TABLE_HH
#include "hb-aat-layout-common.hh"
/*
* bsln -- Baseline
* https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6bsln.html
*/
#define HB_AAT_TAG_bsln HB_TAG('b','s','l','n')
namespace AAT {
struct BaselineTableFormat0Part
{
bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (likely (c->check_struct (this)));
}
protected:
// Roman, Ideographic centered, Ideographic low, Hanging and Math
// are the default defined ones, but any other maybe accessed also.
HBINT16 deltas[32]; /* These are the FUnit distance deltas from
* the font's natural baseline to the other
* baselines used in the font. */
public:
DEFINE_SIZE_STATIC (64);
};
struct BaselineTableFormat1Part
{
bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (likely (c->check_struct (this) &&
lookupTable.sanitize (c)));
}
protected:
HBINT16 deltas[32]; /* ditto */
Lookup<HBUINT16>
lookupTable; /* Lookup table that maps glyphs to their
* baseline values. */
public:
DEFINE_SIZE_MIN (66);
};
struct BaselineTableFormat2Part
{
bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (likely (c->check_struct (this)));
}
protected:
HBGlyphID16 stdGlyph; /* The specific glyph index number in this
* font that is used to set the baseline values.
* This is the standard glyph.
* This glyph must contain a set of control points
* (whose numbers are contained in the ctlPoints field)
* that are used to determine baseline distances. */
HBUINT16 ctlPoints[32]; /* Set of control point numbers,
* associated with the standard glyph.
* A value of 0xFFFF means there is no corresponding
* control point in the standard glyph. */
public:
DEFINE_SIZE_STATIC (66);
};
struct BaselineTableFormat3Part
{
bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (likely (c->check_struct (this) && lookupTable.sanitize (c)));
}
protected:
HBGlyphID16 stdGlyph; /* ditto */
HBUINT16 ctlPoints[32]; /* ditto */
Lookup<HBUINT16>
lookupTable; /* Lookup table that maps glyphs to their
* baseline values. */
public:
DEFINE_SIZE_MIN (68);
};
struct bsln
{
static constexpr hb_tag_t tableTag = HB_AAT_TAG_bsln;
bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
if (unlikely (!(c->check_struct (this) && defaultBaseline < 32)))
return_trace (false);
switch (format)
{
case 0: return_trace (parts.format0.sanitize (c));
case 1: return_trace (parts.format1.sanitize (c));
case 2: return_trace (parts.format2.sanitize (c));
case 3: return_trace (parts.format3.sanitize (c));
default:return_trace (true);
}
}
protected:
FixedVersion<>version; /* Version number of the Baseline table. */
HBUINT16 format; /* Format of the baseline table. Only one baseline
* format may be selected for the font. */
HBUINT16 defaultBaseline;/* Default baseline value for all glyphs.
* This value can be from 0 through 31. */
union {
// Distance-Based Formats
BaselineTableFormat0Part format0;
BaselineTableFormat1Part format1;
// Control Point-based Formats
BaselineTableFormat2Part format2;
BaselineTableFormat3Part format3;
} parts;
public:
DEFINE_SIZE_MIN (8);
};
} /* namespace AAT */
#endif /* HB_AAT_LAYOUT_BSLN_TABLE_HH */