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harfbuzz/src/hb-ot-glyf-table.hh

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/*
* Copyright © 2015 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
* Adobe Author(s): Michiharu Ariza
*/
#ifndef HB_OT_GLYF_TABLE_HH
#define HB_OT_GLYF_TABLE_HH
#include "hb-open-type.hh"
#include "hb-ot-head-table.hh"
#include "hb-ot-hmtx-table.hh"
#include "hb-ot-var-gvar-table.hh"
#include "hb-subset-glyf.hh"
namespace OT {
/*
* loca -- Index to Location
* https://docs.microsoft.com/en-us/typography/opentype/spec/loca
*/
#define HB_OT_TAG_loca HB_TAG('l','o','c','a')
struct loca
{
friend struct glyf;
static constexpr hb_tag_t tableTag = HB_OT_TAG_loca;
bool sanitize (hb_sanitize_context_t *c HB_UNUSED) const
{
TRACE_SANITIZE (this);
return_trace (true);
}
protected:
UnsizedArrayOf<HBUINT8> dataZ; /* Location data. */
public:
DEFINE_SIZE_MIN (0); /* In reality, this is UNBOUNDED() type; but since we always
* check the size externally, allow Null() object of it by
* defining it MIN() instead. */
};
/*
* glyf -- TrueType Glyph Data
* https://docs.microsoft.com/en-us/typography/opentype/spec/glyf
*/
#define HB_OT_TAG_glyf HB_TAG('g','l','y','f')
struct glyf
{
static constexpr hb_tag_t tableTag = HB_OT_TAG_glyf;
bool sanitize (hb_sanitize_context_t *c HB_UNUSED) const
{
TRACE_SANITIZE (this);
/* We don't check for anything specific here. The users of the
* struct do all the hard work... */
return_trace (true);
}
bool subset (hb_subset_plan_t *plan) const
{
hb_blob_t *glyf_prime = nullptr;
hb_blob_t *loca_prime = nullptr;
bool success = true;
bool use_short_loca = false;
if (hb_subset_glyf_and_loca (plan, &use_short_loca, &glyf_prime, &loca_prime)) {
success = success && plan->add_table (HB_OT_TAG_glyf, glyf_prime);
success = success && plan->add_table (HB_OT_TAG_loca, loca_prime);
success = success && _add_head_and_set_loca_version (plan, use_short_loca);
} else {
success = false;
}
hb_blob_destroy (loca_prime);
hb_blob_destroy (glyf_prime);
return success;
}
static bool
_add_head_and_set_loca_version (hb_subset_plan_t *plan, bool use_short_loca)
{
hb_blob_t *head_blob = hb_sanitize_context_t ().reference_table<head> (plan->source);
hb_blob_t *head_prime_blob = hb_blob_copy_writable_or_fail (head_blob);
hb_blob_destroy (head_blob);
if (unlikely (!head_prime_blob))
return false;
head *head_prime = (head *) hb_blob_get_data_writable (head_prime_blob, nullptr);
head_prime->indexToLocFormat.set (use_short_loca ? 0 : 1);
bool success = plan->add_table (HB_OT_TAG_head, head_prime_blob);
hb_blob_destroy (head_prime_blob);
return success;
}
struct GlyphHeader
{
HBINT16 numberOfContours; /* If the number of contours is
* greater than or equal to zero,
* this is a simple glyph; if negative,
* this is a composite glyph. */
FWORD xMin; /* Minimum x for coordinate data. */
FWORD yMin; /* Minimum y for coordinate data. */
FWORD xMax; /* Maximum x for coordinate data. */
FWORD yMax; /* Maximum y for coordinate data. */
DEFINE_SIZE_STATIC (10);
};
struct CompositeGlyphHeader
{
enum composite_glyph_flag_t {
ARG_1_AND_2_ARE_WORDS = 0x0001,
ARGS_ARE_XY_VALUES = 0x0002,
ROUND_XY_TO_GRID = 0x0004,
WE_HAVE_A_SCALE = 0x0008,
MORE_COMPONENTS = 0x0020,
WE_HAVE_AN_X_AND_Y_SCALE = 0x0040,
WE_HAVE_A_TWO_BY_TWO = 0x0080,
WE_HAVE_INSTRUCTIONS = 0x0100,
USE_MY_METRICS = 0x0200,
OVERLAP_COMPOUND = 0x0400,
SCALED_COMPONENT_OFFSET = 0x0800,
UNSCALED_COMPONENT_OFFSET = 0x1000
};
HBUINT16 flags;
GlyphID glyphIndex;
unsigned int get_size () const
{
unsigned int size = min_size;
// arg1 and 2 are int16
if (flags & ARG_1_AND_2_ARE_WORDS) size += 4;
// arg1 and 2 are int8
else size += 2;
// One x 16 bit (scale)
if (flags & WE_HAVE_A_SCALE) size += 2;
// Two x 16 bit (xscale, yscale)
else if (flags & WE_HAVE_AN_X_AND_Y_SCALE) size += 4;
// Four x 16 bit (xscale, scale01, scale10, yscale)
else if (flags & WE_HAVE_A_TWO_BY_TWO) size += 8;
return size;
}
void transform_point (float &x, float &y) const
{
int tx, ty;
const HBINT8 *p = &StructAfter<const HBINT8> (glyphIndex);
if (flags & ARG_1_AND_2_ARE_WORDS)
{
tx = *(const HBINT16 *)p;
p += HBINT16::static_size;
ty = *(const HBINT16 *)p;
p += HBINT16::static_size;
}
else
{
tx = *p++;
ty = *p++;
}
if (!(flags & ARGS_ARE_XY_VALUES)) tx = ty = 0; /* TODO: anchor point unsupported for now */
if (flags & WE_HAVE_A_SCALE)
{
float scale = ((const F2DOT14*)p)->to_float ();
x *= scale;
y *= scale;
}
else if (flags & WE_HAVE_AN_X_AND_Y_SCALE)
{
x *= ((const F2DOT14*)p)[0].to_float ();
y *= ((const F2DOT14*)p)[1].to_float ();
}
else if (flags & WE_HAVE_A_TWO_BY_TWO)
{
float x_ = x * ((const F2DOT14*)p)[0].to_float () + y * ((const F2DOT14*)p)[1].to_float ();
y = x * ((const F2DOT14*)p)[2].to_float () + y * ((const F2DOT14*)p)[3].to_float ();
x = x_;
}
if (tx | ty) { x += tx; y += ty; }
}
struct Iterator
{
const char *glyph_start;
const char *glyph_end;
const CompositeGlyphHeader *current;
bool move_to_next ()
{
if (current->flags & CompositeGlyphHeader::MORE_COMPONENTS)
{
const CompositeGlyphHeader *possible =
&StructAfter<CompositeGlyphHeader, CompositeGlyphHeader> (*current);
if (unlikely (!in_range (possible))) return false;
current = possible;
return true;
}
return false;
}
bool in_range (const CompositeGlyphHeader *composite) const
{
return (const char *) composite >= glyph_start
&& ((const char *) composite + CompositeGlyphHeader::min_size) <= glyph_end
&& ((const char *) composite + composite->get_size ()) <= glyph_end;
}
};
static bool get_iterator (const char * glyph_data,
unsigned int length,
CompositeGlyphHeader::Iterator *iterator /* OUT */)
{
if (length < GlyphHeader::static_size)
return false; /* Empty glyph; zero extents. */
const GlyphHeader &glyph_header = StructAtOffset<GlyphHeader> (glyph_data, 0);
if (glyph_header.numberOfContours < 0)
{
const CompositeGlyphHeader *possible =
&StructAfter<CompositeGlyphHeader, GlyphHeader> (glyph_header);
iterator->glyph_start = glyph_data;
iterator->glyph_end = (const char *) glyph_data + length;
if (!iterator->in_range (possible))
return false;
iterator->current = possible;
return true;
}
return false;
}
DEFINE_SIZE_MIN (4);
};
struct accelerator_t
{
void init (hb_face_t *face)
{
memset (this, 0, sizeof (accelerator_t));
const OT::head &head = *face->table.head;
if (head.indexToLocFormat > 1 || head.glyphDataFormat != 0)
/* Unknown format. Leave num_glyphs=0, that takes care of disabling us. */
return;
short_offset = 0 == head.indexToLocFormat;
loca_table = hb_sanitize_context_t ().reference_table<loca> (face);
glyf_table = hb_sanitize_context_t ().reference_table<glyf> (face);
num_glyphs = MAX (1u, loca_table.get_length () / (short_offset ? 2 : 4)) - 1;
gvar_accel.init (face);
hmtx_accel.init (face);
vmtx_accel.init (face);
}
void fini ()
{
loca_table.destroy ();
glyf_table.destroy ();
gvar_accel.fini ();
hmtx_accel.fini ();
vmtx_accel.fini ();
}
/*
* Returns true if the referenced glyph is a valid glyph and a composite glyph.
* If true is returned a pointer to the composite glyph will be written into
* composite.
*/
bool get_composite (hb_codepoint_t glyph,
CompositeGlyphHeader::Iterator *composite /* OUT */) const
{
if (unlikely (!num_glyphs))
return false;
unsigned int start_offset, end_offset;
if (!get_offsets (glyph, &start_offset, &end_offset))
return false; /* glyph not found */
return CompositeGlyphHeader::get_iterator ((const char *) this->glyf_table + start_offset,
end_offset - start_offset,
composite);
}
enum simple_glyph_flag_t {
FLAG_ON_CURVE = 0x01,
FLAG_X_SHORT = 0x02,
FLAG_Y_SHORT = 0x04,
FLAG_REPEAT = 0x08,
FLAG_X_SAME = 0x10,
FLAG_Y_SAME = 0x20,
FLAG_RESERVED1 = 0x40,
FLAG_RESERVED2 = 0x80
};
enum phantom_point_index_t {
PHANTOM_LEFT = 0,
PHANTOM_RIGHT = 1,
PHANTOM_TOP = 2,
PHANTOM_BOTTOM = 3,
PHANTOM_COUNT = 4
};
protected:
const GlyphHeader &get_header (hb_codepoint_t glyph) const
{
unsigned int start_offset, end_offset;
if (!get_offsets (glyph, &start_offset, &end_offset) || end_offset - start_offset < GlyphHeader::static_size)
return Null(GlyphHeader);
return StructAtOffset<GlyphHeader> (glyf_table, start_offset);
}
struct x_setter_t
{
void set (contour_point_t &point, float v) const { point.x = v; }
bool is_short (uint8_t flag) const { return (flag & FLAG_X_SHORT) != 0; }
bool is_same (uint8_t flag) const { return (flag & FLAG_X_SAME) != 0; }
};
struct y_setter_t
{
void set (contour_point_t &point, float v) const { point.y = v; }
bool is_short (uint8_t flag) const { return (flag & FLAG_Y_SHORT) != 0; }
bool is_same (uint8_t flag) const { return (flag & FLAG_Y_SAME) != 0; }
};
template <typename T>
static bool read_points (const HBUINT8 *&p /* IN/OUT */,
hb_vector_t<contour_point_t> &points_ /* IN/OUT */,
const range_checker_t &checker)
{
T coord_setter;
float v = 0;
for (unsigned int i = 0; i < points_.length - PHANTOM_COUNT; i++)
{
uint8_t flag = points_[i].flag;
if (coord_setter.is_short (flag))
{
if (unlikely (!checker.in_range (p))) return false;
if (coord_setter.is_same (flag))
v += *p++;
else
v -= *p++;
}
else
{
if (!coord_setter.is_same (flag))
{
if (unlikely (!checker.in_range ((const HBUINT16 *)p))) return false;
v += *(const HBINT16 *)p;
p += HBINT16::static_size;
}
}
coord_setter.set (points_[i], v);
}
return true;
}
void init_phantom_points (hb_codepoint_t glyph, hb_array_t<contour_point_t> &phantoms /* IN/OUT */) const
{
const GlyphHeader &header = get_header (glyph);
int h_delta = (int)header.xMin - hmtx_accel.get_side_bearing (glyph);
int v_delta = (int)header.yMax - vmtx_accel.get_side_bearing (glyph);
unsigned int h_adv = hmtx_accel.get_advance (glyph);
unsigned int v_adv = vmtx_accel.get_advance (glyph);
phantoms[PHANTOM_LEFT].x = h_delta;
phantoms[PHANTOM_RIGHT].x = h_adv + h_delta;
phantoms[PHANTOM_TOP].y = v_delta;
phantoms[PHANTOM_BOTTOM].y = -v_adv + v_delta;
}
/* for a simple glyph, return contour end points, flags, along with coordinate points
* for a composite glyph, return pseudo component points
* in both cases points trailed with four phantom points
*/
bool get_contour_points (hb_codepoint_t glyph,
hb_vector_t<contour_point_t> &points_ /* OUT */,
hb_vector_t<unsigned int> &end_points_ /* OUT */,
const bool phantom_only=false) const
{
unsigned int num_points = 0;
unsigned int start_offset, end_offset;
if (unlikely (!get_offsets (glyph, &start_offset, &end_offset))) return false;
if (unlikely (end_offset - start_offset < GlyphHeader::static_size))
{
/* empty glyph */
points_.resize (PHANTOM_COUNT);
for (unsigned int i = 0; i < points_.length; i++) points_[i].init ();
return true;
}
CompositeGlyphHeader::Iterator composite;
if (get_composite (glyph, &composite))
{
/* For a composite glyph, add one pseudo point for each component */
do { num_points++; } while (composite.move_to_next());
points_.resize (num_points + PHANTOM_COUNT);
for (unsigned int i = 0; i < points_.length; i++) points_[i].init ();
return true;
}
const GlyphHeader &glyph_header = StructAtOffset<GlyphHeader> (glyf_table, start_offset);
int16_t num_contours = (int16_t) glyph_header.numberOfContours;
const HBUINT16 *end_pts = &StructAfter<HBUINT16, GlyphHeader> (glyph_header);
range_checker_t checker (glyf_table, start_offset, end_offset);
num_points = 0;
if (num_contours > 0)
{
if (unlikely (!checker.in_range (&end_pts[num_contours + 1]))) return false;
num_points = end_pts[num_contours - 1] + 1;
}
else if (num_contours < 0)
{
CompositeGlyphHeader::Iterator composite;
if (unlikely (!get_composite (glyph, &composite))) return false;
do
{
num_points++;
} while (composite.move_to_next());
}
points_.resize (num_points + PHANTOM_COUNT);
for (unsigned int i = 0; i < points_.length; i++) points_[i].init ();
if ((num_contours <= 0) || phantom_only) return true;
/* Read simple glyph points if !phantom_only */
end_points_.resize (num_contours);
for (int16_t i = 0; i < num_contours; i++)
end_points_[i] = end_pts[i];
/* Skip instructions */
const HBUINT8 *p = &StructAtOffset<HBUINT8> (&end_pts[num_contours+1], end_pts[num_contours]);
/* Read flags */
for (unsigned int i = 0; i < num_points; i++)
{
if (unlikely (!checker.in_range (p))) return false;
uint8_t flag = *p++;
points_[i].flag = flag;
if ((flag & FLAG_REPEAT) != 0)
{
if (unlikely (!checker.in_range (p))) return false;
unsigned int repeat_count = *p++;
while ((repeat_count-- > 0) && (++i < num_points))
points_[i].flag = flag;
}
}
/* Read x & y coordinates */
return (read_points<x_setter_t> (p, points_, checker) &&
read_points<y_setter_t> (p, points_, checker));
}
/* Note: Recursively calls itself. Who's checking recursively nested composite glyph BTW? */
bool get_var_metrics (hb_codepoint_t glyph,
const int *coords, unsigned int coord_count,
hb_array_t<contour_point_t> phantoms /* OUT */) const
{
hb_vector_t<contour_point_t> points;
hb_vector_t<unsigned int> end_points;
if (unlikely (!get_contour_points (glyph, points, end_points, true/*phantom_only*/))) return false;
hb_array_t<contour_point_t> phantoms_array = points.sub_array (points.length-PHANTOM_COUNT, PHANTOM_COUNT);
init_phantom_points (glyph, phantoms_array);
if (unlikely (!gvar_accel.apply_deltas_to_points (glyph, coords, coord_count,
points.as_array (), end_points.as_array ()))) return false;
for (unsigned int i = 0; i < PHANTOM_COUNT; i++)
phantoms[i] = points[points.length - PHANTOM_COUNT + i];
CompositeGlyphHeader::Iterator composite;
if (!get_composite (glyph, &composite)) return true; /* simple glyph */
do
{
if (composite.current->flags & CompositeGlyphHeader::USE_MY_METRICS)
{
if (unlikely (!get_var_metrics (composite.current->glyphIndex, coords, coord_count,
phantoms.sub_array (0, 2)))) return false;
for (unsigned int j = 0; j < phantoms.length; j++)
composite.current->transform_point (phantoms[j].x, phantoms[j].y);
}
} while (composite.move_to_next());
return true;
}
struct contour_bounds_t
{
contour_bounds_t () { min.x = min.y = FLT_MAX; max.x = max.y = FLT_MIN; }
void add (const contour_point_t &p)
{
min.x = MIN (min.x, p.x);
min.y = MIN (min.y, p.y);
max.x = MAX (max.x, p.x);
max.y = MAX (max.y, p.y);
}
void offset (const contour_point_t &p) { min.offset (p); max.offset (p); }
void merge (const contour_bounds_t &b)
{
if (empty ()) { *this = b; return; }
add (b.min);
add (b.max);
}
bool empty () const { return (min.x >= max.x) || (min.y >= max.y); }
contour_point_t min;
contour_point_t max;
};
/* Note: Recursively calls itself. Who's checking recursively nested composite glyph BTW? */
bool get_bounds_var (hb_codepoint_t glyph,
const int *coords, unsigned int coord_count,
contour_bounds_t &bounds) const
{
hb_vector_t<contour_point_t> points;
hb_vector_t<unsigned int> end_points;
if (unlikely (!get_contour_points (glyph, points, end_points))) return false;
hb_array_t<contour_point_t> phantoms_array = points.sub_array (points.length-PHANTOM_COUNT, PHANTOM_COUNT);
init_phantom_points (glyph, phantoms_array);
if (unlikely (!gvar_accel.apply_deltas_to_points (glyph, coords, coord_count, points.as_array (), end_points.as_array ()))) return false;
unsigned int comp_index = 0;
CompositeGlyphHeader::Iterator composite;
if (!get_composite (glyph, &composite))
{
/* simple glyph */
for (unsigned int i = 0; i + PHANTOM_COUNT < points.length; i++)
bounds.add (points[i]); /* TODO: need to check ON_CURVE or flatten? */
}
else
{
/* composite glyph */
do
{
contour_bounds_t comp_bounds;
if (unlikely (!get_bounds_var (composite.current->glyphIndex, coords, coord_count, comp_bounds))) return false;
/* Apply offset & scaling */
composite.current->transform_point (comp_bounds.min.x, comp_bounds.min.y);
composite.current->transform_point (comp_bounds.max.x, comp_bounds.max.y);
/* Apply offset adjustments from gvar */
comp_bounds.offset (points[comp_index]);
bounds.merge (comp_bounds);
comp_index++;
} while (composite.move_to_next());
}
/* Shift bounds by the updated left side bearing (vertically too?) */
{
float x_delta = points[points.length - PHANTOM_COUNT + PHANTOM_LEFT].x;
bounds.min.x -= x_delta;
bounds.max.x -= x_delta;
}
return true;
}
bool get_extents_var (hb_codepoint_t glyph,
const int *coords, unsigned int coord_count,
hb_glyph_extents_t *extents) const
{
contour_bounds_t bounds;
if (unlikely (!get_bounds_var (glyph, coords, coord_count, bounds))) return false;
if (bounds.min.x >= bounds.max.x)
{
extents->width = 0;
extents->x_bearing = 0;
}
else
{
extents->x_bearing = (int32_t)floorf (bounds.min.x);
extents->width = (int32_t)ceilf (bounds.max.x) - extents->x_bearing;
}
if (bounds.min.y >= bounds.max.y)
{
extents->height = 0;
extents->y_bearing = 0;
}
else
{
extents->y_bearing = (int32_t)ceilf (bounds.max.y);
extents->height = (int32_t)floorf (bounds.min.y) - extents->y_bearing;
}
return true;
}
public:
/* based on FontTools _g_l_y_f.py::trim */
bool remove_padding (unsigned int start_offset,
unsigned int *end_offset) const
{
if (*end_offset - start_offset < GlyphHeader::static_size) return true;
const char *glyph = ((const char *) glyf_table) + start_offset;
const char * const glyph_end = glyph + (*end_offset - start_offset);
const GlyphHeader &glyph_header = StructAtOffset<GlyphHeader> (glyph, 0);
int16_t num_contours = (int16_t) glyph_header.numberOfContours;
if (num_contours < 0)
/* Trimming for composites not implemented.
* If removing hints it falls out of that. */
return true;
else if (num_contours > 0)
{
/* simple glyph w/contours, possibly trimmable */
glyph += GlyphHeader::static_size + 2 * num_contours;
if (unlikely (glyph + 2 >= glyph_end)) return false;
uint16_t nCoordinates = (uint16_t) StructAtOffset<HBUINT16> (glyph - 2, 0) + 1;
uint16_t nInstructions = (uint16_t) StructAtOffset<HBUINT16> (glyph, 0);
glyph += 2 + nInstructions;
if (unlikely (glyph + 2 >= glyph_end)) return false;
unsigned int coordBytes = 0;
unsigned int coordsWithFlags = 0;
while (glyph < glyph_end)
{
uint8_t flag = (uint8_t) *glyph;
glyph++;
unsigned int repeat = 1;
if (flag & FLAG_REPEAT)
{
if (glyph >= glyph_end)
{
DEBUG_MSG(SUBSET, nullptr, "Bad flag");
return false;
}
repeat = ((uint8_t) *glyph) + 1;
glyph++;
}
unsigned int xBytes, yBytes;
xBytes = yBytes = 0;
if (flag & FLAG_X_SHORT) xBytes = 1;
else if ((flag & FLAG_X_SAME) == 0) xBytes = 2;
if (flag & FLAG_Y_SHORT) yBytes = 1;
else if ((flag & FLAG_Y_SAME) == 0) yBytes = 2;
coordBytes += (xBytes + yBytes) * repeat;
coordsWithFlags += repeat;
if (coordsWithFlags >= nCoordinates)
break;
}
if (coordsWithFlags != nCoordinates)
{
DEBUG_MSG(SUBSET, nullptr, "Expect %d coords to have flags, got flags for %d", nCoordinates, coordsWithFlags);
return false;
}
glyph += coordBytes;
if (glyph < glyph_end)
*end_offset -= glyph_end - glyph;
}
return true;
}
bool get_offsets (hb_codepoint_t glyph,
unsigned int *start_offset /* OUT */,
unsigned int *end_offset /* OUT */) const
{
if (unlikely (glyph >= num_glyphs))
return false;
if (short_offset)
{
const HBUINT16 *offsets = (const HBUINT16 *) loca_table->dataZ.arrayZ;
*start_offset = 2 * offsets[glyph];
*end_offset = 2 * offsets[glyph + 1];
}
else
{
const HBUINT32 *offsets = (const HBUINT32 *) loca_table->dataZ.arrayZ;
*start_offset = offsets[glyph];
*end_offset = offsets[glyph + 1];
}
if (*start_offset > *end_offset || *end_offset > glyf_table.get_length ())
return false;
return true;
}
bool get_instruction_offsets (unsigned int start_offset,
unsigned int end_offset,
unsigned int *instruction_start /* OUT */,
unsigned int *instruction_end /* OUT */) const
{
if (end_offset - start_offset < GlyphHeader::static_size)
{
*instruction_start = 0;
*instruction_end = 0;
return true; /* Empty glyph; no instructions. */
}
const GlyphHeader &glyph_header = StructAtOffset<GlyphHeader> (glyf_table, start_offset);
int16_t num_contours = (int16_t) glyph_header.numberOfContours;
if (num_contours < 0)
{
CompositeGlyphHeader::Iterator composite_it;
if (unlikely (!CompositeGlyphHeader::get_iterator (
(const char*) this->glyf_table + start_offset,
end_offset - start_offset, &composite_it))) return false;
const CompositeGlyphHeader *last;
do {
last = composite_it.current;
} while (composite_it.move_to_next ());
if ((uint16_t) last->flags & CompositeGlyphHeader::WE_HAVE_INSTRUCTIONS)
*instruction_start = ((char *) last - (char *) glyf_table->dataZ.arrayZ) + last->get_size ();
else
*instruction_start = end_offset;
*instruction_end = end_offset;
if (unlikely (*instruction_start > *instruction_end))
{
DEBUG_MSG(SUBSET, nullptr, "Invalid instruction offset, %d is outside [%d, %d]", *instruction_start, start_offset, end_offset);
return false;
}
}
else
{
unsigned int instruction_length_offset = start_offset + GlyphHeader::static_size + 2 * num_contours;
if (unlikely (instruction_length_offset + 2 > end_offset))
{
DEBUG_MSG(SUBSET, nullptr, "Glyph size is too short, missing field instructionLength.");
return false;
}
const HBUINT16 &instruction_length = StructAtOffset<HBUINT16> (glyf_table, instruction_length_offset);
unsigned int start = instruction_length_offset + 2;
unsigned int end = start + (uint16_t) instruction_length;
if (unlikely (end > end_offset)) // Out of bounds of the current glyph
{
DEBUG_MSG(SUBSET, nullptr, "The instructions array overruns the glyph's boundaries.");
return false;
}
*instruction_start = start;
*instruction_end = end;
}
return true;
}
unsigned int get_advance_var (hb_codepoint_t glyph,
const int *coords, unsigned int coord_count,
bool vertical) const
{
bool success = false;
hb_vector_t<contour_point_t> phantoms;
phantoms.resize (PHANTOM_COUNT);
if (likely (coord_count == gvar_accel.get_axis_count ()))
success = get_var_metrics (glyph, coords, coord_count, phantoms.as_array ());
if (unlikely (!success))
return vertical? vmtx_accel.get_advance (glyph): hmtx_accel.get_advance (glyph);
if (vertical)
return (unsigned int)roundf (phantoms[PHANTOM_TOP].y - phantoms[PHANTOM_BOTTOM].y);
else
return (unsigned int)roundf (phantoms[PHANTOM_RIGHT].x - phantoms[PHANTOM_LEFT].x);
}
int get_side_bearing_var (hb_codepoint_t glyph, const int *coords, unsigned int coord_count, bool vertical) const
{
hb_vector_t<contour_point_t> phantoms;
phantoms.resize (PHANTOM_COUNT);
if (unlikely (!get_var_metrics (glyph, coords, coord_count, phantoms)))
return vertical? vmtx_accel.get_side_bearing (glyph): hmtx_accel.get_side_bearing (glyph);
return (int)(vertical? -ceilf (phantoms[PHANTOM_TOP].y): floorf (phantoms[PHANTOM_LEFT].x));
}
bool get_extents (hb_font_t *font, hb_codepoint_t glyph, hb_glyph_extents_t *extents) const
{
unsigned int coord_count;
const int *coords = hb_font_get_var_coords_normalized (font, &coord_count);
if (coords && coord_count > 0 && coord_count == gvar_accel.get_axis_count ())
return get_extents_var (glyph, coords, coord_count, extents);
unsigned int start_offset, end_offset;
if (!get_offsets (glyph, &start_offset, &end_offset))
return false;
if (end_offset - start_offset < GlyphHeader::static_size)
return true; /* Empty glyph; zero extents. */
const GlyphHeader &glyph_header = StructAtOffset<GlyphHeader> (glyf_table, start_offset);
extents->x_bearing = MIN (glyph_header.xMin, glyph_header.xMax);
extents->y_bearing = MAX (glyph_header.yMin, glyph_header.yMax);
extents->width = MAX (glyph_header.xMin, glyph_header.xMax) - extents->x_bearing;
extents->height = MIN (glyph_header.yMin, glyph_header.yMax) - extents->y_bearing;
return true;
}
private:
bool short_offset;
unsigned int num_glyphs;
hb_blob_ptr_t<loca> loca_table;
hb_blob_ptr_t<glyf> glyf_table;
/* variable font support */
gvar::accelerator_t gvar_accel;
hmtx::accelerator_t hmtx_accel;
vmtx::accelerator_t vmtx_accel;
};
protected:
UnsizedArrayOf<HBUINT8> dataZ; /* Glyphs data. */
public:
DEFINE_SIZE_MIN (0); /* In reality, this is UNBOUNDED() type; but since we always
* check the size externally, allow Null() object of it by
* defining it MIN() instead. */
};
struct glyf_accelerator_t : glyf::accelerator_t {};
} /* namespace OT */
#endif /* HB_OT_GLYF_TABLE_HH */
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