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/*
* Copyright © 2011,2012 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, Roderick Sheeter
*/
#ifndef HB_OT_HMTX_TABLE_HH
#define HB_OT_HMTX_TABLE_HH
#include "hb-open-type.hh"
#include "hb-ot-hhea-table.hh"
#include "hb-ot-var-hvar-table.hh"
#include "hb-ot-metrics.hh"
/*
* hmtx -- Horizontal Metrics
* https://docs.microsoft.com/en-us/typography/opentype/spec/hmtx
* vmtx -- Vertical Metrics
* https://docs.microsoft.com/en-us/typography/opentype/spec/vmtx
*/
#define HB_OT_TAG_hmtx HB_TAG('h','m','t','x')
#define HB_OT_TAG_vmtx HB_TAG('v','m','t','x')
namespace OT {
struct LongMetric
{
UFWORD advance; /* Advance width/height. */
FWORD sb; /* Leading (left/top) side bearing. */
public:
DEFINE_SIZE_STATIC (4);
};
struct hmtxvmtx_accelerator_base_t
{
static int get_side_bearing_var_tt (hb_font_t *font HB_UNUSED,
hb_codepoint_t glyph HB_UNUSED,
bool is_vertical HB_UNUSED)
{ return 0; } /* Not implemented yet */
static unsigned int get_advance_var_tt (hb_font_t *font HB_UNUSED,
hb_codepoint_t glyph HB_UNUSED,
bool is_vertical HB_UNUSED)
{ return 0; } /* Not implemented yet */
};
template <typename T, typename H>
struct hmtxvmtx
{
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_update_header (hb_subset_plan_t *plan,
unsigned int num_hmetrics) const
{
hb_blob_t *src_blob = hb_sanitize_context_t ().reference_table<H> (plan->source, H::tableTag);
hb_blob_t *dest_blob = hb_blob_copy_writable_or_fail (src_blob);
hb_blob_destroy (src_blob);
if (unlikely (!dest_blob)) {
return false;
}
unsigned int length;
H *table = (H *) hb_blob_get_data (dest_blob, &length);
table->numberOfLongMetrics = num_hmetrics;
bool result = plan->add_table (H::tableTag, dest_blob);
hb_blob_destroy (dest_blob);
return result;
}
template<typename Iterator,
hb_requires (hb_is_iterator (Iterator))>
void serialize (hb_serialize_context_t *c,
Iterator it,
unsigned num_advances)
{
unsigned idx = 0;
+ it
| hb_apply ([c, &idx, num_advances] (const hb_item_type<Iterator>& _)
{
if (idx < num_advances)
{
LongMetric lm;
lm.advance = _.first;
lm.sb = _.second;
if (unlikely (!c->embed<LongMetric> (&lm))) return;
}
else
{
FWORD *sb = c->allocate_size<FWORD> (FWORD::static_size);
if (unlikely (!sb)) return;
*sb = _.second;
}
idx++;
})
;
}
bool subset (hb_subset_context_t *c) const
{
TRACE_SUBSET (this);
T *table_prime = c->serializer->start_embed <T> ();
if (unlikely (!table_prime)) return_trace (false);
accelerator_t _mtx;
_mtx.init (c->plan->source);
unsigned num_advances = _mtx.num_advances_for_subset (c->plan);
auto it =
+ hb_range (c->plan->num_output_glyphs ())
| hb_map ([c, &_mtx] (unsigned _)
{
hb_codepoint_t old_gid;
if (c->plan->old_gid_for_new_gid (_, &old_gid))
return hb_pair (_mtx.get_advance (old_gid), _mtx.get_side_bearing (old_gid));
else
return hb_pair (0u, 0);
})
;
table_prime->serialize (c->serializer, it, num_advances);
_mtx.fini ();
if (unlikely (c->serializer->ran_out_of_room || c->serializer->in_error ()))
return_trace (false);
// Amend header num hmetrics
if (unlikely (!subset_update_header (c->plan, num_advances)))
{
return_trace (false);
}
return_trace (true);
}
struct accelerator_t : hmtxvmtx_accelerator_base_t
{
friend struct hmtxvmtx;
void init (hb_face_t *face,
unsigned int default_advance_ = 0)
{
default_advance = default_advance_ ? default_advance_ : hb_face_get_upem (face);
num_advances = T::is_horizontal ? face->table.hhea->numberOfLongMetrics : face->table.vhea->numberOfLongMetrics;
table = hb_sanitize_context_t().reference_table<hmtxvmtx> (face, T::tableTag);
/* Cap num_metrics() and num_advances() based on table length. */
unsigned int len = table.get_length ();
if (unlikely (num_advances * 4 > len))
num_advances = len / 4;
num_metrics = num_advances + (len - 4 * num_advances) / 2;
/* We MUST set num_metrics to zero if num_advances is zero.
* Our get_advance() depends on that. */
if (unlikely (!num_advances))
{
num_metrics = num_advances = 0;
table.destroy ();
table = hb_blob_get_empty ();
}
var_table = hb_sanitize_context_t().reference_table<HVARVVAR> (face, T::variationsTag);
}
void fini ()
{
table.destroy ();
var_table.destroy ();
}
int get_side_bearing (hb_codepoint_t glyph) const
{
if (glyph < num_advances)
return table->longMetricZ[glyph].sb;
if (unlikely (glyph >= num_metrics))
return 0;
const FWORD *bearings = (const FWORD *) &table->longMetricZ[num_advances];
return bearings[glyph - num_advances];
}
int get_side_bearing (hb_font_t *font, hb_codepoint_t glyph) const
{
int side_bearing = get_side_bearing (glyph);
if (unlikely (glyph >= num_metrics) || !font->num_coords)
return side_bearing;
// if (var_table.get_blob () == &Null (hb_blob_t))
// return get_side_bearing_var_tt (font, glyph, T::tableTag == HB_OT_TAG_vmtx);
return side_bearing + var_table->get_side_bearing_var (glyph, font->coords, font->num_coords); // TODO Optimize?!
}
unsigned int get_advance (hb_codepoint_t glyph) const
{
if (unlikely (glyph >= num_metrics))
{
/* If num_metrics is zero, it means we don't have the metrics table
* for this direction: return default advance. Otherwise, it means that the
* glyph index is out of bound: return zero. */
if (num_metrics)
return 0;
else
return default_advance;
}
return table->longMetricZ[hb_min (glyph, (uint32_t) num_advances - 1)].advance;
}
unsigned int get_advance (hb_codepoint_t glyph,
hb_font_t *font) const
{
unsigned int advance = get_advance (glyph);
if (unlikely (glyph >= num_metrics) || !font->num_coords)
return advance;
// if (var_table.get_blob () == &Null (hb_blob_t))
// return get_advance_var_tt (font, glyph, T::tableTag == HB_OT_TAG_vmtx);
return advance + roundf (var_table->get_advance_var (glyph, font->coords, font->num_coords)); // TODO Optimize?!
}
unsigned int num_advances_for_subset (const hb_subset_plan_t *plan) const
{
unsigned int num_advances = plan->num_output_glyphs ();
unsigned int last_advance = _advance_for_new_gid (plan,
num_advances - 1);
while (num_advances > 1 &&
last_advance == _advance_for_new_gid (plan,
num_advances - 2))
{
num_advances--;
}
return num_advances;
}
private:
unsigned int _advance_for_new_gid (const hb_subset_plan_t *plan,
hb_codepoint_t new_gid) const
{
hb_codepoint_t old_gid;
if (!plan->old_gid_for_new_gid (new_gid, &old_gid))
return 0;
return get_advance (old_gid);
}
protected:
unsigned int num_metrics;
unsigned int num_advances;
unsigned int default_advance;
private:
hb_blob_ptr_t<hmtxvmtx> table;
hb_blob_ptr_t<HVARVVAR> var_table;
};
protected:
UnsizedArrayOf<LongMetric>longMetricZ;/* Paired advance width and leading
* bearing values for each glyph. The
* value numOfHMetrics comes from
* the 'hhea' table. If the font is
* monospaced, only one entry need
* be in the array, but that entry is
* required. The last entry applies to
* all subsequent glyphs. */
/*UnsizedArrayOf<FWORD> leadingBearingX;*//* Here the advance is assumed
* to be the same as the advance
* for the last entry above. The
* number of entries in this array is
* derived from numGlyphs (from 'maxp'
* table) minus numberOfLongMetrics.
* This generally is used with a run
* of monospaced glyphs (e.g., Kanji
* fonts or Courier fonts). Only one
* run is allowed and it must be at
* the end. This allows a monospaced
* font to vary the side bearing
* values for each glyph. */
public:
DEFINE_SIZE_ARRAY (0, longMetricZ);
};
struct hmtx : hmtxvmtx<hmtx, hhea> {
static constexpr hb_tag_t tableTag = HB_OT_TAG_hmtx;
static constexpr hb_tag_t variationsTag = HB_OT_TAG_HVAR;
static constexpr bool is_horizontal = true;
};
struct vmtx : hmtxvmtx<vmtx, vhea> {
static constexpr hb_tag_t tableTag = HB_OT_TAG_vmtx;
static constexpr hb_tag_t variationsTag = HB_OT_TAG_VVAR;
static constexpr bool is_horizontal = false;
};
struct hmtx_accelerator_t : hmtx::accelerator_t {};
struct vmtx_accelerator_t : vmtx::accelerator_t {};
} /* namespace OT */
#endif /* HB_OT_HMTX_TABLE_HH */