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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')
+
+
+HB_INTERNAL int
+_glyf_get_side_bearing_var (hb_font_t *font, hb_codepoint_t glyph, bool is_vertical);
+
+HB_INTERNAL unsigned
+_glyf_get_advance_var (hb_font_t *font, hb_codepoint_t glyph, bool is_vertical);
+
+
+namespace OT {
+
+
+struct LongMetric
+{
+ UFWORD advance; /* Advance width/height. */
+ FWORD sb; /* Leading (left/top) side bearing. */
+ public:
+ DEFINE_SIZE_STATIC (4);
+};
+
+
+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;
+ for (auto _ : it)
+ {
+ 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 (0u, 0);
+ return hb_pair (_mtx.get_advance (old_gid), _mtx.get_side_bearing (old_gid));
+ })
+ ;
+
+ 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
+ {
+ 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);
+
+#ifndef HB_NO_VAR
+ if (unlikely (glyph >= num_metrics) || !font->num_coords)
+ return side_bearing;
+
+ if (var_table.get_length ())
+ return side_bearing + var_table->get_side_bearing_var (glyph, font->coords, font->num_coords); // TODO Optimize?!
+
+ return _glyf_get_side_bearing_var (font, glyph, T::tableTag == HB_OT_TAG_vmtx);
+#else
+ return side_bearing;
+#endif
+ }
+
+ 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);
+
+#ifndef HB_NO_VAR
+ if (unlikely (glyph >= num_metrics) || !font->num_coords)
+ return advance;
+
+ if (var_table.get_length ())
+ return advance + roundf (var_table->get_advance_var (glyph, font)); // TODO Optimize?!
+
+ return _glyf_get_advance_var (font, glyph, T::tableTag == HB_OT_TAG_vmtx);
+#else
+ return advance;
+#endif
+ }
+
+ 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 */
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