[HVAC] Start adding table

src/OT/glyf/Glyph.hh

@@ -7,6 +7,7 @@
 #include "GlyphHeader.hh"
 #include "SimpleGlyph.hh"
 #include "CompositeGlyph.hh"
+#include "../../hb-ot-var-hvac-table.hh"
 
 
 namespace OT {
@@ -388,10 +389,18 @@ struct Glyph
 
 #ifndef HB_NO_VAR
     if (coords)
-      glyf_accelerator.gvar->apply_deltas_to_points (gid,
-						     coords,
-						     points.as_array ().sub_array (old_length),
-						     phantom_only && type == SIMPLE);
+    {
+      auto &HVAC = *font->face->table.HVAC;
+      if (HVAC.has_data ())
+	HVAC.apply_deltas_to_points (gid,
+				     coords,
+				     points.as_array ().sub_array (old_length));
+      else
+	glyf_accelerator.gvar->apply_deltas_to_points (gid,
+						      coords,
+						      points.as_array ().sub_array (old_length),
+						      phantom_only && type == SIMPLE);
+    }
 #endif
 
     // mainly used by CompositeGlyph calculating new X/Y offset value so no need to extend it

src/hb-ot-face-table-list.hh

@@ -95,6 +95,7 @@ HB_OT_CORE_TABLE (OT, fvar)
 HB_OT_CORE_TABLE (OT, avar)
 HB_OT_CORE_TABLE (OT, cvar)
 HB_OT_ACCELERATOR (OT, gvar)
+HB_OT_CORE_TABLE (OT, HVAC)
 HB_OT_CORE_TABLE (OT, MVAR)
 #ifndef HB_NO_VAR_COMPOSITES
 HB_OT_CORE_TABLE (OT, VARC)

src/hb-ot-var-hvac-table.hh

@@ -0,0 +1,181 @@
+/*
+ * Copyright © 2024  Google LLC.
+ *
+ *  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.
+ *
+ * Author(s): Behdad Esfahbod
+ */
+
+#ifndef HB_OT_VAR_HVAC_TABLE_HH
+#define HB_OT_VAR_HVAC_TABLE_HH
+
+#include "hb-open-type.hh"
+#include "hb-ot-var-common.hh"
+
+/*
+ * HVAC -- gvar replacement table with floats
+ */
+#define HB_OT_TAG_HVAC HB_TAG('H','V','A','C')
+
+namespace OT {
+
+struct GlyphVariationDelta
+{
+  unsigned get_size (unsigned deltasCount) const
+  {
+    return regionIndex.static_size + deltasCount * sizeof (deltasZ) * 2;
+  }
+
+  void apply_deltas_to_points (unsigned deltasCount,
+			       hb_array_t<const int> coords,
+			       hb_array_t<contour_point_t> points,
+			       const SparseVarRegionList &varRegionList) const
+  {
+    float scalar = varRegionList.evaluate (regionIndex, coords, coords.length);
+    if (scalar == 0)
+      return;
+
+    const float *x = deltasZ;
+    const float *y = deltasZ + deltasCount;
+    if (scalar == 1)
+      for (unsigned i = 0; i < deltasCount; i++)
+      {
+        auto &point = points[i];
+	point.x += x[i];
+	point.y += y[i];
+      }
+    else
+      for (unsigned i = 0; i < deltasCount; i++)
+      {
+	auto &point = points[i];
+	point.x += x[i] * scalar;
+	point.y += y[i] * scalar;
+      }
+  }
+
+  bool sanitize (hb_sanitize_context_t *c, unsigned deltasCount) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this) &&
+		  hb_barrier () &&
+		  c->check_range (this, get_size (deltasCount)));
+  }
+
+  protected:
+  HBUINT32 regionIndex; /* Index of the sparse variation region that applies to this delta set. */
+  float deltasZ[HB_VAR_ARRAY]; /* Array of variation data; Xs first then Ys. */
+
+  public:
+  DEFINE_SIZE_MIN (4);
+};
+
+struct GlyphVariationDeltas
+{
+  void apply_deltas_to_points (hb_array_t<const int> coords,
+			       hb_array_t<contour_point_t> points,
+			       const SparseVarRegionList &varRegionList) const
+  {
+    const HBUINT8 *p = deltaSets;
+    for (unsigned i = 0; i < deltasCount; i++)
+    {
+      const GlyphVariationDelta &delta = *(const GlyphVariationDelta *) p;
+
+      delta.apply_deltas_to_points (deltasCount, coords, points, varRegionList);
+
+      p += delta.get_size (deltasCount);
+    }
+  }
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    if (unlikely (!c->check_struct (this)))
+      return_trace (false);
+
+    const HBUINT8 *p = deltaSets;
+    for (unsigned i = 0; i < deltasCount; i++)
+    {
+      const GlyphVariationDelta &delta = *(const GlyphVariationDelta *) p;
+
+      if (unlikely (!delta.sanitize (c, deltasCount)))
+        return_trace (false);
+
+      p += delta.get_size (deltasCount);
+    }
+
+    return_trace (true);
+  }
+
+  protected:
+  HBUINT16 deltasCount;	/* Number of points in the variation data */
+  HBUINT16 deltaSetCount; /* Number of variation delta sets */
+  HBUINT8 deltaSets[HB_VAR_ARRAY]; /* Data */
+
+  public:
+  DEFINE_SIZE_ARRAY (4, deltaSets);
+};
+
+struct HVAC
+{
+  static constexpr hb_tag_t tableTag = HB_OT_TAG_HVAC;
+
+  bool has_data () const { return version.major != 0; }
+
+  void apply_deltas_to_points (hb_codepoint_t gid,
+			       hb_array_t<const int> coords,
+			       hb_array_t<contour_point_t> points) const
+  {
+    unsigned idx = (this+coverage).get_coverage (gid);
+    if (idx == NOT_COVERED)
+      return;
+
+    const auto &deltaSet = (this+glyphDeltaSets[idx]);
+    deltaSet.apply_deltas_to_points (coords, points, (this+varRegionList));
+  }
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this) &&
+		  hb_barrier () &&
+		  (version.major == 1) &&
+		  varRegionList.sanitize (c, this) &&
+		  coverage.sanitize (c, this) &&
+		  glyphDeltaSets.sanitize (c, this));
+  }
+
+  protected:
+  FixedVersion<>version;	/* Version number of the glyph variations table
+				 * Set to 0x00010000u. */
+  Offset32To<SparseVarRegionList> varRegionList;
+				/* Offset from the start of this table to the array of
+				 * sparse variation region lists. */
+
+  Offset32To<Coverage> coverage; /* Offset from the start of this table to the coverage table. */
+  Array32Of<Offset32To<GlyphVariationDeltas>>
+		       glyphDeltaSets; /* Array of glyph variation data tables. */
+  public:
+  DEFINE_SIZE_ARRAY (16, glyphDeltaSets);
+};
+
+} /* namespace OT */
+
+#endif /* HB_OT_VAR_HVAC_TABLE_HH */