From 3520f528aaba200ab2e3f1edfe746c7963a7ce54 Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Fri, 21 Apr 2023 15:46:36 -0600
Subject: [PATCH] [CompositeGlyph] Apply gvar deltas with component transform

This was being done wrong for one of the scaled_offsets() cases.
---
 src/OT/glyf/CompositeGlyph.hh | 37 +++++++++++++++++++++--------------
 src/OT/glyf/Glyph.hh          | 14 ++++++-------
 2 files changed, 29 insertions(+), 22 deletions(-)

diff --git a/src/OT/glyf/CompositeGlyph.hh b/src/OT/glyf/CompositeGlyph.hh
index f43dd2239..f599e1f7f 100644
--- a/src/OT/glyf/CompositeGlyph.hh
+++ b/src/OT/glyf/CompositeGlyph.hh
@@ -87,25 +87,32 @@ struct CompositeGlyphRecord
     }
   }
 
-  void transform_points (contour_point_vector_t &points) const
+  void transform_points (contour_point_vector_t &points,
+			 const float (&matrix)[4],
+			 const contour_point_t &trans) const
   {
-    float matrix[4];
-    contour_point_t trans;
-    if (get_transformation (matrix, trans))
+    if (scaled_offsets ())
     {
-      if (scaled_offsets ())
-      {
-	points.translate (trans);
-	points.transform (matrix);
-      }
-      else
-      {
-	points.transform (matrix);
-	points.translate (trans);
-      }
+      points.translate (trans);
+      points.transform (matrix);
+    }
+    else
+    {
+      points.transform (matrix);
+      points.translate (trans);
     }
   }
 
+  bool get_points (contour_point_vector_t &points) const
+  {
+    float matrix[4];
+    contour_point_t trans;
+    get_transformation (matrix, trans);
+    if (unlikely (!points.resize (points.length + 1))) return false;
+    points[points.length - 1] = trans;
+    return true;
+  }
+
   unsigned compile_with_deltas (const contour_point_t &p_delta,
                                 char *out) const
   {
@@ -171,6 +178,7 @@ struct CompositeGlyphRecord
   bool scaled_offsets () const
   { return (flags & (SCALED_COMPONENT_OFFSET | UNSCALED_COMPONENT_OFFSET)) == SCALED_COMPONENT_OFFSET; }
 
+  public:
   bool get_transformation (float (&matrix)[4], contour_point_t &trans) const
   {
     matrix[0] = matrix[3] = 1.f;
@@ -225,7 +233,6 @@ struct CompositeGlyphRecord
     return tx || ty;
   }
 
-  public:
   hb_codepoint_t get_gid () const
   {
 #ifndef HB_NO_BEYOND_64K
diff --git a/src/OT/glyf/Glyph.hh b/src/OT/glyf/Glyph.hh
index c9c0de45e..29b49389c 100644
--- a/src/OT/glyf/Glyph.hh
+++ b/src/OT/glyf/Glyph.hh
@@ -320,9 +320,8 @@ struct Glyph
       break;
     case COMPOSITE:
     {
-      /* pseudo component points for each component in composite glyph */
-      unsigned num_points = hb_len (CompositeGlyph (*header, bytes).iter ());
-      if (unlikely (!points.resize (num_points))) return false;
+      for (auto &item : get_composite_iterator ())
+        if (unlikely (!item.get_points (points))) return false;
       break;
     }
 #ifndef HB_NO_VAR_COMPOSITES
@@ -422,11 +421,12 @@ struct Glyph
 	  for (unsigned int i = 0; i < PHANTOM_COUNT; i++)
 	    phantoms[i] = comp_points[comp_points.length - PHANTOM_COUNT + i];
 
-	/* Apply component transformation & translation */
-	item.transform_points (comp_points);
+	float matrix[4];
+	contour_point_t default_trans;
+	item.get_transformation (matrix, default_trans);
 
-	/* Apply translation from gvar */
-	comp_points.translate (points[comp_index]);
+	/* Apply component transformation & translation (with deltas applied) */
+	item.transform_points (comp_points, matrix, points[comp_index]);
 
 	if (item.is_anchored ())
 	{