[ot-glyph] move glyph decompose logic of glyf to itself

One less vector allocation yet isn't zero alloc yet
which needs more work.

src/hb-ot-glyf-table.hh

@@ -1043,10 +1043,10 @@ struct glyf
     }
 
     bool
-    get_path (hb_font_t *font, hb_codepoint_t gid, hb_vector_t<hb_position_t> *coords, hb_vector_t<uint8_t> *commands) const
+    get_path (hb_font_t *font, hb_codepoint_t gid,
+	      hb_ot_glyph_decompose_funcs_t *funcs, void *user_data) const
     {
-#define PUSH_POINT(x, y) HB_STMT_START { coords->push (font->em_scalef_x (x)); coords->push (font->em_scalef_y (y)); } HB_STMT_END
-#define PUSH_POINT_CMD(c, x, y) HB_STMT_START { commands->push (c); PUSH_POINT(x, y); } HB_STMT_END
+      /* TODO: Make it work alloc free and without all_points vector */
       contour_point_vector_t all_points;
       if (unlikely (!get_points (font, gid, all_points))) return false;
       hb_array_t<contour_point_t> points = all_points.sub_array (0, all_points.length - 4);
@@ -1065,14 +1065,15 @@ struct glyf
 	contour_point_t *next = &points[contour_start];
 
 	if (curr->flag & Glyph::FLAG_ON_CURVE)
-	  PUSH_POINT_CMD ('M', curr->x, curr->y);
+	  funcs->move_to (font->em_scalef_x (curr->x), font->em_scalef_y (curr->y), user_data);
 	else
 	{
 	  if (next->flag & Glyph::FLAG_ON_CURVE)
-	    PUSH_POINT_CMD ('M', next->x, next->y);
+            funcs->move_to (font->em_scalef_x (next->x), font->em_scalef_y (next->y), user_data);
 	  else
-	  /* If both first and last points are off-curve, start at their middle. */
-	    PUSH_POINT_CMD ('M', (curr->x + next->x) / 2.f, (curr->y + next->y) / 2.f);
+	    /* If both first and last points are off-curve, start at their middle. */
+            funcs->move_to (font->em_scalef_x ((curr->x + next->x) / 2.f),
+			    font->em_scalef_y ((curr->y + next->y) / 2.f), user_data);
 	}
 
 	for (unsigned i = 0; i < contour_length; ++i)
@@ -1081,21 +1082,19 @@ struct glyf
 	  next = &points[contour_start + ((i + 1) % contour_length)];
 
 	  if (curr->flag & Glyph::FLAG_ON_CURVE)
-	    PUSH_POINT_CMD ('L', curr->x, curr->y); /* straight line */
+	    funcs->line_to (font->em_scalef_x (curr->x), font->em_scalef_y (curr->y), user_data);
 	  else
 	  {
-	    PUSH_POINT_CMD ('Q', curr->x, curr->y);
-	    if (next->flag & Glyph::FLAG_ON_CURVE)
-	      PUSH_POINT (next->x, next->y);
-	    else
-	      PUSH_POINT ((curr->x + next->x) / 2.f, (curr->y + next->y) / 2.f);
+	    float to_x, to_y;
+	    if (next->flag & Glyph::FLAG_ON_CURVE) { to_x = next->x; to_y = next->y; }
+	    else { to_x = (curr->x + next->x) / 2.f; to_y = (curr->y + next->y) / 2.f; }
+	    funcs->conic_to (font->em_scalef_x (curr->x), font->em_scalef_y (curr->y),
+			     font->em_scalef_x (to_x), font->em_scalef_y (to_y), user_data);
 	  }
 	}
-	commands->push ('Z');
+	/* funcs->end_path (); */
 	contour_start += contour_length;
       }
-#undef PUSH_POINT_CMD
-#undef PUSH_POINT
       return true;
     }
 

src/hb-ot-glyph.cc

@@ -38,16 +38,15 @@ hb_ot_glyph_decompose (hb_font_t *font, hb_codepoint_t glyph,
 {
   if (unlikely (!funcs || glyph >= font->face->get_num_glyphs ())) return false;
 
+  if (font->face->table.glyf->get_path (font, glyph, funcs, user_data)) return true;
+
+#ifndef HB_NO_OT_FONT_CFF
   hb_vector_t<hb_position_t> coords;
   hb_vector_t<uint8_t> commands;
 
   bool ret = false;
-
-  if (!ret) ret = font->face->table.glyf->get_path (font, glyph, &coords, &commands);
-#ifndef HB_NO_OT_FONT_CFF
   if (!ret) ret = font->face->table.cff1->get_path (font, glyph, &coords, &commands);
   if (!ret) ret = font->face->table.cff2->get_path (font, glyph, &coords, &commands);
-#endif
 
   if (unlikely (!ret || coords.length % 2 != 0)) return false;
 
@@ -68,12 +67,6 @@ hb_ot_glyph_decompose (hb_font_t *font, hb_codepoint_t glyph,
       funcs->line_to (coords[coords_idx + 0], coords[coords_idx + 1], user_data);
       coords_idx += 2;
       break;
-    case 'Q':
-      if (unlikely (coords.length < coords_idx + 4)) return false;
-      funcs->conic_to (coords[coords_idx + 0], coords[coords_idx + 1],
-		       coords[coords_idx + 2], coords[coords_idx + 3], user_data);
-      coords_idx += 4;
-      break;
     case 'C':
       if (unlikely (coords.length >= coords_idx + 6)) return false;
       funcs->cubic_to (coords[coords_idx + 0], coords[coords_idx + 1],
@@ -84,6 +77,9 @@ hb_ot_glyph_decompose (hb_font_t *font, hb_codepoint_t glyph,
     }
 
   return true;
+#endif
+
+  return false;
 }
 
 #endif

src/test-ot-glyph.cc

@@ -107,7 +107,12 @@ main (int argc, char **argv)
       hb_font_extents_t font_extents;
       hb_font_get_extents_for_direction (font, HB_DIRECTION_LTR, &font_extents);
       hb_glyph_extents_t extents = {0};
-      hb_font_get_glyph_extents (font, gid, &extents);
+      if (!hb_font_get_glyph_extents (font, gid, &extents))
+      {
+        printf ("Skip gid: %d\n", gid);
+	continue;
+      }
+
       char name[100];
       sprintf (name, "%d.svg", gid);
       FILE *f = fopen (name, "wb");