[ot-glyph] rewrite the API

src/hb-ot-glyph.cc

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2019  Ebrahim Byagowi
+ * Copyright © 2019-2020  Ebrahim Byagowi
  *
  *  This is part of HarfBuzz, a text shaping library.
  *
@@ -31,133 +31,15 @@
 #include "hb-ot-cff1-table.hh"
 #include "hb-ot-cff2-table.hh"
 
-struct hb_ot_glyph_path_t
+hb_bool_t
+hb_ot_glyph_decompose (hb_font_t *font, hb_codepoint_t glyph,
+		       hb_ot_glyph_decompose_funcs_t *funcs,
+		       void *user_data)
 {
-  hb_object_header_t header;
+  if (unlikely (!funcs || glyph >= font->face->get_num_glyphs ())) return false;
 
-  const hb_position_t *coords;
+  hb_vector_t<hb_position_t> coords;
-  unsigned int coords_count;
+  hb_vector_t<uint8_t> commands;
-
-  const uint8_t *commands;
-  unsigned int commands_count;
-
-  void *user_data;
-  hb_destroy_func_t destroy;
-};
-
-hb_ot_glyph_path_t *
-hb_ot_glyph_path_empty ()
-{
-  return const_cast<hb_ot_glyph_path_t *> (&Null (hb_ot_glyph_path_t));
-}
-
-hb_ot_glyph_path_t *
-hb_ot_glyph_path_create (hb_position_t     *coords,
-			 unsigned int       coords_count,
-			 uint8_t           *commands,
-			 unsigned int       commands_count,
-			 void              *user_data,
-			 hb_destroy_func_t  destroy)
-{
-  hb_ot_glyph_path_t *path;
-
-  if (!coords_count || !commands_count ||
-      !(path = hb_object_create<hb_ot_glyph_path_t> ()))
-  {
-    if (destroy)
-      destroy (user_data);
-    return hb_ot_glyph_path_empty ();
-  }
-
-  path->coords = coords;
-  path->coords_count =  coords_count;
-  path->commands = commands;
-  path->commands_count = commands_count;
-  path->user_data = user_data;
-  path->destroy = destroy;
-
-  return path;
-}
-
-const hb_position_t *
-hb_ot_glyph_path_get_coords (hb_ot_glyph_path_t *path, unsigned int *count)
-{
-  if (count) *count = path->coords_count;
-  return path->coords;
-}
-
-const uint8_t *
-hb_ot_glyph_path_get_commands (hb_ot_glyph_path_t *path, unsigned int *count)
-{
-  if (count) *count = path->commands_count;
-  return path->commands;
-}
-
-hb_ot_glyph_path_t *
-hb_ot_glyph_path_reference (hb_ot_glyph_path_t *path)
-{
-  return hb_object_reference (path);
-}
-
-void
-hb_ot_glyph_path_destroy (hb_ot_glyph_path_t *path)
-{
-  if (!hb_object_destroy (path)) return;
-
-  if (path->destroy) path->destroy (path->user_data);
-
-  free (path);
-}
-
-struct _hb_ot_glyph_path_vectors
-{
-  hb_vector_t<hb_position_t> *coords;
-  hb_vector_t<uint8_t> *commands;
-
-  bool init ()
-  {
-    coords = (hb_vector_t<hb_position_t> *) malloc (sizeof (hb_vector_t<hb_position_t>));
-    commands = (hb_vector_t<uint8_t> *) malloc (sizeof (hb_vector_t<uint8_t>));
-    if (unlikely (!coords || !commands))
-    {
-      free (coords);
-      free (commands);
-      return false;
-    }
-    coords->init ();
-    commands->init ();
-    return true;
-  }
-
-  void fini ()
-  {
-    coords->fini ();
-    commands->fini ();
-    free (coords);
-    free (commands);
-  }
-};
-
-static void
-_hb_ot_glyph_path_free_vectors (void *user_data)
-{
-  ((_hb_ot_glyph_path_vectors *) user_data)->fini ();
-  free (user_data);
-}
-
-hb_ot_glyph_path_t *
-hb_ot_glyph_path_create_from_font (hb_font_t *font, hb_codepoint_t glyph)
-{
-  _hb_ot_glyph_path_vectors *user_data = (_hb_ot_glyph_path_vectors *)
-					 malloc (sizeof (_hb_ot_glyph_path_vectors));
-  if (unlikely (!user_data || !user_data->init () || glyph >= font->face->get_num_glyphs ()))
-  {
-    free (user_data);
-    return hb_ot_glyph_path_empty ();
-  }
-
-  hb_vector_t<hb_position_t> &coords = *user_data->coords;
-  hb_vector_t<uint8_t> &commands = *user_data->commands;
 
   bool ret = false;
 
@@ -167,17 +49,41 @@ hb_ot_glyph_path_create_from_font (hb_font_t *font, hb_codepoint_t glyph)
   if (!ret) ret = font->face->table.cff2->get_path (font, glyph, &coords, &commands);
 #endif
 
-  assert (coords.length % 2 == 0); /* coords pairs, should be an even number */
+  if (unlikely (!ret || coords.length % 2 != 0)) return false;
 
-  if (unlikely (!ret))
+  /* FIXME: We should do all these memory O(1) without hb_vector_t
-  {
+	    by moving the logic to the tables */
-    user_data->fini ();
+  unsigned int coords_idx = 0;
-    free (user_data);
+  for (unsigned int i = 0; i < commands.length; ++i)
-    return hb_ot_glyph_path_empty ();
+    switch (commands[i])
-  }
+    {
+    case 'Z': break;
+    case 'M':
+      if (unlikely (coords.length < coords_idx + 2)) return false;
+      funcs->move_to (coords[coords_idx + 0], coords[coords_idx + 1], user_data);
+      coords_idx += 2;
+      break;
+    case 'L':
+      if (unlikely (coords.length < coords_idx + 2)) return false;
+      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],
+		       coords[coords_idx + 2], coords[coords_idx + 3],
+		       coords[coords_idx + 4], coords[coords_idx + 5], user_data);
+      coords_idx += 6;
+      break;
+    }
 
-  return hb_ot_glyph_path_create (coords.arrayZ, coords.length, commands.arrayZ, commands.length,
+  return true;
-				  user_data, (hb_destroy_func_t) _hb_ot_glyph_path_free_vectors);
 }
 
 #endif

src/hb-ot-glyph.h

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2019  Ebrahim Byagowi
+ * Copyright © 2019-2020  Ebrahim Byagowi
  *
  *  This is part of HarfBuzz, a text shaping library.
  *
@@ -33,34 +33,39 @@
 
 HB_BEGIN_DECLS
 
-typedef struct hb_ot_glyph_path_t hb_ot_glyph_path_t;
+typedef void (*hb_ot_glyph_decompose_move_to_func_t) (hb_position_t to_x, hb_position_t to_y, void *user_data);
+typedef void (*hb_ot_glyph_decompose_line_to_func_t) (hb_position_t to_x, hb_position_t to_y, void *user_data);
+typedef void (*hb_ot_glyph_decompose_conic_to_func_t) (hb_position_t control_x, hb_position_t control_y,
+						       hb_position_t to_x, hb_position_t to_y,
+						       void *user_data);
+typedef void (*hb_ot_glyph_decompose_cubic_to_func_t) (hb_position_t control1_x, hb_position_t control1_y,
+						       hb_position_t control2_x, hb_position_t control2_y,
+						       hb_position_t to_x, hb_position_t to_y,
+						       void *user_data);
 
-HB_EXTERN hb_ot_glyph_path_t *
+/**
-hb_ot_glyph_path_create (hb_position_t     *coords,
+ * hb_ot_glyph_decompose_funcs_t:
-			 unsigned int       coords_count,
+ *
-			 uint8_t           *commands,
+ * Glyph decompose callbacks.
-			 unsigned int       commands_count,
+ *
-			 void              *user_data,
+ * Since: REPLACEME
-			 hb_destroy_func_t  destroy);
+ **/
-
+typedef struct hb_ot_glyph_decompose_funcs_t
-HB_EXTERN hb_ot_glyph_path_t *
+{
-hb_ot_glyph_path_create_from_font (hb_font_t *font, hb_codepoint_t glyph);
+  hb_ot_glyph_decompose_move_to_func_t move_to;
-
+  hb_ot_glyph_decompose_line_to_func_t line_to;
-HB_EXTERN void
+  hb_ot_glyph_decompose_conic_to_func_t conic_to;
-hb_ot_glyph_path_destroy (hb_ot_glyph_path_t *path);
+  hb_ot_glyph_decompose_cubic_to_func_t cubic_to;
-
+  /*< private >*/
-HB_EXTERN hb_ot_glyph_path_t *
+  void *reserved4;
-hb_ot_glyph_path_empty (void);
+  void *reserved3;
-
+  void *reserved2;
-HB_EXTERN const uint8_t *
+  void *reserved1;
-hb_ot_glyph_path_get_commands (hb_ot_glyph_path_t *path, unsigned int *count);
+} hb_ot_glyph_decompose_funcs_t;
-
-HB_EXTERN const hb_position_t *
-hb_ot_glyph_path_get_coords (hb_ot_glyph_path_t *path, unsigned int *count);
-
-HB_EXTERN hb_ot_glyph_path_t *
-hb_ot_glyph_path_reference (hb_ot_glyph_path_t *path);
 
+hb_bool_t
+hb_ot_glyph_decompose (hb_font_t *font, hb_codepoint_t glyph,
+		       hb_ot_glyph_decompose_funcs_t *funcs, void *user_data);
 
 HB_END_DECLS
 

src/test-ot-glyph.cc

@@ -32,6 +32,48 @@
 #include <stdio.h>
 #include <assert.h>
 
+struct user_data_t
+{
+  FILE *f;
+  hb_position_t ascender;
+};
+
+static void
+move_to (hb_position_t to_x, hb_position_t to_y, void *user_data)
+{
+  user_data_t u = *((user_data_t *) user_data);
+  fprintf (u.f, "M%d,%d", to_x, u.ascender - to_y);
+}
+
+static void
+line_to (hb_position_t to_x, hb_position_t to_y, void *user_data)
+{
+  user_data_t u = *((user_data_t *) user_data);
+  fprintf (u.f, "L%d,%d", to_x, u.ascender - to_y);
+}
+
+static void
+conic_to (hb_position_t control_x, hb_position_t control_y,
+	  hb_position_t to_x, hb_position_t to_y,
+	  void *user_data)
+{
+  user_data_t u = *((user_data_t *) user_data);
+  fprintf (u.f, "Q%d,%d %d,%d", control_x, u.ascender - control_y,
+				to_x, u.ascender - to_y);
+}
+
+static void
+cubic_to (hb_position_t control1_x, hb_position_t control1_y,
+	  hb_position_t control2_x, hb_position_t control2_y,
+	  hb_position_t to_x, hb_position_t to_y,
+	  void *user_data)
+{
+  user_data_t u = *((user_data_t *) user_data);
+  fprintf (u.f, "C%d,%d %d,%d %d,%d", control1_x, u.ascender - control1_y,
+				      control2_x, u.ascender - control2_y,
+				      to_x, u.ascender - to_y);
+}
+
 int
 main (int argc, char **argv)
 {
@@ -49,6 +91,12 @@ main (int argc, char **argv)
     exit (1);
   }
 
+  hb_ot_glyph_decompose_funcs_t funcs;
+  funcs.move_to = (hb_ot_glyph_decompose_move_to_func_t) move_to;
+  funcs.line_to = (hb_ot_glyph_decompose_line_to_func_t) line_to;
+  funcs.conic_to = (hb_ot_glyph_decompose_conic_to_func_t) conic_to;
+  funcs.cubic_to = (hb_ot_glyph_decompose_cubic_to_func_t) cubic_to;
+
   for (unsigned int face_index = 0; face_index < hb_face_count (blob); face_index++)
   {
     hb_face_t *face = hb_face_create (blob, face_index);
@@ -67,38 +115,13 @@ main (int argc, char **argv)
 		  " viewBox=\"%d %d %d %d\"><path d=\"",
 		  extents.x_bearing, 0,
 		  extents.x_bearing + extents.width, font_extents.ascender - font_extents.descender); //-extents.height);
-      hb_ot_glyph_path_t *path = hb_ot_glyph_path_create_from_font (font, gid);
+      user_data_t user_data;
-      unsigned int commands_count;
+      user_data.ascender = font_extents.ascender;
-      const uint8_t *commands = hb_ot_glyph_path_get_commands (path, &commands_count);
+      user_data.f = f;
-      unsigned int coords_count;
+      if (!hb_ot_glyph_decompose (font, gid, &funcs, &user_data))
-      const hb_position_t *coords = hb_ot_glyph_path_get_coords (path, &coords_count);
+        printf ("Failed to decompose gid: %d\n", gid);
-      unsigned j = 0;
-      for (unsigned i = 0; i < commands_count && j < coords_count; ++i)
-      {
-	fprintf (f, "%c", commands[i]);
-	if (commands[i] == 'Z') continue;
-	assert (coords_count >= j + 2);
-	fprintf (f, "%d,%d", coords[j], font_extents.ascender - coords[j + 1]); //extents.y_bearing - points[i].y);
-	j += 2;
-	if (commands[i] == 'Q')
-	{
-	  assert (coords_count >= j + 2);
-	  fprintf (f, " %d,%d", coords[j], font_extents.ascender - coords[j + 1]); //extents.y_bearing - points[i].y);
-	  j += 2;
-	}
-	if (commands[i] == 'C')
-	{
-	  assert (coords_count >= j + 4);
-	  fprintf (f, " %d,%d", coords[j], font_extents.ascender - coords[j + 1]); //extents.y_bearing - points[i].y);
-	  j += 2;
-	  fprintf (f, " %d,%d", coords[j], font_extents.ascender - coords[j + 1]); //extents.y_bearing - points[i].y);
-	  j += 2;
-	}
-      }
-      assert (coords_count == j);
       fprintf (f, "\"/></svg>");
       fclose (f);
-      hb_ot_glyph_path_destroy (path);
     }
     hb_font_destroy (font);
     hb_face_destroy (face);