[libchamplain] Improve background texture code

[Jiří Techet <jiritechet src gnome org>]

commit fd8a2a359523b89b15cbf28edd3a64157e81bf3a
Author: Jiří Techet <techet gmail com>
Date:   Mon Apr 8 17:59:50 2013 +0200

    Improve background texture code
    
    Add custom background tile texture support, improve performance by making
    texture clone instead of redrawing it every time, make background tile
    size independent of the map tile size, display background
    texture also at zoom level 0, show background texture all the time during
    zoom animation, fix some minor bugs and make minor cleanups.

 champlain/champlain-view.c |  231 ++++++++++++++++++++++++++------------------
 champlain/champlain-view.h |    4 +
 demos/launcher-gtk.c       |   51 ++++++++++
 3 files changed, 194 insertions(+), 92 deletions(-)
---
diff --git a/champlain/champlain-view.c b/champlain/champlain-view.c
index 620ada1..95e2e2c 100644
--- a/champlain/champlain-view.c
+++ b/champlain/champlain-view.c
@@ -102,6 +102,7 @@ enum
   PROP_ZOOM_ON_DOUBLE_CLICK,
   PROP_ANIMATE_ZOOM,
   PROP_STATE,
+  PROP_BACKGROUND_TILE,
 };
 
 #define PADDING 10
@@ -116,8 +117,6 @@ static guint signals[LAST_SIGNAL] = { 0, };
    level < champlain_map_source_get_min_zoom_level (priv->map_source) || \
            level > champlain_map_source_get_max_zoom_level (priv->map_source))
 
-#define CHAMPLAIN_BACKGROUND_TILE_SQUARE_SIZE 8
-
 /* Between state values for go_to */
 typedef struct
 {
@@ -148,6 +147,8 @@ struct _ChamplainViewPrivate
   ClutterActor *zoom_layer; 
   ClutterActor *license_actor; /* Contains the license info */
 
+  ClutterTexture *background_tile_actor; 
+
   ClutterLayoutManager *layout_manager;
 
   ChamplainMapSource *map_source; /* Current map tile source */
@@ -239,12 +240,6 @@ static void champlain_view_go_to_with_duration (ChamplainView *view,
     gdouble longitude,
     guint duration);
 static gboolean fill_tile_cb (FillTileCallbackData *data);
-static void view_position_background_tile (ChamplainView *view,
-    ClutterActor *actor,
-    gint x,
-    gint y,
-    gint size);
-static ClutterActor *fill_background_tile (gint size);
 
 
 /* Updates the internals after the viewport changed */
@@ -459,6 +454,10 @@ champlain_view_get_property (GObject *object,
       g_value_set_enum (value, priv->state);
       break;
 
+    case PROP_BACKGROUND_TILE:
+      g_value_set_object (value, priv->background_tile_actor);
+      break;
+
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
     }
@@ -524,6 +523,10 @@ champlain_view_set_property (GObject *object,
       champlain_view_set_animate_zoom (view, g_value_get_boolean (value));
       break;
       
+    case PROP_BACKGROUND_TILE:
+      champlain_view_set_background_tile (view, g_value_get_object (value));
+      break;
+
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
     }
@@ -570,6 +573,12 @@ champlain_view_dispose (GObject *object)
       clutter_actor_unparent (CLUTTER_ACTOR (priv->view_box));
       priv->view_box = NULL;
     }
+    
+  if (priv->background_tile_actor)
+    {
+      clutter_actor_destroy (CLUTTER_ACTOR (priv->background_tile_actor));
+      priv->background_tile_actor = NULL;
+    }
 
   priv->map_layer = NULL;
   priv->license_actor = NULL;
@@ -987,6 +996,21 @@ champlain_view_class_init (ChamplainViewClass *champlainViewClass)
           G_PARAM_READABLE));
 
   /**
+   * ChamplainView:background-tile:
+   *
+   * The pattern displayed in the background of the map.
+   *
+   * Since: 0.12.4
+   */
+  g_object_class_install_property (object_class,
+      PROP_BACKGROUND_TILE,
+      g_param_spec_object ("background-tile",
+          "Background tile",
+          "The tile's background pattern",
+          CLUTTER_TYPE_ACTOR,
+          G_PARAM_READWRITE));
+
+  /**
    * ChamplainView::animation-completed:
    *
    * The #ChamplainView::animation-completed signal is emitted when any animation in the view
@@ -1068,6 +1092,7 @@ champlain_view_init (ChamplainView *view)
   priv->tiles_loading = 0;
   priv->update_viewport_timer = g_timer_new ();
   priv->zoom_animation = NULL;
+  priv->background_tile_actor = NULL;
 
   /* Setup map layer */
   priv->map_layer = champlain_group_new ();
@@ -1903,53 +1928,71 @@ champlain_view_get_viewport_origin (ChamplainView *view,
     *y = priv->viewport_y;
 }
 
-static ClutterActor *
-fill_background_tile (gint size)
+
+static void
+fill_background_tiles (ChamplainView *view)
 {
   DEBUG_LOG ()
 
-  ClutterActor *actor = NULL;
-  cairo_t *cr;
-  cairo_pattern_t *pat;
-  gint no_of_squares = size / CHAMPLAIN_BACKGROUND_TILE_SQUARE_SIZE;
-  gint row, column;
+  ChamplainViewPrivate *priv = view->priv;
+  GList *children, *child;
+  gint children_count;
+  gint tiles_count, x_count, y_count, x_first, y_first;
+  gdouble x_coord, y_coord;
+  gint i, x, y, size;
 
-  actor = clutter_cairo_texture_new (size, size);
+  size = clutter_actor_get_width (CLUTTER_ACTOR (priv->background_tile_actor));
+  
+  x_coord = priv->viewport_x + priv->anchor_x;
+  y_coord = priv->viewport_y + priv->anchor_y;
 
-  /* Create the background tile */
-  cr = clutter_cairo_texture_create (CLUTTER_CAIRO_TEXTURE (actor));
-  pat = cairo_pattern_create_linear (size / 2.0, 0.0, size, size / 2.0);
-  cairo_pattern_add_color_stop_rgb (pat, 0, 0.662, 0.662, 0.662);
-  cairo_set_source (cr, pat);
-  cairo_rectangle (cr, 0, 0, size, size);
-  cairo_fill (cr);
-  cairo_pattern_destroy (pat);
+  x_count = ceil ((float) priv->viewport_width / size) + 2;
+  y_count = ceil ((float) priv->viewport_height / size) + 2;
+  tiles_count = x_count * y_count;
 
-  /* Filling the tile */
-  cairo_set_source_rgb (cr, 0.411, 0.411, 0.411);
-  cairo_set_line_cap (cr, CAIRO_LINE_CAP_ROUND);
+  x_first = x_coord / size - 1;
+  y_first = y_coord / size - 1;
 
-  for (row = 0; row < no_of_squares; ++row)
+  children = clutter_container_get_children (CLUTTER_CONTAINER (priv->background_layer));
+  children_count = g_list_length (children);
+  if (children_count < tiles_count)
     {
-      for (column = 0; column < no_of_squares; column++)
+      /* add missing background tiles */
+      for (i = children_count; i < tiles_count; ++i)
         {
-          /* drawing square alternatively */
-          if ((row % 2 == 0 && column % 2 == 0) ||
-              (row % 2 != 0 && column % 2 != 0))
-            cairo_rectangle (cr,
-                column * CHAMPLAIN_BACKGROUND_TILE_SQUARE_SIZE,
-                row * CHAMPLAIN_BACKGROUND_TILE_SQUARE_SIZE,
-                CHAMPLAIN_BACKGROUND_TILE_SQUARE_SIZE,
-                CHAMPLAIN_BACKGROUND_TILE_SQUARE_SIZE);
+          ClutterActor *clone = clutter_texture_new ();
+          CoglHandle handle = clutter_texture_get_cogl_texture (priv->background_tile_actor);
+          clutter_texture_set_cogl_texture (CLUTTER_TEXTURE (clone), handle);
+
+          clutter_container_add_actor (CLUTTER_CONTAINER (priv->background_layer), clone);
+        }
+    }
+  else if (children_count > tiles_count)
+    {
+      /* remove extra background tiles */
+      for (i = tiles_count; i < children_count; ++i)
+        {
+          child = clutter_container_get_children (CLUTTER_CONTAINER (priv->background_layer));
+          clutter_container_remove_actor (CLUTTER_CONTAINER (priv->background_layer),
+              CLUTTER_ACTOR (child->data));
         }
-      cairo_fill (cr);
     }
-  cairo_stroke (cr);
-  cairo_destroy (cr);
 
-  return actor;
+  children = clutter_container_get_children (CLUTTER_CONTAINER (priv->background_layer));
+  child = children;
+  for (x = x_first; x < x_first + x_count; ++x)
+    {
+      for (y = y_first; y < y_first + y_count; ++y)
+        {
+          clutter_actor_set_position (CLUTTER_ACTOR (child->data),
+              (x * size) - priv->anchor_x,
+              (y * size) - priv->anchor_y);
+          child = g_list_next (child);
+        }
+    }
 }
 
+
 static void
 view_load_visible_tiles (ChamplainView *view)
 {
@@ -1958,8 +2001,7 @@ view_load_visible_tiles (ChamplainView *view)
   ChamplainViewPrivate *priv = view->priv;
   gint size;
   GList *children, *child;
-  gint children_count;
-  gint tiles_count, x_count, y_count, x_first, y_first, x_end, y_end, max_x_end, max_y_end;
+  gint x_count, y_count, x_first, y_first, x_end, y_end, max_x_end, max_y_end;
   gboolean *tile_map;
   gint arm_size, arm_max, turn;
   gint dirs[5] = { 0, 1, 0, -1, 0 };
@@ -2002,43 +2044,12 @@ view_load_visible_tiles (ChamplainView *view)
 
   DEBUG ("Range %d, %d to %d, %d", x_first, y_first, x_end, y_end);
 
-  tiles_count = x_count * y_count;
-  tile_map = g_slice_alloc0 (sizeof (gboolean) * tiles_count);
+  tile_map = g_slice_alloc0 (sizeof (gboolean) * x_count * y_count);
 
   /* fill background tiles */
-  children = clutter_container_get_children (CLUTTER_CONTAINER (priv->background_layer));
-  if (children == NULL)
-    children_count = 0;
-  else
-    children_count = g_list_length (children);
-  if (children_count < tiles_count)
-    {
-      /* add missing background tiles */
-      for (i = children_count; i < tiles_count; ++i)
-        clutter_container_add_actor (CLUTTER_CONTAINER (priv->background_layer),
-            CLUTTER_ACTOR (fill_background_tile (size)));
-    }
-  else if (children_count > tiles_count)
+  if (priv->background_tile_actor != NULL)
     {
-      /* remove extra background tiles */
-      for (i = 0, child = children ; i < (children_count - tiles_count) || child != NULL;
-              ++i, child = g_list_next (child))
-        clutter_container_remove_actor (CLUTTER_CONTAINER (priv->background_layer),
-            CLUTTER_ACTOR (CLUTTER_ACTOR (child->data)));
-    }
-
-  children = clutter_container_get_children (CLUTTER_CONTAINER (priv->background_layer));
-  if (children)
-    {
-      child = children;
-      for (x = x_first; x < x_end; ++x)
-        {
-          for (y = y_first; y < y_end; ++y)
-            {
-              view_position_background_tile (view, CLUTTER_ACTOR (child->data), x, y, size);
-              child = g_list_next (child);
-            }
-        }
+      fill_background_tiles (view);
     }
 
   /* Get rid of old tiles first */
@@ -2163,19 +2174,6 @@ view_position_tile (ChamplainView *view,
       (y * size) - priv->anchor_y);
 }
 
-static void
-view_position_background_tile (ChamplainView *view,
-    ClutterActor *actor,
-    gint x,
-    gint y,
-    gint size)
-{
-  ChamplainViewPrivate *priv = view->priv;
-
-  clutter_actor_set_position (actor,
-      (x * size) - priv->anchor_x,
-      (y * size) - priv->anchor_y);
-}
 
 static void
 remove_all_tiles (ChamplainView *view)
@@ -2513,6 +2511,55 @@ champlain_view_ensure_layers_visible (ChamplainView *view,
 }
 
 
+/**
+ * champlain_view_set_background_tile:
+ * @view: a #ChamplainView
+ * @background: The background texture
+ *
+ * Sets the background texture displayed behind the map.
+ *
+ * Since: 0.12.4
+ */
+void 
+champlain_view_set_background_tile (ChamplainView *view,
+    ClutterTexture *background)
+{
+  DEBUG_LOG ()
+
+  g_return_if_fail (CHAMPLAIN_IS_VIEW (view));
+
+  ChamplainViewPrivate *priv = view->priv;
+  
+  if (priv->background_tile_actor)
+    clutter_actor_destroy (CLUTTER_ACTOR (priv->background_tile_actor));
+
+  priv->background_tile_actor = g_object_ref_sink (background);
+}
+
+
+/**
+ * champlain_view_get_background_tile:
+ * @view: a #ChamplainView
+ *
+ * Gets the current background texture displayed behind the map.
+ *
+ * Returns: (transfer none): The texture.
+ * 
+ * Since: 0.12.4
+ */
+ClutterTexture *
+champlain_view_get_background_tile (ChamplainView *view)
+{
+  DEBUG_LOG ()
+
+  g_return_val_if_fail (CHAMPLAIN_IS_VIEW (view), NULL);
+
+  ChamplainViewPrivate *priv = view->priv;
+
+  return priv->background_tile_actor;
+}
+
+
 static void
 position_zoom_actor (ChamplainView *view)
 {
@@ -2633,7 +2680,7 @@ show_zoom_actor (ChamplainView *view,
 
   if (priv->animate_zoom)
     {
-      clutter_actor_set_opacity (priv->kinetic_scroll, 0);
+      clutter_actor_set_opacity (priv->map_layer, 0);
       
       clutter_group_remove_all (CLUTTER_GROUP (priv->zoom_layer));
 
@@ -2644,7 +2691,7 @@ show_zoom_actor (ChamplainView *view,
                 "scale-y", deltazoom,
                 NULL);
 
-      clutter_actor_animate (CLUTTER_ACTOR (priv->kinetic_scroll),
+      clutter_actor_animate (CLUTTER_ACTOR (priv->map_layer),
                 CLUTTER_EASE_IN_EXPO,
                 350,
                 "opacity", 255,
diff --git a/champlain/champlain-view.h b/champlain/champlain-view.h
index 68c779e..da490f4 100644
--- a/champlain/champlain-view.h
+++ b/champlain/champlain-view.h
@@ -117,12 +117,15 @@ void champlain_view_set_zoom_on_double_click (ChamplainView *view,
     gboolean value);
 void champlain_view_set_animate_zoom (ChamplainView *view,
     gboolean value);
+void champlain_view_set_background_tile (ChamplainView *view,
+    ClutterTexture *background);
 
 void champlain_view_add_layer (ChamplainView *view,
     ChamplainLayer *layer);
 void champlain_view_remove_layer (ChamplainView *view,
     ChamplainLayer *layer);
 
+
 guint champlain_view_get_zoom_level (ChamplainView *view);
 guint champlain_view_get_min_zoom_level (ChamplainView *view);
 guint champlain_view_get_max_zoom_level (ChamplainView *view);
@@ -133,6 +136,7 @@ gboolean champlain_view_get_keep_center_on_resize (ChamplainView *view);
 gboolean champlain_view_get_zoom_on_double_click (ChamplainView *view);
 gboolean champlain_view_get_animate_zoom (ChamplainView *view);
 ChamplainState champlain_view_get_state (ChamplainView *view);
+ClutterTexture *champlain_view_get_background_tile (ChamplainView *view);
 
 void champlain_view_reload_tiles (ChamplainView *view);
 
diff --git a/demos/launcher-gtk.c b/demos/launcher-gtk.c
index 7828036..828ab0b 100644
--- a/demos/launcher-gtk.c
+++ b/demos/launcher-gtk.c
@@ -27,6 +27,7 @@
 #define N_COLS 2
 #define COL_ID 0
 #define COL_NAME 1
+#define TILE_SQUARE_SIZE 8
 
 static ChamplainPathLayer *path_layer;
 static ChamplainPathLayer *path;
@@ -212,6 +213,52 @@ append_point (ChamplainPathLayer *layer, gdouble lon, gdouble lat)
 }
 
 
+static ClutterTexture *
+fill_background_tile (gint size)
+{
+  ClutterActor *actor = NULL;
+  cairo_t *cr;
+  cairo_pattern_t *pat;
+  gint no_of_squares = size / TILE_SQUARE_SIZE;
+  gint row, column;
+
+  actor = clutter_cairo_texture_new (size, size);
+
+  /* Create the background tile */
+  cr = clutter_cairo_texture_create (CLUTTER_CAIRO_TEXTURE (actor));
+  pat = cairo_pattern_create_linear (size / 2.0, 0.0, size, size / 2.0);
+  cairo_pattern_add_color_stop_rgb (pat, 0, 0.662, 0.662, 0.662);
+  cairo_set_source (cr, pat);
+  cairo_rectangle (cr, 0, 0, size, size);
+  cairo_fill (cr);
+  cairo_pattern_destroy (pat);
+
+  /* Filling the tile */
+  cairo_set_source_rgb (cr, 0.411, 0.411, 0.411);
+  cairo_set_line_cap (cr, CAIRO_LINE_CAP_ROUND);
+
+  for (row = 0; row < no_of_squares; ++row)
+    {
+      for (column = 0; column < no_of_squares; column++)
+        {
+          /* drawing square alternatively */
+          if ((row % 2 == 0 && column % 2 == 0) ||
+              (row % 2 != 0 && column % 2 != 0))
+            cairo_rectangle (cr,
+                column * TILE_SQUARE_SIZE,
+                row * TILE_SQUARE_SIZE,
+                TILE_SQUARE_SIZE,
+                TILE_SQUARE_SIZE);
+        }
+      cairo_fill (cr);
+    }
+  cairo_stroke (cr);
+  cairo_destroy (cr);
+
+  return CLUTTER_TEXTURE(actor);
+}
+
+
 int
 main (int argc,
     char *argv[])
@@ -222,6 +269,8 @@ main (int argc,
   ChamplainMarkerLayer *layer;
   ClutterActor *scale;
   ChamplainLicense *license_actor;
+  gint size;
+  ChamplainMapSource *map_source;
 
   if (gtk_clutter_init (&argc, &argv) != CLUTTER_INIT_SUCCESS)
     return 1;
@@ -271,6 +320,8 @@ main (int argc,
   layer = create_marker_layer (view, &path);
   champlain_view_add_layer (view, CHAMPLAIN_LAYER (path));
   champlain_view_add_layer (view, CHAMPLAIN_LAYER (layer));
+  
+  champlain_view_set_background_tile (view, fill_background_tile (256));
 
   path_layer = champlain_path_layer_new ();
   /* Cheap approx of Highway 10 */