bind-constraint: Add width and height binding

Allow using the BindConstraint to bind width and height of a source
actor.

Also, add a test for the BindConstraint showing all types of usages
for this constraint class.

clutter/clutter-bind-constraint.c

@@ -25,11 +25,56 @@
 /**
  * SECTION:clutter-bind-constraint
  * @Title: ClutterBindConstraint
- * @Short_Description: A constraint binding the position of an actor
+ * @Short_Description: A constraint binding the position or size of an actor
  *
- * #ClutterBindConstraint is a #ClutterConstraint that binds the position of
+ * #ClutterBindConstraint is a #ClutterConstraint that binds the
- * the #ClutterActor to which it is applied to the the position of another
+ * position or the size of the #ClutterActor to which it is applied
- * #ClutterActor.
+ * to the the position or the size of another #ClutterActor, or
+ * "source".
+ *
+ * An offset can be applied to the constraint, to avoid overlapping. The offset
+ * can also be animated. For instance, the following code will set up three
+ * actors to be bound to the same origin:
+ *
+ * |[
+ * /* source */
+ * rect[0] = clutter_rectangle_new_with_color (&red_color);
+ * clutter_actor_set_position (rect[0], x_pos, y_pos);
+ * clutter_actor_set_size (rect[0], 100, 100);
+ *
+ * /* second rectangle */
+ * rect[1] = clutter_rectangle_new_with_color (&green_color);
+ * clutter_actor_set_size (rect[1], 100, 100);
+ * clutter_actor_set_opacity (rect[1], 0);
+ *
+ * constraint = clutter_bind_constraint_new (rect[0], CLUTTER_BIND_X, 0.0);
+ * clutter_actor_add_constraint_with_name (rect[1], "green-x", constraint);
+ * constraint = clutter_bind_constraint_new (rect[0], CLUTTER_BIND_Y, 0.0);
+ * clutter_actor_add_constraint_with_name (rect[1], "green-y", constraint);
+ *
+ * /* third rectangle */
+ * rect[2] = clutter_rectangle_new_with_color (&blue_color);
+ * clutter_actor_set_size (rect[2], 100, 100);
+ * clutter_actor_set_opacity (rect[2], 0);
+ *
+ * constraint = clutter_bind_constraint_new (rect[0], CLUTTER_BIND_X, 0.0);
+ * clutter_actor_add_constraint_with_name (rect[2], "blue-x", constraint);
+ * constraint = clutter_bind_constraint_new (rect[0], CLUTTER_BIND_Y, 0.0);
+ * ]|
+ *
+ * The following code animates the second and third rectangles to "expand"
+ * them horizontally from underneath the first rectangle:
+ *
+ * |[
+ * clutter_actor_animate (rect[1], CLUTTER_EASE_OUT_CUBIC, 250,
+ *                        "@constraints.green-x.offset", 100.0,
+ *                        "opacity", 255,
+ *                        NULL);
+ * clutter_actor_animate (rect[2], CLUTTER_EASE_OUT_CUBIC, 250,
+ *                        "@constraints.blue-x.offset", 200.0,
+ *                        "opacity", 255,
+ *                        NULL);
+ * ]|
  *
  * #ClutterBindConstraint is available since Clutter 1.4
  */
@@ -79,8 +124,9 @@ G_DEFINE_TYPE (ClutterBindConstraint,
                CLUTTER_TYPE_CONSTRAINT);
 
 static void
-update_actor_position (ClutterBindConstraint *bind)
+update_actor_coords (ClutterBindConstraint *bind)
 {
+  gfloat source_width, source_height;
   ClutterVertex source_position;
   ClutterActor *actor;
 
@@ -97,6 +143,7 @@ update_actor_position (ClutterBindConstraint *bind)
   source_position.x = clutter_actor_get_x (bind->source);
   source_position.y = clutter_actor_get_y (bind->source);
   source_position.z = clutter_actor_get_depth (bind->source);
+  clutter_actor_get_size (bind->source, &source_width, &source_height);
 
   switch (bind->coordinate)
     {
@@ -111,20 +158,32 @@ update_actor_position (ClutterBindConstraint *bind)
     case CLUTTER_BIND_Z:
       clutter_actor_set_depth (actor, source_position.z + bind->offset);
       break;
+
+    case CLUTTER_BIND_WIDTH:
+      clutter_actor_set_width (actor, source_width + bind->offset);
+      break;
+
+    case CLUTTER_BIND_HEIGHT:
+      clutter_actor_set_height (actor, source_height + bind->offset);
+      break;
     }
 }
 
 static void
-source_position_changed (GObject               *gobject,
+source_allocation_changed (ClutterActor           *source,
+                           const ClutterActorBox  *allocation,
+                           ClutterAllocationFlags  flags,
+                           ClutterBindConstraint  *bind)
+{
+  update_actor_coords (bind);
+}
+
+static void
+source_depth_changed (GObject               *gobject,
                       GParamSpec            *pspec,
                       ClutterBindConstraint *bind)
 {
-  if (strcmp (pspec->name, "x") == 0 ||
+  update_actor_coords (bind);
-      strcmp (pspec->name, "y") == 0 ||
-      strcmp (pspec->name, "depth") == 0)
-    {
-      update_actor_position (bind);
-    }
 }
 
 static void
@@ -308,21 +367,27 @@ clutter_bind_constraint_set_source (ClutterBindConstraint *constraint,
                                             G_CALLBACK (source_destroyed),
                                             constraint);
       g_signal_handlers_disconnect_by_func (old_source,
-                                            G_CALLBACK (source_position_changed),
+                                            G_CALLBACK (source_allocation_changed),
+                                            constraint);
+      g_signal_handlers_disconnect_by_func (old_source,
+                                            G_CALLBACK (source_depth_changed),
                                             constraint);
     }
 
   constraint->source = source;
   if (constraint->source != NULL)
     {
-      g_signal_connect (constraint->source, "notify",
+      g_signal_connect (constraint->source, "allocation-changed",
-                        G_CALLBACK (source_position_changed),
+                        G_CALLBACK (source_allocation_changed),
+                        constraint);
+      g_signal_connect (constraint->source, "notify::depth",
+                        G_CALLBACK (source_depth_changed),
                         constraint);
       g_signal_connect (constraint->source, "destroy",
                         G_CALLBACK (source_destroyed),
                         constraint);
 
-      update_actor_position (constraint);
+      update_actor_coords (constraint);
     }
 
   g_object_notify (G_OBJECT (constraint), "source");
@@ -366,7 +431,7 @@ clutter_bind_constraint_set_coordinate (ClutterBindConstraint *constraint,
 
   constraint->coordinate = coordinate;
 
-  update_actor_position (constraint);
+  update_actor_coords (constraint);
 
   g_object_notify (G_OBJECT (constraint), "coordinate");
 }
@@ -410,7 +475,7 @@ clutter_bind_constraint_set_offset (ClutterBindConstraint *constraint,
 
   constraint->offset = offset;
 
-  update_actor_position (constraint);
+  update_actor_coords (constraint);
 
   g_object_notify (G_OBJECT (constraint), "offset");
 }

clutter/clutter-bind-constraint.h

@@ -52,15 +52,19 @@ typedef struct _ClutterBindConstraint   ClutterBindConstraint;
  * @CLUTTER_BIND_X: Bind the X coordinate
  * @CLUTTER_BIND_Y: Bind the Y coordinate
  * @CLUTTER_BIND_Z: Bind the Z coordinate
+ * @CLUTTER_BIND_WIDTH: Bind the width
+ * @CLUTTER_BIND_HEIGHT: Bidng the height
  *
- * Specifies which coordinate should be used in a binding
+ * Specifies which property should be used in a binding
  *
  * Since: 1.4
  */
 typedef enum { /*< prefix=CLUTTER_BIND >*/
   CLUTTER_BIND_X,
   CLUTTER_BIND_Y,
-  CLUTTER_BIND_Z
+  CLUTTER_BIND_Z,
+  CLUTTER_BIND_WIDTH,
+  CLUTTER_BIND_HEIGHT
 } ClutterBindCoordinate;
 
 GType clutter_bind_constraint_get_type (void) G_GNUC_CONST;

tests/interactive/.gitignore

@@ -67,3 +67,4 @@
 /test-state
 /test-state-animator
 /test-scrolling
+/test-bind

tests/interactive/Makefile.am

@@ -53,7 +53,8 @@ UNIT_TESTS = \
 	test-stage-sizing.c \
 	test-drag.c \
 	test-constraints.c \
-	test-scrolling.c
+	test-scrolling.c \
+	test-bind.c
 
 if X11_TESTS
 UNIT_TESTS += test-pixmap.c

tests/interactive/test-bind.c

@@ -0,0 +1,110 @@
+#include <stdlib.h>
+#include <gmodule.h>
+#include <clutter/clutter.h>
+
+#define RECT_SIZE       128.0
+
+#define N_COLORS        3
+
+static ClutterActor *rects[N_COLORS] = { NULL, };
+static const gchar *colors[N_COLORS] = {
+  "#cc0000", "#3465a4", "#73d216"
+};
+static gboolean is_expanded = FALSE;
+
+static void
+on_click (ClutterClickAction *action,
+          ClutterActor       *actor)
+{
+  if (!is_expanded)
+    {
+      clutter_actor_animate (rects[1], CLUTTER_EASE_OUT_CUBIC, 250,
+                             "@constraints.green-x.offset", RECT_SIZE,
+                             "opacity", 255,
+                             NULL);
+      clutter_actor_animate (rects[2], CLUTTER_EASE_OUT_CUBIC, 500,
+                             "@constraints.blue-x.offset", (RECT_SIZE * 2.0 + 0.5),
+                             "opacity", 255,
+                             NULL);
+    }
+  else
+    {
+      clutter_actor_animate (rects[1], CLUTTER_EASE_OUT_CUBIC, 250,
+                             "@constraints.green-x.offset", 0.0,
+                             "opacity", 0,
+                             NULL);
+      clutter_actor_animate (rects[2], CLUTTER_EASE_OUT_CUBIC, 250,
+                             "@constraints.blue-x.offset", 0.0,
+                             "opacity", 0,
+                             NULL);
+    }
+
+  is_expanded = !is_expanded;
+}
+
+G_MODULE_EXPORT int
+test_bind_main (int argc, char *argv[])
+{
+  ClutterActor *stage;
+  ClutterConstraint *constraint;
+  ClutterAction *action;
+  ClutterColor color;
+
+  clutter_init (&argc, &argv);
+
+  stage = clutter_stage_new ();
+  clutter_stage_set_title (CLUTTER_STAGE (stage), "Bind Constraint");
+  clutter_stage_set_user_resizable (CLUTTER_STAGE (stage), TRUE);
+  clutter_actor_set_size (stage, RECT_SIZE * 4.0, RECT_SIZE * 3.0);
+  g_signal_connect (stage, "destroy", G_CALLBACK (clutter_main_quit), NULL);
+
+  /* main rectangle */
+  clutter_color_from_string (&color, colors[0]);
+  rects[0] = clutter_rectangle_new_with_color (&color);
+  clutter_actor_set_size (rects[0], RECT_SIZE, RECT_SIZE);
+
+  /* center it on the stage */
+  clutter_actor_add_constraint (rects[0], clutter_align_constraint_new (stage, CLUTTER_ALIGN_X_AXIS, 0.1));
+  clutter_actor_add_constraint (rects[0], clutter_align_constraint_new (stage, CLUTTER_ALIGN_Y_AXIS, 0.5));
+
+  /* make it clickable */
+  action = clutter_click_action_new ();
+  clutter_actor_add_action (rects[0], action);
+  clutter_actor_set_reactive (rects[0], TRUE);
+  g_signal_connect (action, "clicked", G_CALLBACK (on_click), NULL);
+
+  /* second rectangle */
+  clutter_color_from_string (&color, colors[1]);
+  rects[1] = clutter_rectangle_new_with_color (&color);
+  clutter_actor_set_opacity (rects[1], 0);
+  clutter_actor_add_constraint (rects[1], clutter_bind_constraint_new (rects[0], CLUTTER_BIND_WIDTH, 0.0));
+  clutter_actor_add_constraint (rects[1], clutter_bind_constraint_new (rects[0], CLUTTER_BIND_HEIGHT, 0.0));
+  constraint = clutter_bind_constraint_new (rects[0], CLUTTER_BIND_X, 0.0);
+  clutter_actor_add_constraint_with_name (rects[1], "green-x", constraint);
+  constraint = clutter_bind_constraint_new (rects[0], CLUTTER_BIND_Y, 0.0);
+  clutter_actor_add_constraint_with_name (rects[1], "green-y", constraint);
+
+  /* third rectangle */
+  clutter_color_from_string (&color, colors[2]);
+  rects[2] = clutter_rectangle_new_with_color (&color);
+  clutter_actor_set_opacity (rects[2], 0);
+  clutter_actor_add_constraint (rects[2], clutter_bind_constraint_new (rects[0], CLUTTER_BIND_WIDTH, 0.0));
+  clutter_actor_add_constraint (rects[2], clutter_bind_constraint_new (rects[0], CLUTTER_BIND_HEIGHT, 0.0));
+  constraint = clutter_bind_constraint_new (rects[0], CLUTTER_BIND_X, 0.0);
+  clutter_actor_add_constraint_with_name (rects[2], "blue-x", constraint);
+  constraint = clutter_bind_constraint_new (rects[0], CLUTTER_BIND_Y, 0.0);
+  clutter_actor_add_constraint_with_name (rects[2], "blue-y", constraint);
+
+  /* add everything to the stage */
+  clutter_container_add (CLUTTER_CONTAINER (stage),
+                         rects[2],
+                         rects[1],
+                         rects[0],
+                         NULL);
+
+  clutter_actor_show (stage);
+
+  clutter_main ();
+
+  return EXIT_SUCCESS;
+}