New class ShellButtonBox

This is a Box subclass which adds several signals useful for implementing
"button like" behavior, such as hover and pressed states, as well as
click activation on release.

src/Makefile.am

@@ -57,6 +57,8 @@ libgnome_shell_la_SOURCES =			\
 	shell-app-system.h			\
 	shell-arrow.c			\
 	shell-arrow.h			\
+	shell-button-box.c           \
+	shell-button-box.h           \
 	shell-drawing.c            \
 	shell-drawing.h            \
 	shell-drawing-area.c			\

src/shell-button-box.c

@@ -0,0 +1,248 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
+
+/**
+ * SECTION:shell-button-box
+ * @short_description: A box with properties useful for implementing buttons
+ *
+ * A #BigBox subclass which translates lower-level Clutter button events
+ * into higher level properties which are useful for implementing "button-like"
+ * actors.
+ */
+
+#include "shell-button-box.h"
+
+G_DEFINE_TYPE(ShellButtonBox, shell_button_box, BIG_TYPE_BOX);
+
+struct _ShellButtonBoxPrivate {
+  gboolean held;
+  gboolean hover;
+  gboolean pressed;
+};
+
+/* Signals */
+enum
+{
+  ACTIVATE,
+  LAST_SIGNAL
+};
+
+enum {
+  PROP_0,
+
+  PROP_HOVER,
+  PROP_PRESSED,
+};
+
+static guint shell_button_box_signals [LAST_SIGNAL] = { 0 };
+
+static void
+set_hover (ShellButtonBox  *box,
+           gboolean         hover)
+{
+  if (box->priv->hover == hover)
+    return;
+  box->priv->hover = hover;
+  g_object_notify (G_OBJECT (box), "hover");
+}
+
+static void
+set_pressed (ShellButtonBox  *box,
+             gboolean         pressed)
+{
+  if (box->priv->pressed == pressed)
+    return;
+  box->priv->pressed = pressed;
+  g_object_notify (G_OBJECT (box), "pressed");
+}
+
+static gboolean
+shell_button_box_contains (ShellButtonBox     *box,
+                           ClutterActor       *actor)
+{
+  while (actor != NULL && actor != (ClutterActor*)box)
+    {
+      actor = clutter_actor_get_parent (actor);
+    }
+  return actor != NULL;
+}
+
+static gboolean
+shell_button_box_on_enter (ShellButtonBox     *box,
+                           ClutterEvent       *event,
+                           gpointer            user_data)
+{
+  if (shell_button_box_contains (box, event->crossing.related))
+    return TRUE;
+  if (!shell_button_box_contains (box, clutter_event_get_source (event)))
+    return TRUE;
+
+  set_hover (box, TRUE);
+  if (box->priv->held)
+    set_pressed (box, TRUE);
+
+  return TRUE;
+}
+
+static gboolean
+shell_button_box_on_leave (ShellButtonBox     *box,
+                           ClutterEvent       *event,
+                           gpointer            user_data)
+{
+  if (shell_button_box_contains (box, event->crossing.related))
+    return TRUE;
+
+  set_hover (box, FALSE);
+  set_pressed (box, FALSE);
+
+  return TRUE;
+}
+
+static gboolean
+shell_button_box_on_press (ShellButtonBox     *box,
+                           ClutterEvent       *event,
+                           gpointer            user_data)
+{
+  ClutterActor *source;
+
+  if (box->priv->held)
+    return TRUE;
+
+  source = clutter_event_get_source (event);
+  if (!shell_button_box_contains (box, source))
+    return FALSE;
+
+  box->priv->held = TRUE;
+  clutter_grab_pointer (CLUTTER_ACTOR (box));
+
+  set_pressed (box, TRUE);
+
+  return TRUE;
+}
+
+static gboolean
+shell_button_box_on_release (ShellButtonBox     *box,
+                             ClutterEvent       *event,
+                             gpointer            user_data)
+{
+  ClutterActor *source;
+
+  if (!box->priv->held)
+    return TRUE;
+
+  source = clutter_event_get_source (event);
+
+  box->priv->held = FALSE;
+  clutter_ungrab_pointer ();
+
+  if (!shell_button_box_contains (box, source))
+    return FALSE;
+
+  set_pressed (box, FALSE);
+
+  g_signal_emit (G_OBJECT (box), shell_button_box_signals[ACTIVATE], 0);
+
+  return TRUE;
+}
+
+static void
+shell_button_box_set_property(GObject         *object,
+                              guint            prop_id,
+                              const GValue    *value,
+                              GParamSpec      *pspec)
+{
+  switch (prop_id)
+    {
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static void
+shell_button_box_get_property(GObject         *object,
+                              guint            prop_id,
+                              GValue          *value,
+                              GParamSpec      *pspec)
+{
+  ShellButtonBox *box = SHELL_BUTTON_BOX (object);
+
+  switch (prop_id)
+    {
+    case PROP_PRESSED:
+      g_value_set_boolean (value, box->priv->pressed);
+      break;
+    case PROP_HOVER:
+      g_value_set_boolean (value, box->priv->hover);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static void
+shell_button_box_class_init (ShellButtonBoxClass *klass)
+{
+  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
+
+  gobject_class->get_property = shell_button_box_get_property;
+  gobject_class->set_property = shell_button_box_set_property;
+
+  /**
+   * ShellButtonBox::activate
+   * @box: The #ShellButtonBox
+   *
+   * This signal is emitted when the button should take the action
+   * associated with button click+release.
+   */
+  shell_button_box_signals[ACTIVATE] =
+    g_signal_new ("activate",
+                  G_TYPE_FROM_CLASS (klass),
+                  G_SIGNAL_RUN_LAST,
+                  0,
+                  NULL, NULL,
+                  g_cclosure_marshal_VOID__VOID,
+                  G_TYPE_NONE, 0);
+
+  /**
+   * ShellButtonBox:hover
+   *
+   * This property tracks whether the mouse is over the button; note this
+   * state is independent of whether the button is pressed.
+   */
+  g_object_class_install_property (gobject_class,
+                                   PROP_HOVER,
+                                   g_param_spec_boolean ("hover",
+                                                         "Hovering state",
+                                                         "Whether the mouse is over the button",
+                                                         FALSE,
+                                                         G_PARAM_READABLE));
+
+  /**
+   * ShellButtonBox:pressed
+   *
+   * This property tracks whether the button should have a "pressed in"
+   * effect.
+   */
+  g_object_class_install_property (gobject_class,
+                                   PROP_PRESSED,
+                                   g_param_spec_boolean ("pressed",
+                                                         "Pressed state",
+                                                         "Whether the button is currently pressed",
+                                                         FALSE,
+                                                         G_PARAM_READABLE));
+
+  g_type_class_add_private (gobject_class, sizeof (ShellButtonBoxPrivate));
+}
+
+static void
+shell_button_box_init (ShellButtonBox *self)
+{
+  self->priv = G_TYPE_INSTANCE_GET_PRIVATE (self, SHELL_TYPE_BUTTON_BOX,
+                                            ShellButtonBoxPrivate);
+
+  g_signal_connect (G_OBJECT (self), "enter-event", G_CALLBACK(shell_button_box_on_enter), NULL);
+  g_signal_connect (G_OBJECT (self), "leave-event", G_CALLBACK(shell_button_box_on_leave), NULL);
+  g_signal_connect (G_OBJECT (self), "button-press-event", G_CALLBACK(shell_button_box_on_press), NULL);
+  g_signal_connect (G_OBJECT (self), "button-release-event", G_CALLBACK(shell_button_box_on_release), NULL);
+}

src/shell-button-box.h

@@ -0,0 +1,33 @@
+#ifndef __SHELL_BUTTON_BOX_H__
+#define __SHELL_BUTTON_BOX_H__
+
+#include <clutter/clutter.h>
+#include "big/box.h"
+
+#define SHELL_TYPE_BUTTON_BOX                 (shell_button_box_get_type ())
+#define SHELL_BUTTON_BOX(obj)                 (G_TYPE_CHECK_INSTANCE_CAST ((obj), SHELL_TYPE_BUTTON_BOX, ShellButtonBox))
+#define SHELL_BUTTON_BOX_CLASS(klass)         (G_TYPE_CHECK_CLASS_CAST ((klass), SHELL_TYPE_BUTTON_BOX, ShellButtonBoxClass))
+#define SHELL_IS_BUTTON_BOX(obj)              (G_TYPE_CHECK_INSTANCE_TYPE ((obj), SHELL_TYPE_BUTTON_BOX))
+#define SHELL_IS_BUTTON_BOX_CLASS(klass)      (G_TYPE_CHECK_CLASS_TYPE ((klass), SHELL_TYPE_BUTTON_BOX))
+#define SHELL_BUTTON_BOX_GET_CLASS(obj)       (G_TYPE_INSTANCE_GET_CLASS ((obj), SHELL_TYPE_BUTTON_BOX, ShellButtonBoxClass))
+
+typedef struct _ShellButtonBox        ShellButtonBox;
+typedef struct _ShellButtonBoxClass   ShellButtonBoxClass;
+
+typedef struct _ShellButtonBoxPrivate ShellButtonBoxPrivate;
+
+struct _ShellButtonBox
+{
+    BigBox parent;
+
+    ShellButtonBoxPrivate *priv;
+};
+
+struct _ShellButtonBoxClass
+{
+    BigBoxClass parent_class;
+};
+
+GType shell_button_box_get_type (void) G_GNUC_CONST;
+
+#endif /* __SHELL_BUTTON_BOX_H__ */