cookbook: Example of simple handling of button events

Added an example showing how to examine the content
of a ClutterButtonEvent in a signal handler.

doc/cookbook/examples/Makefile.am

@@ -28,6 +28,7 @@ noinst_PROGRAMS = \
 	textures-crossfade-slideshow	\
 	script-ui	\
 	script-signals	\
+	events-buttons	\
 	$(NULL)
 
 INCLUDES = \
@@ -76,5 +77,6 @@ textures_crossfade_cogl_SOURCES            = textures-crossfade-cogl.c
 textures_crossfade_slideshow_SOURCES       = textures-crossfade-slideshow.c
 script_ui_SOURCES                          = script-ui.c
 script_signals_SOURCES                     = script-signals.c
+events_buttons_SOURCES                     = events-buttons.c
 
 -include $(top_srcdir)/build/autotools/Makefile.am.gitignore

doc/cookbook/examples/events-buttons.c

@@ -0,0 +1,107 @@
+#include <stdlib.h>
+#include <clutter/clutter.h>
+
+static const ClutterColor stage_color = { 0x33, 0x33, 0x55, 0xff };
+static const ClutterColor red_color = { 0xff, 0x00, 0x00, 0xff };
+static const ClutterColor green_color = { 0x00, 0xff, 0x00, 0xff };
+
+static gboolean
+button_event_cb (ClutterActor *actor,
+                 ClutterEvent *event,
+                 gpointer      user_data)
+{
+  gfloat x, y;
+  gchar *event_type;
+  guint button_pressed;
+  ClutterModifierType state;
+  gchar *ctrl_pressed;
+  guint32 click_count;
+
+  /* where the pointer was when the button event occurred */
+  clutter_event_get_coords (event, &x, &y);
+
+  /* check whether it was a press or release event */
+  event_type = "released";
+  if (clutter_event_type (event) == CLUTTER_BUTTON_PRESS)
+    event_type = "pressed";
+
+  /* which button triggered the event */
+  button_pressed = clutter_event_get_button (event);
+
+  /* keys down when the button was pressed */
+  state = clutter_event_get_state (event);
+
+  ctrl_pressed = "ctrl not pressed";
+  if (state & CLUTTER_CONTROL_MASK)
+    ctrl_pressed = "ctrl pressed";
+
+  /* click count */
+  click_count = clutter_event_get_click_count (event);
+
+  g_debug ("button %d %s at %.0f,%.0f; %s; click count %d",
+           button_pressed,
+           event_type,
+           x,
+           y,
+           ctrl_pressed,
+           click_count);
+
+  return TRUE;
+}
+
+int
+main (int   argc,
+      char *argv[])
+{
+  ClutterActor *stage;
+  ClutterActor *red;
+  ClutterActor *green;
+
+  clutter_init (&argc, &argv);
+
+  stage = clutter_stage_get_default ();
+  clutter_actor_set_size (stage, 400, 400);
+  clutter_stage_set_color (CLUTTER_STAGE (stage), &stage_color);
+  g_signal_connect (stage, "destroy", G_CALLBACK (clutter_main_quit), NULL);
+
+  red = clutter_rectangle_new_with_color (&red_color);
+  clutter_actor_set_size (red, 100, 100);
+  clutter_actor_set_position (red, 50, 150);
+  clutter_actor_set_reactive (red, TRUE);
+
+  green = clutter_rectangle_new_with_color (&green_color);
+  clutter_actor_set_size (green, 100, 100);
+  clutter_actor_set_position (green, 250, 150);
+  clutter_actor_set_reactive (green, TRUE);
+
+  g_signal_connect (red,
+                    "button-press-event",
+                    G_CALLBACK (button_event_cb),
+                    NULL);
+
+  g_signal_connect (red,
+                    "button-release-event",
+                    G_CALLBACK (button_event_cb),
+                    NULL);
+
+  g_signal_connect (green,
+                    "button-press-event",
+                    G_CALLBACK (button_event_cb),
+                    NULL);
+
+  g_signal_connect (green,
+                    "button-release-event",
+                    G_CALLBACK (button_event_cb),
+                    NULL);
+
+  clutter_container_add (CLUTTER_CONTAINER (stage),
+                         red,
+                         green,
+                         NULL);
+
+  clutter_actor_show (stage);
+
+  clutter_main ();
+
+  return EXIT_SUCCESS;
+}