cookbook: Added example to show how stacking affects pointer events
Added another example (used for a screenshot) to demonstrate how pointer events pass through non-reactive actors and how depth ordering affects whether an actor will emit a pointer motion signal.
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@ -13,6 +13,7 @@ noinst_PROGRAMS = \
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events-mouse-scroll \
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events-mouse-scroll \
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events-pointer-motion \
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events-pointer-motion \
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events-pointer-motion-crossing \
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events-pointer-motion-crossing \
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events-pointer-motion-stacked \
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events-pointer-motion-scribbler \
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events-pointer-motion-scribbler \
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$(NULL)
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$(NULL)
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@ -45,6 +46,7 @@ layouts_stacking_diff_sized_actors_SOURCES = layouts-stacking-diff-sized-actors.
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events_mouse_scroll_SOURCES = events-mouse-scroll.c
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events_mouse_scroll_SOURCES = events-mouse-scroll.c
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events_pointer_motion_SOURCES = events-pointer-motion.c
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events_pointer_motion_SOURCES = events-pointer-motion.c
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events_pointer_motion_crossing_SOURCES = events-pointer-motion-crossing.c
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events_pointer_motion_crossing_SOURCES = events-pointer-motion-crossing.c
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events_pointer_motion_stacked_SOURCES = events-pointer-motion-stacked.c
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events_pointer_motion_scribbler_SOURCES = events-pointer-motion-scribbler.c
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events_pointer_motion_scribbler_SOURCES = events-pointer-motion-scribbler.c
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-include $(top_srcdir)/build/autotools/Makefile.am.gitignore
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-include $(top_srcdir)/build/autotools/Makefile.am.gitignore
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90
doc/cookbook/examples/events-pointer-motion-stacked.c
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90
doc/cookbook/examples/events-pointer-motion-stacked.c
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@ -0,0 +1,90 @@
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/*
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* Testing what happens with a stack of actors and pointer events
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* red and green are reactive; blue is not
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*
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* when the pointer is over green (even if green is obscured by blue)
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* signals are emitted by green (not by blue);
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*
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* but when the pointer is over the overlap between red and green,
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* signals are emitted by green
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*
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* gcc -g -O0 -o stacked-actors-and-events stacked-actors-and-events.c `pkg-config --libs --cflags clutter-1.0 glib-2.0` -lm
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*/
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#include <clutter/clutter.h>
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static const ClutterColor stage_color = { 0x33, 0x33, 0x55, 0xff };
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static const ClutterColor red = { 0xff, 0x00, 0x00, 0xff };
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static const ClutterColor green = { 0x00, 0xff, 0x00, 0xff };
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static const ClutterColor blue = { 0x00, 0x00, 0xff, 0xff };
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static gboolean
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_pointer_motion_cb (ClutterActor *actor,
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ClutterEvent *event,
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gpointer user_data)
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{
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/* get the coordinates where the pointer crossed into the actor */
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gfloat stage_x, stage_y;
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clutter_event_get_coords (event, &stage_x, &stage_y);
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/*
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* as the coordinates are relative to the stage, rather than
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* the actor which emitted the signal, it can be useful to
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* transform them to actor-relative coordinates
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*/
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gfloat actor_x, actor_y;
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clutter_actor_transform_stage_point (actor,
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stage_x, stage_y,
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&actor_x, &actor_y);
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g_debug ("pointer on actor %s @ x %.0f, y %.0f",
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clutter_actor_get_name (actor),
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actor_x, actor_y);
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return TRUE;
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}
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int
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main (int argc, char *argv[])
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{
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ClutterActor *stage;
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ClutterActor *r1, *r2, *r3;
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clutter_init (&argc, &argv);
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stage = clutter_stage_get_default ();
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clutter_actor_set_size (stage, 300, 300);
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clutter_stage_set_color (CLUTTER_STAGE (stage), &stage_color);
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r1 = clutter_rectangle_new_with_color (&red);
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clutter_actor_set_size (r1, 150, 150);
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clutter_actor_add_constraint (r1, clutter_align_constraint_new (stage, CLUTTER_ALIGN_X_AXIS, 0.25));
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clutter_actor_add_constraint (r1, clutter_align_constraint_new (stage, CLUTTER_ALIGN_Y_AXIS, 0.25));
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clutter_actor_set_reactive (r1, TRUE);
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clutter_actor_set_name (r1, "red");
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r2 = clutter_rectangle_new_with_color (&green);
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clutter_actor_set_size (r2, 150, 150);
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clutter_actor_add_constraint (r2, clutter_align_constraint_new (stage, CLUTTER_ALIGN_X_AXIS, 0.5));
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clutter_actor_add_constraint (r2, clutter_align_constraint_new (stage, CLUTTER_ALIGN_Y_AXIS, 0.5));
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clutter_actor_set_reactive (r2, TRUE);
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clutter_actor_set_depth (r2, -100);
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clutter_actor_set_name (r2, "green");
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r3 = clutter_rectangle_new_with_color (&blue);
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clutter_actor_set_size (r3, 150, 150);
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clutter_actor_add_constraint (r3, clutter_align_constraint_new (stage, CLUTTER_ALIGN_X_AXIS, 0.75));
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clutter_actor_add_constraint (r3, clutter_align_constraint_new (stage, CLUTTER_ALIGN_Y_AXIS, 0.75));
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clutter_actor_set_opacity (r3, 125.5);
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clutter_actor_set_name (r3, "blue");
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clutter_container_add (CLUTTER_CONTAINER (stage), r1, r2, r3, NULL);
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g_signal_connect (r1, "motion-event", G_CALLBACK (_pointer_motion_cb), NULL);
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g_signal_connect (r2, "motion-event", G_CALLBACK (_pointer_motion_cb), NULL);
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clutter_actor_show (stage);
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clutter_main ();
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return 0;
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}
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