mutter/doc/cookbook/examples/layouts-bind-constraint-overlay.c

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#include <stdlib.h>
#include <clutter/clutter.h>
#define STAGE_SIDE 400
#define RECTANGLE_SIDE STAGE_SIDE * 0.5
#define TEXTURE_SIZE_MAX STAGE_SIDE * 0.9
#define TEXTURE_SIZE_MIN STAGE_SIDE * 0.1
#define TEXTURE_SIZE_STEP 0.2
#define OVERLAY_OPACITY_OFF 0
#define OVERLAY_OPACITY_ON 100
static const ClutterColor stage_color = { 0x33, 0x33, 0x55, 0xff };
static const ClutterColor overlay_color = { 0xaa, 0x99, 0x00, 0xff };
/* change the texture size with +/- */
static gboolean
key_press_cb (ClutterActor *actor,
ClutterEvent *event,
gpointer user_data)
{
ClutterActor *texture;
gfloat texture_width, texture_height;
guint key_pressed;
texture = CLUTTER_ACTOR (user_data);
clutter_actor_get_size (texture, &texture_width, &texture_height);
key_pressed = clutter_event_get_key_symbol (event);
if (key_pressed == CLUTTER_KEY_plus)
{
texture_width *= 1.0 + TEXTURE_SIZE_STEP;
texture_height *= 1.0 + TEXTURE_SIZE_STEP;
}
else if (key_pressed == CLUTTER_KEY_minus)
{
texture_width *= 1.0 - TEXTURE_SIZE_STEP;
texture_height *= 1.0 - TEXTURE_SIZE_STEP;
}
if (texture_width <= TEXTURE_SIZE_MAX && texture_width >= TEXTURE_SIZE_MIN)
clutter_actor_animate (texture, CLUTTER_EASE_OUT_CUBIC, 500,
"width", texture_width,
"height", texture_height,
NULL);
return TRUE;
}
/* turn overlay opacity on/off */
static void
click_cb (ClutterClickAction *action,
ClutterActor *actor,
gpointer user_data)
{
ClutterActor *overlay = CLUTTER_ACTOR (user_data);
guint8 opacity = clutter_actor_get_opacity (overlay);
if (opacity < OVERLAY_OPACITY_ON)
opacity = OVERLAY_OPACITY_ON;
else
opacity = OVERLAY_OPACITY_OFF;
clutter_actor_set_opacity (overlay, opacity);
}
int
main (int argc, char *argv[])
{
ClutterActor *stage;
ClutterActor *texture;
ClutterActor *overlay;
ClutterAction *click;
GError *error = NULL;
gchar *filename = TESTS_DATA_DIR "/redhand.png";
if (argc > 1)
filename = argv[1];
clutter_init (&argc, &argv);
stage = clutter_stage_new ();
clutter_actor_set_size (stage, STAGE_SIDE, STAGE_SIDE);
clutter_stage_set_color (CLUTTER_STAGE (stage), &stage_color);
g_signal_connect (stage, "destroy", G_CALLBACK (clutter_main_quit), NULL);
texture = clutter_texture_new ();
clutter_texture_set_keep_aspect_ratio (CLUTTER_TEXTURE (texture), TRUE);
clutter_actor_set_reactive (texture, TRUE);
clutter_actor_set_size (texture, RECTANGLE_SIDE, RECTANGLE_SIDE);
clutter_actor_add_constraint (texture, clutter_align_constraint_new (stage, CLUTTER_ALIGN_X_AXIS, 0.5));
clutter_actor_add_constraint (texture, clutter_align_constraint_new (stage, CLUTTER_ALIGN_Y_AXIS, 0.5));
clutter_texture_set_from_file (CLUTTER_TEXTURE (texture),
filename,
&error);
if (error != NULL)
{
g_warning ("Error loading %s\n%s", filename, error->message);
g_error_free (error);
exit (EXIT_FAILURE);
}
/* overlay is 10px wider and taller than the texture, and centered on it;
* initially, it is transparent; but it is made semi-opaque when the
* texture is clicked
*/
overlay = clutter_rectangle_new_with_color (&overlay_color);
clutter_actor_set_opacity (overlay, OVERLAY_OPACITY_OFF);
clutter_actor_add_constraint (overlay, clutter_bind_constraint_new (texture, CLUTTER_BIND_WIDTH, 10));
clutter_actor_add_constraint (overlay, clutter_bind_constraint_new (texture, CLUTTER_BIND_HEIGHT, 10));
clutter_actor_add_constraint (overlay, clutter_align_constraint_new (texture, CLUTTER_ALIGN_X_AXIS, 0.5));
clutter_actor_add_constraint (overlay, clutter_align_constraint_new (texture, CLUTTER_ALIGN_Y_AXIS, 0.5));
click = clutter_click_action_new ();
clutter_actor_add_action (texture, click);
clutter_container_add (CLUTTER_CONTAINER (stage), texture, overlay, NULL);
clutter_actor_raise_top (overlay);
g_signal_connect (click, "clicked", G_CALLBACK (click_cb), overlay);
g_signal_connect (stage,
"key-press-event",
G_CALLBACK (key_press_cb),
texture);
clutter_actor_show (stage);
clutter_main ();
return EXIT_SUCCESS;
}