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#include <stdlib.h>
#include <math.h>
#include <cairo.h>
#include <clutter/clutter.h>
static gboolean
draw_clock (ClutterCanvas *canvas,
cairo_t *cr,
int width,
int height)
{
GDateTime *now;
float hours, minutes, seconds;
ClutterColor color;
/* get the current time and compute the angles */
now = g_date_time_new_now_local ();
seconds = g_date_time_get_second (now) * G_PI / 30;
minutes = g_date_time_get_minute (now) * G_PI / 30;
hours = g_date_time_get_hour (now) * G_PI / 6;
cairo_save (cr);
/* clear the contents of the canvas, to avoid painting
* over the previous frame
*/
cairo_set_operator (cr, CAIRO_OPERATOR_CLEAR);
cairo_paint (cr);
cairo_restore (cr);
cairo_set_operator (cr, CAIRO_OPERATOR_OVER);
/* scale the modelview to the size of the surface */
cairo_scale (cr, width, height);
cairo_set_line_cap (cr, CAIRO_LINE_CAP_ROUND);
cairo_set_line_width (cr, 0.1);
/* the black rail that holds the seconds indicator */
clutter_cairo_set_source_color (cr, CLUTTER_COLOR_Black);
cairo_translate (cr, 0.5, 0.5);
cairo_arc (cr, 0, 0, 0.4, 0, G_PI * 2);
cairo_stroke (cr);
/* the seconds indicator */
color = *CLUTTER_COLOR_White;
color.alpha = 128;
clutter_cairo_set_source_color (cr, &color);
cairo_move_to (cr, 0, 0);
cairo_arc (cr, sinf (seconds) * 0.4, - cosf (seconds) * 0.4, 0.05, 0, G_PI * 2);
cairo_fill (cr);
/* the minutes hand */
color = *CLUTTER_COLOR_DarkChameleon;
color.alpha = 196;
clutter_cairo_set_source_color (cr, &color);
cairo_move_to (cr, 0, 0);
cairo_line_to (cr, sinf (minutes) * 0.4, -cosf (minutes) * 0.4);
cairo_stroke (cr);
/* the hours hand */
cairo_move_to (cr, 0, 0);
cairo_line_to (cr, sinf (hours) * 0.2, -cosf (hours) * 0.2);
cairo_stroke (cr);
g_date_time_unref (now);
/* we're done drawing */
return TRUE;
}
static gboolean
invalidate_clock (gpointer data_)
{
/* invalidate the contents of the canvas */
clutter_content_invalidate (data_);
/* keep the timeout source */
return G_SOURCE_CONTINUE;
}
static guint idle_resize_id;
static gboolean
idle_resize (gpointer data)
{
ClutterActor *actor = data;
float width, height;
/* match the canvas size to the actor's */
clutter_actor_get_size (actor, &width, &height);
clutter_canvas_set_size (CLUTTER_CANVAS (clutter_actor_get_content (actor)),
ceilf (width),
ceilf (height));
/* unset the guard */
idle_resize_id = 0;
/* remove the timeout */
return G_SOURCE_REMOVE;
}
static void
on_actor_resize (ClutterActor *actor,
const ClutterActorBox *allocation,
ClutterAllocationFlags flags,
gpointer user_data)
{
/* throttle multiple actor allocations to one canvas resize; we use a guard
* variable to avoid queueing multiple resize operations
*/
if (idle_resize_id == 0)
idle_resize_id = clutter_threads_add_timeout (1000, idle_resize, actor);
}
int
main (int argc, char *argv[])
{
ClutterActor *stage, *actor;
ClutterContent *canvas;
/* initialize Clutter */
if (clutter_init (&argc, &argv) != CLUTTER_INIT_SUCCESS)
return EXIT_FAILURE;
/* create a resizable stage */
stage = clutter_stage_new ();
clutter_stage_set_title (CLUTTER_STAGE (stage), "2D Clock");
clutter_stage_set_user_resizable (CLUTTER_STAGE (stage), TRUE);
clutter_actor_set_background_color (stage, CLUTTER_COLOR_LightSkyBlue);
clutter_actor_set_size (stage, 300, 300);
clutter_actor_show (stage);
/* our 2D canvas, courtesy of Cairo */
canvas = clutter_canvas_new ();
clutter_canvas_set_size (CLUTTER_CANVAS (canvas), 300, 300);
actor = clutter_actor_new ();
clutter_actor_set_content (actor, canvas);
clutter_actor_set_content_scaling_filters (actor,
CLUTTER_SCALING_FILTER_TRILINEAR,
CLUTTER_SCALING_FILTER_LINEAR);
clutter_actor_add_child (stage, actor);
/* the actor now owns the canvas */
g_object_unref (canvas);
/* bind the size of the actor to that of the stage */
clutter_actor_add_constraint (actor, clutter_bind_constraint_new (stage, CLUTTER_BIND_SIZE, 0));
/* resize the canvas whenever the actor changes size */
g_signal_connect (actor, "allocation-changed", G_CALLBACK (on_actor_resize), NULL);
/* quit on destroy */
g_signal_connect (stage, "destroy", G_CALLBACK (clutter_main_quit), NULL);
/* connect our drawing code */
g_signal_connect (canvas, "draw", G_CALLBACK (draw_clock), NULL);
/* invalidate the canvas, so that we can draw before the main loop starts */
clutter_content_invalidate (canvas);
/* set up a timer that invalidates the canvas every second */
clutter_threads_add_timeout (1000, invalidate_clock, canvas);
clutter_main ();
return EXIT_SUCCESS;
}
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