/**
* clutter_event_get_angle:
* @source: a #ClutterEvent
* @target: a #ClutterEvent
*
* Retrieves the angle relative from @source to @target.
*
* The direction of the angle is from the position X axis towards
* the positive Y axis.
*
* Return value: the angle between two #ClutterEvent
*
* Since: 1.12
*/
double
clutter_event_get_angle (const ClutterEvent *source,
const ClutterEvent *target)
{
ClutterPoint p0, p1;
float x_distance, y_distance;
double angle;
clutter_event_get_position (source, &p0);
clutter_event_get_position (target, &p1);
if (clutter_point_equals (&p0, &p1))
return 0;
clutter_point_distance (&p0, &p1, &x_distance, &y_distance);
angle = atan2 (x_distance, y_distance);
/* invert the angle, and shift it by 90 degrees */
angle = (2.0 * G_PI) - angle;
angle += G_PI / 2.0;
/* keep the angle within the [ 0, 360 ] interval */
angle = fmod (angle, 2.0 * G_PI);
return angle;
}
/**
* clutter_point_distance:
* @a: a #ClutterPoint
* @b: a #ClutterPoint
* @x_distance: (out) (allow-none): return location for the horizontal
* distance between the points
* @y_distance: (out) (allow-none): return location for the vertical
* distance between the points
*
* Computes the distance between two #ClutterPoint.
*
* Return value: the distance between the points.
*
* Since: 1.12
*/
float
clutter_point_distance (const ClutterPoint *a,
const ClutterPoint *b,
float *x_distance,
float *y_distance)
{
float x_d, y_d;
g_return_val_if_fail (a != NULL, 0.f);
g_return_val_if_fail (b != NULL, 0.f);
if (clutter_point_equals (a, b))
return 0.f;
x_d = (a->x - b->x);
y_d = (a->y - b->y);
if (x_distance != NULL)
*x_distance = fabsf (x_d);
if (y_distance != NULL)
*y_distance = fabsf (y_d);
return sqrt ((x_d * x_d) + (y_d * y_d));
}
/**
* clutter_rect_equals:
* @a: a #ClutterRect
* @b: a #ClutterRect
*
* Checks whether @a and @b are equals.
*
* This function will normalize both @a and @b before comparing
* their origin and size.
*
* Return value: %TRUE if the rectangles match in origin and size.
*
* Since: 1.12
*/
gboolean
clutter_rect_equals (ClutterRect *a,
ClutterRect *b)
{
if (a == b)
return TRUE;
if (a == NULL || b == NULL)
return FALSE;
clutter_rect_normalize_internal (a);
clutter_rect_normalize_internal (b);
return clutter_point_equals (&a->origin, &b->origin) &&
clutter_size_equals (&a->size, &b->size);
}
