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/* GTK - The GIMP Toolkit
* Copyright (C) 2012, One Laptop Per Child.
* Copyright (C) 2014, Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*
* Author(s): Carlos Garnacho <carlosg@gnome.org>
*/
/**
* SECTION:gtkgesturerotate
* @Short_description: Rotate gesture
* @Title: GtkGestureRotate
* @See_also: #GtkGestureZoom
*
* #GtkGestureRotate is a #GtkGesture implementation able to recognize
* 2-finger rotations, whenever the angle between both handled sequences
* changes, the #GtkGestureRotate::angle-changed signal is emitted.
*/
#include "config.h"
#include <math.h>
#include "gtkgesturerotate.h"
#include "gtkgesturerotateprivate.h"
#include "gtkmarshalers.h"
typedef struct _GtkGestureRotatePrivate GtkGestureRotatePrivate;
enum {
ANGLE_CHANGED,
LAST_SIGNAL
};
struct _GtkGestureRotatePrivate
{
gdouble initial_angle;
};
static guint signals[LAST_SIGNAL] = { 0 };
G_DEFINE_TYPE_WITH_PRIVATE (GtkGestureRotate, gtk_gesture_rotate, GTK_TYPE_GESTURE)
static void
gtk_gesture_rotate_init (GtkGestureRotate *gesture)
{
}
static GObject *
gtk_gesture_rotate_constructor (GType type,
guint n_construct_properties,
GObjectConstructParam *construct_properties)
{
GObject *object;
object = G_OBJECT_CLASS (gtk_gesture_rotate_parent_class)->constructor (type,
n_construct_properties,
construct_properties);
g_object_set (object, "n-points", 2, NULL);
return object;
}
static gboolean
_gtk_gesture_rotate_get_angle (GtkGestureRotate *rotate,
gdouble *angle)
{
gdouble x1, y1, x2, y2;
GtkGesture *gesture;
gdouble dx, dy;
GList *sequences;
gesture = GTK_GESTURE (rotate);
if (!gtk_gesture_is_recognized (gesture))
return FALSE;
sequences = gtk_gesture_get_sequences (gesture);
g_assert (sequences && sequences->next);
gtk_gesture_get_point (gesture, sequences->data, &x1, &y1);
gtk_gesture_get_point (gesture, sequences->next->data, &x2, &y2);
g_list_free (sequences);
dx = x1 - x2;
dy = y1 - y2;
*angle = atan2 (dx, dy);
/* Invert angle */
*angle = (2 * G_PI) - *angle;
/* And constraint it to 0°-360° */
*angle = fmod (*angle, 2 * G_PI);
return TRUE;
}
static gboolean
_gtk_gesture_rotate_check_emit (GtkGestureRotate *gesture)
{
GtkGestureRotatePrivate *priv;
gdouble angle, delta;
if (!_gtk_gesture_rotate_get_angle (gesture, &angle))
return FALSE;
priv = gtk_gesture_rotate_get_instance_private (gesture);
delta = angle - priv->initial_angle;
if (delta < 0)
delta += 2 * G_PI;
g_signal_emit (gesture, signals[ANGLE_CHANGED], 0, angle, delta);
return TRUE;
}
static void
gtk_gesture_rotate_begin (GtkGesture *gesture,
GdkEventSequence *sequence)
{
GtkGestureRotate *rotate = GTK_GESTURE_ROTATE (gesture);
GtkGestureRotatePrivate *priv;
priv = gtk_gesture_rotate_get_instance_private (rotate);
_gtk_gesture_rotate_get_angle (rotate, &priv->initial_angle);
}
static void
gtk_gesture_rotate_update (GtkGesture *gesture,
GdkEventSequence *sequence)
{
_gtk_gesture_rotate_check_emit (GTK_GESTURE_ROTATE (gesture));
}
static void
gtk_gesture_rotate_class_init (GtkGestureRotateClass *klass)
{
GObjectClass *object_class = G_OBJECT_CLASS (klass);
GtkGestureClass *gesture_class = GTK_GESTURE_CLASS (klass);
object_class->constructor = gtk_gesture_rotate_constructor;
gesture_class->begin = gtk_gesture_rotate_begin;
gesture_class->update = gtk_gesture_rotate_update;
/**
* GtkGestureRotate::angle-changed:
* @gesture: the object on which the signal is emitted
* @angle: Current angle in radians
* @angle_delta: Difference with the starting angle, in radians
*
* This signal is emitted when the angle between both tracked points
* changes.
*
* Since: 3.14
*/
signals[ANGLE_CHANGED] =
g_signal_new ("angle-changed",
GTK_TYPE_GESTURE_ROTATE,
G_SIGNAL_RUN_FIRST,
G_STRUCT_OFFSET (GtkGestureRotateClass, angle_changed),
NULL, NULL, NULL,
G_TYPE_NONE, 2, G_TYPE_DOUBLE, G_TYPE_DOUBLE);
}
/**
* gtk_gesture_rotate_new:
* @widget: a #GtkWidget
*
* Returns a newly created #GtkGesture that recognizes 2-touch
* rotation gestures.
*
* Returns: a newly created #GtkGestureRotate
*
* Since: 3.14
**/
GtkGesture *
gtk_gesture_rotate_new (GtkWidget *widget)
{
g_return_val_if_fail (GTK_IS_WIDGET (widget), NULL);
return g_object_new (GTK_TYPE_GESTURE_ROTATE,
"widget", widget,
NULL);
}
/**
* gtk_gesture_rotate_get_angle_delta:
* @gesture: a #GtkGestureRotate
*
* If @gesture is active, this function returns the angle difference
* in radians since the gesture was first recognized. If @gesture is
* not active, 0 is returned.
*
* Returns: the angle delta in radians
*
* Since: 3.14
**/
gdouble
gtk_gesture_rotate_get_angle_delta (GtkGestureRotate *gesture)
{
GtkGestureRotatePrivate *priv;
gdouble angle;
g_return_val_if_fail (GTK_IS_GESTURE_ROTATE (gesture), 0.0);
if (!_gtk_gesture_rotate_get_angle (gesture, &angle))
return 0.0;
priv = gtk_gesture_rotate_get_instance_private (gesture);
return angle - priv->initial_angle;
}
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