gtk2/gtk/gtkgesturerotate.c
Emmanuele Bassi f28aa1ba02 Restructure the GdkEvent type hierarchy
GdkEvent has been a "I-can't-believe-this-is-not-OOP" type for ages,
using a union of sub-types. This has always been problematic when it
comes to implementing accessor functions: either you get generic API
that takes a GdkEvent and uses a massive switch() to determine which
event types have the data you're looking for; or you create namespaced
accessors, but break language bindings horribly, as boxed types cannot
have derived types.

The recent conversion of GskRenderNode (which had similar issues) to
GTypeInstance, and the fact that GdkEvent is now a completely opaque
type, provide us with the chance of moving GdkEvent to GTypeInstance,
and have sub-types for GdkEvent.

The change from boxed type to GTypeInstance is pretty small, all things
considered, but ends up cascading to a larger commit, as we still have
backends and code in GTK trying to access GdkEvent structures directly.
Additionally, the naming of the public getter functions requires
renaming all the data structures to conform to the namespace/type-name
pattern.
2020-04-16 19:54:02 +01:00

297 lines
8.6 KiB
C

/* 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"
#include "gtkintl.h"
typedef struct _GtkGestureRotatePrivate GtkGestureRotatePrivate;
enum {
ANGLE_CHANGED,
LAST_SIGNAL
};
struct _GtkGestureRotatePrivate
{
gdouble initial_angle;
gdouble accum_touchpad_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)
{
GtkGestureRotatePrivate *priv;
GdkEvent *last_event;
gdouble x1, y1, x2, y2;
GtkGesture *gesture;
gdouble dx, dy;
GList *sequences = NULL;
GdkTouchpadGesturePhase phase;
gboolean retval = FALSE;
gesture = GTK_GESTURE (rotate);
priv = gtk_gesture_rotate_get_instance_private (rotate);
if (!gtk_gesture_is_recognized (gesture))
goto out;
sequences = gtk_gesture_get_sequences (gesture);
if (!sequences)
goto out;
last_event = gtk_gesture_get_last_event (gesture, sequences->data);
phase = gdk_touchpad_event_get_gesture_phase (last_event);
if (gdk_event_get_event_type (last_event) == GDK_TOUCHPAD_PINCH &&
(phase == GDK_TOUCHPAD_GESTURE_PHASE_BEGIN ||
phase == GDK_TOUCHPAD_GESTURE_PHASE_UPDATE ||
phase == GDK_TOUCHPAD_GESTURE_PHASE_END))
{
*angle = priv->accum_touchpad_angle;
}
else
{
if (!sequences->next)
goto out;
gtk_gesture_get_point (gesture, sequences->data, &x1, &y1);
gtk_gesture_get_point (gesture, sequences->next->data, &x2, &y2);
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);
}
retval = TRUE;
out:
g_list_free (sequences);
return retval;
}
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 gboolean
gtk_gesture_rotate_filter_event (GtkEventController *controller,
GdkEvent *event)
{
/* Let 2-finger touchpad pinch events go through */
if (gdk_event_get_event_type (event) == GDK_TOUCHPAD_PINCH)
{
guint n_fingers;
n_fingers = gdk_touchpad_event_get_n_fingers (event);
if (n_fingers == 2)
return FALSE;
else
return TRUE;
}
return GTK_EVENT_CONTROLLER_CLASS (gtk_gesture_rotate_parent_class)->filter_event (controller, event);
}
static gboolean
gtk_gesture_rotate_handle_event (GtkEventController *controller,
GdkEvent *event,
double x,
double y)
{
GtkGestureRotate *rotate = GTK_GESTURE_ROTATE (controller);
GtkGestureRotatePrivate *priv;
GdkTouchpadGesturePhase phase;
double delta;
priv = gtk_gesture_rotate_get_instance_private (rotate);
if (gdk_event_get_event_type (event) == GDK_TOUCHPAD_PINCH)
{
phase = gdk_touchpad_event_get_gesture_phase (event);
delta = gdk_touchpad_event_get_pinch_angle_delta (event);
if (phase == GDK_TOUCHPAD_GESTURE_PHASE_BEGIN ||
phase == GDK_TOUCHPAD_GESTURE_PHASE_END)
priv->accum_touchpad_angle = 0;
else if (phase == GDK_TOUCHPAD_GESTURE_PHASE_UPDATE)
priv->accum_touchpad_angle += delta;
}
return GTK_EVENT_CONTROLLER_CLASS (gtk_gesture_rotate_parent_class)->handle_event (controller, event, x, y);
}
static void
gtk_gesture_rotate_class_init (GtkGestureRotateClass *klass)
{
GObjectClass *object_class = G_OBJECT_CLASS (klass);
GtkEventControllerClass *event_controller_class = GTK_EVENT_CONTROLLER_CLASS (klass);
GtkGestureClass *gesture_class = GTK_GESTURE_CLASS (klass);
object_class->constructor = gtk_gesture_rotate_constructor;
event_controller_class->filter_event = gtk_gesture_rotate_filter_event;
event_controller_class->handle_event = gtk_gesture_rotate_handle_event;
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.
*/
signals[ANGLE_CHANGED] =
g_signal_new (I_("angle-changed"),
GTK_TYPE_GESTURE_ROTATE,
G_SIGNAL_RUN_FIRST,
G_STRUCT_OFFSET (GtkGestureRotateClass, angle_changed),
NULL, NULL,
_gtk_marshal_VOID__DOUBLE_DOUBLE,
G_TYPE_NONE, 2, G_TYPE_DOUBLE, G_TYPE_DOUBLE);
g_signal_set_va_marshaller (signals[ANGLE_CHANGED],
G_TYPE_FROM_CLASS (klass),
_gtk_marshal_VOID__DOUBLE_DOUBLEv);
}
/**
* gtk_gesture_rotate_new:
*
* Returns a newly created #GtkGesture that recognizes 2-touch
* rotation gestures.
*
* Returns: a newly created #GtkGestureRotate
**/
GtkGesture *
gtk_gesture_rotate_new (void)
{
return g_object_new (GTK_TYPE_GESTURE_ROTATE,
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
**/
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;
}