Commit 9db3c2d8 authored by Carlos Garnacho's avatar Carlos Garnacho

Add GtkGestureZoom

This gesture interprets and reports relative scale differences when fed
with events from two different GdkEventSequences.
parent 2495b518
......@@ -284,6 +284,7 @@ gtk_public_h_sources = \
gtkgesturelongpress.h \
gtkgesturerotate.h \
gtkgestureswipe.h \
gtkgesturezoom.h \
gtkgrid.h \
gtkheaderbar.h \
gtkicontheme.h \
......@@ -780,6 +781,7 @@ gtk_base_c_sources = \
gtkgesturelongpress.c \
gtkgesturerotate.c \
gtkgestureswipe.c \
gtkgesturezoom.c \
gtkgrid.c \
gtkheaderbar.c \
gtkhsla.c \
......
......@@ -110,6 +110,7 @@
#include <gtk/gtkgesturelongpress.h>
#include <gtk/gtkgesturerotate.h>
#include <gtk/gtkgestureswipe.h>
#include <gtk/gtkgesturezoom.h>
#include <gtk/gtkgrid.h>
#include <gtk/gtkheaderbar.h>
#include <gtk/gtkicontheme.h>
......
/* 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>
*/
#include "config.h"
#include <math.h>
#include <gtk/gtkgesturezoom.h>
typedef struct _GtkGestureZoomPrivate GtkGestureZoomPrivate;
enum {
SCALE_CHANGED,
LAST_SIGNAL
};
struct _GtkGestureZoomPrivate
{
gdouble initial_distance;
};
static guint signals[LAST_SIGNAL] = { 0 };
G_DEFINE_TYPE_WITH_PRIVATE (GtkGestureZoom, gtk_gesture_zoom, GTK_TYPE_GESTURE)
static void
gtk_gesture_zoom_init (GtkGestureZoom *gesture)
{
}
static GObject *
gtk_gesture_zoom_constructor (GType type,
guint n_construct_properties,
GObjectConstructParam *construct_properties)
{
GObject *object;
object = G_OBJECT_CLASS (gtk_gesture_zoom_parent_class)->constructor (type,
n_construct_properties,
construct_properties);
g_object_set (object, "n-points", 2, NULL);
return object;
}
static gboolean
_gtk_gesture_zoom_get_distance (GtkGestureZoom *zoom,
gdouble *distance)
{
gdouble x1, y1, x2, y2;
GtkGesture *gesture;
GList *sequences;
gdouble dx, dy;
gesture = GTK_GESTURE (zoom);
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;;
*distance = sqrt ((dx * dx) + (dy * dy));
return TRUE;
}
static gboolean
_gtk_gesture_zoom_check_emit (GtkGestureZoom *gesture)
{
GtkGestureZoomPrivate *priv;
gdouble distance, zoom;
if (!_gtk_gesture_zoom_get_distance (gesture, &distance))
return FALSE;
priv = gtk_gesture_zoom_get_instance_private (gesture);
if (distance == 0 || priv->initial_distance == 0)
return FALSE;
zoom = distance / priv->initial_distance;
g_signal_emit (gesture, signals[SCALE_CHANGED], 0, zoom);
return TRUE;
}
static void
gtk_gesture_zoom_begin (GtkGesture *gesture,
GdkEventSequence *sequence)
{
GtkGestureZoom *zoom = GTK_GESTURE_ZOOM (gesture);
GtkGestureZoomPrivate *priv;
priv = gtk_gesture_zoom_get_instance_private (zoom);
_gtk_gesture_zoom_get_distance (zoom, &priv->initial_distance);
}
static void
gtk_gesture_zoom_update (GtkGesture *gesture,
GdkEventSequence *sequence)
{
_gtk_gesture_zoom_check_emit (GTK_GESTURE_ZOOM (gesture));
}
static void
gtk_gesture_zoom_class_init (GtkGestureZoomClass *klass)
{
GObjectClass *object_class = G_OBJECT_CLASS (klass);
GtkGestureClass *gesture_class = GTK_GESTURE_CLASS (klass);
object_class->constructor = gtk_gesture_zoom_constructor;
gesture_class->begin = gtk_gesture_zoom_begin;
gesture_class->update = gtk_gesture_zoom_update;
/**
* GtkGestureZoom::scale-changed:
* @controller: the object on which the signal is emitted
* @scale: Scale delta, taking the initial state as 1:1
*/
signals[SCALE_CHANGED] =
g_signal_new ("scale-changed",
GTK_TYPE_GESTURE_ZOOM,
G_SIGNAL_RUN_FIRST,
G_STRUCT_OFFSET (GtkGestureZoomClass, scale_changed),
NULL, NULL, NULL,
G_TYPE_NONE, 1, G_TYPE_DOUBLE);
}
/**
* gtk_gesture_zoom_new:
* @widget: a #GtkWidget
*
* Returns a newly created #GtkGesture that recognizes zoom
* in/out gestures (usually known as pinch/zoom)
*
* Returns: a newly created #GtkGestureZoom
*
* Since: 3.14
**/
GtkGesture *
gtk_gesture_zoom_new (GtkWidget *widget)
{
return g_object_new (GTK_TYPE_GESTURE_ZOOM,
"widget", widget,
NULL);
}
/**
* gtk_gesture_zoom_get_scale_delta:
* @gesture: a #GtkGestureZoom
* @scale: (out) (transfer none): zoom delta
*
* If @controller is active, this function returns %TRUE and fills
* in @scale with the zooming difference since the gesture was
* recognized (hence the starting point is considered 1:1).
*
* Returns: %TRUE if @controller is recognizing a zoom gesture
*
* Since: 3.14
**/
gboolean
gtk_gesture_zoom_get_scale_delta (GtkGestureZoom *gesture,
gdouble *scale)
{
GtkGestureZoomPrivate *priv;
gdouble distance;
g_return_val_if_fail (GTK_IS_GESTURE_ZOOM (gesture), FALSE);
if (!_gtk_gesture_zoom_get_distance (gesture, &distance))
return FALSE;
priv = gtk_gesture_zoom_get_instance_private (gesture);
if (scale)
*scale = distance / priv->initial_distance;
return TRUE;
}
/* 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>
*/
#ifndef __GTK_GESTURE_ZOOM_H__
#define __GTK_GESTURE_ZOOM_H__
#if !defined (__GTK_H_INSIDE__) && !defined (GTK_COMPILATION)
#error "Only <gtk/gtk.h> can be included directly."
#endif
#include <gtk/gtkgesture.h>
#include <gtk/gtk.h>
G_BEGIN_DECLS
#define GTK_TYPE_GESTURE_ZOOM (gtk_gesture_zoom_get_type ())
#define GTK_GESTURE_ZOOM(o) (G_TYPE_CHECK_INSTANCE_CAST ((o), GTK_TYPE_GESTURE_ZOOM, GtkGestureZoom))
#define GTK_GESTURE_ZOOM_CLASS(k) (G_TYPE_CHECK_CLASS_CAST ((k), GTK_TYPE_GESTURE_ZOOM, GtkGestureZoomClass))
#define GTK_IS_GESTURE_ZOOM(o) (G_TYPE_CHECK_INSTANCE_TYPE ((o), GTK_TYPE_GESTURE_ZOOM))
#define GTK_IS_GESTURE_ZOOM_CLASS(k) (G_TYPE_CHECK_CLASS_TYPE ((k), GTK_TYPE_GESTURE_ZOOM))
#define GTK_GESTURE_ZOOM_GET_CLASS(o) (G_TYPE_INSTANCE_GET_CLASS ((o), GTK_TYPE_GESTURE_ZOOM, GtkGestureZoomClass))
typedef struct _GtkGestureZoom GtkGestureZoom;
typedef struct _GtkGestureZoomClass GtkGestureZoomClass;
struct _GtkGestureZoom
{
GtkGesture parent_instance;
};
struct _GtkGestureZoomClass
{
GtkGestureClass parent_class;
void (* scale_changed) (GtkGestureZoom *gesture,
gdouble scale);
/*< private >*/
gpointer padding[10];
};
GDK_AVAILABLE_IN_3_14
GType gtk_gesture_zoom_get_type (void) G_GNUC_CONST;
GDK_AVAILABLE_IN_3_14
GtkGesture * gtk_gesture_zoom_new (GtkWidget *widget);
GDK_AVAILABLE_IN_3_14
gboolean gtk_gesture_zoom_get_scale_delta (GtkGestureZoom *gesture,
gdouble *scale);
G_END_DECLS
#endif /* __GTK_GESTURE_ZOOM_H__ */
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