gtk2/gtk/gtkgesturedrag.c
2018-04-26 17:59:42 +02:00

285 lines
8.4 KiB
C

/* GTK - The GIMP Toolkit
* 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:gtkgesturedrag
* @Short_description: Drag gesture
* @Title: GtkGestureDrag
* @See_also: #GtkGestureSwipe
*
* #GtkGestureDrag is a #GtkGesture implementation that recognizes drag
* operations. The drag operation itself can be tracked throught the
* #GtkGestureDrag::drag-begin, #GtkGestureDrag::drag-update and
* #GtkGestureDrag::drag-end signals, or the relevant coordinates be
* extracted through gtk_gesture_drag_get_offset() and
* gtk_gesture_drag_get_start_point().
*/
#include "config.h"
#include "gtkgesturedrag.h"
#include "gtkgesturedragprivate.h"
#include "gtkintl.h"
typedef struct _GtkGestureDragPrivate GtkGestureDragPrivate;
typedef struct _EventData EventData;
struct _GtkGestureDragPrivate
{
gdouble start_x;
gdouble start_y;
gdouble last_x;
gdouble last_y;
};
enum {
DRAG_BEGIN,
DRAG_UPDATE,
DRAG_END,
N_SIGNALS
};
static guint signals[N_SIGNALS] = { 0 };
G_DEFINE_TYPE_WITH_PRIVATE (GtkGestureDrag, gtk_gesture_drag, GTK_TYPE_GESTURE_SINGLE)
static gboolean
gtk_gesture_drag_filter_event (GtkEventController *controller,
const GdkEvent *event)
{
/* Let touchpad swipe events go through, only if they match n-points */
if (gdk_event_get_event_type (event) == GDK_TOUCHPAD_SWIPE)
{
guint n_points;
guint n_fingers;
g_object_get (G_OBJECT (controller), "n-points", &n_points, NULL);
gdk_event_get_touchpad_gesture_n_fingers (event, &n_fingers);
if (n_fingers == n_points)
return FALSE;
else
return TRUE;
}
return GTK_EVENT_CONTROLLER_CLASS (gtk_gesture_drag_parent_class)->filter_event (controller, event);
}
static void
gtk_gesture_drag_begin (GtkGesture *gesture,
GdkEventSequence *sequence)
{
GtkGestureDragPrivate *priv;
GdkEventSequence *current;
current = gtk_gesture_single_get_current_sequence (GTK_GESTURE_SINGLE (gesture));
priv = gtk_gesture_drag_get_instance_private (GTK_GESTURE_DRAG (gesture));
gtk_gesture_get_point (gesture, current, &priv->start_x, &priv->start_y);
priv->last_x = priv->start_x;
priv->last_y = priv->start_y;
g_signal_emit (gesture, signals[DRAG_BEGIN], 0, priv->start_x, priv->start_y);
}
static void
gtk_gesture_drag_update (GtkGesture *gesture,
GdkEventSequence *sequence)
{
GtkGestureDragPrivate *priv;
gdouble x, y;
priv = gtk_gesture_drag_get_instance_private (GTK_GESTURE_DRAG (gesture));
gtk_gesture_get_point (gesture, sequence, &priv->last_x, &priv->last_y);
x = priv->last_x - priv->start_x;
y = priv->last_y - priv->start_y;
g_signal_emit (gesture, signals[DRAG_UPDATE], 0, x, y);
}
static void
gtk_gesture_drag_end (GtkGesture *gesture,
GdkEventSequence *sequence)
{
GtkGestureDragPrivate *priv;
GdkEventSequence *current;
gdouble x, y;
current = gtk_gesture_single_get_current_sequence (GTK_GESTURE_SINGLE (gesture));
priv = gtk_gesture_drag_get_instance_private (GTK_GESTURE_DRAG (gesture));
gtk_gesture_get_point (gesture, current, &priv->last_x, &priv->last_y);
x = priv->last_x - priv->start_x;
y = priv->last_y - priv->start_y;
g_signal_emit (gesture, signals[DRAG_END], 0, x, y);
}
static void
gtk_gesture_drag_class_init (GtkGestureDragClass *klass)
{
GtkGestureClass *gesture_class = GTK_GESTURE_CLASS (klass);
GtkEventControllerClass *event_controller_class = GTK_EVENT_CONTROLLER_CLASS (klass);
event_controller_class->filter_event = gtk_gesture_drag_filter_event;
gesture_class->begin = gtk_gesture_drag_begin;
gesture_class->update = gtk_gesture_drag_update;
gesture_class->end = gtk_gesture_drag_end;
/**
* GtkGestureDrag::drag-begin:
* @gesture: the object which received the signal
* @start_x: X coordinate, relative to the widget allocation
* @start_y: Y coordinate, relative to the widget allocation
*
* This signal is emitted whenever dragging starts.
*/
signals[DRAG_BEGIN] =
g_signal_new (I_("drag-begin"),
G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GtkGestureDragClass, drag_begin),
NULL, NULL, NULL,
G_TYPE_NONE, 2, G_TYPE_DOUBLE, G_TYPE_DOUBLE);
/**
* GtkGestureDrag::drag-update:
* @gesture: the object which received the signal
* @offset_x: X offset, relative to the start point
* @offset_y: Y offset, relative to the start point
*
* This signal is emitted whenever the dragging point moves.
*/
signals[DRAG_UPDATE] =
g_signal_new (I_("drag-update"),
G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GtkGestureDragClass, drag_update),
NULL, NULL, NULL,
G_TYPE_NONE, 2, G_TYPE_DOUBLE, G_TYPE_DOUBLE);
/**
* GtkGestureDrag::drag-end:
* @gesture: the object which received the signal
* @offset_x: X offset, relative to the start point
* @offset_y: Y offset, relative to the start point
*
* This signal is emitted whenever the dragging is finished.
*/
signals[DRAG_END] =
g_signal_new (I_("drag-end"),
G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GtkGestureDragClass, drag_end),
NULL, NULL, NULL,
G_TYPE_NONE, 2, G_TYPE_DOUBLE, G_TYPE_DOUBLE);
}
static void
gtk_gesture_drag_init (GtkGestureDrag *gesture)
{
}
/**
* gtk_gesture_drag_new:
*
* Returns a newly created #GtkGesture that recognizes drags.
*
* Returns: a newly created #GtkGestureDrag
**/
GtkGesture *
gtk_gesture_drag_new (void)
{
return g_object_new (GTK_TYPE_GESTURE_DRAG,
NULL);
}
/**
* gtk_gesture_drag_get_start_point:
* @gesture: a #GtkGesture
* @x: (out) (nullable): X coordinate for the drag start point
* @y: (out) (nullable): Y coordinate for the drag start point
*
* If the @gesture is active, this function returns %TRUE
* and fills in @x and @y with the drag start coordinates,
* in window-relative coordinates.
*
* Returns: %TRUE if the gesture is active
**/
gboolean
gtk_gesture_drag_get_start_point (GtkGestureDrag *gesture,
gdouble *x,
gdouble *y)
{
GtkGestureDragPrivate *priv;
GdkEventSequence *sequence;
g_return_val_if_fail (GTK_IS_GESTURE_DRAG (gesture), FALSE);
sequence = gtk_gesture_single_get_current_sequence (GTK_GESTURE_SINGLE (gesture));
if (!gtk_gesture_handles_sequence (GTK_GESTURE (gesture), sequence))
return FALSE;
priv = gtk_gesture_drag_get_instance_private (gesture);
if (x)
*x = priv->start_x;
if (y)
*y = priv->start_y;
return TRUE;
}
/**
* gtk_gesture_drag_get_offset:
* @gesture: a #GtkGesture
* @x: (out) (nullable): X offset for the current point
* @y: (out) (nullable): Y offset for the current point
*
* If the @gesture is active, this function returns %TRUE and
* fills in @x and @y with the coordinates of the current point,
* as an offset to the starting drag point.
*
* Returns: %TRUE if the gesture is active
**/
gboolean
gtk_gesture_drag_get_offset (GtkGestureDrag *gesture,
gdouble *x,
gdouble *y)
{
GtkGestureDragPrivate *priv;
GdkEventSequence *sequence;
g_return_val_if_fail (GTK_IS_GESTURE_DRAG (gesture), FALSE);
sequence = gtk_gesture_single_get_current_sequence (GTK_GESTURE_SINGLE (gesture));
if (!gtk_gesture_handles_sequence (GTK_GESTURE (gesture), sequence))
return FALSE;
priv = gtk_gesture_drag_get_instance_private (gesture);
if (x)
*x = priv->last_x - priv->start_x;
if (y)
*y = priv->last_y - priv->start_y;
return TRUE;
}