gtkgesturerotate.c 5.96 KB
Newer Older
Carlos Garnacho's avatar
Carlos Garnacho committed
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
/* 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>
 */
20
21
22
23
24
25
26
27
28

/**
 * 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
Carlos Garnacho's avatar
Carlos Garnacho committed
29
 * changes, the #GtkGestureRotate::angle-changed signal is emitted.
30
31
 */

Carlos Garnacho's avatar
Carlos Garnacho committed
32
33
#include "config.h"
#include <math.h>
34
35
#include "gtkgesturerotate.h"
#include "gtkgesturerotateprivate.h"
Carlos Garnacho's avatar
Carlos Garnacho committed
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
#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;
113
  gdouble angle, delta;
Carlos Garnacho's avatar
Carlos Garnacho committed
114
115
116
117
118

  if (!_gtk_gesture_rotate_get_angle (gesture, &angle))
    return FALSE;

  priv = gtk_gesture_rotate_get_instance_private (gesture);
119
  delta = angle - priv->initial_angle;
Carlos Garnacho's avatar
Carlos Garnacho committed
120

121
122
123
124
  if (delta < 0)
    delta += 2 * G_PI;

  g_signal_emit (gesture, signals[ANGLE_CHANGED], 0, angle, delta);
Carlos Garnacho's avatar
Carlos Garnacho committed
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
  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
161
162
163
164
165
166
   * @angle_delta: Difference with the starting angle, in radians
   *
   * This signal is emitted when the angle between both tracked points
   * changes.
   *
   * Since: 3.14
Carlos Garnacho's avatar
Carlos Garnacho committed
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
   */
  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)
{
  return g_object_new (GTK_TYPE_GESTURE_ROTATE,
                       "widget", widget,
                       NULL);
}

/**
 * gtk_gesture_rotate_get_angle_delta:
 * @gesture: a #GtkGestureRotate
 *
200
 * If @gesture is active, this function returns the angle difference
Matthias Clasen's avatar
Matthias Clasen committed
201
202
 * in radians since the gesture was first recognized. If @gesture is
 * not active, 0 is returned.
Carlos Garnacho's avatar
Carlos Garnacho committed
203
 *
204
 * Returns: the angle delta in radians
Carlos Garnacho's avatar
Carlos Garnacho committed
205
206
207
 *
 * Since: 3.14
 **/
208
209
gdouble
gtk_gesture_rotate_get_angle_delta (GtkGestureRotate *gesture)
Carlos Garnacho's avatar
Carlos Garnacho committed
210
211
212
213
{
  GtkGestureRotatePrivate *priv;
  gdouble angle;

Matthias Clasen's avatar
Matthias Clasen committed
214
  g_return_val_if_fail (GTK_IS_GESTURE_ROTATE (gesture), 0.0);
Carlos Garnacho's avatar
Carlos Garnacho committed
215
216

  if (!_gtk_gesture_rotate_get_angle (gesture, &angle))
Matthias Clasen's avatar
Matthias Clasen committed
217
    return 0.0;
Carlos Garnacho's avatar
Carlos Garnacho committed
218
219
220

  priv = gtk_gesture_rotate_get_instance_private (gesture);

221
  return angle - priv->initial_angle;
Carlos Garnacho's avatar
Carlos Garnacho committed
222
}