clutter-drop-action.c 15.7 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
/*
 * Clutter.
 *
 * An OpenGL based 'interactive canvas' library.
 *
 * Copyright © 2011  Intel Corporation.
 *
 * 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:
 *   Emmanuele Bassi <ebassi@linux.intel.com>
 */

/**
 * SECTION:clutter-drop-action
 * @Title: ClutterDropAction
 * @short_description: An action for drop targets
 *
 * #ClutterDropAction is a #ClutterAction that allows a #ClutterActor
31 32 33
 * implementation to control what happens when an actor dragged using
 * a #ClutterDragAction crosses the target area or when a dragged actor
 * is released (or "dropped") on the target area.
34 35 36 37 38
 *
 * A trivial use of #ClutterDropAction consists in connecting to the
 * #ClutterDropAction::drop signal and handling the drop from there,
 * for instance:
 *
Emmanuele Bassi's avatar
Emmanuele Bassi committed
39
 * |[<!-- language="C" -->
40 41 42 43 44 45 46 47 48 49 50 51
 *   ClutterAction *action = clutter_drop_action ();
 *
 *   g_signal_connect (action, "drop", G_CALLBACK (on_drop), NULL);
 *   clutter_actor_add_action (an_actor, action);
 * ]|
 *
 * The #ClutterDropAction::can-drop can be used to control whether the
 * #ClutterDropAction::drop signal is going to be emitted; returning %FALSE
 * from a handler connected to the #ClutterDropAction::can-drop signal will
 * cause the #ClutterDropAction::drop signal to be skipped when the input
 * device button is released.
 *
52 53 54
 * It's important to note that #ClutterDropAction will only work with
 * actors dragged using #ClutterDragAction.
 *
Emmanuele Bassi's avatar
Emmanuele Bassi committed
55 56 57
 * See [drop-action.c](https://git.gnome.org/browse/clutter/tree/examples/drop-action.c?h=clutter-1.18)
 * for an example of how to use #ClutterDropAction.
 *
58 59 60
 * #ClutterDropAction is available since Clutter 1.8
 */

Emmanuele Bassi's avatar
Emmanuele Bassi committed
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
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "clutter-drop-action.h"

#include "clutter-actor-meta-private.h"
#include "clutter-actor-private.h"
#include "clutter-drag-action.h"
#include "clutter-main.h"
#include "clutter-marshal.h"
#include "clutter-stage-private.h"

struct _ClutterDropActionPrivate
{
  ClutterActor *actor;
  ClutterActor *stage;

  gulong mapped_id;
};

typedef struct _DropTarget {
  ClutterActor *stage;

  gulong capture_id;

  GHashTable *actions;

  ClutterDropAction *last_action;
} DropTarget;

enum
{
  CAN_DROP,
  OVER_IN,
  OVER_OUT,
  DROP,
98
  DROP_CANCEL,
Emmanuele Bassi's avatar
Emmanuele Bassi committed
99 100 101 102 103 104

  LAST_SIGNAL
};

static guint drop_signals[LAST_SIGNAL] = { 0, };

105
G_DEFINE_TYPE_WITH_PRIVATE (ClutterDropAction, clutter_drop_action, CLUTTER_TYPE_ACTION)
Emmanuele Bassi's avatar
Emmanuele Bassi committed
106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125

static void
drop_target_free (gpointer _data)
{
  DropTarget *data = _data;

  g_signal_handler_disconnect (data->stage, data->capture_id);
  g_hash_table_destroy (data->actions);
  g_free (data);
}

static gboolean
on_stage_capture (ClutterStage *stage,
                  ClutterEvent *event,
                  gpointer      user_data)
{
  DropTarget *data = user_data;
  gfloat event_x, event_y;
  ClutterActor *actor, *drag_actor;
  ClutterDropAction *drop_action;
126
  ClutterInputDevice *device;
Emmanuele Bassi's avatar
Emmanuele Bassi committed
127 128
  gboolean was_reactive;

129 130 131 132
  switch (clutter_event_type (event))
    {
    case CLUTTER_MOTION:
    case CLUTTER_BUTTON_RELEASE:
133 134 135
      if (clutter_event_type (event) == CLUTTER_MOTION &&
          !(clutter_event_get_state (event) & CLUTTER_BUTTON1_MASK))
        return CLUTTER_EVENT_PROPAGATE;
136

137 138 139
      if (clutter_event_type (event) == CLUTTER_BUTTON_RELEASE &&
          clutter_event_get_button (event) != CLUTTER_BUTTON_PRIMARY)
        return CLUTTER_EVENT_PROPAGATE;
140

141 142 143 144
      device = clutter_event_get_device (event);
      drag_actor = _clutter_stage_get_pointer_drag_actor (stage, device);
      if (drag_actor == NULL)
        return CLUTTER_EVENT_PROPAGATE;
145 146 147 148 149 150 151 152 153 154 155 156 157
      break;

    case CLUTTER_TOUCH_UPDATE:
    case CLUTTER_TOUCH_END:
      drag_actor = _clutter_stage_get_touch_drag_actor (stage,
                                                        clutter_event_get_event_sequence (event));
      if (drag_actor == NULL)
        return CLUTTER_EVENT_PROPAGATE;
      break;

    default:
      return CLUTTER_EVENT_PROPAGATE;
    }
Emmanuele Bassi's avatar
Emmanuele Bassi committed
158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224

  clutter_event_get_coords (event, &event_x, &event_y);

  /* get the actor under the cursor, excluding the dragged actor; we
   * use reactivity because it won't cause any scene invalidation
   */
  was_reactive = clutter_actor_get_reactive (drag_actor);
  clutter_actor_set_reactive (drag_actor, FALSE);

  actor = clutter_stage_get_actor_at_pos (stage, CLUTTER_PICK_REACTIVE,
                                          event_x,
                                          event_y);
  if (actor == NULL || actor == CLUTTER_ACTOR (stage))
    {
      if (data->last_action != NULL)
        {
          ClutterActorMeta *meta = CLUTTER_ACTOR_META (data->last_action);

          g_signal_emit (data->last_action, drop_signals[OVER_OUT], 0,
                         clutter_actor_meta_get_actor (meta));

          data->last_action = NULL;
        }

      goto out;
    }

  drop_action = g_hash_table_lookup (data->actions, actor);

  if (drop_action == NULL)
    {
      if (data->last_action != NULL)
        {
          ClutterActorMeta *meta = CLUTTER_ACTOR_META (data->last_action);

          g_signal_emit (data->last_action, drop_signals[OVER_OUT], 0,
                         clutter_actor_meta_get_actor (meta));

          data->last_action = NULL;
        }

      goto out;
    }
  else
    {
      if (data->last_action != drop_action)
        {
          ClutterActorMeta *meta;

          if (data->last_action != NULL)
            {
              meta = CLUTTER_ACTOR_META (data->last_action);

              g_signal_emit (data->last_action, drop_signals[OVER_OUT], 0,
                             clutter_actor_meta_get_actor (meta));
            }

          meta = CLUTTER_ACTOR_META (drop_action);

          g_signal_emit (drop_action, drop_signals[OVER_IN], 0,
                         clutter_actor_meta_get_actor (meta));
        }

      data->last_action = drop_action;
    }

out:
225 226
  if (clutter_event_type (event) == CLUTTER_BUTTON_RELEASE ||
      clutter_event_type (event) == CLUTTER_TOUCH_END)
Emmanuele Bassi's avatar
Emmanuele Bassi committed
227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243
    {
      if (data->last_action != NULL)
        {
          ClutterActorMeta *meta = CLUTTER_ACTOR_META (data->last_action);
          gboolean can_drop = FALSE;

          g_signal_emit (data->last_action, drop_signals[CAN_DROP], 0,
                         clutter_actor_meta_get_actor (meta),
                         event_x, event_y,
                         &can_drop);

          if (can_drop)
            {
              g_signal_emit (data->last_action, drop_signals[DROP], 0,
                             clutter_actor_meta_get_actor (meta),
                             event_x, event_y);
            }
244 245 246 247 248 249 250
	  else
            {
              g_signal_emit (data->last_action, drop_signals[DROP_CANCEL], 0,
                             clutter_actor_meta_get_actor (meta),
                             event_x, event_y);
            }

Emmanuele Bassi's avatar
Emmanuele Bassi committed
251 252 253 254 255 256 257 258
        }

      data->last_action = NULL;
    }

  if (drag_actor != NULL)
    clutter_actor_set_reactive (drag_actor, was_reactive);

259
  return CLUTTER_EVENT_PROPAGATE;
Emmanuele Bassi's avatar
Emmanuele Bassi committed
260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291
}

static void
drop_action_register (ClutterDropAction *self)
{
  ClutterDropActionPrivate *priv = self->priv;
  DropTarget *data;

  g_assert (priv->stage != NULL);

  data = g_object_get_data (G_OBJECT (priv->stage), "__clutter_drop_targets");
  if (data == NULL)
    {
      data = g_new0 (DropTarget, 1);

      data->stage = priv->stage;
      data->actions = g_hash_table_new (NULL, NULL);
      data->capture_id = g_signal_connect (priv->stage, "captured-event",
                                           G_CALLBACK (on_stage_capture),
                                           data);
      g_object_set_data_full (G_OBJECT (priv->stage), "__clutter_drop_targets",
                              data,
                              drop_target_free);
    }

  g_hash_table_replace (data->actions, priv->actor, self);
}

static void
drop_action_unregister (ClutterDropAction *self)
{
  ClutterDropActionPrivate *priv = self->priv;
292 293 294 295
  DropTarget *data = NULL;

  if (priv->stage != NULL)
    data = g_object_get_data (G_OBJECT (priv->stage), "__clutter_drop_targets");
Emmanuele Bassi's avatar
Emmanuele Bassi committed
296 297 298 299 300 301 302 303 304 305 306 307 308 309

  if (data == NULL)
    return;

  g_hash_table_remove (data->actions, priv->actor);
  if (g_hash_table_size (data->actions) == 0)
    g_object_set_data (G_OBJECT (data->stage), "__clutter_drop_targets", NULL);
}

static void
on_actor_mapped (ClutterActor      *actor,
                 GParamSpec        *pspec,
                 ClutterDropAction *self)
{
310
  if (clutter_actor_is_mapped (actor))
Emmanuele Bassi's avatar
Emmanuele Bassi committed
311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386
    {
      if (self->priv->stage == NULL)
        self->priv->stage = clutter_actor_get_stage (actor);

      drop_action_register (self);
    }
  else
    drop_action_unregister (self);
}

static void
clutter_drop_action_set_actor (ClutterActorMeta *meta,
                               ClutterActor     *actor)
{
  ClutterDropActionPrivate *priv = CLUTTER_DROP_ACTION (meta)->priv;

  if (priv->actor != NULL)
    {
      drop_action_unregister (CLUTTER_DROP_ACTION (meta));

      if (priv->mapped_id != 0)
        g_signal_handler_disconnect (priv->actor, priv->mapped_id);

      priv->stage = NULL;
      priv->actor = NULL;
      priv->mapped_id = 0;
    }

  priv->actor = actor;

  if (priv->actor != NULL)
    {
      priv->stage = clutter_actor_get_stage (actor);
      priv->mapped_id = g_signal_connect (actor, "notify::mapped",
                                          G_CALLBACK (on_actor_mapped),
                                          meta);

      if (priv->stage != NULL)
        drop_action_register (CLUTTER_DROP_ACTION (meta));
    }

  CLUTTER_ACTOR_META_CLASS (clutter_drop_action_parent_class)->set_actor (meta, actor);
}

static gboolean
signal_accumulator (GSignalInvocationHint *ihint,
                    GValue                *return_accu,
                    const GValue          *handler_return,
                    gpointer               user_data)
{
  gboolean continue_emission;

  continue_emission = g_value_get_boolean (handler_return);
  g_value_set_boolean (return_accu, continue_emission);

  return continue_emission;
}

static gboolean
clutter_drop_action_real_can_drop (ClutterDropAction *action,
                                   ClutterActor      *actor,
                                   gfloat             event_x,
                                   gfloat             event_y)
{
  return TRUE;
}

static void
clutter_drop_action_class_init (ClutterDropActionClass *klass)
{
  ClutterActorMetaClass *meta_class = CLUTTER_ACTOR_META_CLASS (klass);

  meta_class->set_actor = clutter_drop_action_set_actor;

  klass->can_drop = clutter_drop_action_real_can_drop;

387 388 389 390
  /**
   * ClutterDropAction::can-drop:
   * @action: the #ClutterDropAction that emitted the signal
   * @actor: the #ClutterActor attached to the @action
391 392
   * @event_x: the X coordinate (in stage space) of the drop event
   * @event_y: the Y coordinate (in stage space) of the drop event
393 394 395 396 397 398 399 400 401 402 403 404 405
   *
   * The ::can-drop signal is emitted when the dragged actor is dropped
   * on @actor. The return value of the ::can-drop signal will determine
   * whether or not the #ClutterDropAction::drop signal is going to be
   * emitted on @action.
   *
   * The default implementation of #ClutterDropAction returns %TRUE for
   * this signal.
   *
   * Return value: %TRUE if the drop is accepted, and %FALSE otherwise
   *
   * Since: 1.8
   */
Emmanuele Bassi's avatar
Emmanuele Bassi committed
406 407 408 409 410 411 412 413 414 415 416 417
  drop_signals[CAN_DROP] =
    g_signal_new (I_("can-drop"),
                  G_TYPE_FROM_CLASS (klass),
                  G_SIGNAL_RUN_LAST,
                  G_STRUCT_OFFSET (ClutterDropActionClass, can_drop),
                  signal_accumulator, NULL,
                  _clutter_marshal_BOOLEAN__OBJECT_FLOAT_FLOAT,
                  G_TYPE_BOOLEAN, 3,
                  CLUTTER_TYPE_ACTOR,
                  G_TYPE_FLOAT,
                  G_TYPE_FLOAT);

418 419 420 421 422 423 424 425 426 427
  /**
   * ClutterDropAction::over-in:
   * @action: the #ClutterDropAction that emitted the signal
   * @actor: the #ClutterActor attached to the @action
   *
   * The ::over-in signal is emitted when the dragged actor crosses
   * into @actor.
   *
   * Since: 1.8
   */
Emmanuele Bassi's avatar
Emmanuele Bassi committed
428 429 430 431 432 433 434 435 436 437
  drop_signals[OVER_IN] =
    g_signal_new (I_("over-in"),
                  G_TYPE_FROM_CLASS (klass),
                  G_SIGNAL_RUN_LAST,
                  G_STRUCT_OFFSET (ClutterDropActionClass, over_in),
                  NULL, NULL,
                  _clutter_marshal_VOID__OBJECT,
                  G_TYPE_NONE, 1,
                  CLUTTER_TYPE_ACTOR);

438 439 440 441 442 443 444 445 446 447
  /**
   * ClutterDropAction::over-out:
   * @action: the #ClutterDropAction that emitted the signal
   * @actor: the #ClutterActor attached to the @action
   *
   * The ::over-out signal is emitted when the dragged actor crosses
   * outside @actor.
   *
   * Since: 1.8
   */
Emmanuele Bassi's avatar
Emmanuele Bassi committed
448 449 450 451 452 453 454 455 456 457
  drop_signals[OVER_OUT] =
    g_signal_new (I_("over-out"),
                  G_TYPE_FROM_CLASS (klass),
                  G_SIGNAL_RUN_LAST,
                  G_STRUCT_OFFSET (ClutterDropActionClass, over_out),
                  NULL, NULL,
                  _clutter_marshal_VOID__OBJECT,
                  G_TYPE_NONE, 1,
                  CLUTTER_TYPE_ACTOR);

458 459 460 461
  /**
   * ClutterDropAction::drop:
   * @action: the #ClutterDropAction that emitted the signal
   * @actor: the #ClutterActor attached to the @action
462 463
   * @event_x: the X coordinate (in stage space) of the drop event
   * @event_y: the Y coordinate (in stage space) of the drop event
464 465 466 467 468 469 470
   *
   * The ::drop signal is emitted when the dragged actor is dropped
   * on @actor. This signal is only emitted if at least an handler of
   * #ClutterDropAction::can-drop returns %TRUE.
   *
   * Since: 1.8
   */
Emmanuele Bassi's avatar
Emmanuele Bassi committed
471 472 473 474 475 476 477 478 479 480 481
  drop_signals[DROP] =
    g_signal_new (I_("drop"),
                  G_TYPE_FROM_CLASS (klass),
                  G_SIGNAL_RUN_LAST,
                  G_STRUCT_OFFSET (ClutterDropActionClass, drop),
                  NULL, NULL,
                  _clutter_marshal_VOID__OBJECT_FLOAT_FLOAT,
                  G_TYPE_NONE, 3,
                  CLUTTER_TYPE_ACTOR,
                  G_TYPE_FLOAT,
                  G_TYPE_FLOAT);
482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509


  /**
   * ClutterDropAction::drop-cancel:
   * @action: the #ClutterDropAction that emitted the signal
   * @actor: the #ClutterActor attached to the @action
   * @event_x: the X coordinate (in stage space) of the drop event
   * @event_y: the Y coordinate (in stage space) of the drop event
   *
   * The ::drop-cancel signal is emitted when the drop is refused
   * by an emission of the #ClutterDropAction::can-drop signal.
   *
   * After the ::drop-cancel signal is fired the active drag is
   * terminated.
   *
   * Since: 1.12
   */
  drop_signals[DROP_CANCEL] =
    g_signal_new (I_("drop-cancel"),
                  G_TYPE_FROM_CLASS (klass),
                  G_SIGNAL_RUN_LAST,
                  G_STRUCT_OFFSET (ClutterDropActionClass, drop),
                  NULL, NULL,
                  _clutter_marshal_VOID__OBJECT_FLOAT_FLOAT,
                  G_TYPE_NONE, 3,
                  CLUTTER_TYPE_ACTOR,
                  G_TYPE_FLOAT,
                  G_TYPE_FLOAT);
Emmanuele Bassi's avatar
Emmanuele Bassi committed
510 511 512 513 514
}

static void
clutter_drop_action_init (ClutterDropAction *self)
{
515
  self->priv = clutter_drop_action_get_instance_private (self);
Emmanuele Bassi's avatar
Emmanuele Bassi committed
516 517
}

518 519 520 521 522 523 524 525 526 527 528
/**
 * clutter_drop_action_new:
 *
 * Creates a new #ClutterDropAction.
 *
 * Use clutter_actor_add_action() to add the action to a #ClutterActor.
 *
 * Return value: the newly created #ClutterDropAction
 *
 * Since: 1.8
 */
Emmanuele Bassi's avatar
Emmanuele Bassi committed
529 530 531 532 533
ClutterAction *
clutter_drop_action_new (void)
{
  return g_object_new (CLUTTER_TYPE_DROP_ACTION, NULL);
}