clients/dnd.c

   1 /*
   2  * Copyright © 2010 Kristian Høgsberg
   3  *
   4  * Permission to use, copy, modify, distribute, and sell this software and its
   5  * documentation for any purpose is hereby granted without fee, provided that
   6  * the above copyright notice appear in all copies and that both that copyright
   7  * notice and this permission notice appear in supporting documentation, and
   8  * that the name of the copyright holders not be used in advertising or
   9  * publicity pertaining to distribution of the software without specific,
  10  * written prior permission.  The copyright holders make no representations
  11  * about the suitability of this software for any purpose.  It is provided "as
  12  * is" without express or implied warranty.
  13  *
  14  * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
  15  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
  16  * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
  17  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
  18  * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
  19  * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
  20  * OF THIS SOFTWARE.
  21  */
  22
  23 #include <stdint.h>
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <fcntl.h>
  28 #include <unistd.h>
  29 #include <math.h>
  30 #include <sys/time.h>
  31 #include <cairo.h>
  32 #include <glib.h>
  33 #include <gdk-pixbuf/gdk-pixbuf.h>
  34
  35 #include "wayland-client.h"
  36 #include "wayland-glib.h"
  37
  38 #include "window.h"
  39
  40 static const char socket_name[] = "\0wayland";
  41
  42 struct dnd {
  43         struct window *window;
  44         struct display *display;
  45         uint32_t key;
  46         struct item *items[16];
  47 };
  48
  49 struct dnd_drag {
  50         cairo_surface_t *translucent;
  51         cairo_surface_t *opaque;
  52         int hotspot_x, hotspot_y;
  53         struct dnd *dnd;
  54         struct input *input;
  55         uint32_t time;
  56         struct item *item;
  57         int x_offset, y_offset;
  58         const char *mime_type;
  59 };
  60
  61 struct dnd_offer {
  62         int refcount;
  63         struct dnd *dnd;
  64         struct wl_array types;
  65         const char *drag_type;
  66         uint32_t tag;
  67         int x, y;
  68 };
  69
  70 struct item {
  71         cairo_surface_t *surface;
  72         int seed;
  73         int x, y;
  74 };
  75
  76 struct dnd_flower_message {
  77         int seed, x_offset, y_offset;
  78 };
  79
  80
  81 static const int item_width = 64;
  82 static const int item_height = 64;
  83 static const int item_padding = 16;
  84
  85 static struct item *
  86 item_create(struct display *display, int x, int y, int seed)
  87 {
  88         struct item *item;
  89         struct timeval tv;
  90
  91         item = malloc(sizeof *item);
  92         if (item == NULL)
  93                 return NULL;
  94
  95
  96         gettimeofday(&tv, NULL);
  97         item->seed = seed ? seed : tv.tv_usec;
  98         srandom(item->seed);
  99
 100         const int petal_count = 3 + random() % 5;
 101         const double r1 = 20 + random() % 10;
 102         const double r2 = 5 + random() % 12;
 103         const double u = (10 + random() % 90) / 100.0;
 104         const double v = (random() % 90) / 100.0;
 105
 106         cairo_t *cr;
 107         int i;
 108         double t, dt = 2 * M_PI / (petal_count * 2);
 109         double x1, y1, x2, y2, x3, y3;
 110         struct rectangle rect;
 111
 112
 113         rect.width = item_width;
 114         rect.height = item_height;
 115         item->surface = display_create_surface(display, &rect);
 116
 117         item->x = x;
 118         item->y = y;
 119
 120         cr = cairo_create(item->surface);
 121         cairo_set_operator(cr, CAIRO_OPERATOR_SOURCE);
 122         cairo_set_source_rgba(cr, 0, 0, 0, 0);
 123         cairo_paint(cr);
 124
 125         cairo_set_operator(cr, CAIRO_OPERATOR_OVER);
 126         cairo_translate(cr, item_width / 2, item_height / 2);
 127         t = random();
 128         cairo_move_to(cr, cos(t) * r1, sin(t) * r1);
 129         for (i = 0; i < petal_count; i++, t += dt * 2) {
 130                 x1 = cos(t) * r1;
 131                 y1 = sin(t) * r1;
 132                 x2 = cos(t + dt) * r2;
 133                 y2 = sin(t + dt) * r2;
 134                 x3 = cos(t + 2 * dt) * r1;
 135                 y3 = sin(t + 2 * dt) * r1;
 136
 137                 cairo_curve_to(cr,
 138                                x1 - y1 * u, y1 + x1 * u,
 139                                x2 + y2 * v, y2 - x2 * v,
 140                                x2, y2);
 141
 142                 cairo_curve_to(cr,
 143                                x2 - y2 * v, y2 + x2 * v,
 144                                x3 + y3 * u, y3 - x3 * u,
 145                                x3, y3);
 146         }
 147
 148         cairo_close_path(cr);
 149
 150         cairo_set_source_rgba(cr,
 151                               0.5 + (random() % 50) / 49.0,
 152                               0.5 + (random() % 50) / 49.0,
 153                               0.5 + (random() % 50) / 49.0,
 154                               0.5 + (random() % 100) / 99.0);
 155
 156         cairo_fill_preserve(cr);
 157
 158         cairo_set_line_width(cr, 1);
 159         cairo_set_source_rgba(cr,
 160                               0.5 + (random() % 50) / 49.0,
 161                               0.5 + (random() % 50) / 49.0,
 162                               0.5 + (random() % 50) / 49.0,
 163                               0.5 + (random() % 100) / 99.0);
 164         cairo_stroke(cr);
 165
 166         cairo_destroy(cr);
 167
 168         return item;
 169 }
 170
 171 static void
 172 dnd_draw(struct dnd *dnd)
 173 {
 174         struct rectangle rectangle;
 175         cairo_t *cr;
 176         cairo_surface_t *wsurface, *surface;
 177         int i;
 178
 179         window_draw(dnd->window);
 180
 181         window_get_child_rectangle(dnd->window, &rectangle);
 182
 183         wsurface = window_get_surface(dnd->window);
 184         surface = cairo_surface_create_similar(wsurface,
 185                                                CAIRO_CONTENT_COLOR_ALPHA,
 186                                                rectangle.width,
 187                                                rectangle.height);
 188         cairo_surface_destroy(wsurface);
 189
 190         cr = cairo_create(surface);
 191         cairo_set_operator(cr, CAIRO_OPERATOR_SOURCE);
 192         cairo_set_source_rgba(cr, 0, 0, 0, 0.8);
 193         cairo_paint(cr);
 194
 195         cairo_set_operator(cr, CAIRO_OPERATOR_OVER);
 196         for (i = 0; i < ARRAY_LENGTH(dnd->items); i++) {
 197                 if (!dnd->items[i])
 198                         continue;
 199                 cairo_set_source_surface(cr, dnd->items[i]->surface,
 200                                          dnd->items[i]->x, dnd->items[i]->y);
 201                 cairo_paint(cr);
 202         }
 203
 204         cairo_destroy(cr);
 205
 206         window_copy_surface(dnd->window, &rectangle, surface);
 207         cairo_surface_destroy(surface);
 208         window_flush(dnd->window);
 209 }
 210
 211 static void
 212 redraw_handler(struct window *window, void *data)
 213 {
 214         struct dnd *dnd = data;
 215
 216         dnd_draw(dnd);
 217 }
 218
 219 static void
 220 keyboard_focus_handler(struct window *window,
 221                        struct input *device, void *data)
 222 {
 223         struct dnd *dnd = data;
 224
 225         window_schedule_redraw(dnd->window);
 226 }
 227
 228 static void
 229 dnd_offer_destroy(struct dnd_offer *dnd_offer)
 230 {
 231         dnd_offer->refcount--;
 232         if (dnd_offer->refcount == 0) {
 233                 wl_array_release(&dnd_offer->types);
 234                 free(dnd_offer);
 235         }
 236 }
 237
 238 static int
 239 dnd_add_item(struct dnd *dnd, struct item *item)
 240 {
 241         int i;
 242
 243         for (i = 0; i < ARRAY_LENGTH(dnd->items); i++) {
 244                 if (dnd->items[i] == 0) {
 245                         dnd->items[i] = item;
 246                         return i;
 247                 }
 248         }
 249         return -1;
 250 }
 251
 252 static struct item *
 253 dnd_get_item(struct dnd *dnd, int32_t x, int32_t y)
 254 {
 255         struct item *item;
 256         struct rectangle rectangle;
 257         int i;
 258
 259         window_get_child_rectangle(dnd->window, &rectangle);
 260
 261         x -= rectangle.x;
 262         y -= rectangle.y;
 263
 264         for (i = 0; i < ARRAY_LENGTH(dnd->items); i++) {
 265                 item = dnd->items[i];
 266                 if (item &&
 267                     item->x <= x && x < item->x + item_width &&
 268                     item->y <= y && y < item->y + item_height)
 269                         return item;
 270         }
 271
 272         return NULL;
 273 }
 274
 275 static void
 276 drag_target(void *data,
 277             struct wl_drag *drag, const char *mime_type)
 278 {
 279         struct dnd_drag *dnd_drag = data;
 280         struct dnd *dnd = dnd_drag->dnd;
 281         struct wl_input_device *device;
 282         cairo_surface_t *surface;
 283         struct wl_buffer *buffer;
 284
 285         fprintf(stderr, "target %s\n", mime_type);
 286         device = input_get_input_device(dnd_drag->input);
 287         dnd_drag->mime_type = mime_type;
 288         if (mime_type)
 289                 surface = dnd_drag->opaque;
 290         else
 291                 surface = dnd_drag->translucent;
 292
 293         buffer = display_get_buffer_for_surface(dnd->display, surface);
 294         wl_input_device_attach(device, dnd_drag->time, buffer,
 295                                dnd_drag->hotspot_x, dnd_drag->hotspot_y);
 296 }
 297
 298 static void
 299 drag_finish(void *data, struct wl_drag *drag, int fd)
 300 {
 301         struct dnd_drag *dnd_drag = data;
 302
 303         if (!dnd_drag->mime_type) {
 304                 dnd_add_item(dnd_drag->dnd, dnd_drag->item);
 305                 window_schedule_redraw(dnd_drag->dnd->window);
 306                 return;
 307         }
 308
 309         struct dnd_flower_message dnd_flower_message;
 310
 311
 312         dnd_flower_message.seed = dnd_drag->item->seed;
 313
 314         dnd_flower_message.x_offset = dnd_drag->x_offset;
 315         dnd_flower_message.y_offset = dnd_drag->y_offset;
 316
 317         fprintf(stderr, "got 'finish', fd %d, sending dnd_flower_message\n", fd);
 318
 319         write(fd, &dnd_flower_message, sizeof dnd_flower_message);
 320         close(fd);
 321
 322         /* The 'finish' event marks the end of the session on the drag
 323          * source side and we need to clean up the drag object created
 324          * and the local state. */
 325         wl_drag_destroy(drag);
 326
 327         /* Destroy the item that has been dragged out */
 328         cairo_surface_destroy(dnd_drag->item->surface);
 329         free(dnd_drag->item);
 330
 331         cairo_surface_destroy(dnd_drag->translucent);
 332         cairo_surface_destroy(dnd_drag->opaque);
 333         free(dnd_drag);
 334 }
 335
 336 static void
 337 drag_reject(void *data, struct wl_drag *drag)
 338 {
 339         struct dnd_drag *dnd_drag = data;
 340
 341         dnd_add_item(dnd_drag->dnd, dnd_drag->item);
 342         window_schedule_redraw(dnd_drag->dnd->window);
 343 }
 344
 345 static const struct wl_drag_listener drag_listener = {
 346         drag_target,
 347         drag_finish,
 348         drag_reject
 349 };
 350
 351 static void
 352 drag_offer_offer(void *data,
 353                  struct wl_drag_offer *offer, const char *type)
 354 {
 355         struct dnd_offer *dnd_offer = data;
 356         char **p;
 357
 358         p = wl_array_add(&dnd_offer->types, sizeof *p);
 359         if (p)
 360                 *p = strdup(type);
 361 }
 362
 363 static void
 364 drag_offer_pointer_focus(void *data,
 365                          struct wl_drag_offer *offer,
 366                          uint32_t time, struct wl_surface *surface,
 367                          int32_t x, int32_t y,
 368                          int32_t surface_x, int32_t surface_y)
 369 {
 370         struct dnd_offer *dnd_offer = data;
 371         struct window *window;
 372         char **p, **end;
 373
 374         /* The last event in a dnd session is pointer_focus with a
 375          * NULL surface, whether or not we get the drop event.  We
 376          * need to clean up the dnd_offer proxy and whatever state we
 377          * allocated. */
 378         if (!surface) {
 379                 fprintf(stderr, "pointer focus NULL, session over\n");
 380                 wl_drag_offer_destroy(offer);
 381                 dnd_offer_destroy(dnd_offer);
 382                 return;
 383         }
 384
 385         fprintf(stderr, "drag pointer focus %p\n", surface);
 386         fprintf(stderr, "offered types:\n");
 387         end = dnd_offer->types.data + dnd_offer->types.size;
 388         for (p = dnd_offer->types.data; p < end; p++)
 389                 fprintf(stderr, "\%s\n", *p);
 390
 391         window = wl_surface_get_user_data(surface);
 392         dnd_offer->dnd = window_get_user_data(window);
 393
 394         if (!dnd_get_item(dnd_offer->dnd, surface_x, surface_y)) {
 395                 wl_drag_offer_accept(offer, time, "application/x-wayland-dnd-flower");
 396                 dnd_offer->drag_type = "application/x-wayland-dnd-flower";
 397                 dnd_offer->x = surface_x;
 398                 dnd_offer->y = surface_y;
 399         } else {
 400                 wl_drag_offer_accept(offer, time, NULL);
 401                 dnd_offer->drag_type = NULL;
 402         }
 403 }
 404
 405 static void
 406 drag_offer_motion(void *data,
 407                   struct wl_drag_offer *offer, uint32_t time,
 408                   int32_t x, int32_t y, int32_t surface_x, int32_t surface_y)
 409 {
 410         struct dnd_offer *dnd_offer = data;
 411
 412         if (!dnd_get_item(dnd_offer->dnd, surface_x, surface_y)) {
 413                 fprintf(stderr, "drag offer motion %d, %d, accepting\n",
 414                         surface_x, surface_y);
 415                 wl_drag_offer_accept(offer, time, "application/x-wayland-dnd-flower");
 416                 dnd_offer->drag_type = "application/x-wayland-dnd-flower";
 417                 dnd_offer->x = surface_x;
 418                 dnd_offer->y = surface_y;
 419         } else {
 420                 fprintf(stderr, "drag offer motion %d, %d, declining\n",
 421                         surface_x, surface_y);
 422                 wl_drag_offer_accept(offer, time, NULL);
 423                 dnd_offer->drag_type = NULL;
 424         }
 425 }
 426
 427 static gboolean
 428 drop_io_func(GIOChannel *source, GIOCondition condition, gpointer data)
 429 {
 430         struct dnd_offer *dnd_offer = data;
 431         struct dnd *dnd = dnd_offer->dnd;
 432         struct dnd_flower_message dnd_flower_message;
 433         int fd;
 434         unsigned int len;
 435         struct item *item;
 436
 437         fd = g_io_channel_unix_get_fd(source);
 438         len = read(fd, &dnd_flower_message, sizeof dnd_flower_message);
 439         fprintf(stderr, "read %d bytes\n", len);
 440
 441         close(fd);
 442         g_source_remove(dnd_offer->tag);
 443
 444         g_io_channel_unref(source);
 445
 446         item = item_create(dnd->display,
 447                            dnd_offer->x - dnd_flower_message.x_offset - 26,
 448                            dnd_offer->y - dnd_flower_message.y_offset - 66,
 449                            dnd_flower_message.seed);
 450
 451         dnd_add_item(dnd, item);
 452         window_schedule_redraw(dnd->window);
 453
 454         dnd_offer_destroy(dnd_offer);
 455
 456         return TRUE;
 457 }
 458
 459 static void
 460 drag_offer_drop(void *data, struct wl_drag_offer *offer)
 461 {
 462         struct dnd_offer *dnd_offer = data;
 463         GIOChannel *channel;
 464         int p[2];
 465
 466         if (!dnd_offer->drag_type) {
 467                 fprintf(stderr, "got 'drop', but no target\n");
 468                 wl_drag_offer_reject(offer);
 469                 return;
 470         }
 471
 472         fprintf(stderr, "got 'drop', sending write end of pipe\n");
 473
 474         dnd_offer->refcount++;
 475         pipe(p);
 476         wl_drag_offer_receive(offer, p[1]);
 477         close(p[1]);
 478
 479         channel = g_io_channel_unix_new(p[0]);
 480         dnd_offer->tag = g_io_add_watch(channel, G_IO_IN,
 481                                         drop_io_func, dnd_offer);
 482 }
 483
 484 static const struct wl_drag_offer_listener drag_offer_listener = {
 485         drag_offer_offer,
 486         drag_offer_pointer_focus,
 487         drag_offer_motion,
 488         drag_offer_drop,
 489 };
 490
 491 static void
 492 drag_offer_handler(struct wl_drag_offer *offer, struct display *display)
 493 {
 494         struct dnd_offer *dnd_offer;
 495
 496         dnd_offer = malloc(sizeof *dnd_offer);
 497         if (dnd_offer == NULL)
 498                 return;
 499
 500         dnd_offer->refcount = 1;
 501
 502         wl_drag_offer_add_listener(offer, &drag_offer_listener, dnd_offer);
 503         wl_array_init(&dnd_offer->types);
 504 }
 505
 506 static cairo_surface_t *
 507 create_drag_cursor(struct dnd_drag *dnd_drag,
 508                    struct item *item, int32_t x, int32_t y, double opacity)
 509 {
 510         struct dnd *dnd = dnd_drag->dnd;
 511         cairo_surface_t *surface, *pointer;
 512         int32_t pointer_width, pointer_height, hotspot_x, hotspot_y;
 513         struct rectangle rectangle;
 514         cairo_pattern_t *pattern;
 515         cairo_t *cr;
 516
 517         pointer = display_get_pointer_surface(dnd->display,
 518                                               POINTER_DRAGGING,
 519                                               &pointer_width,
 520                                               &pointer_height,
 521                                               &hotspot_x,
 522                                               &hotspot_y);
 523
 524         rectangle.width = item_width + 2 * pointer_width;
 525         rectangle.height = item_height + 2 * pointer_height;
 526         surface = display_create_surface(dnd->display, &rectangle);
 527
 528         cr = cairo_create(surface);
 529         cairo_translate(cr, pointer_width, pointer_height);
 530
 531         cairo_set_operator(cr, CAIRO_OPERATOR_SOURCE);
 532         cairo_set_source_rgba(cr, 0, 0, 0, 0);
 533         cairo_paint(cr);
 534
 535         cairo_set_operator(cr, CAIRO_OPERATOR_OVER);
 536         cairo_set_source_surface(cr, item->surface, 0, 0);
 537         pattern = cairo_pattern_create_rgba(0, 0, 0, opacity);
 538         cairo_mask(cr, pattern);
 539         cairo_pattern_destroy(pattern);
 540
 541         cairo_set_source_surface(cr, pointer,
 542                                  x - item->x - hotspot_x,
 543                                  y - item->y - hotspot_y);
 544         cairo_surface_destroy(pointer);
 545         cairo_paint(cr);
 546         /* FIXME: more cairo-gl brokeness */
 547         display_flush_cairo_device(dnd->display);
 548         cairo_destroy(cr);
 549
 550         dnd_drag->hotspot_x = pointer_width + x - item->x;
 551         dnd_drag->hotspot_y = pointer_height + y - item->y;
 552
 553         return surface;
 554 }
 555
 556 static void
 557 dnd_button_handler(struct window *window,
 558                    struct input *input, uint32_t time,
 559                    int button, int state, void *data)
 560 {
 561         struct dnd *dnd = data;
 562         int32_t x, y;
 563         struct item *item;
 564         struct rectangle rectangle;
 565         struct dnd_drag *dnd_drag;
 566         struct wl_drag *drag;
 567         int i;
 568
 569         window_get_child_rectangle(dnd->window, &rectangle);
 570         input_get_position(input, &x, &y);
 571         item = dnd_get_item(dnd, x, y);
 572         x -= rectangle.x;
 573         y -= rectangle.y;
 574
 575         if (item && state == 1) {
 576                 fprintf(stderr, "start drag, item %p\n", item);
 577
 578                 dnd_drag = malloc(sizeof *dnd_drag);
 579                 dnd_drag->dnd = dnd;
 580                 dnd_drag->input = input;
 581                 dnd_drag->time = time;
 582                 dnd_drag->item = item;
 583                 dnd_drag->x_offset = x - item->x;
 584                 dnd_drag->y_offset = y - item->y;
 585
 586                 for (i = 0; i < ARRAY_LENGTH(dnd->items); i++) {
 587                         if (item == dnd->items[i]){
 588                                 dnd->items[i] = 0;
 589                                 break;
 590                         }
 591                 }
 592
 593                 dnd_drag->opaque =
 594                         create_drag_cursor(dnd_drag, item, x, y, 1);
 595                 dnd_drag->translucent =
 596                         create_drag_cursor(dnd_drag, item, x, y, 0.2);
 597
 598                 drag = window_create_drag(window);
 599                 wl_drag_offer(drag, "application/x-wayland-dnd-flower");
 600                 window_activate_drag(drag, window, input, time);
 601                 wl_drag_add_listener(drag, &drag_listener, dnd_drag);
 602                 window_schedule_redraw(dnd->window);
 603         }
 604 }
 605
 606 static int
 607 dnd_motion_handler(struct window *window,
 608                    struct input *input, uint32_t time,
 609                    int32_t x, int32_t y,
 610                    int32_t sx, int32_t sy, void *data)
 611 {
 612         struct dnd *dnd = data;
 613         struct item *item;
 614
 615         item = dnd_get_item(dnd, sx, sy);
 616
 617         if (item)
 618                 return POINTER_HAND1;
 619         else
 620                 return POINTER_LEFT_PTR;
 621 }
 622
 623 static struct dnd *
 624 dnd_create(struct display *display)
 625 {
 626         struct dnd *dnd;
 627         gchar *title;
 628         int i, x, y;
 629         struct rectangle rectangle;
 630
 631         dnd = malloc(sizeof *dnd);
 632         if (dnd == NULL)
 633                 return dnd;
 634         memset(dnd, 0, sizeof *dnd);
 635
 636         title = g_strdup_printf("Wayland Drag and Drop Demo");
 637
 638         dnd->window = window_create(display, title, 100, 100, 500, 400);
 639         dnd->display = display;
 640         dnd->key = 100;
 641
 642         for (i = 0; i < ARRAY_LENGTH(dnd->items); i++) {
 643                 x = (i % 4) * (item_width + item_padding) + item_padding;
 644                 y = (i / 4) * (item_height + item_padding) + item_padding;
 645                 if ((i ^ (i >> 2)) & 1)
 646                         dnd->items[i] = item_create(display, x, y, 0);
 647                 else
 648                         dnd->items[i] = NULL;
 649         }
 650
 651         window_set_user_data(dnd->window, dnd);
 652         window_set_redraw_handler(dnd->window, redraw_handler);
 653         window_set_keyboard_focus_handler(dnd->window,
 654                                           keyboard_focus_handler);
 655         window_set_button_handler(dnd->window,
 656                                   dnd_button_handler);
 657
 658         window_set_motion_handler(dnd->window,
 659                                   dnd_motion_handler);
 660
 661         rectangle.width = 4 * (item_width + item_padding) + item_padding;
 662         rectangle.height = 4 * (item_height + item_padding) + item_padding;
 663         window_set_child_size(dnd->window, &rectangle);
 664
 665         dnd_draw(dnd);
 666
 667         return dnd;
 668 }
 669
 670 static const GOptionEntry option_entries[] = {
 671         { NULL }
 672 };
 673
 674 int
 675 main(int argc, char *argv[])
 676 {
 677         struct display *d;
 678         struct dnd *dnd;
 679
 680         d = display_create(&argc, &argv, option_entries);
 681         if (d == NULL) {
 682                 fprintf(stderr, "failed to create display: %m\n");
 683                 return -1;
 684         }
 685
 686         display_set_drag_offer_handler(d, drag_offer_handler);
 687
 688         dnd = dnd_create (d);
 689
 690         display_run(d);
 691
 692         return 0;
 693 }