src/event-context.cpp

   1 #define __SP_EVENT_CONTEXT_C__
   2
   3 /** \file
   4  * Main event handling, and related helper functions.
   5  *
   6  * Authors:
   7  *   Lauris Kaplinski <lauris@kaplinski.com>
   8  *   Frank Felfe <innerspace@iname.com>
   9  *   bulia byak <buliabyak@users.sf.net>
  10  *
  11  * Copyright (C) 1999-2005 authors
  12  * Copyright (C) 2001-2002 Ximian, Inc.
  13  *
  14  * Released under GNU GPL, read the file 'COPYING' for more information
  15  */
  16
  17 /** \class SPEventContext
  18  * SPEventContext is an abstract base class of all tools. As the name
  19  * indicates, event context implementations process UI events (mouse
  20  * movements and keypresses) and take actions (like creating or modifying
  21  * objects).  There is one event context implementation for each tool,
  22  * plus few abstract base classes. Writing a new tool involves
  23  * subclassing SPEventContext.
  24  */
  25
  26 #ifdef HAVE_CONFIG_H
  27 # include "config.h"
  28 #endif
  29
  30 #include "event-context.h"
  31
  32 #include <string.h>
  33 #include <gdk/gdkkeysyms.h>
  34 #include <gtk/gtkmain.h>
  35 #include <gtk/gtkmenu.h>
  36 #include <glibmm/i18n.h>
  37 #include <cstring>
  38 #include <string>
  39
  40 #include "display/sp-canvas.h"
  41 #include "xml/node-event-vector.h"
  42 #include "sp-cursor.h"
  43 #include "shortcuts.h"
  44 #include "desktop.h"
  45 #include "desktop-handles.h"
  46 #include "sp-namedview.h"
  47 #include "selection.h"
  48 #include "file.h"
  49 #include "interface.h"
  50 #include "macros.h"
  51 #include "tools-switch.h"
  52 #include "preferences.h"
  53 #include "message-context.h"
  54 #include "gradient-drag.h"
  55 #include "object-edit.h"
  56 #include "attributes.h"
  57 #include "rubberband.h"
  58 #include "selcue.h"
  59 #include "lpe-tool-context.h"
  60
  61 static void sp_event_context_class_init(SPEventContextClass *klass);
  62 static void sp_event_context_init(SPEventContext *event_context);
  63 static void sp_event_context_dispose(GObject *object);
  64
  65 static void sp_event_context_private_setup(SPEventContext *ec);
  66 static gint sp_event_context_private_root_handler(SPEventContext *event_context, GdkEvent *event);
  67 static gint sp_event_context_private_item_handler(SPEventContext *event_context, SPItem *item, GdkEvent *event);
  68
  69 static void set_event_location(SPDesktop * desktop, GdkEvent * event);
  70
  71 static GObjectClass *parent_class;
  72
  73 // globals for temporary switching to selector by space
  74 static bool selector_toggled = FALSE;
  75 static int switch_selector_to = 0;
  76
  77 // globals for temporary switching to dropper by 'D'
  78 static bool dropper_toggled = FALSE;
  79 static int switch_dropper_to = 0;
  80
  81 static gint xp = 0, yp = 0; // where drag started
  82 static gint tolerance = 0;
  83 static bool within_tolerance = false;
  84
  85 // globals for keeping track of keyboard scroll events in order to accelerate
  86 static guint32 scroll_event_time = 0;
  87 static gdouble scroll_multiply = 1;
  88 static guint scroll_keyval = 0;
  89
  90 /**
  91  * Registers the SPEventContext class with Glib and returns its type number.
  92  */
  93 GType
  94 sp_event_context_get_type(void)
  95 {
  96     static GType type = 0;
  97     if (!type) {
  98         GTypeInfo info = {
  99             sizeof(SPEventContextClass),
 100             NULL, NULL,
 101             (GClassInitFunc) sp_event_context_class_init,
 102             NULL, NULL,
 103             sizeof(SPEventContext),
 104             4,
 105             (GInstanceInitFunc) sp_event_context_init,
 106             NULL,    /* value_table */
 107         };
 108         type = g_type_register_static(G_TYPE_OBJECT, "SPEventContext", &info, (GTypeFlags)0);
 109     }
 110     return type;
 111 }
 112
 113 /**
 114  * Callback to set up the SPEventContext vtable.
 115  */
 116 static void
 117 sp_event_context_class_init(SPEventContextClass *klass)
 118 {
 119     GObjectClass *object_class;
 120
 121     object_class = (GObjectClass *) klass;
 122
 123     parent_class = (GObjectClass*)g_type_class_peek_parent(klass);
 124
 125     object_class->dispose = sp_event_context_dispose;
 126
 127     klass->setup = sp_event_context_private_setup;
 128     klass->root_handler = sp_event_context_private_root_handler;
 129     klass->item_handler = sp_event_context_private_item_handler;
 130 }
 131
 132 /**
 133  * Clears all SPEventContext object members.
 134  */
 135 static void
 136 sp_event_context_init(SPEventContext *event_context)
 137 {
 138     event_context->desktop = NULL;
 139     event_context->cursor = NULL;
 140     event_context->_message_context = NULL;
 141     event_context->_selcue = NULL;
 142     event_context->_grdrag = NULL;
 143     event_context->space_panning = false;
 144     event_context->shape_editor = NULL;
 145     event_context->_delayed_snap_event = NULL;
 146 }
 147
 148 /**
 149  * Callback to free and null member variables of SPEventContext object.
 150  */
 151 static void
 152 sp_event_context_dispose(GObject *object)
 153 {
 154     SPEventContext *ec;
 155
 156     ec = SP_EVENT_CONTEXT(object);
 157
 158     if (ec->_message_context) {
 159         delete ec->_message_context;
 160     }
 161
 162     if (ec->cursor != NULL) {
 163         gdk_cursor_unref(ec->cursor);
 164         ec->cursor = NULL;
 165     }
 166
 167     if (ec->desktop) {
 168         ec->desktop = NULL;
 169     }
 170
 171     if (ec->pref_observer) {
 172         delete ec->pref_observer;
 173     }
 174
 175     if (ec->_delayed_snap_event) {
 176         delete ec->_delayed_snap_event;
 177     }
 178
 179     G_OBJECT_CLASS(parent_class)->dispose(object);
 180 }
 181
 182 /**
 183  * Recreates and draws cursor on desktop related to SPEventContext.
 184  */
 185 void
 186 sp_event_context_update_cursor(SPEventContext *ec)
 187 {
 188     GtkWidget *w = GTK_WIDGET(sp_desktop_canvas(ec->desktop));
 189     if (w->window) {
 190         /* fixme: */
 191         if (ec->cursor_shape) {
 192             GdkBitmap *bitmap = NULL;
 193             GdkBitmap *mask = NULL;
 194             sp_cursor_bitmap_and_mask_from_xpm(&bitmap, &mask, ec->cursor_shape);
 195             if ((bitmap != NULL) && (mask != NULL)) {
 196                 if (ec->cursor)
 197                     gdk_cursor_unref (ec->cursor);
 198                 ec->cursor = gdk_cursor_new_from_pixmap(bitmap, mask,
 199                                                         &w->style->black,
 200                                                         &w->style->white,
 201                                                         ec->hot_x, ec->hot_y);
 202                 g_object_unref (bitmap);
 203                 g_object_unref (mask);
 204             }
 205         }
 206         gdk_window_set_cursor(w->window, ec->cursor);
 207         gdk_flush();
 208     }
 209     ec->desktop->waiting_cursor = false;
 210 }
 211
 212 /**
 213  * Callback that gets called on initialization of SPEventContext object.
 214  * Redraws mouse cursor, at the moment.
 215  */
 216 static void
 217 sp_event_context_private_setup(SPEventContext *ec)
 218 {
 219     sp_event_context_update_cursor(ec);
 220 }
 221
 222 /**
 223  * \brief   Gobbles next key events on the queue with the same keyval and mask. Returns the number of events consumed.
 224  */
 225 gint gobble_key_events(guint keyval, gint mask)
 226 {
 227     GdkEvent *event_next;
 228     gint i = 0;
 229
 230     event_next = gdk_event_get();
 231     // while the next event is also a key notify with the same keyval and mask,
 232     while (event_next && (event_next->type == GDK_KEY_PRESS || event_next->type == GDK_KEY_RELEASE)
 233            && event_next->key.keyval == keyval
 234            && (!mask || (event_next->key.state & mask))) {
 235         if (event_next->type == GDK_KEY_PRESS)
 236             i ++;
 237         // kill it
 238         gdk_event_free(event_next);
 239         // get next
 240         event_next = gdk_event_get();
 241     }
 242     // otherwise, put it back onto the queue
 243     if (event_next) gdk_event_put(event_next);
 244
 245     return i;
 246 }
 247
 248 /**
 249  * \brief   Gobbles next motion notify events on the queue with the same mask. Returns the number of events consumed.
 250 */
 251 gint gobble_motion_events(gint mask)
 252 {
 253     GdkEvent *event_next;
 254     gint i = 0;
 255
 256     event_next = gdk_event_get();
 257     // while the next event is also a key notify with the same keyval and mask,
 258     while (event_next && event_next->type == GDK_MOTION_NOTIFY
 259            && (event_next->motion.state & mask)) {
 260         // kill it
 261         gdk_event_free(event_next);
 262         // get next
 263         event_next = gdk_event_get();
 264         i ++;
 265     }
 266     // otherwise, put it back onto the queue
 267     if (event_next) gdk_event_put(event_next);
 268
 269     return i;
 270 }
 271
 272 /**
 273  * Toggles current tool between active tool and selector tool.
 274  * Subroutine of sp_event_context_private_root_handler().
 275  */
 276 static void
 277 sp_toggle_selector(SPDesktop *dt)
 278 {
 279     if (!dt->event_context) return;
 280
 281     if (tools_isactive(dt, TOOLS_SELECT)) {
 282         if (selector_toggled) {
 283             if (switch_selector_to) tools_switch (dt, switch_selector_to);
 284             selector_toggled = FALSE;
 285         } else return;
 286     } else {
 287         selector_toggled = TRUE;
 288         switch_selector_to = tools_active(dt);
 289         tools_switch (dt, TOOLS_SELECT);
 290     }
 291 }
 292
 293 /**
 294  * Toggles current tool between active tool and dropper tool.
 295  * Subroutine of sp_event_context_private_root_handler().
 296  */
 297 static void
 298 sp_toggle_dropper(SPDesktop *dt)
 299 {
 300     if (!dt->event_context) return;
 301
 302     if (tools_isactive(dt, TOOLS_DROPPER)) {
 303         if (dropper_toggled) {
 304             if (switch_dropper_to) tools_switch (dt, switch_dropper_to);
 305             dropper_toggled = FALSE;
 306         } else return;
 307     } else {
 308         dropper_toggled = TRUE;
 309         switch_dropper_to = tools_active(dt);
 310         tools_switch (dt, TOOLS_DROPPER);
 311     }
 312 }
 313
 314 /**
 315  * Calculates and keeps track of scroll acceleration.
 316  * Subroutine of sp_event_context_private_root_handler().
 317  */
 318 static gdouble accelerate_scroll(GdkEvent *event, gdouble acceleration, SPCanvas */*canvas*/)
 319 {
 320     guint32 time_diff = ((GdkEventKey *) event)->time - scroll_event_time;
 321
 322     /* key pressed within 500ms ? (1/2 second) */
 323     if (time_diff > 500 || event->key.keyval != scroll_keyval) {
 324         scroll_multiply = 1; // abort acceleration
 325     } else {
 326         scroll_multiply += acceleration; // continue acceleration
 327     }
 328
 329     scroll_event_time = ((GdkEventKey *) event)->time;
 330     scroll_keyval = event->key.keyval;
 331
 332     return scroll_multiply;
 333 }
 334
 335 /**
 336  * Main event dispatch, gets called from Gdk.
 337  */
 338 static gint sp_event_context_private_root_handler(SPEventContext *event_context, GdkEvent *event)
 339 {
 340     static Geom::Point button_w;
 341     static unsigned int panning = 0;
 342     static unsigned int zoom_rb = 0;
 343
 344     SPDesktop *desktop = event_context->desktop;
 345     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 346
 347     /// @todo REmove redundant /value in preference keys
 348     tolerance = prefs->getIntLimited(
 349             "/options/dragtolerance/value", 0, 0, 100);
 350
 351     gint ret = FALSE;
 352
 353     switch (event->type) {
 354         case GDK_2BUTTON_PRESS:
 355             if (panning) {
 356                 panning = 0;
 357                 sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate),
 358                         event->button.time);
 359                 ret = TRUE;
 360             } else {
 361                 /* sp_desktop_dialog(); */
 362             }
 363             break;
 364         case GDK_BUTTON_PRESS:
 365
 366             // save drag origin
 367             xp = (gint) event->button.x;
 368             yp = (gint) event->button.y;
 369             within_tolerance = true;
 370
 371             button_w = Geom::Point(event->button.x, event->button.y);
 372
 373             switch (event->button.button) {
 374                 case 1:
 375                     if (event_context->space_panning) {
 376                         // When starting panning, make sure there are no snap events pending because these might disable the panning again
 377                         sp_event_context_discard_delayed_snap_event(event_context);
 378                         panning = 1;
 379                         sp_canvas_item_grab(SP_CANVAS_ITEM(desktop->acetate),
 380                             GDK_KEY_RELEASE_MASK | GDK_BUTTON_RELEASE_MASK | GDK_POINTER_MOTION_MASK | GDK_POINTER_MOTION_HINT_MASK,
 381                             NULL, event->button.time-1);
 382                         ret = TRUE;
 383                     }
 384                     break;
 385                 case 2:
 386                     if (event->button.state & GDK_SHIFT_MASK) {
 387                         zoom_rb = 2;
 388                     } else {
 389                         // When starting panning, make sure there are no snap events pending because these might disable the panning again
 390                                                 sp_event_context_discard_delayed_snap_event(event_context);
 391                                                 panning = 2;
 392                         sp_canvas_item_grab(SP_CANVAS_ITEM(desktop->acetate),
 393                             GDK_BUTTON_RELEASE_MASK | GDK_POINTER_MOTION_MASK | GDK_POINTER_MOTION_HINT_MASK,
 394                             NULL, event->button.time-1);
 395                     }
 396                     ret = TRUE;
 397                     break;
 398                 case 3:
 399                     if (event->button.state & GDK_SHIFT_MASK
 400                             || event->button.state & GDK_CONTROL_MASK) {
 401                         // When starting panning, make sure there are no snap events pending because these might disable the panning again
 402                                                 sp_event_context_discard_delayed_snap_event(event_context);
 403                         panning = 3;
 404                         sp_canvas_item_grab(SP_CANVAS_ITEM(desktop->acetate),
 405                                 GDK_BUTTON_RELEASE_MASK | GDK_POINTER_MOTION_MASK | GDK_POINTER_MOTION_HINT_MASK,
 406                                 NULL, event->button.time);
 407                         ret = TRUE;
 408                     } else {
 409                         sp_event_root_menu_popup(desktop, NULL, event);
 410                     }
 411                     break;
 412                 default:
 413                     break;
 414             }
 415             break;
 416         case GDK_MOTION_NOTIFY:
 417             if (panning) {
 418                 if ((panning == 2 && !(event->motion.state & GDK_BUTTON2_MASK))
 419                         || (panning == 1 && !(event->motion.state & GDK_BUTTON1_MASK))
 420                         || (panning == 3 && !(event->motion.state & GDK_BUTTON3_MASK))
 421                    ) {
 422                     /* Gdk seems to lose button release for us sometimes :-( */
 423                         panning = 0;
 424                     sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate),
 425                             event->button.time);
 426                     ret = TRUE;
 427                 } else {
 428                     if ( within_tolerance
 429                          && ( abs( (gint) event->motion.x - xp ) < tolerance )
 430                          && ( abs( (gint) event->motion.y - yp ) < tolerance ))
 431                     {
 432                         // do not drag if we're within tolerance from origin
 433                         break;
 434                     }
 435                     // Once the user has moved farther than tolerance from
 436                     // the original location (indicating they intend to move
 437                     // the object, not click), then always process the motion
 438                     // notify coordinates as given (no snapping back to origin)
 439                     within_tolerance = false;
 440
 441                     // gobble subsequent motion events to prevent "sticking"
 442                     // when scrolling is slow
 443                     gobble_motion_events(panning == 2 ?
 444                                          GDK_BUTTON2_MASK :
 445                                          (panning == 1 ? GDK_BUTTON1_MASK : GDK_BUTTON3_MASK));
 446
 447                     Geom::Point const motion_w(event->motion.x, event->motion.y);
 448                     Geom::Point const moved_w( motion_w - button_w );
 449                     event_context->desktop->scroll_world(moved_w, true); // we're still scrolling, do not redraw
 450                     ret = TRUE;
 451                 }
 452             } else if (zoom_rb) {
 453                 Geom::Point const motion_w(event->motion.x, event->motion.y);
 454                 Geom::Point const motion_dt(desktop->w2d(motion_w));
 455
 456                 if ( within_tolerance
 457                      && ( abs( (gint) event->motion.x - xp ) < tolerance )
 458                      && ( abs( (gint) event->motion.y - yp ) < tolerance ) ) {
 459                     break; // do not drag if we're within tolerance from origin
 460                 }
 461                 // Once the user has moved farther than tolerance from the original location
 462                 // (indicating they intend to move the object, not click), then always process the
 463                 // motion notify coordinates as given (no snapping back to origin)
 464                 within_tolerance = false;
 465
 466                 if (Inkscape::Rubberband::get(desktop)->is_started()) {
 467                     Inkscape::Rubberband::get(desktop)->move(motion_dt);
 468                 } else {
 469                     Inkscape::Rubberband::get(desktop)->start(desktop, motion_dt);
 470                 }
 471                 if (zoom_rb == 2)
 472                     gobble_motion_events(GDK_BUTTON2_MASK);
 473             }
 474             break;
 475         case GDK_BUTTON_RELEASE:
 476             xp = yp = 0;
 477             if (within_tolerance && (panning || zoom_rb)) {
 478                 zoom_rb = 0;
 479                 if (panning) {
 480                     panning = 0;
 481                     sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate),
 482                                       event->button.time);
 483                 }
 484                 Geom::Point const event_w(event->button.x, event->button.y);
 485                 Geom::Point const event_dt(desktop->w2d(event_w));
 486                 double const zoom_inc = prefs->getDoubleLimited("/options/zoomincrement/value", M_SQRT2, 1.01, 10);
 487                 desktop->zoom_relative_keep_point(event_dt,
 488                           (event->button.state & GDK_SHIFT_MASK) ? 1/zoom_inc : zoom_inc);
 489                 desktop->updateNow();
 490                 ret = TRUE;
 491             } else if (panning == event->button.button) {
 492                 panning = 0;
 493                 sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate),
 494                                       event->button.time);
 495
 496                 // in slow complex drawings, some of the motion events are lost;
 497                 // to make up for this, we scroll it once again to the button-up event coordinates
 498                 // (i.e. canvas will always get scrolled all the way to the mouse release point,
 499                 // even if few intermediate steps were visible)
 500                 Geom::Point const motion_w(event->button.x, event->button.y);
 501                 Geom::Point const moved_w( motion_w - button_w );
 502                 event_context->desktop->scroll_world(moved_w);
 503                 desktop->updateNow();
 504                 ret = TRUE;
 505             } else if (zoom_rb == event->button.button) {
 506                 zoom_rb = 0;
 507                 Geom::OptRect const b = Inkscape::Rubberband::get(desktop)->getRectangle();
 508                 Inkscape::Rubberband::get(desktop)->stop();
 509                 if (b && !within_tolerance) {
 510                     desktop->set_display_area(*b, 10);
 511                 }
 512                 ret = TRUE;
 513             }
 514             break;
 515         case GDK_KEY_PRESS:
 516                 {
 517                 double const acceleration = prefs->getDoubleLimited("/options/scrollingacceleration/value", 0, 0, 6);
 518                 int const key_scroll = prefs->getIntLimited("/options/keyscroll/value", 10, 0, 1000);
 519
 520                 switch (get_group0_keyval(&event->key)) {
 521                 // GDK insists on stealing these keys (F1 for no idea what, tab for cycling widgets
 522                 // in the editing window). So we resteal them back and run our regular shortcut
 523                 // invoker on them.
 524                 unsigned int shortcut;
 525                 case GDK_Tab:
 526                 case GDK_ISO_Left_Tab:
 527                 case GDK_F1:
 528                     shortcut = get_group0_keyval(&event->key);
 529                     if (event->key.state & GDK_SHIFT_MASK)
 530                         shortcut |= SP_SHORTCUT_SHIFT_MASK;
 531                     if (event->key.state & GDK_CONTROL_MASK)
 532                         shortcut |= SP_SHORTCUT_CONTROL_MASK;
 533                     if (event->key.state & GDK_MOD1_MASK)
 534                         shortcut |= SP_SHORTCUT_ALT_MASK;
 535                     ret = sp_shortcut_invoke(shortcut, desktop);
 536                     break;
 537
 538                 case GDK_D:
 539                 case GDK_d:
 540                     if (!MOD__SHIFT && !MOD__CTRL && !MOD__ALT) {
 541                         sp_toggle_dropper(desktop);
 542                         ret = TRUE;
 543                     }
 544                     break;
 545                 case GDK_Q:
 546                 case GDK_q:
 547                                         if (desktop->quick_zoomed()) {
 548                                                 ret = TRUE;
 549                                         }
 550                     if (!MOD__SHIFT && !MOD__CTRL && !MOD__ALT) {
 551                                                 desktop->zoom_quick(true);
 552                         ret = TRUE;
 553                     }
 554                     break;
 555                 case GDK_W:
 556                 case GDK_w:
 557                 case GDK_F4:
 558                     /* Close view */
 559                     if (MOD__CTRL_ONLY) {
 560                         sp_ui_close_view(NULL);
 561                         ret = TRUE;
 562                     }
 563                     break;
 564                 case GDK_Left: // Ctrl Left
 565                 case GDK_KP_Left:
 566                 case GDK_KP_4:
 567                     if (MOD__CTRL_ONLY) {
 568                         int i = (int) floor(key_scroll * accelerate_scroll(event, acceleration, sp_desktop_canvas(desktop)));
 569                         gobble_key_events(get_group0_keyval(&event->key),
 570                                 GDK_CONTROL_MASK);
 571                         event_context->desktop->scroll_world(i, 0);
 572                         ret = TRUE;
 573                     }
 574                     break;
 575                 case GDK_Up: // Ctrl Up
 576                 case GDK_KP_Up:
 577                 case GDK_KP_8:
 578                     if (MOD__CTRL_ONLY) {
 579                         int i = (int) floor(key_scroll * accelerate_scroll(event, acceleration, sp_desktop_canvas(desktop)));
 580                         gobble_key_events(get_group0_keyval(&event->key),
 581                                 GDK_CONTROL_MASK);
 582                         event_context->desktop->scroll_world(0, i);
 583                         ret = TRUE;
 584                     }
 585                     break;
 586                 case GDK_Right: // Ctrl Right
 587                 case GDK_KP_Right:
 588                 case GDK_KP_6:
 589                     if (MOD__CTRL_ONLY) {
 590                         int i = (int) floor(key_scroll * accelerate_scroll(event, acceleration, sp_desktop_canvas(desktop)));
 591                         gobble_key_events(get_group0_keyval(&event->key),
 592                                 GDK_CONTROL_MASK);
 593                         event_context->desktop->scroll_world(-i, 0);
 594                         ret = TRUE;
 595                     }
 596                     break;
 597                 case GDK_Down: // Ctrl Down
 598                 case GDK_KP_Down:
 599                 case GDK_KP_2:
 600                     if (MOD__CTRL_ONLY) {
 601                         int i = (int) floor(key_scroll * accelerate_scroll(event, acceleration, sp_desktop_canvas(desktop)));
 602                         gobble_key_events(get_group0_keyval(&event->key),
 603                                 GDK_CONTROL_MASK);
 604                         event_context->desktop->scroll_world(0, -i);
 605                         ret = TRUE;
 606                     }
 607                     break;
 608                 case GDK_F10:
 609                     if (MOD__SHIFT_ONLY) {
 610                         sp_event_root_menu_popup(desktop, NULL, event);
 611                         ret= TRUE;
 612                     }
 613                     break;
 614                 case GDK_space:
 615                     if (prefs->getBool("/options/spacepans/value")) {
 616                         event_context->space_panning = true;
 617                         event_context->_message_context->set(Inkscape::INFORMATION_MESSAGE, _("<b>Space+mouse drag</b> to pan canvas"));
 618                         ret= TRUE;
 619                     } else {
 620                         sp_toggle_selector(desktop);
 621                         ret= TRUE;
 622                     }
 623                     break;
 624                 case GDK_z:
 625                 case GDK_Z:
 626                     if (MOD__ALT_ONLY) {
 627                         desktop->zoom_grab_focus();
 628                         ret = TRUE;
 629                     }
 630                     break;
 631                 default:
 632                     break;
 633             }
 634                 }
 635             break;
 636         case GDK_KEY_RELEASE:
 637             switch (get_group0_keyval(&event->key)) {
 638                 case GDK_space:
 639                     if (event_context->space_panning) {
 640                         event_context->space_panning = false;
 641                         event_context->_message_context->clear();
 642                         if (panning == 1) {
 643                             panning = 0;
 644                             sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate),
 645                                   event->key.time);
 646                             desktop->updateNow();
 647                         }
 648                         ret= TRUE;
 649                     }
 650                     break;
 651                 case GDK_Q:
 652                 case GDK_q:
 653                                         if (desktop->quick_zoomed()) {
 654                                                 desktop->zoom_quick(false);
 655                         ret = TRUE;
 656                     }
 657                     break;
 658                 default:
 659                     break;
 660             }
 661             break;
 662         case GDK_SCROLL:
 663         {
 664             bool ctrl = (event->scroll.state & GDK_CONTROL_MASK);
 665             bool wheelzooms = prefs->getBool("/options/wheelzooms/value");
 666             int const wheel_scroll = prefs->getIntLimited("/options/wheelscroll/value", 40, 0, 1000);
 667
 668             /* shift + wheel, pan left--right */
 669             if (event->scroll.state & GDK_SHIFT_MASK) {
 670                 switch (event->scroll.direction) {
 671                     case GDK_SCROLL_UP:
 672                         desktop->scroll_world(wheel_scroll, 0);
 673                         break;
 674                     case GDK_SCROLL_DOWN:
 675                         desktop->scroll_world(-wheel_scroll, 0);
 676                         break;
 677                     default:
 678                         break;
 679                 }
 680
 681                 /* ctrl + wheel, zoom in--out */
 682             } else if ((ctrl && !wheelzooms) || (!ctrl && wheelzooms)) {
 683                 double rel_zoom;
 684                 double const zoom_inc = prefs->getDoubleLimited("/options/zoomincrement/value", M_SQRT2, 1.01, 10);
 685                 switch (event->scroll.direction) {
 686                     case GDK_SCROLL_UP:
 687                         rel_zoom = zoom_inc;
 688                         break;
 689                     case GDK_SCROLL_DOWN:
 690                         rel_zoom = 1 / zoom_inc;
 691                         break;
 692                     default:
 693                         rel_zoom = 0.0;
 694                         break;
 695                 }
 696                 if (rel_zoom != 0.0) {
 697                     Geom::Point const scroll_dt = desktop->point();
 698                     desktop->zoom_relative_keep_point(scroll_dt, rel_zoom);
 699                 }
 700
 701                 /* no modifier, pan up--down (left--right on multiwheel mice?) */
 702             } else {
 703                 switch (event->scroll.direction) {
 704                     case GDK_SCROLL_UP:
 705                         desktop->scroll_world(0, wheel_scroll);
 706                         break;
 707                     case GDK_SCROLL_DOWN:
 708                         desktop->scroll_world(0, -wheel_scroll);
 709                         break;
 710                     case GDK_SCROLL_LEFT:
 711                         desktop->scroll_world(wheel_scroll, 0);
 712                         break;
 713                     case GDK_SCROLL_RIGHT:
 714                         desktop->scroll_world(-wheel_scroll, 0);
 715                         break;
 716                 }
 717             }
 718             break;
 719         }
 720         default:
 721             break;
 722     }
 723
 724     return ret;
 725 }
 726
 727 /**
 728  * Handles item specific events. Gets called from Gdk.
 729  *
 730  * Only reacts to right mouse button at the moment.
 731  * \todo Fixme: do context sensitive popup menu on items.
 732  */
 733 gint
 734 sp_event_context_private_item_handler(SPEventContext *ec, SPItem *item, GdkEvent *event)
 735 {
 736     int ret = FALSE;
 737
 738     switch (event->type) {
 739         case GDK_BUTTON_PRESS:
 740             if ((event->button.button == 3)
 741                     && !(event->button.state & GDK_SHIFT_MASK || event->button.state & GDK_CONTROL_MASK)) {
 742                 sp_event_root_menu_popup(ec->desktop, item, event);
 743                 ret = TRUE;
 744             }
 745             break;
 746         default:
 747             break;
 748     }
 749
 750     return ret;
 751 }
 752
 753 /**
 754  * @brief An observer that relays pref changes to the derived classes
 755  */
 756 class ToolPrefObserver : public Inkscape::Preferences::Observer {
 757 public:
 758     ToolPrefObserver(Glib::ustring const &path, SPEventContext *ec) :
 759         Inkscape::Preferences::Observer(path),
 760         _ec(ec) {}
 761     virtual void notify(Inkscape::Preferences::Entry const &val)
 762     {
 763         if (((SPEventContextClass *) G_OBJECT_GET_CLASS(_ec))->set) {
 764             ((SPEventContextClass *) G_OBJECT_GET_CLASS(_ec))->set(_ec,
 765                 const_cast<Inkscape::Preferences::Entry*>(&val));
 766         }
 767     }
 768 private:
 769     SPEventContext * const _ec;
 770 };
 771
 772 /**
 773  * Creates new SPEventContext object and calls its virtual setup() function.
 774  * @todo This is bogus. pref_path should be a private property of the inheriting objects.
 775  */
 776 SPEventContext *
 777 sp_event_context_new(GType type, SPDesktop *desktop, gchar const *pref_path, unsigned int key)
 778 {
 779     g_return_val_if_fail(g_type_is_a(type, SP_TYPE_EVENT_CONTEXT), NULL);
 780     g_return_val_if_fail(desktop != NULL, NULL);
 781
 782     SPEventContext *const ec = (SPEventContext*)g_object_new(type, NULL);
 783
 784     ec->desktop = desktop;
 785     ec->_message_context = new Inkscape::MessageContext(desktop->messageStack());
 786     ec->key = key;
 787     ec->pref_observer = NULL;
 788
 789     if (pref_path) {
 790         ec->pref_observer = new ToolPrefObserver(pref_path, ec);
 791
 792         Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 793         prefs->addObserver(*(ec->pref_observer));
 794     }
 795
 796     if (((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->setup)
 797         ((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->setup(ec);
 798
 799     return ec;
 800 }
 801
 802 /**
 803  * Finishes SPEventContext.
 804  */
 805 void
 806 sp_event_context_finish(SPEventContext *ec)
 807 {
 808     g_return_if_fail(ec != NULL);
 809     g_return_if_fail(SP_IS_EVENT_CONTEXT(ec));
 810
 811     ec->enableSelectionCue(false);
 812
 813     if (ec->next) {
 814         g_warning("Finishing event context with active link\n");
 815     }
 816
 817     if (((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->finish)
 818         ((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->finish(ec);
 819 }
 820
 821 //-------------------------------member functions
 822
 823 /**
 824  * Enables/disables the SPEventContext's SelCue.
 825  */
 826 void SPEventContext::enableSelectionCue(bool enable) {
 827     if (enable) {
 828         if (!_selcue) {
 829             _selcue = new Inkscape::SelCue(desktop);
 830         }
 831     } else {
 832         delete _selcue;
 833         _selcue = NULL;
 834     }
 835 }
 836
 837 /**
 838  * Enables/disables the SPEventContext's GrDrag.
 839  */
 840 void SPEventContext::enableGrDrag(bool enable) {
 841     if (enable) {
 842         if (!_grdrag) {
 843             _grdrag = new GrDrag(desktop);
 844         }
 845     } else {
 846         if (_grdrag) {
 847             delete _grdrag;
 848             _grdrag = NULL;
 849         }
 850     }
 851 }
 852
 853 /**
 854  * Calls virtual set() function of SPEventContext.
 855  */
 856 void
 857 sp_event_context_read(SPEventContext *ec, gchar const *key)
 858 {
 859     g_return_if_fail(ec != NULL);
 860     g_return_if_fail(SP_IS_EVENT_CONTEXT(ec));
 861     g_return_if_fail(key != NULL);
 862
 863     if (((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->set) {
 864         Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 865         Inkscape::Preferences::Entry val = prefs->getEntry(
 866             ec->pref_observer->observed_path + '/' + key );
 867         ((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->set(ec, &val);
 868     }
 869 }
 870
 871 /**
 872  * Calls virtual activate() function of SPEventContext.
 873  */
 874 void
 875 sp_event_context_activate(SPEventContext *ec)
 876 {
 877     g_return_if_fail(ec != NULL);
 878     g_return_if_fail(SP_IS_EVENT_CONTEXT(ec));
 879
 880     // Make sure no delayed snapping events are carried over after switching contexts
 881     // (this is only an additional safety measure against sloppy coding, because each
 882     // context should take care of this by itself.
 883     sp_event_context_discard_delayed_snap_event(ec);
 884
 885     if (((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->activate)
 886         ((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->activate(ec);
 887 }
 888
 889 /**
 890  * Calls virtual deactivate() function of SPEventContext.
 891  */
 892 void
 893 sp_event_context_deactivate(SPEventContext *ec)
 894 {
 895     g_return_if_fail(ec != NULL);
 896     g_return_if_fail(SP_IS_EVENT_CONTEXT(ec));
 897
 898     if (((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->deactivate)
 899         ((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->deactivate(ec);
 900 }
 901
 902 /**
 903  * Calls virtual root_handler(), the main event handling function.
 904  */
 905 gint
 906 sp_event_context_root_handler(SPEventContext * event_context, GdkEvent * event)
 907 {
 908     switch (event->type) {
 909                 case GDK_MOTION_NOTIFY:
 910                         sp_event_context_snap_delay_handler(event_context, NULL, NULL, (GdkEventMotion *)event, DelayedSnapEvent::EVENTCONTEXT_ROOT_HANDLER);
 911                         break;
 912                 case GDK_BUTTON_RELEASE:
 913                         if (event_context->_delayed_snap_event) {
 914                                 // If we have any pending snapping action, then invoke it now
 915                                 sp_event_context_snap_watchdog_callback(event_context->_delayed_snap_event);
 916                         }
 917                         break;
 918                 case GDK_BUTTON_PRESS:
 919         case GDK_2BUTTON_PRESS:
 920         case GDK_3BUTTON_PRESS:
 921                         // Snapping will be on hold if we're moving the mouse at high speeds. When starting
 922                         // drawing a new shape we really should snap though.
 923                         event_context->desktop->namedview->snap_manager.snapprefs.setSnapPostponedGlobally(false);
 924                         break;
 925         default:
 926                 break;
 927     }
 928
 929     return sp_event_context_virtual_root_handler(event_context, event);
 930 }
 931
 932 gint
 933 sp_event_context_virtual_root_handler(SPEventContext * event_context, GdkEvent * event)
 934 {
 935         gint ret = ((SPEventContextClass *) G_OBJECT_GET_CLASS(event_context))->root_handler(event_context, event);
 936         set_event_location(event_context->desktop, event);
 937         return ret;
 938 }
 939
 940 /**
 941  * Calls virtual item_handler(), the item event handling function.
 942  */
 943 gint
 944 sp_event_context_item_handler(SPEventContext * event_context, SPItem * item, GdkEvent * event)
 945 {
 946         switch (event->type) {
 947                 case GDK_MOTION_NOTIFY:
 948                         sp_event_context_snap_delay_handler(event_context, item, NULL, (GdkEventMotion *)event, DelayedSnapEvent::EVENTCONTEXT_ITEM_HANDLER);
 949                         break;
 950                 case GDK_BUTTON_RELEASE:
 951                         if (event_context->_delayed_snap_event) {
 952                                 // If we have any pending snapping action, then invoke it now
 953                                 sp_event_context_snap_watchdog_callback(event_context->_delayed_snap_event);
 954                         }
 955                         break;
 956                 /*case GDK_BUTTON_PRESS:
 957                 case GDK_2BUTTON_PRESS:
 958                 case GDK_3BUTTON_PRESS:
 959                         // Snapping will be on hold if we're moving the mouse at high speeds. When starting
 960                         // drawing a new shape we really should snap though.
 961                         event_context->desktop->namedview->snap_manager.snapprefs.setSnapPostponedGlobally(false);
 962                         break;
 963                 */
 964                 default:
 965                         break;
 966         }
 967
 968     return sp_event_context_virtual_item_handler(event_context, item, event);
 969 }
 970
 971 gint
 972 sp_event_context_virtual_item_handler(SPEventContext * event_context, SPItem * item, GdkEvent * event)
 973 {
 974         gint ret = ((SPEventContextClass *) G_OBJECT_GET_CLASS(event_context))->item_handler(event_context, item, event);
 975
 976         if (! ret) {
 977                 ret = sp_event_context_virtual_root_handler(event_context, event);
 978         } else {
 979                 set_event_location(event_context->desktop, event);
 980         }
 981
 982         return ret;
 983 }
 984
 985 /**
 986  * Emits 'position_set' signal on desktop and shows coordinates on status bar.
 987  */
 988 static void set_event_location(SPDesktop *desktop, GdkEvent *event)
 989 {
 990     if (event->type != GDK_MOTION_NOTIFY) {
 991         return;
 992     }
 993
 994     Geom::Point const button_w(event->button.x, event->button.y);
 995     Geom::Point const button_dt(desktop->w2d(button_w));
 996     desktop->setPosition(button_dt);
 997     desktop->set_coordinate_status(button_dt);
 998 }
 999
1000 //-------------------------------------------------------------------
1001 /**
1002  * Create popup menu and tell Gtk to show it.
1003  */
1004 void
1005 sp_event_root_menu_popup(SPDesktop *desktop, SPItem *item, GdkEvent *event)
1006 {
1007     GtkWidget *menu;
1008
1009     /* fixme: This is not what I want but works for now (Lauris) */
1010     if (event->type == GDK_KEY_PRESS) {
1011         item = sp_desktop_selection(desktop)->singleItem();
1012     }
1013     menu = sp_ui_context_menu(desktop, item);
1014     gtk_widget_show(menu);
1015
1016     switch (event->type) {
1017         case GDK_BUTTON_PRESS:
1018             gtk_menu_popup(GTK_MENU(menu), NULL, NULL, 0, NULL, event->button.button, event->button.time);
1019             break;
1020         case GDK_KEY_PRESS:
1021             gtk_menu_popup(GTK_MENU(menu), NULL, NULL, 0, NULL, 0, event->key.time);
1022             break;
1023         default:
1024             break;
1025     }
1026 }
1027
1028 /**
1029  * Show tool context specific modifier tip.
1030  */
1031 void
1032 sp_event_show_modifier_tip(Inkscape::MessageContext *message_context,
1033         GdkEvent *event, gchar const *ctrl_tip, gchar const *shift_tip,
1034         gchar const *alt_tip)
1035 {
1036     guint keyval = get_group0_keyval(&event->key);
1037
1038     bool ctrl = ctrl_tip && (MOD__CTRL
1039             || (keyval == GDK_Control_L)
1040             || (keyval == GDK_Control_R));
1041     bool shift = shift_tip
1042         && (MOD__SHIFT || (keyval == GDK_Shift_L) || (keyval == GDK_Shift_R));
1043     bool alt = alt_tip
1044         && (MOD__ALT
1045                 || (keyval == GDK_Alt_L)
1046                 || (keyval == GDK_Alt_R)
1047                 || (keyval == GDK_Meta_L)
1048                 || (keyval == GDK_Meta_R));
1049
1050     gchar *tip = g_strdup_printf("%s%s%s%s%s",
1051                                  ( ctrl ? ctrl_tip : "" ),
1052                                  ( ctrl && (shift || alt) ? "; " : "" ),
1053                                  ( shift ? shift_tip : "" ),
1054                                  ( (ctrl || shift) && alt ? "; " : "" ),
1055                                  ( alt ? alt_tip : "" ));
1056
1057     if (strlen(tip) > 0) {
1058         message_context->flash(Inkscape::INFORMATION_MESSAGE, tip);
1059     }
1060
1061     g_free(tip);
1062 }
1063
1064 /**
1065  * Return the keyval corresponding to the key event in group 0, i.e.,
1066  * in the main (English) layout.
1067  *
1068  * Use this instead of simply event->keyval, so that your keyboard shortcuts
1069  * work regardless of layouts (e.g., in Cyrillic).
1070  */
1071 guint
1072 get_group0_keyval(GdkEventKey *event)
1073 {
1074     guint keyval = 0;
1075     gdk_keymap_translate_keyboard_state(
1076             gdk_keymap_get_for_display(gdk_display_get_default()),
1077             event->hardware_keycode,
1078             (GdkModifierType) event->state,
1079             0   /*event->key.group*/,
1080             &keyval, NULL, NULL, NULL);
1081     return keyval;
1082 }
1083
1084 /**
1085  * Returns item at point p in desktop.
1086  *
1087  * If state includes alt key mask, cyclically selects under; honors
1088  * into_groups.
1089  */
1090 SPItem *
1091 sp_event_context_find_item (SPDesktop *desktop, Geom::Point const &p,
1092         bool select_under, bool into_groups)
1093 {
1094     SPItem *item;
1095
1096     if (select_under) {
1097         SPItem *selected_at_point =
1098             desktop->item_from_list_at_point_bottom (desktop->selection->itemList(), p);
1099         item = desktop->item_at_point(p, into_groups, selected_at_point);
1100         if (item == NULL) { // we may have reached bottom, flip over to the top
1101             item = desktop->item_at_point(p, into_groups, NULL);
1102         }
1103     } else
1104         item = desktop->item_at_point(p, into_groups, NULL);
1105
1106     return item;
1107 }
1108
1109 /**
1110  * Returns item if it is under point p in desktop, at any depth; otherwise returns NULL.
1111  *
1112  * Honors into_groups.
1113  */
1114 SPItem *
1115 sp_event_context_over_item (SPDesktop *desktop, SPItem *item, Geom::Point const &p)
1116 {
1117     GSList *temp = NULL;
1118     temp = g_slist_prepend (temp, item);
1119     SPItem *item_at_point = desktop->item_from_list_at_point_bottom (temp, p);
1120     g_slist_free (temp);
1121
1122     return item_at_point;
1123 }
1124
1125 ShapeEditor *
1126 sp_event_context_get_shape_editor (SPEventContext *ec)
1127 {
1128     return ec->shape_editor;
1129 }
1130
1131 void
1132 event_context_print_event_info(GdkEvent *event, bool print_return) {
1133     switch (event->type) {
1134         case GDK_BUTTON_PRESS:
1135             g_print ("GDK_BUTTON_PRESS");
1136             break;
1137         case GDK_2BUTTON_PRESS:
1138             g_print ("GDK_2BUTTON_PRESS");
1139             break;
1140         case GDK_3BUTTON_PRESS:
1141             g_print ("GDK_3BUTTON_PRESS");
1142             break;
1143
1144         case GDK_MOTION_NOTIFY:
1145             g_print ("GDK_MOTION_NOTIFY");
1146             break;
1147         case GDK_ENTER_NOTIFY:
1148             g_print ("GDK_ENTER_NOTIFY");
1149             break;
1150
1151         case GDK_LEAVE_NOTIFY:
1152             g_print ("GDK_LEAVE_NOTIFY");
1153             break;
1154         case GDK_BUTTON_RELEASE:
1155             g_print ("GDK_BUTTON_RELEASE");
1156             break;
1157
1158         case GDK_KEY_PRESS:
1159             g_print ("GDK_KEY_PRESS: %d", get_group0_keyval(&event->key));
1160             break;
1161         case GDK_KEY_RELEASE:
1162             g_print ("GDK_KEY_RELEASE: %d", get_group0_keyval(&event->key));
1163             break;
1164         default:
1165             //g_print ("even type not recognized");
1166             break;
1167     }
1168
1169     if (print_return) {
1170         g_print ("\n");
1171     }
1172 }
1173
1174 void sp_event_context_snap_delay_handler(SPEventContext *ec, SPItem* const item, SPKnot* const knot, GdkEventMotion *event, DelayedSnapEvent::DelayedSnapEventOrigin origin)
1175 {
1176         static guint32 prev_time;
1177         static boost::optional<Geom::Point> prev_pos;
1178
1179         // Snapping occurs when dragging with the left mouse button down, or when hovering e.g. in the pen tool with left mouse button up
1180     bool const c1 = event->state & GDK_BUTTON2_MASK; // We shouldn't hold back any events when other mouse buttons have been
1181     bool const c2 = event->state & GDK_BUTTON3_MASK; // pressed, e.g. when scrolling with the middle mouse button; if we do then
1182                                                                                                      // Inkscape will get stuck in an unresponsive state
1183     bool const c3 = tools_isactive(ec->desktop, TOOLS_CALLIGRAPHIC);
1184                                                      // The snap delay will repeat the last motion event, which will lead to
1185                                                      // erroneous points in the calligraphy context. And because we don't snap
1186                                                      // in this context, we might just as well disable the snap delay all together
1187
1188     if (c1 || c2 || c3) {
1189         // Make sure that we don't send any pending snap events to a context if we know in advance
1190         // that we're not going to snap any way (e.g. while scrolling with middle mouse button)
1191         // Any motion event might affect the state of the context, leading to unexpected behavior
1192         sp_event_context_discard_delayed_snap_event(ec);
1193     } else if (ec->desktop && ec->desktop->namedview->snap_manager.snapprefs.getSnapEnabledGlobally()) {
1194                 // Snap when speed drops below e.g. 0.02 px/msec, or when no motion events have occurred for some period.
1195                 // i.e. snap when we're at stand still. A speed threshold enforces snapping for tablets, which might never
1196                 // be fully at stand still and might keep spitting out motion events.
1197                 ec->desktop->namedview->snap_manager.snapprefs.setSnapPostponedGlobally(true); // put snapping on hold
1198
1199                 Geom::Point event_pos(event->x, event->y);
1200                 guint32 event_t = gdk_event_get_time ( (GdkEvent *) event );
1201
1202                 if (prev_pos) {
1203                         Geom::Coord dist = Geom::L2(event_pos - *prev_pos);
1204                         guint32 delta_t = event_t - prev_time;
1205                         gdouble speed = delta_t > 0 ? dist/delta_t : 1000;
1206                         //std::cout << "Mouse speed = " << speed << " px/msec " << std::endl;
1207                         if (speed > 0.02) { // Jitter threshold, might be needed for tablets
1208                                 // We're moving fast, so postpone any snapping until the next GDK_MOTION_NOTIFY event. We
1209                                 // will keep on postponing the snapping as long as the speed is high.
1210                                 // We must snap at some point in time though, so set a watchdog timer at some time from
1211                                 // now, just in case there's no future motion event that drops under the speed limit (when
1212                                 // stopping abruptly)
1213                                 delete ec->_delayed_snap_event;
1214                                 ec->_delayed_snap_event = new DelayedSnapEvent(ec, item, knot, event, origin); // watchdog is reset, i.e. pushed forward in time
1215                                 // If the watchdog expires before a new motion event is received, we will snap (as explained
1216                                 // above). This means however that when the timer is too short, we will always snap and that the
1217                                 // speed threshold is ineffective. In the extreme case the delay is set to zero, and snapping will
1218                                 // be immediate, as it used to be in the old days ;-).
1219                         } else { // Speed is very low, so we're virtually at stand still
1220                                 // But if we're really standing still, then we should snap now. We could use some low-pass filtering,
1221                                 // otherwise snapping occurs for each jitter movement. For this filtering we'll leave the watchdog to expire,
1222                                 // snap, and set a new watchdog again.
1223                                 if (ec->_delayed_snap_event == NULL) { // no watchdog has been set
1224                                         // it might have already expired, so we'll set a new one; the snapping frequency will be limited by this
1225                                         ec->_delayed_snap_event = new DelayedSnapEvent(ec, item, knot, event, origin);
1226                                 } // else: watchdog has been set before and we'll wait for it to expire
1227                         }
1228                 } else {
1229                         // This is the first GDK_MOTION_NOTIFY event, so postpone snapping and set the watchdog
1230                         g_assert(ec->_delayed_snap_event == NULL);
1231                         ec->_delayed_snap_event = new DelayedSnapEvent(ec, item, knot, event, origin);
1232                 }
1233
1234                 prev_pos = event_pos;
1235                 prev_time = event_t;
1236     }
1237 }
1238
1239 gboolean sp_event_context_snap_watchdog_callback(gpointer data)
1240 {
1241         // Snap NOW! For this the "postponed" flag will be reset and the last motion event will be repeated
1242         DelayedSnapEvent *dse = reinterpret_cast<DelayedSnapEvent*>(data);
1243
1244         if (dse == NULL) {
1245                 // This might occur when this method is called directly, i.e. not through the timer
1246                 // E.g. on GDK_BUTTON_RELEASE in sp_event_context_root_handler()
1247                 return FALSE;
1248         }
1249
1250         SPEventContext *ec = dse->getEventContext();
1251         if (ec == NULL || ec->desktop == NULL) {
1252                 return false;
1253         }
1254
1255         SPDesktop *dt = ec->desktop;
1256         dt->namedview->snap_manager.snapprefs.setSnapPostponedGlobally(false);
1257
1258         switch (dse->getOrigin()) {
1259                 case DelayedSnapEvent::EVENTCONTEXT_ROOT_HANDLER:
1260                         sp_event_context_virtual_root_handler(ec, dse->getEvent());
1261                         break;
1262                 case DelayedSnapEvent::EVENTCONTEXT_ITEM_HANDLER:
1263                         {
1264                                 SPItem* item = NULL;
1265                                 item = dse->getItem();
1266                                 if (item && SP_IS_ITEM(item)) {
1267                                         sp_event_context_virtual_item_handler(ec, item, dse->getEvent());
1268                                 }
1269                         }
1270                         break;
1271                 case DelayedSnapEvent::KNOT_HANDLER:
1272                         {
1273                                 SPKnot* knot = dse->getKnot();
1274                                 if (knot && SP_IS_KNOT(knot)) {
1275                                         sp_knot_handler_request_position(dse->getEvent(), knot);
1276                                 }
1277                         }
1278                         break;
1279                 default:
1280                         g_warning("Origin of snap-delay event has not been defined!;");
1281                         break;
1282         }
1283
1284         ec->_delayed_snap_event = NULL;
1285         delete dse;
1286
1287         return FALSE; //Kills the timer and stops it from executing this callback over and over again.
1288 }
1289
1290 void sp_event_context_discard_delayed_snap_event(SPEventContext *ec)
1291 {
1292         delete ec->_delayed_snap_event;
1293         ec->_delayed_snap_event = NULL;
1294 }
1295
1296
1297
1298 /*
1299   Local Variables:
1300   mode:c++
1301   c-file-style:"stroustrup"
1302   c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
1303   indent-tabs-mode:nil
1304   fill-column:99
1305   End:
1306 */
1307 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :