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 "node-context.h"
  60 #include "lpe-tool-context.h"
  61
  62 static void sp_event_context_class_init(SPEventContextClass *klass);
  63 static void sp_event_context_init(SPEventContext *event_context);
  64 static void sp_event_context_dispose(GObject *object);
  65
  66 static void sp_event_context_private_setup(SPEventContext *ec);
  67 static gint sp_event_context_private_root_handler(SPEventContext *event_context, GdkEvent *event);
  68 static gint sp_event_context_private_item_handler(SPEventContext *event_context, SPItem *item, GdkEvent *event);
  69
  70 static void set_event_location(SPDesktop * desktop, GdkEvent * event);
  71
  72 static GObjectClass *parent_class;
  73
  74 // globals for temporary switching to selector by space
  75 static bool selector_toggled = FALSE;
  76 static int switch_selector_to = 0;
  77
  78 // globals for temporary switching to dropper by 'D'
  79 static bool dropper_toggled = FALSE;
  80 static int switch_dropper_to = 0;
  81
  82 static gint xp = 0, yp = 0; // where drag started
  83 static gint tolerance = 0;
  84 static bool within_tolerance = false;
  85
  86 // globals for keeping track of keyboard scroll events in order to accelerate
  87 static guint32 scroll_event_time = 0;
  88 static gdouble scroll_multiply = 1;
  89 static guint scroll_keyval = 0;
  90
  91 /**
  92  * Registers the SPEventContext class with Glib and returns its type number.
  93  */
  94 GType
  95 sp_event_context_get_type(void)
  96 {
  97     static GType type = 0;
  98     if (!type) {
  99         GTypeInfo info = {
 100             sizeof(SPEventContextClass),
 101             NULL, NULL,
 102             (GClassInitFunc) sp_event_context_class_init,
 103             NULL, NULL,
 104             sizeof(SPEventContext),
 105             4,
 106             (GInstanceInitFunc) sp_event_context_init,
 107             NULL,    /* value_table */
 108         };
 109         type = g_type_register_static(G_TYPE_OBJECT, "SPEventContext", &info, (GTypeFlags)0);
 110     }
 111     return type;
 112 }
 113
 114 /**
 115  * Callback to set up the SPEventContext vtable.
 116  */
 117 static void
 118 sp_event_context_class_init(SPEventContextClass *klass)
 119 {
 120     GObjectClass *object_class;
 121
 122     object_class = (GObjectClass *) klass;
 123
 124     parent_class = (GObjectClass*)g_type_class_peek_parent(klass);
 125
 126     object_class->dispose = sp_event_context_dispose;
 127
 128     klass->setup = sp_event_context_private_setup;
 129     klass->root_handler = sp_event_context_private_root_handler;
 130     klass->item_handler = sp_event_context_private_item_handler;
 131 }
 132
 133 /**
 134  * Clears all SPEventContext object members.
 135  */
 136 static void
 137 sp_event_context_init(SPEventContext *event_context)
 138 {
 139     event_context->desktop = NULL;
 140     event_context->cursor = NULL;
 141     event_context->_message_context = NULL;
 142     event_context->_selcue = NULL;
 143     event_context->_grdrag = NULL;
 144     event_context->space_panning = false;
 145     event_context->shape_editor = NULL;
 146     event_context->_delayed_snap_event = NULL;
 147 }
 148
 149 /**
 150  * Callback to free and null member variables of SPEventContext object.
 151  */
 152 static void
 153 sp_event_context_dispose(GObject *object)
 154 {
 155     SPEventContext *ec;
 156
 157     ec = SP_EVENT_CONTEXT(object);
 158
 159     if (ec->_message_context) {
 160         delete ec->_message_context;
 161     }
 162
 163     if (ec->cursor != NULL) {
 164         gdk_cursor_unref(ec->cursor);
 165         ec->cursor = NULL;
 166     }
 167
 168     if (ec->desktop) {
 169         ec->desktop = NULL;
 170     }
 171
 172     if (ec->pref_observer) {
 173         delete ec->pref_observer;
 174     }
 175
 176     if (ec->_delayed_snap_event) {
 177         delete ec->_delayed_snap_event;
 178     }
 179
 180     G_OBJECT_CLASS(parent_class)->dispose(object);
 181 }
 182
 183 /**
 184  * Recreates and draws cursor on desktop related to SPEventContext.
 185  */
 186 void
 187 sp_event_context_update_cursor(SPEventContext *ec)
 188 {
 189     GtkWidget *w = GTK_WIDGET(sp_desktop_canvas(ec->desktop));
 190     if (w->window) {
 191         /* fixme: */
 192         if (ec->cursor_shape) {
 193             GdkBitmap *bitmap = NULL;
 194             GdkBitmap *mask = NULL;
 195             sp_cursor_bitmap_and_mask_from_xpm(&bitmap, &mask, ec->cursor_shape);
 196             if ((bitmap != NULL) && (mask != NULL)) {
 197                 if (ec->cursor)
 198                     gdk_cursor_unref (ec->cursor);
 199                 ec->cursor = gdk_cursor_new_from_pixmap(bitmap, mask,
 200                                                         &w->style->black,
 201                                                         &w->style->white,
 202                                                         ec->hot_x, ec->hot_y);
 203                 g_object_unref (bitmap);
 204                 g_object_unref (mask);
 205             }
 206         }
 207         gdk_window_set_cursor(w->window, ec->cursor);
 208         gdk_flush();
 209     }
 210     ec->desktop->waiting_cursor = false;
 211 }
 212
 213 /**
 214  * Callback that gets called on initialization of SPEventContext object.
 215  * Redraws mouse cursor, at the moment.
 216  */
 217 static void
 218 sp_event_context_private_setup(SPEventContext *ec)
 219 {
 220     sp_event_context_update_cursor(ec);
 221 }
 222
 223 /**
 224  * \brief   Gobbles next key events on the queue with the same keyval and mask. Returns the number of events consumed.
 225  */
 226 gint gobble_key_events(guint keyval, gint mask)
 227 {
 228     GdkEvent *event_next;
 229     gint i = 0;
 230
 231     event_next = gdk_event_get();
 232     // while the next event is also a key notify with the same keyval and mask,
 233     while (event_next && (event_next->type == GDK_KEY_PRESS || event_next->type == GDK_KEY_RELEASE)
 234            && event_next->key.keyval == keyval
 235            && (!mask || (event_next->key.state & mask))) {
 236         if (event_next->type == GDK_KEY_PRESS)
 237             i ++;
 238         // kill it
 239         gdk_event_free(event_next);
 240         // get next
 241         event_next = gdk_event_get();
 242     }
 243     // otherwise, put it back onto the queue
 244     if (event_next) gdk_event_put(event_next);
 245
 246     return i;
 247 }
 248
 249 /**
 250  * \brief   Gobbles next motion notify events on the queue with the same mask. Returns the number of events consumed.
 251 */
 252 gint gobble_motion_events(gint mask)
 253 {
 254     GdkEvent *event_next;
 255     gint i = 0;
 256
 257     event_next = gdk_event_get();
 258     // while the next event is also a key notify with the same keyval and mask,
 259     while (event_next && event_next->type == GDK_MOTION_NOTIFY
 260            && (event_next->motion.state & mask)) {
 261         // kill it
 262         gdk_event_free(event_next);
 263         // get next
 264         event_next = gdk_event_get();
 265         i ++;
 266     }
 267     // otherwise, put it back onto the queue
 268     if (event_next) gdk_event_put(event_next);
 269
 270     return i;
 271 }
 272
 273 /**
 274  * Toggles current tool between active tool and selector tool.
 275  * Subroutine of sp_event_context_private_root_handler().
 276  */
 277 static void
 278 sp_toggle_selector(SPDesktop *dt)
 279 {
 280     if (!dt->event_context) return;
 281
 282     if (tools_isactive(dt, TOOLS_SELECT)) {
 283         if (selector_toggled) {
 284             if (switch_selector_to) tools_switch (dt, switch_selector_to);
 285             selector_toggled = FALSE;
 286         } else return;
 287     } else {
 288         selector_toggled = TRUE;
 289         switch_selector_to = tools_active(dt);
 290         tools_switch (dt, TOOLS_SELECT);
 291     }
 292 }
 293
 294 /**
 295  * Toggles current tool between active tool and dropper tool.
 296  * Subroutine of sp_event_context_private_root_handler().
 297  */
 298 static void
 299 sp_toggle_dropper(SPDesktop *dt)
 300 {
 301     if (!dt->event_context) return;
 302
 303     if (tools_isactive(dt, TOOLS_DROPPER)) {
 304         if (dropper_toggled) {
 305             if (switch_dropper_to) tools_switch (dt, switch_dropper_to);
 306             dropper_toggled = FALSE;
 307         } else return;
 308     } else {
 309         dropper_toggled = TRUE;
 310         switch_dropper_to = tools_active(dt);
 311         tools_switch (dt, TOOLS_DROPPER);
 312     }
 313 }
 314
 315 /**
 316  * Calculates and keeps track of scroll acceleration.
 317  * Subroutine of sp_event_context_private_root_handler().
 318  */
 319 static gdouble accelerate_scroll(GdkEvent *event, gdouble acceleration, SPCanvas */*canvas*/)
 320 {
 321     guint32 time_diff = ((GdkEventKey *) event)->time - scroll_event_time;
 322
 323     /* key pressed within 500ms ? (1/2 second) */
 324     if (time_diff > 500 || event->key.keyval != scroll_keyval) {
 325         scroll_multiply = 1; // abort acceleration
 326     } else {
 327         scroll_multiply += acceleration; // continue acceleration
 328     }
 329
 330     scroll_event_time = ((GdkEventKey *) event)->time;
 331     scroll_keyval = event->key.keyval;
 332
 333     return scroll_multiply;
 334 }
 335
 336 /**
 337  * Main event dispatch, gets called from Gdk.
 338  */
 339 static gint sp_event_context_private_root_handler(SPEventContext *event_context, GdkEvent *event)
 340 {
 341     static Geom::Point button_w;
 342     static unsigned int panning = 0;
 343     static unsigned int zoom_rb = 0;
 344
 345     SPDesktop *desktop = event_context->desktop;
 346     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 347
 348     /// @todo REmove redundant /value in preference keys
 349     tolerance = prefs->getIntLimited(
 350             "/options/dragtolerance/value", 0, 0, 100);
 351
 352     gint ret = FALSE;
 353
 354     switch (event->type) {
 355         case GDK_2BUTTON_PRESS:
 356             if (panning) {
 357                 panning = 0;
 358                 sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate),
 359                         event->button.time);
 360                 ret = TRUE;
 361             } else {
 362                 /* sp_desktop_dialog(); */
 363             }
 364             break;
 365         case GDK_BUTTON_PRESS:
 366
 367             // save drag origin
 368             xp = (gint) event->button.x;
 369             yp = (gint) event->button.y;
 370             within_tolerance = true;
 371
 372             button_w = Geom::Point(event->button.x, event->button.y);
 373
 374             switch (event->button.button) {
 375                 case 1:
 376                     if (event_context->space_panning) {
 377                         panning = 1;
 378                         sp_canvas_item_grab(SP_CANVAS_ITEM(desktop->acetate),
 379                             GDK_KEY_RELEASE_MASK | GDK_BUTTON_RELEASE_MASK | GDK_POINTER_MOTION_MASK | GDK_POINTER_MOTION_HINT_MASK,
 380                             NULL, event->button.time-1);
 381                         ret = TRUE;
 382                     }
 383                     break;
 384                 case 2:
 385                     if (event->button.state == GDK_SHIFT_MASK) {
 386                         zoom_rb = 2;
 387                     } else {
 388                         panning = 2;
 389                         sp_canvas_item_grab(SP_CANVAS_ITEM(desktop->acetate),
 390                             GDK_BUTTON_RELEASE_MASK | GDK_POINTER_MOTION_MASK | GDK_POINTER_MOTION_HINT_MASK,
 391                             NULL, event->button.time-1);
 392                     }
 393                     ret = TRUE;
 394                     break;
 395                 case 3:
 396                     if (event->button.state & GDK_SHIFT_MASK
 397                             || event->button.state & GDK_CONTROL_MASK) {
 398                         panning = 3;
 399                         sp_canvas_item_grab(SP_CANVAS_ITEM(desktop->acetate),
 400                                 GDK_BUTTON_RELEASE_MASK | GDK_POINTER_MOTION_MASK | GDK_POINTER_MOTION_HINT_MASK,
 401                                 NULL, event->button.time);
 402                         ret = TRUE;
 403                     } else {
 404                         sp_event_root_menu_popup(desktop, NULL, event);
 405                     }
 406                     break;
 407                 default:
 408                     break;
 409             }
 410             break;
 411         case GDK_MOTION_NOTIFY:
 412             if (panning) {
 413                 if ((panning == 2 && !(event->motion.state & GDK_BUTTON2_MASK))
 414                         || (panning == 1 && !(event->motion.state & GDK_BUTTON1_MASK))
 415                         || (panning == 3 && !(event->motion.state & GDK_BUTTON3_MASK))
 416                    ) {
 417                     /* Gdk seems to lose button release for us sometimes :-( */
 418                     panning = 0;
 419                     sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate),
 420                             event->button.time);
 421                     ret = TRUE;
 422                 } else {
 423                     if ( within_tolerance
 424                          && ( abs( (gint) event->motion.x - xp ) < tolerance )
 425                          && ( abs( (gint) event->motion.y - yp ) < tolerance ))
 426                     {
 427                         // do not drag if we're within tolerance from origin
 428                         break;
 429                     }
 430                     // Once the user has moved farther than tolerance from
 431                     // the original location (indicating they intend to move
 432                     // the object, not click), then always process the motion
 433                     // notify coordinates as given (no snapping back to origin)
 434                     within_tolerance = false;
 435
 436                     // gobble subsequent motion events to prevent "sticking"
 437                     // when scrolling is slow
 438                     gobble_motion_events(panning == 2 ?
 439                                          GDK_BUTTON2_MASK :
 440                                          (panning == 1 ? GDK_BUTTON1_MASK : GDK_BUTTON3_MASK));
 441
 442                     Geom::Point const motion_w(event->motion.x, event->motion.y);
 443                     Geom::Point const moved_w( motion_w - button_w );
 444                     event_context->desktop->scroll_world(moved_w, true); // we're still scrolling, do not redraw
 445                     ret = TRUE;
 446                 }
 447             } else if (zoom_rb) {
 448                 Geom::Point const motion_w(event->motion.x, event->motion.y);
 449                 Geom::Point const motion_dt(desktop->w2d(motion_w));
 450
 451                 if ( within_tolerance
 452                      && ( abs( (gint) event->motion.x - xp ) < tolerance )
 453                      && ( abs( (gint) event->motion.y - yp ) < tolerance ) ) {
 454                     break; // do not drag if we're within tolerance from origin
 455                 }
 456                 // Once the user has moved farther than tolerance from the original location
 457                 // (indicating they intend to move the object, not click), then always process the
 458                 // motion notify coordinates as given (no snapping back to origin)
 459                 within_tolerance = false;
 460
 461                 if (Inkscape::Rubberband::get(desktop)->is_started()) {
 462                     Inkscape::Rubberband::get(desktop)->move(motion_dt);
 463                 } else {
 464                     Inkscape::Rubberband::get(desktop)->start(desktop, motion_dt);
 465                 }
 466                 if (zoom_rb == 2)
 467                     gobble_motion_events(GDK_BUTTON2_MASK);
 468             }
 469             break;
 470         case GDK_BUTTON_RELEASE:
 471             xp = yp = 0;
 472             if (within_tolerance && (panning || zoom_rb)) {
 473                 zoom_rb = 0;
 474                 if (panning) {
 475                     panning = 0;
 476                     sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate),
 477                                       event->button.time);
 478                 }
 479                 Geom::Point const event_w(event->button.x, event->button.y);
 480                 Geom::Point const event_dt(desktop->w2d(event_w));
 481                 double const zoom_inc = prefs->getDoubleLimited("/options/zoomincrement/value", M_SQRT2, 1.01, 10);
 482                 desktop->zoom_relative_keep_point(event_dt,
 483                           (event->button.state & GDK_SHIFT_MASK) ? 1/zoom_inc : zoom_inc);
 484                 desktop->updateNow();
 485                 ret = TRUE;
 486             } else if (panning == event->button.button) {
 487                 panning = 0;
 488                 sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate),
 489                                       event->button.time);
 490
 491                 // in slow complex drawings, some of the motion events are lost;
 492                 // to make up for this, we scroll it once again to the button-up event coordinates
 493                 // (i.e. canvas will always get scrolled all the way to the mouse release point,
 494                 // even if few intermediate steps were visible)
 495                 Geom::Point const motion_w(event->button.x, event->button.y);
 496                 Geom::Point const moved_w( motion_w - button_w );
 497                 event_context->desktop->scroll_world(moved_w);
 498                 desktop->updateNow();
 499                 ret = TRUE;
 500             } else if (zoom_rb == event->button.button) {
 501                 zoom_rb = 0;
 502                 Geom::OptRect const b = Inkscape::Rubberband::get(desktop)->getRectangle();
 503                 Inkscape::Rubberband::get(desktop)->stop();
 504                 if (b && !within_tolerance) {
 505                     desktop->set_display_area(*b, 10);
 506                 }
 507                 ret = TRUE;
 508             }
 509             break;
 510         case GDK_KEY_PRESS:
 511                 {
 512                 double const acceleration = prefs->getDoubleLimited("/options/scrollingacceleration/value", 0, 0, 6);
 513                 int const key_scroll = prefs->getIntLimited("/options/keyscroll/value", 10, 0, 1000);
 514
 515                 switch (get_group0_keyval(&event->key)) {
 516                 // GDK insists on stealing these keys (F1 for no idea what, tab for cycling widgets
 517                 // in the editing window). So we resteal them back and run our regular shortcut
 518                 // invoker on them.
 519                 unsigned int shortcut;
 520                 case GDK_Tab:
 521                 case GDK_ISO_Left_Tab:
 522                 case GDK_F1:
 523                     shortcut = get_group0_keyval(&event->key);
 524                     if (event->key.state & GDK_SHIFT_MASK)
 525                         shortcut |= SP_SHORTCUT_SHIFT_MASK;
 526                     if (event->key.state & GDK_CONTROL_MASK)
 527                         shortcut |= SP_SHORTCUT_CONTROL_MASK;
 528                     if (event->key.state & GDK_MOD1_MASK)
 529                         shortcut |= SP_SHORTCUT_ALT_MASK;
 530                     ret = sp_shortcut_invoke(shortcut, desktop);
 531                     break;
 532
 533                 case GDK_D:
 534                 case GDK_d:
 535                     if (!MOD__SHIFT && !MOD__CTRL && !MOD__ALT) {
 536                         sp_toggle_dropper(desktop);
 537                         ret = TRUE;
 538                     }
 539                     break;
 540                 case GDK_Q:
 541                 case GDK_q:
 542                                         if (desktop->quick_zoomed()) {
 543                                                 ret = TRUE;
 544                                         }
 545                     if (!MOD__SHIFT && !MOD__CTRL && !MOD__ALT) {
 546                                                 desktop->zoom_quick(true);
 547                         ret = TRUE;
 548                     }
 549                     break;
 550                 case GDK_W:
 551                 case GDK_w:
 552                 case GDK_F4:
 553                     /* Close view */
 554                     if (MOD__CTRL_ONLY) {
 555                         sp_ui_close_view(NULL);
 556                         ret = TRUE;
 557                     }
 558                     break;
 559                 case GDK_Left: // Ctrl Left
 560                 case GDK_KP_Left:
 561                 case GDK_KP_4:
 562                     if (MOD__CTRL_ONLY) {
 563                         int i = (int) floor(key_scroll * accelerate_scroll(event, acceleration, sp_desktop_canvas(desktop)));
 564                         gobble_key_events(get_group0_keyval(&event->key),
 565                                 GDK_CONTROL_MASK);
 566                         event_context->desktop->scroll_world(i, 0);
 567                         ret = TRUE;
 568                     }
 569                     break;
 570                 case GDK_Up: // Ctrl Up
 571                 case GDK_KP_Up:
 572                 case GDK_KP_8:
 573                     if (MOD__CTRL_ONLY) {
 574                         int i = (int) floor(key_scroll * accelerate_scroll(event, acceleration, sp_desktop_canvas(desktop)));
 575                         gobble_key_events(get_group0_keyval(&event->key),
 576                                 GDK_CONTROL_MASK);
 577                         event_context->desktop->scroll_world(0, i);
 578                         ret = TRUE;
 579                     }
 580                     break;
 581                 case GDK_Right: // Ctrl Right
 582                 case GDK_KP_Right:
 583                 case GDK_KP_6:
 584                     if (MOD__CTRL_ONLY) {
 585                         int i = (int) floor(key_scroll * accelerate_scroll(event, acceleration, sp_desktop_canvas(desktop)));
 586                         gobble_key_events(get_group0_keyval(&event->key),
 587                                 GDK_CONTROL_MASK);
 588                         event_context->desktop->scroll_world(-i, 0);
 589                         ret = TRUE;
 590                     }
 591                     break;
 592                 case GDK_Down: // Ctrl Down
 593                 case GDK_KP_Down:
 594                 case GDK_KP_2:
 595                     if (MOD__CTRL_ONLY) {
 596                         int i = (int) floor(key_scroll * accelerate_scroll(event, acceleration, sp_desktop_canvas(desktop)));
 597                         gobble_key_events(get_group0_keyval(&event->key),
 598                                 GDK_CONTROL_MASK);
 599                         event_context->desktop->scroll_world(0, -i);
 600                         ret = TRUE;
 601                     }
 602                     break;
 603                 case GDK_F10:
 604                     if (MOD__SHIFT_ONLY) {
 605                         sp_event_root_menu_popup(desktop, NULL, event);
 606                         ret= TRUE;
 607                     }
 608                     break;
 609                 case GDK_space:
 610                     if (prefs->getBool("/options/spacepans/value")) {
 611                         event_context->space_panning = true;
 612                         event_context->_message_context->set(Inkscape::INFORMATION_MESSAGE, _("<b>Space+mouse drag</b> to pan canvas"));
 613                         ret= TRUE;
 614                     } else {
 615                         sp_toggle_selector(desktop);
 616                         ret= TRUE;
 617                     }
 618                     break;
 619                 case GDK_z:
 620                 case GDK_Z:
 621                     if (MOD__ALT_ONLY) {
 622                         desktop->zoom_grab_focus();
 623                         ret = TRUE;
 624                     }
 625                     break;
 626                 default:
 627                     break;
 628             }
 629                 }
 630             break;
 631         case GDK_KEY_RELEASE:
 632             switch (get_group0_keyval(&event->key)) {
 633                 case GDK_space:
 634                     if (event_context->space_panning) {
 635                         event_context->space_panning = false;
 636                         event_context->_message_context->clear();
 637                         if (panning == 1) {
 638                             panning = 0;
 639                             sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate),
 640                                   event->key.time);
 641                             desktop->updateNow();
 642                         }
 643                         ret= TRUE;
 644                     }
 645                     break;
 646                 case GDK_Q:
 647                 case GDK_q:
 648                                         if (desktop->quick_zoomed()) {
 649                                                 desktop->zoom_quick(false);
 650                         ret = TRUE;
 651                     }
 652                     break;
 653                 default:
 654                     break;
 655             }
 656             break;
 657         case GDK_SCROLL:
 658         {
 659             bool ctrl = (event->scroll.state & GDK_CONTROL_MASK);
 660             bool wheelzooms = prefs->getBool("/options/wheelzooms/value");
 661             int const wheel_scroll = prefs->getIntLimited("/options/wheelscroll/value", 40, 0, 1000);
 662
 663             /* shift + wheel, pan left--right */
 664             if (event->scroll.state & GDK_SHIFT_MASK) {
 665                 switch (event->scroll.direction) {
 666                     case GDK_SCROLL_UP:
 667                         desktop->scroll_world(wheel_scroll, 0);
 668                         break;
 669                     case GDK_SCROLL_DOWN:
 670                         desktop->scroll_world(-wheel_scroll, 0);
 671                         break;
 672                     default:
 673                         break;
 674                 }
 675
 676                 /* ctrl + wheel, zoom in--out */
 677             } else if ((ctrl && !wheelzooms) || (!ctrl && wheelzooms)) {
 678                 double rel_zoom;
 679                 double const zoom_inc = prefs->getDoubleLimited("/options/zoomincrement/value", M_SQRT2, 1.01, 10);
 680                 switch (event->scroll.direction) {
 681                     case GDK_SCROLL_UP:
 682                         rel_zoom = zoom_inc;
 683                         break;
 684                     case GDK_SCROLL_DOWN:
 685                         rel_zoom = 1 / zoom_inc;
 686                         break;
 687                     default:
 688                         rel_zoom = 0.0;
 689                         break;
 690                 }
 691                 if (rel_zoom != 0.0) {
 692                     Geom::Point const scroll_dt = desktop->point();
 693                     desktop->zoom_relative_keep_point(scroll_dt, rel_zoom);
 694                 }
 695
 696                 /* no modifier, pan up--down (left--right on multiwheel mice?) */
 697             } else {
 698                 switch (event->scroll.direction) {
 699                     case GDK_SCROLL_UP:
 700                         desktop->scroll_world(0, wheel_scroll);
 701                         break;
 702                     case GDK_SCROLL_DOWN:
 703                         desktop->scroll_world(0, -wheel_scroll);
 704                         break;
 705                     case GDK_SCROLL_LEFT:
 706                         desktop->scroll_world(wheel_scroll, 0);
 707                         break;
 708                     case GDK_SCROLL_RIGHT:
 709                         desktop->scroll_world(-wheel_scroll, 0);
 710                         break;
 711                 }
 712             }
 713             break;
 714         }
 715         default:
 716             break;
 717     }
 718
 719     return ret;
 720 }
 721
 722 /**
 723  * Handles item specific events. Gets called from Gdk.
 724  *
 725  * Only reacts to right mouse button at the moment.
 726  * \todo Fixme: do context sensitive popup menu on items.
 727  */
 728 gint
 729 sp_event_context_private_item_handler(SPEventContext *ec, SPItem *item, GdkEvent *event)
 730 {
 731     int ret = FALSE;
 732
 733     switch (event->type) {
 734         case GDK_BUTTON_PRESS:
 735             if ((event->button.button == 3)
 736                     && !(event->button.state & GDK_SHIFT_MASK || event->button.state & GDK_CONTROL_MASK)) {
 737                 sp_event_root_menu_popup(ec->desktop, item, event);
 738                 ret = TRUE;
 739             }
 740             break;
 741         default:
 742             break;
 743     }
 744
 745     return ret;
 746 }
 747
 748 /**
 749  * @brief An observer that relays pref changes to the derived classes
 750  */
 751 class ToolPrefObserver : public Inkscape::Preferences::Observer {
 752 public:
 753     ToolPrefObserver(Glib::ustring const &path, SPEventContext *ec) :
 754         Inkscape::Preferences::Observer(path),
 755         _ec(ec) {}
 756     virtual void notify(Inkscape::Preferences::Entry const &val)
 757     {
 758         if (((SPEventContextClass *) G_OBJECT_GET_CLASS(_ec))->set) {
 759             ((SPEventContextClass *) G_OBJECT_GET_CLASS(_ec))->set(_ec,
 760                 const_cast<Inkscape::Preferences::Entry*>(&val));
 761         }
 762     }
 763 private:
 764     SPEventContext * const _ec;
 765 };
 766
 767 /**
 768  * Creates new SPEventContext object and calls its virtual setup() function.
 769  * @todo This is bogus. pref_path should be a private property of the inheriting objects.
 770  */
 771 SPEventContext *
 772 sp_event_context_new(GType type, SPDesktop *desktop, gchar const *pref_path, unsigned int key)
 773 {
 774     g_return_val_if_fail(g_type_is_a(type, SP_TYPE_EVENT_CONTEXT), NULL);
 775     g_return_val_if_fail(desktop != NULL, NULL);
 776
 777     SPEventContext *const ec = (SPEventContext*)g_object_new(type, NULL);
 778
 779     ec->desktop = desktop;
 780     ec->_message_context = new Inkscape::MessageContext(desktop->messageStack());
 781     ec->key = key;
 782     ec->pref_observer = NULL;
 783
 784     if (pref_path) {
 785         ec->pref_observer = new ToolPrefObserver(pref_path, ec);
 786
 787         Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 788         prefs->addObserver(*(ec->pref_observer));
 789     }
 790
 791     if (((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->setup)
 792         ((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->setup(ec);
 793
 794     return ec;
 795 }
 796
 797 /**
 798  * Finishes SPEventContext.
 799  */
 800 void
 801 sp_event_context_finish(SPEventContext *ec)
 802 {
 803     g_return_if_fail(ec != NULL);
 804     g_return_if_fail(SP_IS_EVENT_CONTEXT(ec));
 805
 806     ec->enableSelectionCue(false);
 807
 808     if (ec->next) {
 809         g_warning("Finishing event context with active link\n");
 810     }
 811
 812     if (((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->finish)
 813         ((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->finish(ec);
 814 }
 815
 816 //-------------------------------member functions
 817
 818 /**
 819  * Enables/disables the SPEventContext's SelCue.
 820  */
 821 void SPEventContext::enableSelectionCue(bool enable) {
 822     if (enable) {
 823         if (!_selcue) {
 824             _selcue = new Inkscape::SelCue(desktop);
 825         }
 826     } else {
 827         delete _selcue;
 828         _selcue = NULL;
 829     }
 830 }
 831
 832 /**
 833  * Enables/disables the SPEventContext's GrDrag.
 834  */
 835 void SPEventContext::enableGrDrag(bool enable) {
 836     if (enable) {
 837         if (!_grdrag) {
 838             _grdrag = new GrDrag(desktop);
 839         }
 840     } else {
 841         if (_grdrag) {
 842             delete _grdrag;
 843             _grdrag = NULL;
 844         }
 845     }
 846 }
 847
 848 /**
 849  * Calls virtual set() function of SPEventContext.
 850  */
 851 void
 852 sp_event_context_read(SPEventContext *ec, gchar const *key)
 853 {
 854     g_return_if_fail(ec != NULL);
 855     g_return_if_fail(SP_IS_EVENT_CONTEXT(ec));
 856     g_return_if_fail(key != NULL);
 857
 858     if (((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->set) {
 859         Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 860         Inkscape::Preferences::Entry val = prefs->getEntry(
 861             ec->pref_observer->observed_path + '/' + key );
 862         ((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->set(ec, &val);
 863     }
 864 }
 865
 866 /**
 867  * Calls virtual activate() function of SPEventContext.
 868  */
 869 void
 870 sp_event_context_activate(SPEventContext *ec)
 871 {
 872     g_return_if_fail(ec != NULL);
 873     g_return_if_fail(SP_IS_EVENT_CONTEXT(ec));
 874
 875     // Make sure no delayed snapping events are carried over after switching contexts
 876     // (this is only an additional safety measure against sloppy coding, because each
 877     // context should take care of this by itself. It might be hard to get each and every
 878     // context perfect though)
 879     sp_event_context_snap_window_closed(ec, false);
 880
 881     if (((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->activate)
 882         ((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->activate(ec);
 883 }
 884
 885 /**
 886  * Calls virtual deactivate() function of SPEventContext.
 887  */
 888 void
 889 sp_event_context_deactivate(SPEventContext *ec)
 890 {
 891     g_return_if_fail(ec != NULL);
 892     g_return_if_fail(SP_IS_EVENT_CONTEXT(ec));
 893
 894     if (((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->deactivate)
 895         ((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->deactivate(ec);
 896 }
 897
 898 /**
 899  * Calls virtual root_handler(), the main event handling function.
 900  */
 901 gint
 902 sp_event_context_root_handler(SPEventContext * event_context, GdkEvent * event)
 903 {
 904     //std::cout << "sp_event_context_root_handler" << std::endl;
 905         switch (event->type) {
 906                 case GDK_MOTION_NOTIFY:
 907                         sp_event_context_snap_delay_handler(event_context, NULL, NULL, (GdkEventMotion *)event, DelayedSnapEvent::EVENTCONTEXT_ROOT_HANDLER);
 908                         break;
 909                 case GDK_BUTTON_RELEASE:
 910                         if (event_context->_delayed_snap_event) {
 911                                 // If we have any pending snapping action, then invoke it now
 912                                 sp_event_context_snap_watchdog_callback(event_context->_delayed_snap_event);
 913                         }
 914                         break;
 915                 case GDK_BUTTON_PRESS:
 916         case GDK_2BUTTON_PRESS:
 917         case GDK_3BUTTON_PRESS:
 918                         // Snapping will be on hold if we're moving the mouse at high speeds. When starting
 919                         // drawing a new shape we really should snap though.
 920                         event_context->desktop->namedview->snap_manager.snapprefs.setSnapPostponedGlobally(false);
 921                         break;
 922         default:
 923                 break;
 924     }
 925
 926     return sp_event_context_virtual_root_handler(event_context, event);
 927 }
 928
 929 gint
 930 sp_event_context_virtual_root_handler(SPEventContext * event_context, GdkEvent * event)
 931 {
 932         //std::cout << "sp_event_context_virtual_root_handler -> postponed: " << event_context->desktop->namedview->snap_manager.snapprefs.getSnapPostponedGlobally() << std::endl;
 933
 934         gint ret = ((SPEventContextClass *) G_OBJECT_GET_CLASS(event_context))->root_handler(event_context, event);
 935         set_event_location(event_context->desktop, event);
 936         return ret;
 937 }
 938
 939 /**
 940  * Calls virtual item_handler(), the item event handling function.
 941  */
 942 gint
 943 sp_event_context_item_handler(SPEventContext * event_context, SPItem * item, GdkEvent * event)
 944 {
 945         //std::cout << "sp_event_context_item_handler" << std::endl;
 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
1184     if (c1 || c2) {
1185         // Make sure that we don't send any pending snap events to a context if we know in advance
1186         // that we're not going to snap any way (e.g. while scrolling with middle mouse button)
1187         // Any motion event might affect the state of the context, leading to unexpected behavior
1188         delete ec->_delayed_snap_event;
1189         ec->_delayed_snap_event = NULL;
1190     }
1191
1192     if (ec->_snap_window_open && !c1 && !c2 && ec->desktop && ec->desktop->namedview->snap_manager.snapprefs.getSnapEnabledGlobally()) {
1193         // Snap when speed drops below e.g. 0.02 px/msec, or when no motion events have occurred for some period.
1194                 // i.e. snap when we're at stand still. A speed threshold enforces snapping for tablets, which might never
1195                 // be fully at stand still and might keep spitting out motion events.
1196         ec->desktop->namedview->snap_manager.snapprefs.setSnapPostponedGlobally(true); // put snapping on hold
1197
1198         Geom::Point event_pos(event->x, event->y);
1199                 guint32 event_t = gdk_event_get_time ( (GdkEvent *) event );
1200
1201                 if (prev_pos) {
1202                         Geom::Coord dist = Geom::L2(event_pos - *prev_pos);
1203                         guint32 delta_t = event_t - prev_time;
1204                         gdouble speed = delta_t > 0 ? dist/delta_t : 1000;
1205                         //std::cout << "Mouse speed = " << speed << " px/msec " << std::endl;
1206                         if (speed > 0.02) { // Jitter threshold, might be needed for tablets
1207                                 // We're moving fast, so postpone any snapping until the next GDK_MOTION_NOTIFY event. We
1208                                 // will keep on postponing the snapping as long as the speed is high.
1209                                 // We must snap at some point in time though, so set a watchdog timer at some time from
1210                                 // now, just in case there's no future motion event that drops under the speed limit (when
1211                                 // stopping abruptly)
1212                                 delete ec->_delayed_snap_event;
1213                                 ec->_delayed_snap_event = new DelayedSnapEvent(ec, item, knot, event, origin); // watchdog is reset, i.e. pushed forward in time
1214                                 // If the watchdog expires before a new motion event is received, we will snap (as explained
1215                                 // above). This means however that when the timer is too short, we will always snap and that the
1216                                 // speed threshold is ineffective. In the extreme case the delay is set to zero, and snapping will
1217                                 // be immediate, as it used to be in the old days ;-).
1218                         } else { // Speed is very low, so we're virtually at stand still
1219                                 // But if we're really standing still, then we should snap now. We could use some low-pass filtering,
1220                                 // otherwise snapping occurs for each jitter movement. For this filtering we'll leave the watchdog to expire,
1221                                 // snap, and set a new watchdog again.
1222                                 if (ec->_delayed_snap_event == NULL) { // no watchdog has been set
1223                                         // it might have already expired, so we'll set a new one; the snapping frequency will be limited by this
1224                                         ec->_delayed_snap_event = new DelayedSnapEvent(ec, item, knot, event, origin);
1225                                 } // else: watchdog has been set before and we'll wait for it to expire
1226                         }
1227                 } else {
1228                         // This is the first GDK_MOTION_NOTIFY event, so postpone snapping and set the watchdog
1229                         g_assert(ec->_delayed_snap_event == NULL);
1230                         ec->_delayed_snap_event = new DelayedSnapEvent(ec, item, knot, event, origin);
1231                 }
1232
1233                 prev_pos = event_pos;
1234                 prev_time = event_t;
1235         }
1236 }
1237
1238 gboolean sp_event_context_snap_watchdog_callback(gpointer data)
1239 {
1240         // Snap NOW! For this the "postponed" flag will be reset and the last motion event will be repeated
1241         DelayedSnapEvent *dse = reinterpret_cast<DelayedSnapEvent*>(data);
1242
1243         if (dse == NULL) {
1244                 // This might occur when this method is called directly, i.e. not through the timer
1245                 // E.g. on GDK_BUTTON_RELEASE in sp_event_context_root_handler()
1246                 return FALSE;
1247         }
1248
1249         SPEventContext *ec = dse->getEventContext();
1250         if (ec == NULL || ec->desktop == NULL) {
1251                 return false;
1252         }
1253
1254         SPDesktop *dt = ec->desktop;
1255         dt->namedview->snap_manager.snapprefs.setSnapPostponedGlobally(false);
1256
1257         switch (dse->getOrigin()) {
1258                 case DelayedSnapEvent::EVENTCONTEXT_ROOT_HANDLER:
1259                         sp_event_context_virtual_root_handler(ec, dse->getEvent());
1260                         break;
1261                 case DelayedSnapEvent::EVENTCONTEXT_ITEM_HANDLER:
1262                         {
1263                                 SPItem* item = NULL;
1264                                 item = dse->getItem();
1265                                 if (item && SP_IS_ITEM(item)) {
1266                                         sp_event_context_virtual_item_handler(ec, item, dse->getEvent());
1267                                 }
1268                         }
1269                         break;
1270                 case DelayedSnapEvent::KNOT_HANDLER:
1271                         {
1272                                 SPKnot* knot = dse->getKnot();
1273                                 if (knot && SP_IS_KNOT(knot)) {
1274                                         sp_knot_handler_request_position(dse->getEvent(), knot);
1275                                 }
1276                         }
1277                         break;
1278                 default:
1279                         g_warning("Origin of snap-delay event has not been defined!;");
1280                         break;
1281         }
1282
1283         ec->_delayed_snap_event = NULL;
1284         delete dse;
1285
1286         return FALSE; //Kills the timer and stops it from executing this callback over and over again.
1287 }
1288
1289 void sp_event_context_snap_window_open(SPEventContext *ec, bool show_debug_warnings)
1290 {
1291         // Only when ec->_snap_window_open has been set, Inkscape will know that snapping is active
1292         // and will delay any snapping events (but only when asked to through the preferences)
1293
1294         // When snapping is being delayed, then that will also mean that at some point the last event
1295         // might be re-triggered. This should only occur when Inkscape is still in the same tool or context,
1296         // and even more specifically, the tool should even be in the same state. If for example snapping is being delayed while
1297         // creating a rectangle, then the rect-context will be active and it will be in the "dragging" state
1298         // (see the static boolean variable "dragging" in the sp_rect_context_root_handler). The procedure is
1299         // as follows: call sp_event_context_snap_window_open(*, TRUE) when entering the "dragging" state, which will delay
1300         // snapping from that moment on, and call sp_event_context_snap_window_open(*, FALSE) when leaving the "dragging"
1301         // state. This last call will also make sure that any pending snap events will be canceled.
1302
1303         //std::cout << "sp_event_context_snap_window_open" << std::endl;
1304         if (!ec) {
1305                 if (show_debug_warnings) {
1306                         g_warning("sp_event_context_snap_window_open() has been called without providing an event context!");
1307                 }
1308                 return;
1309         }
1310
1311         if (ec->_snap_window_open == true && show_debug_warnings) {
1312                 g_warning("Snap window was already open! This is a bug, please report it.");
1313         }
1314
1315         ec->_snap_window_open = true;
1316 }
1317
1318 void sp_event_context_snap_window_closed(SPEventContext *ec, bool show_debug_warnings)
1319 {
1320         //std::cout << "sp_event_context_snap_window_closed" << std::endl;
1321         if (!ec) {
1322                 if (show_debug_warnings) {
1323                         g_warning("sp_event_context_snap_window_closed() has been called without providing an event context!");
1324                 }
1325                 return;
1326         }
1327
1328         if (ec->_snap_window_open == false && show_debug_warnings) {
1329                 g_warning("Snap window was already closed! This is a bug, please report it.");
1330         }
1331
1332         ec->_snap_window_open = false;
1333
1334         delete ec->_delayed_snap_event;
1335         ec->_delayed_snap_event = NULL;
1336 }
1337
1338
1339
1340 /*
1341   Local Variables:
1342   mode:c++
1343   c-file-style:"stroustrup"
1344   c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
1345   indent-tabs-mode:nil
1346   fill-column:99
1347   End:
1348 */
1349 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :