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     double const zoom_inc = prefs->getDoubleLimited(
 352             "/options/zoomincrement/value", M_SQRT2, 1.01, 10);
 353     double const acceleration = prefs->getDoubleLimited(
 354             "/options/scrollingacceleration/value", 0, 0, 6);
 355     int const key_scroll = prefs->getIntLimited(
 356             "/options/keyscroll/value", 10, 0, 1000);
 357     int const wheel_scroll = prefs->getIntLimited(
 358             "/options/wheelscroll/value", 40, 0, 1000);
 359
 360     gint ret = FALSE;
 361
 362     switch (event->type) {
 363         case GDK_2BUTTON_PRESS:
 364             if (panning) {
 365                 panning = 0;
 366                 sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate),
 367                         event->button.time);
 368                 ret = TRUE;
 369             } else {
 370                 /* sp_desktop_dialog(); */
 371             }
 372             break;
 373         case GDK_BUTTON_PRESS:
 374
 375             // save drag origin
 376             xp = (gint) event->button.x;
 377             yp = (gint) event->button.y;
 378             within_tolerance = true;
 379
 380             button_w = Geom::Point(event->button.x, event->button.y);
 381
 382             switch (event->button.button) {
 383                 case 1:
 384                     if (event_context->space_panning) {
 385                         panning = 1;
 386                         sp_canvas_item_grab(SP_CANVAS_ITEM(desktop->acetate),
 387                             GDK_KEY_RELEASE_MASK | GDK_BUTTON_RELEASE_MASK | GDK_POINTER_MOTION_MASK | GDK_POINTER_MOTION_HINT_MASK,
 388                             NULL, event->button.time-1);
 389                         ret = TRUE;
 390                     }
 391                     break;
 392                 case 2:
 393                     if (event->button.state == GDK_SHIFT_MASK) {
 394                         zoom_rb = 2;
 395                     } else {
 396                         panning = 2;
 397                         sp_canvas_item_grab(SP_CANVAS_ITEM(desktop->acetate),
 398                             GDK_BUTTON_RELEASE_MASK | GDK_POINTER_MOTION_MASK | GDK_POINTER_MOTION_HINT_MASK,
 399                             NULL, event->button.time-1);
 400                     }
 401                     ret = TRUE;
 402                     break;
 403                 case 3:
 404                     if (event->button.state & GDK_SHIFT_MASK
 405                             || event->button.state & GDK_CONTROL_MASK) {
 406                         panning = 3;
 407                         sp_canvas_item_grab(SP_CANVAS_ITEM(desktop->acetate),
 408                                 GDK_BUTTON_RELEASE_MASK | GDK_POINTER_MOTION_MASK | GDK_POINTER_MOTION_HINT_MASK,
 409                                 NULL, event->button.time);
 410                         ret = TRUE;
 411                     } else {
 412                         sp_event_root_menu_popup(desktop, NULL, event);
 413                     }
 414                     break;
 415                 default:
 416                     break;
 417             }
 418             break;
 419         case GDK_MOTION_NOTIFY:
 420             if (panning) {
 421                 if ((panning == 2 && !(event->motion.state & GDK_BUTTON2_MASK))
 422                         || (panning == 1 && !(event->motion.state & GDK_BUTTON1_MASK))
 423                         || (panning == 3 && !(event->motion.state & GDK_BUTTON3_MASK))
 424                    ) {
 425                     /* Gdk seems to lose button release for us sometimes :-( */
 426                     panning = 0;
 427                     sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate),
 428                             event->button.time);
 429                     ret = TRUE;
 430                 } else {
 431                     if ( within_tolerance
 432                          && ( abs( (gint) event->motion.x - xp ) < tolerance )
 433                          && ( abs( (gint) event->motion.y - yp ) < tolerance ))
 434                     {
 435                         // do not drag if we're within tolerance from origin
 436                         break;
 437                     }
 438                     // Once the user has moved farther than tolerance from
 439                     // the original location (indicating they intend to move
 440                     // the object, not click), then always process the motion
 441                     // notify coordinates as given (no snapping back to origin)
 442                     within_tolerance = false;
 443
 444                     // gobble subsequent motion events to prevent "sticking"
 445                     // when scrolling is slow
 446                     gobble_motion_events(panning == 2 ?
 447                                          GDK_BUTTON2_MASK :
 448                                          (panning == 1 ? GDK_BUTTON1_MASK : GDK_BUTTON3_MASK));
 449
 450                     Geom::Point const motion_w(event->motion.x, event->motion.y);
 451                     Geom::Point const moved_w( motion_w - button_w );
 452                     event_context->desktop->scroll_world(moved_w, true); // we're still scrolling, do not redraw
 453                     ret = TRUE;
 454                 }
 455             } else if (zoom_rb) {
 456                 Geom::Point const motion_w(event->motion.x, event->motion.y);
 457                 Geom::Point const motion_dt(desktop->w2d(motion_w));
 458
 459                 if ( within_tolerance
 460                      && ( abs( (gint) event->motion.x - xp ) < tolerance )
 461                      && ( abs( (gint) event->motion.y - yp ) < tolerance ) ) {
 462                     break; // do not drag if we're within tolerance from origin
 463                 }
 464                 // Once the user has moved farther than tolerance from the original location
 465                 // (indicating they intend to move the object, not click), then always process the
 466                 // motion notify coordinates as given (no snapping back to origin)
 467                 within_tolerance = false;
 468
 469                 if (Inkscape::Rubberband::get(desktop)->is_started()) {
 470                     Inkscape::Rubberband::get(desktop)->move(motion_dt);
 471                 } else {
 472                     Inkscape::Rubberband::get(desktop)->start(desktop, motion_dt);
 473                 }
 474                 if (zoom_rb == 2)
 475                     gobble_motion_events(GDK_BUTTON2_MASK);
 476             }
 477             break;
 478         case GDK_BUTTON_RELEASE:
 479             xp = yp = 0;
 480             if (within_tolerance && (panning || zoom_rb)) {
 481                 zoom_rb = 0;
 482                 if (panning) {
 483                     panning = 0;
 484                     sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate),
 485                                       event->button.time);
 486                 }
 487                 Geom::Point const event_w(event->button.x, event->button.y);
 488                 Geom::Point const event_dt(desktop->w2d(event_w));
 489                 desktop->zoom_relative_keep_point(event_dt,
 490                           (event->button.state & GDK_SHIFT_MASK) ? 1/zoom_inc : zoom_inc);
 491                 desktop->updateNow();
 492                 ret = TRUE;
 493             } else if (panning == event->button.button) {
 494                 panning = 0;
 495                 sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate),
 496                                       event->button.time);
 497
 498                 // in slow complex drawings, some of the motion events are lost;
 499                 // to make up for this, we scroll it once again to the button-up event coordinates
 500                 // (i.e. canvas will always get scrolled all the way to the mouse release point,
 501                 // even if few intermediate steps were visible)
 502                 Geom::Point const motion_w(event->button.x, event->button.y);
 503                 Geom::Point const moved_w( motion_w - button_w );
 504                 event_context->desktop->scroll_world(moved_w);
 505                 desktop->updateNow();
 506                 ret = TRUE;
 507             } else if (zoom_rb == event->button.button) {
 508                 zoom_rb = 0;
 509                 Geom::OptRect const b = Inkscape::Rubberband::get(desktop)->getRectangle();
 510                 Inkscape::Rubberband::get(desktop)->stop();
 511                 if (b && !within_tolerance) {
 512                     desktop->set_display_area(*b, 10);
 513                 }
 514                 ret = TRUE;
 515             }
 516             break;
 517         case GDK_KEY_PRESS:
 518             switch (get_group0_keyval(&event->key)) {
 519                 // GDK insists on stealing these keys (F1 for no idea what, tab for cycling widgets
 520                 // in the editing window). So we resteal them back and run our regular shortcut
 521                 // invoker on them.
 522                 unsigned int shortcut;
 523                 case GDK_Tab:
 524                 case GDK_ISO_Left_Tab:
 525                 case GDK_F1:
 526                     shortcut = get_group0_keyval(&event->key);
 527                     if (event->key.state & GDK_SHIFT_MASK)
 528                         shortcut |= SP_SHORTCUT_SHIFT_MASK;
 529                     if (event->key.state & GDK_CONTROL_MASK)
 530                         shortcut |= SP_SHORTCUT_CONTROL_MASK;
 531                     if (event->key.state & GDK_MOD1_MASK)
 532                         shortcut |= SP_SHORTCUT_ALT_MASK;
 533                     ret = sp_shortcut_invoke(shortcut, desktop);
 534                     break;
 535
 536                 case GDK_D:
 537                 case GDK_d:
 538                     if (!MOD__SHIFT && !MOD__CTRL && !MOD__ALT) {
 539                         sp_toggle_dropper(desktop);
 540                         ret = TRUE;
 541                     }
 542                     break;
 543                 case GDK_Q:
 544                 case GDK_q:
 545                                         if (desktop->quick_zoomed()) {
 546                                                 ret = TRUE;
 547                                         }
 548                     if (!MOD__SHIFT && !MOD__CTRL && !MOD__ALT) {
 549                                                 desktop->zoom_quick(true);
 550                         ret = TRUE;
 551                     }
 552                     break;
 553                 case GDK_W:
 554                 case GDK_w:
 555                 case GDK_F4:
 556                     /* Close view */
 557                     if (MOD__CTRL_ONLY) {
 558                         sp_ui_close_view(NULL);
 559                         ret = TRUE;
 560                     }
 561                     break;
 562                 case GDK_Left: // Ctrl Left
 563                 case GDK_KP_Left:
 564                 case GDK_KP_4:
 565                     if (MOD__CTRL_ONLY) {
 566                         int i = (int) floor(key_scroll * accelerate_scroll(event, acceleration, sp_desktop_canvas(desktop)));
 567                         gobble_key_events(get_group0_keyval(&event->key),
 568                                 GDK_CONTROL_MASK);
 569                         event_context->desktop->scroll_world(i, 0);
 570                         ret = TRUE;
 571                     }
 572                     break;
 573                 case GDK_Up: // Ctrl Up
 574                 case GDK_KP_Up:
 575                 case GDK_KP_8:
 576                     if (MOD__CTRL_ONLY) {
 577                         int i = (int) floor(key_scroll * accelerate_scroll(event, acceleration, sp_desktop_canvas(desktop)));
 578                         gobble_key_events(get_group0_keyval(&event->key),
 579                                 GDK_CONTROL_MASK);
 580                         event_context->desktop->scroll_world(0, i);
 581                         ret = TRUE;
 582                     }
 583                     break;
 584                 case GDK_Right: // Ctrl Right
 585                 case GDK_KP_Right:
 586                 case GDK_KP_6:
 587                     if (MOD__CTRL_ONLY) {
 588                         int i = (int) floor(key_scroll * accelerate_scroll(event, acceleration, sp_desktop_canvas(desktop)));
 589                         gobble_key_events(get_group0_keyval(&event->key),
 590                                 GDK_CONTROL_MASK);
 591                         event_context->desktop->scroll_world(-i, 0);
 592                         ret = TRUE;
 593                     }
 594                     break;
 595                 case GDK_Down: // Ctrl Down
 596                 case GDK_KP_Down:
 597                 case GDK_KP_2:
 598                     if (MOD__CTRL_ONLY) {
 599                         int i = (int) floor(key_scroll * accelerate_scroll(event, acceleration, sp_desktop_canvas(desktop)));
 600                         gobble_key_events(get_group0_keyval(&event->key),
 601                                 GDK_CONTROL_MASK);
 602                         event_context->desktop->scroll_world(0, -i);
 603                         ret = TRUE;
 604                     }
 605                     break;
 606                 case GDK_F10:
 607                     if (MOD__SHIFT_ONLY) {
 608                         sp_event_root_menu_popup(desktop, NULL, event);
 609                         ret= TRUE;
 610                     }
 611                     break;
 612                 case GDK_space:
 613                     if (prefs->getBool("/options/spacepans/value")) {
 614                         event_context->space_panning = true;
 615                         event_context->_message_context->set(Inkscape::INFORMATION_MESSAGE, _("<b>Space+mouse drag</b> to pan canvas"));
 616                         ret= TRUE;
 617                     } else {
 618                         sp_toggle_selector(desktop);
 619                         ret= TRUE;
 620                     }
 621                     break;
 622                 case GDK_z:
 623                 case GDK_Z:
 624                     if (MOD__ALT_ONLY) {
 625                         desktop->zoom_grab_focus();
 626                         ret = TRUE;
 627                     }
 628                     break;
 629                 default:
 630                     break;
 631             }
 632             break;
 633         case GDK_KEY_RELEASE:
 634             switch (get_group0_keyval(&event->key)) {
 635                 case GDK_space:
 636                     if (event_context->space_panning) {
 637                         event_context->space_panning = false;
 638                         event_context->_message_context->clear();
 639                         if (panning == 1) {
 640                             panning = 0;
 641                             sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate),
 642                                   event->key.time);
 643                             desktop->updateNow();
 644                         }
 645                         ret= TRUE;
 646                     }
 647                     break;
 648                 case GDK_Q:
 649                 case GDK_q:
 650                                         if (desktop->quick_zoomed()) {
 651                                                 desktop->zoom_quick(false);
 652                         ret = TRUE;
 653                     }
 654                     break;
 655                 default:
 656                     break;
 657             }
 658             break;
 659         case GDK_SCROLL:
 660         {
 661             bool ctrl = (event->scroll.state & GDK_CONTROL_MASK);
 662             bool wheelzooms = prefs->getBool("/options/wheelzooms/value");
 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                 switch (event->scroll.direction) {
 680                     case GDK_SCROLL_UP:
 681                         rel_zoom = zoom_inc;
 682                         break;
 683                     case GDK_SCROLL_DOWN:
 684                         rel_zoom = 1 / zoom_inc;
 685                         break;
 686                     default:
 687                         rel_zoom = 0.0;
 688                         break;
 689                 }
 690                 if (rel_zoom != 0.0) {
 691                     Geom::Point const scroll_dt = desktop->point();
 692                     desktop->zoom_relative_keep_point(scroll_dt, rel_zoom);
 693                 }
 694
 695                 /* no modifier, pan up--down (left--right on multiwheel mice?) */
 696             } else {
 697                 switch (event->scroll.direction) {
 698                     case GDK_SCROLL_UP:
 699                         desktop->scroll_world(0, wheel_scroll);
 700                         break;
 701                     case GDK_SCROLL_DOWN:
 702                         desktop->scroll_world(0, -wheel_scroll);
 703                         break;
 704                     case GDK_SCROLL_LEFT:
 705                         desktop->scroll_world(wheel_scroll, 0);
 706                         break;
 707                     case GDK_SCROLL_RIGHT:
 708                         desktop->scroll_world(-wheel_scroll, 0);
 709                         break;
 710                 }
 711             }
 712             break;
 713         }
 714         default:
 715             break;
 716     }
 717
 718     return ret;
 719 }
 720
 721 /**
 722  * Handles item specific events. Gets called from Gdk.
 723  *
 724  * Only reacts to right mouse button at the moment.
 725  * \todo Fixme: do context sensitive popup menu on items.
 726  */
 727 gint
 728 sp_event_context_private_item_handler(SPEventContext *ec, SPItem *item, GdkEvent *event)
 729 {
 730     int ret = FALSE;
 731
 732     switch (event->type) {
 733         case GDK_BUTTON_PRESS:
 734             if ((event->button.button == 3)
 735                     && !(event->button.state & GDK_SHIFT_MASK || event->button.state & GDK_CONTROL_MASK)) {
 736                 sp_event_root_menu_popup(ec->desktop, item, event);
 737                 ret = TRUE;
 738             }
 739             break;
 740         default:
 741             break;
 742     }
 743
 744     return ret;
 745 }
 746
 747 /**
 748  * @brief An observer that relays pref changes to the derived classes
 749  */
 750 class ToolPrefObserver : public Inkscape::Preferences::Observer {
 751 public:
 752     ToolPrefObserver(Glib::ustring const &path, SPEventContext *ec) :
 753         Inkscape::Preferences::Observer(path),
 754         _ec(ec) {}
 755     virtual void notify(Inkscape::Preferences::Entry const &val)
 756     {
 757         if (((SPEventContextClass *) G_OBJECT_GET_CLASS(_ec))->set) {
 758             ((SPEventContextClass *) G_OBJECT_GET_CLASS(_ec))->set(_ec,
 759                 const_cast<Inkscape::Preferences::Entry*>(&val));
 760         }
 761     }
 762 private:
 763     SPEventContext * const _ec;
 764 };
 765
 766 /**
 767  * Creates new SPEventContext object and calls its virtual setup() function.
 768  * @todo This is bogus. pref_path should be a private property of the inheriting objects.
 769  */
 770 SPEventContext *
 771 sp_event_context_new(GType type, SPDesktop *desktop, gchar const *pref_path, unsigned int key)
 772 {
 773     g_return_val_if_fail(g_type_is_a(type, SP_TYPE_EVENT_CONTEXT), NULL);
 774     g_return_val_if_fail(desktop != NULL, NULL);
 775
 776     SPEventContext *const ec = (SPEventContext*)g_object_new(type, NULL);
 777
 778     ec->desktop = desktop;
 779     ec->_message_context = new Inkscape::MessageContext(desktop->messageStack());
 780     ec->key = key;
 781     ec->pref_observer = NULL;
 782
 783     if (pref_path) {
 784         ec->pref_observer = new ToolPrefObserver(pref_path, ec);
 785
 786         Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 787         prefs->addObserver(*(ec->pref_observer));
 788     }
 789
 790     if (((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->setup)
 791         ((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->setup(ec);
 792
 793     return ec;
 794 }
 795
 796 /**
 797  * Finishes SPEventContext.
 798  */
 799 void
 800 sp_event_context_finish(SPEventContext *ec)
 801 {
 802     g_return_if_fail(ec != NULL);
 803     g_return_if_fail(SP_IS_EVENT_CONTEXT(ec));
 804
 805     ec->enableSelectionCue(false);
 806
 807     if (ec->next) {
 808         g_warning("Finishing event context with active link\n");
 809     }
 810
 811     if (((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->finish)
 812         ((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->finish(ec);
 813 }
 814
 815 //-------------------------------member functions
 816
 817 /**
 818  * Enables/disables the SPEventContext's SelCue.
 819  */
 820 void SPEventContext::enableSelectionCue(bool enable) {
 821     if (enable) {
 822         if (!_selcue) {
 823             _selcue = new Inkscape::SelCue(desktop);
 824         }
 825     } else {
 826         delete _selcue;
 827         _selcue = NULL;
 828     }
 829 }
 830
 831 /**
 832  * Enables/disables the SPEventContext's GrDrag.
 833  */
 834 void SPEventContext::enableGrDrag(bool enable) {
 835     if (enable) {
 836         if (!_grdrag) {
 837             _grdrag = new GrDrag(desktop);
 838         }
 839     } else {
 840         if (_grdrag) {
 841             delete _grdrag;
 842             _grdrag = NULL;
 843         }
 844     }
 845 }
 846
 847 /**
 848  * Calls virtual set() function of SPEventContext.
 849  */
 850 void
 851 sp_event_context_read(SPEventContext *ec, gchar const *key)
 852 {
 853     g_return_if_fail(ec != NULL);
 854     g_return_if_fail(SP_IS_EVENT_CONTEXT(ec));
 855     g_return_if_fail(key != NULL);
 856
 857     if (((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->set) {
 858         Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 859         Inkscape::Preferences::Entry val = prefs->getEntry(
 860             ec->pref_observer->observed_path + '/' + key );
 861         ((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->set(ec, &val);
 862     }
 863 }
 864
 865 /**
 866  * Calls virtual activate() function of SPEventContext.
 867  */
 868 void
 869 sp_event_context_activate(SPEventContext *ec)
 870 {
 871     g_return_if_fail(ec != NULL);
 872     g_return_if_fail(SP_IS_EVENT_CONTEXT(ec));
 873
 874     // Make sure no delayed snapping events are carried over after switching contexts
 875     // (this is only an additional safety measure against sloppy coding, because each
 876     // context should take care of this by itself. It might be hard to get each and every
 877     // context perfect though)
 878     sp_event_context_snap_window_closed(ec, false);
 879
 880     if (((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->activate)
 881         ((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->activate(ec);
 882 }
 883
 884 /**
 885  * Calls virtual deactivate() function of SPEventContext.
 886  */
 887 void
 888 sp_event_context_deactivate(SPEventContext *ec)
 889 {
 890     g_return_if_fail(ec != NULL);
 891     g_return_if_fail(SP_IS_EVENT_CONTEXT(ec));
 892
 893     if (((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->deactivate)
 894         ((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->deactivate(ec);
 895 }
 896
 897 /**
 898  * Calls virtual root_handler(), the main event handling function.
 899  */
 900 gint
 901 sp_event_context_root_handler(SPEventContext * event_context, GdkEvent * event)
 902 {
 903     //std::cout << "sp_event_context_root_handler" << std::endl;
 904         switch (event->type) {
 905                 case GDK_MOTION_NOTIFY:
 906                         sp_event_context_snap_delay_handler(event_context, NULL, NULL, (GdkEventMotion *)event, DelayedSnapEvent::EVENTCONTEXT_ROOT_HANDLER);
 907                         break;
 908                 case GDK_BUTTON_RELEASE:
 909                         if (event_context->_delayed_snap_event) {
 910                                 // If we have any pending snapping action, then invoke it now
 911                                 sp_event_context_snap_watchdog_callback(event_context->_delayed_snap_event);
 912                         }
 913                         break;
 914                 case GDK_BUTTON_PRESS:
 915         case GDK_2BUTTON_PRESS:
 916         case GDK_3BUTTON_PRESS:
 917                         // Snapping will be on hold if we're moving the mouse at high speeds. When starting
 918                         // drawing a new shape we really should snap though.
 919                         event_context->desktop->namedview->snap_manager.snapprefs.setSnapPostponedGlobally(false);
 920                         break;
 921         default:
 922                 break;
 923     }
 924
 925     return sp_event_context_virtual_root_handler(event_context, event);
 926 }
 927
 928 gint
 929 sp_event_context_virtual_root_handler(SPEventContext * event_context, GdkEvent * event)
 930 {
 931         //std::cout << "sp_event_context_virtual_root_handler -> postponed: " << event_context->desktop->namedview->snap_manager.snapprefs.getSnapPostponedGlobally() << std::endl;
 932
 933         gint ret = ((SPEventContextClass *) G_OBJECT_GET_CLASS(event_context))->root_handler(event_context, event);
 934         set_event_location(event_context->desktop, event);
 935         return ret;
 936 }
 937
 938 /**
 939  * Calls virtual item_handler(), the item event handling function.
 940  */
 941 gint
 942 sp_event_context_item_handler(SPEventContext * event_context, SPItem * item, GdkEvent * event)
 943 {
 944         //std::cout << "sp_event_context_item_handler" << std::endl;
 945         switch (event->type) {
 946                 case GDK_MOTION_NOTIFY:
 947                         sp_event_context_snap_delay_handler(event_context, item, NULL, (GdkEventMotion *)event, DelayedSnapEvent::EVENTCONTEXT_ITEM_HANDLER);
 948                         break;
 949                 case GDK_BUTTON_RELEASE:
 950                         if (event_context->_delayed_snap_event) {
 951                                 // If we have any pending snapping action, then invoke it now
 952                                 sp_event_context_snap_watchdog_callback(event_context->_delayed_snap_event);
 953                         }
 954                         break;
 955                 /*case GDK_BUTTON_PRESS:
 956                 case GDK_2BUTTON_PRESS:
 957                 case GDK_3BUTTON_PRESS:
 958                         // Snapping will be on hold if we're moving the mouse at high speeds. When starting
 959                         // drawing a new shape we really should snap though.
 960                         event_context->desktop->namedview->snap_manager.snapprefs.setSnapPostponedGlobally(false);
 961                         break;
 962                 */
 963                 default:
 964                         break;
 965         }
 966
 967     return sp_event_context_virtual_item_handler(event_context, item, event);
 968 }
 969
 970 gint
 971 sp_event_context_virtual_item_handler(SPEventContext * event_context, SPItem * item, GdkEvent * event)
 972 {
 973         gint ret = ((SPEventContextClass *) G_OBJECT_GET_CLASS(event_context))->item_handler(event_context, item, event);
 974
 975         if (! ret) {
 976                 ret = sp_event_context_virtual_root_handler(event_context, event);
 977         } else {
 978                 set_event_location(event_context->desktop, event);
 979         }
 980
 981         return ret;
 982 }
 983
 984 /**
 985  * Emits 'position_set' signal on desktop and shows coordinates on status bar.
 986  */
 987 static void set_event_location(SPDesktop *desktop, GdkEvent *event)
 988 {
 989     if (event->type != GDK_MOTION_NOTIFY) {
 990         return;
 991     }
 992
 993     Geom::Point const button_w(event->button.x, event->button.y);
 994     Geom::Point const button_dt(desktop->w2d(button_w));
 995     desktop->setPosition(button_dt);
 996     desktop->set_coordinate_status(button_dt);
 997 }
 998
 999 //-------------------------------------------------------------------
1000 /**
1001  * Create popup menu and tell Gtk to show it.
1002  */
1003 void
1004 sp_event_root_menu_popup(SPDesktop *desktop, SPItem *item, GdkEvent *event)
1005 {
1006     GtkWidget *menu;
1007
1008     /* fixme: This is not what I want but works for now (Lauris) */
1009     if (event->type == GDK_KEY_PRESS) {
1010         item = sp_desktop_selection(desktop)->singleItem();
1011     }
1012     menu = sp_ui_context_menu(desktop, item);
1013     gtk_widget_show(menu);
1014
1015     switch (event->type) {
1016         case GDK_BUTTON_PRESS:
1017             gtk_menu_popup(GTK_MENU(menu), NULL, NULL, 0, NULL, event->button.button, event->button.time);
1018             break;
1019         case GDK_KEY_PRESS:
1020             gtk_menu_popup(GTK_MENU(menu), NULL, NULL, 0, NULL, 0, event->key.time);
1021             break;
1022         default:
1023             break;
1024     }
1025 }
1026
1027 /**
1028  * Show tool context specific modifier tip.
1029  */
1030 void
1031 sp_event_show_modifier_tip(Inkscape::MessageContext *message_context,
1032         GdkEvent *event, gchar const *ctrl_tip, gchar const *shift_tip,
1033         gchar const *alt_tip)
1034 {
1035     guint keyval = get_group0_keyval(&event->key);
1036
1037     bool ctrl = ctrl_tip && (MOD__CTRL
1038             || (keyval == GDK_Control_L)
1039             || (keyval == GDK_Control_R));
1040     bool shift = shift_tip
1041         && (MOD__SHIFT || (keyval == GDK_Shift_L) || (keyval == GDK_Shift_R));
1042     bool alt = alt_tip
1043         && (MOD__ALT
1044                 || (keyval == GDK_Alt_L)
1045                 || (keyval == GDK_Alt_R)
1046                 || (keyval == GDK_Meta_L)
1047                 || (keyval == GDK_Meta_R));
1048
1049     gchar *tip = g_strdup_printf("%s%s%s%s%s",
1050                                  ( ctrl ? ctrl_tip : "" ),
1051                                  ( ctrl && (shift || alt) ? "; " : "" ),
1052                                  ( shift ? shift_tip : "" ),
1053                                  ( (ctrl || shift) && alt ? "; " : "" ),
1054                                  ( alt ? alt_tip : "" ));
1055
1056     if (strlen(tip) > 0) {
1057         message_context->flash(Inkscape::INFORMATION_MESSAGE, tip);
1058     }
1059
1060     g_free(tip);
1061 }
1062
1063 /**
1064  * Return the keyval corresponding to the key event in group 0, i.e.,
1065  * in the main (English) layout.
1066  *
1067  * Use this instead of simply event->keyval, so that your keyboard shortcuts
1068  * work regardless of layouts (e.g., in Cyrillic).
1069  */
1070 guint
1071 get_group0_keyval(GdkEventKey *event)
1072 {
1073     guint keyval = 0;
1074     gdk_keymap_translate_keyboard_state(
1075             gdk_keymap_get_for_display(gdk_display_get_default()),
1076             event->hardware_keycode,
1077             (GdkModifierType) event->state,
1078             0   /*event->key.group*/,
1079             &keyval, NULL, NULL, NULL);
1080     return keyval;
1081 }
1082
1083 /**
1084  * Returns item at point p in desktop.
1085  *
1086  * If state includes alt key mask, cyclically selects under; honors
1087  * into_groups.
1088  */
1089 SPItem *
1090 sp_event_context_find_item (SPDesktop *desktop, Geom::Point const &p,
1091         bool select_under, bool into_groups)
1092 {
1093     SPItem *item;
1094
1095     if (select_under) {
1096         SPItem *selected_at_point =
1097             desktop->item_from_list_at_point_bottom (desktop->selection->itemList(), p);
1098         item = desktop->item_at_point(p, into_groups, selected_at_point);
1099         if (item == NULL) { // we may have reached bottom, flip over to the top
1100             item = desktop->item_at_point(p, into_groups, NULL);
1101         }
1102     } else
1103         item = desktop->item_at_point(p, into_groups, NULL);
1104
1105     return item;
1106 }
1107
1108 /**
1109  * Returns item if it is under point p in desktop, at any depth; otherwise returns NULL.
1110  *
1111  * Honors into_groups.
1112  */
1113 SPItem *
1114 sp_event_context_over_item (SPDesktop *desktop, SPItem *item, Geom::Point const &p)
1115 {
1116     GSList *temp = NULL;
1117     temp = g_slist_prepend (temp, item);
1118     SPItem *item_at_point = desktop->item_from_list_at_point_bottom (temp, p);
1119     g_slist_free (temp);
1120
1121     return item_at_point;
1122 }
1123
1124 ShapeEditor *
1125 sp_event_context_get_shape_editor (SPEventContext *ec)
1126 {
1127     return ec->shape_editor;
1128 }
1129
1130 void
1131 event_context_print_event_info(GdkEvent *event, bool print_return) {
1132     switch (event->type) {
1133         case GDK_BUTTON_PRESS:
1134             g_print ("GDK_BUTTON_PRESS");
1135             break;
1136         case GDK_2BUTTON_PRESS:
1137             g_print ("GDK_2BUTTON_PRESS");
1138             break;
1139         case GDK_3BUTTON_PRESS:
1140             g_print ("GDK_3BUTTON_PRESS");
1141             break;
1142
1143         case GDK_MOTION_NOTIFY:
1144             g_print ("GDK_MOTION_NOTIFY");
1145             break;
1146         case GDK_ENTER_NOTIFY:
1147             g_print ("GDK_ENTER_NOTIFY");
1148             break;
1149
1150         case GDK_LEAVE_NOTIFY:
1151             g_print ("GDK_LEAVE_NOTIFY");
1152             break;
1153         case GDK_BUTTON_RELEASE:
1154             g_print ("GDK_BUTTON_RELEASE");
1155             break;
1156
1157         case GDK_KEY_PRESS:
1158             g_print ("GDK_KEY_PRESS: %d", get_group0_keyval(&event->key));
1159             break;
1160         case GDK_KEY_RELEASE:
1161             g_print ("GDK_KEY_RELEASE: %d", get_group0_keyval(&event->key));
1162             break;
1163         default:
1164             //g_print ("even type not recognized");
1165             break;
1166     }
1167
1168     if (print_return) {
1169         g_print ("\n");
1170     }
1171 }
1172
1173 void sp_event_context_snap_delay_handler(SPEventContext *ec, SPItem* const item, SPKnot* const knot, GdkEventMotion *event, DelayedSnapEvent::DelayedSnapEventOrigin origin)
1174 {
1175         static guint32 prev_time;
1176         static boost::optional<Geom::Point> prev_pos;
1177
1178         // Snapping occurs when dragging with the left mouse button down, or when hovering e.g. in the pen tool with left mouse button up
1179     bool const c1 = event->state & GDK_BUTTON2_MASK; // We shouldn't hold back any events when other mouse buttons have been
1180     bool const c2 = event->state & GDK_BUTTON3_MASK; // pressed, e.g. when scrolling with the middle mouse button; if we do then
1181                                                                                                      // Inkscape will get stuck in an unresponsive state
1182
1183     if (ec->_snap_window_open && !c1 && !c2 && ec->desktop && ec->desktop->namedview->snap_manager.snapprefs.getSnapEnabledGlobally()) {
1184         // Snap when speed drops below e.g. 0.02 px/msec, or when no motion events have occurred for some period.
1185                 // i.e. snap when we're at stand still. A speed threshold enforces snapping for tablets, which might never
1186                 // be fully at stand still and might keep spitting out motion events.
1187         ec->desktop->namedview->snap_manager.snapprefs.setSnapPostponedGlobally(true); // put snapping on hold
1188
1189         Geom::Point event_pos(event->x, event->y);
1190                 guint32 event_t = gdk_event_get_time ( (GdkEvent *) event );
1191
1192                 if (prev_pos) {
1193                         Geom::Coord dist = Geom::L2(event_pos - *prev_pos);
1194                         guint32 delta_t = event_t - prev_time;
1195                         gdouble speed = delta_t > 0 ? dist/delta_t : 1000;
1196                         //std::cout << "Mouse speed = " << speed << " px/msec " << std::endl;
1197                         if (speed > 0.02) { // Jitter threshold, might be needed for tablets
1198                                 // We're moving fast, so postpone any snapping until the next GDK_MOTION_NOTIFY event. We
1199                                 // will keep on postponing the snapping as long as the speed is high.
1200                                 // We must snap at some point in time though, so set a watchdog timer at some time from
1201                                 // now, just in case there's no future motion event that drops under the speed limit (when
1202                                 // stopping abruptly)
1203                                 delete ec->_delayed_snap_event;
1204                                 ec->_delayed_snap_event = new DelayedSnapEvent(ec, item, knot, event, origin); // watchdog is reset, i.e. pushed forward in time
1205                                 // If the watchdog expires before a new motion event is received, we will snap (as explained
1206                                 // above). This means however that when the timer is too short, we will always snap and that the
1207                                 // speed threshold is ineffective. In the extreme case the delay is set to zero, and snapping will
1208                                 // be immediate, as it used to be in the old days ;-).
1209                         } else { // Speed is very low, so we're virtually at stand still
1210                                 // But if we're really standing still, then we should snap now. We could use some low-pass filtering,
1211                                 // otherwise snapping occurs for each jitter movement. For this filtering we'll leave the watchdog to expire,
1212                                 // snap, and set a new watchdog again.
1213                                 if (ec->_delayed_snap_event == NULL) { // no watchdog has been set
1214                                         // it might have already expired, so we'll set a new one; the snapping frequency will be limited by this
1215                                         ec->_delayed_snap_event = new DelayedSnapEvent(ec, item, knot, event, origin);
1216                                 } // else: watchdog has been set before and we'll wait for it to expire
1217                         }
1218                 } else {
1219                         // This is the first GDK_MOTION_NOTIFY event, so postpone snapping and set the watchdog
1220                         g_assert(ec->_delayed_snap_event == NULL);
1221                         ec->_delayed_snap_event = new DelayedSnapEvent(ec, item, knot, event, origin);
1222                 }
1223
1224                 prev_pos = event_pos;
1225                 prev_time = event_t;
1226         }
1227 }
1228
1229 gboolean sp_event_context_snap_watchdog_callback(gpointer data)
1230 {
1231         // Snap NOW! For this the "postponed" flag will be reset and the last motion event will be repeated
1232         DelayedSnapEvent *dse = reinterpret_cast<DelayedSnapEvent*>(data);
1233
1234         if (dse == NULL) {
1235                 // This might occur when this method is called directly, i.e. not through the timer
1236                 // E.g. on GDK_BUTTON_RELEASE in sp_event_context_root_handler()
1237                 return FALSE;
1238         }
1239
1240         SPEventContext *ec = dse->getEventContext();
1241         if (ec == NULL || ec->desktop == NULL) {
1242                 return false;
1243         }
1244
1245         SPDesktop *dt = ec->desktop;
1246         dt->namedview->snap_manager.snapprefs.setSnapPostponedGlobally(false);
1247
1248         switch (dse->getOrigin()) {
1249                 case DelayedSnapEvent::EVENTCONTEXT_ROOT_HANDLER:
1250                         sp_event_context_virtual_root_handler(ec, dse->getEvent());
1251                         break;
1252                 case DelayedSnapEvent::EVENTCONTEXT_ITEM_HANDLER:
1253                         g_assert(dse->getItem() != NULL);
1254                         sp_event_context_virtual_item_handler(ec, dse->getItem(), dse->getEvent());
1255                         break;
1256                 case DelayedSnapEvent::KNOT_HANDLER:
1257                         g_assert(dse->getKnot() != NULL);
1258                         sp_knot_handler_request_position(dse->getEvent(), dse->getKnot());
1259                         break;
1260                 default:
1261                         g_warning("Origin of snap-delay event has not been defined!;");
1262                         break;
1263         }
1264
1265         ec->_delayed_snap_event = NULL;
1266         delete dse;
1267
1268         return FALSE; //Kills the timer and stops it from executing this callback over and over again.
1269 }
1270
1271 void sp_event_context_snap_window_open(SPEventContext *ec, bool show_debug_warnings)
1272 {
1273         // Only when ec->_snap_window_open has been set, Inkscape will know that snapping is active
1274         // and will delay any snapping events (but only when asked to through the preferences)
1275
1276         // When snapping is being delayed, then that will also mean that at some point the last event
1277         // might be re-triggered. This should only occur when Inkscape is still in the same tool or context,
1278         // and even more specifically, the tool should even be in the same state. If for example snapping is being delayed while
1279         // creating a rectangle, then the rect-context will be active and it will be in the "dragging" state
1280         // (see the static boolean variable "dragging" in the sp_rect_context_root_handler). The procedure is
1281         // as follows: call sp_event_context_snap_window_open(*, TRUE) when entering the "dragging" state, which will delay
1282         // snapping from that moment on, and call sp_event_context_snap_window_open(*, FALSE) when leaving the "dragging"
1283         // state. This last call will also make sure that any pending snap events will be canceled.
1284
1285         //std::cout << "sp_event_context_snap_window_open" << std::endl;
1286         if (!ec) {
1287                 if (show_debug_warnings) {
1288                         g_warning("sp_event_context_snap_window_open() has been called without providing an event context!");
1289                 }
1290                 return;
1291         }
1292
1293         if (ec->_snap_window_open == true && show_debug_warnings) {
1294                 g_warning("Snap window was already open! This is a bug, please report it.");
1295         }
1296
1297         ec->_snap_window_open = true;
1298 }
1299
1300 void sp_event_context_snap_window_closed(SPEventContext *ec, bool show_debug_warnings)
1301 {
1302         //std::cout << "sp_event_context_snap_window_closed" << std::endl;
1303         if (!ec) {
1304                 if (show_debug_warnings) {
1305                         g_warning("sp_event_context_snap_window_closed() has been called without providing an event context!");
1306                 }
1307                 return;
1308         }
1309
1310         if (ec->_snap_window_open == false && show_debug_warnings) {
1311                 g_warning("Snap window was already closed! This is a bug, please report it.");
1312         }
1313
1314         ec->_snap_window_open = false;
1315
1316         delete ec->_delayed_snap_event;
1317         ec->_delayed_snap_event = NULL;
1318 }
1319
1320
1321
1322 /*
1323   Local Variables:
1324   mode:c++
1325   c-file-style:"stroustrup"
1326   c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
1327   indent-tabs-mode:nil
1328   fill-column:99
1329   End:
1330 */
1331 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :