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 <gdk/gdkkeysyms.h>
  31 #include <gtk/gtkmain.h>
  32 #include <gtk/gtkmenu.h>
  33 #include <glibmm/i18n.h>
  34
  35 #include "display/sp-canvas.h"
  36 #include "xml/node-event-vector.h"
  37 #include "sp-cursor.h"
  38 #include "shortcuts.h"
  39 #include "desktop.h"
  40 #include "desktop-handles.h"
  41 #include "selection.h"
  42 #include "file.h"
  43 #include "interface.h"
  44 #include "macros.h"
  45 #include "tools-switch.h"
  46 #include "prefs-utils.h"
  47 #include "message-context.h"
  48 #include "gradient-drag.h"
  49 #include "object-edit.h"
  50 #include "attributes.h"
  51 #include "rubberband.h"
  52 #include "selcue.h"
  53
  54 #include "event-context.h"
  55
  56 static void sp_event_context_class_init(SPEventContextClass *klass);
  57 static void sp_event_context_init(SPEventContext *event_context);
  58 static void sp_event_context_dispose(GObject *object);
  59
  60 static void sp_event_context_private_setup(SPEventContext *ec);
  61 static gint sp_event_context_private_root_handler(SPEventContext *event_context, GdkEvent *event);
  62 static gint sp_event_context_private_item_handler(SPEventContext *event_context, SPItem *item, GdkEvent *event);
  63
  64 static void set_event_location(SPDesktop * desktop, GdkEvent * event);
  65
  66 static GObjectClass *parent_class;
  67
  68 // globals for temporary switching to selector by space
  69 static bool selector_toggled = FALSE;
  70 static int switch_selector_to = 0;
  71
  72 // globals for temporary switching to dropper by 'D'
  73 static bool dropper_toggled = FALSE;
  74 static int switch_dropper_to = 0;
  75
  76 static gint xp = 0, yp = 0; // where drag started
  77 static gint tolerance = 0;
  78 static bool within_tolerance = false;
  79
  80 // globals for keeping track of keyboard scroll events in order to accelerate
  81 static guint32 scroll_event_time = 0;
  82 static gdouble scroll_multiply = 1;
  83 static guint scroll_keyval = 0;
  84
  85 /**
  86  * Registers the SPEventContext class with Glib and returns its type number.
  87  */
  88 GType
  89 sp_event_context_get_type(void)
  90 {
  91     static GType type = 0;
  92     if (!type) {
  93         GTypeInfo info = {
  94             sizeof(SPEventContextClass),
  95             NULL, NULL,
  96             (GClassInitFunc) sp_event_context_class_init,
  97             NULL, NULL,
  98             sizeof(SPEventContext),
  99             4,
 100             (GInstanceInitFunc) sp_event_context_init,
 101             NULL,    /* value_table */
 102         };
 103         type = g_type_register_static(G_TYPE_OBJECT, "SPEventContext", &info, (GTypeFlags)0);
 104     }
 105     return type;
 106 }
 107
 108 /**
 109  * Callback to set up the SPEventContext vtable.
 110  */
 111 static void
 112 sp_event_context_class_init(SPEventContextClass *klass)
 113 {
 114     GObjectClass *object_class;
 115
 116     object_class = (GObjectClass *) klass;
 117
 118     parent_class = (GObjectClass*)g_type_class_peek_parent(klass);
 119
 120     object_class->dispose = sp_event_context_dispose;
 121
 122     klass->setup = sp_event_context_private_setup;
 123     klass->root_handler = sp_event_context_private_root_handler;
 124     klass->item_handler = sp_event_context_private_item_handler;
 125 }
 126
 127 /**
 128  * Clears all SPEventContext object members.
 129  */
 130 static void
 131 sp_event_context_init(SPEventContext *event_context)
 132 {
 133     event_context->desktop = NULL;
 134     event_context->cursor = NULL;
 135     event_context->_message_context = NULL;
 136     event_context->_selcue = NULL;
 137     event_context->_grdrag = NULL;
 138     event_context->space_panning = false;
 139 }
 140
 141 /**
 142  * Callback to free and null member variables of SPEventContext object.
 143  */
 144 static void
 145 sp_event_context_dispose(GObject *object)
 146 {
 147     SPEventContext *ec;
 148
 149     ec = SP_EVENT_CONTEXT(object);
 150
 151     if (ec->_message_context) {
 152         delete ec->_message_context;
 153     }
 154
 155     if (ec->cursor != NULL) {
 156         gdk_cursor_unref(ec->cursor);
 157         ec->cursor = NULL;
 158     }
 159
 160     if (ec->desktop) {
 161         ec->desktop = NULL;
 162     }
 163
 164     if (ec->prefs_repr) {
 165         sp_repr_remove_listener_by_data(ec->prefs_repr, ec);
 166         Inkscape::GC::release(ec->prefs_repr);
 167         ec->prefs_repr = NULL;
 168     }
 169
 170     G_OBJECT_CLASS(parent_class)->dispose(object);
 171 }
 172
 173 /**
 174  * Recreates and draws cursor on desktop related to SPEventContext.
 175  */
 176 void
 177 sp_event_context_update_cursor(SPEventContext *ec)
 178 {
 179     GtkWidget *w = GTK_WIDGET(sp_desktop_canvas(ec->desktop));
 180     if (w->window) {
 181         /* fixme: */
 182         if (ec->cursor_shape) {
 183             GdkBitmap *bitmap = NULL;
 184             GdkBitmap *mask = NULL;
 185             sp_cursor_bitmap_and_mask_from_xpm(&bitmap, &mask, ec->cursor_shape);
 186             if ((bitmap != NULL) && (mask != NULL)) {
 187                 if (ec->cursor)
 188                     gdk_cursor_unref (ec->cursor);
 189                 ec->cursor = gdk_cursor_new_from_pixmap(bitmap, mask,
 190                                                         &w->style->black,
 191                                                         &w->style->white,
 192                                                         ec->hot_x, ec->hot_y);
 193                 g_object_unref (bitmap);
 194                 g_object_unref (mask);
 195             }
 196         }
 197         gdk_window_set_cursor(w->window, ec->cursor);
 198     }
 199     ec->desktop->waiting_cursor = false;
 200 }
 201
 202 /**
 203  * Callback that gets called on initialization of SPEventContext object.
 204  * Redraws mouse cursor, at the moment.
 205  */
 206 static void
 207 sp_event_context_private_setup(SPEventContext *ec)
 208 {
 209     sp_event_context_update_cursor(ec);
 210 }
 211
 212 /**
 213  * \brief   Gobbles next key events on the queue with the same keyval and mask. Returns the number of events consumed.
 214  */
 215 gint gobble_key_events(guint keyval, gint mask)
 216 {
 217     GdkEvent *event_next;
 218     gint i = 0;
 219
 220     event_next = gdk_event_get();
 221     // while the next event is also a key notify with the same keyval and mask,
 222     while (event_next && (event_next->type == GDK_KEY_PRESS || event_next->type == GDK_KEY_RELEASE)
 223            && event_next->key.keyval == keyval
 224            && (!mask || (event_next->key.state & mask))) {
 225         if (event_next->type == GDK_KEY_PRESS)
 226             i ++;
 227         // kill it
 228         gdk_event_free(event_next);
 229         // get next
 230         event_next = gdk_event_get();
 231     }
 232     // otherwise, put it back onto the queue
 233     if (event_next) gdk_event_put(event_next);
 234
 235     return i;
 236 }
 237
 238 /**
 239  * \brief   Gobbles next motion notify events on the queue with the same mask. Returns the number of events consumed.
 240 */
 241 gint gobble_motion_events(gint mask)
 242 {
 243     GdkEvent *event_next;
 244     gint i = 0;
 245
 246     event_next = gdk_event_get();
 247     // while the next event is also a key notify with the same keyval and mask,
 248     while (event_next && event_next->type == GDK_MOTION_NOTIFY
 249            && (event_next->motion.state & mask)) {
 250         // kill it
 251         gdk_event_free(event_next);
 252         // get next
 253         event_next = gdk_event_get();
 254         i ++;
 255     }
 256     // otherwise, put it back onto the queue
 257     if (event_next) gdk_event_put(event_next);
 258
 259     return i;
 260 }
 261
 262 /**
 263  * Toggles current tool between active tool and selector tool.
 264  * Subroutine of sp_event_context_private_root_handler().
 265  */
 266 static void
 267 sp_toggle_selector(SPDesktop *dt)
 268 {
 269     if (!dt->event_context) return;
 270
 271     if (tools_isactive(dt, TOOLS_SELECT)) {
 272         if (selector_toggled) {
 273             if (switch_selector_to) tools_switch (dt, switch_selector_to);
 274             selector_toggled = FALSE;
 275         } else return;
 276     } else {
 277         selector_toggled = TRUE;
 278         switch_selector_to = tools_active(dt);
 279         tools_switch (dt, TOOLS_SELECT);
 280     }
 281 }
 282
 283 /**
 284  * Toggles current tool between active tool and selector tool.
 285  * Subroutine of sp_event_context_private_root_handler().
 286  */
 287 static void
 288 sp_toggle_dropper(SPDesktop *dt)
 289 {
 290     if (!dt->event_context) return;
 291
 292     if (tools_isactive(dt, TOOLS_DROPPER)) {
 293         if (dropper_toggled) {
 294             if (switch_dropper_to) tools_switch (dt, switch_dropper_to);
 295             dropper_toggled = FALSE;
 296         } else return;
 297     } else {
 298         dropper_toggled = TRUE;
 299         switch_dropper_to = tools_active(dt);
 300         tools_switch (dt, TOOLS_DROPPER);
 301     }
 302 }
 303
 304 /**
 305  * Calculates and keeps track of scroll acceleration.
 306  * Subroutine of sp_event_context_private_root_handler().
 307  */
 308 static gdouble accelerate_scroll(GdkEvent *event, gdouble acceleration, SPCanvas */*canvas*/)
 309 {
 310     guint32 time_diff = ((GdkEventKey *) event)->time - scroll_event_time;
 311
 312     /* key pressed within 500ms ? (1/2 second) */
 313     if (time_diff > 500 || event->key.keyval != scroll_keyval) {
 314         scroll_multiply = 1; // abort acceleration
 315     } else {
 316         scroll_multiply += acceleration; // continue acceleration
 317     }
 318
 319     scroll_event_time = ((GdkEventKey *) event)->time;
 320     scroll_keyval = event->key.keyval;
 321
 322     return scroll_multiply;
 323 }
 324
 325 /**
 326  * Main event dispatch, gets called from Gdk.
 327  */
 328 static gint sp_event_context_private_root_handler(SPEventContext *event_context, GdkEvent *event)
 329 {
 330     static NR::Point button_w;
 331     static unsigned int panning = 0;
 332     static unsigned int zoom_rb = 0;
 333
 334     SPDesktop *desktop = event_context->desktop;
 335
 336     tolerance = prefs_get_int_attribute_limited(
 337             "options.dragtolerance","value", 0, 0, 100);
 338     double const zoom_inc = prefs_get_double_attribute_limited(
 339             "options.zoomincrement", "value", M_SQRT2, 1.01, 10);
 340     double const acceleration = prefs_get_double_attribute_limited(
 341             "options.scrollingacceleration", "value", 0, 0, 6);
 342     int const key_scroll = prefs_get_int_attribute_limited(
 343             "options.keyscroll", "value", 10, 0, 1000);
 344     int const wheel_scroll = prefs_get_int_attribute_limited(
 345             "options.wheelscroll", "value", 40, 0, 1000);
 346
 347     gint ret = FALSE;
 348
 349     switch (event->type) {
 350         case GDK_2BUTTON_PRESS:
 351             if (panning) {
 352                 panning = 0;
 353                 sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate),
 354                         event->button.time);
 355                 ret = TRUE;
 356             } else {
 357                 /* sp_desktop_dialog(); */
 358             }
 359             break;
 360         case GDK_BUTTON_PRESS:
 361
 362             // save drag origin
 363             xp = (gint) event->button.x;
 364             yp = (gint) event->button.y;
 365             within_tolerance = true;
 366
 367             button_w = NR::Point(event->button.x, event->button.y);
 368
 369             switch (event->button.button) {
 370                 case 1:
 371                     if (event_context->space_panning) {
 372                         panning = 1;
 373                         sp_canvas_item_grab(SP_CANVAS_ITEM(desktop->acetate),
 374                             GDK_KEY_RELEASE_MASK | GDK_BUTTON_RELEASE_MASK | GDK_POINTER_MOTION_MASK,
 375                             NULL, event->button.time-1);
 376                         ret = TRUE;
 377                     }
 378                     break;
 379                 case 2:
 380                     if (event->button.state == GDK_SHIFT_MASK) {
 381                         zoom_rb = 2;
 382                     } else {
 383                         panning = 2;
 384                         sp_canvas_item_grab(SP_CANVAS_ITEM(desktop->acetate),
 385                             GDK_BUTTON_RELEASE_MASK | GDK_POINTER_MOTION_MASK,
 386                             NULL, event->button.time-1);
 387                     }
 388                     ret = TRUE;
 389                     break;
 390                 case 3:
 391                     if (event->button.state & GDK_SHIFT_MASK
 392                             || event->button.state & GDK_CONTROL_MASK) {
 393                         panning = 3;
 394                         sp_canvas_item_grab(SP_CANVAS_ITEM(desktop->acetate),
 395                                 GDK_BUTTON_RELEASE_MASK | GDK_POINTER_MOTION_MASK,
 396                                 NULL, event->button.time);
 397                         ret = TRUE;
 398                     } else {
 399                         sp_event_root_menu_popup(desktop, NULL, event);
 400                     }
 401                     break;
 402                 default:
 403                     break;
 404             }
 405             break;
 406         case GDK_MOTION_NOTIFY:
 407             if (panning) {
 408                 if ((panning == 2 && !(event->motion.state & GDK_BUTTON2_MASK))
 409                         || (panning == 1 && !(event->motion.state & GDK_BUTTON1_MASK))
 410                         || (panning == 3 && !(event->motion.state & GDK_BUTTON3_MASK))
 411                    ) {
 412                     /* Gdk seems to lose button release for us sometimes :-( */
 413                     panning = 0;
 414                     sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate),
 415                             event->button.time);
 416                     ret = TRUE;
 417                 } else {
 418                     if ( within_tolerance
 419                          && ( abs( (gint) event->motion.x - xp ) < tolerance )
 420                          && ( abs( (gint) event->motion.y - yp ) < tolerance ))
 421                     {
 422                         // do not drag if we're within tolerance from origin
 423                         break;
 424                     }
 425                     // Once the user has moved farther than tolerance from
 426                     // the original location (indicating they intend to move
 427                     // the object, not click), then always process the motion
 428                     // notify coordinates as given (no snapping back to origin)
 429                     within_tolerance = false;
 430
 431                     // gobble subsequent motion events to prevent "sticking"
 432                     // when scrolling is slow
 433                     gobble_motion_events(panning == 2 ?
 434                                          GDK_BUTTON2_MASK :
 435                                          (panning == 1 ? GDK_BUTTON1_MASK : GDK_BUTTON3_MASK));
 436
 437                     NR::Point const motion_w(event->motion.x, event->motion.y);
 438                     NR::Point const moved_w( motion_w - button_w );
 439                     event_context->desktop->scroll_world(moved_w, true); // we're still scrolling, do not redraw
 440                     ret = TRUE;
 441                 }
 442             } else if (zoom_rb) {
 443                 NR::Point const motion_w(event->motion.x, event->motion.y);
 444                 NR::Point const motion_dt(desktop->w2d(motion_w));
 445
 446                 if ( within_tolerance
 447                      && ( abs( (gint) event->motion.x - xp ) < tolerance )
 448                      && ( abs( (gint) event->motion.y - yp ) < tolerance ) ) {
 449                     break; // do not drag if we're within tolerance from origin
 450                 }
 451                 // Once the user has moved farther than tolerance from the original location
 452                 // (indicating they intend to move the object, not click), then always process the
 453                 // motion notify coordinates as given (no snapping back to origin)
 454                 within_tolerance = false;
 455
 456                 if (Inkscape::Rubberband::get()->is_started()) {
 457                     Inkscape::Rubberband::get()->move(motion_dt);
 458                 } else {
 459                     Inkscape::Rubberband::get()->start(desktop, motion_dt);
 460                 }
 461                 if (zoom_rb == 2)
 462                     gobble_motion_events(GDK_BUTTON2_MASK);
 463             }
 464             break;
 465         case GDK_BUTTON_RELEASE:
 466             xp = yp = 0;
 467             if (within_tolerance && (panning || zoom_rb)) {
 468                 zoom_rb = 0;
 469                 if (panning) {
 470                     panning = 0;
 471                     sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate),
 472                                       event->button.time);
 473                 }
 474                 NR::Point const event_w(event->button.x, event->button.y);
 475                 NR::Point const event_dt(desktop->w2d(event_w));
 476                 desktop->zoom_relative_keep_point(event_dt,
 477                           (event->button.state & GDK_SHIFT_MASK) ? 1/zoom_inc : zoom_inc);
 478                 desktop->updateNow();
 479                 ret = TRUE;
 480             } else if (panning == event->button.button) {
 481                 panning = 0;
 482                 sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate),
 483                                       event->button.time);
 484
 485                 // in slow complex drawings, some of the motion events are lost;
 486                 // to make up for this, we scroll it once again to the button-up event coordinates
 487                 // (i.e. canvas will always get scrolled all the way to the mouse release point,
 488                 // even if few intermediate steps were visible)
 489                 NR::Point const motion_w(event->button.x, event->button.y);
 490                 NR::Point const moved_w( motion_w - button_w );
 491                 event_context->desktop->scroll_world(moved_w);
 492                 desktop->updateNow();
 493                 ret = TRUE;
 494             } else if (zoom_rb == event->button.button) {
 495                 zoom_rb = 0;
 496                 NR::Maybe<NR::Rect> const b = Inkscape::Rubberband::get()->getRectangle();
 497                 Inkscape::Rubberband::get()->stop();
 498                 if (b && !within_tolerance) {
 499                     desktop->set_display_area(*b, 10);
 500                 }
 501                 ret = TRUE;
 502             }
 503             break;
 504         case GDK_KEY_PRESS:
 505             switch (get_group0_keyval(&event->key)) {
 506                 // GDK insists on stealing these keys (F1 for no idea what, tab for cycling widgets
 507                 // in the editing window). So we resteal them back and run our regular shortcut
 508                 // invoker on them.
 509                 unsigned int shortcut;
 510                 case GDK_Tab:
 511                 case GDK_ISO_Left_Tab:
 512                 case GDK_F1:
 513                     shortcut = get_group0_keyval(&event->key);
 514                     if (event->key.state & GDK_SHIFT_MASK)
 515                         shortcut |= SP_SHORTCUT_SHIFT_MASK;
 516                     if (event->key.state & GDK_CONTROL_MASK)
 517                         shortcut |= SP_SHORTCUT_CONTROL_MASK;
 518                     if (event->key.state & GDK_MOD1_MASK)
 519                         shortcut |= SP_SHORTCUT_ALT_MASK;
 520                     ret = sp_shortcut_invoke(shortcut, desktop);
 521                     break;
 522
 523                 case GDK_D:
 524                 case GDK_d:
 525                     sp_toggle_dropper(desktop);
 526                     ret = TRUE;
 527                     break;
 528                 case GDK_W:
 529                 case GDK_w:
 530                 case GDK_F4:
 531                     /* Close view */
 532                     if (MOD__CTRL_ONLY) {
 533                         sp_ui_close_view(NULL);
 534                         ret = TRUE;
 535                     }
 536                     break;
 537                 case GDK_Left: // Ctrl Left
 538                 case GDK_KP_Left:
 539                 case GDK_KP_4:
 540                     if (MOD__CTRL_ONLY) {
 541                         int i = (int) floor(key_scroll * accelerate_scroll(event, acceleration, sp_desktop_canvas(desktop)));
 542                         gobble_key_events(get_group0_keyval(&event->key),
 543                                 GDK_CONTROL_MASK);
 544                         event_context->desktop->scroll_world(i, 0);
 545                         ret = TRUE;
 546                     }
 547                     break;
 548                 case GDK_Up: // Ctrl Up
 549                 case GDK_KP_Up:
 550                 case GDK_KP_8:
 551                     if (MOD__CTRL_ONLY) {
 552                         int i = (int) floor(key_scroll * accelerate_scroll(event, acceleration, sp_desktop_canvas(desktop)));
 553                         gobble_key_events(get_group0_keyval(&event->key),
 554                                 GDK_CONTROL_MASK);
 555                         event_context->desktop->scroll_world(0, i);
 556                         ret = TRUE;
 557                     }
 558                     break;
 559                 case GDK_Right: // Ctrl Right
 560                 case GDK_KP_Right:
 561                 case GDK_KP_6:
 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_Down: // Ctrl Down
 571                 case GDK_KP_Down:
 572                 case GDK_KP_2:
 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_F10:
 582                     if (MOD__SHIFT_ONLY) {
 583                         sp_event_root_menu_popup(desktop, NULL, event);
 584                         ret= TRUE;
 585                     }
 586                     break;
 587                 case GDK_space:
 588                     if (prefs_get_int_attribute("options.spacepans","value", 0) == 1) {
 589                         event_context->space_panning = true;
 590                         event_context->_message_context->set(Inkscape::INFORMATION_MESSAGE, _("<b>Space+mouse drag</b> to pan canvas"));
 591                         ret= TRUE;
 592                     } else {
 593                         sp_toggle_selector(desktop);
 594                         ret= TRUE;
 595                     }
 596                     break;
 597                 case GDK_z:
 598                 case GDK_Z:
 599                     if (MOD__ALT_ONLY) {
 600                         desktop->zoom_grab_focus();
 601                         ret = TRUE;
 602                     }
 603                     break;
 604                 default:
 605                     break;
 606             }
 607             break;
 608         case GDK_KEY_RELEASE:
 609             switch (get_group0_keyval(&event->key)) {
 610                 case GDK_space:
 611                     if (event_context->space_panning) {
 612                         event_context->space_panning = false;
 613                         event_context->_message_context->clear();
 614                         if (panning == 1) {
 615                             panning = 0;
 616                             sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate),
 617                                   event->key.time);
 618                             desktop->updateNow();
 619                         }
 620                         ret= TRUE;
 621                     }
 622                     break;
 623                 default:
 624                     break;
 625             }
 626             break;
 627         case GDK_SCROLL:
 628         {
 629             bool ctrl = (event->scroll.state & GDK_CONTROL_MASK);
 630             bool wheelzooms = (prefs_get_int_attribute("options.wheelzooms","value", 0) == 1);
 631             /* shift + wheel, pan left--right */
 632             if (event->scroll.state & GDK_SHIFT_MASK) {
 633                 switch (event->scroll.direction) {
 634                     case GDK_SCROLL_UP:
 635                         desktop->scroll_world(wheel_scroll, 0);
 636                         break;
 637                     case GDK_SCROLL_DOWN:
 638                         desktop->scroll_world(-wheel_scroll, 0);
 639                         break;
 640                     default:
 641                         break;
 642                 }
 643
 644                 /* ctrl + wheel, zoom in--out */
 645             } else if ((ctrl && !wheelzooms) || (!ctrl && wheelzooms)) {
 646                 double rel_zoom;
 647                 switch (event->scroll.direction) {
 648                     case GDK_SCROLL_UP:
 649                         rel_zoom = zoom_inc;
 650                         break;
 651                     case GDK_SCROLL_DOWN:
 652                         rel_zoom = 1 / zoom_inc;
 653                         break;
 654                     default:
 655                         rel_zoom = 0.0;
 656                         break;
 657                 }
 658                 if (rel_zoom != 0.0) {
 659                     NR::Point const scroll_dt = desktop->point();
 660                     desktop->zoom_relative_keep_point(scroll_dt, rel_zoom);
 661                 }
 662
 663                 /* no modifier, pan up--down (left--right on multiwheel mice?) */
 664             } else {
 665                 switch (event->scroll.direction) {
 666                     case GDK_SCROLL_UP:
 667                         desktop->scroll_world(0, wheel_scroll);
 668                         break;
 669                     case GDK_SCROLL_DOWN:
 670                         desktop->scroll_world(0, -wheel_scroll);
 671                         break;
 672                     case GDK_SCROLL_LEFT:
 673                         desktop->scroll_world(wheel_scroll, 0);
 674                         break;
 675                     case GDK_SCROLL_RIGHT:
 676                         desktop->scroll_world(-wheel_scroll, 0);
 677                         break;
 678                 }
 679             }
 680             break;
 681         }
 682         default:
 683             break;
 684     }
 685
 686     return ret;
 687 }
 688
 689 /**
 690  * Handles item specific events. Gets called from Gdk.
 691  *
 692  * Only reacts to right mouse button at the moment.
 693  * \todo Fixme: do context sensitive popup menu on items.
 694  */
 695 gint
 696 sp_event_context_private_item_handler(SPEventContext *ec, SPItem *item, GdkEvent *event)
 697 {
 698     int ret = FALSE;
 699
 700     switch (event->type) {
 701         case GDK_BUTTON_PRESS:
 702             if ((event->button.button == 3)
 703                     && !(event->button.state & GDK_SHIFT_MASK || event->button.state & GDK_CONTROL_MASK)) {
 704                 sp_event_root_menu_popup(ec->desktop, item, event);
 705                 ret = TRUE;
 706             }
 707             break;
 708         default:
 709             break;
 710     }
 711
 712     return ret;
 713 }
 714
 715 /**
 716  * Gets called when attribute changes value.
 717  */
 718 static void
 719 sp_ec_repr_attr_changed(Inkscape::XML::Node */*prefs_repr*/, gchar const *key, gchar const */*oldval*/, gchar const *newval,
 720                         bool /*is_interactive*/, gpointer data)
 721 {
 722     SPEventContext *ec;
 723
 724     ec = SP_EVENT_CONTEXT(data);
 725
 726     if (((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->set) {
 727         ((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->set(ec, key, newval);
 728     }
 729 }
 730
 731 Inkscape::XML::NodeEventVector sp_ec_event_vector = {
 732     NULL, /* Child added */
 733     NULL, /* Child removed */
 734     sp_ec_repr_attr_changed,
 735     NULL, /* Content changed */
 736     NULL /* Order changed */
 737 };
 738
 739 /**
 740  * Creates new SPEventContext object and calls its virtual setup() function.
 741  */
 742 SPEventContext *
 743 sp_event_context_new(GType type, SPDesktop *desktop, Inkscape::XML::Node *prefs_repr, unsigned int key)
 744 {
 745     g_return_val_if_fail(g_type_is_a(type, SP_TYPE_EVENT_CONTEXT), NULL);
 746     g_return_val_if_fail(desktop != NULL, NULL);
 747
 748     SPEventContext *const ec = (SPEventContext*)g_object_new(type, NULL);
 749
 750     ec->desktop = desktop;
 751     ec->_message_context = new Inkscape::MessageContext(desktop->messageStack());
 752     ec->key = key;
 753     ec->prefs_repr = prefs_repr;
 754     if (ec->prefs_repr) {
 755         Inkscape::GC::anchor(ec->prefs_repr);
 756         sp_repr_add_listener(ec->prefs_repr, &sp_ec_event_vector, ec);
 757     }
 758
 759     if (((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->setup)
 760         ((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->setup(ec);
 761
 762     return ec;
 763 }
 764
 765 /**
 766  * Finishes SPEventContext.
 767  */
 768 void
 769 sp_event_context_finish(SPEventContext *ec)
 770 {
 771     g_return_if_fail(ec != NULL);
 772     g_return_if_fail(SP_IS_EVENT_CONTEXT(ec));
 773
 774     ec->enableSelectionCue(false);
 775
 776     if (ec->next) {
 777         g_warning("Finishing event context with active link\n");
 778     }
 779
 780     if (((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->finish)
 781         ((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->finish(ec);
 782 }
 783
 784 //-------------------------------member functions
 785
 786 /**
 787  * Enables/disables the SPEventContext's SelCue.
 788  */
 789 void SPEventContext::enableSelectionCue(bool enable) {
 790     if (enable) {
 791         if (!_selcue) {
 792             _selcue = new Inkscape::SelCue(desktop);
 793         }
 794     } else {
 795         delete _selcue;
 796         _selcue = NULL;
 797     }
 798 }
 799
 800 /**
 801  * Enables/disables the SPEventContext's GrDrag.
 802  */
 803 void SPEventContext::enableGrDrag(bool enable) {
 804     if (enable) {
 805         if (!_grdrag) {
 806             _grdrag = new GrDrag(desktop);
 807         }
 808     } else {
 809         if (_grdrag) {
 810             delete _grdrag;
 811             _grdrag = NULL;
 812         }
 813     }
 814 }
 815
 816 /**
 817  * Calls virtual set() function of SPEventContext.
 818  */
 819 void
 820 sp_event_context_read(SPEventContext *ec, gchar const *key)
 821 {
 822     g_return_if_fail(ec != NULL);
 823     g_return_if_fail(SP_IS_EVENT_CONTEXT(ec));
 824     g_return_if_fail(key != NULL);
 825
 826     if (ec->prefs_repr) {
 827         gchar const *val = ec->prefs_repr->attribute(key);
 828         if (((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->set)
 829             ((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->set(ec, key, val);
 830     }
 831 }
 832
 833 /**
 834  * Calls virtual activate() function of SPEventContext.
 835  */
 836 void
 837 sp_event_context_activate(SPEventContext *ec)
 838 {
 839     g_return_if_fail(ec != NULL);
 840     g_return_if_fail(SP_IS_EVENT_CONTEXT(ec));
 841
 842     if (((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->activate)
 843         ((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->activate(ec);
 844 }
 845
 846 /**
 847  * Calls virtual deactivate() function of SPEventContext.
 848  */
 849 void
 850 sp_event_context_deactivate(SPEventContext *ec)
 851 {
 852     g_return_if_fail(ec != NULL);
 853     g_return_if_fail(SP_IS_EVENT_CONTEXT(ec));
 854
 855     if (((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->deactivate)
 856         ((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->deactivate(ec);
 857 }
 858
 859 /**
 860  * Calls virtual root_handler(), the main event handling function.
 861  */
 862 gint
 863 sp_event_context_root_handler(SPEventContext * event_context, GdkEvent * event)
 864 {
 865     gint ret;
 866
 867     ret = ((SPEventContextClass *) G_OBJECT_GET_CLASS(event_context))->root_handler(event_context, event);
 868
 869     set_event_location(event_context->desktop, event);
 870
 871     return ret;
 872 }
 873
 874 /**
 875  * Calls virtual item_handler(), the item event handling function.
 876  */
 877 gint
 878 sp_event_context_item_handler(SPEventContext * event_context, SPItem * item, GdkEvent * event)
 879 {
 880     gint ret;
 881
 882     ret = ((SPEventContextClass *) G_OBJECT_GET_CLASS(event_context))->item_handler(event_context, item, event);
 883
 884     if (! ret) {
 885         ret = sp_event_context_root_handler(event_context, event);
 886     } else {
 887         set_event_location(event_context->desktop, event);
 888     }
 889
 890     return ret;
 891 }
 892
 893 /**
 894  * Emits 'position_set' signal on desktop and shows coordinates on status bar.
 895  */
 896 static void set_event_location(SPDesktop *desktop, GdkEvent *event)
 897 {
 898     if (event->type != GDK_MOTION_NOTIFY) {
 899         return;
 900     }
 901
 902     NR::Point const button_w(event->button.x, event->button.y);
 903     NR::Point const button_dt(desktop->w2d(button_w));
 904     desktop-> setPosition (button_dt);
 905     desktop->set_coordinate_status(button_dt);
 906 }
 907
 908 //-------------------------------------------------------------------
 909 /**
 910  * Create popup menu and tell Gtk to show it.
 911  */
 912 void
 913 sp_event_root_menu_popup(SPDesktop *desktop, SPItem *item, GdkEvent *event)
 914 {
 915     GtkWidget *menu;
 916
 917     /* fixme: This is not what I want but works for now (Lauris) */
 918     if (event->type == GDK_KEY_PRESS) {
 919         item = sp_desktop_selection(desktop)->singleItem();
 920     }
 921     menu = sp_ui_context_menu(desktop, item);
 922     gtk_widget_show(menu);
 923
 924     switch (event->type) {
 925         case GDK_BUTTON_PRESS:
 926             gtk_menu_popup(GTK_MENU(menu), NULL, NULL, 0, NULL, event->button.button, event->button.time);
 927             break;
 928         case GDK_KEY_PRESS:
 929             gtk_menu_popup(GTK_MENU(menu), NULL, NULL, 0, NULL, 0, event->key.time);
 930             break;
 931         default:
 932             break;
 933     }
 934 }
 935
 936 /**
 937  * Show tool context specific modifier tip.
 938  */
 939 void
 940 sp_event_show_modifier_tip(Inkscape::MessageContext *message_context,
 941         GdkEvent *event, gchar const *ctrl_tip, gchar const *shift_tip,
 942         gchar const *alt_tip)
 943 {
 944     guint keyval = get_group0_keyval(&event->key);
 945
 946     bool ctrl = ctrl_tip && (MOD__CTRL
 947             || (keyval == GDK_Control_L)
 948             || (keyval == GDK_Control_R));
 949     bool shift = shift_tip
 950         && (MOD__SHIFT || (keyval == GDK_Shift_L) || (keyval == GDK_Shift_R));
 951     bool alt = alt_tip
 952         && (MOD__ALT
 953                 || (keyval == GDK_Alt_L)
 954                 || (keyval == GDK_Alt_R)
 955                 || (keyval == GDK_Meta_L)
 956                 || (keyval == GDK_Meta_R));
 957
 958     gchar *tip = g_strdup_printf("%s%s%s%s%s",
 959                                  ( ctrl ? ctrl_tip : "" ),
 960                                  ( ctrl && (shift || alt) ? "; " : "" ),
 961                                  ( shift ? shift_tip : "" ),
 962                                  ( (ctrl || shift) && alt ? "; " : "" ),
 963                                  ( alt ? alt_tip : "" ));
 964
 965     if (strlen(tip) > 0) {
 966         message_context->flash(Inkscape::INFORMATION_MESSAGE, tip);
 967     }
 968
 969     g_free(tip);
 970 }
 971
 972 /**
 973  * Return the keyval corresponding to the key event in group 0, i.e.,
 974  * in the main (English) layout.
 975  *
 976  * Use this instead of simply event->keyval, so that your keyboard shortcuts
 977  * work regardless of layouts (e.g., in Cyrillic).
 978  */
 979 guint
 980 get_group0_keyval(GdkEventKey *event)
 981 {
 982     guint keyval = 0;
 983     gdk_keymap_translate_keyboard_state(
 984             gdk_keymap_get_for_display(gdk_display_get_default()),
 985             event->hardware_keycode,
 986             (GdkModifierType) event->state,
 987             0   /*event->key.group*/,
 988             &keyval, NULL, NULL, NULL);
 989     return keyval;
 990 }
 991
 992 /**
 993  * Returns item at point p in desktop.
 994  *
 995  * If state includes alt key mask, cyclically selects under; honors
 996  * into_groups.
 997  */
 998 SPItem *
 999 sp_event_context_find_item (SPDesktop *desktop, NR::Point const p,
1000         bool select_under, bool into_groups)
1001 {
1002     SPItem *item;
1003
1004     if (select_under) {
1005         SPItem *selected_at_point =
1006             desktop->item_from_list_at_point_bottom (desktop->selection->itemList(), p);
1007         item = desktop->item_at_point(p, into_groups, selected_at_point);
1008         if (item == NULL) { // we may have reached bottom, flip over to the top
1009             item = desktop->item_at_point(p, into_groups, NULL);
1010         }
1011     } else
1012         item = desktop->item_at_point(p, into_groups, NULL);
1013
1014     return item;
1015 }
1016
1017 /**
1018  * Returns item if it is under point p in desktop, at any depth; otherwise returns NULL.
1019  *
1020  * Honors into_groups.
1021  */
1022 SPItem *
1023 sp_event_context_over_item (SPDesktop *desktop, SPItem *item, NR::Point const p)
1024 {
1025     GSList *temp = NULL;
1026     temp = g_slist_prepend (temp, item);
1027     SPItem *item_at_point = desktop->item_from_list_at_point_bottom (temp, p);
1028     g_slist_free (temp);
1029
1030     return item_at_point;
1031 }
1032
1033 /**
1034  * Called when SPEventContext subclass node attribute changed.
1035  */
1036 void
1037 ec_shape_event_attr_changed(Inkscape::XML::Node */*shape_repr*/, gchar const *name,
1038                             gchar const */*old_value*/, gchar const */*new_value*/,
1039                             bool const /*is_interactive*/, gpointer const data)
1040 {
1041     if (!name
1042             || !strcmp(name, "style")
1043             || SP_ATTRIBUTE_IS_CSS(sp_attribute_lookup(name))) {
1044         // no need to regenrate knotholder if only style changed
1045         return;
1046     }
1047
1048     SPEventContext *ec = SP_EVENT_CONTEXT(data);
1049
1050     if (ec->shape_knot_holder) {
1051         sp_knot_holder_destroy(ec->shape_knot_holder);
1052     }
1053     ec->shape_knot_holder = NULL;
1054
1055     SPDesktop *desktop = ec->desktop;
1056
1057     SPItem *item = sp_desktop_selection(desktop)->singleItem();
1058
1059     if (item) {
1060         ec->shape_knot_holder = sp_item_knot_holder(item, desktop);
1061     }
1062 }
1063
1064
1065 /*
1066   Local Variables:
1067   mode:c++
1068   c-file-style:"stroustrup"
1069   c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
1070   indent-tabs-mode:nil
1071   fill-column:99
1072   End:
1073 */
1074 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :