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 dropper 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                     if (!MOD__SHIFT && !MOD__CTRL && !MOD__ALT) {
 526                         sp_toggle_dropper(desktop);
 527                         ret = TRUE;
 528                     }
 529                     break;
 530                 case GDK_W:
 531                 case GDK_w:
 532                 case GDK_F4:
 533                     /* Close view */
 534                     if (MOD__CTRL_ONLY) {
 535                         sp_ui_close_view(NULL);
 536                         ret = TRUE;
 537                     }
 538                     break;
 539                 case GDK_Left: // Ctrl Left
 540                 case GDK_KP_Left:
 541                 case GDK_KP_4:
 542                     if (MOD__CTRL_ONLY) {
 543                         int i = (int) floor(key_scroll * accelerate_scroll(event, acceleration, sp_desktop_canvas(desktop)));
 544                         gobble_key_events(get_group0_keyval(&event->key),
 545                                 GDK_CONTROL_MASK);
 546                         event_context->desktop->scroll_world(i, 0);
 547                         ret = TRUE;
 548                     }
 549                     break;
 550                 case GDK_Up: // Ctrl Up
 551                 case GDK_KP_Up:
 552                 case GDK_KP_8:
 553                     if (MOD__CTRL_ONLY) {
 554                         int i = (int) floor(key_scroll * accelerate_scroll(event, acceleration, sp_desktop_canvas(desktop)));
 555                         gobble_key_events(get_group0_keyval(&event->key),
 556                                 GDK_CONTROL_MASK);
 557                         event_context->desktop->scroll_world(0, i);
 558                         ret = TRUE;
 559                     }
 560                     break;
 561                 case GDK_Right: // Ctrl Right
 562                 case GDK_KP_Right:
 563                 case GDK_KP_6:
 564                     if (MOD__CTRL_ONLY) {
 565                         int i = (int) floor(key_scroll * accelerate_scroll(event, acceleration, sp_desktop_canvas(desktop)));
 566                         gobble_key_events(get_group0_keyval(&event->key),
 567                                 GDK_CONTROL_MASK);
 568                         event_context->desktop->scroll_world(-i, 0);
 569                         ret = TRUE;
 570                     }
 571                     break;
 572                 case GDK_Down: // Ctrl Down
 573                 case GDK_KP_Down:
 574                 case GDK_KP_2:
 575                     if (MOD__CTRL_ONLY) {
 576                         int i = (int) floor(key_scroll * accelerate_scroll(event, acceleration, sp_desktop_canvas(desktop)));
 577                         gobble_key_events(get_group0_keyval(&event->key),
 578                                 GDK_CONTROL_MASK);
 579                         event_context->desktop->scroll_world(0, -i);
 580                         ret = TRUE;
 581                     }
 582                     break;
 583                 case GDK_F10:
 584                     if (MOD__SHIFT_ONLY) {
 585                         sp_event_root_menu_popup(desktop, NULL, event);
 586                         ret= TRUE;
 587                     }
 588                     break;
 589                 case GDK_space:
 590                     if (prefs_get_int_attribute("options.spacepans","value", 0) == 1) {
 591                         event_context->space_panning = true;
 592                         event_context->_message_context->set(Inkscape::INFORMATION_MESSAGE, _("<b>Space+mouse drag</b> to pan canvas"));
 593                         ret= TRUE;
 594                     } else {
 595                         sp_toggle_selector(desktop);
 596                         ret= TRUE;
 597                     }
 598                     break;
 599                 case GDK_z:
 600                 case GDK_Z:
 601                     if (MOD__ALT_ONLY) {
 602                         desktop->zoom_grab_focus();
 603                         ret = TRUE;
 604                     }
 605                     break;
 606                 default:
 607                     break;
 608             }
 609             break;
 610         case GDK_KEY_RELEASE:
 611             switch (get_group0_keyval(&event->key)) {
 612                 case GDK_space:
 613                     if (event_context->space_panning) {
 614                         event_context->space_panning = false;
 615                         event_context->_message_context->clear();
 616                         if (panning == 1) {
 617                             panning = 0;
 618                             sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate),
 619                                   event->key.time);
 620                             desktop->updateNow();
 621                         }
 622                         ret= TRUE;
 623                     }
 624                     break;
 625                 default:
 626                     break;
 627             }
 628             break;
 629         case GDK_SCROLL:
 630         {
 631             bool ctrl = (event->scroll.state & GDK_CONTROL_MASK);
 632             bool wheelzooms = (prefs_get_int_attribute("options.wheelzooms","value", 0) == 1);
 633             /* shift + wheel, pan left--right */
 634             if (event->scroll.state & GDK_SHIFT_MASK) {
 635                 switch (event->scroll.direction) {
 636                     case GDK_SCROLL_UP:
 637                         desktop->scroll_world(wheel_scroll, 0);
 638                         break;
 639                     case GDK_SCROLL_DOWN:
 640                         desktop->scroll_world(-wheel_scroll, 0);
 641                         break;
 642                     default:
 643                         break;
 644                 }
 645
 646                 /* ctrl + wheel, zoom in--out */
 647             } else if ((ctrl && !wheelzooms) || (!ctrl && wheelzooms)) {
 648                 double rel_zoom;
 649                 switch (event->scroll.direction) {
 650                     case GDK_SCROLL_UP:
 651                         rel_zoom = zoom_inc;
 652                         break;
 653                     case GDK_SCROLL_DOWN:
 654                         rel_zoom = 1 / zoom_inc;
 655                         break;
 656                     default:
 657                         rel_zoom = 0.0;
 658                         break;
 659                 }
 660                 if (rel_zoom != 0.0) {
 661                     NR::Point const scroll_dt = desktop->point();
 662                     desktop->zoom_relative_keep_point(scroll_dt, rel_zoom);
 663                 }
 664
 665                 /* no modifier, pan up--down (left--right on multiwheel mice?) */
 666             } else {
 667                 switch (event->scroll.direction) {
 668                     case GDK_SCROLL_UP:
 669                         desktop->scroll_world(0, wheel_scroll);
 670                         break;
 671                     case GDK_SCROLL_DOWN:
 672                         desktop->scroll_world(0, -wheel_scroll);
 673                         break;
 674                     case GDK_SCROLL_LEFT:
 675                         desktop->scroll_world(wheel_scroll, 0);
 676                         break;
 677                     case GDK_SCROLL_RIGHT:
 678                         desktop->scroll_world(-wheel_scroll, 0);
 679                         break;
 680                 }
 681             }
 682             break;
 683         }
 684         default:
 685             break;
 686     }
 687
 688     return ret;
 689 }
 690
 691 /**
 692  * Handles item specific events. Gets called from Gdk.
 693  *
 694  * Only reacts to right mouse button at the moment.
 695  * \todo Fixme: do context sensitive popup menu on items.
 696  */
 697 gint
 698 sp_event_context_private_item_handler(SPEventContext *ec, SPItem *item, GdkEvent *event)
 699 {
 700     int ret = FALSE;
 701
 702     switch (event->type) {
 703         case GDK_BUTTON_PRESS:
 704             if ((event->button.button == 3)
 705                     && !(event->button.state & GDK_SHIFT_MASK || event->button.state & GDK_CONTROL_MASK)) {
 706                 sp_event_root_menu_popup(ec->desktop, item, event);
 707                 ret = TRUE;
 708             }
 709             break;
 710         default:
 711             break;
 712     }
 713
 714     return ret;
 715 }
 716
 717 /**
 718  * Gets called when attribute changes value.
 719  */
 720 static void
 721 sp_ec_repr_attr_changed(Inkscape::XML::Node */*prefs_repr*/, gchar const *key, gchar const */*oldval*/, gchar const *newval,
 722                         bool /*is_interactive*/, gpointer data)
 723 {
 724     SPEventContext *ec;
 725
 726     ec = SP_EVENT_CONTEXT(data);
 727
 728     if (((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->set) {
 729         ((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->set(ec, key, newval);
 730     }
 731 }
 732
 733 Inkscape::XML::NodeEventVector sp_ec_event_vector = {
 734     NULL, /* Child added */
 735     NULL, /* Child removed */
 736     sp_ec_repr_attr_changed,
 737     NULL, /* Content changed */
 738     NULL /* Order changed */
 739 };
 740
 741 /**
 742  * Creates new SPEventContext object and calls its virtual setup() function.
 743  */
 744 SPEventContext *
 745 sp_event_context_new(GType type, SPDesktop *desktop, Inkscape::XML::Node *prefs_repr, unsigned int key)
 746 {
 747     g_return_val_if_fail(g_type_is_a(type, SP_TYPE_EVENT_CONTEXT), NULL);
 748     g_return_val_if_fail(desktop != NULL, NULL);
 749
 750     SPEventContext *const ec = (SPEventContext*)g_object_new(type, NULL);
 751
 752     ec->desktop = desktop;
 753     ec->_message_context = new Inkscape::MessageContext(desktop->messageStack());
 754     ec->key = key;
 755     ec->prefs_repr = prefs_repr;
 756     if (ec->prefs_repr) {
 757         Inkscape::GC::anchor(ec->prefs_repr);
 758         sp_repr_add_listener(ec->prefs_repr, &sp_ec_event_vector, ec);
 759     }
 760
 761     if (((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->setup)
 762         ((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->setup(ec);
 763
 764     return ec;
 765 }
 766
 767 /**
 768  * Finishes SPEventContext.
 769  */
 770 void
 771 sp_event_context_finish(SPEventContext *ec)
 772 {
 773     g_return_if_fail(ec != NULL);
 774     g_return_if_fail(SP_IS_EVENT_CONTEXT(ec));
 775
 776     ec->enableSelectionCue(false);
 777
 778     if (ec->next) {
 779         g_warning("Finishing event context with active link\n");
 780     }
 781
 782     if (((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->finish)
 783         ((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->finish(ec);
 784 }
 785
 786 //-------------------------------member functions
 787
 788 /**
 789  * Enables/disables the SPEventContext's SelCue.
 790  */
 791 void SPEventContext::enableSelectionCue(bool enable) {
 792     if (enable) {
 793         if (!_selcue) {
 794             _selcue = new Inkscape::SelCue(desktop);
 795         }
 796     } else {
 797         delete _selcue;
 798         _selcue = NULL;
 799     }
 800 }
 801
 802 /**
 803  * Enables/disables the SPEventContext's GrDrag.
 804  */
 805 void SPEventContext::enableGrDrag(bool enable) {
 806     if (enable) {
 807         if (!_grdrag) {
 808             _grdrag = new GrDrag(desktop);
 809         }
 810     } else {
 811         if (_grdrag) {
 812             delete _grdrag;
 813             _grdrag = NULL;
 814         }
 815     }
 816 }
 817
 818 /**
 819  * Calls virtual set() function of SPEventContext.
 820  */
 821 void
 822 sp_event_context_read(SPEventContext *ec, gchar const *key)
 823 {
 824     g_return_if_fail(ec != NULL);
 825     g_return_if_fail(SP_IS_EVENT_CONTEXT(ec));
 826     g_return_if_fail(key != NULL);
 827
 828     if (ec->prefs_repr) {
 829         gchar const *val = ec->prefs_repr->attribute(key);
 830         if (((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->set)
 831             ((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->set(ec, key, val);
 832     }
 833 }
 834
 835 /**
 836  * Calls virtual activate() function of SPEventContext.
 837  */
 838 void
 839 sp_event_context_activate(SPEventContext *ec)
 840 {
 841     g_return_if_fail(ec != NULL);
 842     g_return_if_fail(SP_IS_EVENT_CONTEXT(ec));
 843
 844     if (((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->activate)
 845         ((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->activate(ec);
 846 }
 847
 848 /**
 849  * Calls virtual deactivate() function of SPEventContext.
 850  */
 851 void
 852 sp_event_context_deactivate(SPEventContext *ec)
 853 {
 854     g_return_if_fail(ec != NULL);
 855     g_return_if_fail(SP_IS_EVENT_CONTEXT(ec));
 856
 857     if (((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->deactivate)
 858         ((SPEventContextClass *) G_OBJECT_GET_CLASS(ec))->deactivate(ec);
 859 }
 860
 861 /**
 862  * Calls virtual root_handler(), the main event handling function.
 863  */
 864 gint
 865 sp_event_context_root_handler(SPEventContext * event_context, GdkEvent * event)
 866 {
 867     gint ret;
 868
 869     ret = ((SPEventContextClass *) G_OBJECT_GET_CLASS(event_context))->root_handler(event_context, event);
 870
 871     set_event_location(event_context->desktop, event);
 872
 873     return ret;
 874 }
 875
 876 /**
 877  * Calls virtual item_handler(), the item event handling function.
 878  */
 879 gint
 880 sp_event_context_item_handler(SPEventContext * event_context, SPItem * item, GdkEvent * event)
 881 {
 882     gint ret;
 883
 884     ret = ((SPEventContextClass *) G_OBJECT_GET_CLASS(event_context))->item_handler(event_context, item, event);
 885
 886     if (! ret) {
 887         ret = sp_event_context_root_handler(event_context, event);
 888     } else {
 889         set_event_location(event_context->desktop, event);
 890     }
 891
 892     return ret;
 893 }
 894
 895 /**
 896  * Emits 'position_set' signal on desktop and shows coordinates on status bar.
 897  */
 898 static void set_event_location(SPDesktop *desktop, GdkEvent *event)
 899 {
 900     if (event->type != GDK_MOTION_NOTIFY) {
 901         return;
 902     }
 903
 904     NR::Point const button_w(event->button.x, event->button.y);
 905     NR::Point const button_dt(desktop->w2d(button_w));
 906     desktop-> setPosition (button_dt);
 907     desktop->set_coordinate_status(button_dt);
 908 }
 909
 910 //-------------------------------------------------------------------
 911 /**
 912  * Create popup menu and tell Gtk to show it.
 913  */
 914 void
 915 sp_event_root_menu_popup(SPDesktop *desktop, SPItem *item, GdkEvent *event)
 916 {
 917     GtkWidget *menu;
 918
 919     /* fixme: This is not what I want but works for now (Lauris) */
 920     if (event->type == GDK_KEY_PRESS) {
 921         item = sp_desktop_selection(desktop)->singleItem();
 922     }
 923     menu = sp_ui_context_menu(desktop, item);
 924     gtk_widget_show(menu);
 925
 926     switch (event->type) {
 927         case GDK_BUTTON_PRESS:
 928             gtk_menu_popup(GTK_MENU(menu), NULL, NULL, 0, NULL, event->button.button, event->button.time);
 929             break;
 930         case GDK_KEY_PRESS:
 931             gtk_menu_popup(GTK_MENU(menu), NULL, NULL, 0, NULL, 0, event->key.time);
 932             break;
 933         default:
 934             break;
 935     }
 936 }
 937
 938 /**
 939  * Show tool context specific modifier tip.
 940  */
 941 void
 942 sp_event_show_modifier_tip(Inkscape::MessageContext *message_context,
 943         GdkEvent *event, gchar const *ctrl_tip, gchar const *shift_tip,
 944         gchar const *alt_tip)
 945 {
 946     guint keyval = get_group0_keyval(&event->key);
 947
 948     bool ctrl = ctrl_tip && (MOD__CTRL
 949             || (keyval == GDK_Control_L)
 950             || (keyval == GDK_Control_R));
 951     bool shift = shift_tip
 952         && (MOD__SHIFT || (keyval == GDK_Shift_L) || (keyval == GDK_Shift_R));
 953     bool alt = alt_tip
 954         && (MOD__ALT
 955                 || (keyval == GDK_Alt_L)
 956                 || (keyval == GDK_Alt_R)
 957                 || (keyval == GDK_Meta_L)
 958                 || (keyval == GDK_Meta_R));
 959
 960     gchar *tip = g_strdup_printf("%s%s%s%s%s",
 961                                  ( ctrl ? ctrl_tip : "" ),
 962                                  ( ctrl && (shift || alt) ? "; " : "" ),
 963                                  ( shift ? shift_tip : "" ),
 964                                  ( (ctrl || shift) && alt ? "; " : "" ),
 965                                  ( alt ? alt_tip : "" ));
 966
 967     if (strlen(tip) > 0) {
 968         message_context->flash(Inkscape::INFORMATION_MESSAGE, tip);
 969     }
 970
 971     g_free(tip);
 972 }
 973
 974 /**
 975  * Return the keyval corresponding to the key event in group 0, i.e.,
 976  * in the main (English) layout.
 977  *
 978  * Use this instead of simply event->keyval, so that your keyboard shortcuts
 979  * work regardless of layouts (e.g., in Cyrillic).
 980  */
 981 guint
 982 get_group0_keyval(GdkEventKey *event)
 983 {
 984     guint keyval = 0;
 985     gdk_keymap_translate_keyboard_state(
 986             gdk_keymap_get_for_display(gdk_display_get_default()),
 987             event->hardware_keycode,
 988             (GdkModifierType) event->state,
 989             0   /*event->key.group*/,
 990             &keyval, NULL, NULL, NULL);
 991     return keyval;
 992 }
 993
 994 /**
 995  * Returns item at point p in desktop.
 996  *
 997  * If state includes alt key mask, cyclically selects under; honors
 998  * into_groups.
 999  */
1000 SPItem *
1001 sp_event_context_find_item (SPDesktop *desktop, NR::Point const p,
1002         bool select_under, bool into_groups)
1003 {
1004     SPItem *item;
1005
1006     if (select_under) {
1007         SPItem *selected_at_point =
1008             desktop->item_from_list_at_point_bottom (desktop->selection->itemList(), p);
1009         item = desktop->item_at_point(p, into_groups, selected_at_point);
1010         if (item == NULL) { // we may have reached bottom, flip over to the top
1011             item = desktop->item_at_point(p, into_groups, NULL);
1012         }
1013     } else
1014         item = desktop->item_at_point(p, into_groups, NULL);
1015
1016     return item;
1017 }
1018
1019 /**
1020  * Returns item if it is under point p in desktop, at any depth; otherwise returns NULL.
1021  *
1022  * Honors into_groups.
1023  */
1024 SPItem *
1025 sp_event_context_over_item (SPDesktop *desktop, SPItem *item, NR::Point const p)
1026 {
1027     GSList *temp = NULL;
1028     temp = g_slist_prepend (temp, item);
1029     SPItem *item_at_point = desktop->item_from_list_at_point_bottom (temp, p);
1030     g_slist_free (temp);
1031
1032     return item_at_point;
1033 }
1034
1035 /**
1036  * Called when SPEventContext subclass node attribute changed.
1037  */
1038 void
1039 ec_shape_event_attr_changed(Inkscape::XML::Node */*shape_repr*/, gchar const *name,
1040                             gchar const */*old_value*/, gchar const */*new_value*/,
1041                             bool const /*is_interactive*/, gpointer const data)
1042 {
1043     if (!name
1044             || !strcmp(name, "style")
1045             || SP_ATTRIBUTE_IS_CSS(sp_attribute_lookup(name))) {
1046         // no need to regenrate knotholder if only style changed
1047         return;
1048     }
1049
1050     SPEventContext *ec = SP_EVENT_CONTEXT(data);
1051
1052     if (ec->shape_knot_holder) {
1053         sp_knot_holder_destroy(ec->shape_knot_holder);
1054     }
1055     ec->shape_knot_holder = NULL;
1056
1057     SPDesktop *desktop = ec->desktop;
1058
1059     SPItem *item = sp_desktop_selection(desktop)->singleItem();
1060
1061     if (item) {
1062         ec->shape_knot_holder = sp_item_knot_holder(item, desktop);
1063     }
1064 }
1065
1066
1067 /*
1068   Local Variables:
1069   mode:c++
1070   c-file-style:"stroustrup"
1071   c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
1072   indent-tabs-mode:nil
1073   fill-column:99
1074   End:
1075 */
1076 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :