src/pencil-context.cpp

   1 /** \file
   2  * Pencil event context implementation.
   3  */
   4
   5 /*
   6  * Authors:
   7  *   Lauris Kaplinski <lauris@kaplinski.com>
   8  *   bulia byak <buliabyak@users.sf.net>
   9  *
  10  * Copyright (C) 2000 Lauris Kaplinski
  11  * Copyright (C) 2000-2001 Ximian, Inc.
  12  * Copyright (C) 2002 Lauris Kaplinski
  13  * Copyright (C) 2004 Monash University
  14  *
  15  * Released under GNU GPL, read the file 'COPYING' for more information
  16  */
  17
  18 #include <gdk/gdkkeysyms.h>
  19
  20 #include "pencil-context.h"
  21 #include "desktop.h"
  22 #include "desktop-handles.h"
  23 #include "selection.h"
  24 #include "selection-chemistry.h"
  25 #include "draw-anchor.h"
  26 #include "message-stack.h"
  27 #include "message-context.h"
  28 #include "modifier-fns.h"
  29 #include "sp-path.h"
  30 #include "preferences.h"
  31 #include "snap.h"
  32 #include "pixmaps/cursor-pencil.xpm"
  33 #include <2geom/sbasis-to-bezier.h>
  34 #include <2geom/bezier-utils.h>
  35 #include "display/canvas-bpath.h"
  36 #include <glibmm/i18n.h>
  37 #include "libnr/in-svg-plane.h"
  38 #include "context-fns.h"
  39 #include "sp-namedview.h"
  40 #include "xml/repr.h"
  41 #include "document.h"
  42 #include "desktop-style.h"
  43 #include "macros.h"
  44 #include "display/curve.h"
  45 #include "livarot/Path.h"
  46
  47 static void sp_pencil_context_class_init(SPPencilContextClass *klass);
  48 static void sp_pencil_context_init(SPPencilContext *pc);
  49 static void sp_pencil_context_setup(SPEventContext *ec);
  50 static void sp_pencil_context_dispose(GObject *object);
  51
  52 static gint sp_pencil_context_root_handler(SPEventContext *event_context, GdkEvent *event);
  53 static gint pencil_handle_button_press(SPPencilContext *const pc, GdkEventButton const &bevent);
  54 static gint pencil_handle_motion_notify(SPPencilContext *const pc, GdkEventMotion const &mevent);
  55 static gint pencil_handle_button_release(SPPencilContext *const pc, GdkEventButton const &revent);
  56 static gint pencil_handle_key_press(SPPencilContext *const pc, guint const keyval, guint const state);
  57 static gint pencil_handle_key_release(SPPencilContext *const pc, guint const keyval, guint const state);
  58
  59 static void spdc_set_startpoint(SPPencilContext *pc, Geom::Point const p);
  60 static void spdc_set_endpoint(SPPencilContext *pc, Geom::Point const p);
  61 static void spdc_finish_endpoint(SPPencilContext *pc);
  62 static void spdc_add_freehand_point(SPPencilContext *pc, Geom::Point p, guint state);
  63 static void fit_and_split(SPPencilContext *pc);
  64 static void interpolate(SPPencilContext *pc);
  65 static void sketch_interpolate(SPPencilContext *pc);
  66
  67 static SPDrawContextClass *pencil_parent_class;
  68 static Geom::Point pencil_drag_origin_w(0, 0);
  69 static bool pencil_within_tolerance = false;
  70
  71 /**
  72  * Register SPPencilContext class with Gdk and return its type number.
  73  */
  74 GType
  75 sp_pencil_context_get_type()
  76 {
  77     static GType type = 0;
  78     if (!type) {
  79         GTypeInfo info = {
  80             sizeof(SPPencilContextClass),
  81             NULL, NULL,
  82             (GClassInitFunc) sp_pencil_context_class_init,
  83             NULL, NULL,
  84             sizeof(SPPencilContext),
  85             4,
  86             (GInstanceInitFunc) sp_pencil_context_init,
  87             NULL,   /* value_table */
  88         };
  89         type = g_type_register_static(SP_TYPE_DRAW_CONTEXT, "SPPencilContext", &info, (GTypeFlags)0);
  90     }
  91     return type;
  92 }
  93
  94 /**
  95  * Initialize SPPencilContext vtable.
  96  */
  97 static void
  98 sp_pencil_context_class_init(SPPencilContextClass *klass)
  99 {
 100     GObjectClass *object_class;
 101     SPEventContextClass *event_context_class;
 102
 103     object_class = (GObjectClass *) klass;
 104     event_context_class = (SPEventContextClass *) klass;
 105
 106     pencil_parent_class = (SPDrawContextClass*)g_type_class_peek_parent(klass);
 107
 108     object_class->dispose = sp_pencil_context_dispose;
 109
 110     event_context_class->setup = sp_pencil_context_setup;
 111     event_context_class->root_handler = sp_pencil_context_root_handler;
 112 }
 113
 114 /**
 115  * Callback to initialize SPPencilContext object.
 116  */
 117 static void
 118 sp_pencil_context_init(SPPencilContext *pc)
 119 {
 120     SPEventContext *event_context = SP_EVENT_CONTEXT(pc);
 121
 122     event_context->cursor_shape = cursor_pencil_xpm;
 123     event_context->hot_x = 4;
 124     event_context->hot_y = 4;
 125
 126     pc->npoints = 0;
 127     pc->state = SP_PENCIL_CONTEXT_IDLE;
 128     pc->req_tangent = Geom::Point(0, 0);
 129
 130     // since SPPencilContext is not properly constructed...
 131     pc->sketch_interpolation = Geom::Piecewise<Geom::D2<Geom::SBasis> >();
 132     pc->sketch_n = 0;
 133 }
 134
 135 /**
 136  * Callback to setup SPPencilContext object.
 137  */
 138 static void
 139 sp_pencil_context_setup(SPEventContext *ec)
 140 {
 141     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 142     if (prefs->getBool("/tools/freehand/pencil/selcue")) {
 143         ec->enableSelectionCue();
 144     }
 145
 146     if (((SPEventContextClass *) pencil_parent_class)->setup) {
 147         ((SPEventContextClass *) pencil_parent_class)->setup(ec);
 148     }
 149
 150     SPPencilContext *const pc = SP_PENCIL_CONTEXT(ec);
 151     pc->is_drawing = false;
 152
 153     pc->anchor_statusbar = false;
 154 }
 155
 156 static void
 157 sp_pencil_context_dispose(GObject *object)
 158 {
 159     G_OBJECT_CLASS(pencil_parent_class)->dispose(object);
 160 }
 161
 162 /** Snaps new node relative to the previous node. */
 163 static void
 164 spdc_endpoint_snap(SPPencilContext const *pc, Geom::Point &p, guint const state)
 165 {
 166     if ((state & GDK_CONTROL_MASK)) { //CTRL enables constrained snapping
 167         spdc_endpoint_snap_rotation(pc, p, pc->p[0], state);
 168     } else {
 169         if (!(state & GDK_SHIFT_MASK)) { //SHIFT disables all snapping, except the angular snapping above
 170                                          //After all, the user explicitely asked for angular snapping by
 171                                          //pressing CTRL
 172             spdc_endpoint_snap_free(pc, p, state);
 173         }
 174     }
 175 }
 176
 177 /**
 178  * Callback for handling all pencil context events.
 179  */
 180 gint
 181 sp_pencil_context_root_handler(SPEventContext *const ec, GdkEvent *event)
 182 {
 183     SPPencilContext *const pc = SP_PENCIL_CONTEXT(ec);
 184
 185     gint ret = FALSE;
 186
 187     switch (event->type) {
 188         case GDK_BUTTON_PRESS:
 189             ret = pencil_handle_button_press(pc, event->button);
 190             break;
 191
 192         case GDK_MOTION_NOTIFY:
 193             ret = pencil_handle_motion_notify(pc, event->motion);
 194             break;
 195
 196         case GDK_BUTTON_RELEASE:
 197             ret = pencil_handle_button_release(pc, event->button);
 198             break;
 199
 200         case GDK_KEY_PRESS:
 201             ret = pencil_handle_key_press(pc, get_group0_keyval (&event->key), event->key.state);
 202             break;
 203
 204         case GDK_KEY_RELEASE:
 205             ret = pencil_handle_key_release(pc, get_group0_keyval (&event->key), event->key.state);
 206             break;
 207
 208         default:
 209             break;
 210     }
 211
 212     if (!ret) {
 213         gint (*const parent_root_handler)(SPEventContext *, GdkEvent *)
 214             = ((SPEventContextClass *) pencil_parent_class)->root_handler;
 215         if (parent_root_handler) {
 216             ret = parent_root_handler(ec, event);
 217         }
 218     }
 219
 220     return ret;
 221 }
 222
 223 static gint
 224 pencil_handle_button_press(SPPencilContext *const pc, GdkEventButton const &bevent)
 225 {
 226     gint ret = FALSE;
 227     SPEventContext *event_context = SP_EVENT_CONTEXT(pc);
 228     if ( bevent.button == 1  && !event_context->space_panning) {
 229
 230         SPDrawContext *dc = SP_DRAW_CONTEXT (pc);
 231         SPDesktop *desktop = SP_EVENT_CONTEXT_DESKTOP(dc);
 232         Inkscape::Selection *selection = sp_desktop_selection(desktop);
 233
 234         if (Inkscape::have_viable_layer(desktop, dc->_message_context) == false) {
 235             return TRUE;
 236         }
 237
 238         if (!pc->grab) {
 239             /* Grab mouse, so release will not pass unnoticed */
 240             pc->grab = SP_CANVAS_ITEM(desktop->acetate);
 241             sp_canvas_item_grab(pc->grab, ( GDK_KEY_PRESS_MASK | GDK_BUTTON_PRESS_MASK   |
 242                                             GDK_BUTTON_RELEASE_MASK |
 243                                             GDK_POINTER_MOTION_MASK  ),
 244                                 NULL, bevent.time);
 245         }
 246
 247         Geom::Point const button_w(bevent.x, bevent.y);
 248
 249         /* Find desktop coordinates */
 250         Geom::Point p = pc->desktop->w2d(button_w);
 251
 252         /* Test whether we hit any anchor. */
 253         SPDrawAnchor *anchor = spdc_test_inside(pc, button_w);
 254
 255         pencil_drag_origin_w = Geom::Point(bevent.x,bevent.y);
 256         pencil_within_tolerance = true;
 257
 258         switch (pc->state) {
 259             case SP_PENCIL_CONTEXT_ADDLINE:
 260                 /* Current segment will be finished with release */
 261                 ret = TRUE;
 262                 break;
 263             default:
 264                 /* Set first point of sequence */
 265                 SnapManager &m = desktop->namedview->snap_manager;
 266                 m.setup(desktop);
 267
 268                 if (bevent.state & GDK_CONTROL_MASK) {
 269                     if (!(bevent.state & GDK_SHIFT_MASK)) {
 270                         m.freeSnapReturnByRef(p, Inkscape::SNAPSOURCE_NODE_HANDLE);
 271                       }
 272                     spdc_create_single_dot(event_context, p, "/tools/freehand/pencil", bevent.state);
 273                     ret = true;
 274                     break;
 275                 }
 276                 if (anchor) {
 277                     p = anchor->dp;
 278                     desktop->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Continuing selected path"));
 279                 } else {
 280
 281                     if (!(bevent.state & GDK_SHIFT_MASK)) {
 282                         // This is the first click of a new curve; deselect item so that
 283                         // this curve is not combined with it (unless it is drawn from its
 284                         // anchor, which is handled by the sibling branch above)
 285                         selection->clear();
 286                         desktop->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Creating new path"));
 287                         m.freeSnapReturnByRef(p, Inkscape::SNAPSOURCE_NODE_HANDLE);
 288                     } else if (selection->singleItem() && SP_IS_PATH(selection->singleItem())) {
 289                         desktop->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Appending to selected path"));
 290                         m.freeSnapReturnByRef(p, Inkscape::SNAPSOURCE_NODE_HANDLE);
 291                     }
 292                 }
 293                 pc->sa = anchor;
 294                 spdc_set_startpoint(pc, p);
 295                 ret = TRUE;
 296                 break;
 297         }
 298
 299         pc->is_drawing = true;
 300     }
 301     return ret;
 302 }
 303
 304 static gint
 305 pencil_handle_motion_notify(SPPencilContext *const pc, GdkEventMotion const &mevent)
 306 {
 307     SPDesktop *const dt = pc->desktop;
 308
 309     if ((mevent.state & GDK_CONTROL_MASK) && (mevent.state & GDK_BUTTON1_MASK)) {
 310         // mouse was accidentally moved during Ctrl+click;
 311         // ignore the motion and create a single point
 312         pc->is_drawing = false;
 313         return TRUE;
 314     }
 315     gint ret = FALSE;
 316
 317     SPEventContext *event_context = SP_EVENT_CONTEXT(pc);
 318     if (event_context->space_panning || mevent.state & GDK_BUTTON2_MASK || mevent.state & GDK_BUTTON3_MASK) {
 319         // allow scrolling
 320         return FALSE;
 321     }
 322
 323     if ( ( mevent.state & GDK_BUTTON1_MASK ) && !pc->grab && pc->is_drawing) {
 324         /* Grab mouse, so release will not pass unnoticed */
 325         pc->grab = SP_CANVAS_ITEM(dt->acetate);
 326         sp_canvas_item_grab(pc->grab, ( GDK_KEY_PRESS_MASK | GDK_BUTTON_PRESS_MASK   |
 327                                         GDK_BUTTON_RELEASE_MASK |
 328                                         GDK_POINTER_MOTION_MASK  ),
 329                             NULL, mevent.time);
 330     }
 331
 332     /* Find desktop coordinates */
 333     Geom::Point p = dt->w2d(Geom::Point(mevent.x, mevent.y));
 334
 335     /* Test whether we hit any anchor. */
 336     SPDrawAnchor *anchor = spdc_test_inside(pc, Geom::Point(mevent.x, mevent.y));
 337
 338     if (pencil_within_tolerance) {
 339         Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 340         gint const tolerance = prefs->getIntLimited("/options/dragtolerance/value", 0, 0, 100);
 341         if ( Geom::LInfty( Geom::Point(mevent.x,mevent.y) - pencil_drag_origin_w ) < tolerance ) {
 342             return FALSE;   // Do not drag if we're within tolerance from origin.
 343         }
 344     }
 345
 346     // Once the user has moved farther than tolerance from the original location
 347     // (indicating they intend to move the object, not click), then always process the
 348     // motion notify coordinates as given (no snapping back to origin)
 349     pencil_within_tolerance = false;
 350
 351     switch (pc->state) {
 352         case SP_PENCIL_CONTEXT_ADDLINE:
 353             /* Set red endpoint */
 354             if (anchor) {
 355                 p = anchor->dp;
 356             } else {
 357                 Geom::Point ptnr(p);
 358                 spdc_endpoint_snap(pc, ptnr, mevent.state);
 359                 p = ptnr;
 360             }
 361             spdc_set_endpoint(pc, p);
 362             ret = TRUE;
 363             break;
 364         default:
 365             /* We may be idle or already freehand */
 366             if ( mevent.state & GDK_BUTTON1_MASK && pc->is_drawing ) {
 367                 if (pc->state == SP_PENCIL_CONTEXT_IDLE) {
 368                     sp_event_context_discard_delayed_snap_event(event_context);
 369                 }
 370                 pc->state = SP_PENCIL_CONTEXT_FREEHAND;
 371
 372                 if ( !pc->sa && !pc->green_anchor ) {
 373                     /* Create green anchor */
 374                     pc->green_anchor = sp_draw_anchor_new(pc, pc->green_curve, TRUE, pc->p[0]);
 375                 }
 376                 if (anchor) {
 377                     p = anchor->dp;
 378                 }
 379
 380                 if ( pc->npoints != 0) { // buttonpress may have happened before we entered draw context!
 381                     if (pc->ps.size() == 0) {
 382                         // Only in freehand mode we have to add the first point also to pc->ps (apparently)
 383                         // - We cannot add this point in spdc_set_startpoint, because we only need it for freehand
 384                         // - We cannot do this in the button press handler because at that point we don't know yet
 385                         //   wheter we're going into freehand mode or not
 386                         pc->ps.push_back(pc->p[0]);
 387                     }
 388                     spdc_add_freehand_point(pc, p, mevent.state);
 389                     ret = TRUE;
 390                 }
 391
 392                 if (anchor && !pc->anchor_statusbar) {
 393                     pc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("<b>Release</b> here to close and finish the path."));
 394                     pc->anchor_statusbar = true;
 395                 } else if (!anchor && pc->anchor_statusbar) {
 396                     pc->_message_context->clear();
 397                     pc->anchor_statusbar = false;
 398                 } else if (!anchor) {
 399                     pc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("Drawing a freehand path"));
 400                 }
 401
 402             } else {
 403                 if (anchor && !pc->anchor_statusbar) {
 404                     pc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("<b>Drag</b> to continue the path from this point."));
 405                     pc->anchor_statusbar = true;
 406                 } else if (!anchor && pc->anchor_statusbar) {
 407                     pc->_message_context->clear();
 408                     pc->anchor_statusbar = false;
 409                 }
 410             }
 411
 412             // Show the pre-snap indicator to communicate to the user where we would snap to if he/she were to
 413             // a) press the mousebutton to start a freehand drawing, or
 414             // b) release the mousebutton to finish a freehand drawing
 415             if (!sp_event_context_knot_mouseover(pc)) {
 416                 SnapManager &m = dt->namedview->snap_manager;
 417                 m.setup(dt);
 418                 m.preSnap(Inkscape::SnapCandidatePoint(p, Inkscape::SNAPSOURCE_NODE_HANDLE));
 419             }
 420             break;
 421     }
 422     return ret;
 423 }
 424
 425 static gint
 426 pencil_handle_button_release(SPPencilContext *const pc, GdkEventButton const &revent)
 427 {
 428     gint ret = FALSE;
 429
 430     SPEventContext *event_context = SP_EVENT_CONTEXT(pc);
 431     if ( revent.button == 1 && pc->is_drawing && !event_context->space_panning) {
 432         SPDesktop *const dt = pc->desktop;
 433
 434         pc->is_drawing = false;
 435
 436         /* Find desktop coordinates */
 437         Geom::Point p = dt->w2d(Geom::Point(revent.x, revent.y));
 438
 439         /* Test whether we hit any anchor. */
 440         SPDrawAnchor *anchor = spdc_test_inside(pc, Geom::Point(revent.x,
 441                                                               revent.y));
 442
 443         switch (pc->state) {
 444             case SP_PENCIL_CONTEXT_IDLE:
 445                 /* Releasing button in idle mode means single click */
 446                 /* We have already set up start point/anchor in button_press */
 447                 if (!(revent.state & GDK_CONTROL_MASK)) {
 448                     // Ctrl+click creates a single point so only set context in ADDLINE mode when Ctrl isn't pressed
 449                     pc->state = SP_PENCIL_CONTEXT_ADDLINE;
 450                 }
 451                 ret = TRUE;
 452                 break;
 453             case SP_PENCIL_CONTEXT_ADDLINE:
 454                 /* Finish segment now */
 455                 if (anchor) {
 456                     p = anchor->dp;
 457                 } else {
 458                     spdc_endpoint_snap(pc, p, revent.state);
 459                 }
 460                 pc->ea = anchor;
 461                 spdc_set_endpoint(pc, p);
 462                 spdc_finish_endpoint(pc);
 463                 pc->state = SP_PENCIL_CONTEXT_IDLE;
 464                 sp_event_context_discard_delayed_snap_event(event_context);
 465                 ret = TRUE;
 466                 break;
 467             case SP_PENCIL_CONTEXT_FREEHAND:
 468                 if (revent.state & GDK_MOD1_MASK) {
 469                     /* sketch mode: interpolate the sketched path and improve the current output path with the new interpolation. don't finish sketch */
 470
 471                     sketch_interpolate(pc);
 472
 473                     if (pc->green_anchor) {
 474                         pc->green_anchor = sp_draw_anchor_destroy(pc->green_anchor);
 475                     }
 476
 477                     pc->state = SP_PENCIL_CONTEXT_SKETCH;
 478                 } else {
 479                     /* Finish segment now */
 480                     /// \todo fixme: Clean up what follows (Lauris)
 481                     if (anchor) {
 482                         p = anchor->dp;
 483                     } else {
 484                         Geom::Point p_end = p;
 485                         spdc_endpoint_snap(pc, p_end, revent.state);
 486                         if (p_end != p) {
 487                             // then we must have snapped!
 488                             spdc_add_freehand_point(pc, p_end, revent.state);
 489                         }
 490                     }
 491
 492                     pc->ea = anchor;
 493                     /* Write curves to object */
 494
 495                     dt->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Finishing freehand"));
 496
 497                     interpolate(pc);
 498                     spdc_concat_colors_and_flush(pc, FALSE);
 499                     pc->sa = NULL;
 500                     pc->ea = NULL;
 501                     if (pc->green_anchor) {
 502                         pc->green_anchor = sp_draw_anchor_destroy(pc->green_anchor);
 503                     }
 504                     pc->state = SP_PENCIL_CONTEXT_IDLE;
 505                     // reset sketch mode too
 506                     pc->sketch_n = 0;
 507                 }
 508                 ret = TRUE;
 509                 break;
 510             case SP_PENCIL_CONTEXT_SKETCH:
 511             default:
 512                 break;
 513         }
 514
 515         if (pc->grab) {
 516             /* Release grab now */
 517             sp_canvas_item_ungrab(pc->grab, revent.time);
 518             pc->grab = NULL;
 519         }
 520
 521         ret = TRUE;
 522     }
 523     return ret;
 524 }
 525
 526 static void
 527 pencil_cancel (SPPencilContext *const pc)
 528 {
 529     if (pc->grab) {
 530         /* Release grab now */
 531         sp_canvas_item_ungrab(pc->grab, 0);
 532         pc->grab = NULL;
 533     }
 534
 535     pc->is_drawing = false;
 536     pc->state = SP_PENCIL_CONTEXT_IDLE;
 537     sp_event_context_discard_delayed_snap_event(SP_EVENT_CONTEXT(pc));
 538
 539     pc->red_curve->reset();
 540     sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), NULL);
 541     while (pc->green_bpaths) {
 542         gtk_object_destroy(GTK_OBJECT(pc->green_bpaths->data));
 543         pc->green_bpaths = g_slist_remove(pc->green_bpaths, pc->green_bpaths->data);
 544     }
 545     pc->green_curve->reset();
 546     if (pc->green_anchor) {
 547         pc->green_anchor = sp_draw_anchor_destroy(pc->green_anchor);
 548     }
 549
 550     pc->_message_context->clear();
 551     pc->_message_context->flash(Inkscape::NORMAL_MESSAGE, _("Drawing cancelled"));
 552
 553     sp_canvas_end_forced_full_redraws(pc->desktop->canvas);
 554 }
 555
 556 static gint
 557 pencil_handle_key_press(SPPencilContext *const pc, guint const keyval, guint const state)
 558 {
 559     gint ret = FALSE;
 560     switch (keyval) {
 561         case GDK_Up:
 562         case GDK_Down:
 563         case GDK_KP_Up:
 564         case GDK_KP_Down:
 565             // Prevent the zoom field from activation.
 566             if (!mod_ctrl_only(state)) {
 567                 ret = TRUE;
 568             }
 569             break;
 570         case GDK_Escape:
 571             if (pc->npoints != 0) {
 572                 // if drawing, cancel, otherwise pass it up for deselecting
 573                 if (pc->state != SP_PENCIL_CONTEXT_IDLE) {
 574                     pencil_cancel (pc);
 575                     ret = TRUE;
 576                 }
 577             }
 578             break;
 579         case GDK_z:
 580         case GDK_Z:
 581             if (mod_ctrl_only(state) && pc->npoints != 0) {
 582                 // if drawing, cancel, otherwise pass it up for undo
 583                 if (pc->state != SP_PENCIL_CONTEXT_IDLE) {
 584                     pencil_cancel (pc);
 585                     ret = TRUE;
 586                 }
 587             }
 588             break;
 589         case GDK_g:
 590         case GDK_G:
 591             if (mod_shift_only(state)) {
 592                 sp_selection_to_guides(SP_EVENT_CONTEXT(pc)->desktop);
 593                 ret = true;
 594             }
 595             break;
 596         case GDK_Alt_L:
 597         case GDK_Alt_R:
 598         case GDK_Meta_L:
 599         case GDK_Meta_R:
 600             if (pc->state == SP_PENCIL_CONTEXT_IDLE) {
 601                 pc->desktop->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("<b>Sketch mode</b>: holding <b>Alt</b> interpolates between sketched paths. Release <b>Alt</b> to finalize."));
 602             }
 603             break;
 604         default:
 605             break;
 606     }
 607     return ret;
 608 }
 609
 610 static gint
 611 pencil_handle_key_release(SPPencilContext *const pc, guint const keyval, guint const /*state*/)
 612 {
 613     gint ret = FALSE;
 614     switch (keyval) {
 615         case GDK_Alt_L:
 616         case GDK_Alt_R:
 617         case GDK_Meta_L:
 618         case GDK_Meta_R:
 619             if (pc->state == SP_PENCIL_CONTEXT_SKETCH) {
 620                 spdc_concat_colors_and_flush(pc, FALSE);
 621                 pc->sketch_n = 0;
 622                 pc->sa = NULL;
 623                 pc->ea = NULL;
 624                 if (pc->green_anchor) {
 625                     pc->green_anchor = sp_draw_anchor_destroy(pc->green_anchor);
 626                 }
 627                 pc->state = SP_PENCIL_CONTEXT_IDLE;
 628                 sp_event_context_discard_delayed_snap_event(SP_EVENT_CONTEXT(pc));
 629                 pc->desktop->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Finishing freehand sketch"));
 630                 ret = TRUE;
 631             }
 632             break;
 633         default:
 634             break;
 635     }
 636     return ret;
 637 }
 638
 639 /**
 640  * Reset points and set new starting point.
 641  */
 642 static void
 643 spdc_set_startpoint(SPPencilContext *const pc, Geom::Point const p)
 644 {
 645     pc->npoints = 0;
 646     pc->red_curve_is_valid = false;
 647     if (in_svg_plane(p)) {
 648         pc->p[pc->npoints++] = p;
 649     }
 650 }
 651
 652 /**
 653  * Change moving endpoint position.
 654  * <ul>
 655  * <li>Ctrl constrains to moving to H/V direction, snapping in given direction.
 656  * <li>Otherwise we snap freely to whatever attractors are available.
 657  * </ul>
 658  *
 659  * Number of points is (re)set to 2 always, 2nd point is modified.
 660  * We change RED curve.
 661  */
 662 static void
 663 spdc_set_endpoint(SPPencilContext *const pc, Geom::Point const p)
 664 {
 665     if (pc->npoints == 0) {
 666         return;
 667         /* May occur if first point wasn't in SVG plane (e.g. weird w2d transform, perhaps from bad
 668          * zoom setting).
 669          */
 670     }
 671     g_return_if_fail( pc->npoints > 0 );
 672
 673     pc->red_curve->reset();
 674     if ( ( p == pc->p[0] )
 675          || !in_svg_plane(p) )
 676     {
 677         pc->npoints = 1;
 678     } else {
 679         pc->p[1] = p;
 680         pc->npoints = 2;
 681
 682         pc->red_curve->moveto(pc->p[0]);
 683         pc->red_curve->lineto(pc->p[1]);
 684         pc->red_curve_is_valid = true;
 685
 686         sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), pc->red_curve);
 687     }
 688 }
 689
 690 /**
 691  * Finalize addline.
 692  *
 693  * \todo
 694  * fixme: I'd like remove red reset from concat colors (lauris).
 695  * Still not sure, how it will make most sense.
 696  */
 697 static void
 698 spdc_finish_endpoint(SPPencilContext *const pc)
 699 {
 700     if ( ( pc->red_curve->is_empty() )
 701          || ( *(pc->red_curve->first_point()) == *(pc->red_curve->second_point())   ) )
 702     {
 703         pc->red_curve->reset();
 704         sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), NULL);
 705     } else {
 706         /* Write curves to object. */
 707         spdc_concat_colors_and_flush(pc, FALSE);
 708         pc->sa = NULL;
 709         pc->ea = NULL;
 710     }
 711 }
 712
 713
 714 static void
 715 spdc_add_freehand_point(SPPencilContext *pc, Geom::Point p, guint /*state*/)
 716 {
 717     g_assert( pc->npoints > 0 );
 718     g_return_if_fail(unsigned(pc->npoints) < G_N_ELEMENTS(pc->p));
 719
 720     if ( ( p != pc->p[ pc->npoints - 1 ] )
 721          && in_svg_plane(p) )
 722     {
 723         pc->ps.push_back(p);
 724         pc->p[pc->npoints++] = p;
 725         fit_and_split(pc);
 726     }
 727 }
 728
 729 static inline double
 730 square(double const x)
 731 {
 732     return x * x;
 733 }
 734
 735 static void
 736 interpolate(SPPencilContext *pc)
 737 {
 738     if ( pc->ps.size() <= 1 ) {
 739         return;
 740     }
 741
 742     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 743     double const tol = prefs->getDoubleLimited("/tools/freehand/pencil/tolerance", 10.0, 1.0, 100.0) * 0.4;
 744     double const tolerance_sq = 0.02 * square( pc->desktop->w2d().descrim() *
 745                                                tol) * exp(0.2*tol - 2);
 746
 747     g_assert(is_zero(pc->req_tangent)
 748              || is_unit_vector(pc->req_tangent));
 749     Geom::Point const tHatEnd(0, 0);
 750
 751     guint n_points  = pc->ps.size();
 752     pc->green_curve->reset();
 753     pc->red_curve->reset();
 754     pc->red_curve_is_valid = false;
 755
 756     Geom::Point * b = g_new(Geom::Point, 4*n_points);
 757     Geom::Point * points = g_new(Geom::Point, 4*n_points);
 758     for (unsigned int i = 0; i < pc->ps.size(); i++) {
 759         points[i] = pc->ps[i];
 760     }
 761
 762     // worst case gives us a segment per point
 763     int max_segs = 4*n_points;
 764
 765     int const n_segs = Geom::bezier_fit_cubic_r(b, points, n_points,
 766                                              tolerance_sq, max_segs);
 767
 768     if ( n_segs > 0)
 769     {
 770         /* Fit and draw and reset state */
 771         pc->green_curve->moveto(b[0]);
 772         for (int c = 0; c < n_segs; c++) {
 773             pc->green_curve->curveto(b[4*c+1], b[4*c+2], b[4*c+3]);
 774         }
 775         sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), pc->green_curve);
 776
 777         /* Fit and draw and copy last point */
 778         g_assert(!pc->green_curve->is_empty());
 779
 780         /* Set up direction of next curve. */
 781         {
 782             Geom::CubicBezier const * last_seg = dynamic_cast<Geom::CubicBezier const *>(pc->green_curve->last_segment());
 783             g_assert( last_seg );      // Relevance: validity of (*last_seg)[2]
 784             pc->p[0] = last_seg->finalPoint();
 785             pc->npoints = 1;
 786             Geom::Point const req_vec( pc->p[0] - (*last_seg)[2] );
 787             pc->req_tangent = ( ( Geom::is_zero(req_vec) || !in_svg_plane(req_vec) )
 788                                 ? Geom::Point(0, 0)
 789                                 : Geom::unit_vector(req_vec) );
 790         }
 791     }
 792     g_free(b);
 793     g_free(points);
 794     pc->ps.clear();
 795 }
 796
 797
 798 /* interpolates the sketched curve and tweaks the current sketch interpolation*/
 799 static void
 800 sketch_interpolate(SPPencilContext *pc)
 801 {
 802     if ( pc->ps.size() <= 1 ) {
 803         return;
 804     }
 805
 806     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 807     double const tol = prefs->getDoubleLimited("/tools/freehand/pencil/tolerance", 10.0, 1.0, 100.0) * 0.4;
 808     double const tolerance_sq = 0.02 * square( pc->desktop->w2d().descrim() *
 809                                                tol) * exp(0.2*tol - 2);
 810
 811     bool average_all_sketches = prefs->getBool("/tools/freehand/pencil/average_all_sketches", true);
 812
 813     g_assert(is_zero(pc->req_tangent)
 814              || is_unit_vector(pc->req_tangent));
 815     Geom::Point const tHatEnd(0, 0);
 816
 817     guint n_points  = pc->ps.size();
 818     pc->red_curve->reset();
 819     pc->red_curve_is_valid = false;
 820
 821     Geom::Point * b = g_new(Geom::Point, 4*n_points);
 822     Geom::Point * points = g_new(Geom::Point, 4*n_points);
 823     for (unsigned i = 0; i < pc->ps.size(); i++) {
 824         points[i] = pc->ps[i];
 825     }
 826
 827     // worst case gives us a segment per point
 828     int max_segs = 4*n_points;
 829
 830     int const n_segs = Geom::bezier_fit_cubic_r(b, points, n_points,
 831                                              tolerance_sq, max_segs);
 832
 833     if ( n_segs > 0)
 834     {
 835         Geom::Path fit(b[0]);
 836         for (int c = 0; c < n_segs; c++) {
 837             fit.appendNew<Geom::CubicBezier>(b[4*c+1], b[4*c+2], b[4*c+3]);
 838         }
 839         Geom::Piecewise<Geom::D2<Geom::SBasis> > fit_pwd2 = fit.toPwSb();
 840
 841         double t =0.;
 842         if ( pc->sketch_n > 0 ) {
 843             if (average_all_sketches) {
 844                 // Average = (sum of all) / n
 845                 //         = (sum of all + new one) / n+1
 846                 //         = ((old average)*n + new one) / n+1
 847                 t = pc->sketch_n / (pc->sketch_n + 1.);
 848             } else {
 849                 t = 0.5;
 850             }
 851             pc->sketch_interpolation = Geom::lerp(t, fit_pwd2, pc->sketch_interpolation);
 852             // simplify path, to eliminate small segments
 853             Path *path = new Path;
 854             path->LoadPathVector(Geom::path_from_piecewise(pc->sketch_interpolation, 0.01));
 855             path->Simplify(0.5);
 856             Geom::PathVector *pathv = path->MakePathVector();
 857             pc->sketch_interpolation = (*pathv)[0].toPwSb();
 858             delete path;
 859             delete pathv;
 860         } else {
 861             pc->sketch_interpolation = fit_pwd2;
 862         }
 863         pc->sketch_n++;
 864
 865         pc->green_curve->reset();
 866         pc->green_curve->set_pathvector(Geom::path_from_piecewise(pc->sketch_interpolation, 0.01));
 867         sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), pc->green_curve);
 868
 869         /* Fit and draw and copy last point */
 870         g_assert(!pc->green_curve->is_empty());
 871
 872         /* Set up direction of next curve. */
 873         {
 874             Geom::CubicBezier const * last_seg = dynamic_cast<Geom::CubicBezier const *>(pc->green_curve->last_segment());
 875             g_assert( last_seg );      // Relevance: validity of (*last_seg)[2]
 876             pc->p[0] = last_seg->finalPoint();
 877             pc->npoints = 1;
 878             Geom::Point const req_vec( pc->p[0] - (*last_seg)[2] );
 879             pc->req_tangent = ( ( Geom::is_zero(req_vec) || !in_svg_plane(req_vec) )
 880                                 ? Geom::Point(0, 0)
 881                                 : Geom::unit_vector(req_vec) );
 882         }
 883     }
 884     g_free(b);
 885     g_free(points);
 886     pc->ps.clear();
 887 }
 888
 889 static void
 890 fit_and_split(SPPencilContext *pc)
 891 {
 892     g_assert( pc->npoints > 1 );
 893
 894     double const tolerance_sq = 0;
 895
 896     Geom::Point b[4];
 897     g_assert(is_zero(pc->req_tangent)
 898              || is_unit_vector(pc->req_tangent));
 899     Geom::Point const tHatEnd(0, 0);
 900     int const n_segs = Geom::bezier_fit_cubic_full(b, NULL, pc->p, pc->npoints,
 901                                                 pc->req_tangent, tHatEnd,
 902                                                 tolerance_sq, 1);
 903     if ( n_segs > 0
 904          && unsigned(pc->npoints) < G_N_ELEMENTS(pc->p) )
 905     {
 906         /* Fit and draw and reset state */
 907         pc->red_curve->reset();
 908         pc->red_curve->moveto(b[0]);
 909         pc->red_curve->curveto(b[1], b[2], b[3]);
 910         sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), pc->red_curve);
 911         pc->red_curve_is_valid = true;
 912     } else {
 913         /* Fit and draw and copy last point */
 914
 915         g_assert(!pc->red_curve->is_empty());
 916
 917         /* Set up direction of next curve. */
 918         {
 919             Geom::CubicBezier const * last_seg = dynamic_cast<Geom::CubicBezier const *>(pc->red_curve->last_segment());
 920             g_assert( last_seg );      // Relevance: validity of (*last_seg)[2]
 921             pc->p[0] = last_seg->finalPoint();
 922             pc->npoints = 1;
 923             Geom::Point const req_vec( pc->p[0] - (*last_seg)[2] );
 924             pc->req_tangent = ( ( Geom::is_zero(req_vec) || !in_svg_plane(req_vec) )
 925                                 ? Geom::Point(0, 0)
 926                                 : Geom::unit_vector(req_vec) );
 927         }
 928
 929         pc->green_curve->append_continuous(pc->red_curve, 0.0625);
 930         SPCurve *curve = pc->red_curve->copy();
 931
 932         /// \todo fixme:
 933         SPCanvasItem *cshape = sp_canvas_bpath_new(sp_desktop_sketch(pc->desktop), curve);
 934         curve->unref();
 935         sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(cshape), pc->green_color, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 936
 937         pc->green_bpaths = g_slist_prepend(pc->green_bpaths, cshape);
 938
 939         pc->red_curve_is_valid = false;
 940     }
 941 }
 942
 943
 944 /*
 945   Local Variables:
 946   mode:c++
 947   c-file-style:"stroustrup"
 948   c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
 949   indent-tabs-mode:nil
 950   fill-column:99
 951   End:
 952 */
 953 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :