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         Geom::Point const button_w(bevent.x, bevent.y);
 239
 240         /* Find desktop coordinates */
 241         Geom::Point p = pc->desktop->w2d(button_w);
 242
 243         /* Test whether we hit any anchor. */
 244         SPDrawAnchor *anchor = spdc_test_inside(pc, button_w);
 245
 246         pencil_drag_origin_w = Geom::Point(bevent.x,bevent.y);
 247         pencil_within_tolerance = true;
 248
 249         switch (pc->state) {
 250             case SP_PENCIL_CONTEXT_ADDLINE:
 251                 /* Current segment will be finished with release */
 252                 ret = TRUE;
 253                 break;
 254             default:
 255                 /* Set first point of sequence */
 256                 SnapManager &m = desktop->namedview->snap_manager;
 257                 m.setup(desktop);
 258
 259                 if (bevent.state & GDK_CONTROL_MASK) {
 260                     if (!(bevent.state & GDK_SHIFT_MASK)) {
 261                         m.freeSnapReturnByRef(p, Inkscape::SNAPSOURCE_NODE_HANDLE);
 262                       }
 263                     spdc_create_single_dot(event_context, p, "/tools/freehand/pencil", bevent.state);
 264                     ret = true;
 265                     break;
 266                 }
 267                 if (anchor) {
 268                     p = anchor->dp;
 269                     desktop->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Continuing selected path"));
 270                 } else {
 271
 272                     if (!(bevent.state & GDK_SHIFT_MASK)) {
 273                         // This is the first click of a new curve; deselect item so that
 274                         // this curve is not combined with it (unless it is drawn from its
 275                         // anchor, which is handled by the sibling branch above)
 276                         selection->clear();
 277                         desktop->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Creating new path"));
 278                         m.freeSnapReturnByRef(p, Inkscape::SNAPSOURCE_NODE_HANDLE);
 279                     } else if (selection->singleItem() && SP_IS_PATH(selection->singleItem())) {
 280                         desktop->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Appending to selected path"));
 281                         m.freeSnapReturnByRef(p, Inkscape::SNAPSOURCE_NODE_HANDLE);
 282                     }
 283                 }
 284                 pc->sa = anchor;
 285                 spdc_set_startpoint(pc, p);
 286                 ret = TRUE;
 287                 break;
 288         }
 289
 290         pc->is_drawing = true;
 291     }
 292     return ret;
 293 }
 294
 295 static gint
 296 pencil_handle_motion_notify(SPPencilContext *const pc, GdkEventMotion const &mevent)
 297 {
 298     SPDesktop *const dt = pc->desktop;
 299
 300     if ((mevent.state & GDK_CONTROL_MASK) && (mevent.state & GDK_BUTTON1_MASK)) {
 301         // mouse was accidentally moved during Ctrl+click;
 302         // ignore the motion and create a single point
 303         pc->is_drawing = false;
 304         return TRUE;
 305     }
 306     gint ret = FALSE;
 307
 308     SPEventContext *event_context = SP_EVENT_CONTEXT(pc);
 309     if (event_context->space_panning || mevent.state & GDK_BUTTON2_MASK || mevent.state & GDK_BUTTON3_MASK) {
 310         // allow scrolling
 311         return FALSE;
 312     }
 313
 314     if ( ( mevent.state & GDK_BUTTON1_MASK ) && !pc->grab && pc->is_drawing) {
 315         /* Grab mouse, so release will not pass unnoticed */
 316         pc->grab = SP_CANVAS_ITEM(dt->acetate);
 317         sp_canvas_item_grab(pc->grab, ( GDK_KEY_PRESS_MASK | GDK_BUTTON_PRESS_MASK   |
 318                                         GDK_BUTTON_RELEASE_MASK |
 319                                         GDK_POINTER_MOTION_MASK  ),
 320                             NULL, mevent.time);
 321     }
 322
 323     /* Find desktop coordinates */
 324     Geom::Point p = dt->w2d(Geom::Point(mevent.x, mevent.y));
 325
 326     /* Test whether we hit any anchor. */
 327     SPDrawAnchor *anchor = spdc_test_inside(pc, Geom::Point(mevent.x, mevent.y));
 328
 329     if (pencil_within_tolerance) {
 330         Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 331         gint const tolerance = prefs->getIntLimited("/options/dragtolerance/value", 0, 0, 100);
 332         if ( Geom::LInfty( Geom::Point(mevent.x,mevent.y) - pencil_drag_origin_w ) < tolerance ) {
 333             return FALSE;   // Do not drag if we're within tolerance from origin.
 334         }
 335     }
 336
 337     // Once the user has moved farther than tolerance from the original location
 338     // (indicating they intend to move the object, not click), then always process the
 339     // motion notify coordinates as given (no snapping back to origin)
 340     pencil_within_tolerance = false;
 341
 342     switch (pc->state) {
 343         case SP_PENCIL_CONTEXT_ADDLINE:
 344             /* Set red endpoint */
 345             if (anchor) {
 346                 p = anchor->dp;
 347             } else {
 348                 Geom::Point ptnr(p);
 349                 spdc_endpoint_snap(pc, ptnr, mevent.state);
 350                 p = ptnr;
 351             }
 352             spdc_set_endpoint(pc, p);
 353             ret = TRUE;
 354             break;
 355         default:
 356             /* We may be idle or already freehand */
 357             if ( mevent.state & GDK_BUTTON1_MASK && pc->is_drawing ) {
 358                 if (pc->state == SP_PENCIL_CONTEXT_IDLE) {
 359                     sp_event_context_discard_delayed_snap_event(event_context);
 360                 }
 361                 pc->state = SP_PENCIL_CONTEXT_FREEHAND;
 362
 363                 if ( !pc->sa && !pc->green_anchor ) {
 364                     /* Create green anchor */
 365                     pc->green_anchor = sp_draw_anchor_new(pc, pc->green_curve, TRUE, pc->p[0]);
 366                 }
 367                 /** \todo
 368                  * fixme: I am not sure whether we want to snap to anchors
 369                  * in middle of freehand (Lauris)
 370                  */
 371                 if (anchor) {
 372                     p = anchor->dp;
 373                 }
 374
 375                 if ( pc->npoints != 0) { // buttonpress may have happened before we entered draw context!
 376                     spdc_add_freehand_point(pc, p, mevent.state);
 377                     ret = TRUE;
 378                 }
 379
 380                 if (anchor && !pc->anchor_statusbar) {
 381                     pc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("<b>Release</b> here to close and finish the path."));
 382                     pc->anchor_statusbar = true;
 383                 } else if (!anchor && pc->anchor_statusbar) {
 384                     pc->_message_context->clear();
 385                     pc->anchor_statusbar = false;
 386                 } else if (!anchor) {
 387                     pc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("Drawing a freehand path"));
 388                 }
 389
 390             } else {
 391                 if (anchor && !pc->anchor_statusbar) {
 392                     pc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("<b>Drag</b> to continue the path from this point."));
 393                     pc->anchor_statusbar = true;
 394                 } else if (!anchor && pc->anchor_statusbar) {
 395                     pc->_message_context->clear();
 396                     pc->anchor_statusbar = false;
 397                 }
 398                 if (sp_event_context_knot_mouseover(pc)) {
 399                     SnapManager &m = dt->namedview->snap_manager;
 400                     m.setup(dt);
 401                     m.preSnap(Inkscape::SnapCandidatePoint(p, Inkscape::SNAPSOURCE_NODE_HANDLE));
 402                 }
 403             }
 404             break;
 405     }
 406     return ret;
 407 }
 408
 409 static gint
 410 pencil_handle_button_release(SPPencilContext *const pc, GdkEventButton const &revent)
 411 {
 412     gint ret = FALSE;
 413
 414     SPEventContext *event_context = SP_EVENT_CONTEXT(pc);
 415     if ( revent.button == 1 && pc->is_drawing && !event_context->space_panning) {
 416         SPDesktop *const dt = pc->desktop;
 417
 418         pc->is_drawing = false;
 419
 420         /* Find desktop coordinates */
 421         Geom::Point p = dt->w2d(Geom::Point(revent.x, revent.y));
 422
 423         /* Test whether we hit any anchor. */
 424         SPDrawAnchor *anchor = spdc_test_inside(pc, Geom::Point(revent.x,
 425                                                               revent.y));
 426
 427         switch (pc->state) {
 428             case SP_PENCIL_CONTEXT_IDLE:
 429                 /* Releasing button in idle mode means single click */
 430                 /* We have already set up start point/anchor in button_press */
 431                 if (!(revent.state & GDK_CONTROL_MASK)) {
 432                     // Ctrl+click creates a single point so only set context in ADDLINE mode when Ctrl isn't pressed
 433                     pc->state = SP_PENCIL_CONTEXT_ADDLINE;
 434                 }
 435                 ret = TRUE;
 436                 break;
 437             case SP_PENCIL_CONTEXT_ADDLINE:
 438                 /* Finish segment now */
 439                 if (anchor) {
 440                     p = anchor->dp;
 441                 } else {
 442                     spdc_endpoint_snap(pc, p, revent.state);
 443                 }
 444                 pc->ea = anchor;
 445                 spdc_set_endpoint(pc, p);
 446                 spdc_finish_endpoint(pc);
 447                 pc->state = SP_PENCIL_CONTEXT_IDLE;
 448                 sp_event_context_discard_delayed_snap_event(event_context);
 449                 ret = TRUE;
 450                 break;
 451             case SP_PENCIL_CONTEXT_FREEHAND:
 452                 if (revent.state & GDK_MOD1_MASK) {
 453                     /* sketch mode: interpolate the sketched path and improve the current output path with the new interpolation. don't finish sketch */
 454
 455                     sketch_interpolate(pc);
 456
 457                     if (pc->green_anchor) {
 458                         pc->green_anchor = sp_draw_anchor_destroy(pc->green_anchor);
 459                     }
 460
 461                     pc->state = SP_PENCIL_CONTEXT_SKETCH;
 462                 } else {
 463                     /* Finish segment now */
 464                     /// \todo fixme: Clean up what follows (Lauris)
 465                     if (anchor) {
 466                         p = anchor->dp;
 467                     }
 468                     pc->ea = anchor;
 469                     /* Write curves to object */
 470
 471                     dt->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Finishing freehand"));
 472
 473                     interpolate(pc);
 474                     spdc_concat_colors_and_flush(pc, FALSE);
 475                     pc->sa = NULL;
 476                     pc->ea = NULL;
 477                     if (pc->green_anchor) {
 478                         pc->green_anchor = sp_draw_anchor_destroy(pc->green_anchor);
 479                     }
 480                     pc->state = SP_PENCIL_CONTEXT_IDLE;
 481                     // reset sketch mode too
 482                     pc->sketch_n = 0;
 483                 }
 484                 ret = TRUE;
 485                 break;
 486             case SP_PENCIL_CONTEXT_SKETCH:
 487             default:
 488                 break;
 489         }
 490
 491         if (pc->grab) {
 492             /* Release grab now */
 493             sp_canvas_item_ungrab(pc->grab, revent.time);
 494             pc->grab = NULL;
 495         }
 496
 497         ret = TRUE;
 498     }
 499     return ret;
 500 }
 501
 502 static void
 503 pencil_cancel (SPPencilContext *const pc)
 504 {
 505     if (pc->grab) {
 506         /* Release grab now */
 507         sp_canvas_item_ungrab(pc->grab, 0);
 508         pc->grab = NULL;
 509     }
 510
 511     pc->is_drawing = false;
 512     pc->state = SP_PENCIL_CONTEXT_IDLE;
 513     sp_event_context_discard_delayed_snap_event(SP_EVENT_CONTEXT(pc));
 514
 515     pc->red_curve->reset();
 516     sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), NULL);
 517     while (pc->green_bpaths) {
 518         gtk_object_destroy(GTK_OBJECT(pc->green_bpaths->data));
 519         pc->green_bpaths = g_slist_remove(pc->green_bpaths, pc->green_bpaths->data);
 520     }
 521     pc->green_curve->reset();
 522     if (pc->green_anchor) {
 523         pc->green_anchor = sp_draw_anchor_destroy(pc->green_anchor);
 524     }
 525
 526     pc->_message_context->clear();
 527     pc->_message_context->flash(Inkscape::NORMAL_MESSAGE, _("Drawing cancelled"));
 528
 529     sp_canvas_end_forced_full_redraws(pc->desktop->canvas);
 530 }
 531
 532 static gint
 533 pencil_handle_key_press(SPPencilContext *const pc, guint const keyval, guint const state)
 534 {
 535     gint ret = FALSE;
 536     switch (keyval) {
 537         case GDK_Up:
 538         case GDK_Down:
 539         case GDK_KP_Up:
 540         case GDK_KP_Down:
 541             // Prevent the zoom field from activation.
 542             if (!mod_ctrl_only(state)) {
 543                 ret = TRUE;
 544             }
 545             break;
 546         case GDK_Escape:
 547             if (pc->npoints != 0) {
 548                 // if drawing, cancel, otherwise pass it up for deselecting
 549                 if (pc->state != SP_PENCIL_CONTEXT_IDLE) {
 550                     pencil_cancel (pc);
 551                     ret = TRUE;
 552                 }
 553             }
 554             break;
 555         case GDK_z:
 556         case GDK_Z:
 557             if (mod_ctrl_only(state) && pc->npoints != 0) {
 558                 // if drawing, cancel, otherwise pass it up for undo
 559                 if (pc->state != SP_PENCIL_CONTEXT_IDLE) {
 560                     pencil_cancel (pc);
 561                     ret = TRUE;
 562                 }
 563             }
 564             break;
 565         case GDK_g:
 566         case GDK_G:
 567             if (mod_shift_only(state)) {
 568                 sp_selection_to_guides(SP_EVENT_CONTEXT(pc)->desktop);
 569                 ret = true;
 570             }
 571             break;
 572         case GDK_Alt_L:
 573         case GDK_Alt_R:
 574         case GDK_Meta_L:
 575         case GDK_Meta_R:
 576             if (pc->state == SP_PENCIL_CONTEXT_IDLE) {
 577                 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."));
 578             }
 579             break;
 580         default:
 581             break;
 582     }
 583     return ret;
 584 }
 585
 586 static gint
 587 pencil_handle_key_release(SPPencilContext *const pc, guint const keyval, guint const /*state*/)
 588 {
 589     gint ret = FALSE;
 590     switch (keyval) {
 591         case GDK_Alt_L:
 592         case GDK_Alt_R:
 593         case GDK_Meta_L:
 594         case GDK_Meta_R:
 595             if (pc->state == SP_PENCIL_CONTEXT_SKETCH) {
 596                 spdc_concat_colors_and_flush(pc, FALSE);
 597                 pc->sketch_n = 0;
 598                 pc->sa = NULL;
 599                 pc->ea = NULL;
 600                 if (pc->green_anchor) {
 601                     pc->green_anchor = sp_draw_anchor_destroy(pc->green_anchor);
 602                 }
 603                 pc->state = SP_PENCIL_CONTEXT_IDLE;
 604                 sp_event_context_discard_delayed_snap_event(SP_EVENT_CONTEXT(pc));
 605                 pc->desktop->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Finishing freehand sketch"));
 606                 ret = TRUE;
 607             }
 608             break;
 609         default:
 610             break;
 611     }
 612     return ret;
 613 }
 614
 615 /**
 616  * Reset points and set new starting point.
 617  */
 618 static void
 619 spdc_set_startpoint(SPPencilContext *const pc, Geom::Point const p)
 620 {
 621     pc->npoints = 0;
 622     pc->red_curve_is_valid = false;
 623     if (in_svg_plane(p)) {
 624         pc->p[pc->npoints++] = p;
 625         pc->ps.push_back(p);
 626     }
 627 }
 628
 629 /**
 630  * Change moving endpoint position.
 631  * <ul>
 632  * <li>Ctrl constrains to moving to H/V direction, snapping in given direction.
 633  * <li>Otherwise we snap freely to whatever attractors are available.
 634  * </ul>
 635  *
 636  * Number of points is (re)set to 2 always, 2nd point is modified.
 637  * We change RED curve.
 638  */
 639 static void
 640 spdc_set_endpoint(SPPencilContext *const pc, Geom::Point const p)
 641 {
 642     if (pc->npoints == 0) {
 643         return;
 644         /* May occur if first point wasn't in SVG plane (e.g. weird w2d transform, perhaps from bad
 645          * zoom setting).
 646          */
 647     }
 648     g_return_if_fail( pc->npoints > 0 );
 649
 650     pc->red_curve->reset();
 651     if ( ( p == pc->p[0] )
 652          || !in_svg_plane(p) )
 653     {
 654         pc->npoints = 1;
 655     } else {
 656         pc->p[1] = p;
 657         pc->npoints = 2;
 658
 659         pc->red_curve->moveto(pc->p[0]);
 660         pc->red_curve->lineto(pc->p[1]);
 661         pc->red_curve_is_valid = true;
 662
 663         sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), pc->red_curve);
 664     }
 665 }
 666
 667 /**
 668  * Finalize addline.
 669  *
 670  * \todo
 671  * fixme: I'd like remove red reset from concat colors (lauris).
 672  * Still not sure, how it will make most sense.
 673  */
 674 static void
 675 spdc_finish_endpoint(SPPencilContext *const pc)
 676 {
 677     if ( ( pc->red_curve->is_empty() )
 678          || ( *(pc->red_curve->first_point()) == *(pc->red_curve->second_point())   ) )
 679     {
 680         pc->red_curve->reset();
 681         sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), NULL);
 682     } else {
 683         /* Write curves to object. */
 684         spdc_concat_colors_and_flush(pc, FALSE);
 685         pc->sa = NULL;
 686         pc->ea = NULL;
 687     }
 688 }
 689
 690
 691 static void
 692 spdc_add_freehand_point(SPPencilContext *pc, Geom::Point p, guint /*state*/)
 693 {
 694     g_assert( pc->npoints > 0 );
 695     g_return_if_fail(unsigned(pc->npoints) < G_N_ELEMENTS(pc->p));
 696
 697     if ( ( p != pc->p[ pc->npoints - 1 ] )
 698          && in_svg_plane(p) )
 699     {
 700         pc->ps.push_back(p);
 701         pc->p[pc->npoints++] = p;
 702         fit_and_split(pc);
 703     }
 704 }
 705
 706 static inline double
 707 square(double const x)
 708 {
 709     return x * x;
 710 }
 711
 712 static void
 713 interpolate(SPPencilContext *pc)
 714 {
 715     if ( pc->ps.size() <= 1 ) {
 716         return;
 717     }
 718
 719     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 720     double const tol = prefs->getDoubleLimited("/tools/freehand/pencil/tolerance", 10.0, 1.0, 100.0) * 0.4;
 721     double const tolerance_sq = 0.02 * square( pc->desktop->w2d().descrim() *
 722                                                tol) * exp(0.2*tol - 2);
 723
 724     g_assert(is_zero(pc->req_tangent)
 725              || is_unit_vector(pc->req_tangent));
 726     Geom::Point const tHatEnd(0, 0);
 727
 728     guint n_points  = pc->ps.size();
 729     pc->green_curve->reset();
 730     pc->red_curve->reset();
 731     pc->red_curve_is_valid = false;
 732
 733     Geom::Point * b = g_new(Geom::Point, 4*n_points);
 734     Geom::Point * points = g_new(Geom::Point, 4*n_points);
 735     for (unsigned int i = 0; i < pc->ps.size(); i++) {
 736         points[i] = pc->ps[i];
 737     }
 738
 739     // worst case gives us a segment per point
 740     int max_segs = 4*n_points;
 741
 742     int const n_segs = Geom::bezier_fit_cubic_r(b, points, n_points,
 743                                              tolerance_sq, max_segs);
 744
 745     if ( n_segs > 0)
 746     {
 747         /* Fit and draw and reset state */
 748         pc->green_curve->moveto(b[0]);
 749         for (int c = 0; c < n_segs; c++) {
 750             pc->green_curve->curveto(b[4*c+1], b[4*c+2], b[4*c+3]);
 751         }
 752         sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), pc->green_curve);
 753
 754         /* Fit and draw and copy last point */
 755         g_assert(!pc->green_curve->is_empty());
 756
 757         /* Set up direction of next curve. */
 758         {
 759             Geom::CubicBezier const * last_seg = dynamic_cast<Geom::CubicBezier const *>(pc->green_curve->last_segment());
 760             g_assert( last_seg );      // Relevance: validity of (*last_seg)[2]
 761             pc->p[0] = last_seg->finalPoint();
 762             pc->npoints = 1;
 763             Geom::Point const req_vec( pc->p[0] - (*last_seg)[2] );
 764             pc->req_tangent = ( ( Geom::is_zero(req_vec) || !in_svg_plane(req_vec) )
 765                                 ? Geom::Point(0, 0)
 766                                 : Geom::unit_vector(req_vec) );
 767         }
 768     }
 769     g_free(b);
 770     g_free(points);
 771     pc->ps.clear();
 772 }
 773
 774
 775 /* interpolates the sketched curve and tweaks the current sketch interpolation*/
 776 static void
 777 sketch_interpolate(SPPencilContext *pc)
 778 {
 779     if ( pc->ps.size() <= 1 ) {
 780         return;
 781     }
 782
 783     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 784     double const tol = prefs->getDoubleLimited("/tools/freehand/pencil/tolerance", 10.0, 1.0, 100.0) * 0.4;
 785     double const tolerance_sq = 0.02 * square( pc->desktop->w2d().descrim() *
 786                                                tol) * exp(0.2*tol - 2);
 787
 788     bool average_all_sketches = prefs->getBool("/tools/freehand/pencil/average_all_sketches", true);
 789
 790     g_assert(is_zero(pc->req_tangent)
 791              || is_unit_vector(pc->req_tangent));
 792     Geom::Point const tHatEnd(0, 0);
 793
 794     guint n_points  = pc->ps.size();
 795     pc->red_curve->reset();
 796     pc->red_curve_is_valid = false;
 797
 798     Geom::Point * b = g_new(Geom::Point, 4*n_points);
 799     Geom::Point * points = g_new(Geom::Point, 4*n_points);
 800     for (unsigned i = 0; i < pc->ps.size(); i++) {
 801         points[i] = pc->ps[i];
 802     }
 803
 804     // worst case gives us a segment per point
 805     int max_segs = 4*n_points;
 806
 807     int const n_segs = Geom::bezier_fit_cubic_r(b, points, n_points,
 808                                              tolerance_sq, max_segs);
 809
 810     if ( n_segs > 0)
 811     {
 812         Geom::Path fit(b[0]);
 813         for (int c = 0; c < n_segs; c++) {
 814             fit.appendNew<Geom::CubicBezier>(b[4*c+1], b[4*c+2], b[4*c+3]);
 815         }
 816         Geom::Piecewise<Geom::D2<Geom::SBasis> > fit_pwd2 = fit.toPwSb();
 817
 818         double t =0.;
 819         if ( pc->sketch_n > 0 ) {
 820             if (average_all_sketches) {
 821                 // Average = (sum of all) / n
 822                 //         = (sum of all + new one) / n+1
 823                 //         = ((old average)*n + new one) / n+1
 824                 t = pc->sketch_n / (pc->sketch_n + 1.);
 825             } else {
 826                 t = 0.5;
 827             }
 828             pc->sketch_interpolation = Geom::lerp(t, fit_pwd2, pc->sketch_interpolation);
 829             // simplify path, to eliminate small segments
 830             Path *path = new Path;
 831             path->LoadPathVector(Geom::path_from_piecewise(pc->sketch_interpolation, 0.01));
 832             path->Simplify(0.5);
 833             Geom::PathVector *pathv = path->MakePathVector();
 834             pc->sketch_interpolation = (*pathv)[0].toPwSb();
 835             delete path;
 836             delete pathv;
 837         } else {
 838             pc->sketch_interpolation = fit_pwd2;
 839         }
 840         pc->sketch_n++;
 841
 842         pc->green_curve->reset();
 843         pc->green_curve->set_pathvector(Geom::path_from_piecewise(pc->sketch_interpolation, 0.01));
 844         sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), pc->green_curve);
 845
 846         /* Fit and draw and copy last point */
 847         g_assert(!pc->green_curve->is_empty());
 848
 849         /* Set up direction of next curve. */
 850         {
 851             Geom::CubicBezier const * last_seg = dynamic_cast<Geom::CubicBezier const *>(pc->green_curve->last_segment());
 852             g_assert( last_seg );      // Relevance: validity of (*last_seg)[2]
 853             pc->p[0] = last_seg->finalPoint();
 854             pc->npoints = 1;
 855             Geom::Point const req_vec( pc->p[0] - (*last_seg)[2] );
 856             pc->req_tangent = ( ( Geom::is_zero(req_vec) || !in_svg_plane(req_vec) )
 857                                 ? Geom::Point(0, 0)
 858                                 : Geom::unit_vector(req_vec) );
 859         }
 860     }
 861     g_free(b);
 862     g_free(points);
 863     pc->ps.clear();
 864 }
 865
 866 static void
 867 fit_and_split(SPPencilContext *pc)
 868 {
 869     g_assert( pc->npoints > 1 );
 870
 871     double const tolerance_sq = 0;
 872
 873     Geom::Point b[4];
 874     g_assert(is_zero(pc->req_tangent)
 875              || is_unit_vector(pc->req_tangent));
 876     Geom::Point const tHatEnd(0, 0);
 877     int const n_segs = Geom::bezier_fit_cubic_full(b, NULL, pc->p, pc->npoints,
 878                                                 pc->req_tangent, tHatEnd,
 879                                                 tolerance_sq, 1);
 880     if ( n_segs > 0
 881          && unsigned(pc->npoints) < G_N_ELEMENTS(pc->p) )
 882     {
 883         /* Fit and draw and reset state */
 884         pc->red_curve->reset();
 885         pc->red_curve->moveto(b[0]);
 886         pc->red_curve->curveto(b[1], b[2], b[3]);
 887         sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), pc->red_curve);
 888         pc->red_curve_is_valid = true;
 889     } else {
 890         /* Fit and draw and copy last point */
 891
 892         g_assert(!pc->red_curve->is_empty());
 893
 894         /* Set up direction of next curve. */
 895         {
 896             Geom::CubicBezier const * last_seg = dynamic_cast<Geom::CubicBezier const *>(pc->red_curve->last_segment());
 897             g_assert( last_seg );      // Relevance: validity of (*last_seg)[2]
 898             pc->p[0] = last_seg->finalPoint();
 899             pc->npoints = 1;
 900             Geom::Point const req_vec( pc->p[0] - (*last_seg)[2] );
 901             pc->req_tangent = ( ( Geom::is_zero(req_vec) || !in_svg_plane(req_vec) )
 902                                 ? Geom::Point(0, 0)
 903                                 : Geom::unit_vector(req_vec) );
 904         }
 905
 906         pc->green_curve->append_continuous(pc->red_curve, 0.0625);
 907         SPCurve *curve = pc->red_curve->copy();
 908
 909         /// \todo fixme:
 910         SPCanvasItem *cshape = sp_canvas_bpath_new(sp_desktop_sketch(pc->desktop), curve);
 911         curve->unref();
 912         sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(cshape), pc->green_color, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 913
 914         pc->green_bpaths = g_slist_prepend(pc->green_bpaths, cshape);
 915
 916         pc->red_curve_is_valid = false;
 917     }
 918 }
 919
 920
 921 /*
 922   Local Variables:
 923   mode:c++
 924   c-file-style:"stroustrup"
 925   c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
 926   indent-tabs-mode:nil
 927   fill-column:99
 928   End:
 929 */
 930 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :