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