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 "prefs-utils.h"
  31 #include "snap.h"
  32 #include "pixmaps/cursor-pencil.xpm"
  33 #include "display/bezier-utils.h"
  34 #include "display/canvas-bpath.h"
  35 #include <glibmm/i18n.h>
  36 #include "libnr/in-svg-plane.h"
  37 #include "context-fns.h"
  38 #include "sp-namedview.h"
  39 #include "xml/repr.h"
  40 #include "document.h"
  41 #include "desktop-style.h"
  42 #include "macros.h"
  43 #include "display/curve.h"
  44
  45 static void sp_pencil_context_class_init(SPPencilContextClass *klass);
  46 static void sp_pencil_context_init(SPPencilContext *pc);
  47 static void sp_pencil_context_setup(SPEventContext *ec);
  48 static void sp_pencil_context_dispose(GObject *object);
  49
  50 static gint sp_pencil_context_root_handler(SPEventContext *event_context, GdkEvent *event);
  51 static gint pencil_handle_button_press(SPPencilContext *const pc, GdkEventButton const &bevent);
  52 static gint pencil_handle_motion_notify(SPPencilContext *const pc, GdkEventMotion const &mevent);
  53 static gint pencil_handle_button_release(SPPencilContext *const pc, GdkEventButton const &revent);
  54 static gint pencil_handle_key_press(SPPencilContext *const pc, guint const keyval, guint const state);
  55
  56 static void spdc_set_startpoint(SPPencilContext *pc, NR::Point const p);
  57 static void spdc_set_endpoint(SPPencilContext *pc, NR::Point const p);
  58 static void spdc_finish_endpoint(SPPencilContext *pc);
  59 static void spdc_add_freehand_point(SPPencilContext *pc, NR::Point p, guint state);
  60 static void fit_and_split(SPPencilContext *pc);
  61
  62
  63 static SPDrawContextClass *pencil_parent_class;
  64 static NR::Point pencil_drag_origin_w(0, 0);
  65 static bool pencil_within_tolerance = false;
  66
  67 /**
  68  * Register SPPencilContext class with Gdk and return its type number.
  69  */
  70 GType
  71 sp_pencil_context_get_type()
  72 {
  73     static GType type = 0;
  74     if (!type) {
  75         GTypeInfo info = {
  76             sizeof(SPPencilContextClass),
  77             NULL, NULL,
  78             (GClassInitFunc) sp_pencil_context_class_init,
  79             NULL, NULL,
  80             sizeof(SPPencilContext),
  81             4,
  82             (GInstanceInitFunc) sp_pencil_context_init,
  83             NULL,   /* value_table */
  84         };
  85         type = g_type_register_static(SP_TYPE_DRAW_CONTEXT, "SPPencilContext", &info, (GTypeFlags)0);
  86     }
  87     return type;
  88 }
  89
  90 /**
  91  * Initialize SPPencilContext vtable.
  92  */
  93 static void
  94 sp_pencil_context_class_init(SPPencilContextClass *klass)
  95 {
  96     GObjectClass *object_class;
  97     SPEventContextClass *event_context_class;
  98
  99     object_class = (GObjectClass *) klass;
 100     event_context_class = (SPEventContextClass *) klass;
 101
 102     pencil_parent_class = (SPDrawContextClass*)g_type_class_peek_parent(klass);
 103
 104     object_class->dispose = sp_pencil_context_dispose;
 105
 106     event_context_class->setup = sp_pencil_context_setup;
 107     event_context_class->root_handler = sp_pencil_context_root_handler;
 108 }
 109
 110 /**
 111  * Callback to initialize SPPencilContext object.
 112  */
 113 static void
 114 sp_pencil_context_init(SPPencilContext *pc)
 115 {
 116     SPEventContext *event_context = SP_EVENT_CONTEXT(pc);
 117
 118     event_context->cursor_shape = cursor_pencil_xpm;
 119     event_context->hot_x = 4;
 120     event_context->hot_y = 4;
 121
 122     pc->npoints = 0;
 123     pc->state = SP_PENCIL_CONTEXT_IDLE;
 124     pc->req_tangent = NR::Point(0, 0);
 125 }
 126
 127 /**
 128  * Callback to setup SPPencilContext object.
 129  */
 130 static void
 131 sp_pencil_context_setup(SPEventContext *ec)
 132 {
 133     if (prefs_get_int_attribute("tools.freehand.pencil", "selcue", 0) != 0) {
 134         ec->enableSelectionCue();
 135     }
 136
 137     if (((SPEventContextClass *) pencil_parent_class)->setup) {
 138         ((SPEventContextClass *) pencil_parent_class)->setup(ec);
 139     }
 140
 141     SPPencilContext *const pc = SP_PENCIL_CONTEXT(ec);
 142     pc->is_drawing = false;
 143
 144     pc->anchor_statusbar = false;
 145 }
 146
 147 static void
 148 sp_pencil_context_dispose(GObject *object)
 149 {
 150     G_OBJECT_CLASS(pencil_parent_class)->dispose(object);
 151 }
 152
 153 /** Snaps new node relative to the previous node. */
 154 static void
 155 spdc_endpoint_snap(SPPencilContext const *pc, NR::Point &p, guint const state)
 156 {
 157     spdc_endpoint_snap_rotation(pc, p, pc->p[0], state);
 158     spdc_endpoint_snap_free(pc, p, state);
 159 }
 160
 161 /**
 162  * Callback for handling all pencil context events.
 163  */
 164 gint
 165 sp_pencil_context_root_handler(SPEventContext *const ec, GdkEvent *event)
 166 {
 167     SPPencilContext *const pc = SP_PENCIL_CONTEXT(ec);
 168
 169     gint ret = FALSE;
 170
 171     switch (event->type) {
 172         case GDK_BUTTON_PRESS:
 173             ret = pencil_handle_button_press(pc, event->button);
 174             break;
 175
 176         case GDK_MOTION_NOTIFY:
 177             ret = pencil_handle_motion_notify(pc, event->motion);
 178             break;
 179
 180         case GDK_BUTTON_RELEASE:
 181             ret = pencil_handle_button_release(pc, event->button);
 182             break;
 183
 184         case GDK_KEY_PRESS:
 185             ret = pencil_handle_key_press(pc, get_group0_keyval (&event->key), event->key.state);
 186             break;
 187
 188         default:
 189             break;
 190     }
 191
 192     if (!ret) {
 193         gint (*const parent_root_handler)(SPEventContext *, GdkEvent *)
 194             = ((SPEventContextClass *) pencil_parent_class)->root_handler;
 195         if (parent_root_handler) {
 196             ret = parent_root_handler(ec, event);
 197         }
 198     }
 199
 200     return ret;
 201 }
 202
 203 static gint
 204 pencil_handle_button_press(SPPencilContext *const pc, GdkEventButton const &bevent)
 205 {
 206     gint ret = FALSE;
 207     SPEventContext *event_context = SP_EVENT_CONTEXT(pc);
 208     if ( bevent.button == 1  && !event_context->space_panning) {
 209
 210         SPDrawContext *dc = SP_DRAW_CONTEXT (pc);
 211         SPDesktop *desktop = SP_EVENT_CONTEXT_DESKTOP(dc);
 212         Inkscape::Selection *selection = sp_desktop_selection(desktop);
 213
 214         if (Inkscape::have_viable_layer(desktop, dc->_message_context) == false) {
 215             return TRUE;
 216         }
 217
 218         NR::Point const button_w(bevent.x, bevent.y);
 219
 220         /* Find desktop coordinates */
 221         NR::Point p = pc->desktop->w2d(button_w);
 222
 223         /* Test whether we hit any anchor. */
 224         SPDrawAnchor *anchor = spdc_test_inside(pc, button_w);
 225
 226         pencil_drag_origin_w = NR::Point(bevent.x,bevent.y);
 227         pencil_within_tolerance = true;
 228
 229         switch (pc->state) {
 230             case SP_PENCIL_CONTEXT_ADDLINE:
 231                 /* Current segment will be finished with release */
 232                 ret = TRUE;
 233                 break;
 234             default:
 235                 /* Set first point of sequence */
 236                 if (bevent.state & GDK_CONTROL_MASK) {
 237                     freehand_create_single_dot(event_context, p, "tools.freehand.pencil", bevent.state);
 238                     ret = true;
 239                     break;
 240                 }
 241                 if (anchor) {
 242                     p = anchor->dp;
 243                     desktop->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Continuing selected path"));
 244                 } else {
 245
 246                     if (!(bevent.state & GDK_SHIFT_MASK)) {
 247
 248                         // This is the first click of a new curve; deselect item so that
 249                         // this curve is not combined with it (unless it is drawn from its
 250                         // anchor, which is handled by the sibling branch above)
 251                         selection->clear();
 252                         desktop->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Creating new path"));
 253                         SnapManager &m = desktop->namedview->snap_manager;
 254                         m.setup(desktop);
 255                         m.freeSnapReturnByRef(Inkscape::Snapper::SNAPPOINT_NODE, p);
 256                     } else if (selection->singleItem() && SP_IS_PATH(selection->singleItem())) {
 257                         desktop->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Appending to selected path"));
 258                     }
 259                 }
 260                 pc->sa = anchor;
 261                 spdc_set_startpoint(pc, p);
 262                 ret = TRUE;
 263                 break;
 264         }
 265
 266         pc->is_drawing = true;
 267     }
 268     return ret;
 269 }
 270
 271 static gint
 272 pencil_handle_motion_notify(SPPencilContext *const pc, GdkEventMotion const &mevent)
 273 {
 274     if ((mevent.state & GDK_CONTROL_MASK) && (mevent.state & GDK_BUTTON1_MASK)) {
 275         // mouse was accidentally moved during Ctrl+click;
 276         // ignore the motion and create a single point
 277         pc->is_drawing = false;
 278         return TRUE;
 279     }
 280     gint ret = FALSE;
 281     SPDesktop *const dt = pc->desktop;
 282
 283     SPEventContext *event_context = SP_EVENT_CONTEXT(pc);
 284     if (event_context->space_panning || mevent.state & GDK_BUTTON2_MASK || mevent.state & GDK_BUTTON3_MASK) {
 285         // allow scrolling
 286         return FALSE;
 287     }
 288
 289     if ( ( mevent.state & GDK_BUTTON1_MASK ) && !pc->grab && pc->is_drawing) {
 290         /* Grab mouse, so release will not pass unnoticed */
 291         pc->grab = SP_CANVAS_ITEM(dt->acetate);
 292         sp_canvas_item_grab(pc->grab, ( GDK_KEY_PRESS_MASK | GDK_BUTTON_PRESS_MASK   |
 293                                         GDK_BUTTON_RELEASE_MASK |
 294                                         GDK_POINTER_MOTION_MASK  ),
 295                             NULL, mevent.time);
 296     }
 297
 298     /* Find desktop coordinates */
 299     NR::Point p = dt->w2d(NR::Point(mevent.x, mevent.y));
 300
 301     /* Test whether we hit any anchor. */
 302     SPDrawAnchor *anchor = spdc_test_inside(pc, NR::Point(mevent.x, mevent.y));
 303
 304     if (pencil_within_tolerance) {
 305         gint const tolerance = prefs_get_int_attribute_limited("options.dragtolerance",
 306                                                                "value", 0, 0, 100);
 307         if ( NR::LInfty( NR::Point(mevent.x,mevent.y) - pencil_drag_origin_w ) < tolerance ) {
 308             return FALSE;   // Do not drag if we're within tolerance from origin.
 309         }
 310     }
 311
 312     // Once the user has moved farther than tolerance from the original location
 313     // (indicating they intend to move the object, not click), then always process the
 314     // motion notify coordinates as given (no snapping back to origin)
 315     pencil_within_tolerance = false;
 316
 317     switch (pc->state) {
 318         case SP_PENCIL_CONTEXT_ADDLINE:
 319             /* Set red endpoint */
 320             if (anchor) {
 321                 p = anchor->dp;
 322             } else {
 323                 spdc_endpoint_snap(pc, p, mevent.state);
 324             }
 325             spdc_set_endpoint(pc, p);
 326             ret = TRUE;
 327             break;
 328         default:
 329             /* We may be idle or already freehand */
 330             if ( mevent.state & GDK_BUTTON1_MASK && pc->is_drawing ) {
 331                 pc->state = SP_PENCIL_CONTEXT_FREEHAND;
 332                 if ( !pc->sa && !pc->green_anchor ) {
 333                     /* Create green anchor */
 334                     pc->green_anchor = sp_draw_anchor_new(pc, pc->green_curve, TRUE, pc->p[0]);
 335                 }
 336                 /** \todo
 337                  * fixme: I am not sure whether we want to snap to anchors
 338                  * in middle of freehand (Lauris)
 339                  */
 340                 if (anchor) {
 341                     p = anchor->dp;
 342                 } else if ((mevent.state & GDK_SHIFT_MASK) == 0) {
 343                     SnapManager &m = dt->namedview->snap_manager;
 344                     m.setup(dt, NULL);
 345                     m.freeSnapReturnByRef(Inkscape::Snapper::SNAPPOINT_NODE, p);
 346                 }
 347                 if ( pc->npoints != 0 ) { // buttonpress may have happened before we entered draw context!
 348                     spdc_add_freehand_point(pc, p, mevent.state);
 349                     ret = TRUE;
 350                 }
 351
 352                 if (anchor && !pc->anchor_statusbar) {
 353                     pc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("<b>Release</b> here to close and finish the path."));
 354                     pc->anchor_statusbar = true;
 355                 } else if (!anchor && pc->anchor_statusbar) {
 356                     pc->_message_context->clear();
 357                     pc->anchor_statusbar = false;
 358                 } else if (!anchor) {
 359                     pc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("Drawing a freehand path"));
 360                 }
 361
 362             } else {
 363                 if (anchor && !pc->anchor_statusbar) {
 364                     pc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("<b>Drag</b> to continue the path from this point."));
 365                     pc->anchor_statusbar = true;
 366                 } else if (!anchor && pc->anchor_statusbar) {
 367                     pc->_message_context->clear();
 368                     pc->anchor_statusbar = false;
 369                 }
 370             }
 371             break;
 372     }
 373     return ret;
 374 }
 375
 376 static gint
 377 pencil_handle_button_release(SPPencilContext *const pc, GdkEventButton const &revent)
 378 {
 379     gint ret = FALSE;
 380
 381     SPEventContext *event_context = SP_EVENT_CONTEXT(pc);
 382     if ( revent.button == 1 && pc->is_drawing && !event_context->space_panning) {
 383         SPDesktop *const dt = pc->desktop;
 384
 385         pc->is_drawing = false;
 386
 387         /* Find desktop coordinates */
 388         NR::Point p = dt->w2d(NR::Point(revent.x, revent.y));
 389
 390         /* Test whether we hit any anchor. */
 391         SPDrawAnchor *anchor = spdc_test_inside(pc, NR::Point(revent.x,
 392                                                               revent.y));
 393
 394         switch (pc->state) {
 395             case SP_PENCIL_CONTEXT_IDLE:
 396                 /* Releasing button in idle mode means single click */
 397                 /* We have already set up start point/anchor in button_press */
 398                 if (!(revent.state & GDK_CONTROL_MASK)) {
 399                     // Ctrl+click creates a single point so only set context in ADDLINE mode when Ctrl isn't pressed
 400                     pc->state = SP_PENCIL_CONTEXT_ADDLINE;
 401                 }
 402                 ret = TRUE;
 403                 break;
 404             case SP_PENCIL_CONTEXT_ADDLINE:
 405                 /* Finish segment now */
 406                 if (anchor) {
 407                     p = anchor->dp;
 408                 } else {
 409                     spdc_endpoint_snap(pc, p, revent.state);
 410                 }
 411                 pc->ea = anchor;
 412                 spdc_set_endpoint(pc, p);
 413                 spdc_finish_endpoint(pc);
 414                 pc->state = SP_PENCIL_CONTEXT_IDLE;
 415                 ret = TRUE;
 416                 break;
 417             case SP_PENCIL_CONTEXT_FREEHAND:
 418                 /* Finish segment now */
 419                 /// \todo fixme: Clean up what follows (Lauris)
 420                 if (anchor) {
 421                     p = anchor->dp;
 422                 }
 423                 pc->ea = anchor;
 424                 /* Write curves to object */
 425
 426                 dt->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Finishing freehand"));
 427
 428                 spdc_concat_colors_and_flush(pc, FALSE);
 429                 pc->sa = NULL;
 430                 pc->ea = NULL;
 431                 if (pc->green_anchor) {
 432                     pc->green_anchor = sp_draw_anchor_destroy(pc->green_anchor);
 433                 }
 434                 pc->state = SP_PENCIL_CONTEXT_IDLE;
 435                 ret = TRUE;
 436                 break;
 437             default:
 438                 break;
 439         }
 440
 441         if (pc->grab) {
 442             /* Release grab now */
 443             sp_canvas_item_ungrab(pc->grab, revent.time);
 444             pc->grab = NULL;
 445         }
 446
 447         ret = TRUE;
 448     }
 449     return ret;
 450 }
 451
 452 static void
 453 pencil_cancel (SPPencilContext *const pc)
 454 {
 455     if (pc->grab) {
 456         /* Release grab now */
 457         sp_canvas_item_ungrab(pc->grab, 0);
 458         pc->grab = NULL;
 459     }
 460
 461     pc->is_drawing = false;
 462
 463     pc->state = SP_PENCIL_CONTEXT_IDLE;
 464
 465     pc->red_curve->reset();
 466     sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), NULL);
 467     while (pc->green_bpaths) {
 468         gtk_object_destroy(GTK_OBJECT(pc->green_bpaths->data));
 469         pc->green_bpaths = g_slist_remove(pc->green_bpaths, pc->green_bpaths->data);
 470     }
 471     pc->green_curve->reset();
 472     if (pc->green_anchor) {
 473         pc->green_anchor = sp_draw_anchor_destroy(pc->green_anchor);
 474     }
 475
 476     pc->_message_context->clear();
 477     pc->_message_context->flash(Inkscape::NORMAL_MESSAGE, _("Drawing cancelled"));
 478
 479     sp_canvas_end_forced_full_redraws(pc->desktop->canvas);
 480 }
 481
 482
 483 static gint
 484 pencil_handle_key_press(SPPencilContext *const pc, guint const keyval, guint const state)
 485 {
 486     gint ret = FALSE;
 487     switch (keyval) {
 488         case GDK_Up:
 489         case GDK_Down:
 490         case GDK_KP_Up:
 491         case GDK_KP_Down:
 492             // Prevent the zoom field from activation.
 493             if (!mod_ctrl_only(state)) {
 494                 ret = TRUE;
 495             }
 496             break;
 497         case GDK_Escape:
 498             if (pc->npoints != 0) {
 499                 // if drawing, cancel, otherwise pass it up for deselecting
 500                 if (pc->is_drawing) {
 501                     pencil_cancel (pc);
 502                     ret = TRUE;
 503                 }
 504             }
 505             break;
 506         case GDK_z:
 507         case GDK_Z:
 508             if (mod_ctrl_only(state) && pc->npoints != 0) {
 509                 // if drawing, cancel, otherwise pass it up for undo
 510                 if (pc->is_drawing) {
 511                     pencil_cancel (pc);
 512                     ret = TRUE;
 513                 }
 514             }
 515             break;
 516         case GDK_g:
 517         case GDK_G:
 518             if (mod_shift_only(state)) {
 519                 sp_selection_to_guides();
 520                 ret = true;
 521             }
 522             break;
 523         default:
 524             break;
 525     }
 526     return ret;
 527 }
 528
 529 /**
 530  * Reset points and set new starting point.
 531  */
 532 static void
 533 spdc_set_startpoint(SPPencilContext *const pc, NR::Point const p)
 534 {
 535     pc->npoints = 0;
 536     pc->red_curve_is_valid = false;
 537     if (in_svg_plane(p)) {
 538         pc->p[pc->npoints++] = p;
 539     }
 540 }
 541
 542 /**
 543  * Change moving endpoint position.
 544  * <ul>
 545  * <li>Ctrl constrains to moving to H/V direction, snapping in given direction.
 546  * <li>Otherwise we snap freely to whatever attractors are available.
 547  * </ul>
 548  *
 549  * Number of points is (re)set to 2 always, 2nd point is modified.
 550  * We change RED curve.
 551  */
 552 static void
 553 spdc_set_endpoint(SPPencilContext *const pc, NR::Point const p)
 554 {
 555     if (pc->npoints == 0) {
 556         return;
 557         /* May occur if first point wasn't in SVG plane (e.g. weird w2d transform, perhaps from bad
 558          * zoom setting).
 559          */
 560     }
 561     g_return_if_fail( pc->npoints > 0 );
 562
 563     pc->red_curve->reset();
 564     if ( ( p == pc->p[0] )
 565          || !in_svg_plane(p) )
 566     {
 567         pc->npoints = 1;
 568     } else {
 569         pc->p[1] = p;
 570         pc->npoints = 2;
 571
 572         pc->red_curve->moveto(pc->p[0]);
 573         pc->red_curve->lineto(pc->p[1]);
 574         pc->red_curve_is_valid = true;
 575
 576         sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), pc->red_curve);
 577     }
 578 }
 579
 580 /**
 581  * Finalize addline.
 582  *
 583  * \todo
 584  * fixme: I'd like remove red reset from concat colors (lauris).
 585  * Still not sure, how it will make most sense.
 586  */
 587 static void
 588 spdc_finish_endpoint(SPPencilContext *const pc)
 589 {
 590     if ( ( pc->red_curve->is_empty() )
 591          || ( pc->red_curve->first_point() == pc->red_curve->second_point()   ) )
 592     {
 593         pc->red_curve->reset();
 594         sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), NULL);
 595     } else {
 596         /* Write curves to object. */
 597         spdc_concat_colors_and_flush(pc, FALSE);
 598         pc->sa = NULL;
 599         pc->ea = NULL;
 600     }
 601 }
 602
 603 static void
 604 spdc_add_freehand_point(SPPencilContext *pc, NR::Point p, guint /*state*/)
 605 {
 606     g_assert( pc->npoints > 0 );
 607     g_return_if_fail(unsigned(pc->npoints) < G_N_ELEMENTS(pc->p));
 608
 609     if ( ( p != pc->p[ pc->npoints - 1 ] )
 610          && in_svg_plane(p) )
 611     {
 612         pc->p[pc->npoints++] = p;
 613         fit_and_split(pc);
 614     }
 615 }
 616
 617 static inline double
 618 square(double const x)
 619 {
 620     return x * x;
 621 }
 622
 623 static void
 624 fit_and_split(SPPencilContext *pc)
 625 {
 626     g_assert( pc->npoints > 1 );
 627
 628     double const tol = prefs_get_double_attribute_limited("tools.freehand.pencil",                                                                             "tolerance", 10.0, 1.0, 100.0);
 629     double const tolerance_sq = 0.02 * square( NR::expansion(pc->desktop->w2d()) * tol)
 630         * exp(0.2*tol - 2);
 631
 632     NR::Point b[4];
 633     g_assert(is_zero(pc->req_tangent)
 634              || is_unit_vector(pc->req_tangent));
 635     NR::Point const tHatEnd(0, 0);
 636     int const n_segs = sp_bezier_fit_cubic_full(b, NULL, pc->p, pc->npoints,
 637                                                 pc->req_tangent, tHatEnd, tolerance_sq, 1);
 638     if ( n_segs > 0
 639          && unsigned(pc->npoints) < G_N_ELEMENTS(pc->p) )
 640     {
 641         /* Fit and draw and reset state */
 642         pc->red_curve->reset();
 643         pc->red_curve->moveto(b[0]);
 644         pc->red_curve->curveto(b[1], b[2], b[3]);
 645         sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), pc->red_curve);
 646         pc->red_curve_is_valid = true;
 647     } else {
 648         /* Fit and draw and copy last point */
 649
 650         g_assert(!pc->red_curve->is_empty());
 651
 652         /* Set up direction of next curve. */
 653         {
 654             Geom::CubicBezier const * last_seg = dynamic_cast<Geom::CubicBezier const *>(pc->red_curve->last_segment());
 655             g_assert( last_seg );      // Relevance: validity of (*last_seg)[2]
 656             pc->p[0] = last_seg->finalPoint();
 657             pc->npoints = 1;
 658             NR::Point const req_vec( pc->p[0] - (*last_seg)[2] );
 659             pc->req_tangent = ( ( NR::is_zero(req_vec) || !in_svg_plane(req_vec) )
 660                                 ? NR::Point(0, 0)
 661                                 : NR::unit_vector(req_vec) );
 662         }
 663
 664         pc->green_curve->append_continuous(pc->red_curve, 0.0625);
 665         SPCurve *curve = pc->red_curve->copy();
 666
 667         /// \todo fixme:
 668         SPCanvasItem *cshape = sp_canvas_bpath_new(sp_desktop_sketch(pc->desktop), curve);
 669         curve->unref();
 670         sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(cshape), pc->green_color, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 671
 672         pc->green_bpaths = g_slist_prepend(pc->green_bpaths, cshape);
 673
 674         pc->red_curve_is_valid = false;
 675     }
 676 }
 677
 678
 679 /*
 680   Local Variables:
 681   mode:c++
 682   c-file-style:"stroustrup"
 683   c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
 684   indent-tabs-mode:nil
 685   fill-column:99
 686   End:
 687 */
 688 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :