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