src/pencil-context.cpp

   1 /** \file
   2  * Pencil event context implementation.
   3  */
   4
   5 /*
   6  * Authors:
   7  *   Lauris Kaplinski <lauris@kaplinski.com>
   8  *   bulia byak <buliabyak@users.sf.net>
   9  *
  10  * Copyright (C) 2000 Lauris Kaplinski
  11  * Copyright (C) 2000-2001 Ximian, Inc.
  12  * Copyright (C) 2002 Lauris Kaplinski
  13  * Copyright (C) 2004 Monash University
  14  *
  15  * Released under GNU GPL, read the file 'COPYING' for more information
  16  */
  17
  18 #include <gdk/gdkkeysyms.h>
  19
  20 #include "pencil-context.h"
  21 #include "desktop.h"
  22 #include "desktop-handles.h"
  23 #include "selection.h"
  24 #include "selection-chemistry.h"
  25 #include "draw-anchor.h"
  26 #include "message-stack.h"
  27 #include "message-context.h"
  28 #include "modifier-fns.h"
  29 #include "sp-path.h"
  30 #include "preferences.h"
  31 #include "snap.h"
  32 #include "pixmaps/cursor-pencil.xpm"
  33 #include <2geom/sbasis-to-bezier.h>
  34 #include <2geom/bezier-utils.h>
  35 #include "display/canvas-bpath.h"
  36 #include <glibmm/i18n.h>
  37 #include "libnr/in-svg-plane.h"
  38 #include "context-fns.h"
  39 #include "sp-namedview.h"
  40 #include "xml/repr.h"
  41 #include "document.h"
  42 #include "desktop-style.h"
  43 #include "macros.h"
  44 #include "display/curve.h"
  45 #include "livarot/Path.h"
  46
  47 static void sp_pencil_context_class_init(SPPencilContextClass *klass);
  48 static void sp_pencil_context_init(SPPencilContext *pc);
  49 static void sp_pencil_context_setup(SPEventContext *ec);
  50 static void sp_pencil_context_dispose(GObject *object);
  51
  52 static gint sp_pencil_context_root_handler(SPEventContext *event_context, GdkEvent *event);
  53 static gint pencil_handle_button_press(SPPencilContext *const pc, GdkEventButton const &bevent);
  54 static gint pencil_handle_motion_notify(SPPencilContext *const pc, GdkEventMotion const &mevent);
  55 static gint pencil_handle_button_release(SPPencilContext *const pc, GdkEventButton const &revent);
  56 static gint pencil_handle_key_press(SPPencilContext *const pc, guint const keyval, guint const state);
  57 static gint pencil_handle_key_release(SPPencilContext *const pc, guint const keyval, guint const state);
  58
  59 static void spdc_set_startpoint(SPPencilContext *pc, Geom::Point const p);
  60 static void spdc_set_endpoint(SPPencilContext *pc, Geom::Point const p);
  61 static void spdc_finish_endpoint(SPPencilContext *pc);
  62 static void spdc_add_freehand_point(SPPencilContext *pc, Geom::Point p, guint state);
  63 static void fit_and_split(SPPencilContext *pc);
  64 static void interpolate(SPPencilContext *pc);
  65 static void sketch_interpolate(SPPencilContext *pc);
  66
  67 static SPDrawContextClass *pencil_parent_class;
  68 static Geom::Point pencil_drag_origin_w(0, 0);
  69 static bool pencil_within_tolerance = false;
  70
  71 /**
  72  * Register SPPencilContext class with Gdk and return its type number.
  73  */
  74 GType
  75 sp_pencil_context_get_type()
  76 {
  77     static GType type = 0;
  78     if (!type) {
  79         GTypeInfo info = {
  80             sizeof(SPPencilContextClass),
  81             NULL, NULL,
  82             (GClassInitFunc) sp_pencil_context_class_init,
  83             NULL, NULL,
  84             sizeof(SPPencilContext),
  85             4,
  86             (GInstanceInitFunc) sp_pencil_context_init,
  87             NULL,   /* value_table */
  88         };
  89         type = g_type_register_static(SP_TYPE_DRAW_CONTEXT, "SPPencilContext", &info, (GTypeFlags)0);
  90     }
  91     return type;
  92 }
  93
  94 /**
  95  * Initialize SPPencilContext vtable.
  96  */
  97 static void
  98 sp_pencil_context_class_init(SPPencilContextClass *klass)
  99 {
 100     GObjectClass *object_class;
 101     SPEventContextClass *event_context_class;
 102
 103     object_class = (GObjectClass *) klass;
 104     event_context_class = (SPEventContextClass *) klass;
 105
 106     pencil_parent_class = (SPDrawContextClass*)g_type_class_peek_parent(klass);
 107
 108     object_class->dispose = sp_pencil_context_dispose;
 109
 110     event_context_class->setup = sp_pencil_context_setup;
 111     event_context_class->root_handler = sp_pencil_context_root_handler;
 112 }
 113
 114 /**
 115  * Callback to initialize SPPencilContext object.
 116  */
 117 static void
 118 sp_pencil_context_init(SPPencilContext *pc)
 119 {
 120     SPEventContext *event_context = SP_EVENT_CONTEXT(pc);
 121
 122     event_context->cursor_shape = cursor_pencil_xpm;
 123     event_context->hot_x = 4;
 124     event_context->hot_y = 4;
 125
 126     pc->npoints = 0;
 127     pc->state = SP_PENCIL_CONTEXT_IDLE;
 128     pc->req_tangent = Geom::Point(0, 0);
 129
 130     // since SPPencilContext is not properly constructed...
 131     pc->sketch_interpolation = Geom::Piecewise<Geom::D2<Geom::SBasis> >();
 132     pc->sketch_n = 0;
 133 }
 134
 135 /**
 136  * Callback to setup SPPencilContext object.
 137  */
 138 static void
 139 sp_pencil_context_setup(SPEventContext *ec)
 140 {
 141     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 142     if (prefs->getBool("/tools/freehand/pencil/selcue")) {
 143         ec->enableSelectionCue();
 144     }
 145
 146     if (((SPEventContextClass *) pencil_parent_class)->setup) {
 147         ((SPEventContextClass *) pencil_parent_class)->setup(ec);
 148     }
 149
 150     SPPencilContext *const pc = SP_PENCIL_CONTEXT(ec);
 151     pc->is_drawing = false;
 152
 153     pc->anchor_statusbar = false;
 154 }
 155
 156 static void
 157 sp_pencil_context_dispose(GObject *object)
 158 {
 159     G_OBJECT_CLASS(pencil_parent_class)->dispose(object);
 160 }
 161
 162 /** Snaps new node relative to the previous node. */
 163 static void
 164 spdc_endpoint_snap(SPPencilContext const *pc, Geom::Point &p, guint const state)
 165 {
 166     if ((state & GDK_CONTROL_MASK)) { //CTRL enables constrained snapping
 167         spdc_endpoint_snap_rotation(pc, p, pc->p[0], state);
 168     } else {
 169         if (!(state & GDK_SHIFT_MASK)) { //SHIFT disables all snapping, except the angular snapping above
 170                                          //After all, the user explicitely asked for angular snapping by
 171                                          //pressing CTRL
 172             spdc_endpoint_snap_free(pc, p, state);
 173         }
 174     }
 175 }
 176
 177 /**
 178  * Callback for handling all pencil context events.
 179  */
 180 gint
 181 sp_pencil_context_root_handler(SPEventContext *const ec, GdkEvent *event)
 182 {
 183     SPPencilContext *const pc = SP_PENCIL_CONTEXT(ec);
 184
 185     gint ret = FALSE;
 186
 187     switch (event->type) {
 188         case GDK_BUTTON_PRESS:
 189             ret = pencil_handle_button_press(pc, event->button);
 190             break;
 191
 192         case GDK_MOTION_NOTIFY:
 193             ret = pencil_handle_motion_notify(pc, event->motion);
 194             break;
 195
 196         case GDK_BUTTON_RELEASE:
 197             ret = pencil_handle_button_release(pc, event->button);
 198             break;
 199
 200         case GDK_KEY_PRESS:
 201             ret = pencil_handle_key_press(pc, get_group0_keyval (&event->key), event->key.state);
 202             break;
 203
 204         case GDK_KEY_RELEASE:
 205             ret = pencil_handle_key_release(pc, get_group0_keyval (&event->key), event->key.state);
 206             break;
 207
 208         default:
 209             break;
 210     }
 211
 212     if (!ret) {
 213         gint (*const parent_root_handler)(SPEventContext *, GdkEvent *)
 214             = ((SPEventContextClass *) pencil_parent_class)->root_handler;
 215         if (parent_root_handler) {
 216             ret = parent_root_handler(ec, event);
 217         }
 218     }
 219
 220     return ret;
 221 }
 222
 223 static gint
 224 pencil_handle_button_press(SPPencilContext *const pc, GdkEventButton const &bevent)
 225 {
 226     gint ret = FALSE;
 227     SPEventContext *event_context = SP_EVENT_CONTEXT(pc);
 228     if ( bevent.button == 1  && !event_context->space_panning) {
 229
 230         SPDrawContext *dc = SP_DRAW_CONTEXT (pc);
 231         SPDesktop *desktop = SP_EVENT_CONTEXT_DESKTOP(dc);
 232         Inkscape::Selection *selection = sp_desktop_selection(desktop);
 233
 234         if (Inkscape::have_viable_layer(desktop, dc->_message_context) == false) {
 235             return TRUE;
 236         }
 237
 238         if (!pc->grab) {
 239             /* Grab mouse, so release will not pass unnoticed */
 240             pc->grab = SP_CANVAS_ITEM(desktop->acetate);
 241             sp_canvas_item_grab(pc->grab, ( GDK_KEY_PRESS_MASK | GDK_BUTTON_PRESS_MASK   |
 242                                             GDK_BUTTON_RELEASE_MASK |
 243                                             GDK_POINTER_MOTION_MASK  ),
 244                                 NULL, bevent.time);
 245         }
 246
 247         Geom::Point const button_w(bevent.x, bevent.y);
 248
 249         /* Find desktop coordinates */
 250         Geom::Point p = pc->desktop->w2d(button_w);
 251
 252         /* Test whether we hit any anchor. */
 253         SPDrawAnchor *anchor = spdc_test_inside(pc, button_w);
 254
 255         pencil_drag_origin_w = Geom::Point(bevent.x,bevent.y);
 256         pencil_within_tolerance = true;
 257
 258         switch (pc->state) {
 259             case SP_PENCIL_CONTEXT_ADDLINE:
 260                 /* Current segment will be finished with release */
 261                 ret = TRUE;
 262                 break;
 263             default:
 264                 /* Set first point of sequence */
 265                 SnapManager &m = desktop->namedview->snap_manager;
 266                 m.setup(desktop);
 267
 268                 if (bevent.state & GDK_CONTROL_MASK) {
 269                     if (!(bevent.state & GDK_SHIFT_MASK)) {
 270                         m.freeSnapReturnByRef(p, Inkscape::SNAPSOURCE_NODE_HANDLE);
 271                       }
 272                     spdc_create_single_dot(event_context, p, "/tools/freehand/pencil", bevent.state);
 273                     ret = true;
 274                     break;
 275                 }
 276                 if (anchor) {
 277                     p = anchor->dp;
 278                     desktop->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Continuing selected path"));
 279                 } else {
 280
 281                     if (!(bevent.state & GDK_SHIFT_MASK)) {
 282                         // This is the first click of a new curve; deselect item so that
 283                         // this curve is not combined with it (unless it is drawn from its
 284                         // anchor, which is handled by the sibling branch above)
 285                         selection->clear();
 286                         desktop->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Creating new path"));
 287                         m.freeSnapReturnByRef(p, Inkscape::SNAPSOURCE_NODE_HANDLE);
 288                     } else if (selection->singleItem() && SP_IS_PATH(selection->singleItem())) {
 289                         desktop->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Appending to selected path"));
 290                         m.freeSnapReturnByRef(p, Inkscape::SNAPSOURCE_NODE_HANDLE);
 291                     }
 292                 }
 293                 m.unSetup();
 294                 pc->sa = anchor;
 295                 spdc_set_startpoint(pc, p);
 296                 ret = TRUE;
 297                 break;
 298         }
 299
 300         pc->is_drawing = true;
 301     }
 302     return ret;
 303 }
 304
 305 static gint
 306 pencil_handle_motion_notify(SPPencilContext *const pc, GdkEventMotion const &mevent)
 307 {
 308     SPDesktop *const dt = pc->desktop;
 309
 310     if ((mevent.state & GDK_CONTROL_MASK) && (mevent.state & GDK_BUTTON1_MASK)) {
 311         // mouse was accidentally moved during Ctrl+click;
 312         // ignore the motion and create a single point
 313         pc->is_drawing = false;
 314         return TRUE;
 315     }
 316     gint ret = FALSE;
 317
 318     SPEventContext *event_context = SP_EVENT_CONTEXT(pc);
 319     if (event_context->space_panning || mevent.state & GDK_BUTTON2_MASK || mevent.state & GDK_BUTTON3_MASK) {
 320         // allow scrolling
 321         return FALSE;
 322     }
 323
 324     if ( ( mevent.state & GDK_BUTTON1_MASK ) && !pc->grab && pc->is_drawing) {
 325         /* Grab mouse, so release will not pass unnoticed */
 326         pc->grab = SP_CANVAS_ITEM(dt->acetate);
 327         sp_canvas_item_grab(pc->grab, ( GDK_KEY_PRESS_MASK | GDK_BUTTON_PRESS_MASK   |
 328                                         GDK_BUTTON_RELEASE_MASK |
 329                                         GDK_POINTER_MOTION_MASK  ),
 330                             NULL, mevent.time);
 331     }
 332
 333     /* Find desktop coordinates */
 334     Geom::Point p = dt->w2d(Geom::Point(mevent.x, mevent.y));
 335
 336     /* Test whether we hit any anchor. */
 337     SPDrawAnchor *anchor = spdc_test_inside(pc, Geom::Point(mevent.x, mevent.y));
 338
 339     if (pencil_within_tolerance) {
 340         Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 341         gint const tolerance = prefs->getIntLimited("/options/dragtolerance/value", 0, 0, 100);
 342         if ( Geom::LInfty( Geom::Point(mevent.x,mevent.y) - pencil_drag_origin_w ) < tolerance ) {
 343             return FALSE;   // Do not drag if we're within tolerance from origin.
 344         }
 345     }
 346
 347     // Once the user has moved farther than tolerance from the original location
 348     // (indicating they intend to move the object, not click), then always process the
 349     // motion notify coordinates as given (no snapping back to origin)
 350     pencil_within_tolerance = false;
 351
 352     switch (pc->state) {
 353         case SP_PENCIL_CONTEXT_ADDLINE:
 354             /* Set red endpoint */
 355             if (anchor) {
 356                 p = anchor->dp;
 357             } else {
 358                 Geom::Point ptnr(p);
 359                 spdc_endpoint_snap(pc, ptnr, mevent.state);
 360                 p = ptnr;
 361             }
 362             spdc_set_endpoint(pc, p);
 363             ret = TRUE;
 364             break;
 365         default:
 366             /* We may be idle or already freehand */
 367             if ( mevent.state & GDK_BUTTON1_MASK && pc->is_drawing ) {
 368                 if (pc->state == SP_PENCIL_CONTEXT_IDLE) {
 369                     sp_event_context_discard_delayed_snap_event(event_context);
 370                 }
 371                 pc->state = SP_PENCIL_CONTEXT_FREEHAND;
 372
 373                 if ( !pc->sa && !pc->green_anchor ) {
 374                     /* Create green anchor */
 375                     pc->green_anchor = sp_draw_anchor_new(pc, pc->green_curve, TRUE, pc->p[0]);
 376                 }
 377                 if (anchor) {
 378                     p = anchor->dp;
 379                 }
 380
 381                 if ( pc->npoints != 0) { // buttonpress may have happened before we entered draw context!
 382                     if (pc->ps.size() == 0) {
 383                         // Only in freehand mode we have to add the first point also to pc->ps (apparently)
 384                         // - We cannot add this point in spdc_set_startpoint, because we only need it for freehand
 385                         // - We cannot do this in the button press handler because at that point we don't know yet
 386                         //   wheter we're going into freehand mode or not
 387                         pc->ps.push_back(pc->p[0]);
 388                     }
 389                     spdc_add_freehand_point(pc, p, mevent.state);
 390                     ret = TRUE;
 391                 }
 392
 393                 if (anchor && !pc->anchor_statusbar) {
 394                     pc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("<b>Release</b> here to close and finish the path."));
 395                     pc->anchor_statusbar = true;
 396                 } else if (!anchor && pc->anchor_statusbar) {
 397                     pc->_message_context->clear();
 398                     pc->anchor_statusbar = false;
 399                 } else if (!anchor) {
 400                     pc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("Drawing a freehand path"));
 401                 }
 402
 403             } else {
 404                 if (anchor && !pc->anchor_statusbar) {
 405                     pc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("<b>Drag</b> to continue the path from this point."));
 406                     pc->anchor_statusbar = true;
 407                 } else if (!anchor && pc->anchor_statusbar) {
 408                     pc->_message_context->clear();
 409                     pc->anchor_statusbar = false;
 410                 }
 411             }
 412
 413             // Show the pre-snap indicator to communicate to the user where we would snap to if he/she were to
 414             // a) press the mousebutton to start a freehand drawing, or
 415             // b) release the mousebutton to finish a freehand drawing
 416             if (!sp_event_context_knot_mouseover(pc)) {
 417                 SnapManager &m = dt->namedview->snap_manager;
 418                 m.setup(dt);
 419                 m.preSnap(Inkscape::SnapCandidatePoint(p, Inkscape::SNAPSOURCE_NODE_HANDLE));
 420                 m.unSetup();
 421             }
 422             break;
 423     }
 424     return ret;
 425 }
 426
 427 static gint
 428 pencil_handle_button_release(SPPencilContext *const pc, GdkEventButton const &revent)
 429 {
 430     gint ret = FALSE;
 431
 432     SPEventContext *event_context = SP_EVENT_CONTEXT(pc);
 433     if ( revent.button == 1 && pc->is_drawing && !event_context->space_panning) {
 434         SPDesktop *const dt = pc->desktop;
 435
 436         pc->is_drawing = false;
 437
 438         /* Find desktop coordinates */
 439         Geom::Point p = dt->w2d(Geom::Point(revent.x, revent.y));
 440
 441         /* Test whether we hit any anchor. */
 442         SPDrawAnchor *anchor = spdc_test_inside(pc, Geom::Point(revent.x,
 443                                                               revent.y));
 444
 445         switch (pc->state) {
 446             case SP_PENCIL_CONTEXT_IDLE:
 447                 /* Releasing button in idle mode means single click */
 448                 /* We have already set up start point/anchor in button_press */
 449                 if (!(revent.state & GDK_CONTROL_MASK)) {
 450                     // Ctrl+click creates a single point so only set context in ADDLINE mode when Ctrl isn't pressed
 451                     pc->state = SP_PENCIL_CONTEXT_ADDLINE;
 452                 }
 453                 ret = TRUE;
 454                 break;
 455             case SP_PENCIL_CONTEXT_ADDLINE:
 456                 /* Finish segment now */
 457                 if (anchor) {
 458                     p = anchor->dp;
 459                 } else {
 460                     spdc_endpoint_snap(pc, p, revent.state);
 461                 }
 462                 pc->ea = anchor;
 463                 spdc_set_endpoint(pc, p);
 464                 spdc_finish_endpoint(pc);
 465                 pc->state = SP_PENCIL_CONTEXT_IDLE;
 466                 sp_event_context_discard_delayed_snap_event(event_context);
 467                 ret = TRUE;
 468                 break;
 469             case SP_PENCIL_CONTEXT_FREEHAND:
 470                 if (revent.state & GDK_MOD1_MASK) {
 471                     /* sketch mode: interpolate the sketched path and improve the current output path with the new interpolation. don't finish sketch */
 472
 473                     sketch_interpolate(pc);
 474
 475                     if (pc->green_anchor) {
 476                         pc->green_anchor = sp_draw_anchor_destroy(pc->green_anchor);
 477                     }
 478
 479                     pc->state = SP_PENCIL_CONTEXT_SKETCH;
 480                 } else {
 481                     /* Finish segment now */
 482                     /// \todo fixme: Clean up what follows (Lauris)
 483                     if (anchor) {
 484                         p = anchor->dp;
 485                     } else {
 486                         Geom::Point p_end = p;
 487                         spdc_endpoint_snap(pc, p_end, revent.state);
 488                         if (p_end != p) {
 489                             // then we must have snapped!
 490                             spdc_add_freehand_point(pc, p_end, revent.state);
 491                         }
 492                     }
 493
 494                     pc->ea = anchor;
 495                     /* Write curves to object */
 496
 497                     dt->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Finishing freehand"));
 498
 499                     interpolate(pc);
 500                     spdc_concat_colors_and_flush(pc, FALSE);
 501                     pc->sa = NULL;
 502                     pc->ea = NULL;
 503                     if (pc->green_anchor) {
 504                         pc->green_anchor = sp_draw_anchor_destroy(pc->green_anchor);
 505                     }
 506                     pc->state = SP_PENCIL_CONTEXT_IDLE;
 507                     // reset sketch mode too
 508                     pc->sketch_n = 0;
 509                 }
 510                 ret = TRUE;
 511                 break;
 512             case SP_PENCIL_CONTEXT_SKETCH:
 513             default:
 514                 break;
 515         }
 516
 517         if (pc->grab) {
 518             /* Release grab now */
 519             sp_canvas_item_ungrab(pc->grab, revent.time);
 520             pc->grab = NULL;
 521         }
 522
 523         ret = TRUE;
 524     }
 525     return ret;
 526 }
 527
 528 static void
 529 pencil_cancel (SPPencilContext *const pc)
 530 {
 531     if (pc->grab) {
 532         /* Release grab now */
 533         sp_canvas_item_ungrab(pc->grab, 0);
 534         pc->grab = NULL;
 535     }
 536
 537     pc->is_drawing = false;
 538     pc->state = SP_PENCIL_CONTEXT_IDLE;
 539     sp_event_context_discard_delayed_snap_event(SP_EVENT_CONTEXT(pc));
 540
 541     pc->red_curve->reset();
 542     sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), NULL);
 543     while (pc->green_bpaths) {
 544         gtk_object_destroy(GTK_OBJECT(pc->green_bpaths->data));
 545         pc->green_bpaths = g_slist_remove(pc->green_bpaths, pc->green_bpaths->data);
 546     }
 547     pc->green_curve->reset();
 548     if (pc->green_anchor) {
 549         pc->green_anchor = sp_draw_anchor_destroy(pc->green_anchor);
 550     }
 551
 552     pc->_message_context->clear();
 553     pc->_message_context->flash(Inkscape::NORMAL_MESSAGE, _("Drawing cancelled"));
 554
 555     sp_canvas_end_forced_full_redraws(pc->desktop->canvas);
 556 }
 557
 558 static gint
 559 pencil_handle_key_press(SPPencilContext *const pc, guint const keyval, guint const state)
 560 {
 561     gint ret = FALSE;
 562     switch (keyval) {
 563         case GDK_Up:
 564         case GDK_Down:
 565         case GDK_KP_Up:
 566         case GDK_KP_Down:
 567             // Prevent the zoom field from activation.
 568             if (!mod_ctrl_only(state)) {
 569                 ret = TRUE;
 570             }
 571             break;
 572         case GDK_Escape:
 573             if (pc->npoints != 0) {
 574                 // if drawing, cancel, otherwise pass it up for deselecting
 575                 if (pc->state != SP_PENCIL_CONTEXT_IDLE) {
 576                     pencil_cancel (pc);
 577                     ret = TRUE;
 578                 }
 579             }
 580             break;
 581         case GDK_z:
 582         case GDK_Z:
 583             if (mod_ctrl_only(state) && pc->npoints != 0) {
 584                 // if drawing, cancel, otherwise pass it up for undo
 585                 if (pc->state != SP_PENCIL_CONTEXT_IDLE) {
 586                     pencil_cancel (pc);
 587                     ret = TRUE;
 588                 }
 589             }
 590             break;
 591         case GDK_g:
 592         case GDK_G:
 593             if (mod_shift_only(state)) {
 594                 sp_selection_to_guides(SP_EVENT_CONTEXT(pc)->desktop);
 595                 ret = true;
 596             }
 597             break;
 598         case GDK_Alt_L:
 599         case GDK_Alt_R:
 600         case GDK_Meta_L:
 601         case GDK_Meta_R:
 602             if (pc->state == SP_PENCIL_CONTEXT_IDLE) {
 603                 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."));
 604             }
 605             break;
 606         default:
 607             break;
 608     }
 609     return ret;
 610 }
 611
 612 static gint
 613 pencil_handle_key_release(SPPencilContext *const pc, guint const keyval, guint const /*state*/)
 614 {
 615     gint ret = FALSE;
 616     switch (keyval) {
 617         case GDK_Alt_L:
 618         case GDK_Alt_R:
 619         case GDK_Meta_L:
 620         case GDK_Meta_R:
 621             if (pc->state == SP_PENCIL_CONTEXT_SKETCH) {
 622                 spdc_concat_colors_and_flush(pc, FALSE);
 623                 pc->sketch_n = 0;
 624                 pc->sa = NULL;
 625                 pc->ea = NULL;
 626                 if (pc->green_anchor) {
 627                     pc->green_anchor = sp_draw_anchor_destroy(pc->green_anchor);
 628                 }
 629                 pc->state = SP_PENCIL_CONTEXT_IDLE;
 630                 sp_event_context_discard_delayed_snap_event(SP_EVENT_CONTEXT(pc));
 631                 pc->desktop->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Finishing freehand sketch"));
 632                 ret = TRUE;
 633             }
 634             break;
 635         default:
 636             break;
 637     }
 638     return ret;
 639 }
 640
 641 /**
 642  * Reset points and set new starting point.
 643  */
 644 static void
 645 spdc_set_startpoint(SPPencilContext *const pc, Geom::Point const p)
 646 {
 647     pc->npoints = 0;
 648     pc->red_curve_is_valid = false;
 649     if (in_svg_plane(p)) {
 650         pc->p[pc->npoints++] = p;
 651     }
 652 }
 653
 654 /**
 655  * Change moving endpoint position.
 656  * <ul>
 657  * <li>Ctrl constrains to moving to H/V direction, snapping in given direction.
 658  * <li>Otherwise we snap freely to whatever attractors are available.
 659  * </ul>
 660  *
 661  * Number of points is (re)set to 2 always, 2nd point is modified.
 662  * We change RED curve.
 663  */
 664 static void
 665 spdc_set_endpoint(SPPencilContext *const pc, Geom::Point const p)
 666 {
 667     if (pc->npoints == 0) {
 668         return;
 669         /* May occur if first point wasn't in SVG plane (e.g. weird w2d transform, perhaps from bad
 670          * zoom setting).
 671          */
 672     }
 673     g_return_if_fail( pc->npoints > 0 );
 674
 675     pc->red_curve->reset();
 676     if ( ( p == pc->p[0] )
 677          || !in_svg_plane(p) )
 678     {
 679         pc->npoints = 1;
 680     } else {
 681         pc->p[1] = p;
 682         pc->npoints = 2;
 683
 684         pc->red_curve->moveto(pc->p[0]);
 685         pc->red_curve->lineto(pc->p[1]);
 686         pc->red_curve_is_valid = true;
 687
 688         sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), pc->red_curve);
 689     }
 690 }
 691
 692 /**
 693  * Finalize addline.
 694  *
 695  * \todo
 696  * fixme: I'd like remove red reset from concat colors (lauris).
 697  * Still not sure, how it will make most sense.
 698  */
 699 static void
 700 spdc_finish_endpoint(SPPencilContext *const pc)
 701 {
 702     if ( ( pc->red_curve->is_empty() )
 703          || ( *(pc->red_curve->first_point()) == *(pc->red_curve->second_point())   ) )
 704     {
 705         pc->red_curve->reset();
 706         sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), NULL);
 707     } else {
 708         /* Write curves to object. */
 709         spdc_concat_colors_and_flush(pc, FALSE);
 710         pc->sa = NULL;
 711         pc->ea = NULL;
 712     }
 713 }
 714
 715
 716 static void
 717 spdc_add_freehand_point(SPPencilContext *pc, Geom::Point p, guint /*state*/)
 718 {
 719     g_assert( pc->npoints > 0 );
 720     g_return_if_fail(unsigned(pc->npoints) < G_N_ELEMENTS(pc->p));
 721
 722     if ( ( p != pc->p[ pc->npoints - 1 ] )
 723          && in_svg_plane(p) )
 724     {
 725         pc->ps.push_back(p);
 726         pc->p[pc->npoints++] = p;
 727         fit_and_split(pc);
 728     }
 729 }
 730
 731 static inline double
 732 square(double const x)
 733 {
 734     return x * x;
 735 }
 736
 737 static void
 738 interpolate(SPPencilContext *pc)
 739 {
 740     if ( pc->ps.size() <= 1 ) {
 741         return;
 742     }
 743
 744     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 745     double const tol = prefs->getDoubleLimited("/tools/freehand/pencil/tolerance", 10.0, 1.0, 100.0) * 0.4;
 746     double const tolerance_sq = 0.02 * square( pc->desktop->w2d().descrim() *
 747                                                tol) * exp(0.2*tol - 2);
 748
 749     g_assert(is_zero(pc->req_tangent)
 750              || is_unit_vector(pc->req_tangent));
 751     Geom::Point const tHatEnd(0, 0);
 752
 753     guint n_points  = pc->ps.size();
 754     pc->green_curve->reset();
 755     pc->red_curve->reset();
 756     pc->red_curve_is_valid = false;
 757
 758     Geom::Point * b = g_new(Geom::Point, 4*n_points);
 759     Geom::Point * points = g_new(Geom::Point, 4*n_points);
 760     for (unsigned int i = 0; i < pc->ps.size(); i++) {
 761         points[i] = pc->ps[i];
 762     }
 763
 764     // worst case gives us a segment per point
 765     int max_segs = 4*n_points;
 766
 767     int const n_segs = Geom::bezier_fit_cubic_r(b, points, n_points,
 768                                              tolerance_sq, max_segs);
 769
 770     if ( n_segs > 0)
 771     {
 772         /* Fit and draw and reset state */
 773         pc->green_curve->moveto(b[0]);
 774         for (int c = 0; c < n_segs; c++) {
 775             pc->green_curve->curveto(b[4*c+1], b[4*c+2], b[4*c+3]);
 776         }
 777         sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), pc->green_curve);
 778
 779         /* Fit and draw and copy last point */
 780         g_assert(!pc->green_curve->is_empty());
 781
 782         /* Set up direction of next curve. */
 783         {
 784             Geom::CubicBezier const * last_seg = dynamic_cast<Geom::CubicBezier const *>(pc->green_curve->last_segment());
 785             g_assert( last_seg );      // Relevance: validity of (*last_seg)[2]
 786             pc->p[0] = last_seg->finalPoint();
 787             pc->npoints = 1;
 788             Geom::Point const req_vec( pc->p[0] - (*last_seg)[2] );
 789             pc->req_tangent = ( ( Geom::is_zero(req_vec) || !in_svg_plane(req_vec) )
 790                                 ? Geom::Point(0, 0)
 791                                 : Geom::unit_vector(req_vec) );
 792         }
 793     }
 794     g_free(b);
 795     g_free(points);
 796     pc->ps.clear();
 797 }
 798
 799
 800 /* interpolates the sketched curve and tweaks the current sketch interpolation*/
 801 static void
 802 sketch_interpolate(SPPencilContext *pc)
 803 {
 804     if ( pc->ps.size() <= 1 ) {
 805         return;
 806     }
 807
 808     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 809     double const tol = prefs->getDoubleLimited("/tools/freehand/pencil/tolerance", 10.0, 1.0, 100.0) * 0.4;
 810     double const tolerance_sq = 0.02 * square( pc->desktop->w2d().descrim() *
 811                                                tol) * exp(0.2*tol - 2);
 812
 813     bool average_all_sketches = prefs->getBool("/tools/freehand/pencil/average_all_sketches", true);
 814
 815     g_assert(is_zero(pc->req_tangent)
 816              || is_unit_vector(pc->req_tangent));
 817     Geom::Point const tHatEnd(0, 0);
 818
 819     guint n_points  = pc->ps.size();
 820     pc->red_curve->reset();
 821     pc->red_curve_is_valid = false;
 822
 823     Geom::Point * b = g_new(Geom::Point, 4*n_points);
 824     Geom::Point * points = g_new(Geom::Point, 4*n_points);
 825     for (unsigned i = 0; i < pc->ps.size(); i++) {
 826         points[i] = pc->ps[i];
 827     }
 828
 829     // worst case gives us a segment per point
 830     int max_segs = 4*n_points;
 831
 832     int const n_segs = Geom::bezier_fit_cubic_r(b, points, n_points,
 833                                              tolerance_sq, max_segs);
 834
 835     if ( n_segs > 0)
 836     {
 837         Geom::Path fit(b[0]);
 838         for (int c = 0; c < n_segs; c++) {
 839             fit.appendNew<Geom::CubicBezier>(b[4*c+1], b[4*c+2], b[4*c+3]);
 840         }
 841         Geom::Piecewise<Geom::D2<Geom::SBasis> > fit_pwd2 = fit.toPwSb();
 842
 843         double t =0.;
 844         if ( pc->sketch_n > 0 ) {
 845             if (average_all_sketches) {
 846                 // Average = (sum of all) / n
 847                 //         = (sum of all + new one) / n+1
 848                 //         = ((old average)*n + new one) / n+1
 849                 t = pc->sketch_n / (pc->sketch_n + 1.);
 850             } else {
 851                 t = 0.5;
 852             }
 853             pc->sketch_interpolation = Geom::lerp(t, fit_pwd2, pc->sketch_interpolation);
 854             // simplify path, to eliminate small segments
 855             Path *path = new Path;
 856             path->LoadPathVector(Geom::path_from_piecewise(pc->sketch_interpolation, 0.01));
 857             path->Simplify(0.5);
 858             Geom::PathVector *pathv = path->MakePathVector();
 859             pc->sketch_interpolation = (*pathv)[0].toPwSb();
 860             delete path;
 861             delete pathv;
 862         } else {
 863             pc->sketch_interpolation = fit_pwd2;
 864         }
 865         pc->sketch_n++;
 866
 867         pc->green_curve->reset();
 868         pc->green_curve->set_pathvector(Geom::path_from_piecewise(pc->sketch_interpolation, 0.01));
 869         sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), pc->green_curve);
 870
 871         /* Fit and draw and copy last point */
 872         g_assert(!pc->green_curve->is_empty());
 873
 874         /* Set up direction of next curve. */
 875         {
 876             Geom::CubicBezier const * last_seg = dynamic_cast<Geom::CubicBezier const *>(pc->green_curve->last_segment());
 877             g_assert( last_seg );      // Relevance: validity of (*last_seg)[2]
 878             pc->p[0] = last_seg->finalPoint();
 879             pc->npoints = 1;
 880             Geom::Point const req_vec( pc->p[0] - (*last_seg)[2] );
 881             pc->req_tangent = ( ( Geom::is_zero(req_vec) || !in_svg_plane(req_vec) )
 882                                 ? Geom::Point(0, 0)
 883                                 : Geom::unit_vector(req_vec) );
 884         }
 885     }
 886     g_free(b);
 887     g_free(points);
 888     pc->ps.clear();
 889 }
 890
 891 static void
 892 fit_and_split(SPPencilContext *pc)
 893 {
 894     g_assert( pc->npoints > 1 );
 895
 896     double const tolerance_sq = 0;
 897
 898     Geom::Point b[4];
 899     g_assert(is_zero(pc->req_tangent)
 900              || is_unit_vector(pc->req_tangent));
 901     Geom::Point const tHatEnd(0, 0);
 902     int const n_segs = Geom::bezier_fit_cubic_full(b, NULL, pc->p, pc->npoints,
 903                                                 pc->req_tangent, tHatEnd,
 904                                                 tolerance_sq, 1);
 905     if ( n_segs > 0
 906          && unsigned(pc->npoints) < G_N_ELEMENTS(pc->p) )
 907     {
 908         /* Fit and draw and reset state */
 909         pc->red_curve->reset();
 910         pc->red_curve->moveto(b[0]);
 911         pc->red_curve->curveto(b[1], b[2], b[3]);
 912         sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), pc->red_curve);
 913         pc->red_curve_is_valid = true;
 914     } else {
 915         /* Fit and draw and copy last point */
 916
 917         g_assert(!pc->red_curve->is_empty());
 918
 919         /* Set up direction of next curve. */
 920         {
 921             Geom::CubicBezier const * last_seg = dynamic_cast<Geom::CubicBezier const *>(pc->red_curve->last_segment());
 922             g_assert( last_seg );      // Relevance: validity of (*last_seg)[2]
 923             pc->p[0] = last_seg->finalPoint();
 924             pc->npoints = 1;
 925             Geom::Point const req_vec( pc->p[0] - (*last_seg)[2] );
 926             pc->req_tangent = ( ( Geom::is_zero(req_vec) || !in_svg_plane(req_vec) )
 927                                 ? Geom::Point(0, 0)
 928                                 : Geom::unit_vector(req_vec) );
 929         }
 930
 931         pc->green_curve->append_continuous(pc->red_curve, 0.0625);
 932         SPCurve *curve = pc->red_curve->copy();
 933
 934         /// \todo fixme:
 935         SPCanvasItem *cshape = sp_canvas_bpath_new(sp_desktop_sketch(pc->desktop), curve);
 936         curve->unref();
 937         sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(cshape), pc->green_color, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 938
 939         pc->green_bpaths = g_slist_prepend(pc->green_bpaths, cshape);
 940
 941         pc->red_curve_is_valid = false;
 942     }
 943 }
 944
 945
 946 /*
 947   Local Variables:
 948   mode:c++
 949   c-file-style:"stroustrup"
 950   c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
 951   indent-tabs-mode:nil
 952   fill-column:99
 953   End:
 954 */
 955 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :