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
 267                 if (bevent.state & GDK_CONTROL_MASK) {
 268                     m.setup(desktop);
 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                     m.unSetup();
 274                     ret = true;
 275                     break;
 276                 }
 277                 if (anchor) {
 278                     p = anchor->dp;
 279                     desktop->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Continuing selected path"));
 280                 } else {
 281                     m.setup(desktop);
 282                     if (!(bevent.state & GDK_SHIFT_MASK)) {
 283                         // This is the first click of a new curve; deselect item so that
 284                         // this curve is not combined with it (unless it is drawn from its
 285                         // anchor, which is handled by the sibling branch above)
 286                         selection->clear();
 287                         desktop->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Creating new path"));
 288                         m.freeSnapReturnByRef(p, Inkscape::SNAPSOURCE_NODE_HANDLE);
 289                     } else if (selection->singleItem() && SP_IS_PATH(selection->singleItem())) {
 290                         desktop->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Appending to selected path"));
 291                         m.freeSnapReturnByRef(p, Inkscape::SNAPSOURCE_NODE_HANDLE);
 292                     }
 293                     m.unSetup();
 294                 }
 295                 pc->sa = anchor;
 296                 spdc_set_startpoint(pc, p);
 297                 ret = TRUE;
 298                 break;
 299         }
 300
 301         pc->is_drawing = true;
 302     }
 303     return ret;
 304 }
 305
 306 static gint
 307 pencil_handle_motion_notify(SPPencilContext *const pc, GdkEventMotion const &mevent)
 308 {
 309     SPDesktop *const dt = pc->desktop;
 310
 311     if ((mevent.state & GDK_CONTROL_MASK) && (mevent.state & GDK_BUTTON1_MASK)) {
 312         // mouse was accidentally moved during Ctrl+click;
 313         // ignore the motion and create a single point
 314         pc->is_drawing = false;
 315         return TRUE;
 316     }
 317     gint ret = FALSE;
 318
 319     SPEventContext *event_context = SP_EVENT_CONTEXT(pc);
 320     if (event_context->space_panning || mevent.state & GDK_BUTTON2_MASK || mevent.state & GDK_BUTTON3_MASK) {
 321         // allow scrolling
 322         return FALSE;
 323     }
 324
 325     if ( ( mevent.state & GDK_BUTTON1_MASK ) && !pc->grab && pc->is_drawing) {
 326         /* Grab mouse, so release will not pass unnoticed */
 327         pc->grab = SP_CANVAS_ITEM(dt->acetate);
 328         sp_canvas_item_grab(pc->grab, ( GDK_KEY_PRESS_MASK | GDK_BUTTON_PRESS_MASK   |
 329                                         GDK_BUTTON_RELEASE_MASK |
 330                                         GDK_POINTER_MOTION_MASK  ),
 331                             NULL, mevent.time);
 332     }
 333
 334     /* Find desktop coordinates */
 335     Geom::Point p = dt->w2d(Geom::Point(mevent.x, mevent.y));
 336
 337     /* Test whether we hit any anchor. */
 338     SPDrawAnchor *anchor = spdc_test_inside(pc, Geom::Point(mevent.x, mevent.y));
 339
 340     if (pencil_within_tolerance) {
 341         Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 342         gint const tolerance = prefs->getIntLimited("/options/dragtolerance/value", 0, 0, 100);
 343         if ( Geom::LInfty( Geom::Point(mevent.x,mevent.y) - pencil_drag_origin_w ) < tolerance ) {
 344             return FALSE;   // Do not drag if we're within tolerance from origin.
 345         }
 346     }
 347
 348     // Once the user has moved farther than tolerance from the original location
 349     // (indicating they intend to move the object, not click), then always process the
 350     // motion notify coordinates as given (no snapping back to origin)
 351     pencil_within_tolerance = false;
 352
 353     switch (pc->state) {
 354         case SP_PENCIL_CONTEXT_ADDLINE:
 355             /* Set red endpoint */
 356             if (anchor) {
 357                 p = anchor->dp;
 358             } else {
 359                 Geom::Point ptnr(p);
 360                 spdc_endpoint_snap(pc, ptnr, mevent.state);
 361                 p = ptnr;
 362             }
 363             spdc_set_endpoint(pc, p);
 364             ret = TRUE;
 365             break;
 366         default:
 367             /* We may be idle or already freehand */
 368             if ( mevent.state & GDK_BUTTON1_MASK && pc->is_drawing ) {
 369                 if (pc->state == SP_PENCIL_CONTEXT_IDLE) {
 370                     sp_event_context_discard_delayed_snap_event(event_context);
 371                 }
 372                 pc->state = SP_PENCIL_CONTEXT_FREEHAND;
 373
 374                 if ( !pc->sa && !pc->green_anchor ) {
 375                     /* Create green anchor */
 376                     pc->green_anchor = sp_draw_anchor_new(pc, pc->green_curve, TRUE, pc->p[0]);
 377                 }
 378                 if (anchor) {
 379                     p = anchor->dp;
 380                 }
 381
 382                 if ( pc->npoints != 0) { // buttonpress may have happened before we entered draw context!
 383                     if (pc->ps.size() == 0) {
 384                         // Only in freehand mode we have to add the first point also to pc->ps (apparently)
 385                         // - We cannot add this point in spdc_set_startpoint, because we only need it for freehand
 386                         // - We cannot do this in the button press handler because at that point we don't know yet
 387                         //   wheter we're going into freehand mode or not
 388                         pc->ps.push_back(pc->p[0]);
 389                     }
 390                     spdc_add_freehand_point(pc, p, mevent.state);
 391                     ret = TRUE;
 392                 }
 393
 394                 if (anchor && !pc->anchor_statusbar) {
 395                     pc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("<b>Release</b> here to close and finish the path."));
 396                     pc->anchor_statusbar = true;
 397                 } else if (!anchor && pc->anchor_statusbar) {
 398                     pc->_message_context->clear();
 399                     pc->anchor_statusbar = false;
 400                 } else if (!anchor) {
 401                     pc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("Drawing a freehand path"));
 402                 }
 403
 404             } else {
 405                 if (anchor && !pc->anchor_statusbar) {
 406                     pc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("<b>Drag</b> to continue the path from this point."));
 407                     pc->anchor_statusbar = true;
 408                 } else if (!anchor && pc->anchor_statusbar) {
 409                     pc->_message_context->clear();
 410                     pc->anchor_statusbar = false;
 411                 }
 412             }
 413
 414             // Show the pre-snap indicator to communicate to the user where we would snap to if he/she were to
 415             // a) press the mousebutton to start a freehand drawing, or
 416             // b) release the mousebutton to finish a freehand drawing
 417             if (!sp_event_context_knot_mouseover(pc)) {
 418                 SnapManager &m = dt->namedview->snap_manager;
 419                 m.setup(dt);
 420                 m.preSnap(Inkscape::SnapCandidatePoint(p, Inkscape::SNAPSOURCE_NODE_HANDLE));
 421                 m.unSetup();
 422             }
 423             break;
 424     }
 425     return ret;
 426 }
 427
 428 static gint
 429 pencil_handle_button_release(SPPencilContext *const pc, GdkEventButton const &revent)
 430 {
 431     gint ret = FALSE;
 432
 433     SPEventContext *event_context = SP_EVENT_CONTEXT(pc);
 434     if ( revent.button == 1 && pc->is_drawing && !event_context->space_panning) {
 435         SPDesktop *const dt = pc->desktop;
 436
 437         pc->is_drawing = false;
 438
 439         /* Find desktop coordinates */
 440         Geom::Point p = dt->w2d(Geom::Point(revent.x, revent.y));
 441
 442         /* Test whether we hit any anchor. */
 443         SPDrawAnchor *anchor = spdc_test_inside(pc, Geom::Point(revent.x,
 444                                                               revent.y));
 445
 446         switch (pc->state) {
 447             case SP_PENCIL_CONTEXT_IDLE:
 448                 /* Releasing button in idle mode means single click */
 449                 /* We have already set up start point/anchor in button_press */
 450                 if (!(revent.state & GDK_CONTROL_MASK)) {
 451                     // Ctrl+click creates a single point so only set context in ADDLINE mode when Ctrl isn't pressed
 452                     pc->state = SP_PENCIL_CONTEXT_ADDLINE;
 453                 }
 454                 ret = TRUE;
 455                 break;
 456             case SP_PENCIL_CONTEXT_ADDLINE:
 457                 /* Finish segment now */
 458                 if (anchor) {
 459                     p = anchor->dp;
 460                 } else {
 461                     spdc_endpoint_snap(pc, p, revent.state);
 462                 }
 463                 pc->ea = anchor;
 464                 spdc_set_endpoint(pc, p);
 465                 spdc_finish_endpoint(pc);
 466                 pc->state = SP_PENCIL_CONTEXT_IDLE;
 467                 sp_event_context_discard_delayed_snap_event(event_context);
 468                 ret = TRUE;
 469                 break;
 470             case SP_PENCIL_CONTEXT_FREEHAND:
 471                 if (revent.state & GDK_MOD1_MASK) {
 472                     /* sketch mode: interpolate the sketched path and improve the current output path with the new interpolation. don't finish sketch */
 473
 474                     sketch_interpolate(pc);
 475
 476                     if (pc->green_anchor) {
 477                         pc->green_anchor = sp_draw_anchor_destroy(pc->green_anchor);
 478                     }
 479
 480                     pc->state = SP_PENCIL_CONTEXT_SKETCH;
 481                 } else {
 482                     /* Finish segment now */
 483                     /// \todo fixme: Clean up what follows (Lauris)
 484                     if (anchor) {
 485                         p = anchor->dp;
 486                     } else {
 487                         Geom::Point p_end = p;
 488                         spdc_endpoint_snap(pc, p_end, revent.state);
 489                         if (p_end != p) {
 490                             // then we must have snapped!
 491                             spdc_add_freehand_point(pc, p_end, revent.state);
 492                         }
 493                     }
 494
 495                     pc->ea = anchor;
 496                     /* Write curves to object */
 497
 498                     dt->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Finishing freehand"));
 499
 500                     interpolate(pc);
 501                     spdc_concat_colors_and_flush(pc, FALSE);
 502                     pc->sa = NULL;
 503                     pc->ea = NULL;
 504                     if (pc->green_anchor) {
 505                         pc->green_anchor = sp_draw_anchor_destroy(pc->green_anchor);
 506                     }
 507                     pc->state = SP_PENCIL_CONTEXT_IDLE;
 508                     // reset sketch mode too
 509                     pc->sketch_n = 0;
 510                 }
 511                 ret = TRUE;
 512                 break;
 513             case SP_PENCIL_CONTEXT_SKETCH:
 514             default:
 515                 break;
 516         }
 517
 518         if (pc->grab) {
 519             /* Release grab now */
 520             sp_canvas_item_ungrab(pc->grab, revent.time);
 521             pc->grab = NULL;
 522         }
 523
 524         ret = TRUE;
 525     }
 526     return ret;
 527 }
 528
 529 static void
 530 pencil_cancel (SPPencilContext *const pc)
 531 {
 532     if (pc->grab) {
 533         /* Release grab now */
 534         sp_canvas_item_ungrab(pc->grab, 0);
 535         pc->grab = NULL;
 536     }
 537
 538     pc->is_drawing = false;
 539     pc->state = SP_PENCIL_CONTEXT_IDLE;
 540     sp_event_context_discard_delayed_snap_event(SP_EVENT_CONTEXT(pc));
 541
 542     pc->red_curve->reset();
 543     sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), NULL);
 544     while (pc->green_bpaths) {
 545         gtk_object_destroy(GTK_OBJECT(pc->green_bpaths->data));
 546         pc->green_bpaths = g_slist_remove(pc->green_bpaths, pc->green_bpaths->data);
 547     }
 548     pc->green_curve->reset();
 549     if (pc->green_anchor) {
 550         pc->green_anchor = sp_draw_anchor_destroy(pc->green_anchor);
 551     }
 552
 553     pc->_message_context->clear();
 554     pc->_message_context->flash(Inkscape::NORMAL_MESSAGE, _("Drawing cancelled"));
 555
 556     sp_canvas_end_forced_full_redraws(pc->desktop->canvas);
 557 }
 558
 559 static gint
 560 pencil_handle_key_press(SPPencilContext *const pc, guint const keyval, guint const state)
 561 {
 562     gint ret = FALSE;
 563     switch (keyval) {
 564         case GDK_Up:
 565         case GDK_Down:
 566         case GDK_KP_Up:
 567         case GDK_KP_Down:
 568             // Prevent the zoom field from activation.
 569             if (!mod_ctrl_only(state)) {
 570                 ret = TRUE;
 571             }
 572             break;
 573         case GDK_Escape:
 574             if (pc->npoints != 0) {
 575                 // if drawing, cancel, otherwise pass it up for deselecting
 576                 if (pc->state != SP_PENCIL_CONTEXT_IDLE) {
 577                     pencil_cancel (pc);
 578                     ret = TRUE;
 579                 }
 580             }
 581             break;
 582         case GDK_z:
 583         case GDK_Z:
 584             if (mod_ctrl_only(state) && pc->npoints != 0) {
 585                 // if drawing, cancel, otherwise pass it up for undo
 586                 if (pc->state != SP_PENCIL_CONTEXT_IDLE) {
 587                     pencil_cancel (pc);
 588                     ret = TRUE;
 589                 }
 590             }
 591             break;
 592         case GDK_g:
 593         case GDK_G:
 594             if (mod_shift_only(state)) {
 595                 sp_selection_to_guides(SP_EVENT_CONTEXT(pc)->desktop);
 596                 ret = true;
 597             }
 598             break;
 599         case GDK_Alt_L:
 600         case GDK_Alt_R:
 601         case GDK_Meta_L:
 602         case GDK_Meta_R:
 603             if (pc->state == SP_PENCIL_CONTEXT_IDLE) {
 604                 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."));
 605             }
 606             break;
 607         default:
 608             break;
 609     }
 610     return ret;
 611 }
 612
 613 static gint
 614 pencil_handle_key_release(SPPencilContext *const pc, guint const keyval, guint const /*state*/)
 615 {
 616     gint ret = FALSE;
 617     switch (keyval) {
 618         case GDK_Alt_L:
 619         case GDK_Alt_R:
 620         case GDK_Meta_L:
 621         case GDK_Meta_R:
 622             if (pc->state == SP_PENCIL_CONTEXT_SKETCH) {
 623                 spdc_concat_colors_and_flush(pc, FALSE);
 624                 pc->sketch_n = 0;
 625                 pc->sa = NULL;
 626                 pc->ea = NULL;
 627                 if (pc->green_anchor) {
 628                     pc->green_anchor = sp_draw_anchor_destroy(pc->green_anchor);
 629                 }
 630                 pc->state = SP_PENCIL_CONTEXT_IDLE;
 631                 sp_event_context_discard_delayed_snap_event(SP_EVENT_CONTEXT(pc));
 632                 pc->desktop->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Finishing freehand sketch"));
 633                 ret = TRUE;
 634             }
 635             break;
 636         default:
 637             break;
 638     }
 639     return ret;
 640 }
 641
 642 /**
 643  * Reset points and set new starting point.
 644  */
 645 static void
 646 spdc_set_startpoint(SPPencilContext *const pc, Geom::Point const p)
 647 {
 648     pc->npoints = 0;
 649     pc->red_curve_is_valid = false;
 650     if (in_svg_plane(p)) {
 651         pc->p[pc->npoints++] = p;
 652     }
 653 }
 654
 655 /**
 656  * Change moving endpoint position.
 657  * <ul>
 658  * <li>Ctrl constrains to moving to H/V direction, snapping in given direction.
 659  * <li>Otherwise we snap freely to whatever attractors are available.
 660  * </ul>
 661  *
 662  * Number of points is (re)set to 2 always, 2nd point is modified.
 663  * We change RED curve.
 664  */
 665 static void
 666 spdc_set_endpoint(SPPencilContext *const pc, Geom::Point const p)
 667 {
 668     if (pc->npoints == 0) {
 669         return;
 670         /* May occur if first point wasn't in SVG plane (e.g. weird w2d transform, perhaps from bad
 671          * zoom setting).
 672          */
 673     }
 674     g_return_if_fail( pc->npoints > 0 );
 675
 676     pc->red_curve->reset();
 677     if ( ( p == pc->p[0] )
 678          || !in_svg_plane(p) )
 679     {
 680         pc->npoints = 1;
 681     } else {
 682         pc->p[1] = p;
 683         pc->npoints = 2;
 684
 685         pc->red_curve->moveto(pc->p[0]);
 686         pc->red_curve->lineto(pc->p[1]);
 687         pc->red_curve_is_valid = true;
 688
 689         sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), pc->red_curve);
 690     }
 691 }
 692
 693 /**
 694  * Finalize addline.
 695  *
 696  * \todo
 697  * fixme: I'd like remove red reset from concat colors (lauris).
 698  * Still not sure, how it will make most sense.
 699  */
 700 static void
 701 spdc_finish_endpoint(SPPencilContext *const pc)
 702 {
 703     if ( ( pc->red_curve->is_empty() )
 704          || ( *(pc->red_curve->first_point()) == *(pc->red_curve->second_point())   ) )
 705     {
 706         pc->red_curve->reset();
 707         sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), NULL);
 708     } else {
 709         /* Write curves to object. */
 710         spdc_concat_colors_and_flush(pc, FALSE);
 711         pc->sa = NULL;
 712         pc->ea = NULL;
 713     }
 714 }
 715
 716
 717 static void
 718 spdc_add_freehand_point(SPPencilContext *pc, Geom::Point p, guint /*state*/)
 719 {
 720     g_assert( pc->npoints > 0 );
 721     g_return_if_fail(unsigned(pc->npoints) < G_N_ELEMENTS(pc->p));
 722
 723     if ( ( p != pc->p[ pc->npoints - 1 ] )
 724          && in_svg_plane(p) )
 725     {
 726         pc->ps.push_back(p);
 727         pc->p[pc->npoints++] = p;
 728         fit_and_split(pc);
 729     }
 730 }
 731
 732 static inline double
 733 square(double const x)
 734 {
 735     return x * x;
 736 }
 737
 738 static void
 739 interpolate(SPPencilContext *pc)
 740 {
 741     if ( pc->ps.size() <= 1 ) {
 742         return;
 743     }
 744
 745     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 746     double const tol = prefs->getDoubleLimited("/tools/freehand/pencil/tolerance", 10.0, 1.0, 100.0) * 0.4;
 747     double const tolerance_sq = 0.02 * square( pc->desktop->w2d().descrim() *
 748                                                tol) * exp(0.2*tol - 2);
 749
 750     g_assert(is_zero(pc->req_tangent)
 751              || is_unit_vector(pc->req_tangent));
 752     Geom::Point const tHatEnd(0, 0);
 753
 754     guint n_points  = pc->ps.size();
 755     pc->green_curve->reset();
 756     pc->red_curve->reset();
 757     pc->red_curve_is_valid = false;
 758
 759     Geom::Point * b = g_new(Geom::Point, 4*n_points);
 760     Geom::Point * points = g_new(Geom::Point, 4*n_points);
 761     for (unsigned int i = 0; i < pc->ps.size(); i++) {
 762         points[i] = pc->ps[i];
 763     }
 764
 765     // worst case gives us a segment per point
 766     int max_segs = 4*n_points;
 767
 768     int const n_segs = Geom::bezier_fit_cubic_r(b, points, n_points,
 769                                              tolerance_sq, max_segs);
 770
 771     if ( n_segs > 0)
 772     {
 773         /* Fit and draw and reset state */
 774         pc->green_curve->moveto(b[0]);
 775         for (int c = 0; c < n_segs; c++) {
 776             pc->green_curve->curveto(b[4*c+1], b[4*c+2], b[4*c+3]);
 777         }
 778         sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), pc->green_curve);
 779
 780         /* Fit and draw and copy last point */
 781         g_assert(!pc->green_curve->is_empty());
 782
 783         /* Set up direction of next curve. */
 784         {
 785             Geom::CubicBezier const * last_seg = dynamic_cast<Geom::CubicBezier const *>(pc->green_curve->last_segment());
 786             g_assert( last_seg );      // Relevance: validity of (*last_seg)[2]
 787             pc->p[0] = last_seg->finalPoint();
 788             pc->npoints = 1;
 789             Geom::Point const req_vec( pc->p[0] - (*last_seg)[2] );
 790             pc->req_tangent = ( ( Geom::is_zero(req_vec) || !in_svg_plane(req_vec) )
 791                                 ? Geom::Point(0, 0)
 792                                 : Geom::unit_vector(req_vec) );
 793         }
 794     }
 795     g_free(b);
 796     g_free(points);
 797     pc->ps.clear();
 798 }
 799
 800
 801 /* interpolates the sketched curve and tweaks the current sketch interpolation*/
 802 static void
 803 sketch_interpolate(SPPencilContext *pc)
 804 {
 805     if ( pc->ps.size() <= 1 ) {
 806         return;
 807     }
 808
 809     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 810     double const tol = prefs->getDoubleLimited("/tools/freehand/pencil/tolerance", 10.0, 1.0, 100.0) * 0.4;
 811     double const tolerance_sq = 0.02 * square( pc->desktop->w2d().descrim() *
 812                                                tol) * exp(0.2*tol - 2);
 813
 814     bool average_all_sketches = prefs->getBool("/tools/freehand/pencil/average_all_sketches", true);
 815
 816     g_assert(is_zero(pc->req_tangent)
 817              || is_unit_vector(pc->req_tangent));
 818     Geom::Point const tHatEnd(0, 0);
 819
 820     guint n_points  = pc->ps.size();
 821     pc->red_curve->reset();
 822     pc->red_curve_is_valid = false;
 823
 824     Geom::Point * b = g_new(Geom::Point, 4*n_points);
 825     Geom::Point * points = g_new(Geom::Point, 4*n_points);
 826     for (unsigned i = 0; i < pc->ps.size(); i++) {
 827         points[i] = pc->ps[i];
 828     }
 829
 830     // worst case gives us a segment per point
 831     int max_segs = 4*n_points;
 832
 833     int const n_segs = Geom::bezier_fit_cubic_r(b, points, n_points,
 834                                              tolerance_sq, max_segs);
 835
 836     if ( n_segs > 0)
 837     {
 838         Geom::Path fit(b[0]);
 839         for (int c = 0; c < n_segs; c++) {
 840             fit.appendNew<Geom::CubicBezier>(b[4*c+1], b[4*c+2], b[4*c+3]);
 841         }
 842         Geom::Piecewise<Geom::D2<Geom::SBasis> > fit_pwd2 = fit.toPwSb();
 843
 844         double t =0.;
 845         if ( pc->sketch_n > 0 ) {
 846             if (average_all_sketches) {
 847                 // Average = (sum of all) / n
 848                 //         = (sum of all + new one) / n+1
 849                 //         = ((old average)*n + new one) / n+1
 850                 t = pc->sketch_n / (pc->sketch_n + 1.);
 851             } else {
 852                 t = 0.5;
 853             }
 854             pc->sketch_interpolation = Geom::lerp(t, fit_pwd2, pc->sketch_interpolation);
 855             // simplify path, to eliminate small segments
 856             Path *path = new Path;
 857             path->LoadPathVector(Geom::path_from_piecewise(pc->sketch_interpolation, 0.01));
 858             path->Simplify(0.5);
 859             Geom::PathVector *pathv = path->MakePathVector();
 860             pc->sketch_interpolation = (*pathv)[0].toPwSb();
 861             delete path;
 862             delete pathv;
 863         } else {
 864             pc->sketch_interpolation = fit_pwd2;
 865         }
 866         pc->sketch_n++;
 867
 868         pc->green_curve->reset();
 869         pc->green_curve->set_pathvector(Geom::path_from_piecewise(pc->sketch_interpolation, 0.01));
 870         sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), pc->green_curve);
 871
 872         /* Fit and draw and copy last point */
 873         g_assert(!pc->green_curve->is_empty());
 874
 875         /* Set up direction of next curve. */
 876         {
 877             Geom::CubicBezier const * last_seg = dynamic_cast<Geom::CubicBezier const *>(pc->green_curve->last_segment());
 878             g_assert( last_seg );      // Relevance: validity of (*last_seg)[2]
 879             pc->p[0] = last_seg->finalPoint();
 880             pc->npoints = 1;
 881             Geom::Point const req_vec( pc->p[0] - (*last_seg)[2] );
 882             pc->req_tangent = ( ( Geom::is_zero(req_vec) || !in_svg_plane(req_vec) )
 883                                 ? Geom::Point(0, 0)
 884                                 : Geom::unit_vector(req_vec) );
 885         }
 886     }
 887     g_free(b);
 888     g_free(points);
 889     pc->ps.clear();
 890 }
 891
 892 static void
 893 fit_and_split(SPPencilContext *pc)
 894 {
 895     g_assert( pc->npoints > 1 );
 896
 897     double const tolerance_sq = 0;
 898
 899     Geom::Point b[4];
 900     g_assert(is_zero(pc->req_tangent)
 901              || is_unit_vector(pc->req_tangent));
 902     Geom::Point const tHatEnd(0, 0);
 903     int const n_segs = Geom::bezier_fit_cubic_full(b, NULL, pc->p, pc->npoints,
 904                                                 pc->req_tangent, tHatEnd,
 905                                                 tolerance_sq, 1);
 906     if ( n_segs > 0
 907          && unsigned(pc->npoints) < G_N_ELEMENTS(pc->p) )
 908     {
 909         /* Fit and draw and reset state */
 910         pc->red_curve->reset();
 911         pc->red_curve->moveto(b[0]);
 912         pc->red_curve->curveto(b[1], b[2], b[3]);
 913         sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), pc->red_curve);
 914         pc->red_curve_is_valid = true;
 915     } else {
 916         /* Fit and draw and copy last point */
 917
 918         g_assert(!pc->red_curve->is_empty());
 919
 920         /* Set up direction of next curve. */
 921         {
 922             Geom::CubicBezier const * last_seg = dynamic_cast<Geom::CubicBezier const *>(pc->red_curve->last_segment());
 923             g_assert( last_seg );      // Relevance: validity of (*last_seg)[2]
 924             pc->p[0] = last_seg->finalPoint();
 925             pc->npoints = 1;
 926             Geom::Point const req_vec( pc->p[0] - (*last_seg)[2] );
 927             pc->req_tangent = ( ( Geom::is_zero(req_vec) || !in_svg_plane(req_vec) )
 928                                 ? Geom::Point(0, 0)
 929                                 : Geom::unit_vector(req_vec) );
 930         }
 931
 932         pc->green_curve->append_continuous(pc->red_curve, 0.0625);
 933         SPCurve *curve = pc->red_curve->copy();
 934
 935         /// \todo fixme:
 936         SPCanvasItem *cshape = sp_canvas_bpath_new(sp_desktop_sketch(pc->desktop), curve);
 937         curve->unref();
 938         sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(cshape), pc->green_color, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 939
 940         pc->green_bpaths = g_slist_prepend(pc->green_bpaths, cshape);
 941
 942         pc->red_curve_is_valid = false;
 943     }
 944 }
 945
 946
 947 /*
 948   Local Variables:
 949   mode:c++
 950   c-file-style:"stroustrup"
 951   c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
 952   indent-tabs-mode:nil
 953   fill-column:99
 954   End:
 955 */
 956 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :