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