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