src/dyna-draw-context.cpp

   1 /*
   2  * Handwriting-like drawing mode
   3  *
   4  * Authors:
   5  *   Mitsuru Oka <oka326@parkcity.ne.jp>
   6  *   Lauris Kaplinski <lauris@kaplinski.com>
   7  *   bulia byak <buliabyak@users.sf.net>
   8  *   MenTaLguY <mental@rydia.net>
   9  *   Abhishek Sharma
  10  *
  11  * The original dynadraw code:
  12  *   Paul Haeberli <paul@sgi.com>
  13  *
  14  * Copyright (C) 1998 The Free Software Foundation
  15  * Copyright (C) 1999-2005 authors
  16  * Copyright (C) 2001-2002 Ximian, Inc.
  17  * Copyright (C) 2005-2007 bulia byak
  18  * Copyright (C) 2006 MenTaLguY
  19  *
  20  * Released under GNU GPL, read the file 'COPYING' for more information
  21  */
  22
  23 #define noDYNA_DRAW_VERBOSE
  24
  25 #include "config.h"
  26
  27 #include <gtk/gtk.h>
  28 #include <gdk/gdkkeysyms.h>
  29 #include <glibmm/i18n.h>
  30 #include <string>
  31 #include <cstring>
  32 #include <numeric>
  33
  34 #include "svg/svg.h"
  35 #include "display/canvas-bpath.h"
  36 #include <2geom/isnan.h>
  37 #include <2geom/pathvector.h>
  38 #include <2geom/bezier-utils.h>
  39 #include "display/curve.h"
  40 #include <glib/gmem.h>
  41 #include "macros.h"
  42 #include "document.h"
  43 #include "selection.h"
  44 #include "desktop.h"
  45 #include "desktop-events.h"
  46 #include "desktop-handles.h"
  47 #include "desktop-style.h"
  48 #include "message-context.h"
  49 #include "preferences.h"
  50 #include "pixmaps/cursor-calligraphy.xpm"
  51 #include "xml/repr.h"
  52 #include "context-fns.h"
  53 #include "sp-item.h"
  54 #include "inkscape.h"
  55 #include "color.h"
  56 #include "splivarot.h"
  57 #include "sp-item-group.h"
  58 #include "sp-shape.h"
  59 #include "sp-path.h"
  60 #include "sp-text.h"
  61 #include "display/canvas-bpath.h"
  62 #include "display/canvas-arena.h"
  63 #include "livarot/Shape.h"
  64
  65 #include "dyna-draw-context.h"
  66
  67 using Inkscape::DocumentUndo;
  68
  69 #define DDC_RED_RGBA 0xff0000ff
  70
  71 #define TOLERANCE_CALLIGRAPHIC 0.1
  72
  73 #define DYNA_EPSILON 0.5e-6
  74 #define DYNA_EPSILON_START 0.5e-2
  75 #define DYNA_VEL_START 1e-5
  76
  77 #define DYNA_MIN_WIDTH 1.0e-6
  78
  79 static void sp_dyna_draw_context_class_init(SPDynaDrawContextClass *klass);
  80 static void sp_dyna_draw_context_init(SPDynaDrawContext *ddc);
  81 static void sp_dyna_draw_context_dispose(GObject *object);
  82
  83 static void sp_dyna_draw_context_setup(SPEventContext *ec);
  84 static void sp_dyna_draw_context_set(SPEventContext *ec, Inkscape::Preferences::Entry *value);
  85 static gint sp_dyna_draw_context_root_handler(SPEventContext *ec, GdkEvent *event);
  86
  87 static void clear_current(SPDynaDrawContext *dc);
  88 static void set_to_accumulated(SPDynaDrawContext *dc, bool unionize, bool subtract);
  89 static void add_cap(SPCurve *curve, Geom::Point const &from, Geom::Point const &to, double rounding);
  90 static bool accumulate_calligraphic(SPDynaDrawContext *dc);
  91
  92 static void fit_and_split(SPDynaDrawContext *ddc, gboolean release);
  93
  94 static void sp_dyna_draw_reset(SPDynaDrawContext *ddc, Geom::Point p);
  95 static Geom::Point sp_dyna_draw_get_npoint(SPDynaDrawContext const *ddc, Geom::Point v);
  96 static Geom::Point sp_dyna_draw_get_vpoint(SPDynaDrawContext const *ddc, Geom::Point n);
  97 static void draw_temporary_box(SPDynaDrawContext *dc);
  98
  99
 100 static SPEventContextClass *dd_parent_class = 0;
 101
 102 GType sp_dyna_draw_context_get_type(void)
 103 {
 104     static GType type = 0;
 105     if (!type) {
 106         GTypeInfo info = {
 107             sizeof(SPDynaDrawContextClass),
 108             0, // base_init
 109             0, // base_finalize
 110             (GClassInitFunc)sp_dyna_draw_context_class_init,
 111             0, // class_finalize
 112             0, // class_data
 113             sizeof(SPDynaDrawContext),
 114             0, // n_preallocs
 115             (GInstanceInitFunc)sp_dyna_draw_context_init,
 116             0 // value_table
 117         };
 118         type = g_type_register_static(SP_TYPE_COMMON_CONTEXT, "SPDynaDrawContext", &info, static_cast<GTypeFlags>(0));
 119     }
 120     return type;
 121 }
 122
 123 static void
 124 sp_dyna_draw_context_class_init(SPDynaDrawContextClass *klass)
 125 {
 126     GObjectClass *object_class = (GObjectClass *) klass;
 127     SPEventContextClass *event_context_class = (SPEventContextClass *) klass;
 128
 129     dd_parent_class = (SPEventContextClass*)g_type_class_peek_parent(klass);
 130
 131     object_class->dispose = sp_dyna_draw_context_dispose;
 132
 133     event_context_class->setup = sp_dyna_draw_context_setup;
 134     event_context_class->set = sp_dyna_draw_context_set;
 135     event_context_class->root_handler = sp_dyna_draw_context_root_handler;
 136 }
 137
 138 static void
 139 sp_dyna_draw_context_init(SPDynaDrawContext *ddc)
 140 {
 141     ddc->cursor_shape = cursor_calligraphy_xpm;
 142     ddc->hot_x = 4;
 143     ddc->hot_y = 4;
 144
 145     ddc->vel_thin = 0.1;
 146     ddc->flatness = 0.9;
 147     ddc->cap_rounding = 0.0;
 148
 149     ddc->abs_width = false;
 150     ddc->keep_selected = true;
 151
 152     ddc->hatch_spacing = 0;
 153     ddc->hatch_spacing_step = 0;
 154     new (&ddc->hatch_pointer_past) std::list<double>();
 155     new (&ddc->hatch_nearest_past) std::list<double>();
 156     new (&ddc->inertia_vectors) std::list<Geom::Point>();
 157     new (&ddc->hatch_vectors) std::list<Geom::Point>();
 158     ddc->hatch_last_nearest = Geom::Point(0,0);
 159     ddc->hatch_last_pointer = Geom::Point(0,0);
 160     ddc->hatch_escaped = false;
 161     ddc->hatch_area = NULL;
 162     ddc->hatch_item = NULL;
 163     ddc->hatch_livarot_path = NULL;
 164
 165     ddc->trace_bg = false;
 166     ddc->just_started_drawing = false;
 167 }
 168
 169 static void
 170 sp_dyna_draw_context_dispose(GObject *object)
 171 {
 172     SPDynaDrawContext *ddc = SP_DYNA_DRAW_CONTEXT(object);
 173
 174     if (ddc->hatch_area) {
 175         gtk_object_destroy(GTK_OBJECT(ddc->hatch_area));
 176         ddc->hatch_area = NULL;
 177     }
 178
 179
 180     G_OBJECT_CLASS(dd_parent_class)->dispose(object);
 181
 182     ddc->hatch_pointer_past.~list();
 183     ddc->hatch_nearest_past.~list();
 184     ddc->inertia_vectors.~list();
 185     ddc->hatch_vectors.~list();
 186 }
 187
 188 static void
 189 sp_dyna_draw_context_setup(SPEventContext *ec)
 190 {
 191     SPDynaDrawContext *ddc = SP_DYNA_DRAW_CONTEXT(ec);
 192
 193     if (((SPEventContextClass *) dd_parent_class)->setup)
 194         ((SPEventContextClass *) dd_parent_class)->setup(ec);
 195
 196     ddc->accumulated = new SPCurve();
 197     ddc->currentcurve = new SPCurve();
 198
 199     ddc->cal1 = new SPCurve();
 200     ddc->cal2 = new SPCurve();
 201
 202     ddc->currentshape = sp_canvas_item_new(sp_desktop_sketch(ec->desktop), SP_TYPE_CANVAS_BPATH, NULL);
 203     sp_canvas_bpath_set_fill(SP_CANVAS_BPATH(ddc->currentshape), DDC_RED_RGBA, SP_WIND_RULE_EVENODD);
 204     sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(ddc->currentshape), 0x00000000, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 205     /* fixme: Cannot we cascade it to root more clearly? */
 206     g_signal_connect(G_OBJECT(ddc->currentshape), "event", G_CALLBACK(sp_desktop_root_handler), ec->desktop);
 207
 208     {
 209         /* TODO: this can be done either with an arcto, and should maybe also be put in a general file (other tools use this as well) */
 210         SPCurve *c = new SPCurve();
 211         const double C1 = 0.552;
 212         c->moveto(-1,0);
 213         c->curveto(-1, C1, -C1, 1, 0, 1 );
 214         c->curveto(C1, 1, 1, C1, 1, 0 );
 215         c->curveto(1, -C1, C1, -1, 0, -1 );
 216         c->curveto(-C1, -1, -1, -C1, -1, 0 );
 217         c->closepath();
 218         ddc->hatch_area = sp_canvas_bpath_new(sp_desktop_controls(ec->desktop), c);
 219         c->unref();
 220         sp_canvas_bpath_set_fill(SP_CANVAS_BPATH(ddc->hatch_area), 0x00000000,(SPWindRule)0);
 221         sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(ddc->hatch_area), 0x0000007f, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 222         sp_canvas_item_hide(ddc->hatch_area);
 223     }
 224
 225     sp_event_context_read(ec, "mass");
 226     sp_event_context_read(ec, "wiggle");
 227     sp_event_context_read(ec, "angle");
 228     sp_event_context_read(ec, "width");
 229     sp_event_context_read(ec, "thinning");
 230     sp_event_context_read(ec, "tremor");
 231     sp_event_context_read(ec, "flatness");
 232     sp_event_context_read(ec, "tracebackground");
 233     sp_event_context_read(ec, "usepressure");
 234     sp_event_context_read(ec, "usetilt");
 235     sp_event_context_read(ec, "abs_width");
 236     sp_event_context_read(ec, "keep_selected");
 237     sp_event_context_read(ec, "cap_rounding");
 238
 239     ddc->is_drawing = false;
 240     ddc->_message_context = new Inkscape::MessageContext((ec->desktop)->messageStack());
 241
 242     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 243     if (prefs->getBool("/tools/calligraphic/selcue")) {
 244         ec->enableSelectionCue();
 245     }
 246 }
 247
 248 static void
 249 sp_dyna_draw_context_set(SPEventContext *ec, Inkscape::Preferences::Entry *val)
 250 {
 251     SPDynaDrawContext *ddc = SP_DYNA_DRAW_CONTEXT(ec);
 252     Glib::ustring path = val->getEntryName();
 253
 254     if (path == "tracebackground") {
 255         ddc->trace_bg = val->getBool();
 256     } else if (path == "keep_selected") {
 257         ddc->keep_selected = val->getBool();
 258     } else {
 259         //pass on up to parent class to handle common attributes.
 260         if ( dd_parent_class->set ) {
 261             dd_parent_class->set(ec, val);
 262         }
 263     }
 264
 265     //g_print("DDC: %g %g %g %g\n", ddc->mass, ddc->drag, ddc->angle, ddc->width);
 266 }
 267
 268 static double
 269 flerp(double f0, double f1, double p)
 270 {
 271     return f0 + ( f1 - f0 ) * p;
 272 }
 273
 274 /* Get normalized point */
 275 static Geom::Point
 276 sp_dyna_draw_get_npoint(SPDynaDrawContext const *dc, Geom::Point v)
 277 {
 278     Geom::Rect drect = SP_EVENT_CONTEXT(dc)->desktop->get_display_area();
 279     double const max = MAX ( drect.dimensions()[Geom::X], drect.dimensions()[Geom::Y] );
 280     return Geom::Point(( v[Geom::X] - drect.min()[Geom::X] ) / max,  ( v[Geom::Y] - drect.min()[Geom::Y] ) / max);
 281 }
 282
 283 /* Get view point */
 284 static Geom::Point
 285 sp_dyna_draw_get_vpoint(SPDynaDrawContext const *dc, Geom::Point n)
 286 {
 287     Geom::Rect drect = SP_EVENT_CONTEXT(dc)->desktop->get_display_area();
 288     double const max = MAX ( drect.dimensions()[Geom::X], drect.dimensions()[Geom::Y] );
 289     return Geom::Point(n[Geom::X] * max + drect.min()[Geom::X], n[Geom::Y] * max + drect.min()[Geom::Y]);
 290 }
 291
 292 static void
 293 sp_dyna_draw_reset(SPDynaDrawContext *dc, Geom::Point p)
 294 {
 295     dc->last = dc->cur = sp_dyna_draw_get_npoint(dc, p);
 296     dc->vel = Geom::Point(0,0);
 297     dc->vel_max = 0;
 298     dc->acc = Geom::Point(0,0);
 299     dc->ang = Geom::Point(0,0);
 300     dc->del = Geom::Point(0,0);
 301 }
 302
 303 static void
 304 sp_dyna_draw_extinput(SPDynaDrawContext *dc, GdkEvent *event)
 305 {
 306     if (gdk_event_get_axis (event, GDK_AXIS_PRESSURE, &dc->pressure))
 307         dc->pressure = CLAMP (dc->pressure, DDC_MIN_PRESSURE, DDC_MAX_PRESSURE);
 308     else
 309         dc->pressure = DDC_DEFAULT_PRESSURE;
 310
 311     if (gdk_event_get_axis (event, GDK_AXIS_XTILT, &dc->xtilt))
 312         dc->xtilt = CLAMP (dc->xtilt, DDC_MIN_TILT, DDC_MAX_TILT);
 313     else
 314         dc->xtilt = DDC_DEFAULT_TILT;
 315
 316     if (gdk_event_get_axis (event, GDK_AXIS_YTILT, &dc->ytilt))
 317         dc->ytilt = CLAMP (dc->ytilt, DDC_MIN_TILT, DDC_MAX_TILT);
 318     else
 319         dc->ytilt = DDC_DEFAULT_TILT;
 320 }
 321
 322
 323 static gboolean
 324 sp_dyna_draw_apply(SPDynaDrawContext *dc, Geom::Point p)
 325 {
 326     Geom::Point n = sp_dyna_draw_get_npoint(dc, p);
 327
 328     /* Calculate mass and drag */
 329     double const mass = flerp(1.0, 160.0, dc->mass);
 330     double const drag = flerp(0.0, 0.5, dc->drag * dc->drag);
 331
 332     /* Calculate force and acceleration */
 333     Geom::Point force = n - dc->cur;
 334
 335     // If force is below the absolute threshold DYNA_EPSILON,
 336     // or we haven't yet reached DYNA_VEL_START (i.e. at the beginning of stroke)
 337     // _and_ the force is below the (higher) DYNA_EPSILON_START threshold,
 338     // discard this move.
 339     // This prevents flips, blobs, and jerks caused by microscopic tremor of the tablet pen,
 340     // especially bothersome at the start of the stroke where we don't yet have the inertia to
 341     // smooth them out.
 342     if ( Geom::L2(force) < DYNA_EPSILON || (dc->vel_max < DYNA_VEL_START && Geom::L2(force) < DYNA_EPSILON_START)) {
 343         return FALSE;
 344     }
 345
 346     dc->acc = force / mass;
 347
 348     /* Calculate new velocity */
 349     dc->vel += dc->acc;
 350
 351     if (Geom::L2(dc->vel) > dc->vel_max)
 352         dc->vel_max = Geom::L2(dc->vel);
 353
 354     /* Calculate angle of drawing tool */
 355
 356     double a1;
 357     if (dc->usetilt) {
 358         // 1a. calculate nib angle from input device tilt:
 359         gdouble length = std::sqrt(dc->xtilt*dc->xtilt + dc->ytilt*dc->ytilt);;
 360
 361         if (length > 0) {
 362             Geom::Point ang1 = Geom::Point(dc->ytilt/length, dc->xtilt/length);
 363             a1 = atan2(ang1);
 364         }
 365         else
 366             a1 = 0.0;
 367     }
 368     else {
 369         // 1b. fixed dc->angle (absolutely flat nib):
 370         double const radians = ( (dc->angle - 90) / 180.0 ) * M_PI;
 371         Geom::Point ang1 = Geom::Point(-sin(radians),  cos(radians));
 372         a1 = atan2(ang1);
 373     }
 374
 375     // 2. perpendicular to dc->vel (absolutely non-flat nib):
 376     gdouble const mag_vel = Geom::L2(dc->vel);
 377     if ( mag_vel < DYNA_EPSILON ) {
 378         return FALSE;
 379     }
 380     Geom::Point ang2 = Geom::rot90(dc->vel) / mag_vel;
 381
 382     // 3. Average them using flatness parameter:
 383     // calculate angles
 384     double a2 = atan2(ang2);
 385     // flip a2 to force it to be in the same half-circle as a1
 386     bool flipped = false;
 387     if (fabs (a2-a1) > 0.5*M_PI) {
 388         a2 += M_PI;
 389         flipped = true;
 390     }
 391     // normalize a2
 392     if (a2 > M_PI)
 393         a2 -= 2*M_PI;
 394     if (a2 < -M_PI)
 395         a2 += 2*M_PI;
 396     // find the flatness-weighted bisector angle, unflip if a2 was flipped
 397     // FIXME: when dc->vel is oscillating around the fixed angle, the new_ang flips back and forth. How to avoid this?
 398     double new_ang = a1 + (1 - dc->flatness) * (a2 - a1) - (flipped? M_PI : 0);
 399
 400     // Try to detect a sudden flip when the new angle differs too much from the previous for the
 401     // current velocity; in that case discard this move
 402     double angle_delta = Geom::L2(Geom::Point (cos (new_ang), sin (new_ang)) - dc->ang);
 403     if ( angle_delta / Geom::L2(dc->vel) > 4000 ) {
 404         return FALSE;
 405     }
 406
 407     // convert to point
 408     dc->ang = Geom::Point (cos (new_ang), sin (new_ang));
 409
 410 //    g_print ("force %g  acc %g  vel_max %g  vel %g  a1 %g  a2 %g  new_ang %g\n", Geom::L2(force), Geom::L2(dc->acc), dc->vel_max, Geom::L2(dc->vel), a1, a2, new_ang);
 411
 412     /* Apply drag */
 413     dc->vel *= 1.0 - drag;
 414
 415     /* Update position */
 416     dc->last = dc->cur;
 417     dc->cur += dc->vel;
 418
 419     return TRUE;
 420 }
 421
 422 static void
 423 sp_dyna_draw_brush(SPDynaDrawContext *dc)
 424 {
 425     g_assert( dc->npoints >= 0 && dc->npoints < SAMPLING_SIZE );
 426
 427     // How much velocity thins strokestyle
 428     double vel_thin = flerp (0, 160, dc->vel_thin);
 429
 430     // Influence of pressure on thickness
 431     double pressure_thick = (dc->usepressure ? dc->pressure : 1.0);
 432
 433     // get the real brush point, not the same as pointer (affected by hatch tracking and/or mass
 434     // drag)
 435     Geom::Point brush = sp_dyna_draw_get_vpoint(dc, dc->cur);
 436     Geom::Point brush_w = SP_EVENT_CONTEXT(dc)->desktop->d2w(brush);
 437
 438     double trace_thick = 1;
 439     if (dc->trace_bg) {
 440         // pick single pixel
 441         NRPixBlock pb;
 442         int x = (int) floor(brush_w[Geom::X]);
 443         int y = (int) floor(brush_w[Geom::Y]);
 444         nr_pixblock_setup_fast(&pb, NR_PIXBLOCK_MODE_R8G8B8A8P, x, y, x+1, y+1, TRUE);
 445         sp_canvas_arena_render_pixblock(SP_CANVAS_ARENA(sp_desktop_drawing(SP_EVENT_CONTEXT(dc)->desktop)), &pb);
 446         const unsigned char *s = NR_PIXBLOCK_PX(&pb);
 447         double R = s[0] / 255.0;
 448         double G = s[1] / 255.0;
 449         double B = s[2] / 255.0;
 450         double A = s[3] / 255.0;
 451         double max = MAX (MAX (R, G), B);
 452         double min = MIN (MIN (R, G), B);
 453         double L = A * (max + min)/2 + (1 - A); // blend with white bg
 454         trace_thick = 1 - L;
 455         //g_print ("L %g thick %g\n", L, trace_thick);
 456     }
 457
 458     double width = (pressure_thick * trace_thick - vel_thin * Geom::L2(dc->vel)) * dc->width;
 459
 460     double tremble_left = 0, tremble_right = 0;
 461     if (dc->tremor > 0) {
 462         // obtain two normally distributed random variables, using polar Box-Muller transform
 463         double x1, x2, w, y1, y2;
 464         do {
 465             x1 = 2.0 * g_random_double_range(0,1) - 1.0;
 466             x2 = 2.0 * g_random_double_range(0,1) - 1.0;
 467             w = x1 * x1 + x2 * x2;
 468         } while ( w >= 1.0 );
 469         w = sqrt( (-2.0 * log( w ) ) / w );
 470         y1 = x1 * w;
 471         y2 = x2 * w;
 472
 473         // deflect both left and right edges randomly and independently, so that:
 474         // (1) dc->tremor=1 corresponds to sigma=1, decreasing dc->tremor narrows the bell curve;
 475         // (2) deflection depends on width, but is upped for small widths for better visual uniformity across widths;
 476         // (3) deflection somewhat depends on speed, to prevent fast strokes looking
 477         // comparatively smooth and slow ones excessively jittery
 478         tremble_left  = (y1)*dc->tremor * (0.15 + 0.8*width) * (0.35 + 14*Geom::L2(dc->vel));
 479         tremble_right = (y2)*dc->tremor * (0.15 + 0.8*width) * (0.35 + 14*Geom::L2(dc->vel));
 480     }
 481
 482     if ( width < 0.02 * dc->width ) {
 483         width = 0.02 * dc->width;
 484     }
 485
 486     double dezoomify_factor = 0.05 * 1000;
 487     if (!dc->abs_width) {
 488         dezoomify_factor /= SP_EVENT_CONTEXT(dc)->desktop->current_zoom();
 489     }
 490
 491     Geom::Point del_left = dezoomify_factor * (width + tremble_left) * dc->ang;
 492     Geom::Point del_right = dezoomify_factor * (width + tremble_right) * dc->ang;
 493
 494     dc->point1[dc->npoints] = brush + del_left;
 495     dc->point2[dc->npoints] = brush - del_right;
 496
 497     dc->del = 0.5*(del_left + del_right);
 498
 499     dc->npoints++;
 500 }
 501
 502 void
 503 sp_ddc_update_toolbox (SPDesktop *desktop, const gchar *id, double value)
 504 {
 505     desktop->setToolboxAdjustmentValue (id, value);
 506 }
 507
 508 static void
 509 calligraphic_cancel(SPDynaDrawContext *dc)
 510 {
 511     SPDesktop *desktop = SP_EVENT_CONTEXT(dc)->desktop;
 512     dc->dragging = FALSE;
 513     dc->is_drawing = false;
 514     sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate), 0);
 515             /* Remove all temporary line segments */
 516             while (dc->segments) {
 517                 gtk_object_destroy(GTK_OBJECT(dc->segments->data));
 518                 dc->segments = g_slist_remove(dc->segments, dc->segments->data);
 519             }
 520             /* reset accumulated curve */
 521             dc->accumulated->reset();
 522             clear_current(dc);
 523             if (dc->repr) {
 524                 dc->repr = NULL;
 525             }
 526 }
 527
 528
 529 gint
 530 sp_dyna_draw_context_root_handler(SPEventContext *event_context,
 531                                   GdkEvent *event)
 532 {
 533     SPDynaDrawContext *dc = SP_DYNA_DRAW_CONTEXT(event_context);
 534     SPDesktop *desktop = event_context->desktop;
 535
 536     gint ret = FALSE;
 537
 538     switch (event->type) {
 539         case GDK_BUTTON_PRESS:
 540             if (event->button.button == 1 && !event_context->space_panning) {
 541
 542                 SPDesktop *desktop = SP_EVENT_CONTEXT_DESKTOP(dc);
 543
 544                 if (Inkscape::have_viable_layer(desktop, dc->_message_context) == false) {
 545                     return TRUE;
 546                 }
 547
 548                 dc->accumulated->reset();
 549                 if (dc->repr) {
 550                     dc->repr = NULL;
 551                 }
 552
 553                 /* initialize first point */
 554                 dc->npoints = 0;
 555
 556                 sp_canvas_item_grab(SP_CANVAS_ITEM(desktop->acetate),
 557                                     ( GDK_KEY_PRESS_MASK |
 558                                       GDK_BUTTON_RELEASE_MASK |
 559                                       GDK_POINTER_MOTION_MASK |
 560                                       GDK_BUTTON_PRESS_MASK ),
 561                                     NULL,
 562                                     event->button.time);
 563
 564                 ret = TRUE;
 565
 566                 sp_canvas_force_full_redraw_after_interruptions(desktop->canvas, 3);
 567                 dc->is_drawing = true;
 568                 dc->just_started_drawing = true;
 569             }
 570             break;
 571         case GDK_MOTION_NOTIFY:
 572         {
 573             Geom::Point const motion_w(event->motion.x,
 574                                      event->motion.y);
 575             Geom::Point motion_dt(desktop->w2d(motion_w));
 576             sp_dyna_draw_extinput(dc, event);
 577
 578             dc->_message_context->clear();
 579
 580             // for hatching:
 581             double hatch_dist = 0;
 582             Geom::Point hatch_unit_vector(0,0);
 583             Geom::Point nearest(0,0);
 584             Geom::Point pointer(0,0);
 585             Geom::Matrix motion_to_curve(Geom::identity());
 586
 587             if (event->motion.state & GDK_CONTROL_MASK) { // hatching - sense the item
 588
 589                 SPItem *selected = sp_desktop_selection(desktop)->singleItem();
 590                 if (selected && (SP_IS_SHAPE(selected) || SP_IS_TEXT(selected))) {
 591                     // One item selected, and it's a path;
 592                     // let's try to track it as a guide
 593
 594                     if (selected != dc->hatch_item) {
 595                         dc->hatch_item = selected;
 596                         if (dc->hatch_livarot_path)
 597                             delete dc->hatch_livarot_path;
 598                         dc->hatch_livarot_path = Path_for_item (dc->hatch_item, true, true);
 599                         dc->hatch_livarot_path->ConvertWithBackData(0.01);
 600                     }
 601
 602                     // calculate pointer point in the guide item's coords
 603                     motion_to_curve = selected->dt2i_affine() * selected->i2doc_affine();
 604                     pointer = motion_dt * motion_to_curve;
 605
 606                     // calculate the nearest point on the guide path
 607                     boost::optional<Path::cut_position> position = get_nearest_position_on_Path(dc->hatch_livarot_path, pointer);
 608                     nearest = get_point_on_Path(dc->hatch_livarot_path, position->piece, position->t);
 609
 610
 611                     // distance from pointer to nearest
 612                     hatch_dist = Geom::L2(pointer - nearest);
 613                     // unit-length vector
 614                     hatch_unit_vector = (pointer - nearest)/hatch_dist;
 615
 616                     dc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("<b>Guide path selected</b>; start drawing along the guide with <b>Ctrl</b>"));
 617                 } else {
 618                     dc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("<b>Select a guide path</b> to track with <b>Ctrl</b>"));
 619                 }
 620             }
 621
 622             if ( dc->is_drawing && (event->motion.state & GDK_BUTTON1_MASK) && !event_context->space_panning) {
 623                 dc->dragging = TRUE;
 624
 625                 if (event->motion.state & GDK_CONTROL_MASK && dc->hatch_item) { // hatching
 626
 627 #define HATCH_VECTOR_ELEMENTS 12
 628 #define INERTIA_ELEMENTS 24
 629 #define SPEED_ELEMENTS 12
 630 #define SPEED_MIN 0.3
 631 #define SPEED_NORMAL 0.35
 632 #define INERTIA_FORCE 0.5
 633
 634                     // speed is the movement of the nearest point along the guide path, divided by
 635                     // the movement of the pointer at the same period; it is averaged for the last
 636                     // SPEED_ELEMENTS motion events.  Normally, as you track the guide path, speed
 637                     // is about 1, i.e. the nearest point on the path is moved by about the same
 638                     // distance as the pointer. If the speed starts to decrease, we are losing
 639                     // contact with the guide; if it drops below SPEED_MIN, we are on our own and
 640                     // not attracted to guide anymore. Most often this happens when you have
 641                     // tracked to the end of a guide calligraphic stroke and keep moving
 642                     // further. We try to handle this situation gracefully: not stick with the
 643                     // guide forever but let go of it smoothly and without sharp jerks (non-zero
 644                     // mass recommended; with zero mass, jerks are still quite noticeable).
 645
 646                     double speed = 1;
 647                     if (Geom::L2(dc->hatch_last_nearest) != 0) {
 648                         // the distance nearest moved since the last motion event
 649                         double nearest_moved = Geom::L2(nearest - dc->hatch_last_nearest);
 650                         // the distance pointer moved since the last motion event
 651                         double pointer_moved = Geom::L2(pointer - dc->hatch_last_pointer);
 652                         // store them in stacks limited to SPEED_ELEMENTS
 653                         dc->hatch_nearest_past.push_front(nearest_moved);
 654                         if (dc->hatch_nearest_past.size() > SPEED_ELEMENTS)
 655                             dc->hatch_nearest_past.pop_back();
 656                         dc->hatch_pointer_past.push_front(pointer_moved);
 657                         if (dc->hatch_pointer_past.size() > SPEED_ELEMENTS)
 658                             dc->hatch_pointer_past.pop_back();
 659
 660                         // If the stacks are full,
 661                         if (dc->hatch_nearest_past.size() == SPEED_ELEMENTS) {
 662                             // calculate the sums of all stored movements
 663                             double nearest_sum = std::accumulate (dc->hatch_nearest_past.begin(), dc->hatch_nearest_past.end(), 0.0);
 664                             double pointer_sum = std::accumulate (dc->hatch_pointer_past.begin(), dc->hatch_pointer_past.end(), 0.0);
 665                             // and divide to get the speed
 666                             speed = nearest_sum/pointer_sum;
 667                             //g_print ("nearest sum %g  pointer_sum %g  speed %g\n", nearest_sum, pointer_sum, speed);
 668                         }
 669                     }
 670
 671                     if (   dc->hatch_escaped  // already escaped, do not reattach
 672                         || (speed < SPEED_MIN) // stuck; most likely reached end of traced stroke
 673                         || (dc->hatch_spacing > 0 && hatch_dist > 50 * dc->hatch_spacing) // went too far from the guide
 674                         ) {
 675                         // We are NOT attracted to the guide!
 676
 677                         //g_print ("\nlast_nearest %g %g   nearest %g %g  pointer %g %g  pos %d %g\n", dc->last_nearest[Geom::X], dc->last_nearest[Geom::Y], nearest[Geom::X], nearest[Geom::Y], pointer[Geom::X], pointer[Geom::Y], position->piece, position->t);
 678
 679                         // Remember hatch_escaped so we don't get
 680                         // attracted again until the end of this stroke
 681                         dc->hatch_escaped = true;
 682
 683                         if (dc->inertia_vectors.size() >= INERTIA_ELEMENTS/2) { // move by inertia
 684                             Geom::Point moved_past_escape = motion_dt - dc->inertia_vectors.front();
 685                             Geom::Point inertia =
 686                                 dc->inertia_vectors.front() - dc->inertia_vectors.back();
 687
 688                             double dot = Geom::dot (moved_past_escape, inertia);
 689                             dot /= Geom::L2(moved_past_escape) * Geom::L2(inertia);
 690
 691                             if (dot > 0) { // mouse is still moving in approx the same direction
 692                                 Geom::Point should_have_moved =
 693                                     (inertia) * (1/Geom::L2(inertia)) * Geom::L2(moved_past_escape);
 694                                 motion_dt = dc->inertia_vectors.front() +
 695                                     (INERTIA_FORCE * should_have_moved + (1 - INERTIA_FORCE) * moved_past_escape);
 696                             }
 697                         }
 698
 699                     } else {
 700
 701                         // Calculate angle cosine of this vector-to-guide and all past vectors
 702                         // summed, to detect if we accidentally flipped to the other side of the
 703                         // guide
 704                         Geom::Point hatch_vector_accumulated = std::accumulate
 705                             (dc->hatch_vectors.begin(), dc->hatch_vectors.end(), Geom::Point(0,0));
 706                         double dot = Geom::dot (pointer - nearest, hatch_vector_accumulated);
 707                         dot /= Geom::L2(pointer - nearest) * Geom::L2(hatch_vector_accumulated);
 708
 709                         if (dc->hatch_spacing != 0) { // spacing was already set
 710                             double target;
 711                             if (speed > SPEED_NORMAL) {
 712                                 // all ok, strictly obey the spacing
 713                                 target = dc->hatch_spacing;
 714                             } else {
 715                                 // looks like we're starting to lose speed,
 716                                 // so _gradually_ let go attraction to prevent jerks
 717                                 target = (dc->hatch_spacing * speed + hatch_dist * (SPEED_NORMAL - speed))/SPEED_NORMAL;
 718                             }
 719                             if (!IS_NAN(dot) && dot < -0.5) {// flip
 720                                 target = -target;
 721                             }
 722
 723                             // This is the track pointer that we will use instead of the real one
 724                             Geom::Point new_pointer = nearest + target * hatch_unit_vector;
 725
 726                             // some limited feedback: allow persistent pulling to slightly change
 727                             // the spacing
 728                             dc->hatch_spacing += (hatch_dist - dc->hatch_spacing)/3500;
 729
 730                             // return it to the desktop coords
 731                             motion_dt = new_pointer * motion_to_curve.inverse();
 732
 733                             if (speed >= SPEED_NORMAL) {
 734                                 dc->inertia_vectors.push_front(motion_dt);
 735                                 if (dc->inertia_vectors.size() > INERTIA_ELEMENTS)
 736                                     dc->inertia_vectors.pop_back();
 737                             }
 738
 739                         } else {
 740                             // this is the first motion event, set the dist
 741                             dc->hatch_spacing = hatch_dist;
 742                         }
 743
 744                         // remember last points
 745                         dc->hatch_last_pointer = pointer;
 746                         dc->hatch_last_nearest = nearest;
 747
 748                         dc->hatch_vectors.push_front(pointer - nearest);
 749                         if (dc->hatch_vectors.size() > HATCH_VECTOR_ELEMENTS)
 750                             dc->hatch_vectors.pop_back();
 751                     }
 752
 753                     dc->_message_context->set(Inkscape::NORMAL_MESSAGE, dc->hatch_escaped? _("Tracking: <b>connection to guide path lost!</b>") : _("<b>Tracking</b> a guide path"));
 754
 755                 } else {
 756                     dc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("<b>Drawing</b> a calligraphic stroke"));
 757                 }
 758
 759                 if (dc->just_started_drawing) {
 760                     dc->just_started_drawing = false;
 761                     sp_dyna_draw_reset(dc, motion_dt);
 762                 }
 763
 764                 if (!sp_dyna_draw_apply(dc, motion_dt)) {
 765                     ret = TRUE;
 766                     break;
 767                 }
 768
 769                 if ( dc->cur != dc->last ) {
 770                     sp_dyna_draw_brush(dc);
 771                     g_assert( dc->npoints > 0 );
 772                     fit_and_split(dc, FALSE);
 773                 }
 774                 ret = TRUE;
 775             }
 776
 777             // Draw the hatching circle if necessary
 778             if (event->motion.state & GDK_CONTROL_MASK) {
 779                 if (dc->hatch_spacing == 0 && hatch_dist != 0) {
 780                     // Haven't set spacing yet: gray, center free, update radius live
 781                     Geom::Point c = desktop->w2d(motion_w);
 782                     Geom::Matrix const sm (Geom::Scale(hatch_dist, hatch_dist) * Geom::Translate(c));
 783                     sp_canvas_item_affine_absolute(dc->hatch_area, sm);
 784                     sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(dc->hatch_area), 0x7f7f7fff, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 785                     sp_canvas_item_show(dc->hatch_area);
 786                 } else if (dc->dragging && !dc->hatch_escaped) {
 787                     // Tracking: green, center snapped, fixed radius
 788                     Geom::Point c = motion_dt;
 789                     Geom::Matrix const sm (Geom::Scale(dc->hatch_spacing, dc->hatch_spacing) * Geom::Translate(c));
 790                     sp_canvas_item_affine_absolute(dc->hatch_area, sm);
 791                     sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(dc->hatch_area), 0x00FF00ff, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 792                     sp_canvas_item_show(dc->hatch_area);
 793                 } else if (dc->dragging && dc->hatch_escaped) {
 794                     // Tracking escaped: red, center free, fixed radius
 795                     Geom::Point c = motion_dt;
 796                     Geom::Matrix const sm (Geom::Scale(dc->hatch_spacing, dc->hatch_spacing) * Geom::Translate(c));
 797
 798                     sp_canvas_item_affine_absolute(dc->hatch_area, sm);
 799                     sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(dc->hatch_area), 0xFF0000ff, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 800                     sp_canvas_item_show(dc->hatch_area);
 801                 } else {
 802                     // Not drawing but spacing set: gray, center snapped, fixed radius
 803                     Geom::Point c = (nearest + dc->hatch_spacing * hatch_unit_vector) * motion_to_curve.inverse();
 804                     if (!IS_NAN(c[Geom::X]) && !IS_NAN(c[Geom::Y])) {
 805                         Geom::Matrix const sm (Geom::Scale(dc->hatch_spacing, dc->hatch_spacing) * Geom::Translate(c));
 806                         sp_canvas_item_affine_absolute(dc->hatch_area, sm);
 807                         sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(dc->hatch_area), 0x7f7f7fff, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 808                         sp_canvas_item_show(dc->hatch_area);
 809                     }
 810                 }
 811             } else {
 812                 sp_canvas_item_hide(dc->hatch_area);
 813             }
 814         }
 815         break;
 816
 817
 818     case GDK_BUTTON_RELEASE:
 819     {
 820         Geom::Point const motion_w(event->button.x, event->button.y);
 821         Geom::Point const motion_dt(desktop->w2d(motion_w));
 822
 823         sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate), event->button.time);
 824         sp_canvas_end_forced_full_redraws(desktop->canvas);
 825         dc->is_drawing = false;
 826
 827         if (dc->dragging && event->button.button == 1 && !event_context->space_panning) {
 828             dc->dragging = FALSE;
 829
 830             sp_dyna_draw_apply(dc, motion_dt);
 831
 832             /* Remove all temporary line segments */
 833             while (dc->segments) {
 834                 gtk_object_destroy(GTK_OBJECT(dc->segments->data));
 835                 dc->segments = g_slist_remove(dc->segments, dc->segments->data);
 836             }
 837
 838             /* Create object */
 839             fit_and_split(dc, TRUE);
 840             if (accumulate_calligraphic(dc))
 841                 set_to_accumulated(dc, event->button.state & GDK_SHIFT_MASK, event->button.state & GDK_MOD1_MASK); // performs document_done
 842             else
 843                 g_warning ("Failed to create path: invalid data in dc->cal1 or dc->cal2");
 844
 845             /* reset accumulated curve */
 846             dc->accumulated->reset();
 847
 848             clear_current(dc);
 849             if (dc->repr) {
 850                 dc->repr = NULL;
 851             }
 852
 853             if (!dc->hatch_pointer_past.empty()) dc->hatch_pointer_past.clear();
 854             if (!dc->hatch_nearest_past.empty()) dc->hatch_nearest_past.clear();
 855             if (!dc->inertia_vectors.empty()) dc->inertia_vectors.clear();
 856             if (!dc->hatch_vectors.empty()) dc->hatch_vectors.clear();
 857             dc->hatch_last_nearest = Geom::Point(0,0);
 858             dc->hatch_last_pointer = Geom::Point(0,0);
 859             dc->hatch_escaped = false;
 860             dc->hatch_item = NULL;
 861             dc->hatch_livarot_path = NULL;
 862             dc->just_started_drawing = false;
 863
 864             if (dc->hatch_spacing != 0 && !dc->keep_selected) {
 865                 // we do not select the newly drawn path, so increase spacing by step
 866                 if (dc->hatch_spacing_step == 0) {
 867                     dc->hatch_spacing_step = dc->hatch_spacing;
 868                 }
 869                 dc->hatch_spacing += dc->hatch_spacing_step;
 870             }
 871
 872             dc->_message_context->clear();
 873             ret = TRUE;
 874         }
 875         break;
 876     }
 877
 878     case GDK_KEY_PRESS:
 879         switch (get_group0_keyval (&event->key)) {
 880         case GDK_Up:
 881         case GDK_KP_Up:
 882             if (!MOD__CTRL_ONLY) {
 883                 dc->angle += 5.0;
 884                 if (dc->angle > 90.0)
 885                     dc->angle = 90.0;
 886                 sp_ddc_update_toolbox (desktop, "calligraphy-angle", dc->angle);
 887                 ret = TRUE;
 888             }
 889             break;
 890         case GDK_Down:
 891         case GDK_KP_Down:
 892             if (!MOD__CTRL_ONLY) {
 893                 dc->angle -= 5.0;
 894                 if (dc->angle < -90.0)
 895                     dc->angle = -90.0;
 896                 sp_ddc_update_toolbox (desktop, "calligraphy-angle", dc->angle);
 897                 ret = TRUE;
 898             }
 899             break;
 900         case GDK_Right:
 901         case GDK_KP_Right:
 902             if (!MOD__CTRL_ONLY) {
 903                 dc->width += 0.01;
 904                 if (dc->width > 1.0)
 905                     dc->width = 1.0;
 906                 sp_ddc_update_toolbox (desktop, "altx-calligraphy", dc->width * 100); // the same spinbutton is for alt+x
 907                 ret = TRUE;
 908             }
 909             break;
 910         case GDK_Left:
 911         case GDK_KP_Left:
 912             if (!MOD__CTRL_ONLY) {
 913                 dc->width -= 0.01;
 914                 if (dc->width < 0.01)
 915                     dc->width = 0.01;
 916                 sp_ddc_update_toolbox (desktop, "altx-calligraphy", dc->width * 100);
 917                 ret = TRUE;
 918             }
 919             break;
 920         case GDK_Home:
 921         case GDK_KP_Home:
 922             dc->width = 0.01;
 923             sp_ddc_update_toolbox (desktop, "altx-calligraphy", dc->width * 100);
 924             ret = TRUE;
 925             break;
 926         case GDK_End:
 927         case GDK_KP_End:
 928             dc->width = 1.0;
 929             sp_ddc_update_toolbox (desktop, "altx-calligraphy", dc->width * 100);
 930             ret = TRUE;
 931             break;
 932         case GDK_x:
 933         case GDK_X:
 934             if (MOD__ALT_ONLY) {
 935                 desktop->setToolboxFocusTo ("altx-calligraphy");
 936                 ret = TRUE;
 937             }
 938             break;
 939         case GDK_Escape:
 940             if (dc->is_drawing) {
 941                 // if drawing, cancel, otherwise pass it up for deselecting
 942                 calligraphic_cancel (dc);
 943                 ret = TRUE;
 944             }
 945             break;
 946         case GDK_z:
 947         case GDK_Z:
 948             if (MOD__CTRL_ONLY && dc->is_drawing) {
 949                 // if drawing, cancel, otherwise pass it up for undo
 950                 calligraphic_cancel (dc);
 951                 ret = TRUE;
 952             }
 953             break;
 954         default:
 955             break;
 956         }
 957         break;
 958
 959     case GDK_KEY_RELEASE:
 960         switch (get_group0_keyval(&event->key)) {
 961             case GDK_Control_L:
 962             case GDK_Control_R:
 963                 dc->_message_context->clear();
 964                 dc->hatch_spacing = 0;
 965                 dc->hatch_spacing_step = 0;
 966                 break;
 967             default:
 968                 break;
 969         }
 970
 971     default:
 972         break;
 973     }
 974
 975     if (!ret) {
 976         if (((SPEventContextClass *) dd_parent_class)->root_handler) {
 977             ret = ((SPEventContextClass *) dd_parent_class)->root_handler(event_context, event);
 978         }
 979     }
 980
 981     return ret;
 982 }
 983
 984
 985 static void
 986 clear_current(SPDynaDrawContext *dc)
 987 {
 988     /* reset bpath */
 989     sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(dc->currentshape), NULL);
 990     /* reset curve */
 991     dc->currentcurve->reset();
 992     dc->cal1->reset();
 993     dc->cal2->reset();
 994     /* reset points */
 995     dc->npoints = 0;
 996 }
 997
 998 static void
 999 set_to_accumulated(SPDynaDrawContext *dc, bool unionize, bool subtract)
1000 {
1001     SPDesktop *desktop = SP_EVENT_CONTEXT(dc)->desktop;
1002
1003     if (!dc->accumulated->is_empty()) {
1004         if (!dc->repr) {
1005             /* Create object */
1006             Inkscape::XML::Document *xml_doc = desktop->doc()->getReprDoc();
1007             Inkscape::XML::Node *repr = xml_doc->createElement("svg:path");
1008
1009             /* Set style */
1010             sp_desktop_apply_style_tool (desktop, repr, "/tools/calligraphic", false);
1011
1012             dc->repr = repr;
1013
1014             SPItem *item=SP_ITEM(desktop->currentLayer()->appendChildRepr(dc->repr));
1015             Inkscape::GC::release(dc->repr);
1016             item->transform = SP_ITEM(desktop->currentLayer())->i2doc_affine().inverse();
1017             item->updateRepr();
1018         }
1019         Geom::PathVector pathv = dc->accumulated->get_pathvector() * desktop->dt2doc();
1020         gchar *str = sp_svg_write_path(pathv);
1021         g_assert( str != NULL );
1022         dc->repr->setAttribute("d", str);
1023         g_free(str);
1024
1025         if (unionize) {
1026             sp_desktop_selection(desktop)->add(dc->repr);
1027             sp_selected_path_union_skip_undo(desktop);
1028         } else if (subtract) {
1029             sp_desktop_selection(desktop)->add(dc->repr);
1030             sp_selected_path_diff_skip_undo(desktop);
1031         } else {
1032             if (dc->keep_selected) {
1033                 sp_desktop_selection(desktop)->set(dc->repr);
1034             }
1035         }
1036
1037     } else {
1038         if (dc->repr) {
1039             sp_repr_unparent(dc->repr);
1040         }
1041         dc->repr = NULL;
1042     }
1043
1044     DocumentUndo::done(sp_desktop_document(desktop), SP_VERB_CONTEXT_CALLIGRAPHIC,
1045                        _("Draw calligraphic stroke"));
1046 }
1047
1048 static void
1049 add_cap(SPCurve *curve,
1050         Geom::Point const &from,
1051         Geom::Point const &to,
1052         double rounding)
1053 {
1054     if (Geom::L2( to - from ) > DYNA_EPSILON) {
1055         Geom::Point vel = rounding * Geom::rot90( to - from ) / sqrt(2.0);
1056         double mag = Geom::L2(vel);
1057
1058         Geom::Point v = mag * Geom::rot90( to - from ) / Geom::L2( to - from );
1059         curve->curveto(from + v, to + v, to);
1060     }
1061 }
1062
1063 static bool
1064 accumulate_calligraphic(SPDynaDrawContext *dc)
1065 {
1066         if (
1067             dc->cal1->is_empty() ||
1068             dc->cal2->is_empty() ||
1069             (dc->cal1->get_segment_count() <= 0) ||
1070             dc->cal1->first_path()->closed()
1071             ) {
1072             dc->cal1->reset();
1073             dc->cal2->reset();
1074             return false; // failure
1075         }
1076
1077         SPCurve *rev_cal2 = dc->cal2->create_reverse();
1078         if (
1079             (rev_cal2->get_segment_count() <= 0) ||
1080             rev_cal2->first_path()->closed()
1081             ) {
1082             rev_cal2->unref();
1083             dc->cal1->reset();
1084             dc->cal2->reset();
1085             return false; // failure
1086         }
1087
1088         Geom::CubicBezier const * dc_cal1_firstseg  = dynamic_cast<Geom::CubicBezier const *>( dc->cal1->first_segment() );
1089         Geom::CubicBezier const * rev_cal2_firstseg = dynamic_cast<Geom::CubicBezier const *>( rev_cal2->first_segment() );
1090         Geom::CubicBezier const * dc_cal1_lastseg   = dynamic_cast<Geom::CubicBezier const *>( dc->cal1->last_segment() );
1091         Geom::CubicBezier const * rev_cal2_lastseg  = dynamic_cast<Geom::CubicBezier const *>( rev_cal2->last_segment() );
1092
1093         if (
1094             !dc_cal1_firstseg ||
1095             !rev_cal2_firstseg ||
1096             !dc_cal1_lastseg ||
1097             !rev_cal2_lastseg
1098             ) {
1099             rev_cal2->unref();
1100             dc->cal1->reset();
1101             dc->cal2->reset();
1102             return false; // failure
1103         }
1104
1105         dc->accumulated->reset(); /*  Is this required ?? */
1106
1107         dc->accumulated->append(dc->cal1, false);
1108
1109         add_cap(dc->accumulated, (*dc_cal1_lastseg)[3], (*rev_cal2_firstseg)[0], dc->cap_rounding);
1110
1111         dc->accumulated->append(rev_cal2, true);
1112
1113         add_cap(dc->accumulated, (*rev_cal2_lastseg)[3], (*dc_cal1_firstseg)[0], dc->cap_rounding);
1114
1115         dc->accumulated->closepath();
1116
1117         rev_cal2->unref();
1118
1119         dc->cal1->reset();
1120         dc->cal2->reset();
1121
1122         return true; // success
1123 }
1124
1125 static double square(double const x)
1126 {
1127     return x * x;
1128 }
1129
1130 static void
1131 fit_and_split(SPDynaDrawContext *dc, gboolean release)
1132 {
1133     SPDesktop *desktop = SP_EVENT_CONTEXT(dc)->desktop;
1134
1135     double const tolerance_sq = square( desktop->w2d().descrim() * TOLERANCE_CALLIGRAPHIC );
1136
1137 #ifdef DYNA_DRAW_VERBOSE
1138     g_print("[F&S:R=%c]", release?'T':'F');
1139 #endif
1140
1141     if (!( dc->npoints > 0 && dc->npoints < SAMPLING_SIZE ))
1142         return; // just clicked
1143
1144     if ( dc->npoints == SAMPLING_SIZE - 1 || release ) {
1145 #define BEZIER_SIZE       4
1146 #define BEZIER_MAX_BEZIERS  8
1147 #define BEZIER_MAX_LENGTH ( BEZIER_SIZE * BEZIER_MAX_BEZIERS )
1148
1149 #ifdef DYNA_DRAW_VERBOSE
1150         g_print("[F&S:#] dc->npoints:%d, release:%s\n",
1151                 dc->npoints, release ? "TRUE" : "FALSE");
1152 #endif
1153
1154         /* Current calligraphic */
1155         if ( dc->cal1->is_empty() || dc->cal2->is_empty() ) {
1156             /* dc->npoints > 0 */
1157             /* g_print("calligraphics(1|2) reset\n"); */
1158             dc->cal1->reset();
1159             dc->cal2->reset();
1160
1161             dc->cal1->moveto(dc->point1[0]);
1162             dc->cal2->moveto(dc->point2[0]);
1163         }
1164
1165         Geom::Point b1[BEZIER_MAX_LENGTH];
1166         gint const nb1 = Geom::bezier_fit_cubic_r(b1, dc->point1, dc->npoints,
1167                                                tolerance_sq, BEZIER_MAX_BEZIERS);
1168         g_assert( nb1 * BEZIER_SIZE <= gint(G_N_ELEMENTS(b1)) );
1169
1170         Geom::Point b2[BEZIER_MAX_LENGTH];
1171         gint const nb2 = Geom::bezier_fit_cubic_r(b2, dc->point2, dc->npoints,
1172                                                tolerance_sq, BEZIER_MAX_BEZIERS);
1173         g_assert( nb2 * BEZIER_SIZE <= gint(G_N_ELEMENTS(b2)) );
1174
1175         if ( nb1 != -1 && nb2 != -1 ) {
1176             /* Fit and draw and reset state */
1177 #ifdef DYNA_DRAW_VERBOSE
1178             g_print("nb1:%d nb2:%d\n", nb1, nb2);
1179 #endif
1180             /* CanvasShape */
1181             if (! release) {
1182                 dc->currentcurve->reset();
1183                 dc->currentcurve->moveto(b1[0]);
1184                 for (Geom::Point *bp1 = b1; bp1 < b1 + BEZIER_SIZE * nb1; bp1 += BEZIER_SIZE) {
1185                     dc->currentcurve->curveto(bp1[1], bp1[2], bp1[3]);
1186                 }
1187                 dc->currentcurve->lineto(b2[BEZIER_SIZE*(nb2-1) + 3]);
1188                 for (Geom::Point *bp2 = b2 + BEZIER_SIZE * ( nb2 - 1 ); bp2 >= b2; bp2 -= BEZIER_SIZE) {
1189                     dc->currentcurve->curveto(bp2[2], bp2[1], bp2[0]);
1190                 }
1191                 // FIXME: dc->segments is always NULL at this point??
1192                 if (!dc->segments) { // first segment
1193                     add_cap(dc->currentcurve, b2[0], b1[0], dc->cap_rounding);
1194                 }
1195                 dc->currentcurve->closepath();
1196                 sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(dc->currentshape), dc->currentcurve);
1197             }
1198
1199             /* Current calligraphic */
1200             for (Geom::Point *bp1 = b1; bp1 < b1 + BEZIER_SIZE * nb1; bp1 += BEZIER_SIZE) {
1201                 dc->cal1->curveto(bp1[1], bp1[2], bp1[3]);
1202             }
1203             for (Geom::Point *bp2 = b2; bp2 < b2 + BEZIER_SIZE * nb2; bp2 += BEZIER_SIZE) {
1204                 dc->cal2->curveto(bp2[1], bp2[2], bp2[3]);
1205             }
1206         } else {
1207             /* fixme: ??? */
1208 #ifdef DYNA_DRAW_VERBOSE
1209             g_print("[fit_and_split] failed to fit-cubic.\n");
1210 #endif
1211             draw_temporary_box(dc);
1212
1213             for (gint i = 1; i < dc->npoints; i++) {
1214                 dc->cal1->lineto(dc->point1[i]);
1215             }
1216             for (gint i = 1; i < dc->npoints; i++) {
1217                 dc->cal2->lineto(dc->point2[i]);
1218             }
1219         }
1220
1221         /* Fit and draw and copy last point */
1222 #ifdef DYNA_DRAW_VERBOSE
1223         g_print("[%d]Yup\n", dc->npoints);
1224 #endif
1225         if (!release) {
1226             g_assert(!dc->currentcurve->is_empty());
1227
1228             SPCanvasItem *cbp = sp_canvas_item_new(sp_desktop_sketch(desktop),
1229                                                    SP_TYPE_CANVAS_BPATH,
1230                                                    NULL);
1231             SPCurve *curve = dc->currentcurve->copy();
1232             sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH (cbp), curve);
1233             curve->unref();
1234
1235             guint32 fillColor = sp_desktop_get_color_tool (desktop, "/tools/calligraphic", true);
1236             //guint32 strokeColor = sp_desktop_get_color_tool (desktop, "/tools/calligraphic", false);
1237             double opacity = sp_desktop_get_master_opacity_tool (desktop, "/tools/calligraphic");
1238             double fillOpacity = sp_desktop_get_opacity_tool (desktop, "/tools/calligraphic", true);
1239             //double strokeOpacity = sp_desktop_get_opacity_tool (desktop, "/tools/calligraphic", false);
1240             sp_canvas_bpath_set_fill(SP_CANVAS_BPATH(cbp), ((fillColor & 0xffffff00) | SP_COLOR_F_TO_U(opacity*fillOpacity)), SP_WIND_RULE_EVENODD);
1241             //on second thougtht don't do stroke yet because we don't have stoke-width yet and because stoke appears between segments while drawing
1242             //sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(cbp), ((strokeColor & 0xffffff00) | SP_COLOR_F_TO_U(opacity*strokeOpacity)), 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
1243             sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(cbp), 0x00000000, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
1244             /* fixme: Cannot we cascade it to root more clearly? */
1245             g_signal_connect(G_OBJECT(cbp), "event", G_CALLBACK(sp_desktop_root_handler), desktop);
1246
1247             dc->segments = g_slist_prepend(dc->segments, cbp);
1248         }
1249
1250         dc->point1[0] = dc->point1[dc->npoints - 1];
1251         dc->point2[0] = dc->point2[dc->npoints - 1];
1252         dc->npoints = 1;
1253     } else {
1254         draw_temporary_box(dc);
1255     }
1256 }
1257
1258 static void
1259 draw_temporary_box(SPDynaDrawContext *dc)
1260 {
1261     dc->currentcurve->reset();
1262
1263     dc->currentcurve->moveto(dc->point2[dc->npoints-1]);
1264     for (gint i = dc->npoints-2; i >= 0; i--) {
1265         dc->currentcurve->lineto(dc->point2[i]);
1266     }
1267     for (gint i = 0; i < dc->npoints; i++) {
1268         dc->currentcurve->lineto(dc->point1[i]);
1269     }
1270
1271     if (dc->npoints >= 2) {
1272         add_cap(dc->currentcurve, dc->point1[dc->npoints-1], dc->point2[dc->npoints-1], dc->cap_rounding);
1273     }
1274
1275     dc->currentcurve->closepath();
1276     sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(dc->currentshape), dc->currentcurve);
1277 }
1278
1279 /*
1280   Local Variables:
1281   mode:c++
1282   c-file-style:"stroustrup"
1283   c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
1284   indent-tabs-mode:nil
1285   fill-column:99
1286   End:
1287 */
1288 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :