src/dyna-draw-context.cpp

   1 #define __SP_DYNA_DRAW_CONTEXT_C__
   2
   3 /*
   4  * Handwriting-like drawing mode
   5  *
   6  * Authors:
   7  *   Mitsuru Oka <oka326@parkcity.ne.jp>
   8  *   Lauris Kaplinski <lauris@kaplinski.com>
   9  *   bulia byak <buliabyak@users.sf.net>
  10  *   MenTaLguY <mental@rydia.net>
  11  *
  12  * The original dynadraw code:
  13  *   Paul Haeberli <paul@sgi.com>
  14  *
  15  * Copyright (C) 1998 The Free Software Foundation
  16  * Copyright (C) 1999-2005 authors
  17  * Copyright (C) 2001-2002 Ximian, Inc.
  18  * Copyright (C) 2005-2007 bulia byak
  19  * Copyright (C) 2006 MenTaLguY
  20  *
  21  * Released under GNU GPL, read the file 'COPYING' for more information
  22  */
  23
  24 #define noDYNA_DRAW_VERBOSE
  25
  26 #include "config.h"
  27
  28 #include <gtk/gtk.h>
  29 #include <gdk/gdkkeysyms.h>
  30 #include <glibmm/i18n.h>
  31 #include <string>
  32 #include <cstring>
  33 #include <numeric>
  34
  35 #include "svg/svg.h"
  36 #include "display/canvas-bpath.h"
  37 #include <2geom/isnan.h>
  38 #include <2geom/pathvector.h>
  39 #include <2geom/bezier-utils.h>
  40 #include "display/curve.h"
  41 #include <glib/gmem.h>
  42 #include "macros.h"
  43 #include "document.h"
  44 #include "selection.h"
  45 #include "desktop.h"
  46 #include "desktop-events.h"
  47 #include "desktop-handles.h"
  48 #include "desktop-style.h"
  49 #include "message-context.h"
  50 #include "preferences.h"
  51 #include "pixmaps/cursor-calligraphy.xpm"
  52 #include "xml/repr.h"
  53 #include "context-fns.h"
  54 #include "sp-item.h"
  55 #include "inkscape.h"
  56 #include "color.h"
  57 #include "splivarot.h"
  58 #include "sp-item-group.h"
  59 #include "sp-shape.h"
  60 #include "sp-path.h"
  61 #include "sp-text.h"
  62 #include "display/canvas-bpath.h"
  63 #include "display/canvas-arena.h"
  64 #include "livarot/Shape.h"
  65
  66 #include "dyna-draw-context.h"
  67
  68 #define DDC_RED_RGBA 0xff0000ff
  69
  70 #define TOLERANCE_CALLIGRAPHIC 0.1
  71
  72 #define DYNA_EPSILON 0.5e-6
  73 #define DYNA_EPSILON_START 0.5e-2
  74 #define DYNA_VEL_START 1e-5
  75
  76 #define DYNA_MIN_WIDTH 1.0e-6
  77
  78 static void sp_dyna_draw_context_class_init(SPDynaDrawContextClass *klass);
  79 static void sp_dyna_draw_context_init(SPDynaDrawContext *ddc);
  80 static void sp_dyna_draw_context_dispose(GObject *object);
  81
  82 static void sp_dyna_draw_context_setup(SPEventContext *ec);
  83 static void sp_dyna_draw_context_set(SPEventContext *ec, Inkscape::Preferences::Entry *value);
  84 static gint sp_dyna_draw_context_root_handler(SPEventContext *ec, GdkEvent *event);
  85
  86 static void clear_current(SPDynaDrawContext *dc);
  87 static void set_to_accumulated(SPDynaDrawContext *dc, bool unionize, bool subtract);
  88 static void add_cap(SPCurve *curve, Geom::Point const &from, Geom::Point const &to, double rounding);
  89 static bool accumulate_calligraphic(SPDynaDrawContext *dc);
  90
  91 static void fit_and_split(SPDynaDrawContext *ddc, gboolean release);
  92
  93 static void sp_dyna_draw_reset(SPDynaDrawContext *ddc, Geom::Point p);
  94 static Geom::Point sp_dyna_draw_get_npoint(SPDynaDrawContext const *ddc, Geom::Point v);
  95 static Geom::Point sp_dyna_draw_get_vpoint(SPDynaDrawContext const *ddc, Geom::Point n);
  96 static void draw_temporary_box(SPDynaDrawContext *dc);
  97
  98
  99 static SPEventContextClass *dd_parent_class = 0;
 100
 101 GType sp_dyna_draw_context_get_type(void)
 102 {
 103     static GType type = 0;
 104     if (!type) {
 105         GTypeInfo info = {
 106             sizeof(SPDynaDrawContextClass),
 107             0, // base_init
 108             0, // base_finalize
 109             (GClassInitFunc)sp_dyna_draw_context_class_init,
 110             0, // class_finalize
 111             0, // class_data
 112             sizeof(SPDynaDrawContext),
 113             0, // n_preallocs
 114             (GInstanceInitFunc)sp_dyna_draw_context_init,
 115             0 // value_table
 116         };
 117         type = g_type_register_static(SP_TYPE_COMMON_CONTEXT, "SPDynaDrawContext", &info, static_cast<GTypeFlags>(0));
 118     }
 119     return type;
 120 }
 121
 122 static void
 123 sp_dyna_draw_context_class_init(SPDynaDrawContextClass *klass)
 124 {
 125     GObjectClass *object_class = (GObjectClass *) klass;
 126     SPEventContextClass *event_context_class = (SPEventContextClass *) klass;
 127
 128     dd_parent_class = (SPEventContextClass*)g_type_class_peek_parent(klass);
 129
 130     object_class->dispose = sp_dyna_draw_context_dispose;
 131
 132     event_context_class->setup = sp_dyna_draw_context_setup;
 133     event_context_class->set = sp_dyna_draw_context_set;
 134     event_context_class->root_handler = sp_dyna_draw_context_root_handler;
 135 }
 136
 137 static void
 138 sp_dyna_draw_context_init(SPDynaDrawContext *ddc)
 139 {
 140     ddc->cursor_shape = cursor_calligraphy_xpm;
 141     ddc->hot_x = 4;
 142     ddc->hot_y = 4;
 143
 144     ddc->vel_thin = 0.1;
 145     ddc->flatness = 0.9;
 146     ddc->cap_rounding = 0.0;
 147
 148     ddc->abs_width = false;
 149     ddc->keep_selected = true;
 150
 151     ddc->hatch_spacing = 0;
 152     ddc->hatch_spacing_step = 0;
 153     new (&ddc->hatch_pointer_past) std::list<double>();
 154     new (&ddc->hatch_nearest_past) std::list<double>();
 155     new (&ddc->inertia_vectors) std::list<Geom::Point>();
 156     new (&ddc->hatch_vectors) std::list<Geom::Point>();
 157     ddc->hatch_last_nearest = Geom::Point(0,0);
 158     ddc->hatch_last_pointer = Geom::Point(0,0);
 159     ddc->hatch_escaped = false;
 160     ddc->hatch_area = NULL;
 161     ddc->hatch_item = NULL;
 162     ddc->hatch_livarot_path = NULL;
 163
 164     ddc->trace_bg = false;
 165     ddc->just_started_drawing = false;
 166 }
 167
 168 static void
 169 sp_dyna_draw_context_dispose(GObject *object)
 170 {
 171     SPDynaDrawContext *ddc = SP_DYNA_DRAW_CONTEXT(object);
 172
 173     if (ddc->hatch_area) {
 174         gtk_object_destroy(GTK_OBJECT(ddc->hatch_area));
 175         ddc->hatch_area = NULL;
 176     }
 177
 178
 179     G_OBJECT_CLASS(dd_parent_class)->dispose(object);
 180
 181     ddc->hatch_pointer_past.~list();
 182     ddc->hatch_nearest_past.~list();
 183     ddc->inertia_vectors.~list();
 184     ddc->hatch_vectors.~list();
 185 }
 186
 187 static void
 188 sp_dyna_draw_context_setup(SPEventContext *ec)
 189 {
 190     SPDynaDrawContext *ddc = SP_DYNA_DRAW_CONTEXT(ec);
 191
 192     if (((SPEventContextClass *) dd_parent_class)->setup)
 193         ((SPEventContextClass *) dd_parent_class)->setup(ec);
 194
 195     ddc->accumulated = new SPCurve();
 196     ddc->currentcurve = new SPCurve();
 197
 198     ddc->cal1 = new SPCurve();
 199     ddc->cal2 = new SPCurve();
 200
 201     ddc->currentshape = sp_canvas_item_new(sp_desktop_sketch(ec->desktop), SP_TYPE_CANVAS_BPATH, NULL);
 202     sp_canvas_bpath_set_fill(SP_CANVAS_BPATH(ddc->currentshape), DDC_RED_RGBA, SP_WIND_RULE_EVENODD);
 203     sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(ddc->currentshape), 0x00000000, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 204     /* fixme: Cannot we cascade it to root more clearly? */
 205     g_signal_connect(G_OBJECT(ddc->currentshape), "event", G_CALLBACK(sp_desktop_root_handler), ec->desktop);
 206
 207     {
 208         /* 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) */
 209         SPCurve *c = new SPCurve();
 210         const double C1 = 0.552;
 211         c->moveto(-1,0);
 212         c->curveto(-1, C1, -C1, 1, 0, 1 );
 213         c->curveto(C1, 1, 1, C1, 1, 0 );
 214         c->curveto(1, -C1, C1, -1, 0, -1 );
 215         c->curveto(-C1, -1, -1, -C1, -1, 0 );
 216         c->closepath();
 217         ddc->hatch_area = sp_canvas_bpath_new(sp_desktop_controls(ec->desktop), c);
 218         c->unref();
 219         sp_canvas_bpath_set_fill(SP_CANVAS_BPATH(ddc->hatch_area), 0x00000000,(SPWindRule)0);
 220         sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(ddc->hatch_area), 0x0000007f, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 221         sp_canvas_item_hide(ddc->hatch_area);
 222     }
 223
 224     sp_event_context_read(ec, "mass");
 225     sp_event_context_read(ec, "wiggle");
 226     sp_event_context_read(ec, "angle");
 227     sp_event_context_read(ec, "width");
 228     sp_event_context_read(ec, "thinning");
 229     sp_event_context_read(ec, "tremor");
 230     sp_event_context_read(ec, "flatness");
 231     sp_event_context_read(ec, "tracebackground");
 232     sp_event_context_read(ec, "usepressure");
 233     sp_event_context_read(ec, "usetilt");
 234     sp_event_context_read(ec, "abs_width");
 235     sp_event_context_read(ec, "keep_selected");
 236     sp_event_context_read(ec, "cap_rounding");
 237
 238     ddc->is_drawing = false;
 239     ddc->_message_context = new Inkscape::MessageContext((ec->desktop)->messageStack());
 240
 241     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 242     if (prefs->getBool("/tools/calligraphic/selcue")) {
 243         ec->enableSelectionCue();
 244     }
 245 }
 246
 247 static void
 248 sp_dyna_draw_context_set(SPEventContext *ec, Inkscape::Preferences::Entry *val)
 249 {
 250     SPDynaDrawContext *ddc = SP_DYNA_DRAW_CONTEXT(ec);
 251     Glib::ustring path = val->getEntryName();
 252
 253     if (path == "tracebackground") {
 254         ddc->trace_bg = val->getBool();
 255     } else if (path == "keep_selected") {
 256         ddc->keep_selected = val->getBool();
 257     } else {
 258         //pass on up to parent class to handle common attributes.
 259         if ( dd_parent_class->set ) {
 260             dd_parent_class->set(ec, val);
 261         }
 262     }
 263
 264     //g_print("DDC: %g %g %g %g\n", ddc->mass, ddc->drag, ddc->angle, ddc->width);
 265 }
 266
 267 static double
 268 flerp(double f0, double f1, double p)
 269 {
 270     return f0 + ( f1 - f0 ) * p;
 271 }
 272
 273 /* Get normalized point */
 274 static Geom::Point
 275 sp_dyna_draw_get_npoint(SPDynaDrawContext const *dc, Geom::Point v)
 276 {
 277     Geom::Rect drect = SP_EVENT_CONTEXT(dc)->desktop->get_display_area();
 278     double const max = MAX ( drect.dimensions()[Geom::X], drect.dimensions()[Geom::Y] );
 279     return Geom::Point(( v[Geom::X] - drect.min()[Geom::X] ) / max,  ( v[Geom::Y] - drect.min()[Geom::Y] ) / max);
 280 }
 281
 282 /* Get view point */
 283 static Geom::Point
 284 sp_dyna_draw_get_vpoint(SPDynaDrawContext const *dc, Geom::Point n)
 285 {
 286     Geom::Rect drect = SP_EVENT_CONTEXT(dc)->desktop->get_display_area();
 287     double const max = MAX ( drect.dimensions()[Geom::X], drect.dimensions()[Geom::Y] );
 288     return Geom::Point(n[Geom::X] * max + drect.min()[Geom::X], n[Geom::Y] * max + drect.min()[Geom::Y]);
 289 }
 290
 291 static void
 292 sp_dyna_draw_reset(SPDynaDrawContext *dc, Geom::Point p)
 293 {
 294     dc->last = dc->cur = sp_dyna_draw_get_npoint(dc, p);
 295     dc->vel = Geom::Point(0,0);
 296     dc->vel_max = 0;
 297     dc->acc = Geom::Point(0,0);
 298     dc->ang = Geom::Point(0,0);
 299     dc->del = Geom::Point(0,0);
 300 }
 301
 302 static void
 303 sp_dyna_draw_extinput(SPDynaDrawContext *dc, GdkEvent *event)
 304 {
 305     if (gdk_event_get_axis (event, GDK_AXIS_PRESSURE, &dc->pressure))
 306         dc->pressure = CLAMP (dc->pressure, DDC_MIN_PRESSURE, DDC_MAX_PRESSURE);
 307     else
 308         dc->pressure = DDC_DEFAULT_PRESSURE;
 309
 310     if (gdk_event_get_axis (event, GDK_AXIS_XTILT, &dc->xtilt))
 311         dc->xtilt = CLAMP (dc->xtilt, DDC_MIN_TILT, DDC_MAX_TILT);
 312     else
 313         dc->xtilt = DDC_DEFAULT_TILT;
 314
 315     if (gdk_event_get_axis (event, GDK_AXIS_YTILT, &dc->ytilt))
 316         dc->ytilt = CLAMP (dc->ytilt, DDC_MIN_TILT, DDC_MAX_TILT);
 317     else
 318         dc->ytilt = DDC_DEFAULT_TILT;
 319 }
 320
 321
 322 static gboolean
 323 sp_dyna_draw_apply(SPDynaDrawContext *dc, Geom::Point p)
 324 {
 325     Geom::Point n = sp_dyna_draw_get_npoint(dc, p);
 326
 327     /* Calculate mass and drag */
 328     double const mass = flerp(1.0, 160.0, dc->mass);
 329     double const drag = flerp(0.0, 0.5, dc->drag * dc->drag);
 330
 331     /* Calculate force and acceleration */
 332     Geom::Point force = n - dc->cur;
 333
 334     // If force is below the absolute threshold DYNA_EPSILON,
 335     // or we haven't yet reached DYNA_VEL_START (i.e. at the beginning of stroke)
 336     // _and_ the force is below the (higher) DYNA_EPSILON_START threshold,
 337     // discard this move.
 338     // This prevents flips, blobs, and jerks caused by microscopic tremor of the tablet pen,
 339     // especially bothersome at the start of the stroke where we don't yet have the inertia to
 340     // smooth them out.
 341     if ( Geom::L2(force) < DYNA_EPSILON || (dc->vel_max < DYNA_VEL_START && Geom::L2(force) < DYNA_EPSILON_START)) {
 342         return FALSE;
 343     }
 344
 345     dc->acc = force / mass;
 346
 347     /* Calculate new velocity */
 348     dc->vel += dc->acc;
 349
 350     if (Geom::L2(dc->vel) > dc->vel_max)
 351         dc->vel_max = Geom::L2(dc->vel);
 352
 353     /* Calculate angle of drawing tool */
 354
 355     double a1;
 356     if (dc->usetilt) {
 357         // 1a. calculate nib angle from input device tilt:
 358         gdouble length = std::sqrt(dc->xtilt*dc->xtilt + dc->ytilt*dc->ytilt);;
 359
 360         if (length > 0) {
 361             Geom::Point ang1 = Geom::Point(dc->ytilt/length, dc->xtilt/length);
 362             a1 = atan2(ang1);
 363         }
 364         else
 365             a1 = 0.0;
 366     }
 367     else {
 368         // 1b. fixed dc->angle (absolutely flat nib):
 369         double const radians = ( (dc->angle - 90) / 180.0 ) * M_PI;
 370         Geom::Point ang1 = Geom::Point(-sin(radians),  cos(radians));
 371         a1 = atan2(ang1);
 372     }
 373
 374     // 2. perpendicular to dc->vel (absolutely non-flat nib):
 375     gdouble const mag_vel = Geom::L2(dc->vel);
 376     if ( mag_vel < DYNA_EPSILON ) {
 377         return FALSE;
 378     }
 379     Geom::Point ang2 = Geom::rot90(dc->vel) / mag_vel;
 380
 381     // 3. Average them using flatness parameter:
 382     // calculate angles
 383     double a2 = atan2(ang2);
 384     // flip a2 to force it to be in the same half-circle as a1
 385     bool flipped = false;
 386     if (fabs (a2-a1) > 0.5*M_PI) {
 387         a2 += M_PI;
 388         flipped = true;
 389     }
 390     // normalize a2
 391     if (a2 > M_PI)
 392         a2 -= 2*M_PI;
 393     if (a2 < -M_PI)
 394         a2 += 2*M_PI;
 395     // find the flatness-weighted bisector angle, unflip if a2 was flipped
 396     // FIXME: when dc->vel is oscillating around the fixed angle, the new_ang flips back and forth. How to avoid this?
 397     double new_ang = a1 + (1 - dc->flatness) * (a2 - a1) - (flipped? M_PI : 0);
 398
 399     // Try to detect a sudden flip when the new angle differs too much from the previous for the
 400     // current velocity; in that case discard this move
 401     double angle_delta = Geom::L2(Geom::Point (cos (new_ang), sin (new_ang)) - dc->ang);
 402     if ( angle_delta / Geom::L2(dc->vel) > 4000 ) {
 403         return FALSE;
 404     }
 405
 406     // convert to point
 407     dc->ang = Geom::Point (cos (new_ang), sin (new_ang));
 408
 409 //    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);
 410
 411     /* Apply drag */
 412     dc->vel *= 1.0 - drag;
 413
 414     /* Update position */
 415     dc->last = dc->cur;
 416     dc->cur += dc->vel;
 417
 418     return TRUE;
 419 }
 420
 421 static void
 422 sp_dyna_draw_brush(SPDynaDrawContext *dc)
 423 {
 424     g_assert( dc->npoints >= 0 && dc->npoints < SAMPLING_SIZE );
 425
 426     // How much velocity thins strokestyle
 427     double vel_thin = flerp (0, 160, dc->vel_thin);
 428
 429     // Influence of pressure on thickness
 430     double pressure_thick = (dc->usepressure ? dc->pressure : 1.0);
 431
 432     // get the real brush point, not the same as pointer (affected by hatch tracking and/or mass
 433     // drag)
 434     Geom::Point brush = sp_dyna_draw_get_vpoint(dc, dc->cur);
 435     Geom::Point brush_w = SP_EVENT_CONTEXT(dc)->desktop->d2w(brush);
 436
 437     double trace_thick = 1;
 438     if (dc->trace_bg) {
 439         // pick single pixel
 440         NRPixBlock pb;
 441         int x = (int) floor(brush_w[Geom::X]);
 442         int y = (int) floor(brush_w[Geom::Y]);
 443         nr_pixblock_setup_fast(&pb, NR_PIXBLOCK_MODE_R8G8B8A8P, x, y, x+1, y+1, TRUE);
 444         sp_canvas_arena_render_pixblock(SP_CANVAS_ARENA(sp_desktop_drawing(SP_EVENT_CONTEXT(dc)->desktop)), &pb);
 445         const unsigned char *s = NR_PIXBLOCK_PX(&pb);
 446         double R = s[0] / 255.0;
 447         double G = s[1] / 255.0;
 448         double B = s[2] / 255.0;
 449         double A = s[3] / 255.0;
 450         double max = MAX (MAX (R, G), B);
 451         double min = MIN (MIN (R, G), B);
 452         double L = A * (max + min)/2 + (1 - A); // blend with white bg
 453         trace_thick = 1 - L;
 454         //g_print ("L %g thick %g\n", L, trace_thick);
 455     }
 456
 457     double width = (pressure_thick * trace_thick - vel_thin * Geom::L2(dc->vel)) * dc->width;
 458
 459     double tremble_left = 0, tremble_right = 0;
 460     if (dc->tremor > 0) {
 461         // obtain two normally distributed random variables, using polar Box-Muller transform
 462         double x1, x2, w, y1, y2;
 463         do {
 464             x1 = 2.0 * g_random_double_range(0,1) - 1.0;
 465             x2 = 2.0 * g_random_double_range(0,1) - 1.0;
 466             w = x1 * x1 + x2 * x2;
 467         } while ( w >= 1.0 );
 468         w = sqrt( (-2.0 * log( w ) ) / w );
 469         y1 = x1 * w;
 470         y2 = x2 * w;
 471
 472         // deflect both left and right edges randomly and independently, so that:
 473         // (1) dc->tremor=1 corresponds to sigma=1, decreasing dc->tremor narrows the bell curve;
 474         // (2) deflection depends on width, but is upped for small widths for better visual uniformity across widths;
 475         // (3) deflection somewhat depends on speed, to prevent fast strokes looking
 476         // comparatively smooth and slow ones excessively jittery
 477         tremble_left  = (y1)*dc->tremor * (0.15 + 0.8*width) * (0.35 + 14*Geom::L2(dc->vel));
 478         tremble_right = (y2)*dc->tremor * (0.15 + 0.8*width) * (0.35 + 14*Geom::L2(dc->vel));
 479     }
 480
 481     if ( width < 0.02 * dc->width ) {
 482         width = 0.02 * dc->width;
 483     }
 484
 485     double dezoomify_factor = 0.05 * 1000;
 486     if (!dc->abs_width) {
 487         dezoomify_factor /= SP_EVENT_CONTEXT(dc)->desktop->current_zoom();
 488     }
 489
 490     Geom::Point del_left = dezoomify_factor * (width + tremble_left) * dc->ang;
 491     Geom::Point del_right = dezoomify_factor * (width + tremble_right) * dc->ang;
 492
 493     dc->point1[dc->npoints] = brush + del_left;
 494     dc->point2[dc->npoints] = brush - del_right;
 495
 496     dc->del = 0.5*(del_left + del_right);
 497
 498     dc->npoints++;
 499 }
 500
 501 void
 502 sp_ddc_update_toolbox (SPDesktop *desktop, const gchar *id, double value)
 503 {
 504     desktop->setToolboxAdjustmentValue (id, value);
 505 }
 506
 507 static void
 508 calligraphic_cancel(SPDynaDrawContext *dc)
 509 {
 510     SPDesktop *desktop = SP_EVENT_CONTEXT(dc)->desktop;
 511     dc->dragging = FALSE;
 512     dc->is_drawing = false;
 513     sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate), 0);
 514             /* Remove all temporary line segments */
 515             while (dc->segments) {
 516                 gtk_object_destroy(GTK_OBJECT(dc->segments->data));
 517                 dc->segments = g_slist_remove(dc->segments, dc->segments->data);
 518             }
 519             /* reset accumulated curve */
 520             dc->accumulated->reset();
 521             clear_current(dc);
 522             if (dc->repr) {
 523                 dc->repr = NULL;
 524             }
 525 }
 526
 527
 528 gint
 529 sp_dyna_draw_context_root_handler(SPEventContext *event_context,
 530                                   GdkEvent *event)
 531 {
 532     SPDynaDrawContext *dc = SP_DYNA_DRAW_CONTEXT(event_context);
 533     SPDesktop *desktop = event_context->desktop;
 534
 535     gint ret = FALSE;
 536
 537     switch (event->type) {
 538         case GDK_BUTTON_PRESS:
 539             if (event->button.button == 1 && !event_context->space_panning) {
 540
 541                 SPDesktop *desktop = SP_EVENT_CONTEXT_DESKTOP(dc);
 542
 543                 if (Inkscape::have_viable_layer(desktop, dc->_message_context) == false) {
 544                     return TRUE;
 545                 }
 546
 547                 dc->accumulated->reset();
 548                 if (dc->repr) {
 549                     dc->repr = NULL;
 550                 }
 551
 552                 /* initialize first point */
 553                 dc->npoints = 0;
 554
 555                 sp_canvas_item_grab(SP_CANVAS_ITEM(desktop->acetate),
 556                                     ( GDK_KEY_PRESS_MASK |
 557                                       GDK_BUTTON_RELEASE_MASK |
 558                                       GDK_POINTER_MOTION_MASK |
 559                                       GDK_BUTTON_PRESS_MASK ),
 560                                     NULL,
 561                                     event->button.time);
 562
 563                 ret = TRUE;
 564
 565                 sp_canvas_force_full_redraw_after_interruptions(desktop->canvas, 3);
 566                 dc->is_drawing = true;
 567                 dc->just_started_drawing = true;
 568             }
 569             break;
 570         case GDK_MOTION_NOTIFY:
 571         {
 572             Geom::Point const motion_w(event->motion.x,
 573                                      event->motion.y);
 574             Geom::Point motion_dt(desktop->w2d(motion_w));
 575             sp_dyna_draw_extinput(dc, event);
 576
 577             dc->_message_context->clear();
 578
 579             // for hatching:
 580             double hatch_dist = 0;
 581             Geom::Point hatch_unit_vector(0,0);
 582             Geom::Point nearest(0,0);
 583             Geom::Point pointer(0,0);
 584             Geom::Matrix motion_to_curve(Geom::identity());
 585
 586             if (event->motion.state & GDK_CONTROL_MASK) { // hatching - sense the item
 587
 588                 SPItem *selected = sp_desktop_selection(desktop)->singleItem();
 589                 if (selected && (SP_IS_SHAPE(selected) || SP_IS_TEXT(selected))) {
 590                     // One item selected, and it's a path;
 591                     // let's try to track it as a guide
 592
 593                     if (selected != dc->hatch_item) {
 594                         dc->hatch_item = selected;
 595                         if (dc->hatch_livarot_path)
 596                             delete dc->hatch_livarot_path;
 597                         dc->hatch_livarot_path = Path_for_item (dc->hatch_item, true, true);
 598                         dc->hatch_livarot_path->ConvertWithBackData(0.01);
 599                     }
 600
 601                     // calculate pointer point in the guide item's coords
 602                     motion_to_curve = sp_item_dt2i_affine(selected) * sp_item_i2doc_affine(selected);
 603                     pointer = motion_dt * motion_to_curve;
 604
 605                     // calculate the nearest point on the guide path
 606                     boost::optional<Path::cut_position> position = get_nearest_position_on_Path(dc->hatch_livarot_path, pointer);
 607                     nearest = get_point_on_Path(dc->hatch_livarot_path, position->piece, position->t);
 608
 609
 610                     // distance from pointer to nearest
 611                     hatch_dist = Geom::L2(pointer - nearest);
 612                     // unit-length vector
 613                     hatch_unit_vector = (pointer - nearest)/hatch_dist;
 614
 615                     dc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("<b>Guide path selected</b>; start drawing along the guide with <b>Ctrl</b>"));
 616                 } else {
 617                     dc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("<b>Select a guide path</b> to track with <b>Ctrl</b>"));
 618                 }
 619             }
 620
 621             if ( dc->is_drawing && (event->motion.state & GDK_BUTTON1_MASK) && !event_context->space_panning) {
 622                 dc->dragging = TRUE;
 623
 624                 if (event->motion.state & GDK_CONTROL_MASK && dc->hatch_item) { // hatching
 625
 626 #define HATCH_VECTOR_ELEMENTS 12
 627 #define INERTIA_ELEMENTS 24
 628 #define SPEED_ELEMENTS 12
 629 #define SPEED_MIN 0.3
 630 #define SPEED_NORMAL 0.35
 631 #define INERTIA_FORCE 0.5
 632
 633                     // speed is the movement of the nearest point along the guide path, divided by
 634                     // the movement of the pointer at the same period; it is averaged for the last
 635                     // SPEED_ELEMENTS motion events.  Normally, as you track the guide path, speed
 636                     // is about 1, i.e. the nearest point on the path is moved by about the same
 637                     // distance as the pointer. If the speed starts to decrease, we are losing
 638                     // contact with the guide; if it drops below SPEED_MIN, we are on our own and
 639                     // not attracted to guide anymore. Most often this happens when you have
 640                     // tracked to the end of a guide calligraphic stroke and keep moving
 641                     // further. We try to handle this situation gracefully: not stick with the
 642                     // guide forever but let go of it smoothly and without sharp jerks (non-zero
 643                     // mass recommended; with zero mass, jerks are still quite noticeable).
 644
 645                     double speed = 1;
 646                     if (Geom::L2(dc->hatch_last_nearest) != 0) {
 647                         // the distance nearest moved since the last motion event
 648                         double nearest_moved = Geom::L2(nearest - dc->hatch_last_nearest);
 649                         // the distance pointer moved since the last motion event
 650                         double pointer_moved = Geom::L2(pointer - dc->hatch_last_pointer);
 651                         // store them in stacks limited to SPEED_ELEMENTS
 652                         dc->hatch_nearest_past.push_front(nearest_moved);
 653                         if (dc->hatch_nearest_past.size() > SPEED_ELEMENTS)
 654                             dc->hatch_nearest_past.pop_back();
 655                         dc->hatch_pointer_past.push_front(pointer_moved);
 656                         if (dc->hatch_pointer_past.size() > SPEED_ELEMENTS)
 657                             dc->hatch_pointer_past.pop_back();
 658
 659                         // If the stacks are full,
 660                         if (dc->hatch_nearest_past.size() == SPEED_ELEMENTS) {
 661                             // calculate the sums of all stored movements
 662                             double nearest_sum = std::accumulate (dc->hatch_nearest_past.begin(), dc->hatch_nearest_past.end(), 0.0);
 663                             double pointer_sum = std::accumulate (dc->hatch_pointer_past.begin(), dc->hatch_pointer_past.end(), 0.0);
 664                             // and divide to get the speed
 665                             speed = nearest_sum/pointer_sum;
 666                             //g_print ("nearest sum %g  pointer_sum %g  speed %g\n", nearest_sum, pointer_sum, speed);
 667                         }
 668                     }
 669
 670                     if (   dc->hatch_escaped  // already escaped, do not reattach
 671                         || (speed < SPEED_MIN) // stuck; most likely reached end of traced stroke
 672                         || (dc->hatch_spacing > 0 && hatch_dist > 50 * dc->hatch_spacing) // went too far from the guide
 673                         ) {
 674                         // We are NOT attracted to the guide!
 675
 676                         //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);
 677
 678                         // Remember hatch_escaped so we don't get
 679                         // attracted again until the end of this stroke
 680                         dc->hatch_escaped = true;
 681
 682                         if (dc->inertia_vectors.size() >= INERTIA_ELEMENTS/2) { // move by inertia
 683                             Geom::Point moved_past_escape = motion_dt - dc->inertia_vectors.front();
 684                             Geom::Point inertia =
 685                                 dc->inertia_vectors.front() - dc->inertia_vectors.back();
 686
 687                             double dot = Geom::dot (moved_past_escape, inertia);
 688                             dot /= Geom::L2(moved_past_escape) * Geom::L2(inertia);
 689
 690                             if (dot > 0) { // mouse is still moving in approx the same direction
 691                                 Geom::Point should_have_moved =
 692                                     (inertia) * (1/Geom::L2(inertia)) * Geom::L2(moved_past_escape);
 693                                 motion_dt = dc->inertia_vectors.front() +
 694                                     (INERTIA_FORCE * should_have_moved + (1 - INERTIA_FORCE) * moved_past_escape);
 695                             }
 696                         }
 697
 698                     } else {
 699
 700                         // Calculate angle cosine of this vector-to-guide and all past vectors
 701                         // summed, to detect if we accidentally flipped to the other side of the
 702                         // guide
 703                         Geom::Point hatch_vector_accumulated = std::accumulate
 704                             (dc->hatch_vectors.begin(), dc->hatch_vectors.end(), Geom::Point(0,0));
 705                         double dot = Geom::dot (pointer - nearest, hatch_vector_accumulated);
 706                         dot /= Geom::L2(pointer - nearest) * Geom::L2(hatch_vector_accumulated);
 707
 708                         if (dc->hatch_spacing != 0) { // spacing was already set
 709                             double target;
 710                             if (speed > SPEED_NORMAL) {
 711                                 // all ok, strictly obey the spacing
 712                                 target = dc->hatch_spacing;
 713                             } else {
 714                                 // looks like we're starting to lose speed,
 715                                 // so _gradually_ let go attraction to prevent jerks
 716                                 target = (dc->hatch_spacing * speed + hatch_dist * (SPEED_NORMAL - speed))/SPEED_NORMAL;
 717                             }
 718                             if (!IS_NAN(dot) && dot < -0.5) {// flip
 719                                 target = -target;
 720                             }
 721
 722                             // This is the track pointer that we will use instead of the real one
 723                             Geom::Point new_pointer = nearest + target * hatch_unit_vector;
 724
 725                             // some limited feedback: allow persistent pulling to slightly change
 726                             // the spacing
 727                             dc->hatch_spacing += (hatch_dist - dc->hatch_spacing)/3500;
 728
 729                             // return it to the desktop coords
 730                             motion_dt = new_pointer * motion_to_curve.inverse();
 731
 732                             if (speed >= SPEED_NORMAL) {
 733                                 dc->inertia_vectors.push_front(motion_dt);
 734                                 if (dc->inertia_vectors.size() > INERTIA_ELEMENTS)
 735                                     dc->inertia_vectors.pop_back();
 736                             }
 737
 738                         } else {
 739                             // this is the first motion event, set the dist
 740                             dc->hatch_spacing = hatch_dist;
 741                         }
 742
 743                         // remember last points
 744                         dc->hatch_last_pointer = pointer;
 745                         dc->hatch_last_nearest = nearest;
 746
 747                         dc->hatch_vectors.push_front(pointer - nearest);
 748                         if (dc->hatch_vectors.size() > HATCH_VECTOR_ELEMENTS)
 749                             dc->hatch_vectors.pop_back();
 750                     }
 751
 752                     dc->_message_context->set(Inkscape::NORMAL_MESSAGE, dc->hatch_escaped? _("Tracking: <b>connection to guide path lost!</b>") : _("<b>Tracking</b> a guide path"));
 753
 754                 } else {
 755                     dc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("<b>Drawing</b> a calligraphic stroke"));
 756                 }
 757
 758                 if (dc->just_started_drawing) {
 759                     dc->just_started_drawing = false;
 760                     sp_dyna_draw_reset(dc, motion_dt);
 761                 }
 762
 763                 if (!sp_dyna_draw_apply(dc, motion_dt)) {
 764                     ret = TRUE;
 765                     break;
 766                 }
 767
 768                 if ( dc->cur != dc->last ) {
 769                     sp_dyna_draw_brush(dc);
 770                     g_assert( dc->npoints > 0 );
 771                     fit_and_split(dc, FALSE);
 772                 }
 773                 ret = TRUE;
 774             }
 775
 776             // Draw the hatching circle if necessary
 777             if (event->motion.state & GDK_CONTROL_MASK) {
 778                 if (dc->hatch_spacing == 0 && hatch_dist != 0) {
 779                     // Haven't set spacing yet: gray, center free, update radius live
 780                     Geom::Point c = desktop->w2d(motion_w);
 781                     Geom::Matrix const sm (Geom::Scale(hatch_dist, hatch_dist) * Geom::Translate(c));
 782                     sp_canvas_item_affine_absolute(dc->hatch_area, sm);
 783                     sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(dc->hatch_area), 0x7f7f7fff, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 784                     sp_canvas_item_show(dc->hatch_area);
 785                 } else if (dc->dragging && !dc->hatch_escaped) {
 786                     // Tracking: green, center snapped, fixed radius
 787                     Geom::Point c = motion_dt;
 788                     Geom::Matrix const sm (Geom::Scale(dc->hatch_spacing, dc->hatch_spacing) * Geom::Translate(c));
 789                     sp_canvas_item_affine_absolute(dc->hatch_area, sm);
 790                     sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(dc->hatch_area), 0x00FF00ff, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 791                     sp_canvas_item_show(dc->hatch_area);
 792                 } else if (dc->dragging && dc->hatch_escaped) {
 793                     // Tracking escaped: red, center free, fixed radius
 794                     Geom::Point c = motion_dt;
 795                     Geom::Matrix const sm (Geom::Scale(dc->hatch_spacing, dc->hatch_spacing) * Geom::Translate(c));
 796
 797                     sp_canvas_item_affine_absolute(dc->hatch_area, sm);
 798                     sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(dc->hatch_area), 0xFF0000ff, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 799                     sp_canvas_item_show(dc->hatch_area);
 800                 } else {
 801                     // Not drawing but spacing set: gray, center snapped, fixed radius
 802                     Geom::Point c = (nearest + dc->hatch_spacing * hatch_unit_vector) * motion_to_curve.inverse();
 803                     if (!IS_NAN(c[Geom::X]) && !IS_NAN(c[Geom::Y])) {
 804                         Geom::Matrix const sm (Geom::Scale(dc->hatch_spacing, dc->hatch_spacing) * Geom::Translate(c));
 805                         sp_canvas_item_affine_absolute(dc->hatch_area, sm);
 806                         sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(dc->hatch_area), 0x7f7f7fff, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 807                         sp_canvas_item_show(dc->hatch_area);
 808                     }
 809                 }
 810             } else {
 811                 sp_canvas_item_hide(dc->hatch_area);
 812             }
 813         }
 814         break;
 815
 816
 817     case GDK_BUTTON_RELEASE:
 818     {
 819         Geom::Point const motion_w(event->button.x, event->button.y);
 820         Geom::Point const motion_dt(desktop->w2d(motion_w));
 821
 822         sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate), event->button.time);
 823         sp_canvas_end_forced_full_redraws(desktop->canvas);
 824         dc->is_drawing = false;
 825
 826         if (dc->dragging && event->button.button == 1 && !event_context->space_panning) {
 827             dc->dragging = FALSE;
 828
 829             sp_dyna_draw_apply(dc, motion_dt);
 830
 831             /* Remove all temporary line segments */
 832             while (dc->segments) {
 833                 gtk_object_destroy(GTK_OBJECT(dc->segments->data));
 834                 dc->segments = g_slist_remove(dc->segments, dc->segments->data);
 835             }
 836
 837             /* Create object */
 838             fit_and_split(dc, TRUE);
 839             if (accumulate_calligraphic(dc))
 840                 set_to_accumulated(dc, event->button.state & GDK_SHIFT_MASK, event->button.state & GDK_MOD1_MASK); // performs document_done
 841             else
 842                 g_warning ("Failed to create path: invalid data in dc->cal1 or dc->cal2");
 843
 844             /* reset accumulated curve */
 845             dc->accumulated->reset();
 846
 847             clear_current(dc);
 848             if (dc->repr) {
 849                 dc->repr = NULL;
 850             }
 851
 852             if (!dc->hatch_pointer_past.empty()) dc->hatch_pointer_past.clear();
 853             if (!dc->hatch_nearest_past.empty()) dc->hatch_nearest_past.clear();
 854             if (!dc->inertia_vectors.empty()) dc->inertia_vectors.clear();
 855             if (!dc->hatch_vectors.empty()) dc->hatch_vectors.clear();
 856             dc->hatch_last_nearest = Geom::Point(0,0);
 857             dc->hatch_last_pointer = Geom::Point(0,0);
 858             dc->hatch_escaped = false;
 859             dc->hatch_item = NULL;
 860             dc->hatch_livarot_path = NULL;
 861             dc->just_started_drawing = false;
 862
 863             if (dc->hatch_spacing != 0 && !dc->keep_selected) {
 864                 // we do not select the newly drawn path, so increase spacing by step
 865                 if (dc->hatch_spacing_step == 0) {
 866                     dc->hatch_spacing_step = dc->hatch_spacing;
 867                 }
 868                 dc->hatch_spacing += dc->hatch_spacing_step;
 869             }
 870
 871             dc->_message_context->clear();
 872             ret = TRUE;
 873         }
 874         break;
 875     }
 876
 877     case GDK_KEY_PRESS:
 878         switch (get_group0_keyval (&event->key)) {
 879         case GDK_Up:
 880         case GDK_KP_Up:
 881             if (!MOD__CTRL_ONLY) {
 882                 dc->angle += 5.0;
 883                 if (dc->angle > 90.0)
 884                     dc->angle = 90.0;
 885                 sp_ddc_update_toolbox (desktop, "calligraphy-angle", dc->angle);
 886                 ret = TRUE;
 887             }
 888             break;
 889         case GDK_Down:
 890         case GDK_KP_Down:
 891             if (!MOD__CTRL_ONLY) {
 892                 dc->angle -= 5.0;
 893                 if (dc->angle < -90.0)
 894                     dc->angle = -90.0;
 895                 sp_ddc_update_toolbox (desktop, "calligraphy-angle", dc->angle);
 896                 ret = TRUE;
 897             }
 898             break;
 899         case GDK_Right:
 900         case GDK_KP_Right:
 901             if (!MOD__CTRL_ONLY) {
 902                 dc->width += 0.01;
 903                 if (dc->width > 1.0)
 904                     dc->width = 1.0;
 905                 sp_ddc_update_toolbox (desktop, "altx-calligraphy", dc->width * 100); // the same spinbutton is for alt+x
 906                 ret = TRUE;
 907             }
 908             break;
 909         case GDK_Left:
 910         case GDK_KP_Left:
 911             if (!MOD__CTRL_ONLY) {
 912                 dc->width -= 0.01;
 913                 if (dc->width < 0.01)
 914                     dc->width = 0.01;
 915                 sp_ddc_update_toolbox (desktop, "altx-calligraphy", dc->width * 100);
 916                 ret = TRUE;
 917             }
 918             break;
 919         case GDK_Home:
 920         case GDK_KP_Home:
 921             dc->width = 0.01;
 922             sp_ddc_update_toolbox (desktop, "altx-calligraphy", dc->width * 100);
 923             ret = TRUE;
 924             break;
 925         case GDK_End:
 926         case GDK_KP_End:
 927             dc->width = 1.0;
 928             sp_ddc_update_toolbox (desktop, "altx-calligraphy", dc->width * 100);
 929             ret = TRUE;
 930             break;
 931         case GDK_x:
 932         case GDK_X:
 933             if (MOD__ALT_ONLY) {
 934                 desktop->setToolboxFocusTo ("altx-calligraphy");
 935                 ret = TRUE;
 936             }
 937             break;
 938         case GDK_Escape:
 939             if (dc->is_drawing) {
 940                 // if drawing, cancel, otherwise pass it up for deselecting
 941                 calligraphic_cancel (dc);
 942                 ret = TRUE;
 943             }
 944             break;
 945         case GDK_z:
 946         case GDK_Z:
 947             if (MOD__CTRL_ONLY && dc->is_drawing) {
 948                 // if drawing, cancel, otherwise pass it up for undo
 949                 calligraphic_cancel (dc);
 950                 ret = TRUE;
 951             }
 952             break;
 953         default:
 954             break;
 955         }
 956         break;
 957
 958     case GDK_KEY_RELEASE:
 959         switch (get_group0_keyval(&event->key)) {
 960             case GDK_Control_L:
 961             case GDK_Control_R:
 962                 dc->_message_context->clear();
 963                 dc->hatch_spacing = 0;
 964                 dc->hatch_spacing_step = 0;
 965                 break;
 966             default:
 967                 break;
 968         }
 969
 970     default:
 971         break;
 972     }
 973
 974     if (!ret) {
 975         if (((SPEventContextClass *) dd_parent_class)->root_handler) {
 976             ret = ((SPEventContextClass *) dd_parent_class)->root_handler(event_context, event);
 977         }
 978     }
 979
 980     return ret;
 981 }
 982
 983
 984 static void
 985 clear_current(SPDynaDrawContext *dc)
 986 {
 987     /* reset bpath */
 988     sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(dc->currentshape), NULL);
 989     /* reset curve */
 990     dc->currentcurve->reset();
 991     dc->cal1->reset();
 992     dc->cal2->reset();
 993     /* reset points */
 994     dc->npoints = 0;
 995 }
 996
 997 static void
 998 set_to_accumulated(SPDynaDrawContext *dc, bool unionize, bool subtract)
 999 {
1000     SPDesktop *desktop = SP_EVENT_CONTEXT(dc)->desktop;
1001
1002     if (!dc->accumulated->is_empty()) {
1003         if (!dc->repr) {
1004             /* Create object */
1005             Inkscape::XML::Document *xml_doc = sp_document_repr_doc(desktop->doc());
1006             Inkscape::XML::Node *repr = xml_doc->createElement("svg:path");
1007
1008             /* Set style */
1009             sp_desktop_apply_style_tool (desktop, repr, "/tools/calligraphic", false);
1010
1011             dc->repr = repr;
1012
1013             SPItem *item=SP_ITEM(desktop->currentLayer()->appendChildRepr(dc->repr));
1014             Inkscape::GC::release(dc->repr);
1015             item->transform = sp_item_i2doc_affine(SP_ITEM(desktop->currentLayer())).inverse();
1016             item->updateRepr();
1017         }
1018         Geom::PathVector pathv = dc->accumulated->get_pathvector() * desktop->dt2doc();
1019         gchar *str = sp_svg_write_path(pathv);
1020         g_assert( str != NULL );
1021         dc->repr->setAttribute("d", str);
1022         g_free(str);
1023
1024         if (unionize) {
1025             sp_desktop_selection(desktop)->add(dc->repr);
1026             sp_selected_path_union_skip_undo(desktop);
1027         } else if (subtract) {
1028             sp_desktop_selection(desktop)->add(dc->repr);
1029             sp_selected_path_diff_skip_undo(desktop);
1030         } else {
1031             if (dc->keep_selected) {
1032                 sp_desktop_selection(desktop)->set(dc->repr);
1033             }
1034         }
1035
1036     } else {
1037         if (dc->repr) {
1038             sp_repr_unparent(dc->repr);
1039         }
1040         dc->repr = NULL;
1041     }
1042
1043     sp_document_done(sp_desktop_document(desktop), SP_VERB_CONTEXT_CALLIGRAPHIC,
1044                      _("Draw calligraphic stroke"));
1045 }
1046
1047 static void
1048 add_cap(SPCurve *curve,
1049         Geom::Point const &from,
1050         Geom::Point const &to,
1051         double rounding)
1052 {
1053     if (Geom::L2( to - from ) > DYNA_EPSILON) {
1054         Geom::Point vel = rounding * Geom::rot90( to - from ) / sqrt(2.0);
1055         double mag = Geom::L2(vel);
1056
1057         Geom::Point v = mag * Geom::rot90( to - from ) / Geom::L2( to - from );
1058         curve->curveto(from + v, to + v, to);
1059     }
1060 }
1061
1062 static bool
1063 accumulate_calligraphic(SPDynaDrawContext *dc)
1064 {
1065         if (
1066             dc->cal1->is_empty() ||
1067             dc->cal2->is_empty() ||
1068             (dc->cal1->get_segment_count() <= 0) ||
1069             dc->cal1->first_path()->closed()
1070             ) {
1071             dc->cal1->reset();
1072             dc->cal2->reset();
1073             return false; // failure
1074         }
1075
1076         SPCurve *rev_cal2 = dc->cal2->create_reverse();
1077         if (
1078             (rev_cal2->get_segment_count() <= 0) ||
1079             rev_cal2->first_path()->closed()
1080             ) {
1081             rev_cal2->unref();
1082             dc->cal1->reset();
1083             dc->cal2->reset();
1084             return false; // failure
1085         }
1086
1087         Geom::CubicBezier const * dc_cal1_firstseg  = dynamic_cast<Geom::CubicBezier const *>( dc->cal1->first_segment() );
1088         Geom::CubicBezier const * rev_cal2_firstseg = dynamic_cast<Geom::CubicBezier const *>( rev_cal2->first_segment() );
1089         Geom::CubicBezier const * dc_cal1_lastseg   = dynamic_cast<Geom::CubicBezier const *>( dc->cal1->last_segment() );
1090         Geom::CubicBezier const * rev_cal2_lastseg  = dynamic_cast<Geom::CubicBezier const *>( rev_cal2->last_segment() );
1091
1092         if (
1093             !dc_cal1_firstseg ||
1094             !rev_cal2_firstseg ||
1095             !dc_cal1_lastseg ||
1096             !rev_cal2_lastseg
1097             ) {
1098             rev_cal2->unref();
1099             dc->cal1->reset();
1100             dc->cal2->reset();
1101             return false; // failure
1102         }
1103
1104         dc->accumulated->reset(); /*  Is this required ?? */
1105
1106         dc->accumulated->append(dc->cal1, false);
1107
1108         add_cap(dc->accumulated, (*dc_cal1_lastseg)[3], (*rev_cal2_firstseg)[0], dc->cap_rounding);
1109
1110         dc->accumulated->append(rev_cal2, true);
1111
1112         add_cap(dc->accumulated, (*rev_cal2_lastseg)[3], (*dc_cal1_firstseg)[0], dc->cap_rounding);
1113
1114         dc->accumulated->closepath();
1115
1116         rev_cal2->unref();
1117
1118         dc->cal1->reset();
1119         dc->cal2->reset();
1120
1121         return true; // success
1122 }
1123
1124 static double square(double const x)
1125 {
1126     return x * x;
1127 }
1128
1129 static void
1130 fit_and_split(SPDynaDrawContext *dc, gboolean release)
1131 {
1132     SPDesktop *desktop = SP_EVENT_CONTEXT(dc)->desktop;
1133
1134     double const tolerance_sq = square( desktop->w2d().descrim() * TOLERANCE_CALLIGRAPHIC );
1135
1136 #ifdef DYNA_DRAW_VERBOSE
1137     g_print("[F&S:R=%c]", release?'T':'F');
1138 #endif
1139
1140     if (!( dc->npoints > 0 && dc->npoints < SAMPLING_SIZE ))
1141         return; // just clicked
1142
1143     if ( dc->npoints == SAMPLING_SIZE - 1 || release ) {
1144 #define BEZIER_SIZE       4
1145 #define BEZIER_MAX_BEZIERS  8
1146 #define BEZIER_MAX_LENGTH ( BEZIER_SIZE * BEZIER_MAX_BEZIERS )
1147
1148 #ifdef DYNA_DRAW_VERBOSE
1149         g_print("[F&S:#] dc->npoints:%d, release:%s\n",
1150                 dc->npoints, release ? "TRUE" : "FALSE");
1151 #endif
1152
1153         /* Current calligraphic */
1154         if ( dc->cal1->is_empty() || dc->cal2->is_empty() ) {
1155             /* dc->npoints > 0 */
1156             /* g_print("calligraphics(1|2) reset\n"); */
1157             dc->cal1->reset();
1158             dc->cal2->reset();
1159
1160             dc->cal1->moveto(dc->point1[0]);
1161             dc->cal2->moveto(dc->point2[0]);
1162         }
1163
1164         Geom::Point b1[BEZIER_MAX_LENGTH];
1165         gint const nb1 = Geom::bezier_fit_cubic_r(b1, dc->point1, dc->npoints,
1166                                                tolerance_sq, BEZIER_MAX_BEZIERS);
1167         g_assert( nb1 * BEZIER_SIZE <= gint(G_N_ELEMENTS(b1)) );
1168
1169         Geom::Point b2[BEZIER_MAX_LENGTH];
1170         gint const nb2 = Geom::bezier_fit_cubic_r(b2, dc->point2, dc->npoints,
1171                                                tolerance_sq, BEZIER_MAX_BEZIERS);
1172         g_assert( nb2 * BEZIER_SIZE <= gint(G_N_ELEMENTS(b2)) );
1173
1174         if ( nb1 != -1 && nb2 != -1 ) {
1175             /* Fit and draw and reset state */
1176 #ifdef DYNA_DRAW_VERBOSE
1177             g_print("nb1:%d nb2:%d\n", nb1, nb2);
1178 #endif
1179             /* CanvasShape */
1180             if (! release) {
1181                 dc->currentcurve->reset();
1182                 dc->currentcurve->moveto(b1[0]);
1183                 for (Geom::Point *bp1 = b1; bp1 < b1 + BEZIER_SIZE * nb1; bp1 += BEZIER_SIZE) {
1184                     dc->currentcurve->curveto(bp1[1], bp1[2], bp1[3]);
1185                 }
1186                 dc->currentcurve->lineto(b2[BEZIER_SIZE*(nb2-1) + 3]);
1187                 for (Geom::Point *bp2 = b2 + BEZIER_SIZE * ( nb2 - 1 ); bp2 >= b2; bp2 -= BEZIER_SIZE) {
1188                     dc->currentcurve->curveto(bp2[2], bp2[1], bp2[0]);
1189                 }
1190                 // FIXME: dc->segments is always NULL at this point??
1191                 if (!dc->segments) { // first segment
1192                     add_cap(dc->currentcurve, b2[0], b1[0], dc->cap_rounding);
1193                 }
1194                 dc->currentcurve->closepath();
1195                 sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(dc->currentshape), dc->currentcurve);
1196             }
1197
1198             /* Current calligraphic */
1199             for (Geom::Point *bp1 = b1; bp1 < b1 + BEZIER_SIZE * nb1; bp1 += BEZIER_SIZE) {
1200                 dc->cal1->curveto(bp1[1], bp1[2], bp1[3]);
1201             }
1202             for (Geom::Point *bp2 = b2; bp2 < b2 + BEZIER_SIZE * nb2; bp2 += BEZIER_SIZE) {
1203                 dc->cal2->curveto(bp2[1], bp2[2], bp2[3]);
1204             }
1205         } else {
1206             /* fixme: ??? */
1207 #ifdef DYNA_DRAW_VERBOSE
1208             g_print("[fit_and_split] failed to fit-cubic.\n");
1209 #endif
1210             draw_temporary_box(dc);
1211
1212             for (gint i = 1; i < dc->npoints; i++) {
1213                 dc->cal1->lineto(dc->point1[i]);
1214             }
1215             for (gint i = 1; i < dc->npoints; i++) {
1216                 dc->cal2->lineto(dc->point2[i]);
1217             }
1218         }
1219
1220         /* Fit and draw and copy last point */
1221 #ifdef DYNA_DRAW_VERBOSE
1222         g_print("[%d]Yup\n", dc->npoints);
1223 #endif
1224         if (!release) {
1225             g_assert(!dc->currentcurve->is_empty());
1226
1227             SPCanvasItem *cbp = sp_canvas_item_new(sp_desktop_sketch(desktop),
1228                                                    SP_TYPE_CANVAS_BPATH,
1229                                                    NULL);
1230             SPCurve *curve = dc->currentcurve->copy();
1231             sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH (cbp), curve);
1232             curve->unref();
1233
1234             guint32 fillColor = sp_desktop_get_color_tool (desktop, "/tools/calligraphic", true);
1235             //guint32 strokeColor = sp_desktop_get_color_tool (desktop, "/tools/calligraphic", false);
1236             double opacity = sp_desktop_get_master_opacity_tool (desktop, "/tools/calligraphic");
1237             double fillOpacity = sp_desktop_get_opacity_tool (desktop, "/tools/calligraphic", true);
1238             //double strokeOpacity = sp_desktop_get_opacity_tool (desktop, "/tools/calligraphic", false);
1239             sp_canvas_bpath_set_fill(SP_CANVAS_BPATH(cbp), ((fillColor & 0xffffff00) | SP_COLOR_F_TO_U(opacity*fillOpacity)), SP_WIND_RULE_EVENODD);
1240             //on second thougtht don't do stroke yet because we don't have stoke-width yet and because stoke appears between segments while drawing
1241             //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);
1242             sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(cbp), 0x00000000, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
1243             /* fixme: Cannot we cascade it to root more clearly? */
1244             g_signal_connect(G_OBJECT(cbp), "event", G_CALLBACK(sp_desktop_root_handler), desktop);
1245
1246             dc->segments = g_slist_prepend(dc->segments, cbp);
1247         }
1248
1249         dc->point1[0] = dc->point1[dc->npoints - 1];
1250         dc->point2[0] = dc->point2[dc->npoints - 1];
1251         dc->npoints = 1;
1252     } else {
1253         draw_temporary_box(dc);
1254     }
1255 }
1256
1257 static void
1258 draw_temporary_box(SPDynaDrawContext *dc)
1259 {
1260     dc->currentcurve->reset();
1261
1262     dc->currentcurve->moveto(dc->point2[dc->npoints-1]);
1263     for (gint i = dc->npoints-2; i >= 0; i--) {
1264         dc->currentcurve->lineto(dc->point2[i]);
1265     }
1266     for (gint i = 0; i < dc->npoints; i++) {
1267         dc->currentcurve->lineto(dc->point1[i]);
1268     }
1269
1270     if (dc->npoints >= 2) {
1271         add_cap(dc->currentcurve, dc->point1[dc->npoints-1], dc->point2[dc->npoints-1], dc->cap_rounding);
1272     }
1273
1274     dc->currentcurve->closepath();
1275     sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(dc->currentshape), dc->currentcurve);
1276 }
1277
1278 /*
1279   Local Variables:
1280   mode:c++
1281   c-file-style:"stroustrup"
1282   c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
1283   indent-tabs-mode:nil
1284   fill-column:99
1285   End:
1286 */
1287 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :