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-affine.h"
  49 #include "desktop-style.h"
  50 #include "message-context.h"
  51 #include "preferences.h"
  52 #include "pixmaps/cursor-calligraphy.xpm"
  53 #include "xml/repr.h"
  54 #include "context-fns.h"
  55 #include "sp-item.h"
  56 #include "inkscape.h"
  57 #include "color.h"
  58 #include "splivarot.h"
  59 #include "sp-item-group.h"
  60 #include "sp-shape.h"
  61 #include "sp-path.h"
  62 #include "sp-text.h"
  63 #include "display/canvas-bpath.h"
  64 #include "display/canvas-arena.h"
  65 #include "livarot/Shape.h"
  66
  67 #include "dyna-draw-context.h"
  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);
  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 = sp_item_dt2i_affine(selected) * sp_item_i2doc_affine(selected);
 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 36
 629 #define SPEED_ELEMENTS 12
 630 #define SPEED_MIN 0.3
 631 #define SPEED_NORMAL 0.3
 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() + should_have_moved;
 694                             }
 695                         }
 696
 697                     } else {
 698
 699                         // Calculate angle cosine of this vector-to-guide and all past vectors
 700                         // summed, to detect if we accidentally flipped to the other side of the
 701                         // guide
 702                         Geom::Point hatch_vector_accumulated = std::accumulate
 703                             (dc->hatch_vectors.begin(), dc->hatch_vectors.end(), Geom::Point(0,0));
 704                         double dot = Geom::dot (pointer - nearest, hatch_vector_accumulated);
 705                         dot /= Geom::L2(pointer - nearest) * Geom::L2(hatch_vector_accumulated);
 706
 707                         if (dc->hatch_spacing != 0) { // spacing was already set
 708                             double target;
 709                             if (speed > SPEED_NORMAL) {
 710                                 // all ok, strictly obey the spacing
 711                                 target = dc->hatch_spacing;
 712                             } else {
 713                                 // looks like we're starting to lose speed,
 714                                 // so _gradually_ let go attraction to prevent jerks
 715                                 target = (dc->hatch_spacing * speed + hatch_dist * (SPEED_NORMAL - speed))/SPEED_NORMAL;
 716                             }
 717                             if (!IS_NAN(dot) && dot < -0.5) {// flip
 718                                 target = -target;
 719                             }
 720
 721                             // This is the track pointer that we will use instead of the real one
 722                             Geom::Point new_pointer = nearest + target * hatch_unit_vector;
 723
 724                             // some limited feedback: allow persistent pulling to slightly change
 725                             // the spacing
 726                             dc->hatch_spacing += (hatch_dist - dc->hatch_spacing)/3500;
 727
 728                             // return it to the desktop coords
 729                             motion_dt = new_pointer * motion_to_curve.inverse();
 730
 731                             if (speed >= SPEED_NORMAL) {
 732                                 dc->inertia_vectors.push_front(motion_dt);
 733                                 if (dc->inertia_vectors.size() > INERTIA_ELEMENTS)
 734                                     dc->inertia_vectors.pop_back();
 735                             }
 736
 737                         } else {
 738                             // this is the first motion event, set the dist
 739                             dc->hatch_spacing = hatch_dist;
 740                         }
 741
 742                         // remember last points
 743                         dc->hatch_last_pointer = pointer;
 744                         dc->hatch_last_nearest = nearest;
 745
 746                         dc->hatch_vectors.push_front(pointer - nearest);
 747                         if (dc->hatch_vectors.size() > HATCH_VECTOR_ELEMENTS)
 748                             dc->hatch_vectors.pop_back();
 749                     }
 750
 751                     dc->_message_context->set(Inkscape::NORMAL_MESSAGE, dc->hatch_escaped? _("Tracking: <b>connection to guide path lost!</b>") : _("<b>Tracking</b> a guide path"));
 752
 753                 } else {
 754                     dc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("<b>Drawing</b> a calligraphic stroke"));
 755                 }
 756
 757                 if (dc->just_started_drawing) {
 758                     dc->just_started_drawing = false;
 759                     sp_dyna_draw_reset(dc, motion_dt);
 760                 }
 761
 762                 if (!sp_dyna_draw_apply(dc, motion_dt)) {
 763                     ret = TRUE;
 764                     break;
 765                 }
 766
 767                 if ( dc->cur != dc->last ) {
 768                     sp_dyna_draw_brush(dc);
 769                     g_assert( dc->npoints > 0 );
 770                     fit_and_split(dc, FALSE);
 771                 }
 772                 ret = TRUE;
 773             }
 774
 775             // Draw the hatching circle if necessary
 776             if (event->motion.state & GDK_CONTROL_MASK) {
 777                 if (dc->hatch_spacing == 0 && hatch_dist != 0) {
 778                     // Haven't set spacing yet: gray, center free, update radius live
 779                     Geom::Point c = desktop->w2d(motion_w);
 780                     Geom::Matrix const sm (Geom::Scale(hatch_dist, hatch_dist) * Geom::Translate(c));
 781                     sp_canvas_item_affine_absolute(dc->hatch_area, sm);
 782                     sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(dc->hatch_area), 0x7f7f7fff, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 783                     sp_canvas_item_show(dc->hatch_area);
 784                 } else if (dc->dragging && !dc->hatch_escaped) {
 785                     // Tracking: green, center snapped, fixed radius
 786                     Geom::Point c = motion_dt;
 787                     Geom::Matrix const sm (Geom::Scale(dc->hatch_spacing, dc->hatch_spacing) * Geom::Translate(c));
 788                     sp_canvas_item_affine_absolute(dc->hatch_area, sm);
 789                     sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(dc->hatch_area), 0x00FF00ff, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 790                     sp_canvas_item_show(dc->hatch_area);
 791                 } else if (dc->dragging && dc->hatch_escaped) {
 792                     // Tracking escaped: red, center free, fixed radius
 793                     Geom::Point c = motion_dt;
 794                     Geom::Matrix const sm (Geom::Scale(dc->hatch_spacing, dc->hatch_spacing) * Geom::Translate(c));
 795
 796                     sp_canvas_item_affine_absolute(dc->hatch_area, sm);
 797                     sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(dc->hatch_area), 0xFF0000ff, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 798                     sp_canvas_item_show(dc->hatch_area);
 799                 } else {
 800                     // Not drawing but spacing set: gray, center snapped, fixed radius
 801                     Geom::Point c = (nearest + dc->hatch_spacing * hatch_unit_vector) * motion_to_curve.inverse();
 802                     if (!IS_NAN(c[Geom::X]) && !IS_NAN(c[Geom::Y])) {
 803                         Geom::Matrix const sm (Geom::Scale(dc->hatch_spacing, dc->hatch_spacing) * Geom::Translate(c));
 804                         sp_canvas_item_affine_absolute(dc->hatch_area, sm);
 805                         sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(dc->hatch_area), 0x7f7f7fff, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 806                         sp_canvas_item_show(dc->hatch_area);
 807                     }
 808                 }
 809             } else {
 810                 sp_canvas_item_hide(dc->hatch_area);
 811             }
 812         }
 813         break;
 814
 815
 816     case GDK_BUTTON_RELEASE:
 817     {
 818         Geom::Point const motion_w(event->button.x, event->button.y);
 819         Geom::Point const motion_dt(desktop->w2d(motion_w));
 820
 821         sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate), event->button.time);
 822         sp_canvas_end_forced_full_redraws(desktop->canvas);
 823         dc->is_drawing = false;
 824
 825         if (dc->dragging && event->button.button == 1 && !event_context->space_panning) {
 826             dc->dragging = FALSE;
 827
 828             sp_dyna_draw_apply(dc, motion_dt);
 829
 830             /* Remove all temporary line segments */
 831             while (dc->segments) {
 832                 gtk_object_destroy(GTK_OBJECT(dc->segments->data));
 833                 dc->segments = g_slist_remove(dc->segments, dc->segments->data);
 834             }
 835
 836             /* Create object */
 837             fit_and_split(dc, TRUE);
 838             if (accumulate_calligraphic(dc))
 839                 set_to_accumulated(dc, event->button.state & GDK_SHIFT_MASK); // performs document_done
 840             else
 841                 g_warning ("Failed to create path: invalid data in dc->cal1 or dc->cal2");
 842
 843             /* reset accumulated curve */
 844             dc->accumulated->reset();
 845
 846             clear_current(dc);
 847             if (dc->repr) {
 848                 dc->repr = NULL;
 849             }
 850
 851             if (!dc->hatch_pointer_past.empty()) dc->hatch_pointer_past.clear();
 852             if (!dc->hatch_nearest_past.empty()) dc->hatch_nearest_past.clear();
 853             if (!dc->inertia_vectors.empty()) dc->inertia_vectors.clear();
 854             if (!dc->hatch_vectors.empty()) dc->hatch_vectors.clear();
 855             dc->hatch_last_nearest = Geom::Point(0,0);
 856             dc->hatch_last_pointer = Geom::Point(0,0);
 857             dc->hatch_escaped = false;
 858             dc->hatch_item = NULL;
 859             dc->hatch_livarot_path = NULL;
 860             dc->just_started_drawing = false;
 861
 862             if (dc->hatch_spacing != 0 && !dc->keep_selected) {
 863                 // we do not select the newly drawn path, so increase spacing by step
 864                 if (dc->hatch_spacing_step == 0) {
 865                     dc->hatch_spacing_step = dc->hatch_spacing;
 866                 }
 867                 dc->hatch_spacing += dc->hatch_spacing_step;
 868             }
 869
 870             dc->_message_context->clear();
 871             ret = TRUE;
 872         }
 873         break;
 874     }
 875
 876     case GDK_KEY_PRESS:
 877         switch (get_group0_keyval (&event->key)) {
 878         case GDK_Up:
 879         case GDK_KP_Up:
 880             if (!MOD__CTRL_ONLY) {
 881                 dc->angle += 5.0;
 882                 if (dc->angle > 90.0)
 883                     dc->angle = 90.0;
 884                 sp_ddc_update_toolbox (desktop, "calligraphy-angle", dc->angle);
 885                 ret = TRUE;
 886             }
 887             break;
 888         case GDK_Down:
 889         case GDK_KP_Down:
 890             if (!MOD__CTRL_ONLY) {
 891                 dc->angle -= 5.0;
 892                 if (dc->angle < -90.0)
 893                     dc->angle = -90.0;
 894                 sp_ddc_update_toolbox (desktop, "calligraphy-angle", dc->angle);
 895                 ret = TRUE;
 896             }
 897             break;
 898         case GDK_Right:
 899         case GDK_KP_Right:
 900             if (!MOD__CTRL_ONLY) {
 901                 dc->width += 0.01;
 902                 if (dc->width > 1.0)
 903                     dc->width = 1.0;
 904                 sp_ddc_update_toolbox (desktop, "altx-calligraphy", dc->width * 100); // the same spinbutton is for alt+x
 905                 ret = TRUE;
 906             }
 907             break;
 908         case GDK_Left:
 909         case GDK_KP_Left:
 910             if (!MOD__CTRL_ONLY) {
 911                 dc->width -= 0.01;
 912                 if (dc->width < 0.01)
 913                     dc->width = 0.01;
 914                 sp_ddc_update_toolbox (desktop, "altx-calligraphy", dc->width * 100);
 915                 ret = TRUE;
 916             }
 917             break;
 918         case GDK_Home:
 919         case GDK_KP_Home:
 920             dc->width = 0.01;
 921             sp_ddc_update_toolbox (desktop, "altx-calligraphy", dc->width * 100);
 922             ret = TRUE;
 923             break;
 924         case GDK_End:
 925         case GDK_KP_End:
 926             dc->width = 1.0;
 927             sp_ddc_update_toolbox (desktop, "altx-calligraphy", dc->width * 100);
 928             ret = TRUE;
 929             break;
 930         case GDK_x:
 931         case GDK_X:
 932             if (MOD__ALT_ONLY) {
 933                 desktop->setToolboxFocusTo ("altx-calligraphy");
 934                 ret = TRUE;
 935             }
 936             break;
 937         case GDK_Escape:
 938             if (dc->is_drawing) {
 939                 // if drawing, cancel, otherwise pass it up for deselecting
 940                 calligraphic_cancel (dc);
 941                 ret = TRUE;
 942             }
 943             break;
 944         case GDK_z:
 945         case GDK_Z:
 946             if (MOD__CTRL_ONLY && dc->is_drawing) {
 947                 // if drawing, cancel, otherwise pass it up for undo
 948                 calligraphic_cancel (dc);
 949                 ret = TRUE;
 950             }
 951             break;
 952         default:
 953             break;
 954         }
 955         break;
 956
 957     case GDK_KEY_RELEASE:
 958         switch (get_group0_keyval(&event->key)) {
 959             case GDK_Control_L:
 960             case GDK_Control_R:
 961                 dc->_message_context->clear();
 962                 dc->hatch_spacing = 0;
 963                 dc->hatch_spacing_step = 0;
 964                 break;
 965             default:
 966                 break;
 967         }
 968
 969     default:
 970         break;
 971     }
 972
 973     if (!ret) {
 974         if (((SPEventContextClass *) dd_parent_class)->root_handler) {
 975             ret = ((SPEventContextClass *) dd_parent_class)->root_handler(event_context, event);
 976         }
 977     }
 978
 979     return ret;
 980 }
 981
 982
 983 static void
 984 clear_current(SPDynaDrawContext *dc)
 985 {
 986     /* reset bpath */
 987     sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(dc->currentshape), NULL);
 988     /* reset curve */
 989     dc->currentcurve->reset();
 990     dc->cal1->reset();
 991     dc->cal2->reset();
 992     /* reset points */
 993     dc->npoints = 0;
 994 }
 995
 996 static void
 997 set_to_accumulated(SPDynaDrawContext *dc, bool unionize)
 998 {
 999     SPDesktop *desktop = SP_EVENT_CONTEXT(dc)->desktop;
1000
1001     if (!dc->accumulated->is_empty()) {
1002         if (!dc->repr) {
1003             /* Create object */
1004             Inkscape::XML::Document *xml_doc = sp_document_repr_doc(desktop->doc());
1005             Inkscape::XML::Node *repr = xml_doc->createElement("svg:path");
1006
1007             /* Set style */
1008             sp_desktop_apply_style_tool (desktop, repr, "/tools/calligraphic", false);
1009
1010             dc->repr = repr;
1011
1012             SPItem *item=SP_ITEM(desktop->currentLayer()->appendChildRepr(dc->repr));
1013             Inkscape::GC::release(dc->repr);
1014             item->transform = sp_item_i2doc_affine(SP_ITEM(desktop->currentLayer())).inverse();
1015             item->updateRepr();
1016         }
1017         Geom::PathVector pathv = dc->accumulated->get_pathvector() * sp_desktop_dt2doc_affine(desktop);
1018         gchar *str = sp_svg_write_path(pathv);
1019         g_assert( str != NULL );
1020         dc->repr->setAttribute("d", str);
1021         g_free(str);
1022
1023         if (unionize) {
1024             sp_desktop_selection(desktop)->add(dc->repr);
1025             sp_selected_path_union_skip_undo(desktop);
1026         } else {
1027             if (dc->keep_selected) {
1028                 sp_desktop_selection(desktop)->set(dc->repr);
1029             }
1030         }
1031
1032     } else {
1033         if (dc->repr) {
1034             sp_repr_unparent(dc->repr);
1035         }
1036         dc->repr = NULL;
1037     }
1038
1039     sp_document_done(sp_desktop_document(desktop), SP_VERB_CONTEXT_CALLIGRAPHIC,
1040                      _("Draw calligraphic stroke"));
1041 }
1042
1043 static void
1044 add_cap(SPCurve *curve,
1045         Geom::Point const &from,
1046         Geom::Point const &to,
1047         double rounding)
1048 {
1049     if (Geom::L2( to - from ) > DYNA_EPSILON) {
1050         Geom::Point vel = rounding * Geom::rot90( to - from ) / sqrt(2.0);
1051         double mag = Geom::L2(vel);
1052
1053         Geom::Point v = mag * Geom::rot90( to - from ) / Geom::L2( to - from );
1054         curve->curveto(from + v, to + v, to);
1055     }
1056 }
1057
1058 static bool
1059 accumulate_calligraphic(SPDynaDrawContext *dc)
1060 {
1061         if (
1062             dc->cal1->is_empty() ||
1063             dc->cal2->is_empty() ||
1064             (dc->cal1->get_segment_count() <= 0) ||
1065             dc->cal1->first_path()->closed()
1066             ) {
1067             dc->cal1->reset();
1068             dc->cal2->reset();
1069             return false; // failure
1070         }
1071
1072         SPCurve *rev_cal2 = dc->cal2->create_reverse();
1073         if (
1074             (rev_cal2->get_segment_count() <= 0) ||
1075             rev_cal2->first_path()->closed()
1076             ) {
1077             rev_cal2->unref();
1078             dc->cal1->reset();
1079             dc->cal2->reset();
1080             return false; // failure
1081         }
1082
1083         Geom::CubicBezier const * dc_cal1_firstseg  = dynamic_cast<Geom::CubicBezier const *>( dc->cal1->first_segment() );
1084         Geom::CubicBezier const * rev_cal2_firstseg = dynamic_cast<Geom::CubicBezier const *>( rev_cal2->first_segment() );
1085         Geom::CubicBezier const * dc_cal1_lastseg   = dynamic_cast<Geom::CubicBezier const *>( dc->cal1->last_segment() );
1086         Geom::CubicBezier const * rev_cal2_lastseg  = dynamic_cast<Geom::CubicBezier const *>( rev_cal2->last_segment() );
1087
1088         if (
1089             !dc_cal1_firstseg ||
1090             !rev_cal2_firstseg ||
1091             !dc_cal1_lastseg ||
1092             !rev_cal2_lastseg
1093             ) {
1094             rev_cal2->unref();
1095             dc->cal1->reset();
1096             dc->cal2->reset();
1097             return false; // failure
1098         }
1099
1100         dc->accumulated->reset(); /*  Is this required ?? */
1101
1102         dc->accumulated->append(dc->cal1, false);
1103
1104         add_cap(dc->accumulated, (*dc_cal1_lastseg)[3], (*rev_cal2_firstseg)[0], dc->cap_rounding);
1105
1106         dc->accumulated->append(rev_cal2, true);
1107
1108         add_cap(dc->accumulated, (*rev_cal2_lastseg)[3], (*dc_cal1_firstseg)[0], dc->cap_rounding);
1109
1110         dc->accumulated->closepath();
1111
1112         rev_cal2->unref();
1113
1114         dc->cal1->reset();
1115         dc->cal2->reset();
1116
1117         return true; // success
1118 }
1119
1120 static double square(double const x)
1121 {
1122     return x * x;
1123 }
1124
1125 static void
1126 fit_and_split(SPDynaDrawContext *dc, gboolean release)
1127 {
1128     SPDesktop *desktop = SP_EVENT_CONTEXT(dc)->desktop;
1129
1130     double const tolerance_sq = square( desktop->w2d().descrim() * TOLERANCE_CALLIGRAPHIC );
1131
1132 #ifdef DYNA_DRAW_VERBOSE
1133     g_print("[F&S:R=%c]", release?'T':'F');
1134 #endif
1135
1136     if (!( dc->npoints > 0 && dc->npoints < SAMPLING_SIZE ))
1137         return; // just clicked
1138
1139     if ( dc->npoints == SAMPLING_SIZE - 1 || release ) {
1140 #define BEZIER_SIZE       4
1141 #define BEZIER_MAX_BEZIERS  8
1142 #define BEZIER_MAX_LENGTH ( BEZIER_SIZE * BEZIER_MAX_BEZIERS )
1143
1144 #ifdef DYNA_DRAW_VERBOSE
1145         g_print("[F&S:#] dc->npoints:%d, release:%s\n",
1146                 dc->npoints, release ? "TRUE" : "FALSE");
1147 #endif
1148
1149         /* Current calligraphic */
1150         if ( dc->cal1->is_empty() || dc->cal2->is_empty() ) {
1151             /* dc->npoints > 0 */
1152             /* g_print("calligraphics(1|2) reset\n"); */
1153             dc->cal1->reset();
1154             dc->cal2->reset();
1155
1156             dc->cal1->moveto(dc->point1[0]);
1157             dc->cal2->moveto(dc->point2[0]);
1158         }
1159
1160         Geom::Point b1[BEZIER_MAX_LENGTH];
1161         gint const nb1 = Geom::bezier_fit_cubic_r(b1, dc->point1, dc->npoints,
1162                                                tolerance_sq, BEZIER_MAX_BEZIERS);
1163         g_assert( nb1 * BEZIER_SIZE <= gint(G_N_ELEMENTS(b1)) );
1164
1165         Geom::Point b2[BEZIER_MAX_LENGTH];
1166         gint const nb2 = Geom::bezier_fit_cubic_r(b2, dc->point2, dc->npoints,
1167                                                tolerance_sq, BEZIER_MAX_BEZIERS);
1168         g_assert( nb2 * BEZIER_SIZE <= gint(G_N_ELEMENTS(b2)) );
1169
1170         if ( nb1 != -1 && nb2 != -1 ) {
1171             /* Fit and draw and reset state */
1172 #ifdef DYNA_DRAW_VERBOSE
1173             g_print("nb1:%d nb2:%d\n", nb1, nb2);
1174 #endif
1175             /* CanvasShape */
1176             if (! release) {
1177                 dc->currentcurve->reset();
1178                 dc->currentcurve->moveto(b1[0]);
1179                 for (Geom::Point *bp1 = b1; bp1 < b1 + BEZIER_SIZE * nb1; bp1 += BEZIER_SIZE) {
1180                     dc->currentcurve->curveto(bp1[1], bp1[2], bp1[3]);
1181                 }
1182                 dc->currentcurve->lineto(b2[BEZIER_SIZE*(nb2-1) + 3]);
1183                 for (Geom::Point *bp2 = b2 + BEZIER_SIZE * ( nb2 - 1 ); bp2 >= b2; bp2 -= BEZIER_SIZE) {
1184                     dc->currentcurve->curveto(bp2[2], bp2[1], bp2[0]);
1185                 }
1186                 // FIXME: dc->segments is always NULL at this point??
1187                 if (!dc->segments) { // first segment
1188                     add_cap(dc->currentcurve, b2[0], b1[0], dc->cap_rounding);
1189                 }
1190                 dc->currentcurve->closepath();
1191                 sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(dc->currentshape), dc->currentcurve);
1192             }
1193
1194             /* Current calligraphic */
1195             for (Geom::Point *bp1 = b1; bp1 < b1 + BEZIER_SIZE * nb1; bp1 += BEZIER_SIZE) {
1196                 dc->cal1->curveto(bp1[1], bp1[2], bp1[3]);
1197             }
1198             for (Geom::Point *bp2 = b2; bp2 < b2 + BEZIER_SIZE * nb2; bp2 += BEZIER_SIZE) {
1199                 dc->cal2->curveto(bp2[1], bp2[2], bp2[3]);
1200             }
1201         } else {
1202             /* fixme: ??? */
1203 #ifdef DYNA_DRAW_VERBOSE
1204             g_print("[fit_and_split] failed to fit-cubic.\n");
1205 #endif
1206             draw_temporary_box(dc);
1207
1208             for (gint i = 1; i < dc->npoints; i++) {
1209                 dc->cal1->lineto(dc->point1[i]);
1210             }
1211             for (gint i = 1; i < dc->npoints; i++) {
1212                 dc->cal2->lineto(dc->point2[i]);
1213             }
1214         }
1215
1216         /* Fit and draw and copy last point */
1217 #ifdef DYNA_DRAW_VERBOSE
1218         g_print("[%d]Yup\n", dc->npoints);
1219 #endif
1220         if (!release) {
1221             g_assert(!dc->currentcurve->is_empty());
1222
1223             SPCanvasItem *cbp = sp_canvas_item_new(sp_desktop_sketch(desktop),
1224                                                    SP_TYPE_CANVAS_BPATH,
1225                                                    NULL);
1226             SPCurve *curve = dc->currentcurve->copy();
1227             sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH (cbp), curve);
1228             curve->unref();
1229
1230             guint32 fillColor = sp_desktop_get_color_tool (desktop, "/tools/calligraphic", true);
1231             //guint32 strokeColor = sp_desktop_get_color_tool (desktop, "/tools/calligraphic", false);
1232             double opacity = sp_desktop_get_master_opacity_tool (desktop, "/tools/calligraphic");
1233             double fillOpacity = sp_desktop_get_opacity_tool (desktop, "/tools/calligraphic", true);
1234             //double strokeOpacity = sp_desktop_get_opacity_tool (desktop, "/tools/calligraphic", false);
1235             sp_canvas_bpath_set_fill(SP_CANVAS_BPATH(cbp), ((fillColor & 0xffffff00) | SP_COLOR_F_TO_U(opacity*fillOpacity)), SP_WIND_RULE_EVENODD);
1236             //on second thougtht don't do stroke yet because we don't have stoke-width yet and because stoke appears between segments while drawing
1237             //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);
1238             sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(cbp), 0x00000000, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
1239             /* fixme: Cannot we cascade it to root more clearly? */
1240             g_signal_connect(G_OBJECT(cbp), "event", G_CALLBACK(sp_desktop_root_handler), desktop);
1241
1242             dc->segments = g_slist_prepend(dc->segments, cbp);
1243         }
1244
1245         dc->point1[0] = dc->point1[dc->npoints - 1];
1246         dc->point2[0] = dc->point2[dc->npoints - 1];
1247         dc->npoints = 1;
1248     } else {
1249         draw_temporary_box(dc);
1250     }
1251 }
1252
1253 static void
1254 draw_temporary_box(SPDynaDrawContext *dc)
1255 {
1256     dc->currentcurve->reset();
1257
1258     dc->currentcurve->moveto(dc->point2[dc->npoints-1]);
1259     for (gint i = dc->npoints-2; i >= 0; i--) {
1260         dc->currentcurve->lineto(dc->point2[i]);
1261     }
1262     for (gint i = 0; i < dc->npoints; i++) {
1263         dc->currentcurve->lineto(dc->point1[i]);
1264     }
1265
1266     if (dc->npoints >= 2) {
1267         add_cap(dc->currentcurve, dc->point1[dc->npoints-1], dc->point2[dc->npoints-1], dc->cap_rounding);
1268     }
1269
1270     dc->currentcurve->closepath();
1271     sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(dc->currentshape), dc->currentcurve);
1272 }
1273
1274 /*
1275   Local Variables:
1276   mode:c++
1277   c-file-style:"stroustrup"
1278   c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
1279   indent-tabs-mode:nil
1280   fill-column:99
1281   End:
1282 */
1283 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :