src/dyna-draw-context.cpp

   1 /*
   2  * Handwriting-like drawing mode
   3  *
   4  * Authors:
   5  *   Mitsuru Oka <oka326@parkcity.ne.jp>
   6  *   Lauris Kaplinski <lauris@kaplinski.com>
   7  *   bulia byak <buliabyak@users.sf.net>
   8  *   MenTaLguY <mental@rydia.net>
   9  *   Abhishek Sharma
  10  *
  11  * The original dynadraw code:
  12  *   Paul Haeberli <paul@sgi.com>
  13  *
  14  * Copyright (C) 1998 The Free Software Foundation
  15  * Copyright (C) 1999-2005 authors
  16  * Copyright (C) 2001-2002 Ximian, Inc.
  17  * Copyright (C) 2005-2007 bulia byak
  18  * Copyright (C) 2006 MenTaLguY
  19  *
  20  * Released under GNU GPL, read the file 'COPYING' for more information
  21  */
  22
  23 #define noDYNA_DRAW_VERBOSE
  24
  25 #include "config.h"
  26
  27 #include <gtk/gtk.h>
  28 #include <gdk/gdkkeysyms.h>
  29 #include <glibmm/i18n.h>
  30 #include <string>
  31 #include <cstring>
  32 #include <numeric>
  33
  34 #include "svg/svg.h"
  35 #include "display/canvas-bpath.h"
  36 #include <2geom/isnan.h>
  37 #include <2geom/pathvector.h>
  38 #include <2geom/bezier-utils.h>
  39 #include "display/curve.h"
  40 #include <glib/gmem.h>
  41 #include "macros.h"
  42 #include "document.h"
  43 #include "selection.h"
  44 #include "desktop.h"
  45 #include "desktop-events.h"
  46 #include "desktop-handles.h"
  47 #include "desktop-style.h"
  48 #include "message-context.h"
  49 #include "preferences.h"
  50 #include "pixmaps/cursor-calligraphy.xpm"
  51 #include "xml/repr.h"
  52 #include "context-fns.h"
  53 #include "sp-item.h"
  54 #include "inkscape.h"
  55 #include "color.h"
  56 #include "splivarot.h"
  57 #include "sp-item-group.h"
  58 #include "sp-shape.h"
  59 #include "sp-path.h"
  60 #include "sp-text.h"
  61 #include "display/sp-canvas.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 using Inkscape::DocumentUndo;
  69
  70 #define DDC_RED_RGBA 0xff0000ff
  71
  72 #define TOLERANCE_CALLIGRAPHIC 0.1
  73
  74 #define DYNA_EPSILON 0.5e-6
  75 #define DYNA_EPSILON_START 0.5e-2
  76 #define DYNA_VEL_START 1e-5
  77
  78 #define DYNA_MIN_WIDTH 1.0e-6
  79
  80 static void sp_dyna_draw_context_class_init(SPDynaDrawContextClass *klass);
  81 static void sp_dyna_draw_context_init(SPDynaDrawContext *ddc);
  82 static void sp_dyna_draw_context_dispose(GObject *object);
  83
  84 static void sp_dyna_draw_context_setup(SPEventContext *ec);
  85 static void sp_dyna_draw_context_set(SPEventContext *ec, Inkscape::Preferences::Entry *value);
  86 static gint sp_dyna_draw_context_root_handler(SPEventContext *ec, GdkEvent *event);
  87
  88 static void clear_current(SPDynaDrawContext *dc);
  89 static void set_to_accumulated(SPDynaDrawContext *dc, bool unionize, bool subtract);
  90 static void add_cap(SPCurve *curve, Geom::Point const &from, Geom::Point const &to, double rounding);
  91 static bool accumulate_calligraphic(SPDynaDrawContext *dc);
  92
  93 static void fit_and_split(SPDynaDrawContext *ddc, gboolean release);
  94
  95 static void sp_dyna_draw_reset(SPDynaDrawContext *ddc, Geom::Point p);
  96 static Geom::Point sp_dyna_draw_get_npoint(SPDynaDrawContext const *ddc, Geom::Point v);
  97 static Geom::Point sp_dyna_draw_get_vpoint(SPDynaDrawContext const *ddc, Geom::Point n);
  98 static void draw_temporary_box(SPDynaDrawContext *dc);
  99
 100
 101 static SPEventContextClass *dd_parent_class = 0;
 102
 103 GType sp_dyna_draw_context_get_type(void)
 104 {
 105     static GType type = 0;
 106     if (!type) {
 107         GTypeInfo info = {
 108             sizeof(SPDynaDrawContextClass),
 109             0, // base_init
 110             0, // base_finalize
 111             (GClassInitFunc)sp_dyna_draw_context_class_init,
 112             0, // class_finalize
 113             0, // class_data
 114             sizeof(SPDynaDrawContext),
 115             0, // n_preallocs
 116             (GInstanceInitFunc)sp_dyna_draw_context_init,
 117             0 // value_table
 118         };
 119         type = g_type_register_static(SP_TYPE_COMMON_CONTEXT, "SPDynaDrawContext", &info, static_cast<GTypeFlags>(0));
 120     }
 121     return type;
 122 }
 123
 124 static void
 125 sp_dyna_draw_context_class_init(SPDynaDrawContextClass *klass)
 126 {
 127     GObjectClass *object_class = (GObjectClass *) klass;
 128     SPEventContextClass *event_context_class = (SPEventContextClass *) klass;
 129
 130     dd_parent_class = (SPEventContextClass*)g_type_class_peek_parent(klass);
 131
 132     object_class->dispose = sp_dyna_draw_context_dispose;
 133
 134     event_context_class->setup = sp_dyna_draw_context_setup;
 135     event_context_class->set = sp_dyna_draw_context_set;
 136     event_context_class->root_handler = sp_dyna_draw_context_root_handler;
 137 }
 138
 139 static void
 140 sp_dyna_draw_context_init(SPDynaDrawContext *ddc)
 141 {
 142     ddc->cursor_shape = cursor_calligraphy_xpm;
 143     ddc->hot_x = 4;
 144     ddc->hot_y = 4;
 145
 146     ddc->vel_thin = 0.1;
 147     ddc->flatness = 0.9;
 148     ddc->cap_rounding = 0.0;
 149
 150     ddc->abs_width = false;
 151     ddc->keep_selected = true;
 152
 153     ddc->hatch_spacing = 0;
 154     ddc->hatch_spacing_step = 0;
 155     new (&ddc->hatch_pointer_past) std::list<double>();
 156     new (&ddc->hatch_nearest_past) std::list<double>();
 157     new (&ddc->inertia_vectors) std::list<Geom::Point>();
 158     new (&ddc->hatch_vectors) std::list<Geom::Point>();
 159     ddc->hatch_last_nearest = Geom::Point(0,0);
 160     ddc->hatch_last_pointer = Geom::Point(0,0);
 161     ddc->hatch_escaped = false;
 162     ddc->hatch_area = NULL;
 163     ddc->hatch_item = NULL;
 164     ddc->hatch_livarot_path = NULL;
 165
 166     ddc->trace_bg = false;
 167     ddc->just_started_drawing = false;
 168 }
 169
 170 static void
 171 sp_dyna_draw_context_dispose(GObject *object)
 172 {
 173     SPDynaDrawContext *ddc = SP_DYNA_DRAW_CONTEXT(object);
 174
 175     if (ddc->hatch_area) {
 176         gtk_object_destroy(GTK_OBJECT(ddc->hatch_area));
 177         ddc->hatch_area = NULL;
 178     }
 179
 180
 181     G_OBJECT_CLASS(dd_parent_class)->dispose(object);
 182
 183     ddc->hatch_pointer_past.~list();
 184     ddc->hatch_nearest_past.~list();
 185     ddc->inertia_vectors.~list();
 186     ddc->hatch_vectors.~list();
 187 }
 188
 189 static void
 190 sp_dyna_draw_context_setup(SPEventContext *ec)
 191 {
 192     SPDynaDrawContext *ddc = SP_DYNA_DRAW_CONTEXT(ec);
 193
 194     if (((SPEventContextClass *) dd_parent_class)->setup)
 195         ((SPEventContextClass *) dd_parent_class)->setup(ec);
 196
 197     ddc->accumulated = new SPCurve();
 198     ddc->currentcurve = new SPCurve();
 199
 200     ddc->cal1 = new SPCurve();
 201     ddc->cal2 = new SPCurve();
 202
 203     ddc->currentshape = sp_canvas_item_new(sp_desktop_sketch(ec->desktop), SP_TYPE_CANVAS_BPATH, NULL);
 204     sp_canvas_bpath_set_fill(SP_CANVAS_BPATH(ddc->currentshape), DDC_RED_RGBA, SP_WIND_RULE_EVENODD);
 205     sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(ddc->currentshape), 0x00000000, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 206     /* fixme: Cannot we cascade it to root more clearly? */
 207     g_signal_connect(G_OBJECT(ddc->currentshape), "event", G_CALLBACK(sp_desktop_root_handler), ec->desktop);
 208
 209     {
 210         /* 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) */
 211         SPCurve *c = new SPCurve();
 212         const double C1 = 0.552;
 213         c->moveto(-1,0);
 214         c->curveto(-1, C1, -C1, 1, 0, 1 );
 215         c->curveto(C1, 1, 1, C1, 1, 0 );
 216         c->curveto(1, -C1, C1, -1, 0, -1 );
 217         c->curveto(-C1, -1, -1, -C1, -1, 0 );
 218         c->closepath();
 219         ddc->hatch_area = sp_canvas_bpath_new(sp_desktop_controls(ec->desktop), c);
 220         c->unref();
 221         sp_canvas_bpath_set_fill(SP_CANVAS_BPATH(ddc->hatch_area), 0x00000000,(SPWindRule)0);
 222         sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(ddc->hatch_area), 0x0000007f, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 223         sp_canvas_item_hide(ddc->hatch_area);
 224     }
 225
 226     sp_event_context_read(ec, "mass");
 227     sp_event_context_read(ec, "wiggle");
 228     sp_event_context_read(ec, "angle");
 229     sp_event_context_read(ec, "width");
 230     sp_event_context_read(ec, "thinning");
 231     sp_event_context_read(ec, "tremor");
 232     sp_event_context_read(ec, "flatness");
 233     sp_event_context_read(ec, "tracebackground");
 234     sp_event_context_read(ec, "usepressure");
 235     sp_event_context_read(ec, "usetilt");
 236     sp_event_context_read(ec, "abs_width");
 237     sp_event_context_read(ec, "keep_selected");
 238     sp_event_context_read(ec, "cap_rounding");
 239
 240     ddc->is_drawing = false;
 241     ddc->_message_context = new Inkscape::MessageContext((ec->desktop)->messageStack());
 242
 243     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 244     if (prefs->getBool("/tools/calligraphic/selcue")) {
 245         ec->enableSelectionCue();
 246     }
 247 }
 248
 249 static void
 250 sp_dyna_draw_context_set(SPEventContext *ec, Inkscape::Preferences::Entry *val)
 251 {
 252     SPDynaDrawContext *ddc = SP_DYNA_DRAW_CONTEXT(ec);
 253     Glib::ustring path = val->getEntryName();
 254
 255     if (path == "tracebackground") {
 256         ddc->trace_bg = val->getBool();
 257     } else if (path == "keep_selected") {
 258         ddc->keep_selected = val->getBool();
 259     } else {
 260         //pass on up to parent class to handle common attributes.
 261         if ( dd_parent_class->set ) {
 262             dd_parent_class->set(ec, val);
 263         }
 264     }
 265
 266     //g_print("DDC: %g %g %g %g\n", ddc->mass, ddc->drag, ddc->angle, ddc->width);
 267 }
 268
 269 static double
 270 flerp(double f0, double f1, double p)
 271 {
 272     return f0 + ( f1 - f0 ) * p;
 273 }
 274
 275 /* Get normalized point */
 276 static Geom::Point
 277 sp_dyna_draw_get_npoint(SPDynaDrawContext const *dc, Geom::Point v)
 278 {
 279     Geom::Rect drect = SP_EVENT_CONTEXT(dc)->desktop->get_display_area();
 280     double const max = MAX ( drect.dimensions()[Geom::X], drect.dimensions()[Geom::Y] );
 281     return Geom::Point(( v[Geom::X] - drect.min()[Geom::X] ) / max,  ( v[Geom::Y] - drect.min()[Geom::Y] ) / max);
 282 }
 283
 284 /* Get view point */
 285 static Geom::Point
 286 sp_dyna_draw_get_vpoint(SPDynaDrawContext const *dc, Geom::Point n)
 287 {
 288     Geom::Rect drect = SP_EVENT_CONTEXT(dc)->desktop->get_display_area();
 289     double const max = MAX ( drect.dimensions()[Geom::X], drect.dimensions()[Geom::Y] );
 290     return Geom::Point(n[Geom::X] * max + drect.min()[Geom::X], n[Geom::Y] * max + drect.min()[Geom::Y]);
 291 }
 292
 293 static void
 294 sp_dyna_draw_reset(SPDynaDrawContext *dc, Geom::Point p)
 295 {
 296     dc->last = dc->cur = sp_dyna_draw_get_npoint(dc, p);
 297     dc->vel = Geom::Point(0,0);
 298     dc->vel_max = 0;
 299     dc->acc = Geom::Point(0,0);
 300     dc->ang = Geom::Point(0,0);
 301     dc->del = Geom::Point(0,0);
 302 }
 303
 304 static void
 305 sp_dyna_draw_extinput(SPDynaDrawContext *dc, GdkEvent *event)
 306 {
 307     if (gdk_event_get_axis (event, GDK_AXIS_PRESSURE, &dc->pressure))
 308         dc->pressure = CLAMP (dc->pressure, DDC_MIN_PRESSURE, DDC_MAX_PRESSURE);
 309     else
 310         dc->pressure = DDC_DEFAULT_PRESSURE;
 311
 312     if (gdk_event_get_axis (event, GDK_AXIS_XTILT, &dc->xtilt))
 313         dc->xtilt = CLAMP (dc->xtilt, DDC_MIN_TILT, DDC_MAX_TILT);
 314     else
 315         dc->xtilt = DDC_DEFAULT_TILT;
 316
 317     if (gdk_event_get_axis (event, GDK_AXIS_YTILT, &dc->ytilt))
 318         dc->ytilt = CLAMP (dc->ytilt, DDC_MIN_TILT, DDC_MAX_TILT);
 319     else
 320         dc->ytilt = DDC_DEFAULT_TILT;
 321 }
 322
 323
 324 static gboolean
 325 sp_dyna_draw_apply(SPDynaDrawContext *dc, Geom::Point p)
 326 {
 327     Geom::Point n = sp_dyna_draw_get_npoint(dc, p);
 328
 329     /* Calculate mass and drag */
 330     double const mass = flerp(1.0, 160.0, dc->mass);
 331     double const drag = flerp(0.0, 0.5, dc->drag * dc->drag);
 332
 333     /* Calculate force and acceleration */
 334     Geom::Point force = n - dc->cur;
 335
 336     // If force is below the absolute threshold DYNA_EPSILON,
 337     // or we haven't yet reached DYNA_VEL_START (i.e. at the beginning of stroke)
 338     // _and_ the force is below the (higher) DYNA_EPSILON_START threshold,
 339     // discard this move.
 340     // This prevents flips, blobs, and jerks caused by microscopic tremor of the tablet pen,
 341     // especially bothersome at the start of the stroke where we don't yet have the inertia to
 342     // smooth them out.
 343     if ( Geom::L2(force) < DYNA_EPSILON || (dc->vel_max < DYNA_VEL_START && Geom::L2(force) < DYNA_EPSILON_START)) {
 344         return FALSE;
 345     }
 346
 347     dc->acc = force / mass;
 348
 349     /* Calculate new velocity */
 350     dc->vel += dc->acc;
 351
 352     if (Geom::L2(dc->vel) > dc->vel_max)
 353         dc->vel_max = Geom::L2(dc->vel);
 354
 355     /* Calculate angle of drawing tool */
 356
 357     double a1;
 358     if (dc->usetilt) {
 359         // 1a. calculate nib angle from input device tilt:
 360         gdouble length = std::sqrt(dc->xtilt*dc->xtilt + dc->ytilt*dc->ytilt);;
 361
 362         if (length > 0) {
 363             Geom::Point ang1 = Geom::Point(dc->ytilt/length, dc->xtilt/length);
 364             a1 = atan2(ang1);
 365         }
 366         else
 367             a1 = 0.0;
 368     }
 369     else {
 370         // 1b. fixed dc->angle (absolutely flat nib):
 371         double const radians = ( (dc->angle - 90) / 180.0 ) * M_PI;
 372         Geom::Point ang1 = Geom::Point(-sin(radians),  cos(radians));
 373         a1 = atan2(ang1);
 374     }
 375
 376     // 2. perpendicular to dc->vel (absolutely non-flat nib):
 377     gdouble const mag_vel = Geom::L2(dc->vel);
 378     if ( mag_vel < DYNA_EPSILON ) {
 379         return FALSE;
 380     }
 381     Geom::Point ang2 = Geom::rot90(dc->vel) / mag_vel;
 382
 383     // 3. Average them using flatness parameter:
 384     // calculate angles
 385     double a2 = atan2(ang2);
 386     // flip a2 to force it to be in the same half-circle as a1
 387     bool flipped = false;
 388     if (fabs (a2-a1) > 0.5*M_PI) {
 389         a2 += M_PI;
 390         flipped = true;
 391     }
 392     // normalize a2
 393     if (a2 > M_PI)
 394         a2 -= 2*M_PI;
 395     if (a2 < -M_PI)
 396         a2 += 2*M_PI;
 397     // find the flatness-weighted bisector angle, unflip if a2 was flipped
 398     // FIXME: when dc->vel is oscillating around the fixed angle, the new_ang flips back and forth. How to avoid this?
 399     double new_ang = a1 + (1 - dc->flatness) * (a2 - a1) - (flipped? M_PI : 0);
 400
 401     // Try to detect a sudden flip when the new angle differs too much from the previous for the
 402     // current velocity; in that case discard this move
 403     double angle_delta = Geom::L2(Geom::Point (cos (new_ang), sin (new_ang)) - dc->ang);
 404     if ( angle_delta / Geom::L2(dc->vel) > 4000 ) {
 405         return FALSE;
 406     }
 407
 408     // convert to point
 409     dc->ang = Geom::Point (cos (new_ang), sin (new_ang));
 410
 411 //    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);
 412
 413     /* Apply drag */
 414     dc->vel *= 1.0 - drag;
 415
 416     /* Update position */
 417     dc->last = dc->cur;
 418     dc->cur += dc->vel;
 419
 420     return TRUE;
 421 }
 422
 423 static void
 424 sp_dyna_draw_brush(SPDynaDrawContext *dc)
 425 {
 426     g_assert( dc->npoints >= 0 && dc->npoints < SAMPLING_SIZE );
 427
 428     // How much velocity thins strokestyle
 429     double vel_thin = flerp (0, 160, dc->vel_thin);
 430
 431     // Influence of pressure on thickness
 432     double pressure_thick = (dc->usepressure ? dc->pressure : 1.0);
 433
 434     // get the real brush point, not the same as pointer (affected by hatch tracking and/or mass
 435     // drag)
 436     Geom::Point brush = sp_dyna_draw_get_vpoint(dc, dc->cur);
 437     Geom::Point brush_w = SP_EVENT_CONTEXT(dc)->desktop->d2w(brush);
 438
 439     double trace_thick = 1;
 440     if (dc->trace_bg) {
 441         // pick single pixel
 442         NRPixBlock pb;
 443         int x = (int) floor(brush_w[Geom::X]);
 444         int y = (int) floor(brush_w[Geom::Y]);
 445         nr_pixblock_setup_fast(&pb, NR_PIXBLOCK_MODE_R8G8B8A8P, x, y, x+1, y+1, TRUE);
 446         sp_canvas_arena_render_pixblock(SP_CANVAS_ARENA(sp_desktop_drawing(SP_EVENT_CONTEXT(dc)->desktop)), &pb);
 447         const unsigned char *s = NR_PIXBLOCK_PX(&pb);
 448         double R = s[0] / 255.0;
 449         double G = s[1] / 255.0;
 450         double B = s[2] / 255.0;
 451         double A = s[3] / 255.0;
 452         double max = MAX (MAX (R, G), B);
 453         double min = MIN (MIN (R, G), B);
 454         double L = A * (max + min)/2 + (1 - A); // blend with white bg
 455         trace_thick = 1 - L;
 456         //g_print ("L %g thick %g\n", L, trace_thick);
 457     }
 458
 459     double width = (pressure_thick * trace_thick - vel_thin * Geom::L2(dc->vel)) * dc->width;
 460
 461     double tremble_left = 0, tremble_right = 0;
 462     if (dc->tremor > 0) {
 463         // obtain two normally distributed random variables, using polar Box-Muller transform
 464         double x1, x2, w, y1, y2;
 465         do {
 466             x1 = 2.0 * g_random_double_range(0,1) - 1.0;
 467             x2 = 2.0 * g_random_double_range(0,1) - 1.0;
 468             w = x1 * x1 + x2 * x2;
 469         } while ( w >= 1.0 );
 470         w = sqrt( (-2.0 * log( w ) ) / w );
 471         y1 = x1 * w;
 472         y2 = x2 * w;
 473
 474         // deflect both left and right edges randomly and independently, so that:
 475         // (1) dc->tremor=1 corresponds to sigma=1, decreasing dc->tremor narrows the bell curve;
 476         // (2) deflection depends on width, but is upped for small widths for better visual uniformity across widths;
 477         // (3) deflection somewhat depends on speed, to prevent fast strokes looking
 478         // comparatively smooth and slow ones excessively jittery
 479         tremble_left  = (y1)*dc->tremor * (0.15 + 0.8*width) * (0.35 + 14*Geom::L2(dc->vel));
 480         tremble_right = (y2)*dc->tremor * (0.15 + 0.8*width) * (0.35 + 14*Geom::L2(dc->vel));
 481     }
 482
 483     if ( width < 0.02 * dc->width ) {
 484         width = 0.02 * dc->width;
 485     }
 486
 487     double dezoomify_factor = 0.05 * 1000;
 488     if (!dc->abs_width) {
 489         dezoomify_factor /= SP_EVENT_CONTEXT(dc)->desktop->current_zoom();
 490     }
 491
 492     Geom::Point del_left = dezoomify_factor * (width + tremble_left) * dc->ang;
 493     Geom::Point del_right = dezoomify_factor * (width + tremble_right) * dc->ang;
 494
 495     dc->point1[dc->npoints] = brush + del_left;
 496     dc->point2[dc->npoints] = brush - del_right;
 497
 498     dc->del = 0.5*(del_left + del_right);
 499
 500     dc->npoints++;
 501 }
 502
 503 void
 504 sp_ddc_update_toolbox (SPDesktop *desktop, const gchar *id, double value)
 505 {
 506     desktop->setToolboxAdjustmentValue (id, value);
 507 }
 508
 509 static void
 510 calligraphic_cancel(SPDynaDrawContext *dc)
 511 {
 512     SPDesktop *desktop = SP_EVENT_CONTEXT(dc)->desktop;
 513     dc->dragging = FALSE;
 514     dc->is_drawing = false;
 515     sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate), 0);
 516             /* Remove all temporary line segments */
 517             while (dc->segments) {
 518                 gtk_object_destroy(GTK_OBJECT(dc->segments->data));
 519                 dc->segments = g_slist_remove(dc->segments, dc->segments->data);
 520             }
 521             /* reset accumulated curve */
 522             dc->accumulated->reset();
 523             clear_current(dc);
 524             if (dc->repr) {
 525                 dc->repr = NULL;
 526             }
 527 }
 528
 529
 530 gint
 531 sp_dyna_draw_context_root_handler(SPEventContext *event_context,
 532                                   GdkEvent *event)
 533 {
 534     SPDynaDrawContext *dc = SP_DYNA_DRAW_CONTEXT(event_context);
 535     SPDesktop *desktop = event_context->desktop;
 536
 537     gint ret = FALSE;
 538
 539     switch (event->type) {
 540         case GDK_BUTTON_PRESS:
 541             if (event->button.button == 1 && !event_context->space_panning) {
 542
 543                 SPDesktop *desktop = SP_EVENT_CONTEXT_DESKTOP(dc);
 544
 545                 if (Inkscape::have_viable_layer(desktop, dc->_message_context) == false) {
 546                     return TRUE;
 547                 }
 548
 549                 dc->accumulated->reset();
 550                 if (dc->repr) {
 551                     dc->repr = NULL;
 552                 }
 553
 554                 /* initialize first point */
 555                 dc->npoints = 0;
 556
 557                 sp_canvas_item_grab(SP_CANVAS_ITEM(desktop->acetate),
 558                                     ( GDK_KEY_PRESS_MASK |
 559                                       GDK_BUTTON_RELEASE_MASK |
 560                                       GDK_POINTER_MOTION_MASK |
 561                                       GDK_BUTTON_PRESS_MASK ),
 562                                     NULL,
 563                                     event->button.time);
 564
 565                 ret = TRUE;
 566
 567                 sp_canvas_force_full_redraw_after_interruptions(desktop->canvas, 3);
 568                 dc->is_drawing = true;
 569                 dc->just_started_drawing = true;
 570             }
 571             break;
 572         case GDK_MOTION_NOTIFY:
 573         {
 574             Geom::Point const motion_w(event->motion.x,
 575                                      event->motion.y);
 576             Geom::Point motion_dt(desktop->w2d(motion_w));
 577             sp_dyna_draw_extinput(dc, event);
 578
 579             dc->_message_context->clear();
 580
 581             // for hatching:
 582             double hatch_dist = 0;
 583             Geom::Point hatch_unit_vector(0,0);
 584             Geom::Point nearest(0,0);
 585             Geom::Point pointer(0,0);
 586             Geom::Matrix motion_to_curve(Geom::identity());
 587
 588             if (event->motion.state & GDK_CONTROL_MASK) { // hatching - sense the item
 589
 590                 SPItem *selected = sp_desktop_selection(desktop)->singleItem();
 591                 if (selected && (SP_IS_SHAPE(selected) || SP_IS_TEXT(selected))) {
 592                     // One item selected, and it's a path;
 593                     // let's try to track it as a guide
 594
 595                     if (selected != dc->hatch_item) {
 596                         dc->hatch_item = selected;
 597                         if (dc->hatch_livarot_path)
 598                             delete dc->hatch_livarot_path;
 599                         dc->hatch_livarot_path = Path_for_item (dc->hatch_item, true, true);
 600                         dc->hatch_livarot_path->ConvertWithBackData(0.01);
 601                     }
 602
 603                     // calculate pointer point in the guide item's coords
 604                     motion_to_curve = selected->dt2i_affine() * selected->i2doc_affine();
 605                     pointer = motion_dt * motion_to_curve;
 606
 607                     // calculate the nearest point on the guide path
 608                     boost::optional<Path::cut_position> position = get_nearest_position_on_Path(dc->hatch_livarot_path, pointer);
 609                     nearest = get_point_on_Path(dc->hatch_livarot_path, position->piece, position->t);
 610
 611
 612                     // distance from pointer to nearest
 613                     hatch_dist = Geom::L2(pointer - nearest);
 614                     // unit-length vector
 615                     hatch_unit_vector = (pointer - nearest)/hatch_dist;
 616
 617                     dc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("<b>Guide path selected</b>; start drawing along the guide with <b>Ctrl</b>"));
 618                 } else {
 619                     dc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("<b>Select a guide path</b> to track with <b>Ctrl</b>"));
 620                 }
 621             }
 622
 623             if ( dc->is_drawing && (event->motion.state & GDK_BUTTON1_MASK) && !event_context->space_panning) {
 624                 dc->dragging = TRUE;
 625
 626                 if (event->motion.state & GDK_CONTROL_MASK && dc->hatch_item) { // hatching
 627
 628 #define HATCH_VECTOR_ELEMENTS 12
 629 #define INERTIA_ELEMENTS 24
 630 #define SPEED_ELEMENTS 12
 631 #define SPEED_MIN 0.3
 632 #define SPEED_NORMAL 0.35
 633 #define INERTIA_FORCE 0.5
 634
 635                     // speed is the movement of the nearest point along the guide path, divided by
 636                     // the movement of the pointer at the same period; it is averaged for the last
 637                     // SPEED_ELEMENTS motion events.  Normally, as you track the guide path, speed
 638                     // is about 1, i.e. the nearest point on the path is moved by about the same
 639                     // distance as the pointer. If the speed starts to decrease, we are losing
 640                     // contact with the guide; if it drops below SPEED_MIN, we are on our own and
 641                     // not attracted to guide anymore. Most often this happens when you have
 642                     // tracked to the end of a guide calligraphic stroke and keep moving
 643                     // further. We try to handle this situation gracefully: not stick with the
 644                     // guide forever but let go of it smoothly and without sharp jerks (non-zero
 645                     // mass recommended; with zero mass, jerks are still quite noticeable).
 646
 647                     double speed = 1;
 648                     if (Geom::L2(dc->hatch_last_nearest) != 0) {
 649                         // the distance nearest moved since the last motion event
 650                         double nearest_moved = Geom::L2(nearest - dc->hatch_last_nearest);
 651                         // the distance pointer moved since the last motion event
 652                         double pointer_moved = Geom::L2(pointer - dc->hatch_last_pointer);
 653                         // store them in stacks limited to SPEED_ELEMENTS
 654                         dc->hatch_nearest_past.push_front(nearest_moved);
 655                         if (dc->hatch_nearest_past.size() > SPEED_ELEMENTS)
 656                             dc->hatch_nearest_past.pop_back();
 657                         dc->hatch_pointer_past.push_front(pointer_moved);
 658                         if (dc->hatch_pointer_past.size() > SPEED_ELEMENTS)
 659                             dc->hatch_pointer_past.pop_back();
 660
 661                         // If the stacks are full,
 662                         if (dc->hatch_nearest_past.size() == SPEED_ELEMENTS) {
 663                             // calculate the sums of all stored movements
 664                             double nearest_sum = std::accumulate (dc->hatch_nearest_past.begin(), dc->hatch_nearest_past.end(), 0.0);
 665                             double pointer_sum = std::accumulate (dc->hatch_pointer_past.begin(), dc->hatch_pointer_past.end(), 0.0);
 666                             // and divide to get the speed
 667                             speed = nearest_sum/pointer_sum;
 668                             //g_print ("nearest sum %g  pointer_sum %g  speed %g\n", nearest_sum, pointer_sum, speed);
 669                         }
 670                     }
 671
 672                     if (   dc->hatch_escaped  // already escaped, do not reattach
 673                         || (speed < SPEED_MIN) // stuck; most likely reached end of traced stroke
 674                         || (dc->hatch_spacing > 0 && hatch_dist > 50 * dc->hatch_spacing) // went too far from the guide
 675                         ) {
 676                         // We are NOT attracted to the guide!
 677
 678                         //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);
 679
 680                         // Remember hatch_escaped so we don't get
 681                         // attracted again until the end of this stroke
 682                         dc->hatch_escaped = true;
 683
 684                         if (dc->inertia_vectors.size() >= INERTIA_ELEMENTS/2) { // move by inertia
 685                             Geom::Point moved_past_escape = motion_dt - dc->inertia_vectors.front();
 686                             Geom::Point inertia =
 687                                 dc->inertia_vectors.front() - dc->inertia_vectors.back();
 688
 689                             double dot = Geom::dot (moved_past_escape, inertia);
 690                             dot /= Geom::L2(moved_past_escape) * Geom::L2(inertia);
 691
 692                             if (dot > 0) { // mouse is still moving in approx the same direction
 693                                 Geom::Point should_have_moved =
 694                                     (inertia) * (1/Geom::L2(inertia)) * Geom::L2(moved_past_escape);
 695                                 motion_dt = dc->inertia_vectors.front() +
 696                                     (INERTIA_FORCE * should_have_moved + (1 - INERTIA_FORCE) * moved_past_escape);
 697                             }
 698                         }
 699
 700                     } else {
 701
 702                         // Calculate angle cosine of this vector-to-guide and all past vectors
 703                         // summed, to detect if we accidentally flipped to the other side of the
 704                         // guide
 705                         Geom::Point hatch_vector_accumulated = std::accumulate
 706                             (dc->hatch_vectors.begin(), dc->hatch_vectors.end(), Geom::Point(0,0));
 707                         double dot = Geom::dot (pointer - nearest, hatch_vector_accumulated);
 708                         dot /= Geom::L2(pointer - nearest) * Geom::L2(hatch_vector_accumulated);
 709
 710                         if (dc->hatch_spacing != 0) { // spacing was already set
 711                             double target;
 712                             if (speed > SPEED_NORMAL) {
 713                                 // all ok, strictly obey the spacing
 714                                 target = dc->hatch_spacing;
 715                             } else {
 716                                 // looks like we're starting to lose speed,
 717                                 // so _gradually_ let go attraction to prevent jerks
 718                                 target = (dc->hatch_spacing * speed + hatch_dist * (SPEED_NORMAL - speed))/SPEED_NORMAL;
 719                             }
 720                             if (!IS_NAN(dot) && dot < -0.5) {// flip
 721                                 target = -target;
 722                             }
 723
 724                             // This is the track pointer that we will use instead of the real one
 725                             Geom::Point new_pointer = nearest + target * hatch_unit_vector;
 726
 727                             // some limited feedback: allow persistent pulling to slightly change
 728                             // the spacing
 729                             dc->hatch_spacing += (hatch_dist - dc->hatch_spacing)/3500;
 730
 731                             // return it to the desktop coords
 732                             motion_dt = new_pointer * motion_to_curve.inverse();
 733
 734                             if (speed >= SPEED_NORMAL) {
 735                                 dc->inertia_vectors.push_front(motion_dt);
 736                                 if (dc->inertia_vectors.size() > INERTIA_ELEMENTS)
 737                                     dc->inertia_vectors.pop_back();
 738                             }
 739
 740                         } else {
 741                             // this is the first motion event, set the dist
 742                             dc->hatch_spacing = hatch_dist;
 743                         }
 744
 745                         // remember last points
 746                         dc->hatch_last_pointer = pointer;
 747                         dc->hatch_last_nearest = nearest;
 748
 749                         dc->hatch_vectors.push_front(pointer - nearest);
 750                         if (dc->hatch_vectors.size() > HATCH_VECTOR_ELEMENTS)
 751                             dc->hatch_vectors.pop_back();
 752                     }
 753
 754                     dc->_message_context->set(Inkscape::NORMAL_MESSAGE, dc->hatch_escaped? _("Tracking: <b>connection to guide path lost!</b>") : _("<b>Tracking</b> a guide path"));
 755
 756                 } else {
 757                     dc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("<b>Drawing</b> a calligraphic stroke"));
 758                 }
 759
 760                 if (dc->just_started_drawing) {
 761                     dc->just_started_drawing = false;
 762                     sp_dyna_draw_reset(dc, motion_dt);
 763                 }
 764
 765                 if (!sp_dyna_draw_apply(dc, motion_dt)) {
 766                     ret = TRUE;
 767                     break;
 768                 }
 769
 770                 if ( dc->cur != dc->last ) {
 771                     sp_dyna_draw_brush(dc);
 772                     g_assert( dc->npoints > 0 );
 773                     fit_and_split(dc, FALSE);
 774                 }
 775                 ret = TRUE;
 776             }
 777
 778             // Draw the hatching circle if necessary
 779             if (event->motion.state & GDK_CONTROL_MASK) {
 780                 if (dc->hatch_spacing == 0 && hatch_dist != 0) {
 781                     // Haven't set spacing yet: gray, center free, update radius live
 782                     Geom::Point c = desktop->w2d(motion_w);
 783                     Geom::Matrix const sm (Geom::Scale(hatch_dist, hatch_dist) * Geom::Translate(c));
 784                     sp_canvas_item_affine_absolute(dc->hatch_area, sm);
 785                     sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(dc->hatch_area), 0x7f7f7fff, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 786                     sp_canvas_item_show(dc->hatch_area);
 787                 } else if (dc->dragging && !dc->hatch_escaped) {
 788                     // Tracking: green, center snapped, fixed radius
 789                     Geom::Point c = motion_dt;
 790                     Geom::Matrix const sm (Geom::Scale(dc->hatch_spacing, dc->hatch_spacing) * Geom::Translate(c));
 791                     sp_canvas_item_affine_absolute(dc->hatch_area, sm);
 792                     sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(dc->hatch_area), 0x00FF00ff, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 793                     sp_canvas_item_show(dc->hatch_area);
 794                 } else if (dc->dragging && dc->hatch_escaped) {
 795                     // Tracking escaped: red, center free, fixed radius
 796                     Geom::Point c = motion_dt;
 797                     Geom::Matrix const sm (Geom::Scale(dc->hatch_spacing, dc->hatch_spacing) * Geom::Translate(c));
 798
 799                     sp_canvas_item_affine_absolute(dc->hatch_area, sm);
 800                     sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(dc->hatch_area), 0xFF0000ff, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 801                     sp_canvas_item_show(dc->hatch_area);
 802                 } else {
 803                     // Not drawing but spacing set: gray, center snapped, fixed radius
 804                     Geom::Point c = (nearest + dc->hatch_spacing * hatch_unit_vector) * motion_to_curve.inverse();
 805                     if (!IS_NAN(c[Geom::X]) && !IS_NAN(c[Geom::Y])) {
 806                         Geom::Matrix const sm (Geom::Scale(dc->hatch_spacing, dc->hatch_spacing) * Geom::Translate(c));
 807                         sp_canvas_item_affine_absolute(dc->hatch_area, sm);
 808                         sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(dc->hatch_area), 0x7f7f7fff, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 809                         sp_canvas_item_show(dc->hatch_area);
 810                     }
 811                 }
 812             } else {
 813                 sp_canvas_item_hide(dc->hatch_area);
 814             }
 815         }
 816         break;
 817
 818
 819     case GDK_BUTTON_RELEASE:
 820     {
 821         Geom::Point const motion_w(event->button.x, event->button.y);
 822         Geom::Point const motion_dt(desktop->w2d(motion_w));
 823
 824         sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate), event->button.time);
 825         sp_canvas_end_forced_full_redraws(desktop->canvas);
 826         dc->is_drawing = false;
 827
 828         if (dc->dragging && event->button.button == 1 && !event_context->space_panning) {
 829             dc->dragging = FALSE;
 830
 831             sp_dyna_draw_apply(dc, motion_dt);
 832
 833             /* Remove all temporary line segments */
 834             while (dc->segments) {
 835                 gtk_object_destroy(GTK_OBJECT(dc->segments->data));
 836                 dc->segments = g_slist_remove(dc->segments, dc->segments->data);
 837             }
 838
 839             /* Create object */
 840             fit_and_split(dc, TRUE);
 841             if (accumulate_calligraphic(dc))
 842                 set_to_accumulated(dc, event->button.state & GDK_SHIFT_MASK, event->button.state & GDK_MOD1_MASK); // performs document_done
 843             else
 844                 g_warning ("Failed to create path: invalid data in dc->cal1 or dc->cal2");
 845
 846             /* reset accumulated curve */
 847             dc->accumulated->reset();
 848
 849             clear_current(dc);
 850             if (dc->repr) {
 851                 dc->repr = NULL;
 852             }
 853
 854             if (!dc->hatch_pointer_past.empty()) dc->hatch_pointer_past.clear();
 855             if (!dc->hatch_nearest_past.empty()) dc->hatch_nearest_past.clear();
 856             if (!dc->inertia_vectors.empty()) dc->inertia_vectors.clear();
 857             if (!dc->hatch_vectors.empty()) dc->hatch_vectors.clear();
 858             dc->hatch_last_nearest = Geom::Point(0,0);
 859             dc->hatch_last_pointer = Geom::Point(0,0);
 860             dc->hatch_escaped = false;
 861             dc->hatch_item = NULL;
 862             dc->hatch_livarot_path = NULL;
 863             dc->just_started_drawing = false;
 864
 865             if (dc->hatch_spacing != 0 && !dc->keep_selected) {
 866                 // we do not select the newly drawn path, so increase spacing by step
 867                 if (dc->hatch_spacing_step == 0) {
 868                     dc->hatch_spacing_step = dc->hatch_spacing;
 869                 }
 870                 dc->hatch_spacing += dc->hatch_spacing_step;
 871             }
 872
 873             dc->_message_context->clear();
 874             ret = TRUE;
 875         }
 876         break;
 877     }
 878
 879     case GDK_KEY_PRESS:
 880         switch (get_group0_keyval (&event->key)) {
 881         case GDK_Up:
 882         case GDK_KP_Up:
 883             if (!MOD__CTRL_ONLY) {
 884                 dc->angle += 5.0;
 885                 if (dc->angle > 90.0)
 886                     dc->angle = 90.0;
 887                 sp_ddc_update_toolbox (desktop, "calligraphy-angle", dc->angle);
 888                 ret = TRUE;
 889             }
 890             break;
 891         case GDK_Down:
 892         case GDK_KP_Down:
 893             if (!MOD__CTRL_ONLY) {
 894                 dc->angle -= 5.0;
 895                 if (dc->angle < -90.0)
 896                     dc->angle = -90.0;
 897                 sp_ddc_update_toolbox (desktop, "calligraphy-angle", dc->angle);
 898                 ret = TRUE;
 899             }
 900             break;
 901         case GDK_Right:
 902         case GDK_KP_Right:
 903             if (!MOD__CTRL_ONLY) {
 904                 dc->width += 0.01;
 905                 if (dc->width > 1.0)
 906                     dc->width = 1.0;
 907                 sp_ddc_update_toolbox (desktop, "altx-calligraphy", dc->width * 100); // the same spinbutton is for alt+x
 908                 ret = TRUE;
 909             }
 910             break;
 911         case GDK_Left:
 912         case GDK_KP_Left:
 913             if (!MOD__CTRL_ONLY) {
 914                 dc->width -= 0.01;
 915                 if (dc->width < 0.01)
 916                     dc->width = 0.01;
 917                 sp_ddc_update_toolbox (desktop, "altx-calligraphy", dc->width * 100);
 918                 ret = TRUE;
 919             }
 920             break;
 921         case GDK_Home:
 922         case GDK_KP_Home:
 923             dc->width = 0.01;
 924             sp_ddc_update_toolbox (desktop, "altx-calligraphy", dc->width * 100);
 925             ret = TRUE;
 926             break;
 927         case GDK_End:
 928         case GDK_KP_End:
 929             dc->width = 1.0;
 930             sp_ddc_update_toolbox (desktop, "altx-calligraphy", dc->width * 100);
 931             ret = TRUE;
 932             break;
 933         case GDK_x:
 934         case GDK_X:
 935             if (MOD__ALT_ONLY) {
 936                 desktop->setToolboxFocusTo ("altx-calligraphy");
 937                 ret = TRUE;
 938             }
 939             break;
 940         case GDK_Escape:
 941             if (dc->is_drawing) {
 942                 // if drawing, cancel, otherwise pass it up for deselecting
 943                 calligraphic_cancel (dc);
 944                 ret = TRUE;
 945             }
 946             break;
 947         case GDK_z:
 948         case GDK_Z:
 949             if (MOD__CTRL_ONLY && dc->is_drawing) {
 950                 // if drawing, cancel, otherwise pass it up for undo
 951                 calligraphic_cancel (dc);
 952                 ret = TRUE;
 953             }
 954             break;
 955         default:
 956             break;
 957         }
 958         break;
 959
 960     case GDK_KEY_RELEASE:
 961         switch (get_group0_keyval(&event->key)) {
 962             case GDK_Control_L:
 963             case GDK_Control_R:
 964                 dc->_message_context->clear();
 965                 dc->hatch_spacing = 0;
 966                 dc->hatch_spacing_step = 0;
 967                 break;
 968             default:
 969                 break;
 970         }
 971
 972     default:
 973         break;
 974     }
 975
 976     if (!ret) {
 977         if (((SPEventContextClass *) dd_parent_class)->root_handler) {
 978             ret = ((SPEventContextClass *) dd_parent_class)->root_handler(event_context, event);
 979         }
 980     }
 981
 982     return ret;
 983 }
 984
 985
 986 static void
 987 clear_current(SPDynaDrawContext *dc)
 988 {
 989     /* reset bpath */
 990     sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(dc->currentshape), NULL);
 991     /* reset curve */
 992     dc->currentcurve->reset();
 993     dc->cal1->reset();
 994     dc->cal2->reset();
 995     /* reset points */
 996     dc->npoints = 0;
 997 }
 998
 999 static void
1000 set_to_accumulated(SPDynaDrawContext *dc, bool unionize, bool subtract)
1001 {
1002     SPDesktop *desktop = SP_EVENT_CONTEXT(dc)->desktop;
1003
1004     if (!dc->accumulated->is_empty()) {
1005         if (!dc->repr) {
1006             /* Create object */
1007             Inkscape::XML::Document *xml_doc = desktop->doc()->getReprDoc();
1008             Inkscape::XML::Node *repr = xml_doc->createElement("svg:path");
1009
1010             /* Set style */
1011             sp_desktop_apply_style_tool (desktop, repr, "/tools/calligraphic", false);
1012
1013             dc->repr = repr;
1014
1015             SPItem *item=SP_ITEM(desktop->currentLayer()->appendChildRepr(dc->repr));
1016             Inkscape::GC::release(dc->repr);
1017             item->transform = SP_ITEM(desktop->currentLayer())->i2doc_affine().inverse();
1018             item->updateRepr();
1019         }
1020         Geom::PathVector pathv = dc->accumulated->get_pathvector() * desktop->dt2doc();
1021         gchar *str = sp_svg_write_path(pathv);
1022         g_assert( str != NULL );
1023         dc->repr->setAttribute("d", str);
1024         g_free(str);
1025
1026         if (unionize) {
1027             sp_desktop_selection(desktop)->add(dc->repr);
1028             sp_selected_path_union_skip_undo(desktop);
1029         } else if (subtract) {
1030             sp_desktop_selection(desktop)->add(dc->repr);
1031             sp_selected_path_diff_skip_undo(desktop);
1032         } else {
1033             if (dc->keep_selected) {
1034                 sp_desktop_selection(desktop)->set(dc->repr);
1035             }
1036         }
1037
1038     } else {
1039         if (dc->repr) {
1040             sp_repr_unparent(dc->repr);
1041         }
1042         dc->repr = NULL;
1043     }
1044
1045     DocumentUndo::done(sp_desktop_document(desktop), SP_VERB_CONTEXT_CALLIGRAPHIC,
1046                        _("Draw calligraphic stroke"));
1047 }
1048
1049 static void
1050 add_cap(SPCurve *curve,
1051         Geom::Point const &from,
1052         Geom::Point const &to,
1053         double rounding)
1054 {
1055     if (Geom::L2( to - from ) > DYNA_EPSILON) {
1056         Geom::Point vel = rounding * Geom::rot90( to - from ) / sqrt(2.0);
1057         double mag = Geom::L2(vel);
1058
1059         Geom::Point v = mag * Geom::rot90( to - from ) / Geom::L2( to - from );
1060         curve->curveto(from + v, to + v, to);
1061     }
1062 }
1063
1064 static bool
1065 accumulate_calligraphic(SPDynaDrawContext *dc)
1066 {
1067         if (
1068             dc->cal1->is_empty() ||
1069             dc->cal2->is_empty() ||
1070             (dc->cal1->get_segment_count() <= 0) ||
1071             dc->cal1->first_path()->closed()
1072             ) {
1073             dc->cal1->reset();
1074             dc->cal2->reset();
1075             return false; // failure
1076         }
1077
1078         SPCurve *rev_cal2 = dc->cal2->create_reverse();
1079         if (
1080             (rev_cal2->get_segment_count() <= 0) ||
1081             rev_cal2->first_path()->closed()
1082             ) {
1083             rev_cal2->unref();
1084             dc->cal1->reset();
1085             dc->cal2->reset();
1086             return false; // failure
1087         }
1088
1089         Geom::CubicBezier const * dc_cal1_firstseg  = dynamic_cast<Geom::CubicBezier const *>( dc->cal1->first_segment() );
1090         Geom::CubicBezier const * rev_cal2_firstseg = dynamic_cast<Geom::CubicBezier const *>( rev_cal2->first_segment() );
1091         Geom::CubicBezier const * dc_cal1_lastseg   = dynamic_cast<Geom::CubicBezier const *>( dc->cal1->last_segment() );
1092         Geom::CubicBezier const * rev_cal2_lastseg  = dynamic_cast<Geom::CubicBezier const *>( rev_cal2->last_segment() );
1093
1094         if (
1095             !dc_cal1_firstseg ||
1096             !rev_cal2_firstseg ||
1097             !dc_cal1_lastseg ||
1098             !rev_cal2_lastseg
1099             ) {
1100             rev_cal2->unref();
1101             dc->cal1->reset();
1102             dc->cal2->reset();
1103             return false; // failure
1104         }
1105
1106         dc->accumulated->reset(); /*  Is this required ?? */
1107
1108         dc->accumulated->append(dc->cal1, false);
1109
1110         add_cap(dc->accumulated, (*dc_cal1_lastseg)[3], (*rev_cal2_firstseg)[0], dc->cap_rounding);
1111
1112         dc->accumulated->append(rev_cal2, true);
1113
1114         add_cap(dc->accumulated, (*rev_cal2_lastseg)[3], (*dc_cal1_firstseg)[0], dc->cap_rounding);
1115
1116         dc->accumulated->closepath();
1117
1118         rev_cal2->unref();
1119
1120         dc->cal1->reset();
1121         dc->cal2->reset();
1122
1123         return true; // success
1124 }
1125
1126 static double square(double const x)
1127 {
1128     return x * x;
1129 }
1130
1131 static void
1132 fit_and_split(SPDynaDrawContext *dc, gboolean release)
1133 {
1134     SPDesktop *desktop = SP_EVENT_CONTEXT(dc)->desktop;
1135
1136     double const tolerance_sq = square( desktop->w2d().descrim() * TOLERANCE_CALLIGRAPHIC );
1137
1138 #ifdef DYNA_DRAW_VERBOSE
1139     g_print("[F&S:R=%c]", release?'T':'F');
1140 #endif
1141
1142     if (!( dc->npoints > 0 && dc->npoints < SAMPLING_SIZE ))
1143         return; // just clicked
1144
1145     if ( dc->npoints == SAMPLING_SIZE - 1 || release ) {
1146 #define BEZIER_SIZE       4
1147 #define BEZIER_MAX_BEZIERS  8
1148 #define BEZIER_MAX_LENGTH ( BEZIER_SIZE * BEZIER_MAX_BEZIERS )
1149
1150 #ifdef DYNA_DRAW_VERBOSE
1151         g_print("[F&S:#] dc->npoints:%d, release:%s\n",
1152                 dc->npoints, release ? "TRUE" : "FALSE");
1153 #endif
1154
1155         /* Current calligraphic */
1156         if ( dc->cal1->is_empty() || dc->cal2->is_empty() ) {
1157             /* dc->npoints > 0 */
1158             /* g_print("calligraphics(1|2) reset\n"); */
1159             dc->cal1->reset();
1160             dc->cal2->reset();
1161
1162             dc->cal1->moveto(dc->point1[0]);
1163             dc->cal2->moveto(dc->point2[0]);
1164         }
1165
1166         Geom::Point b1[BEZIER_MAX_LENGTH];
1167         gint const nb1 = Geom::bezier_fit_cubic_r(b1, dc->point1, dc->npoints,
1168                                                tolerance_sq, BEZIER_MAX_BEZIERS);
1169         g_assert( nb1 * BEZIER_SIZE <= gint(G_N_ELEMENTS(b1)) );
1170
1171         Geom::Point b2[BEZIER_MAX_LENGTH];
1172         gint const nb2 = Geom::bezier_fit_cubic_r(b2, dc->point2, dc->npoints,
1173                                                tolerance_sq, BEZIER_MAX_BEZIERS);
1174         g_assert( nb2 * BEZIER_SIZE <= gint(G_N_ELEMENTS(b2)) );
1175
1176         if ( nb1 != -1 && nb2 != -1 ) {
1177             /* Fit and draw and reset state */
1178 #ifdef DYNA_DRAW_VERBOSE
1179             g_print("nb1:%d nb2:%d\n", nb1, nb2);
1180 #endif
1181             /* CanvasShape */
1182             if (! release) {
1183                 dc->currentcurve->reset();
1184                 dc->currentcurve->moveto(b1[0]);
1185                 for (Geom::Point *bp1 = b1; bp1 < b1 + BEZIER_SIZE * nb1; bp1 += BEZIER_SIZE) {
1186                     dc->currentcurve->curveto(bp1[1], bp1[2], bp1[3]);
1187                 }
1188                 dc->currentcurve->lineto(b2[BEZIER_SIZE*(nb2-1) + 3]);
1189                 for (Geom::Point *bp2 = b2 + BEZIER_SIZE * ( nb2 - 1 ); bp2 >= b2; bp2 -= BEZIER_SIZE) {
1190                     dc->currentcurve->curveto(bp2[2], bp2[1], bp2[0]);
1191                 }
1192                 // FIXME: dc->segments is always NULL at this point??
1193                 if (!dc->segments) { // first segment
1194                     add_cap(dc->currentcurve, b2[0], b1[0], dc->cap_rounding);
1195                 }
1196                 dc->currentcurve->closepath();
1197                 sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(dc->currentshape), dc->currentcurve);
1198             }
1199
1200             /* Current calligraphic */
1201             for (Geom::Point *bp1 = b1; bp1 < b1 + BEZIER_SIZE * nb1; bp1 += BEZIER_SIZE) {
1202                 dc->cal1->curveto(bp1[1], bp1[2], bp1[3]);
1203             }
1204             for (Geom::Point *bp2 = b2; bp2 < b2 + BEZIER_SIZE * nb2; bp2 += BEZIER_SIZE) {
1205                 dc->cal2->curveto(bp2[1], bp2[2], bp2[3]);
1206             }
1207         } else {
1208             /* fixme: ??? */
1209 #ifdef DYNA_DRAW_VERBOSE
1210             g_print("[fit_and_split] failed to fit-cubic.\n");
1211 #endif
1212             draw_temporary_box(dc);
1213
1214             for (gint i = 1; i < dc->npoints; i++) {
1215                 dc->cal1->lineto(dc->point1[i]);
1216             }
1217             for (gint i = 1; i < dc->npoints; i++) {
1218                 dc->cal2->lineto(dc->point2[i]);
1219             }
1220         }
1221
1222         /* Fit and draw and copy last point */
1223 #ifdef DYNA_DRAW_VERBOSE
1224         g_print("[%d]Yup\n", dc->npoints);
1225 #endif
1226         if (!release) {
1227             g_assert(!dc->currentcurve->is_empty());
1228
1229             SPCanvasItem *cbp = sp_canvas_item_new(sp_desktop_sketch(desktop),
1230                                                    SP_TYPE_CANVAS_BPATH,
1231                                                    NULL);
1232             SPCurve *curve = dc->currentcurve->copy();
1233             sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH (cbp), curve);
1234             curve->unref();
1235
1236             guint32 fillColor = sp_desktop_get_color_tool (desktop, "/tools/calligraphic", true);
1237             //guint32 strokeColor = sp_desktop_get_color_tool (desktop, "/tools/calligraphic", false);
1238             double opacity = sp_desktop_get_master_opacity_tool (desktop, "/tools/calligraphic");
1239             double fillOpacity = sp_desktop_get_opacity_tool (desktop, "/tools/calligraphic", true);
1240             //double strokeOpacity = sp_desktop_get_opacity_tool (desktop, "/tools/calligraphic", false);
1241             sp_canvas_bpath_set_fill(SP_CANVAS_BPATH(cbp), ((fillColor & 0xffffff00) | SP_COLOR_F_TO_U(opacity*fillOpacity)), SP_WIND_RULE_EVENODD);
1242             //on second thougtht don't do stroke yet because we don't have stoke-width yet and because stoke appears between segments while drawing
1243             //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);
1244             sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(cbp), 0x00000000, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
1245             /* fixme: Cannot we cascade it to root more clearly? */
1246             g_signal_connect(G_OBJECT(cbp), "event", G_CALLBACK(sp_desktop_root_handler), desktop);
1247
1248             dc->segments = g_slist_prepend(dc->segments, cbp);
1249         }
1250
1251         dc->point1[0] = dc->point1[dc->npoints - 1];
1252         dc->point2[0] = dc->point2[dc->npoints - 1];
1253         dc->npoints = 1;
1254     } else {
1255         draw_temporary_box(dc);
1256     }
1257 }
1258
1259 static void
1260 draw_temporary_box(SPDynaDrawContext *dc)
1261 {
1262     dc->currentcurve->reset();
1263
1264     dc->currentcurve->moveto(dc->point2[dc->npoints-1]);
1265     for (gint i = dc->npoints-2; i >= 0; i--) {
1266         dc->currentcurve->lineto(dc->point2[i]);
1267     }
1268     for (gint i = 0; i < dc->npoints; i++) {
1269         dc->currentcurve->lineto(dc->point1[i]);
1270     }
1271
1272     if (dc->npoints >= 2) {
1273         add_cap(dc->currentcurve, dc->point1[dc->npoints-1], dc->point2[dc->npoints-1], dc->cap_rounding);
1274     }
1275
1276     dc->currentcurve->closepath();
1277     sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(dc->currentshape), dc->currentcurve);
1278 }
1279
1280 /*
1281   Local Variables:
1282   mode:c++
1283   c-file-style:"stroustrup"
1284   c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
1285   indent-tabs-mode:nil
1286   fill-column:99
1287   End:
1288 */
1289 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :