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     ddc->hatch_last_nearest = Geom::Point(0,0);
 157     ddc->hatch_last_pointer = Geom::Point(0,0);
 158     ddc->hatch_vector_accumulated = Geom::Point(0,0);
 159     ddc->hatch_escaped = false;
 160     ddc->hatch_area = NULL;
 161     ddc->hatch_item = NULL;
 162     ddc->hatch_livarot_path = NULL;
 163
 164     ddc->trace_bg = false;
 165 }
 166
 167 static void
 168 sp_dyna_draw_context_dispose(GObject *object)
 169 {
 170     SPDynaDrawContext *ddc = SP_DYNA_DRAW_CONTEXT(object);
 171
 172     if (ddc->hatch_area) {
 173         gtk_object_destroy(GTK_OBJECT(ddc->hatch_area));
 174         ddc->hatch_area = NULL;
 175     }
 176
 177
 178     G_OBJECT_CLASS(dd_parent_class)->dispose(object);
 179
 180     ddc->hatch_pointer_past.~list();
 181     ddc->hatch_nearest_past.~list();
 182 }
 183
 184 static void
 185 sp_dyna_draw_context_setup(SPEventContext *ec)
 186 {
 187     SPDynaDrawContext *ddc = SP_DYNA_DRAW_CONTEXT(ec);
 188
 189     if (((SPEventContextClass *) dd_parent_class)->setup)
 190         ((SPEventContextClass *) dd_parent_class)->setup(ec);
 191
 192     ddc->accumulated = new SPCurve();
 193     ddc->currentcurve = new SPCurve();
 194
 195     ddc->cal1 = new SPCurve();
 196     ddc->cal2 = new SPCurve();
 197
 198     ddc->currentshape = sp_canvas_item_new(sp_desktop_sketch(ec->desktop), SP_TYPE_CANVAS_BPATH, NULL);
 199     sp_canvas_bpath_set_fill(SP_CANVAS_BPATH(ddc->currentshape), DDC_RED_RGBA, SP_WIND_RULE_EVENODD);
 200     sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(ddc->currentshape), 0x00000000, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 201     /* fixme: Cannot we cascade it to root more clearly? */
 202     g_signal_connect(G_OBJECT(ddc->currentshape), "event", G_CALLBACK(sp_desktop_root_handler), ec->desktop);
 203
 204     {
 205         /* 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) */
 206         SPCurve *c = new SPCurve();
 207         const double C1 = 0.552;
 208         c->moveto(-1,0);
 209         c->curveto(-1, C1, -C1, 1, 0, 1 );
 210         c->curveto(C1, 1, 1, C1, 1, 0 );
 211         c->curveto(1, -C1, C1, -1, 0, -1 );
 212         c->curveto(-C1, -1, -1, -C1, -1, 0 );
 213         c->closepath();
 214         ddc->hatch_area = sp_canvas_bpath_new(sp_desktop_controls(ec->desktop), c);
 215         c->unref();
 216         sp_canvas_bpath_set_fill(SP_CANVAS_BPATH(ddc->hatch_area), 0x00000000,(SPWindRule)0);
 217         sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(ddc->hatch_area), 0x0000007f, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 218         sp_canvas_item_hide(ddc->hatch_area);
 219     }
 220
 221     sp_event_context_read(ec, "mass");
 222     sp_event_context_read(ec, "wiggle");
 223     sp_event_context_read(ec, "angle");
 224     sp_event_context_read(ec, "width");
 225     sp_event_context_read(ec, "thinning");
 226     sp_event_context_read(ec, "tremor");
 227     sp_event_context_read(ec, "flatness");
 228     sp_event_context_read(ec, "tracebackground");
 229     sp_event_context_read(ec, "usepressure");
 230     sp_event_context_read(ec, "usetilt");
 231     sp_event_context_read(ec, "abs_width");
 232     sp_event_context_read(ec, "keep_selected");
 233     sp_event_context_read(ec, "cap_rounding");
 234
 235     ddc->is_drawing = false;
 236     ddc->_message_context = new Inkscape::MessageContext((ec->desktop)->messageStack());
 237
 238     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 239     if (prefs->getBool("/tools/calligraphic/selcue")) {
 240         ec->enableSelectionCue();
 241     }
 242 }
 243
 244 static void
 245 sp_dyna_draw_context_set(SPEventContext *ec, Inkscape::Preferences::Entry *val)
 246 {
 247     SPDynaDrawContext *ddc = SP_DYNA_DRAW_CONTEXT(ec);
 248     Glib::ustring path = val->getEntryName();
 249
 250     if (path == "tracebackground") {
 251         ddc->trace_bg = val->getBool();
 252     } else if (path == "keep_selected") {
 253         ddc->keep_selected = val->getBool();
 254     } else {
 255         //pass on up to parent class to handle common attributes.
 256         if ( dd_parent_class->set ) {
 257             dd_parent_class->set(ec, val);
 258         }
 259     }
 260
 261     //g_print("DDC: %g %g %g %g\n", ddc->mass, ddc->drag, ddc->angle, ddc->width);
 262 }
 263
 264 static double
 265 flerp(double f0, double f1, double p)
 266 {
 267     return f0 + ( f1 - f0 ) * p;
 268 }
 269
 270 /* Get normalized point */
 271 static Geom::Point
 272 sp_dyna_draw_get_npoint(SPDynaDrawContext const *dc, Geom::Point v)
 273 {
 274     Geom::Rect drect = SP_EVENT_CONTEXT(dc)->desktop->get_display_area();
 275     double const max = MAX ( drect.dimensions()[Geom::X], drect.dimensions()[Geom::Y] );
 276     return Geom::Point(( v[Geom::X] - drect.min()[Geom::X] ) / max,  ( v[Geom::Y] - drect.min()[Geom::Y] ) / max);
 277 }
 278
 279 /* Get view point */
 280 static Geom::Point
 281 sp_dyna_draw_get_vpoint(SPDynaDrawContext const *dc, Geom::Point n)
 282 {
 283     Geom::Rect drect = SP_EVENT_CONTEXT(dc)->desktop->get_display_area();
 284     double const max = MAX ( drect.dimensions()[Geom::X], drect.dimensions()[Geom::Y] );
 285     return Geom::Point(n[Geom::X] * max + drect.min()[Geom::X], n[Geom::Y] * max + drect.min()[Geom::Y]);
 286 }
 287
 288 static void
 289 sp_dyna_draw_reset(SPDynaDrawContext *dc, Geom::Point p)
 290 {
 291     dc->last = dc->cur = sp_dyna_draw_get_npoint(dc, p);
 292     dc->vel = Geom::Point(0,0);
 293     dc->vel_max = 0;
 294     dc->acc = Geom::Point(0,0);
 295     dc->ang = Geom::Point(0,0);
 296     dc->del = Geom::Point(0,0);
 297 }
 298
 299 static void
 300 sp_dyna_draw_extinput(SPDynaDrawContext *dc, GdkEvent *event)
 301 {
 302     if (gdk_event_get_axis (event, GDK_AXIS_PRESSURE, &dc->pressure))
 303         dc->pressure = CLAMP (dc->pressure, DDC_MIN_PRESSURE, DDC_MAX_PRESSURE);
 304     else
 305         dc->pressure = DDC_DEFAULT_PRESSURE;
 306
 307     if (gdk_event_get_axis (event, GDK_AXIS_XTILT, &dc->xtilt))
 308         dc->xtilt = CLAMP (dc->xtilt, DDC_MIN_TILT, DDC_MAX_TILT);
 309     else
 310         dc->xtilt = DDC_DEFAULT_TILT;
 311
 312     if (gdk_event_get_axis (event, GDK_AXIS_YTILT, &dc->ytilt))
 313         dc->ytilt = CLAMP (dc->ytilt, DDC_MIN_TILT, DDC_MAX_TILT);
 314     else
 315         dc->ytilt = DDC_DEFAULT_TILT;
 316 }
 317
 318
 319 static gboolean
 320 sp_dyna_draw_apply(SPDynaDrawContext *dc, Geom::Point p)
 321 {
 322     Geom::Point n = sp_dyna_draw_get_npoint(dc, p);
 323
 324     /* Calculate mass and drag */
 325     double const mass = flerp(1.0, 160.0, dc->mass);
 326     double const drag = flerp(0.0, 0.5, dc->drag * dc->drag);
 327
 328     /* Calculate force and acceleration */
 329     Geom::Point force = n - dc->cur;
 330
 331     // If force is below the absolute threshold DYNA_EPSILON,
 332     // or we haven't yet reached DYNA_VEL_START (i.e. at the beginning of stroke)
 333     // _and_ the force is below the (higher) DYNA_EPSILON_START threshold,
 334     // discard this move.
 335     // This prevents flips, blobs, and jerks caused by microscopic tremor of the tablet pen,
 336     // especially bothersome at the start of the stroke where we don't yet have the inertia to
 337     // smooth them out.
 338     if ( Geom::L2(force) < DYNA_EPSILON || (dc->vel_max < DYNA_VEL_START && Geom::L2(force) < DYNA_EPSILON_START)) {
 339         return FALSE;
 340     }
 341
 342     dc->acc = force / mass;
 343
 344     /* Calculate new velocity */
 345     dc->vel += dc->acc;
 346
 347     if (Geom::L2(dc->vel) > dc->vel_max)
 348         dc->vel_max = Geom::L2(dc->vel);
 349
 350     /* Calculate angle of drawing tool */
 351
 352     double a1;
 353     if (dc->usetilt) {
 354         // 1a. calculate nib angle from input device tilt:
 355         gdouble length = std::sqrt(dc->xtilt*dc->xtilt + dc->ytilt*dc->ytilt);;
 356
 357         if (length > 0) {
 358             Geom::Point ang1 = Geom::Point(dc->ytilt/length, dc->xtilt/length);
 359             a1 = atan2(ang1);
 360         }
 361         else
 362             a1 = 0.0;
 363     }
 364     else {
 365         // 1b. fixed dc->angle (absolutely flat nib):
 366         double const radians = ( (dc->angle - 90) / 180.0 ) * M_PI;
 367         Geom::Point ang1 = Geom::Point(-sin(radians),  cos(radians));
 368         a1 = atan2(ang1);
 369     }
 370
 371     // 2. perpendicular to dc->vel (absolutely non-flat nib):
 372     gdouble const mag_vel = Geom::L2(dc->vel);
 373     if ( mag_vel < DYNA_EPSILON ) {
 374         return FALSE;
 375     }
 376     Geom::Point ang2 = Geom::rot90(dc->vel) / mag_vel;
 377
 378     // 3. Average them using flatness parameter:
 379     // calculate angles
 380     double a2 = atan2(ang2);
 381     // flip a2 to force it to be in the same half-circle as a1
 382     bool flipped = false;
 383     if (fabs (a2-a1) > 0.5*M_PI) {
 384         a2 += M_PI;
 385         flipped = true;
 386     }
 387     // normalize a2
 388     if (a2 > M_PI)
 389         a2 -= 2*M_PI;
 390     if (a2 < -M_PI)
 391         a2 += 2*M_PI;
 392     // find the flatness-weighted bisector angle, unflip if a2 was flipped
 393     // FIXME: when dc->vel is oscillating around the fixed angle, the new_ang flips back and forth. How to avoid this?
 394     double new_ang = a1 + (1 - dc->flatness) * (a2 - a1) - (flipped? M_PI : 0);
 395
 396     // Try to detect a sudden flip when the new angle differs too much from the previous for the
 397     // current velocity; in that case discard this move
 398     double angle_delta = Geom::L2(Geom::Point (cos (new_ang), sin (new_ang)) - dc->ang);
 399     if ( angle_delta / Geom::L2(dc->vel) > 4000 ) {
 400         return FALSE;
 401     }
 402
 403     // convert to point
 404     dc->ang = Geom::Point (cos (new_ang), sin (new_ang));
 405
 406 //    g_print ("force %g  acc %g  vel_max %g  vel %g  a1 %g  a2 %g  new_ang %g\n", NR::L2(force), NR::L2(dc->acc), dc->vel_max, NR::L2(dc->vel), a1, a2, new_ang);
 407
 408     /* Apply drag */
 409     dc->vel *= 1.0 - drag;
 410
 411     /* Update position */
 412     dc->last = dc->cur;
 413     dc->cur += dc->vel;
 414
 415     return TRUE;
 416 }
 417
 418 static void
 419 sp_dyna_draw_brush(SPDynaDrawContext *dc)
 420 {
 421     g_assert( dc->npoints >= 0 && dc->npoints < SAMPLING_SIZE );
 422
 423     // How much velocity thins strokestyle
 424     double vel_thin = flerp (0, 160, dc->vel_thin);
 425
 426     // Influence of pressure on thickness
 427     double pressure_thick = (dc->usepressure ? dc->pressure : 1.0);
 428
 429     // get the real brush point, not the same as pointer (affected by hatch tracking and/or mass
 430     // drag)
 431     Geom::Point brush = sp_dyna_draw_get_vpoint(dc, dc->cur);
 432     Geom::Point brush_w = SP_EVENT_CONTEXT(dc)->desktop->d2w(brush);
 433
 434     double trace_thick = 1;
 435     if (dc->trace_bg) {
 436         // pick single pixel
 437         NRPixBlock pb;
 438         int x = (int) floor(brush_w[Geom::X]);
 439         int y = (int) floor(brush_w[Geom::Y]);
 440         nr_pixblock_setup_fast(&pb, NR_PIXBLOCK_MODE_R8G8B8A8P, x, y, x+1, y+1, TRUE);
 441         sp_canvas_arena_render_pixblock(SP_CANVAS_ARENA(sp_desktop_drawing(SP_EVENT_CONTEXT(dc)->desktop)), &pb);
 442         const unsigned char *s = NR_PIXBLOCK_PX(&pb);
 443         double R = s[0] / 255.0;
 444         double G = s[1] / 255.0;
 445         double B = s[2] / 255.0;
 446         double A = s[3] / 255.0;
 447         double max = MAX (MAX (R, G), B);
 448         double min = MIN (MIN (R, G), B);
 449         double L = A * (max + min)/2 + (1 - A); // blend with white bg
 450         trace_thick = 1 - L;
 451         //g_print ("L %g thick %g\n", L, trace_thick);
 452     }
 453
 454     double width = (pressure_thick * trace_thick - vel_thin * Geom::L2(dc->vel)) * dc->width;
 455
 456     double tremble_left = 0, tremble_right = 0;
 457     if (dc->tremor > 0) {
 458         // obtain two normally distributed random variables, using polar Box-Muller transform
 459         double x1, x2, w, y1, y2;
 460         do {
 461             x1 = 2.0 * g_random_double_range(0,1) - 1.0;
 462             x2 = 2.0 * g_random_double_range(0,1) - 1.0;
 463             w = x1 * x1 + x2 * x2;
 464         } while ( w >= 1.0 );
 465         w = sqrt( (-2.0 * log( w ) ) / w );
 466         y1 = x1 * w;
 467         y2 = x2 * w;
 468
 469         // deflect both left and right edges randomly and independently, so that:
 470         // (1) dc->tremor=1 corresponds to sigma=1, decreasing dc->tremor narrows the bell curve;
 471         // (2) deflection depends on width, but is upped for small widths for better visual uniformity across widths;
 472         // (3) deflection somewhat depends on speed, to prevent fast strokes looking
 473         // comparatively smooth and slow ones excessively jittery
 474         tremble_left  = (y1)*dc->tremor * (0.15 + 0.8*width) * (0.35 + 14*Geom::L2(dc->vel));
 475         tremble_right = (y2)*dc->tremor * (0.15 + 0.8*width) * (0.35 + 14*Geom::L2(dc->vel));
 476     }
 477
 478     if ( width < 0.02 * dc->width ) {
 479         width = 0.02 * dc->width;
 480     }
 481
 482     double dezoomify_factor = 0.05 * 1000;
 483     if (!dc->abs_width) {
 484         dezoomify_factor /= SP_EVENT_CONTEXT(dc)->desktop->current_zoom();
 485     }
 486
 487     Geom::Point del_left = dezoomify_factor * (width + tremble_left) * dc->ang;
 488     Geom::Point del_right = dezoomify_factor * (width + tremble_right) * dc->ang;
 489
 490     dc->point1[dc->npoints] = brush + del_left;
 491     dc->point2[dc->npoints] = brush - del_right;
 492
 493     dc->del = 0.5*(del_left + del_right);
 494
 495     dc->npoints++;
 496 }
 497
 498 void
 499 sp_ddc_update_toolbox (SPDesktop *desktop, const gchar *id, double value)
 500 {
 501     desktop->setToolboxAdjustmentValue (id, value);
 502 }
 503
 504 static void
 505 calligraphic_cancel(SPDynaDrawContext *dc)
 506 {
 507     SPDesktop *desktop = SP_EVENT_CONTEXT(dc)->desktop;
 508     dc->dragging = FALSE;
 509     dc->is_drawing = false;
 510     sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate), 0);
 511             /* Remove all temporary line segments */
 512             while (dc->segments) {
 513                 gtk_object_destroy(GTK_OBJECT(dc->segments->data));
 514                 dc->segments = g_slist_remove(dc->segments, dc->segments->data);
 515             }
 516             /* reset accumulated curve */
 517             dc->accumulated->reset();
 518             clear_current(dc);
 519             if (dc->repr) {
 520                 dc->repr = NULL;
 521             }
 522 }
 523
 524
 525 gint
 526 sp_dyna_draw_context_root_handler(SPEventContext *event_context,
 527                                   GdkEvent *event)
 528 {
 529     SPDynaDrawContext *dc = SP_DYNA_DRAW_CONTEXT(event_context);
 530     SPDesktop *desktop = event_context->desktop;
 531
 532     gint ret = FALSE;
 533
 534     switch (event->type) {
 535         case GDK_BUTTON_PRESS:
 536             if (event->button.button == 1 && !event_context->space_panning) {
 537
 538                 SPDesktop *desktop = SP_EVENT_CONTEXT_DESKTOP(dc);
 539
 540                 if (Inkscape::have_viable_layer(desktop, dc->_message_context) == false) {
 541                     return TRUE;
 542                 }
 543
 544                 Geom::Point const button_w(event->button.x,
 545                                          event->button.y);
 546                 Geom::Point const button_dt(desktop->w2d(button_w));
 547                 sp_dyna_draw_reset(dc, button_dt);
 548                 sp_dyna_draw_extinput(dc, event);
 549                 sp_dyna_draw_apply(dc, button_dt);
 550                 dc->accumulated->reset();
 551                 if (dc->repr) {
 552                     dc->repr = NULL;
 553                 }
 554
 555                 /* initialize first point */
 556                 dc->npoints = 0;
 557
 558                 sp_canvas_item_grab(SP_CANVAS_ITEM(desktop->acetate),
 559                                     ( GDK_KEY_PRESS_MASK |
 560                                       GDK_BUTTON_RELEASE_MASK |
 561                                       GDK_POINTER_MOTION_MASK |
 562                                       GDK_BUTTON_PRESS_MASK ),
 563                                     NULL,
 564                                     event->button.time);
 565
 566                 ret = TRUE;
 567
 568                 sp_canvas_force_full_redraw_after_interruptions(desktop->canvas, 3);
 569                 dc->is_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 = sp_item_dt2i_affine(selected) * sp_item_i2doc_affine(selected);
 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 SPEED_ELEMENTS 12
 629 #define SPEED_MIN 0.12
 630 #define SPEED_NORMAL 0.65
 631
 632                     // speed is the movement of the nearest point along the guide path, divided by
 633                     // the movement of the pointer at the same period; it is averaged for the last
 634                     // SPEED_ELEMENTS motion events.  Normally, as you track the guide path, speed
 635                     // is about 1, i.e. the nearest point on the path is moved by about the same
 636                     // distance as the pointer. If the speed starts to decrease, we are losing
 637                     // contact with the guide; if it drops below SPEED_MIN, we are on our own and
 638                     // not attracted to guide anymore. Most often this happens when you have
 639                     // tracked to the end of a guide calligraphic stroke and keep moving
 640                     // further. We try to handle this situation gracefully: not stick with the
 641                     // guide forever but let go of it smoothly and without sharp jerks (non-zero
 642                     // mass recommended; with zero mass, jerks are still quite noticeable).
 643
 644                     double speed = 1;
 645                     if (Geom::L2(dc->hatch_last_nearest) != 0) {
 646                         // the distance nearest moved since the last motion event
 647                         double nearest_moved = Geom::L2(nearest - dc->hatch_last_nearest);
 648                         // the distance pointer moved since the last motion event
 649                         double pointer_moved = Geom::L2(pointer - dc->hatch_last_pointer);
 650                         // store them in stacks limited to SPEED_ELEMENTS
 651                         dc->hatch_nearest_past.push_front(nearest_moved);
 652                         if (dc->hatch_nearest_past.size() > SPEED_ELEMENTS)
 653                             dc->hatch_nearest_past.pop_back();
 654                         dc->hatch_pointer_past.push_front(pointer_moved);
 655                         if (dc->hatch_pointer_past.size() > SPEED_ELEMENTS)
 656                             dc->hatch_pointer_past.pop_back();
 657
 658                         // If the stacks are full,
 659                         if (dc->hatch_nearest_past.size() == SPEED_ELEMENTS) {
 660                             // calculate the sums of all stored movements
 661                             double nearest_sum = std::accumulate (dc->hatch_nearest_past.begin(), dc->hatch_nearest_past.end(), 0.0);
 662                             double pointer_sum = std::accumulate (dc->hatch_pointer_past.begin(), dc->hatch_pointer_past.end(), 0.0);
 663                             // and divide to get the speed
 664                             speed = nearest_sum/pointer_sum;
 665                             //g_print ("nearest sum %g  pointer_sum %g  speed %g\n", nearest_sum, pointer_sum, speed);
 666                         }
 667                     }
 668
 669                     if (   dc->hatch_escaped  // already escaped, do not reattach
 670                         || (speed < SPEED_MIN) // stuck; most likely reached end of traced stroke
 671                         || (dc->hatch_spacing > 0 && hatch_dist > 50 * dc->hatch_spacing) // went too far from the guide
 672                         ) {
 673                         // We are NOT attracted to the guide!
 674
 675                         //g_print ("\nlast_nearest %g %g   nearest %g %g  pointer %g %g  pos %d %g\n", dc->last_nearest[NR::X], dc->last_nearest[NR::Y], nearest[NR::X], nearest[NR::Y], pointer[NR::X], pointer[NR::Y], position->piece, position->t);
 676
 677                         // Remember hatch_escaped so we don't get
 678                         // attracted again until the end of this stroke
 679                         dc->hatch_escaped = true;
 680
 681                     } else {
 682
 683                         // Calculate angle cosine of this vector-to-guide and all past vectors
 684                         // summed, to detect if we accidentally flipped to the other side of the
 685                         // guide
 686                         double dot = Geom::dot (pointer - nearest, dc->hatch_vector_accumulated);
 687                         dot /= Geom::L2(pointer - nearest) * Geom::L2(dc->hatch_vector_accumulated);
 688
 689                         if (dc->hatch_spacing != 0) { // spacing was already set
 690                             double target;
 691                             if (speed > SPEED_NORMAL) {
 692                                 // all ok, strictly obey the spacing
 693                                 target = dc->hatch_spacing;
 694                             } else {
 695                                 // looks like we're starting to lose speed,
 696                                 // so _gradually_ let go attraction to prevent jerks
 697                                 target = (dc->hatch_spacing * speed + hatch_dist * (SPEED_NORMAL - speed))/SPEED_NORMAL;
 698                             }
 699                             if (!IS_NAN(dot) && dot < -0.5) {// flip
 700                                 target = -target;
 701                             }
 702
 703                             // This is the track pointer that we will use instead of the real one
 704                             Geom::Point new_pointer = nearest + target * hatch_unit_vector;
 705
 706                             // some limited feedback: allow persistent pulling to slightly change
 707                             // the spacing
 708                             dc->hatch_spacing += (hatch_dist - dc->hatch_spacing)/3500;
 709
 710                             // return it to the desktop coords
 711                             motion_dt = new_pointer * motion_to_curve.inverse();
 712
 713                         } else {
 714                             // this is the first motion event, set the dist
 715                             dc->hatch_spacing = hatch_dist;
 716                         }
 717
 718                         // remember last points
 719                         dc->hatch_last_pointer = pointer;
 720                         dc->hatch_last_nearest = nearest;
 721                         dc->hatch_vector_accumulated += (pointer - nearest);
 722                     }
 723
 724                     dc->_message_context->set(Inkscape::NORMAL_MESSAGE, dc->hatch_escaped? _("Tracking: <b>connection to guide path lost!</b>") : _("<b>Tracking</b> a guide path"));
 725
 726                 } else {
 727                     dc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("<b>Drawing</b> a calligraphic stroke"));
 728                 }
 729
 730                 if (!sp_dyna_draw_apply(dc, motion_dt)) {
 731                     ret = TRUE;
 732                     break;
 733                 }
 734
 735                 if ( dc->cur != dc->last ) {
 736                     sp_dyna_draw_brush(dc);
 737                     g_assert( dc->npoints > 0 );
 738                     fit_and_split(dc, FALSE);
 739                 }
 740                 ret = TRUE;
 741             }
 742
 743             // Draw the hatching circle if necessary
 744             if (event->motion.state & GDK_CONTROL_MASK) {
 745                 if (dc->hatch_spacing == 0 && hatch_dist != 0) {
 746                     // Haven't set spacing yet: gray, center free, update radius live
 747                     Geom::Point c = desktop->w2d(motion_w);
 748                     Geom::Matrix const sm (Geom::Scale(hatch_dist, hatch_dist) * Geom::Translate(c));
 749                     sp_canvas_item_affine_absolute(dc->hatch_area, sm);
 750                     sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(dc->hatch_area), 0x7f7f7fff, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 751                     sp_canvas_item_show(dc->hatch_area);
 752                 } else if (dc->dragging && !dc->hatch_escaped) {
 753                     // Tracking: green, center snapped, fixed radius
 754                     Geom::Point c = motion_dt;
 755                     Geom::Matrix const sm (Geom::Scale(dc->hatch_spacing, dc->hatch_spacing) * Geom::Translate(c));
 756                     sp_canvas_item_affine_absolute(dc->hatch_area, sm);
 757                     sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(dc->hatch_area), 0x00FF00ff, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 758                     sp_canvas_item_show(dc->hatch_area);
 759                 } else if (dc->dragging && dc->hatch_escaped) {
 760                     // Tracking escaped: red, center free, fixed radius
 761                     Geom::Point c = desktop->w2d(motion_w);
 762                     Geom::Matrix const sm (Geom::Scale(dc->hatch_spacing, dc->hatch_spacing) * Geom::Translate(c));
 763
 764                     sp_canvas_item_affine_absolute(dc->hatch_area, sm);
 765                     sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(dc->hatch_area), 0xFF0000ff, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 766                     sp_canvas_item_show(dc->hatch_area);
 767                 } else {
 768                     // Not drawing but spacing set: gray, center snapped, fixed radius
 769                     Geom::Point c = (nearest + dc->hatch_spacing * hatch_unit_vector) * motion_to_curve.inverse();
 770                     if (!IS_NAN(c[Geom::X]) && !IS_NAN(c[Geom::Y])) {
 771                         Geom::Matrix const sm (Geom::Scale(dc->hatch_spacing, dc->hatch_spacing) * Geom::Translate(c));
 772                         sp_canvas_item_affine_absolute(dc->hatch_area, sm);
 773                         sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(dc->hatch_area), 0x7f7f7fff, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 774                         sp_canvas_item_show(dc->hatch_area);
 775                     }
 776                 }
 777             } else {
 778                 sp_canvas_item_hide(dc->hatch_area);
 779             }
 780         }
 781         break;
 782
 783
 784     case GDK_BUTTON_RELEASE:
 785     {
 786         Geom::Point const motion_w(event->button.x, event->button.y);
 787         Geom::Point const motion_dt(desktop->w2d(motion_w));
 788
 789         sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate), event->button.time);
 790         sp_canvas_end_forced_full_redraws(desktop->canvas);
 791         dc->is_drawing = false;
 792
 793         if (dc->dragging && event->button.button == 1 && !event_context->space_panning) {
 794             dc->dragging = FALSE;
 795
 796             sp_dyna_draw_apply(dc, motion_dt);
 797
 798             /* Remove all temporary line segments */
 799             while (dc->segments) {
 800                 gtk_object_destroy(GTK_OBJECT(dc->segments->data));
 801                 dc->segments = g_slist_remove(dc->segments, dc->segments->data);
 802             }
 803
 804             /* Create object */
 805             fit_and_split(dc, TRUE);
 806             if (accumulate_calligraphic(dc))
 807                 set_to_accumulated(dc, event->button.state & GDK_SHIFT_MASK); // performs document_done
 808             else
 809                 g_warning ("Failed to create path: invalid data in dc->cal1 or dc->cal2");
 810
 811             /* reset accumulated curve */
 812             dc->accumulated->reset();
 813
 814             clear_current(dc);
 815             if (dc->repr) {
 816                 dc->repr = NULL;
 817             }
 818
 819             if (!dc->hatch_pointer_past.empty()) dc->hatch_pointer_past.clear();
 820             if (!dc->hatch_nearest_past.empty()) dc->hatch_nearest_past.clear();
 821             dc->hatch_last_nearest = Geom::Point(0,0);
 822             dc->hatch_last_pointer = Geom::Point(0,0);
 823             dc->hatch_vector_accumulated = Geom::Point(0,0);
 824             dc->hatch_escaped = false;
 825             dc->hatch_item = NULL;
 826             dc->hatch_livarot_path = NULL;
 827
 828             if (dc->hatch_spacing != 0 && !dc->keep_selected) {
 829                 // we do not select the newly drawn path, so increase spacing by step
 830                 if (dc->hatch_spacing_step == 0) {
 831                     dc->hatch_spacing_step = dc->hatch_spacing;
 832                 }
 833                 dc->hatch_spacing += dc->hatch_spacing_step;
 834             }
 835
 836             dc->_message_context->clear();
 837             ret = TRUE;
 838         }
 839         break;
 840     }
 841
 842     case GDK_KEY_PRESS:
 843         switch (get_group0_keyval (&event->key)) {
 844         case GDK_Up:
 845         case GDK_KP_Up:
 846             if (!MOD__CTRL_ONLY) {
 847                 dc->angle += 5.0;
 848                 if (dc->angle > 90.0)
 849                     dc->angle = 90.0;
 850                 sp_ddc_update_toolbox (desktop, "calligraphy-angle", dc->angle);
 851                 ret = TRUE;
 852             }
 853             break;
 854         case GDK_Down:
 855         case GDK_KP_Down:
 856             if (!MOD__CTRL_ONLY) {
 857                 dc->angle -= 5.0;
 858                 if (dc->angle < -90.0)
 859                     dc->angle = -90.0;
 860                 sp_ddc_update_toolbox (desktop, "calligraphy-angle", dc->angle);
 861                 ret = TRUE;
 862             }
 863             break;
 864         case GDK_Right:
 865         case GDK_KP_Right:
 866             if (!MOD__CTRL_ONLY) {
 867                 dc->width += 0.01;
 868                 if (dc->width > 1.0)
 869                     dc->width = 1.0;
 870                 sp_ddc_update_toolbox (desktop, "altx-calligraphy", dc->width * 100); // the same spinbutton is for alt+x
 871                 ret = TRUE;
 872             }
 873             break;
 874         case GDK_Left:
 875         case GDK_KP_Left:
 876             if (!MOD__CTRL_ONLY) {
 877                 dc->width -= 0.01;
 878                 if (dc->width < 0.01)
 879                     dc->width = 0.01;
 880                 sp_ddc_update_toolbox (desktop, "altx-calligraphy", dc->width * 100);
 881                 ret = TRUE;
 882             }
 883             break;
 884         case GDK_Home:
 885         case GDK_KP_Home:
 886             dc->width = 0.01;
 887             sp_ddc_update_toolbox (desktop, "altx-calligraphy", dc->width * 100);
 888             ret = TRUE;
 889             break;
 890         case GDK_End:
 891         case GDK_KP_End:
 892             dc->width = 1.0;
 893             sp_ddc_update_toolbox (desktop, "altx-calligraphy", dc->width * 100);
 894             ret = TRUE;
 895             break;
 896         case GDK_x:
 897         case GDK_X:
 898             if (MOD__ALT_ONLY) {
 899                 desktop->setToolboxFocusTo ("altx-calligraphy");
 900                 ret = TRUE;
 901             }
 902             break;
 903         case GDK_Escape:
 904             if (dc->is_drawing) {
 905                 // if drawing, cancel, otherwise pass it up for deselecting
 906                 calligraphic_cancel (dc);
 907                 ret = TRUE;
 908             }
 909             break;
 910         case GDK_z:
 911         case GDK_Z:
 912             if (MOD__CTRL_ONLY && dc->is_drawing) {
 913                 // if drawing, cancel, otherwise pass it up for undo
 914                 calligraphic_cancel (dc);
 915                 ret = TRUE;
 916             }
 917             break;
 918         default:
 919             break;
 920         }
 921         break;
 922
 923     case GDK_KEY_RELEASE:
 924         switch (get_group0_keyval(&event->key)) {
 925             case GDK_Control_L:
 926             case GDK_Control_R:
 927                 dc->_message_context->clear();
 928                 dc->hatch_spacing = 0;
 929                 dc->hatch_spacing_step = 0;
 930                 break;
 931             default:
 932                 break;
 933         }
 934
 935     default:
 936         break;
 937     }
 938
 939     if (!ret) {
 940         if (((SPEventContextClass *) dd_parent_class)->root_handler) {
 941             ret = ((SPEventContextClass *) dd_parent_class)->root_handler(event_context, event);
 942         }
 943     }
 944
 945     return ret;
 946 }
 947
 948
 949 static void
 950 clear_current(SPDynaDrawContext *dc)
 951 {
 952     /* reset bpath */
 953     sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(dc->currentshape), NULL);
 954     /* reset curve */
 955     dc->currentcurve->reset();
 956     dc->cal1->reset();
 957     dc->cal2->reset();
 958     /* reset points */
 959     dc->npoints = 0;
 960 }
 961
 962 static void
 963 set_to_accumulated(SPDynaDrawContext *dc, bool unionize)
 964 {
 965     SPDesktop *desktop = SP_EVENT_CONTEXT(dc)->desktop;
 966
 967     if (!dc->accumulated->is_empty()) {
 968         if (!dc->repr) {
 969             /* Create object */
 970             Inkscape::XML::Document *xml_doc = sp_document_repr_doc(desktop->doc());
 971             Inkscape::XML::Node *repr = xml_doc->createElement("svg:path");
 972
 973             /* Set style */
 974             sp_desktop_apply_style_tool (desktop, repr, "/tools/calligraphic", false);
 975
 976             dc->repr = repr;
 977
 978             SPItem *item=SP_ITEM(desktop->currentLayer()->appendChildRepr(dc->repr));
 979             Inkscape::GC::release(dc->repr);
 980             item->transform = sp_item_i2doc_affine(SP_ITEM(desktop->currentLayer())).inverse();
 981             item->updateRepr();
 982         }
 983         Geom::PathVector pathv = dc->accumulated->get_pathvector() * sp_desktop_dt2doc_affine(desktop);
 984         gchar *str = sp_svg_write_path(pathv);
 985         g_assert( str != NULL );
 986         dc->repr->setAttribute("d", str);
 987         g_free(str);
 988
 989         if (unionize) {
 990             sp_desktop_selection(desktop)->add(dc->repr);
 991             sp_selected_path_union_skip_undo(desktop);
 992         } else {
 993             if (dc->keep_selected) {
 994                 sp_desktop_selection(desktop)->set(dc->repr);
 995             }
 996         }
 997
 998     } else {
 999         if (dc->repr) {
1000             sp_repr_unparent(dc->repr);
1001         }
1002         dc->repr = NULL;
1003     }
1004
1005     sp_document_done(sp_desktop_document(desktop), SP_VERB_CONTEXT_CALLIGRAPHIC,
1006                      _("Draw calligraphic stroke"));
1007 }
1008
1009 static void
1010 add_cap(SPCurve *curve,
1011         Geom::Point const &from,
1012         Geom::Point const &to,
1013         double rounding)
1014 {
1015     if (Geom::L2( to - from ) > DYNA_EPSILON) {
1016         Geom::Point vel = rounding * Geom::rot90( to - from ) / sqrt(2.0);
1017         double mag = Geom::L2(vel);
1018
1019         Geom::Point v = mag * Geom::rot90( to - from ) / Geom::L2( to - from );
1020         curve->curveto(from + v, to + v, to);
1021     }
1022 }
1023
1024 static bool
1025 accumulate_calligraphic(SPDynaDrawContext *dc)
1026 {
1027         if (
1028             dc->cal1->is_empty() ||
1029             dc->cal2->is_empty() ||
1030             (dc->cal1->get_segment_count() <= 0) ||
1031             dc->cal1->first_path()->closed()
1032             ) {
1033             dc->cal1->reset();
1034             dc->cal2->reset();
1035             return false; // failure
1036         }
1037
1038         SPCurve *rev_cal2 = dc->cal2->create_reverse();
1039         if (
1040             (rev_cal2->get_segment_count() <= 0) ||
1041             rev_cal2->first_path()->closed()
1042             ) {
1043             rev_cal2->unref();
1044             dc->cal1->reset();
1045             dc->cal2->reset();
1046             return false; // failure
1047         }
1048
1049         Geom::CubicBezier const * dc_cal1_firstseg  = dynamic_cast<Geom::CubicBezier const *>( dc->cal1->first_segment() );
1050         Geom::CubicBezier const * rev_cal2_firstseg = dynamic_cast<Geom::CubicBezier const *>( rev_cal2->first_segment() );
1051         Geom::CubicBezier const * dc_cal1_lastseg   = dynamic_cast<Geom::CubicBezier const *>( dc->cal1->last_segment() );
1052         Geom::CubicBezier const * rev_cal2_lastseg  = dynamic_cast<Geom::CubicBezier const *>( rev_cal2->last_segment() );
1053
1054         if (
1055             !dc_cal1_firstseg ||
1056             !rev_cal2_firstseg ||
1057             !dc_cal1_lastseg ||
1058             !rev_cal2_lastseg
1059             ) {
1060             rev_cal2->unref();
1061             dc->cal1->reset();
1062             dc->cal2->reset();
1063             return false; // failure
1064         }
1065
1066         dc->accumulated->reset(); /*  Is this required ?? */
1067
1068         dc->accumulated->append(dc->cal1, false);
1069
1070         add_cap(dc->accumulated, (*dc_cal1_lastseg)[3], (*rev_cal2_firstseg)[0], dc->cap_rounding);
1071
1072         dc->accumulated->append(rev_cal2, true);
1073
1074         add_cap(dc->accumulated, (*rev_cal2_lastseg)[3], (*dc_cal1_firstseg)[0], dc->cap_rounding);
1075
1076         dc->accumulated->closepath();
1077
1078         rev_cal2->unref();
1079
1080         dc->cal1->reset();
1081         dc->cal2->reset();
1082
1083         return true; // success
1084 }
1085
1086 static double square(double const x)
1087 {
1088     return x * x;
1089 }
1090
1091 static void
1092 fit_and_split(SPDynaDrawContext *dc, gboolean release)
1093 {
1094     SPDesktop *desktop = SP_EVENT_CONTEXT(dc)->desktop;
1095
1096     double const tolerance_sq = square( desktop->w2d().descrim() * TOLERANCE_CALLIGRAPHIC );
1097
1098 #ifdef DYNA_DRAW_VERBOSE
1099     g_print("[F&S:R=%c]", release?'T':'F');
1100 #endif
1101
1102     if (!( dc->npoints > 0 && dc->npoints < SAMPLING_SIZE ))
1103         return; // just clicked
1104
1105     if ( dc->npoints == SAMPLING_SIZE - 1 || release ) {
1106 #define BEZIER_SIZE       4
1107 #define BEZIER_MAX_BEZIERS  8
1108 #define BEZIER_MAX_LENGTH ( BEZIER_SIZE * BEZIER_MAX_BEZIERS )
1109
1110 #ifdef DYNA_DRAW_VERBOSE
1111         g_print("[F&S:#] dc->npoints:%d, release:%s\n",
1112                 dc->npoints, release ? "TRUE" : "FALSE");
1113 #endif
1114
1115         /* Current calligraphic */
1116         if ( dc->cal1->is_empty() || dc->cal2->is_empty() ) {
1117             /* dc->npoints > 0 */
1118             /* g_print("calligraphics(1|2) reset\n"); */
1119             dc->cal1->reset();
1120             dc->cal2->reset();
1121
1122             dc->cal1->moveto(dc->point1[0]);
1123             dc->cal2->moveto(dc->point2[0]);
1124         }
1125
1126         Geom::Point b1[BEZIER_MAX_LENGTH];
1127         gint const nb1 = Geom::bezier_fit_cubic_r(b1, dc->point1, dc->npoints,
1128                                                tolerance_sq, BEZIER_MAX_BEZIERS);
1129         g_assert( nb1 * BEZIER_SIZE <= gint(G_N_ELEMENTS(b1)) );
1130
1131         Geom::Point b2[BEZIER_MAX_LENGTH];
1132         gint const nb2 = Geom::bezier_fit_cubic_r(b2, dc->point2, dc->npoints,
1133                                                tolerance_sq, BEZIER_MAX_BEZIERS);
1134         g_assert( nb2 * BEZIER_SIZE <= gint(G_N_ELEMENTS(b2)) );
1135
1136         if ( nb1 != -1 && nb2 != -1 ) {
1137             /* Fit and draw and reset state */
1138 #ifdef DYNA_DRAW_VERBOSE
1139             g_print("nb1:%d nb2:%d\n", nb1, nb2);
1140 #endif
1141             /* CanvasShape */
1142             if (! release) {
1143                 dc->currentcurve->reset();
1144                 dc->currentcurve->moveto(b1[0]);
1145                 for (Geom::Point *bp1 = b1; bp1 < b1 + BEZIER_SIZE * nb1; bp1 += BEZIER_SIZE) {
1146                     dc->currentcurve->curveto(bp1[1], bp1[2], bp1[3]);
1147                 }
1148                 dc->currentcurve->lineto(b2[BEZIER_SIZE*(nb2-1) + 3]);
1149                 for (Geom::Point *bp2 = b2 + BEZIER_SIZE * ( nb2 - 1 ); bp2 >= b2; bp2 -= BEZIER_SIZE) {
1150                     dc->currentcurve->curveto(bp2[2], bp2[1], bp2[0]);
1151                 }
1152                 // FIXME: dc->segments is always NULL at this point??
1153                 if (!dc->segments) { // first segment
1154                     add_cap(dc->currentcurve, b2[0], b1[0], dc->cap_rounding);
1155                 }
1156                 dc->currentcurve->closepath();
1157                 sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(dc->currentshape), dc->currentcurve);
1158             }
1159
1160             /* Current calligraphic */
1161             for (Geom::Point *bp1 = b1; bp1 < b1 + BEZIER_SIZE * nb1; bp1 += BEZIER_SIZE) {
1162                 dc->cal1->curveto(bp1[1], bp1[2], bp1[3]);
1163             }
1164             for (Geom::Point *bp2 = b2; bp2 < b2 + BEZIER_SIZE * nb2; bp2 += BEZIER_SIZE) {
1165                 dc->cal2->curveto(bp2[1], bp2[2], bp2[3]);
1166             }
1167         } else {
1168             /* fixme: ??? */
1169 #ifdef DYNA_DRAW_VERBOSE
1170             g_print("[fit_and_split] failed to fit-cubic.\n");
1171 #endif
1172             draw_temporary_box(dc);
1173
1174             for (gint i = 1; i < dc->npoints; i++) {
1175                 dc->cal1->lineto(dc->point1[i]);
1176             }
1177             for (gint i = 1; i < dc->npoints; i++) {
1178                 dc->cal2->lineto(dc->point2[i]);
1179             }
1180         }
1181
1182         /* Fit and draw and copy last point */
1183 #ifdef DYNA_DRAW_VERBOSE
1184         g_print("[%d]Yup\n", dc->npoints);
1185 #endif
1186         if (!release) {
1187             g_assert(!dc->currentcurve->is_empty());
1188
1189             SPCanvasItem *cbp = sp_canvas_item_new(sp_desktop_sketch(desktop),
1190                                                    SP_TYPE_CANVAS_BPATH,
1191                                                    NULL);
1192             SPCurve *curve = dc->currentcurve->copy();
1193             sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH (cbp), curve);
1194             curve->unref();
1195
1196             guint32 fillColor = sp_desktop_get_color_tool (desktop, "/tools/calligraphic", true);
1197             //guint32 strokeColor = sp_desktop_get_color_tool (desktop, "/tools/calligraphic", false);
1198             double opacity = sp_desktop_get_master_opacity_tool (desktop, "/tools/calligraphic");
1199             double fillOpacity = sp_desktop_get_opacity_tool (desktop, "/tools/calligraphic", true);
1200             //double strokeOpacity = sp_desktop_get_opacity_tool (desktop, "/tools/calligraphic", false);
1201             sp_canvas_bpath_set_fill(SP_CANVAS_BPATH(cbp), ((fillColor & 0xffffff00) | SP_COLOR_F_TO_U(opacity*fillOpacity)), SP_WIND_RULE_EVENODD);
1202             //on second thougtht don't do stroke yet because we don't have stoke-width yet and because stoke appears between segments while drawing
1203             //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);
1204             sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(cbp), 0x00000000, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
1205             /* fixme: Cannot we cascade it to root more clearly? */
1206             g_signal_connect(G_OBJECT(cbp), "event", G_CALLBACK(sp_desktop_root_handler), desktop);
1207
1208             dc->segments = g_slist_prepend(dc->segments, cbp);
1209         }
1210
1211         dc->point1[0] = dc->point1[dc->npoints - 1];
1212         dc->point2[0] = dc->point2[dc->npoints - 1];
1213         dc->npoints = 1;
1214     } else {
1215         draw_temporary_box(dc);
1216     }
1217 }
1218
1219 static void
1220 draw_temporary_box(SPDynaDrawContext *dc)
1221 {
1222     dc->currentcurve->reset();
1223
1224     dc->currentcurve->moveto(dc->point2[dc->npoints-1]);
1225     for (gint i = dc->npoints-2; i >= 0; i--) {
1226         dc->currentcurve->lineto(dc->point2[i]);
1227     }
1228     for (gint i = 0; i < dc->npoints; i++) {
1229         dc->currentcurve->lineto(dc->point1[i]);
1230     }
1231
1232     if (dc->npoints >= 2) {
1233         add_cap(dc->currentcurve, dc->point1[dc->npoints-1], dc->point2[dc->npoints-1], dc->cap_rounding);
1234     }
1235
1236     dc->currentcurve->closepath();
1237     sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(dc->currentshape), dc->currentcurve);
1238 }
1239
1240 /*
1241   Local Variables:
1242   mode:c++
1243   c-file-style:"stroustrup"
1244   c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
1245   indent-tabs-mode:nil
1246   fill-column:99
1247   End:
1248 */
1249 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :