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 "display/bezier-utils.h"
  38 #include "display/curve.h"
  39 #include <glib/gmem.h>
  40 #include "macros.h"
  41 #include "document.h"
  42 #include "selection.h"
  43 #include "desktop.h"
  44 #include "desktop-events.h"
  45 #include "desktop-handles.h"
  46 #include "desktop-affine.h"
  47 #include "desktop-style.h"
  48 #include "message-context.h"
  49 #include "prefs-utils.h"
  50 #include "pixmaps/cursor-calligraphy.xpm"
  51 #include "libnr/nr-matrix-ops.h"
  52 #include "libnr/nr-scale-translate-ops.h"
  53 #include "libnr/nr-convert2geom.h"
  54 #include "xml/repr.h"
  55 #include "context-fns.h"
  56 #include "sp-item.h"
  57 #include "inkscape.h"
  58 #include "color.h"
  59 #include "splivarot.h"
  60 #include "sp-item-group.h"
  61 #include "sp-shape.h"
  62 #include "sp-path.h"
  63 #include "sp-text.h"
  64 #include "display/canvas-bpath.h"
  65 #include "display/canvas-arena.h"
  66 #include "livarot/Shape.h"
  67 #include <2geom/isnan.h>
  68 #include <2geom/pathvector.h>
  69
  70 #include "dyna-draw-context.h"
  71
  72 #define DDC_RED_RGBA 0xff0000ff
  73
  74 #define TOLERANCE_CALLIGRAPHIC 0.1
  75
  76 #define DYNA_EPSILON 0.5e-6
  77 #define DYNA_EPSILON_START 0.5e-2
  78 #define DYNA_VEL_START 1e-5
  79
  80 #define DYNA_MIN_WIDTH 1.0e-6
  81
  82 static void sp_dyna_draw_context_class_init(SPDynaDrawContextClass *klass);
  83 static void sp_dyna_draw_context_init(SPDynaDrawContext *ddc);
  84 static void sp_dyna_draw_context_dispose(GObject *object);
  85
  86 static void sp_dyna_draw_context_setup(SPEventContext *ec);
  87 static void sp_dyna_draw_context_set(SPEventContext *ec, gchar const *key, gchar const *val);
  88 static gint sp_dyna_draw_context_root_handler(SPEventContext *ec, GdkEvent *event);
  89
  90 static void clear_current(SPDynaDrawContext *dc);
  91 static void set_to_accumulated(SPDynaDrawContext *dc, bool unionize);
  92 static void add_cap(SPCurve *curve, Geom::Point const &from, Geom::Point const &to, double rounding);
  93 static bool accumulate_calligraphic(SPDynaDrawContext *dc);
  94
  95 static void fit_and_split(SPDynaDrawContext *ddc, gboolean release);
  96
  97 static void sp_dyna_draw_reset(SPDynaDrawContext *ddc, Geom::Point p);
  98 static Geom::Point sp_dyna_draw_get_npoint(SPDynaDrawContext const *ddc, Geom::Point v);
  99 static Geom::Point sp_dyna_draw_get_vpoint(SPDynaDrawContext const *ddc, Geom::Point n);
 100 static void draw_temporary_box(SPDynaDrawContext *dc);
 101
 102
 103 static SPEventContextClass *dd_parent_class = 0;
 104
 105 GType sp_dyna_draw_context_get_type(void)
 106 {
 107     static GType type = 0;
 108     if (!type) {
 109         GTypeInfo info = {
 110             sizeof(SPDynaDrawContextClass),
 111             0, // base_init
 112             0, // base_finalize
 113             (GClassInitFunc)sp_dyna_draw_context_class_init,
 114             0, // class_finalize
 115             0, // class_data
 116             sizeof(SPDynaDrawContext),
 117             0, // n_preallocs
 118             (GInstanceInitFunc)sp_dyna_draw_context_init,
 119             0 // value_table
 120         };
 121         type = g_type_register_static(SP_TYPE_COMMON_CONTEXT, "SPDynaDrawContext", &info, static_cast<GTypeFlags>(0));
 122     }
 123     return type;
 124 }
 125
 126 static void
 127 sp_dyna_draw_context_class_init(SPDynaDrawContextClass *klass)
 128 {
 129     GObjectClass *object_class = (GObjectClass *) klass;
 130     SPEventContextClass *event_context_class = (SPEventContextClass *) klass;
 131
 132     dd_parent_class = (SPEventContextClass*)g_type_class_peek_parent(klass);
 133
 134     object_class->dispose = sp_dyna_draw_context_dispose;
 135
 136     event_context_class->setup = sp_dyna_draw_context_setup;
 137     event_context_class->set = sp_dyna_draw_context_set;
 138     event_context_class->root_handler = sp_dyna_draw_context_root_handler;
 139 }
 140
 141 static void
 142 sp_dyna_draw_context_init(SPDynaDrawContext *ddc)
 143 {
 144     ddc->cursor_shape = cursor_calligraphy_xpm;
 145     ddc->hot_x = 4;
 146     ddc->hot_y = 4;
 147
 148     ddc->vel_thin = 0.1;
 149     ddc->flatness = 0.9;
 150     ddc->cap_rounding = 0.0;
 151
 152     ddc->abs_width = false;
 153     ddc->keep_selected = true;
 154
 155     ddc->hatch_spacing = 0;
 156     ddc->hatch_spacing_step = 0;
 157     new (&ddc->hatch_pointer_past) std::list<double>();
 158     new (&ddc->hatch_nearest_past) std::list<double>();
 159     ddc->hatch_last_nearest = Geom::Point(0,0);
 160     ddc->hatch_last_pointer = Geom::Point(0,0);
 161     ddc->hatch_vector_accumulated = Geom::Point(0,0);
 162     ddc->hatch_escaped = false;
 163     ddc->hatch_area = NULL;
 164     ddc->hatch_item = NULL;
 165     ddc->hatch_livarot_path = NULL;
 166
 167     ddc->trace_bg = 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 }
 186
 187 static void
 188 sp_dyna_draw_context_setup(SPEventContext *ec)
 189 {
 190     SPDynaDrawContext *ddc = SP_DYNA_DRAW_CONTEXT(ec);
 191
 192     if (((SPEventContextClass *) dd_parent_class)->setup)
 193         ((SPEventContextClass *) dd_parent_class)->setup(ec);
 194
 195     ddc->accumulated = new SPCurve();
 196     ddc->currentcurve = new SPCurve();
 197
 198     ddc->cal1 = new SPCurve();
 199     ddc->cal2 = new SPCurve();
 200
 201     ddc->currentshape = sp_canvas_item_new(sp_desktop_sketch(ec->desktop), SP_TYPE_CANVAS_BPATH, NULL);
 202     sp_canvas_bpath_set_fill(SP_CANVAS_BPATH(ddc->currentshape), DDC_RED_RGBA, SP_WIND_RULE_EVENODD);
 203     sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(ddc->currentshape), 0x00000000, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 204     /* fixme: Cannot we cascade it to root more clearly? */
 205     g_signal_connect(G_OBJECT(ddc->currentshape), "event", G_CALLBACK(sp_desktop_root_handler), ec->desktop);
 206
 207     {
 208         /* TODO: this can be done either with an arcto, and should maybe also be put in a general file (other tools use this as well) */
 209         SPCurve *c = new SPCurve();
 210         const double C1 = 0.552;
 211         c->moveto(-1,0);
 212         c->curveto(-1, C1, -C1, 1, 0, 1 );
 213         c->curveto(C1, 1, 1, C1, 1, 0 );
 214         c->curveto(1, -C1, C1, -1, 0, -1 );
 215         c->curveto(-C1, -1, -1, -C1, -1, 0 );
 216         c->closepath();
 217         ddc->hatch_area = sp_canvas_bpath_new(sp_desktop_controls(ec->desktop), c);
 218         c->unref();
 219         sp_canvas_bpath_set_fill(SP_CANVAS_BPATH(ddc->hatch_area), 0x00000000,(SPWindRule)0);
 220         sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(ddc->hatch_area), 0x0000007f, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 221         sp_canvas_item_hide(ddc->hatch_area);
 222     }
 223
 224     sp_event_context_read(ec, "mass");
 225     sp_event_context_read(ec, "wiggle");
 226     sp_event_context_read(ec, "angle");
 227     sp_event_context_read(ec, "width");
 228     sp_event_context_read(ec, "thinning");
 229     sp_event_context_read(ec, "tremor");
 230     sp_event_context_read(ec, "flatness");
 231     sp_event_context_read(ec, "tracebackground");
 232     sp_event_context_read(ec, "usepressure");
 233     sp_event_context_read(ec, "usetilt");
 234     sp_event_context_read(ec, "abs_width");
 235     sp_event_context_read(ec, "keep_selected");
 236     sp_event_context_read(ec, "cap_rounding");
 237
 238     ddc->is_drawing = false;
 239
 240     ddc->_message_context = new Inkscape::MessageContext((ec->desktop)->messageStack());
 241
 242     if (prefs_get_int_attribute("tools.calligraphic", "selcue", 0) != 0) {
 243         ec->enableSelectionCue();
 244     }
 245 }
 246
 247 static void
 248 sp_dyna_draw_context_set(SPEventContext *ec, gchar const *key, gchar const *val)
 249 {
 250     SPDynaDrawContext *ddc = SP_DYNA_DRAW_CONTEXT(ec);
 251
 252     if (!strcmp(key, "tracebackground")) {
 253         ddc->trace_bg = (val && strcmp(val, "0"));
 254     } else if (!strcmp(key, "keep_selected")) {
 255         ddc->keep_selected = (val && strcmp(val, "0"));
 256     } else {
 257         //pass on up to parent class to handle common attributes.
 258         if ( dd_parent_class->set ) {
 259             dd_parent_class->set(ec, key, val);
 260         }
 261     }
 262
 263     //g_print("DDC: %g %g %g %g\n", ddc->mass, ddc->drag, ddc->angle, ddc->width);
 264 }
 265
 266 static double
 267 flerp(double f0, double f1, double p)
 268 {
 269     return f0 + ( f1 - f0 ) * p;
 270 }
 271
 272 /* Get normalized point */
 273 static Geom::Point
 274 sp_dyna_draw_get_npoint(SPDynaDrawContext const *dc, Geom::Point v)
 275 {
 276     NR::Rect drect = SP_EVENT_CONTEXT(dc)->desktop->get_display_area();
 277     double const max = MAX ( drect.dimensions()[NR::X], drect.dimensions()[NR::Y] );
 278     return Geom::Point(( v[NR::X] - drect.min()[NR::X] ) / max,  ( v[NR::Y] - drect.min()[NR::Y] ) / max);
 279 }
 280
 281 /* Get view point */
 282 static Geom::Point
 283 sp_dyna_draw_get_vpoint(SPDynaDrawContext const *dc, Geom::Point n)
 284 {
 285     NR::Rect drect = SP_EVENT_CONTEXT(dc)->desktop->get_display_area();
 286     double const max = MAX ( drect.dimensions()[NR::X], drect.dimensions()[NR::Y] );
 287     return Geom::Point(n[NR::X] * max + drect.min()[NR::X], n[NR::Y] * max + drect.min()[NR::Y]);
 288 }
 289
 290 static void
 291 sp_dyna_draw_reset(SPDynaDrawContext *dc, Geom::Point p)
 292 {
 293     dc->last = dc->cur = sp_dyna_draw_get_npoint(dc, p);
 294     dc->vel = Geom::Point(0,0);
 295     dc->vel_max = 0;
 296     dc->acc = Geom::Point(0,0);
 297     dc->ang = Geom::Point(0,0);
 298     dc->del = Geom::Point(0,0);
 299 }
 300
 301 static void
 302 sp_dyna_draw_extinput(SPDynaDrawContext *dc, GdkEvent *event)
 303 {
 304     if (gdk_event_get_axis (event, GDK_AXIS_PRESSURE, &dc->pressure))
 305         dc->pressure = CLAMP (dc->pressure, DDC_MIN_PRESSURE, DDC_MAX_PRESSURE);
 306     else
 307         dc->pressure = DDC_DEFAULT_PRESSURE;
 308
 309     if (gdk_event_get_axis (event, GDK_AXIS_XTILT, &dc->xtilt))
 310         dc->xtilt = CLAMP (dc->xtilt, DDC_MIN_TILT, DDC_MAX_TILT);
 311     else
 312         dc->xtilt = DDC_DEFAULT_TILT;
 313
 314     if (gdk_event_get_axis (event, GDK_AXIS_YTILT, &dc->ytilt))
 315         dc->ytilt = CLAMP (dc->ytilt, DDC_MIN_TILT, DDC_MAX_TILT);
 316     else
 317         dc->ytilt = DDC_DEFAULT_TILT;
 318 }
 319
 320
 321 static gboolean
 322 sp_dyna_draw_apply(SPDynaDrawContext *dc, Geom::Point p)
 323 {
 324     Geom::Point n = sp_dyna_draw_get_npoint(dc, p);
 325
 326     /* Calculate mass and drag */
 327     double const mass = flerp(1.0, 160.0, dc->mass);
 328     double const drag = flerp(0.0, 0.5, dc->drag * dc->drag);
 329
 330     /* Calculate force and acceleration */
 331     Geom::Point force = n - dc->cur;
 332
 333     // If force is below the absolute threshold DYNA_EPSILON,
 334     // or we haven't yet reached DYNA_VEL_START (i.e. at the beginning of stroke)
 335     // _and_ the force is below the (higher) DYNA_EPSILON_START threshold,
 336     // discard this move.
 337     // This prevents flips, blobs, and jerks caused by microscopic tremor of the tablet pen,
 338     // especially bothersome at the start of the stroke where we don't yet have the inertia to
 339     // smooth them out.
 340     if ( NR::L2(force) < DYNA_EPSILON || (dc->vel_max < DYNA_VEL_START && NR::L2(force) < DYNA_EPSILON_START)) {
 341         return FALSE;
 342     }
 343
 344     dc->acc = force / mass;
 345
 346     /* Calculate new velocity */
 347     dc->vel += dc->acc;
 348
 349     if (NR::L2(dc->vel) > dc->vel_max)
 350         dc->vel_max = NR::L2(dc->vel);
 351
 352     /* Calculate angle of drawing tool */
 353
 354     double a1;
 355     if (dc->usetilt) {
 356         // 1a. calculate nib angle from input device tilt:
 357         gdouble length = std::sqrt(dc->xtilt*dc->xtilt + dc->ytilt*dc->ytilt);;
 358
 359         if (length > 0) {
 360             Geom::Point ang1 = Geom::Point(dc->ytilt/length, dc->xtilt/length);
 361             a1 = atan2(ang1);
 362         }
 363         else
 364             a1 = 0.0;
 365     }
 366     else {
 367         // 1b. fixed dc->angle (absolutely flat nib):
 368         double const radians = ( (dc->angle - 90) / 180.0 ) * M_PI;
 369         Geom::Point ang1 = Geom::Point(-sin(radians),  cos(radians));
 370         a1 = atan2(ang1);
 371     }
 372
 373     // 2. perpendicular to dc->vel (absolutely non-flat nib):
 374     gdouble const mag_vel = NR::L2(dc->vel);
 375     if ( mag_vel < DYNA_EPSILON ) {
 376         return FALSE;
 377     }
 378     Geom::Point ang2 = NR::rot90(dc->vel) / mag_vel;
 379
 380     // 3. Average them using flatness parameter:
 381     // calculate angles
 382     double a2 = atan2(ang2);
 383     // flip a2 to force it to be in the same half-circle as a1
 384     bool flipped = false;
 385     if (fabs (a2-a1) > 0.5*M_PI) {
 386         a2 += M_PI;
 387         flipped = true;
 388     }
 389     // normalize a2
 390     if (a2 > M_PI)
 391         a2 -= 2*M_PI;
 392     if (a2 < -M_PI)
 393         a2 += 2*M_PI;
 394     // find the flatness-weighted bisector angle, unflip if a2 was flipped
 395     // FIXME: when dc->vel is oscillating around the fixed angle, the new_ang flips back and forth. How to avoid this?
 396     double new_ang = a1 + (1 - dc->flatness) * (a2 - a1) - (flipped? M_PI : 0);
 397
 398     // Try to detect a sudden flip when the new angle differs too much from the previous for the
 399     // current velocity; in that case discard this move
 400     double angle_delta = NR::L2(Geom::Point (cos (new_ang), sin (new_ang)) - dc->ang);
 401     if ( angle_delta / NR::L2(dc->vel) > 4000 ) {
 402         return FALSE;
 403     }
 404
 405     // convert to point
 406     dc->ang = Geom::Point (cos (new_ang), sin (new_ang));
 407
 408 //    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);
 409
 410     /* Apply drag */
 411     dc->vel *= 1.0 - drag;
 412
 413     /* Update position */
 414     dc->last = dc->cur;
 415     dc->cur += dc->vel;
 416
 417     return TRUE;
 418 }
 419
 420 static void
 421 sp_dyna_draw_brush(SPDynaDrawContext *dc)
 422 {
 423     g_assert( dc->npoints >= 0 && dc->npoints < SAMPLING_SIZE );
 424
 425     // How much velocity thins strokestyle
 426     double vel_thin = flerp (0, 160, dc->vel_thin);
 427
 428     // Influence of pressure on thickness
 429     double pressure_thick = (dc->usepressure ? dc->pressure : 1.0);
 430
 431     // get the real brush point, not the same as pointer (affected by hatch tracking and/or mass
 432     // drag)
 433     Geom::Point brush = sp_dyna_draw_get_vpoint(dc, dc->cur);
 434     Geom::Point brush_w = SP_EVENT_CONTEXT(dc)->desktop->d2w(brush);
 435
 436     double trace_thick = 1;
 437     if (dc->trace_bg) {
 438         // pick single pixel
 439         NRPixBlock pb;
 440         int x = (int) floor(brush_w[NR::X]);
 441         int y = (int) floor(brush_w[NR::Y]);
 442         nr_pixblock_setup_fast(&pb, NR_PIXBLOCK_MODE_R8G8B8A8P, x, y, x+1, y+1, TRUE);
 443         sp_canvas_arena_render_pixblock(SP_CANVAS_ARENA(sp_desktop_drawing(SP_EVENT_CONTEXT(dc)->desktop)), &pb);
 444         const unsigned char *s = NR_PIXBLOCK_PX(&pb);
 445         double R = s[0] / 255.0;
 446         double G = s[1] / 255.0;
 447         double B = s[2] / 255.0;
 448         double A = s[3] / 255.0;
 449         double max = MAX (MAX (R, G), B);
 450         double min = MIN (MIN (R, G), B);
 451         double L = A * (max + min)/2 + (1 - A); // blend with white bg
 452         trace_thick = 1 - L;
 453         //g_print ("L %g thick %g\n", L, trace_thick);
 454     }
 455
 456     double width = (pressure_thick * trace_thick - vel_thin * NR::L2(dc->vel)) * dc->width;
 457
 458     double tremble_left = 0, tremble_right = 0;
 459     if (dc->tremor > 0) {
 460         // obtain two normally distributed random variables, using polar Box-Muller transform
 461         double x1, x2, w, y1, y2;
 462         do {
 463             x1 = 2.0 * g_random_double_range(0,1) - 1.0;
 464             x2 = 2.0 * g_random_double_range(0,1) - 1.0;
 465             w = x1 * x1 + x2 * x2;
 466         } while ( w >= 1.0 );
 467         w = sqrt( (-2.0 * log( w ) ) / w );
 468         y1 = x1 * w;
 469         y2 = x2 * w;
 470
 471         // deflect both left and right edges randomly and independently, so that:
 472         // (1) dc->tremor=1 corresponds to sigma=1, decreasing dc->tremor narrows the bell curve;
 473         // (2) deflection depends on width, but is upped for small widths for better visual uniformity across widths;
 474         // (3) deflection somewhat depends on speed, to prevent fast strokes looking
 475         // comparatively smooth and slow ones excessively jittery
 476         tremble_left  = (y1)*dc->tremor * (0.15 + 0.8*width) * (0.35 + 14*NR::L2(dc->vel));
 477         tremble_right = (y2)*dc->tremor * (0.15 + 0.8*width) * (0.35 + 14*NR::L2(dc->vel));
 478     }
 479
 480     if ( width < 0.02 * dc->width ) {
 481         width = 0.02 * dc->width;
 482     }
 483
 484     double dezoomify_factor = 0.05 * 1000;
 485     if (!dc->abs_width) {
 486         dezoomify_factor /= SP_EVENT_CONTEXT(dc)->desktop->current_zoom();
 487     }
 488
 489     Geom::Point del_left = dezoomify_factor * (width + tremble_left) * dc->ang;
 490     Geom::Point del_right = dezoomify_factor * (width + tremble_right) * dc->ang;
 491
 492     dc->point1[dc->npoints] = brush + del_left;
 493     dc->point2[dc->npoints] = brush - del_right;
 494
 495     dc->del = 0.5*(del_left + del_right);
 496
 497     dc->npoints++;
 498 }
 499
 500 void
 501 sp_ddc_update_toolbox (SPDesktop *desktop, const gchar *id, double value)
 502 {
 503     desktop->setToolboxAdjustmentValue (id, value);
 504 }
 505
 506 static void
 507 calligraphic_cancel(SPDynaDrawContext *dc)
 508 {
 509     SPDesktop *desktop = SP_EVENT_CONTEXT(dc)->desktop;
 510     dc->dragging = FALSE;
 511     dc->is_drawing = false;
 512     sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate), 0);
 513             /* Remove all temporary line segments */
 514             while (dc->segments) {
 515                 gtk_object_destroy(GTK_OBJECT(dc->segments->data));
 516                 dc->segments = g_slist_remove(dc->segments, dc->segments->data);
 517             }
 518             /* reset accumulated curve */
 519             dc->accumulated->reset();
 520             clear_current(dc);
 521             if (dc->repr) {
 522                 dc->repr = NULL;
 523             }
 524 }
 525
 526
 527 gint
 528 sp_dyna_draw_context_root_handler(SPEventContext *event_context,
 529                                   GdkEvent *event)
 530 {
 531     SPDynaDrawContext *dc = SP_DYNA_DRAW_CONTEXT(event_context);
 532     SPDesktop *desktop = event_context->desktop;
 533
 534     gint ret = FALSE;
 535
 536     switch (event->type) {
 537         case GDK_BUTTON_PRESS:
 538             if (event->button.button == 1 && !event_context->space_panning) {
 539
 540                 SPDesktop *desktop = SP_EVENT_CONTEXT_DESKTOP(dc);
 541
 542                 if (Inkscape::have_viable_layer(desktop, dc->_message_context) == false) {
 543                     return TRUE;
 544                 }
 545
 546                 Geom::Point const button_w(event->button.x,
 547                                          event->button.y);
 548                 Geom::Point const button_dt(desktop->w2d(button_w));
 549                 sp_dyna_draw_reset(dc, button_dt);
 550                 sp_dyna_draw_extinput(dc, event);
 551                 sp_dyna_draw_apply(dc, button_dt);
 552                 dc->accumulated->reset();
 553                 if (dc->repr) {
 554                     dc->repr = NULL;
 555                 }
 556
 557                 /* initialize first point */
 558                 dc->npoints = 0;
 559
 560                 sp_canvas_item_grab(SP_CANVAS_ITEM(desktop->acetate),
 561                                     ( GDK_KEY_PRESS_MASK |
 562                                       GDK_BUTTON_RELEASE_MASK |
 563                                       GDK_POINTER_MOTION_MASK |
 564                                       GDK_BUTTON_PRESS_MASK ),
 565                                     NULL,
 566                                     event->button.time);
 567
 568                 ret = TRUE;
 569
 570                 sp_canvas_force_full_redraw_after_interruptions(desktop->canvas, 3);
 571                 dc->is_drawing = true;
 572             }
 573             break;
 574         case GDK_MOTION_NOTIFY:
 575         {
 576             Geom::Point const motion_w(event->motion.x,
 577                                      event->motion.y);
 578             Geom::Point motion_dt(desktop->w2d(motion_w));
 579             sp_dyna_draw_extinput(dc, event);
 580
 581             dc->_message_context->clear();
 582
 583             // for hatching:
 584             double hatch_dist = 0;
 585             Geom::Point hatch_unit_vector(0,0);
 586             Geom::Point nearest(0,0);
 587             Geom::Point pointer(0,0);
 588             Geom::Matrix motion_to_curve(Geom::identity());
 589
 590             if (event->motion.state & GDK_CONTROL_MASK) { // hatching - sense the item
 591
 592                 SPItem *selected = sp_desktop_selection(desktop)->singleItem();
 593                 if (selected && (SP_IS_SHAPE(selected) || SP_IS_TEXT(selected))) {
 594                     // One item selected, and it's a path;
 595                     // let's try to track it as a guide
 596
 597                     if (selected != dc->hatch_item) {
 598                         dc->hatch_item = selected;
 599                         if (dc->hatch_livarot_path)
 600                             delete dc->hatch_livarot_path;
 601                         dc->hatch_livarot_path = Path_for_item (dc->hatch_item, true, true);
 602                         dc->hatch_livarot_path->ConvertWithBackData(0.01);
 603                     }
 604
 605                     // calculate pointer point in the guide item's coords
 606                     motion_to_curve = sp_item_dt2i_affine(selected) * sp_item_i2doc_affine(selected);
 607                     pointer = motion_dt * motion_to_curve;
 608
 609                     // calculate the nearest point on the guide path
 610                     boost::optional<Path::cut_position> position = get_nearest_position_on_Path(dc->hatch_livarot_path, pointer);
 611                     nearest = get_point_on_Path(dc->hatch_livarot_path, position->piece, position->t);
 612
 613
 614                     // distance from pointer to nearest
 615                     hatch_dist = NR::L2(pointer - nearest);
 616                     // unit-length vector
 617                     hatch_unit_vector = (pointer - nearest)/hatch_dist;
 618
 619                     dc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("<b>Guide path selected</b>; start drawing along the guide with <b>Ctrl</b>"));
 620                 } else {
 621                     dc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("<b>Select a guide path</b> to track with <b>Ctrl</b>"));
 622                 }
 623             }
 624
 625             if ( dc->is_drawing && (event->motion.state & GDK_BUTTON1_MASK) && !event_context->space_panning) {
 626                 dc->dragging = TRUE;
 627
 628                 if (event->motion.state & GDK_CONTROL_MASK && dc->hatch_item) { // hatching
 629
 630 #define SPEED_ELEMENTS 12
 631 #define SPEED_MIN 0.12
 632 #define SPEED_NORMAL 0.65
 633
 634                     // speed is the movement of the nearest point along the guide path, divided by
 635                     // the movement of the pointer at the same period; it is averaged for the last
 636                     // SPEED_ELEMENTS motion events.  Normally, as you track the guide path, speed
 637                     // is about 1, i.e. the nearest point on the path is moved by about the same
 638                     // distance as the pointer. If the speed starts to decrease, we are losing
 639                     // contact with the guide; if it drops below SPEED_MIN, we are on our own and
 640                     // not attracted to guide anymore. Most often this happens when you have
 641                     // tracked to the end of a guide calligraphic stroke and keep moving
 642                     // further. We try to handle this situation gracefully: not stick with the
 643                     // guide forever but let go of it smoothly and without sharp jerks (non-zero
 644                     // mass recommended; with zero mass, jerks are still quite noticeable).
 645
 646                     double speed = 1;
 647                     if (NR::L2(dc->hatch_last_nearest) != 0) {
 648                         // the distance nearest moved since the last motion event
 649                         double nearest_moved = NR::L2(nearest - dc->hatch_last_nearest);
 650                         // the distance pointer moved since the last motion event
 651                         double pointer_moved = NR::L2(pointer - dc->hatch_last_pointer);
 652                         // store them in stacks limited to SPEED_ELEMENTS
 653                         dc->hatch_nearest_past.push_front(nearest_moved);
 654                         if (dc->hatch_nearest_past.size() > SPEED_ELEMENTS)
 655                             dc->hatch_nearest_past.pop_back();
 656                         dc->hatch_pointer_past.push_front(pointer_moved);
 657                         if (dc->hatch_pointer_past.size() > SPEED_ELEMENTS)
 658                             dc->hatch_pointer_past.pop_back();
 659
 660                         // If the stacks are full,
 661                         if (dc->hatch_nearest_past.size() == SPEED_ELEMENTS) {
 662                             // calculate the sums of all stored movements
 663                             double nearest_sum = std::accumulate (dc->hatch_nearest_past.begin(), dc->hatch_nearest_past.end(), 0.0);
 664                             double pointer_sum = std::accumulate (dc->hatch_pointer_past.begin(), dc->hatch_pointer_past.end(), 0.0);
 665                             // and divide to get the speed
 666                             speed = nearest_sum/pointer_sum;
 667                             //g_print ("nearest sum %g  pointer_sum %g  speed %g\n", nearest_sum, pointer_sum, speed);
 668                         }
 669                     }
 670
 671                     if (   dc->hatch_escaped  // already escaped, do not reattach
 672                         || (speed < SPEED_MIN) // stuck; most likely reached end of traced stroke
 673                         || (dc->hatch_spacing > 0 && hatch_dist > 50 * dc->hatch_spacing) // went too far from the guide
 674                         ) {
 675                         // We are NOT attracted to the guide!
 676
 677                         //g_print ("\nlast_nearest %g %g   nearest %g %g  pointer %g %g  pos %d %g\n", dc->last_nearest[NR::X], dc->last_nearest[NR::Y], nearest[NR::X], nearest[NR::Y], pointer[NR::X], pointer[NR::Y], position->piece, position->t);
 678
 679                         // Remember hatch_escaped so we don't get
 680                         // attracted again until the end of this stroke
 681                         dc->hatch_escaped = true;
 682
 683                     } else {
 684
 685                         // Calculate angle cosine of this vector-to-guide and all past vectors
 686                         // summed, to detect if we accidentally flipped to the other side of the
 687                         // guide
 688                         double dot = NR::dot (pointer - nearest, dc->hatch_vector_accumulated);
 689                         dot /= NR::L2(pointer - nearest) * NR::L2(dc->hatch_vector_accumulated);
 690
 691                         if (dc->hatch_spacing != 0) { // spacing was already set
 692                             double target;
 693                             if (speed > SPEED_NORMAL) {
 694                                 // all ok, strictly obey the spacing
 695                                 target = dc->hatch_spacing;
 696                             } else {
 697                                 // looks like we're starting to lose speed,
 698                                 // so _gradually_ let go attraction to prevent jerks
 699                                 target = (dc->hatch_spacing * speed + hatch_dist * (SPEED_NORMAL - speed))/SPEED_NORMAL;
 700                             }
 701                             if (!IS_NAN(dot) && dot < -0.5) {// flip
 702                                 target = -target;
 703                             }
 704
 705                             // This is the track pointer that we will use instead of the real one
 706                             Geom::Point new_pointer = nearest + target * hatch_unit_vector;
 707
 708                             // some limited feedback: allow persistent pulling to slightly change
 709                             // the spacing
 710                             dc->hatch_spacing += (hatch_dist - dc->hatch_spacing)/3500;
 711
 712                             // return it to the desktop coords
 713                             motion_dt = new_pointer * motion_to_curve.inverse();
 714
 715                         } else {
 716                             // this is the first motion event, set the dist
 717                             dc->hatch_spacing = hatch_dist;
 718                         }
 719
 720                         // remember last points
 721                         dc->hatch_last_pointer = pointer;
 722                         dc->hatch_last_nearest = nearest;
 723                         dc->hatch_vector_accumulated += (pointer - nearest);
 724                     }
 725
 726                     dc->_message_context->set(Inkscape::NORMAL_MESSAGE, dc->hatch_escaped? _("Tracking: <b>connection to guide path lost!</b>") : _("<b>Tracking</b> a guide path"));
 727
 728                 } else {
 729                     dc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("<b>Drawing</b> a calligraphic stroke"));
 730                 }
 731
 732                 if (!sp_dyna_draw_apply(dc, motion_dt)) {
 733                     ret = TRUE;
 734                     break;
 735                 }
 736
 737                 if ( dc->cur != dc->last ) {
 738                     sp_dyna_draw_brush(dc);
 739                     g_assert( dc->npoints > 0 );
 740                     fit_and_split(dc, FALSE);
 741                 }
 742                 ret = TRUE;
 743             }
 744
 745             // Draw the hatching circle if necessary
 746             if (event->motion.state & GDK_CONTROL_MASK) {
 747                 if (dc->hatch_spacing == 0 && hatch_dist != 0) {
 748                     // Haven't set spacing yet: gray, center free, update radius live
 749                     Geom::Point c = desktop->w2d(motion_w);
 750                     NR::Matrix const sm (NR::scale(hatch_dist, hatch_dist) * NR::translate(c));
 751                     sp_canvas_item_affine_absolute(dc->hatch_area, sm);
 752                     sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(dc->hatch_area), 0x7f7f7fff, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 753                     sp_canvas_item_show(dc->hatch_area);
 754                 } else if (dc->dragging && !dc->hatch_escaped) {
 755                     // Tracking: green, center snapped, fixed radius
 756                     Geom::Point c = motion_dt;
 757                     NR::Matrix const sm (NR::scale(dc->hatch_spacing, dc->hatch_spacing) * NR::translate(c));
 758                     sp_canvas_item_affine_absolute(dc->hatch_area, sm);
 759                     sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(dc->hatch_area), 0x00FF00ff, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 760                     sp_canvas_item_show(dc->hatch_area);
 761                 } else if (dc->dragging && dc->hatch_escaped) {
 762                     // Tracking escaped: red, center free, fixed radius
 763                     Geom::Point c = desktop->w2d(motion_w);
 764                     NR::Matrix const sm (NR::scale(dc->hatch_spacing, dc->hatch_spacing) * NR::translate(c));
 765
 766                     sp_canvas_item_affine_absolute(dc->hatch_area, sm);
 767                     sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(dc->hatch_area), 0xFF0000ff, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 768                     sp_canvas_item_show(dc->hatch_area);
 769                 } else {
 770                     // Not drawing but spacing set: gray, center snapped, fixed radius
 771                     Geom::Point c = (nearest + dc->hatch_spacing * hatch_unit_vector) * motion_to_curve.inverse();
 772                     if (!IS_NAN(c[NR::X]) && !IS_NAN(c[NR::Y])) {
 773                         NR::Matrix const sm (NR::scale(dc->hatch_spacing, dc->hatch_spacing) * NR::translate(c));
 774                         sp_canvas_item_affine_absolute(dc->hatch_area, sm);
 775                         sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(dc->hatch_area), 0x7f7f7fff, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 776                         sp_canvas_item_show(dc->hatch_area);
 777                     }
 778                 }
 779             } else {
 780                 sp_canvas_item_hide(dc->hatch_area);
 781             }
 782         }
 783         break;
 784
 785
 786     case GDK_BUTTON_RELEASE:
 787     {
 788         Geom::Point const motion_w(event->button.x, event->button.y);
 789         Geom::Point const motion_dt(desktop->w2d(motion_w));
 790
 791         sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate), event->button.time);
 792         sp_canvas_end_forced_full_redraws(desktop->canvas);
 793         dc->is_drawing = false;
 794
 795         if (dc->dragging && event->button.button == 1 && !event_context->space_panning) {
 796             dc->dragging = FALSE;
 797
 798             sp_dyna_draw_apply(dc, motion_dt);
 799
 800             /* Remove all temporary line segments */
 801             while (dc->segments) {
 802                 gtk_object_destroy(GTK_OBJECT(dc->segments->data));
 803                 dc->segments = g_slist_remove(dc->segments, dc->segments->data);
 804             }
 805
 806             /* Create object */
 807             fit_and_split(dc, TRUE);
 808             if (accumulate_calligraphic(dc))
 809                 set_to_accumulated(dc, event->button.state & GDK_SHIFT_MASK); // performs document_done
 810             else
 811                 g_warning ("Failed to create path: invalid data in dc->cal1 or dc->cal2");
 812
 813             /* reset accumulated curve */
 814             dc->accumulated->reset();
 815
 816             clear_current(dc);
 817             if (dc->repr) {
 818                 dc->repr = NULL;
 819             }
 820
 821             if (!dc->hatch_pointer_past.empty()) dc->hatch_pointer_past.clear();
 822             if (!dc->hatch_nearest_past.empty()) dc->hatch_nearest_past.clear();
 823             dc->hatch_last_nearest = Geom::Point(0,0);
 824             dc->hatch_last_pointer = Geom::Point(0,0);
 825             dc->hatch_vector_accumulated = Geom::Point(0,0);
 826             dc->hatch_escaped = false;
 827             dc->hatch_item = NULL;
 828             dc->hatch_livarot_path = NULL;
 829
 830             if (dc->hatch_spacing != 0 && !dc->keep_selected) {
 831                 // we do not select the newly drawn path, so increase spacing by step
 832                 if (dc->hatch_spacing_step == 0) {
 833                     dc->hatch_spacing_step = dc->hatch_spacing;
 834                 }
 835                 dc->hatch_spacing += dc->hatch_spacing_step;
 836             }
 837
 838             dc->_message_context->clear();
 839             ret = TRUE;
 840         }
 841         break;
 842     }
 843
 844     case GDK_KEY_PRESS:
 845         switch (get_group0_keyval (&event->key)) {
 846         case GDK_Up:
 847         case GDK_KP_Up:
 848             if (!MOD__CTRL_ONLY) {
 849                 dc->angle += 5.0;
 850                 if (dc->angle > 90.0)
 851                     dc->angle = 90.0;
 852                 sp_ddc_update_toolbox (desktop, "calligraphy-angle", dc->angle);
 853                 ret = TRUE;
 854             }
 855             break;
 856         case GDK_Down:
 857         case GDK_KP_Down:
 858             if (!MOD__CTRL_ONLY) {
 859                 dc->angle -= 5.0;
 860                 if (dc->angle < -90.0)
 861                     dc->angle = -90.0;
 862                 sp_ddc_update_toolbox (desktop, "calligraphy-angle", dc->angle);
 863                 ret = TRUE;
 864             }
 865             break;
 866         case GDK_Right:
 867         case GDK_KP_Right:
 868             if (!MOD__CTRL_ONLY) {
 869                 dc->width += 0.01;
 870                 if (dc->width > 1.0)
 871                     dc->width = 1.0;
 872                 sp_ddc_update_toolbox (desktop, "altx-calligraphy", dc->width * 100); // the same spinbutton is for alt+x
 873                 ret = TRUE;
 874             }
 875             break;
 876         case GDK_Left:
 877         case GDK_KP_Left:
 878             if (!MOD__CTRL_ONLY) {
 879                 dc->width -= 0.01;
 880                 if (dc->width < 0.01)
 881                     dc->width = 0.01;
 882                 sp_ddc_update_toolbox (desktop, "altx-calligraphy", dc->width * 100);
 883                 ret = TRUE;
 884             }
 885             break;
 886         case GDK_Home:
 887         case GDK_KP_Home:
 888             dc->width = 0.01;
 889             sp_ddc_update_toolbox (desktop, "altx-calligraphy", dc->width * 100);
 890             ret = TRUE;
 891             break;
 892         case GDK_End:
 893         case GDK_KP_End:
 894             dc->width = 1.0;
 895             sp_ddc_update_toolbox (desktop, "altx-calligraphy", dc->width * 100);
 896             ret = TRUE;
 897             break;
 898         case GDK_x:
 899         case GDK_X:
 900             if (MOD__ALT_ONLY) {
 901                 desktop->setToolboxFocusTo ("altx-calligraphy");
 902                 ret = TRUE;
 903             }
 904             break;
 905         case GDK_Escape:
 906             if (dc->is_drawing) {
 907                 // if drawing, cancel, otherwise pass it up for deselecting
 908                 calligraphic_cancel (dc);
 909                 ret = TRUE;
 910             }
 911             break;
 912         case GDK_z:
 913         case GDK_Z:
 914             if (MOD__CTRL_ONLY && dc->is_drawing) {
 915                 // if drawing, cancel, otherwise pass it up for undo
 916                 calligraphic_cancel (dc);
 917                 ret = TRUE;
 918             }
 919             break;
 920         default:
 921             break;
 922         }
 923         break;
 924
 925     case GDK_KEY_RELEASE:
 926         switch (get_group0_keyval(&event->key)) {
 927             case GDK_Control_L:
 928             case GDK_Control_R:
 929                 dc->_message_context->clear();
 930                 dc->hatch_spacing = 0;
 931                 dc->hatch_spacing_step = 0;
 932                 break;
 933             default:
 934                 break;
 935         }
 936
 937     default:
 938         break;
 939     }
 940
 941     if (!ret) {
 942         if (((SPEventContextClass *) dd_parent_class)->root_handler) {
 943             ret = ((SPEventContextClass *) dd_parent_class)->root_handler(event_context, event);
 944         }
 945     }
 946
 947     return ret;
 948 }
 949
 950
 951 static void
 952 clear_current(SPDynaDrawContext *dc)
 953 {
 954     /* reset bpath */
 955     sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(dc->currentshape), NULL);
 956     /* reset curve */
 957     dc->currentcurve->reset();
 958     dc->cal1->reset();
 959     dc->cal2->reset();
 960     /* reset points */
 961     dc->npoints = 0;
 962 }
 963
 964 static void
 965 set_to_accumulated(SPDynaDrawContext *dc, bool unionize)
 966 {
 967     SPDesktop *desktop = SP_EVENT_CONTEXT(dc)->desktop;
 968
 969     if (!dc->accumulated->is_empty()) {
 970         if (!dc->repr) {
 971             /* Create object */
 972             Inkscape::XML::Document *xml_doc = sp_document_repr_doc(desktop->doc());
 973             Inkscape::XML::Node *repr = xml_doc->createElement("svg:path");
 974
 975             /* Set style */
 976             sp_desktop_apply_style_tool (desktop, repr, "tools.calligraphic", false);
 977
 978             dc->repr = repr;
 979
 980             SPItem *item=SP_ITEM(desktop->currentLayer()->appendChildRepr(dc->repr));
 981             Inkscape::GC::release(dc->repr);
 982             item->transform = SP_ITEM(desktop->currentRoot())->getRelativeTransform(desktop->currentLayer());
 983             item->updateRepr();
 984         }
 985         Geom::PathVector pathv = dc->accumulated->get_pathvector() * sp_desktop_dt2root_affine(desktop);
 986         gchar *str = sp_svg_write_path(pathv);
 987         g_assert( str != NULL );
 988         dc->repr->setAttribute("d", str);
 989         g_free(str);
 990
 991         if (unionize) {
 992             sp_desktop_selection(desktop)->add(dc->repr);
 993             sp_selected_path_union_skip_undo(desktop);
 994         } else {
 995             if (dc->keep_selected) {
 996                 sp_desktop_selection(desktop)->set(dc->repr);
 997             }
 998         }
 999
1000     } else {
1001         if (dc->repr) {
1002             sp_repr_unparent(dc->repr);
1003         }
1004         dc->repr = NULL;
1005     }
1006
1007     sp_document_done(sp_desktop_document(desktop), SP_VERB_CONTEXT_CALLIGRAPHIC,
1008                      _("Draw calligraphic stroke"));
1009 }
1010
1011 static void
1012 add_cap(SPCurve *curve,
1013         Geom::Point const &from,
1014         Geom::Point const &to,
1015         double rounding)
1016 {
1017     if (NR::L2( to - from ) > DYNA_EPSILON) {
1018         Geom::Point vel = rounding * NR::rot90( to - from ) / sqrt(2.0);
1019         double mag = NR::L2(vel);
1020
1021         Geom::Point v = mag * NR::rot90( to - from ) / NR::L2( to - from );
1022         curve->curveto(from + v, to + v, to);
1023     }
1024 }
1025
1026 static bool
1027 accumulate_calligraphic(SPDynaDrawContext *dc)
1028 {
1029         if (
1030             dc->cal1->is_empty() ||
1031             dc->cal2->is_empty() ||
1032             (dc->cal1->get_segment_count() <= 0) ||
1033             dc->cal1->first_path()->closed()
1034             ) {
1035             dc->cal1->reset();
1036             dc->cal2->reset();
1037             return false; // failure
1038         }
1039
1040         SPCurve *rev_cal2 = dc->cal2->create_reverse();
1041         if (
1042             (rev_cal2->get_segment_count() <= 0) ||
1043             rev_cal2->first_path()->closed()
1044             ) {
1045             rev_cal2->unref();
1046             dc->cal1->reset();
1047             dc->cal2->reset();
1048             return false; // failure
1049         }
1050
1051         Geom::CubicBezier const * dc_cal1_firstseg  = dynamic_cast<Geom::CubicBezier const *>( dc->cal1->first_segment() );
1052         Geom::CubicBezier const * rev_cal2_firstseg = dynamic_cast<Geom::CubicBezier const *>( rev_cal2->first_segment() );
1053         Geom::CubicBezier const * dc_cal1_lastseg   = dynamic_cast<Geom::CubicBezier const *>( dc->cal1->last_segment() );
1054         Geom::CubicBezier const * rev_cal2_lastseg  = dynamic_cast<Geom::CubicBezier const *>( rev_cal2->last_segment() );
1055
1056         if (
1057             !dc_cal1_firstseg ||
1058             !rev_cal2_firstseg ||
1059             !dc_cal1_lastseg ||
1060             !rev_cal2_lastseg
1061             ) {
1062             rev_cal2->unref();
1063             dc->cal1->reset();
1064             dc->cal2->reset();
1065             return false; // failure
1066         }
1067
1068         dc->accumulated->reset(); /*  Is this required ?? */
1069
1070         dc->accumulated->append(dc->cal1, false);
1071
1072         add_cap(dc->accumulated, (*dc_cal1_lastseg)[3], (*rev_cal2_firstseg)[0], dc->cap_rounding);
1073
1074         dc->accumulated->append(rev_cal2, true);
1075
1076         add_cap(dc->accumulated, (*rev_cal2_lastseg)[3], (*dc_cal1_firstseg)[0], dc->cap_rounding);
1077
1078         dc->accumulated->closepath();
1079
1080         rev_cal2->unref();
1081
1082         dc->cal1->reset();
1083         dc->cal2->reset();
1084
1085         return true; // success
1086 }
1087
1088 static double square(double const x)
1089 {
1090     return x * x;
1091 }
1092
1093 static void
1094 fit_and_split(SPDynaDrawContext *dc, gboolean release)
1095 {
1096     SPDesktop *desktop = SP_EVENT_CONTEXT(dc)->desktop;
1097
1098     double const tolerance_sq = square( NR::expansion(desktop->w2d()) * TOLERANCE_CALLIGRAPHIC );
1099
1100 #ifdef DYNA_DRAW_VERBOSE
1101     g_print("[F&S:R=%c]", release?'T':'F');
1102 #endif
1103
1104     if (!( dc->npoints > 0 && dc->npoints < SAMPLING_SIZE ))
1105         return; // just clicked
1106
1107     if ( dc->npoints == SAMPLING_SIZE - 1 || release ) {
1108 #define BEZIER_SIZE       4
1109 #define BEZIER_MAX_BEZIERS  8
1110 #define BEZIER_MAX_LENGTH ( BEZIER_SIZE * BEZIER_MAX_BEZIERS )
1111
1112 #ifdef DYNA_DRAW_VERBOSE
1113         g_print("[F&S:#] dc->npoints:%d, release:%s\n",
1114                 dc->npoints, release ? "TRUE" : "FALSE");
1115 #endif
1116
1117         /* Current calligraphic */
1118         if ( dc->cal1->is_empty() || dc->cal2->is_empty() ) {
1119             /* dc->npoints > 0 */
1120             /* g_print("calligraphics(1|2) reset\n"); */
1121             dc->cal1->reset();
1122             dc->cal2->reset();
1123
1124             dc->cal1->moveto(dc->point1[0]);
1125             dc->cal2->moveto(dc->point2[0]);
1126         }
1127
1128         Geom::Point b1[BEZIER_MAX_LENGTH];
1129         gint const nb1 = sp_bezier_fit_cubic_r(b1, dc->point1, dc->npoints,
1130                                                tolerance_sq, BEZIER_MAX_BEZIERS);
1131         g_assert( nb1 * BEZIER_SIZE <= gint(G_N_ELEMENTS(b1)) );
1132
1133         Geom::Point b2[BEZIER_MAX_LENGTH];
1134         gint const nb2 = sp_bezier_fit_cubic_r(b2, dc->point2, dc->npoints,
1135                                                tolerance_sq, BEZIER_MAX_BEZIERS);
1136         g_assert( nb2 * BEZIER_SIZE <= gint(G_N_ELEMENTS(b2)) );
1137
1138         if ( nb1 != -1 && nb2 != -1 ) {
1139             /* Fit and draw and reset state */
1140 #ifdef DYNA_DRAW_VERBOSE
1141             g_print("nb1:%d nb2:%d\n", nb1, nb2);
1142 #endif
1143             /* CanvasShape */
1144             if (! release) {
1145                 dc->currentcurve->reset();
1146                 dc->currentcurve->moveto(b1[0]);
1147                 for (Geom::Point *bp1 = b1; bp1 < b1 + BEZIER_SIZE * nb1; bp1 += BEZIER_SIZE) {
1148                     dc->currentcurve->curveto(bp1[1], bp1[2], bp1[3]);
1149                 }
1150                 dc->currentcurve->lineto(b2[BEZIER_SIZE*(nb2-1) + 3]);
1151                 for (Geom::Point *bp2 = b2 + BEZIER_SIZE * ( nb2 - 1 ); bp2 >= b2; bp2 -= BEZIER_SIZE) {
1152                     dc->currentcurve->curveto(bp2[2], bp2[1], bp2[0]);
1153                 }
1154                 // FIXME: dc->segments is always NULL at this point??
1155                 if (!dc->segments) { // first segment
1156                     add_cap(dc->currentcurve, b2[0], b1[0], dc->cap_rounding);
1157                 }
1158                 dc->currentcurve->closepath();
1159                 sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(dc->currentshape), dc->currentcurve);
1160             }
1161
1162             /* Current calligraphic */
1163             for (Geom::Point *bp1 = b1; bp1 < b1 + BEZIER_SIZE * nb1; bp1 += BEZIER_SIZE) {
1164                 dc->cal1->curveto(bp1[1], bp1[2], bp1[3]);
1165             }
1166             for (Geom::Point *bp2 = b2; bp2 < b2 + BEZIER_SIZE * nb2; bp2 += BEZIER_SIZE) {
1167                 dc->cal2->curveto(bp2[1], bp2[2], bp2[3]);
1168             }
1169         } else {
1170             /* fixme: ??? */
1171 #ifdef DYNA_DRAW_VERBOSE
1172             g_print("[fit_and_split] failed to fit-cubic.\n");
1173 #endif
1174             draw_temporary_box(dc);
1175
1176             for (gint i = 1; i < dc->npoints; i++) {
1177                 dc->cal1->lineto(dc->point1[i]);
1178             }
1179             for (gint i = 1; i < dc->npoints; i++) {
1180                 dc->cal2->lineto(dc->point2[i]);
1181             }
1182         }
1183
1184         /* Fit and draw and copy last point */
1185 #ifdef DYNA_DRAW_VERBOSE
1186         g_print("[%d]Yup\n", dc->npoints);
1187 #endif
1188         if (!release) {
1189             g_assert(!dc->currentcurve->is_empty());
1190
1191             SPCanvasItem *cbp = sp_canvas_item_new(sp_desktop_sketch(desktop),
1192                                                    SP_TYPE_CANVAS_BPATH,
1193                                                    NULL);
1194             SPCurve *curve = dc->currentcurve->copy();
1195             sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH (cbp), curve);
1196             curve->unref();
1197
1198             guint32 fillColor = sp_desktop_get_color_tool (desktop, "tools.calligraphic", true);
1199             //guint32 strokeColor = sp_desktop_get_color_tool (desktop, "tools.calligraphic", false);
1200             double opacity = sp_desktop_get_master_opacity_tool (desktop, "tools.calligraphic");
1201             double fillOpacity = sp_desktop_get_opacity_tool (desktop, "tools.calligraphic", true);
1202             //double strokeOpacity = sp_desktop_get_opacity_tool (desktop, "tools.calligraphic", false);
1203             sp_canvas_bpath_set_fill(SP_CANVAS_BPATH(cbp), ((fillColor & 0xffffff00) | SP_COLOR_F_TO_U(opacity*fillOpacity)), SP_WIND_RULE_EVENODD);
1204             //on second thougtht don't do stroke yet because we don't have stoke-width yet and because stoke appears between segments while drawing
1205             //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);
1206             sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(cbp), 0x00000000, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
1207             /* fixme: Cannot we cascade it to root more clearly? */
1208             g_signal_connect(G_OBJECT(cbp), "event", G_CALLBACK(sp_desktop_root_handler), desktop);
1209
1210             dc->segments = g_slist_prepend(dc->segments, cbp);
1211         }
1212
1213         dc->point1[0] = dc->point1[dc->npoints - 1];
1214         dc->point2[0] = dc->point2[dc->npoints - 1];
1215         dc->npoints = 1;
1216     } else {
1217         draw_temporary_box(dc);
1218     }
1219 }
1220
1221 static void
1222 draw_temporary_box(SPDynaDrawContext *dc)
1223 {
1224     dc->currentcurve->reset();
1225
1226     dc->currentcurve->moveto(dc->point2[dc->npoints-1]);
1227     for (gint i = dc->npoints-2; i >= 0; i--) {
1228         dc->currentcurve->lineto(dc->point2[i]);
1229     }
1230     for (gint i = 0; i < dc->npoints; i++) {
1231         dc->currentcurve->lineto(dc->point1[i]);
1232     }
1233
1234     if (dc->npoints >= 2) {
1235         add_cap(dc->currentcurve, dc->point1[dc->npoints-1], dc->point2[dc->npoints-1], dc->cap_rounding);
1236     }
1237
1238     dc->currentcurve->closepath();
1239     sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(dc->currentshape), dc->currentcurve);
1240 }
1241
1242 /*
1243   Local Variables:
1244   mode:c++
1245   c-file-style:"stroustrup"
1246   c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
1247   indent-tabs-mode:nil
1248   fill-column:99
1249   End:
1250 */
1251 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :