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  *
  11  * The original dynadraw code:
  12  *   Paul Haeberli <paul@sgi.com>
  13  *
  14  * Copyright (C) 1998 The Free Software Foundation
  15  * Copyright (C) 1999-2005 authors
  16  * Copyright (C) 2001-2002 Ximian, Inc.
  17  *
  18  * Released under GNU GPL, read the file 'COPYING' for more information
  19  */
  20
  21 #define noDYNA_DRAW_VERBOSE
  22
  23 #include "config.h"
  24
  25 #include <gtk/gtk.h>
  26 #include <gdk/gdkkeysyms.h>
  27
  28 #include "svg/svg.h"
  29 #include "display/canvas-bpath.h"
  30 #include "display/bezier-utils.h"
  31
  32 #include "macros.h"
  33 #include "document.h"
  34 #include "selection.h"
  35 #include "desktop.h"
  36 #include "desktop-events.h"
  37 #include "desktop-handles.h"
  38 #include "desktop-affine.h"
  39 #include "desktop-style.h"
  40 #include "message-context.h"
  41 #include "pixmaps/cursor-calligraphy.xpm"
  42 #include "dyna-draw-context.h"
  43 #include "libnr/n-art-bpath.h"
  44 #include "libnr/nr-path.h"
  45 #include "xml/repr.h"
  46 #include "context-fns.h"
  47 #include "sp-item.h"
  48
  49 #define DDC_RED_RGBA 0xff0000ff
  50 #define DDC_GREEN_RGBA 0x000000ff
  51
  52 #define SAMPLE_TIMEOUT 10
  53 #define TOLERANCE_LINE 1.0
  54 #define TOLERANCE_CALLIGRAPHIC 3.0
  55 #define DYNA_EPSILON 1.0e-6
  56
  57 #define DYNA_MIN_WIDTH 1.0e-6
  58
  59 #define DRAG_MIN 0.0
  60 #define DRAG_DEFAULT 1.0
  61 #define DRAG_MAX 1.0
  62
  63 static void sp_dyna_draw_context_class_init(SPDynaDrawContextClass *klass);
  64 static void sp_dyna_draw_context_init(SPDynaDrawContext *ddc);
  65 static void sp_dyna_draw_context_dispose(GObject *object);
  66
  67 static void sp_dyna_draw_context_setup(SPEventContext *ec);
  68 static void sp_dyna_draw_context_set(SPEventContext *ec, gchar const *key, gchar const *val);
  69 static gint sp_dyna_draw_context_root_handler(SPEventContext *ec, GdkEvent *event);
  70
  71 static void clear_current(SPDynaDrawContext *dc);
  72 static void set_to_accumulated(SPDynaDrawContext *dc);
  73 static void accumulate_calligraphic(SPDynaDrawContext *dc);
  74
  75 static void fit_and_split(SPDynaDrawContext *ddc, gboolean release);
  76 static void fit_and_split_calligraphics(SPDynaDrawContext *ddc, gboolean release);
  77
  78 static void sp_dyna_draw_reset(SPDynaDrawContext *ddc, NR::Point p);
  79 static NR::Point sp_dyna_draw_get_npoint(SPDynaDrawContext const *ddc, NR::Point v);
  80 static NR::Point sp_dyna_draw_get_vpoint(SPDynaDrawContext const *ddc, NR::Point n);
  81 static void draw_temporary_box(SPDynaDrawContext *dc);
  82
  83
  84 static SPEventContextClass *parent_class;
  85
  86 GtkType
  87 sp_dyna_draw_context_get_type(void)
  88 {
  89     static GType type = 0;
  90     if (!type) {
  91         GTypeInfo info = {
  92             sizeof(SPDynaDrawContextClass),
  93             NULL, NULL,
  94             (GClassInitFunc) sp_dyna_draw_context_class_init,
  95             NULL, NULL,
  96             sizeof(SPDynaDrawContext),
  97             4,
  98             (GInstanceInitFunc) sp_dyna_draw_context_init,
  99             NULL,   /* value_table */
 100         };
 101         type = g_type_register_static(SP_TYPE_EVENT_CONTEXT, "SPDynaDrawContext", &info, (GTypeFlags)0);
 102     }
 103     return type;
 104 }
 105
 106 static void
 107 sp_dyna_draw_context_class_init(SPDynaDrawContextClass *klass)
 108 {
 109     GObjectClass *object_class = (GObjectClass *) klass;
 110     SPEventContextClass *event_context_class = (SPEventContextClass *) klass;
 111
 112     parent_class = (SPEventContextClass*)g_type_class_peek_parent(klass);
 113
 114     object_class->dispose = sp_dyna_draw_context_dispose;
 115
 116     event_context_class->setup = sp_dyna_draw_context_setup;
 117     event_context_class->set = sp_dyna_draw_context_set;
 118     event_context_class->root_handler = sp_dyna_draw_context_root_handler;
 119 }
 120
 121 static void
 122 sp_dyna_draw_context_init(SPDynaDrawContext *ddc)
 123 {
 124     SPEventContext *event_context = SP_EVENT_CONTEXT(ddc);
 125
 126     event_context->cursor_shape = cursor_calligraphy_xpm;
 127     event_context->hot_x = 4;
 128     event_context->hot_y = 4;
 129
 130     ddc->accumulated = NULL;
 131     ddc->segments = NULL;
 132     ddc->currentcurve = NULL;
 133     ddc->currentshape = NULL;
 134     ddc->npoints = 0;
 135     ddc->cal1 = NULL;
 136     ddc->cal2 = NULL;
 137     ddc->repr = NULL;
 138
 139     /* DynaDraw values */
 140     ddc->cur = NR::Point(0,0);
 141     ddc->last = NR::Point(0,0);
 142     ddc->vel = NR::Point(0,0);
 143     ddc->acc = NR::Point(0,0);
 144     ddc->ang = NR::Point(0,0);
 145     ddc->del = NR::Point(0,0);
 146
 147     /* attributes */
 148     ddc->use_timeout = FALSE;
 149     ddc->timer_id = 0;
 150     ddc->dragging = FALSE;
 151     ddc->dynahand = FALSE;
 152
 153     ddc->mass = 0.3;
 154     ddc->drag = DRAG_DEFAULT;
 155     ddc->angle = 30.0;
 156     ddc->width = 0.2;
 157
 158     ddc->vel_thin = 0.1;
 159     ddc->flatness = 0.9;
 160 }
 161
 162 static void
 163 sp_dyna_draw_context_dispose(GObject *object)
 164 {
 165     SPDynaDrawContext *ddc = SP_DYNA_DRAW_CONTEXT(object);
 166
 167     if (ddc->accumulated) {
 168         ddc->accumulated = sp_curve_unref(ddc->accumulated);
 169     }
 170
 171     while (ddc->segments) {
 172         gtk_object_destroy(GTK_OBJECT(ddc->segments->data));
 173         ddc->segments = g_slist_remove(ddc->segments, ddc->segments->data);
 174     }
 175
 176     if (ddc->currentcurve) ddc->currentcurve = sp_curve_unref(ddc->currentcurve);
 177     if (ddc->cal1) ddc->cal1 = sp_curve_unref(ddc->cal1);
 178     if (ddc->cal2) ddc->cal2 = sp_curve_unref(ddc->cal2);
 179
 180     if (ddc->currentshape) {
 181         gtk_object_destroy(GTK_OBJECT(ddc->currentshape));
 182         ddc->currentshape = NULL;
 183     }
 184
 185     if (ddc->_message_context) {
 186         delete ddc->_message_context;
 187     }
 188
 189     G_OBJECT_CLASS(parent_class)->dispose(object);
 190 }
 191
 192 static void
 193 sp_dyna_draw_context_setup(SPEventContext *ec)
 194 {
 195     SPDynaDrawContext *ddc = SP_DYNA_DRAW_CONTEXT(ec);
 196
 197     if (((SPEventContextClass *) parent_class)->setup)
 198         ((SPEventContextClass *) parent_class)->setup(ec);
 199
 200     ddc->accumulated = sp_curve_new_sized(32);
 201     ddc->currentcurve = sp_curve_new_sized(4);
 202
 203     ddc->cal1 = sp_curve_new_sized(32);
 204     ddc->cal2 = sp_curve_new_sized(32);
 205
 206     ddc->currentshape = sp_canvas_item_new(SP_DT_SKETCH(ec->desktop), SP_TYPE_CANVAS_BPATH, NULL);
 207     sp_canvas_bpath_set_fill(SP_CANVAS_BPATH(ddc->currentshape), DDC_RED_RGBA, SP_WIND_RULE_EVENODD);
 208     sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(ddc->currentshape), 0x00000000, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 209     /* fixme: Cannot we cascade it to root more clearly? */
 210     g_signal_connect(G_OBJECT(ddc->currentshape), "event", G_CALLBACK(sp_desktop_root_handler), ec->desktop);
 211
 212     sp_event_context_read(ec, "mass");
 213     sp_event_context_read(ec, "drag");
 214     sp_event_context_read(ec, "angle");
 215     sp_event_context_read(ec, "width");
 216     sp_event_context_read(ec, "thinning");
 217     sp_event_context_read(ec, "tremor");
 218     sp_event_context_read(ec, "flatness");
 219     sp_event_context_read(ec, "usepressure");
 220     sp_event_context_read(ec, "usetilt");
 221
 222     ddc->is_drawing = false;
 223
 224     ddc->_message_context = new Inkscape::MessageContext((ec->desktop)->messageStack());
 225 }
 226
 227 static void
 228 sp_dyna_draw_context_set(SPEventContext *ec, gchar const *key, gchar const *val)
 229 {
 230     SPDynaDrawContext *ddc = SP_DYNA_DRAW_CONTEXT(ec);
 231
 232     if (!strcmp(key, "mass")) {
 233         double const dval = ( val ? g_ascii_strtod (val, NULL) : 0.2 );
 234         ddc->mass = CLAMP(dval, -1000.0, 1000.0);
 235     } else if (!strcmp(key, "drag")) {
 236         double const dval = ( val ? g_ascii_strtod (val, NULL) : DRAG_DEFAULT );
 237         ddc->drag = CLAMP(dval, DRAG_MIN, DRAG_MAX);
 238     } else if (!strcmp(key, "angle")) {
 239         double const dval = ( val ? g_ascii_strtod (val, NULL) : 0.0);
 240         ddc->angle = CLAMP (dval, -90, 90);
 241     } else if (!strcmp(key, "width")) {
 242         double const dval = ( val ? g_ascii_strtod (val, NULL) : 0.1 );
 243         ddc->width = CLAMP(dval, -1000.0, 1000.0);
 244     } else if (!strcmp(key, "thinning")) {
 245         double const dval = ( val ? g_ascii_strtod (val, NULL) : 0.1 );
 246         ddc->vel_thin = CLAMP(dval, -1.0, 1.0);
 247     } else if (!strcmp(key, "tremor")) {
 248         double const dval = ( val ? g_ascii_strtod (val, NULL) : 0.0 );
 249         ddc->tremor = CLAMP(dval, 0.0, 1.0);
 250     } else if (!strcmp(key, "flatness")) {
 251         double const dval = ( val ? g_ascii_strtod (val, NULL) : 1.0 );
 252         ddc->flatness = CLAMP(dval, 0, 1.0);
 253     } else if (!strcmp(key, "usepressure")) {
 254         ddc->usepressure = (val && strcmp(val, "0"));
 255     } else if (!strcmp(key, "usetilt")) {
 256         ddc->usetilt = (val && strcmp(val, "0"));
 257     }
 258
 259     //g_print("DDC: %g %g %g %g\n", ddc->mass, ddc->drag, ddc->angle, ddc->width);
 260 }
 261
 262 static double
 263 flerp(double f0, double f1, double p)
 264 {
 265     return f0 + ( f1 - f0 ) * p;
 266 }
 267
 268 /* Get normalized point */
 269 static NR::Point
 270 sp_dyna_draw_get_npoint(SPDynaDrawContext const *dc, NR::Point v)
 271 {
 272     NR::Rect drect = SP_EVENT_CONTEXT(dc)->desktop->get_display_area();
 273     double const max = MAX ( drect.dimensions()[NR::X], drect.dimensions()[NR::Y] );
 274     return NR::Point(( v[NR::X] - drect.min()[NR::X] ) / max,  ( v[NR::Y] - drect.min()[NR::Y] ) / max);
 275 }
 276
 277 /* Get view point */
 278 static NR::Point
 279 sp_dyna_draw_get_vpoint(SPDynaDrawContext const *dc, NR::Point n)
 280 {
 281     NR::Rect drect = SP_EVENT_CONTEXT(dc)->desktop->get_display_area();
 282     double const max = MAX ( drect.dimensions()[NR::X], drect.dimensions()[NR::Y] );
 283     return NR::Point(n[NR::X] * max + drect.min()[NR::X], n[NR::Y] * max + drect.min()[NR::Y]);
 284 }
 285
 286 static void
 287 sp_dyna_draw_reset(SPDynaDrawContext *dc, NR::Point p)
 288 {
 289     dc->last = dc->cur = sp_dyna_draw_get_npoint(dc, p);
 290     dc->vel = NR::Point(0,0);
 291     dc->acc = NR::Point(0,0);
 292     dc->ang = NR::Point(0,0);
 293     dc->del = NR::Point(0,0);
 294 }
 295
 296 static void
 297 sp_dyna_draw_extinput(SPDynaDrawContext *dc, GdkEvent *event)
 298 {
 299     if (gdk_event_get_axis (event, GDK_AXIS_PRESSURE, &dc->pressure))
 300         dc->pressure = CLAMP (dc->pressure, DDC_MIN_PRESSURE, DDC_MAX_PRESSURE);
 301     else
 302         dc->pressure = DDC_DEFAULT_PRESSURE;
 303
 304     if (gdk_event_get_axis (event, GDK_AXIS_XTILT, &dc->xtilt))
 305         dc->xtilt = CLAMP (dc->xtilt, DDC_MIN_TILT, DDC_MAX_TILT);
 306     else
 307         dc->xtilt = DDC_DEFAULT_TILT;
 308
 309     if (gdk_event_get_axis (event, GDK_AXIS_YTILT, &dc->ytilt))
 310         dc->ytilt = CLAMP (dc->ytilt, DDC_MIN_TILT, DDC_MAX_TILT);
 311     else
 312         dc->ytilt = DDC_DEFAULT_TILT;
 313 }
 314
 315
 316 static gboolean
 317 sp_dyna_draw_apply(SPDynaDrawContext *dc, NR::Point p)
 318 {
 319     NR::Point n = sp_dyna_draw_get_npoint(dc, p);
 320
 321     /* Calculate mass and drag */
 322     double const mass = flerp(1.0, 160.0, dc->mass);
 323     double const drag = flerp(0.0, 0.5, dc->drag * dc->drag);
 324
 325     /* Calculate force and acceleration */
 326     NR::Point force = n - dc->cur;
 327     if ( NR::L2(force) < DYNA_EPSILON ) {
 328         return FALSE;
 329     }
 330
 331     dc->acc = force / mass;
 332
 333     /* Calculate new velocity */
 334     dc->vel += dc->acc;
 335
 336     /* Calculate angle of drawing tool */
 337
 338     double a1;
 339     if (dc->usetilt) {
 340         // 1a. calculate nib angle from input device tilt:
 341         gdouble length = std::sqrt(dc->xtilt*dc->xtilt + dc->ytilt*dc->ytilt);;
 342
 343         if (length > 0) {
 344             NR::Point ang1 = NR::Point(dc->ytilt/length, dc->xtilt/length);
 345             a1 = atan2(ang1);
 346         }
 347         else
 348             a1 = 0.0;
 349     }
 350     else {
 351         // 1b. fixed dc->angle (absolutely flat nib):
 352         double const radians = ( (dc->angle - 90) / 180.0 ) * M_PI;
 353         NR::Point ang1 = NR::Point(-sin(radians),  cos(radians));
 354         a1 = atan2(ang1);
 355     }
 356
 357     // 2. perpendicular to dc->vel (absolutely non-flat nib):
 358     gdouble const mag_vel = NR::L2(dc->vel);
 359     if ( mag_vel < DYNA_EPSILON ) {
 360         return FALSE;
 361     }
 362     NR::Point ang2 = NR::rot90(dc->vel) / mag_vel;
 363
 364     // 3. Average them using flatness parameter:
 365     // calculate angles
 366     double a2 = atan2(ang2);
 367     // flip a2 to force it to be in the same half-circle as a1
 368     bool flipped = false;
 369     if (fabs (a2-a1) > 0.5*M_PI) {
 370         a2 += M_PI;
 371         flipped = true;
 372     }
 373     // normalize a2
 374     if (a2 > M_PI)
 375         a2 -= 2*M_PI;
 376     if (a2 < -M_PI)
 377         a2 += 2*M_PI;
 378     // find the flatness-weighted bisector angle, unflip if a2 was flipped
 379     // FIXME: when dc->vel is oscillating around the fixed angle, the new_ang flips back and forth. How to avoid this?
 380     double new_ang = a1 + (1 - dc->flatness) * (a2 - a1) - (flipped? M_PI : 0);
 381     // convert to point
 382     dc->ang = NR::Point (cos (new_ang), sin (new_ang));
 383
 384     /* Apply drag */
 385     dc->vel *= 1.0 - drag;
 386
 387     /* Update position */
 388     dc->last = dc->cur;
 389     dc->cur += dc->vel;
 390
 391     return TRUE;
 392 }
 393
 394 static void
 395 sp_dyna_draw_brush(SPDynaDrawContext *dc)
 396 {
 397     g_assert( dc->npoints >= 0 && dc->npoints < SAMPLING_SIZE );
 398
 399     // How much velocity thins strokestyle
 400     double vel_thin = flerp (0, 160, dc->vel_thin);
 401
 402     // Influence of pressure on thickness
 403     double pressure_thick = (dc->usepressure ? dc->pressure : 1.0);
 404
 405     double width = ( pressure_thick - vel_thin * NR::L2(dc->vel) ) * dc->width;
 406
 407     double tremble_left = 0, tremble_right = 0;
 408     if (dc->tremor > 0) {
 409         // obtain two normally distributed random variables, using polar Box-Muller transform
 410         double x1, x2, w, y1, y2;
 411         do {
 412             x1 = 2.0 * g_random_double_range(0,1) - 1.0;
 413             x2 = 2.0 * g_random_double_range(0,1) - 1.0;
 414             w = x1 * x1 + x2 * x2;
 415         } while ( w >= 1.0 );
 416         w = sqrt( (-2.0 * log( w ) ) / w );
 417         y1 = x1 * w;
 418         y2 = x2 * w;
 419
 420         // deflect both left and right edges randomly and independently, so that:
 421         // (1) dc->tremor=1 corresponds to sigma=1, decreasing dc->tremor narrows the bell curve;
 422         // (2) deflection depends on width, but is upped for small widths for better visual uniformity across widths;
 423         // (3) deflection somewhat depends on speed, to prevent fast strokes looking
 424         // comparatively smooth and slow ones excessively jittery
 425         tremble_left  = (y1)*dc->tremor * (0.15 + 0.8*width) * (0.35 + 14*NR::L2(dc->vel));
 426         tremble_right = (y2)*dc->tremor * (0.15 + 0.8*width) * (0.35 + 14*NR::L2(dc->vel));
 427     }
 428
 429     if ( width < 0.02 * dc->width ) {
 430         width = 0.02 * dc->width;
 431     }
 432
 433     NR::Point del_left = 0.05 * (width + tremble_left) * dc->ang;
 434     NR::Point del_right = 0.05 * (width + tremble_right) * dc->ang;
 435
 436     dc->point1[dc->npoints] = sp_dyna_draw_get_vpoint(dc, dc->cur + del_left);
 437     dc->point2[dc->npoints] = sp_dyna_draw_get_vpoint(dc, dc->cur - del_right);
 438
 439     dc->del = 0.5*(del_left + del_right);
 440
 441     dc->npoints++;
 442 }
 443
 444 static gint
 445 sp_dyna_draw_timeout_handler(gpointer data)
 446 {
 447     SPDynaDrawContext *dc = SP_DYNA_DRAW_CONTEXT(data);
 448     SPDesktop *desktop = SP_EVENT_CONTEXT(dc)->desktop;
 449     SPCanvas *canvas = SP_CANVAS(SP_DT_CANVAS(desktop));
 450
 451     dc->dragging = TRUE;
 452     dc->dynahand = TRUE;
 453
 454     int x, y;
 455     gtk_widget_get_pointer(GTK_WIDGET(canvas), &x, &y);
 456     NR::Point p = sp_canvas_window_to_world(canvas, NR::Point(x, y));
 457     p = desktop->w2d(p);
 458     if (! sp_dyna_draw_apply(dc, p)) {
 459         return TRUE;
 460     }
 461
 462     if ( dc->cur != dc->last ) {
 463         sp_dyna_draw_brush(dc);
 464         g_assert( dc->npoints > 0 );
 465         fit_and_split(dc, FALSE);
 466     }
 467
 468     return TRUE;
 469 }
 470
 471 void
 472 sp_ddc_update_toolbox (SPDesktop *desktop, const gchar *id, double value)
 473 {
 474     desktop->setToolboxAdjustmentValue (id, value);
 475 }
 476
 477 gint
 478 sp_dyna_draw_context_root_handler(SPEventContext *event_context,
 479                                   GdkEvent *event)
 480 {
 481     SPDynaDrawContext *dc = SP_DYNA_DRAW_CONTEXT(event_context);
 482     SPDesktop *desktop = event_context->desktop;
 483
 484     gint ret = FALSE;
 485
 486     switch (event->type) {
 487     case GDK_BUTTON_PRESS:
 488         if ( event->button.button == 1 ) {
 489
 490             SPDesktop *desktop = SP_EVENT_CONTEXT_DESKTOP(dc);
 491
 492             if (Inkscape::have_viable_layer(desktop, dc->_message_context) == false) {
 493                 return TRUE;
 494             }
 495
 496             NR::Point const button_w(event->button.x,
 497                                      event->button.y);
 498             NR::Point const button_dt(desktop->w2d(button_w));
 499             sp_dyna_draw_reset(dc, button_dt);
 500             sp_dyna_draw_extinput(dc, event);
 501             sp_dyna_draw_apply(dc, button_dt);
 502             sp_curve_reset(dc->accumulated);
 503             if (dc->repr) {
 504                 dc->repr = NULL;
 505             }
 506
 507             /* initialize first point */
 508             dc->npoints = 0;
 509
 510             sp_canvas_item_grab(SP_CANVAS_ITEM(desktop->acetate),
 511                                 ( dc->use_timeout
 512                                   ? ( GDK_KEY_PRESS_MASK |
 513                                       GDK_BUTTON_RELEASE_MASK |
 514                                       GDK_BUTTON_PRESS_MASK    )
 515                                   : ( GDK_KEY_PRESS_MASK |
 516                                       GDK_BUTTON_RELEASE_MASK |
 517                                       GDK_POINTER_MOTION_MASK |
 518                                       GDK_BUTTON_PRESS_MASK    ) ),
 519                                 NULL,
 520                                 event->button.time);
 521
 522             if ( dc->use_timeout && !dc->timer_id ) {
 523                 dc->timer_id = gtk_timeout_add(SAMPLE_TIMEOUT, sp_dyna_draw_timeout_handler, dc);
 524             }
 525             ret = TRUE;
 526
 527             dc->is_drawing = true;
 528         }
 529         break;
 530     case GDK_MOTION_NOTIFY:
 531         if ( dc->is_drawing && !dc->use_timeout && ( event->motion.state & GDK_BUTTON1_MASK ) ) {
 532             dc->dragging = TRUE;
 533             dc->dynahand = TRUE;
 534
 535             NR::Point const motion_w(event->motion.x,
 536                                      event->motion.y);
 537             NR::Point const motion_dt(desktop->w2d(motion_w));
 538
 539             sp_dyna_draw_extinput(dc, event);
 540             if (!sp_dyna_draw_apply(dc, motion_dt)) {
 541                 ret = TRUE;
 542                 break;
 543             }
 544
 545             if ( dc->cur != dc->last ) {
 546                 sp_dyna_draw_brush(dc);
 547                 g_assert( dc->npoints > 0 );
 548                 fit_and_split(dc, FALSE);
 549             }
 550             ret = TRUE;
 551         }
 552         break;
 553
 554     case GDK_BUTTON_RELEASE:
 555         sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate), event->button.time);
 556         dc->is_drawing = false;
 557         if ( event->button.button == 1
 558              && dc->use_timeout
 559              && dc->timer_id != 0 )
 560         {
 561             gtk_timeout_remove(dc->timer_id);
 562             dc->timer_id = 0;
 563         }
 564         if ( dc->dragging && event->button.button == 1 ) {
 565             dc->dragging = FALSE;
 566
 567             /* release */
 568             if (dc->dynahand) {
 569                 dc->dynahand = FALSE;
 570                 /* Remove all temporary line segments */
 571                 while (dc->segments) {
 572                     gtk_object_destroy(GTK_OBJECT(dc->segments->data));
 573                     dc->segments = g_slist_remove(dc->segments, dc->segments->data);
 574                 }
 575                 /* Create object */
 576                 fit_and_split(dc, TRUE);
 577                 accumulate_calligraphic(dc);
 578                 set_to_accumulated(dc); /* temporal implementation */
 579                 /* reset accumulated curve */
 580                 sp_curve_reset(dc->accumulated);
 581                 clear_current(dc);
 582                 if (dc->repr) {
 583                     dc->repr = NULL;
 584                 }
 585             }
 586             ret = TRUE;
 587         }
 588         break;
 589     case GDK_KEY_PRESS:
 590         switch (get_group0_keyval (&event->key)) {
 591         case GDK_Up:
 592         case GDK_KP_Up:
 593             if (!MOD__CTRL_ONLY) {
 594                 dc->angle += 5.0;
 595                 if (dc->angle > 90.0)
 596                     dc->angle = 90.0;
 597                 sp_ddc_update_toolbox (desktop, "calligraphy-angle", dc->angle);
 598                 ret = TRUE;
 599             }
 600             break;
 601         case GDK_Down:
 602         case GDK_KP_Down:
 603             if (!MOD__CTRL_ONLY) {
 604                 dc->angle -= 5.0;
 605                 if (dc->angle < -90.0)
 606                     dc->angle = -90.0;
 607                 sp_ddc_update_toolbox (desktop, "calligraphy-angle", dc->angle);
 608                 ret = TRUE;
 609             }
 610             break;
 611         case GDK_Right:
 612         case GDK_KP_Right:
 613             if (!MOD__CTRL_ONLY) {
 614                 dc->width += 0.01;
 615                 if (dc->width > 1.0)
 616                     dc->width = 1.0;
 617                 sp_ddc_update_toolbox (desktop, "altx-calligraphy", dc->width); // the same spinbutton is for alt+x
 618                 ret = TRUE;
 619             }
 620             break;
 621         case GDK_Left:
 622         case GDK_KP_Left:
 623             if (!MOD__CTRL_ONLY) {
 624                 dc->width -= 0.01;
 625                 if (dc->width < 0.01)
 626                     dc->width = 0.01;
 627                 sp_ddc_update_toolbox (desktop, "altx-calligraphy", dc->width);
 628                 ret = TRUE;
 629             }
 630             break;
 631         case GDK_x:
 632         case GDK_X:
 633             if (MOD__ALT_ONLY) {
 634                 desktop->setToolboxFocusTo ("altx-calligraphy");
 635                 ret = TRUE;
 636             }
 637             break;
 638         case GDK_Escape:
 639             SP_DT_SELECTION(desktop)->clear();
 640             break;
 641
 642         default:
 643             break;
 644         }
 645     default:
 646         break;
 647     }
 648
 649     if (!ret) {
 650         if (((SPEventContextClass *) parent_class)->root_handler) {
 651             ret = ((SPEventContextClass *) parent_class)->root_handler(event_context, event);
 652         }
 653     }
 654
 655     return ret;
 656 }
 657
 658
 659 static void
 660 clear_current(SPDynaDrawContext *dc)
 661 {
 662     /* reset bpath */
 663     sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(dc->currentshape), NULL);
 664     /* reset curve */
 665     sp_curve_reset(dc->currentcurve);
 666     sp_curve_reset(dc->cal1);
 667     sp_curve_reset(dc->cal2);
 668     /* reset points */
 669     dc->npoints = 0;
 670 }
 671
 672 static void
 673 set_to_accumulated(SPDynaDrawContext *dc)
 674 {
 675     SPDesktop *desktop = SP_EVENT_CONTEXT(dc)->desktop;
 676
 677     if (!sp_curve_empty(dc->accumulated)) {
 678         NArtBpath *abp;
 679         gchar *str;
 680
 681         if (!dc->repr) {
 682             /* Create object */
 683             Inkscape::XML::Node *repr = sp_repr_new("svg:path");
 684
 685             /* Set style */
 686             sp_desktop_apply_style_tool (desktop, repr, "tools.calligraphic", false);
 687
 688             dc->repr = repr;
 689
 690             SPItem *item=SP_ITEM(desktop->currentLayer()->appendChildRepr(dc->repr));
 691             Inkscape::GC::release(dc->repr);
 692             item->transform = SP_ITEM(desktop->currentRoot())->getRelativeTransform(desktop->currentLayer());
 693             item->updateRepr();
 694             SP_DT_SELECTION(desktop)->set(dc->repr);
 695         }
 696         abp = nr_artpath_affine(sp_curve_first_bpath(dc->accumulated), sp_desktop_dt2root_affine(desktop));
 697         str = sp_svg_write_path(abp);
 698         g_assert( str != NULL );
 699         nr_free(abp);
 700         dc->repr->setAttribute("d", str);
 701         g_free(str);
 702     } else {
 703         if (dc->repr) {
 704             sp_repr_unparent(dc->repr);
 705         }
 706         dc->repr = NULL;
 707     }
 708
 709     sp_document_done(SP_DT_DOCUMENT(desktop));
 710 }
 711
 712 static void
 713 accumulate_calligraphic(SPDynaDrawContext *dc)
 714 {
 715     if ( !sp_curve_empty(dc->cal1) && !sp_curve_empty(dc->cal2) ) {
 716         sp_curve_reset(dc->accumulated); /*  Is this required ?? */
 717         SPCurve *rev_cal2 = sp_curve_reverse(dc->cal2);
 718         sp_curve_append(dc->accumulated, dc->cal1, FALSE);
 719         sp_curve_append(dc->accumulated, rev_cal2, TRUE);
 720         sp_curve_closepath(dc->accumulated);
 721
 722         sp_curve_unref(rev_cal2);
 723
 724         sp_curve_reset(dc->cal1);
 725         sp_curve_reset(dc->cal2);
 726     }
 727 }
 728
 729 static void
 730 fit_and_split(SPDynaDrawContext *dc,
 731               gboolean release)
 732 {
 733     fit_and_split_calligraphics(dc, release);
 734 }
 735
 736 static double square(double const x)
 737 {
 738     return x * x;
 739 }
 740
 741 static void
 742 fit_and_split_calligraphics(SPDynaDrawContext *dc, gboolean release)
 743 {
 744     double const tolerance_sq = square( NR::expansion(SP_EVENT_CONTEXT(dc)->desktop->w2d()) * TOLERANCE_CALLIGRAPHIC );
 745
 746 #ifdef DYNA_DRAW_VERBOSE
 747     g_print("[F&S:R=%c]", release?'T':'F');
 748 #endif
 749
 750     if (!( dc->npoints > 0 && dc->npoints < SAMPLING_SIZE ))
 751         return; // just clicked
 752
 753     if ( dc->npoints == SAMPLING_SIZE - 1 || release ) {
 754 #define BEZIER_SIZE       4
 755 #define BEZIER_MAX_BEZIERS  8
 756 #define BEZIER_MAX_LENGTH ( BEZIER_SIZE * BEZIER_MAX_BEZIERS )
 757
 758 #ifdef DYNA_DRAW_VERBOSE
 759         g_print("[F&S:#] dc->npoints:%d, release:%s\n",
 760                 dc->npoints, release ? "TRUE" : "FALSE");
 761 #endif
 762
 763         /* Current calligraphic */
 764         if ( dc->cal1->end == 0 || dc->cal2->end == 0 ) {
 765             /* dc->npoints > 0 */
 766             /* g_print("calligraphics(1|2) reset\n"); */
 767             sp_curve_reset(dc->cal1);
 768             sp_curve_reset(dc->cal2);
 769
 770             sp_curve_moveto(dc->cal1, dc->point1[0]);
 771             sp_curve_moveto(dc->cal2, dc->point2[0]);
 772         }
 773
 774         NR::Point b1[BEZIER_MAX_LENGTH];
 775         gint const nb1 = sp_bezier_fit_cubic_r(b1, dc->point1, dc->npoints,
 776                                                tolerance_sq, BEZIER_MAX_BEZIERS);
 777         g_assert( nb1 * BEZIER_SIZE <= gint(G_N_ELEMENTS(b1)) );
 778
 779         NR::Point b2[BEZIER_MAX_LENGTH];
 780         gint const nb2 = sp_bezier_fit_cubic_r(b2, dc->point2, dc->npoints,
 781                                                tolerance_sq, BEZIER_MAX_BEZIERS);
 782         g_assert( nb2 * BEZIER_SIZE <= gint(G_N_ELEMENTS(b2)) );
 783
 784         if ( nb1 != -1 && nb2 != -1 ) {
 785             /* Fit and draw and reset state */
 786 #ifdef DYNA_DRAW_VERBOSE
 787             g_print("nb1:%d nb2:%d\n", nb1, nb2);
 788 #endif
 789             /* CanvasShape */
 790             if (! release) {
 791                 sp_curve_reset(dc->currentcurve);
 792                 sp_curve_moveto(dc->currentcurve, b1[0]);
 793                 for (NR::Point *bp1 = b1; bp1 < b1 + BEZIER_SIZE * nb1; bp1 += BEZIER_SIZE) {
 794                     sp_curve_curveto(dc->currentcurve, bp1[1],
 795                                      bp1[2], bp1[3]);
 796                 }
 797                 sp_curve_lineto(dc->currentcurve,
 798                                 b2[BEZIER_SIZE*(nb2-1) + 3]);
 799                 for (NR::Point *bp2 = b2 + BEZIER_SIZE * ( nb2 - 1 ); bp2 >= b2; bp2 -= BEZIER_SIZE) {
 800                     sp_curve_curveto(dc->currentcurve, bp2[2], bp2[1], bp2[0]);
 801                 }
 802                 sp_curve_closepath(dc->currentcurve);
 803                 sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(dc->currentshape), dc->currentcurve);
 804             }
 805
 806             /* Current calligraphic */
 807             for (NR::Point *bp1 = b1; bp1 < b1 + BEZIER_SIZE * nb1; bp1 += BEZIER_SIZE) {
 808                 sp_curve_curveto(dc->cal1, bp1[1], bp1[2], bp1[3]);
 809             }
 810             for (NR::Point *bp2 = b2; bp2 < b2 + BEZIER_SIZE * nb2; bp2 += BEZIER_SIZE) {
 811                 sp_curve_curveto(dc->cal2, bp2[1], bp2[2], bp2[3]);
 812             }
 813         } else {
 814             /* fixme: ??? */
 815 #ifdef DYNA_DRAW_VERBOSE
 816             g_print("[fit_and_split_calligraphics] failed to fit-cubic.\n");
 817 #endif
 818             draw_temporary_box(dc);
 819
 820             for (gint i = 1; i < dc->npoints; i++) {
 821                 sp_curve_lineto(dc->cal1, dc->point1[i]);
 822             }
 823             for (gint i = 1; i < dc->npoints; i++) {
 824                 sp_curve_lineto(dc->cal2, dc->point2[i]);
 825             }
 826         }
 827
 828         /* Fit and draw and copy last point */
 829 #ifdef DYNA_DRAW_VERBOSE
 830         g_print("[%d]Yup\n", dc->npoints);
 831 #endif
 832         if (!release) {
 833             g_assert(!sp_curve_empty(dc->currentcurve));
 834
 835             SPCanvasItem *cbp = sp_canvas_item_new(SP_DT_SKETCH(SP_EVENT_CONTEXT(dc)->desktop),
 836                                                    SP_TYPE_CANVAS_BPATH,
 837                                                    NULL);
 838             SPCurve *curve = sp_curve_copy(dc->currentcurve);
 839             sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH (cbp), curve);
 840             sp_curve_unref(curve);
 841             sp_canvas_bpath_set_fill(SP_CANVAS_BPATH(cbp), 0x000000ff, SP_WIND_RULE_EVENODD);
 842             sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(cbp), 0x00000000, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 843             /* fixme: Cannot we cascade it to root more clearly? */
 844             g_signal_connect(G_OBJECT(cbp), "event", G_CALLBACK(sp_desktop_root_handler), SP_EVENT_CONTEXT(dc)->desktop);
 845
 846             dc->segments = g_slist_prepend(dc->segments, cbp);
 847         }
 848
 849         dc->point1[0] = dc->point1[dc->npoints - 1];
 850         dc->point2[0] = dc->point2[dc->npoints - 1];
 851         dc->npoints = 1;
 852     } else {
 853         draw_temporary_box(dc);
 854     }
 855 }
 856
 857 static void
 858 draw_temporary_box(SPDynaDrawContext *dc)
 859 {
 860     sp_curve_reset(dc->currentcurve);
 861     sp_curve_moveto(dc->currentcurve, dc->point1[0]);
 862     for (gint i = 1; i < dc->npoints; i++) {
 863         sp_curve_lineto(dc->currentcurve, dc->point1[i]);
 864     }
 865     for (gint i = dc->npoints-1; i >= 0; i--) {
 866         sp_curve_lineto(dc->currentcurve, dc->point2[i]);
 867     }
 868     sp_curve_closepath(dc->currentcurve);
 869     sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(dc->currentshape), dc->currentcurve);
 870 }
 871
 872 /*
 873   Local Variables:
 874   mode:c++
 875   c-file-style:"stroustrup"
 876   c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
 877   indent-tabs-mode:nil
 878   fill-column:99
 879   End:
 880 */
 881 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :