src/swfc-history.c

   1 /* swfc- Compiles swf code (.sc) files into .swf files.
   2
   3    Part of the swftools package.
   4
   5    Copyright (c) 2007 Huub Schaeks <huub@h-schaeks.speedlinq.nl>
   6    Copyright (c) 2007 Matthias Kramm <kramm@quiss.org>
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
  21
  22 #include <stdlib.h>
  23 #include <memory.h>
  24 #include "swfc-history.h"
  25
  26 enum
  27 {
  28     T_BEFORE,
  29     T_AFTER,
  30     T_SYMMETRIC
  31 };
  32
  33 state_t* state_new(U16 frame, int function, float value, interpolation_t* inter)
  34 {
  35     state_t* newState = (state_t*)malloc(sizeof(state_t));
  36     state_init(newState);
  37     newState->frame = frame;
  38     newState->function = function;
  39     newState->value = value;
  40     newState->interpolation = inter;
  41     return newState;
  42 }
  43
  44 void state_free(state_t* state)
  45 {
  46     if (state->next)
  47         state_free(state->next);
  48     free(state);
  49 }
  50
  51 void state_init(state_t* state)
  52 {
  53     memset(state, 0, sizeof(state_t));
  54 }
  55
  56 state_t* state_at(state_t* state, U16 frame)
  57 {
  58     while (state->next && state->next->frame < frame)
  59         state = state->next;
  60     return state;
  61 }
  62
  63 void state_append(state_t* state, state_t* newState)
  64 {
  65     state_t* previous = 0;
  66     state_t* start = state;
  67     float p0, p1, m0, m1;
  68     int previous_frames = 0, state_frames, new_frames;
  69
  70     while (state->next)
  71     {
  72         if (previous)
  73             previous_frames = state->frame - previous->frame;
  74         previous = state;
  75         state = state->next;
  76     }
  77     state->next = newState;
  78     new_frames = newState->frame - state->frame;
  79     if (state->function == CF_SCHANGE)
  80     {
  81         state_frames = state->frame - previous->frame;
  82         p0 = previous->value;
  83         p1 = state->value;
  84         if (previous->function == CF_SCHANGE)
  85             m0 = (3 * previous->spline.a + 2 * previous->spline.b + previous->spline.c) * state_frames / previous_frames ;
  86         else
  87             if (previous->function == CF_CHANGE || previous->function == CF_SWEEP)
  88                 m0 = state_tangent(start, previous->frame, T_BEFORE) * state_frames;
  89             else
  90                 m0 = (state->value - previous->value);
  91         if (newState->function == CF_SCHANGE)
  92             m1 = /*0.5 * */(newState->value - previous->value) * state_frames / (new_frames + state_frames);
  93         else
  94             if (newState->function == CF_CHANGE || newState->function == CF_SWEEP)
  95                 m1 = state_tangent(previous, state->frame, T_AFTER) * state_frames;
  96             else
  97                 m1 = (newState->value - state->value);
  98         state->spline.a = 2 * p0 + m0 - 2 * p1 + m1;
  99         state->spline.b = -3 * p0 - 2 * m0 + 3 * p1 - m1;
 100         state->spline.c = m0;
 101         state->spline.d = p0;
 102 //      printf("p0: %f, p1: %f, m0: %f, m1: %f.\n", p0, p1, m0, m1);
 103 //      printf("a: %f, b: %f, c: %f, d: %f.\n", state->spline.a, state->spline.b, state->spline.c, state->spline.d);
 104     }
 105     if (newState->function == CF_SCHANGE)
 106     {
 107         p0 = state->value;
 108         p1 = newState->value;
 109         if (state->function == CF_SCHANGE)
 110             m0 = m1;
 111         else
 112             if (state->function == CF_CHANGE || state->function == CF_SWEEP)
 113                 m0 = state_tangent(start, state->frame, T_BEFORE) * new_frames;
 114             else
 115                 m0 = (newState->value - state->value);
 116         m1 = (newState->value - state->value);
 117         newState->spline.a = 2 * p0 + m0 - 2 * p1 + m1;
 118         newState->spline.b = -3 * p0 - 2 * m0 + 3 * p1 - m1;
 119         newState->spline.c = m0;
 120         newState->spline.d = p0;
 121 //      printf("p0: %f, p1: %f, m0: %f, m1: %f.\n", p0, p1, m0, m1);
 122 //      printf("a: %f, b: %f, c: %f, d: %f.\n", newState->spline.a, newState->spline.b, newState->spline.c, newState->spline.d);
 123     }
 124     }
 125
 126 void state_insert(state_t* state, state_t* newState)
 127 {
 128     while (state->next && state->next->frame < newState->frame)
 129         state = state->next;
 130     newState->next = state->next;
 131     state->next = newState;
 132     // if this is going to be used to insert CF_SCHANGE states it will have to be extended
 133     // as in state_append above. I know this is not necessary right now, so I'll be lazy.
 134 }
 135
 136 float calculateSpline(state_t* modification, float fraction)
 137 {
 138     spline_t s = modification->spline;
 139     return (((s.a * fraction) + s.b) * fraction + s.c) * fraction + s.d;
 140 }
 141
 142 float interpolateScalar(float p1, float p2, float fraction, interpolation_t* inter)
 143 {
 144         if (!inter)
 145                 return linear(fraction, p1, p2 - p1);
 146         switch (inter->function)
 147         {
 148                 case IF_LINEAR: return linear(fraction, p1, p2 - p1);
 149         case IF_QUAD_IN: return quadIn(fraction, p1, p2 - p1, inter->slope);
 150         case IF_QUAD_OUT: return quadOut(fraction, p1, p2 - p1, inter->slope);
 151         case IF_QUAD_IN_OUT: return quadInOut(fraction, p1, p2 - p1, inter->slope);
 152         case IF_CUBIC_IN: return cubicIn(fraction, p1, p2 - p1, inter->slope);
 153         case IF_CUBIC_OUT: return cubicOut(fraction, p1, p2 - p1, inter->slope);
 154         case IF_CUBIC_IN_OUT: return cubicInOut(fraction, p1, p2 - p1, inter->slope);
 155         case IF_QUART_IN: return quartIn(fraction, p1, p2 - p1, inter->slope);
 156         case IF_QUART_OUT: return quartOut(fraction, p1, p2 - p1, inter->slope);
 157         case IF_QUART_IN_OUT: return quartInOut(fraction, p1, p2 - p1, inter->slope);
 158         case IF_QUINT_IN: return quintIn(fraction, p1, p2 - p1, inter->slope);
 159         case IF_QUINT_OUT: return quintOut(fraction, p1, p2 - p1, inter->slope);
 160         case IF_QUINT_IN_OUT: return quintInOut(fraction, p1, p2 - p1, inter->slope);
 161         case IF_CIRCLE_IN: return circleIn(fraction, p1, p2 - p1, inter->slope);
 162         case IF_CIRCLE_OUT: return circleOut(fraction, p1, p2 - p1, inter->slope);
 163         case IF_CIRCLE_IN_OUT: return circleInOut(fraction, p1, p2 - p1, inter->slope);
 164                 case IF_EXPONENTIAL_IN: return exponentialIn(fraction, p1, p2 - p1);
 165                 case IF_EXPONENTIAL_OUT: return exponentialOut(fraction, p1, p2 - p1);
 166                 case IF_EXPONENTIAL_IN_OUT: return exponentialInOut(fraction, p1, p2 - p1);
 167                 case IF_SINE_IN: return sineIn(fraction, p1, p2 - p1);
 168                 case IF_SINE_OUT: return sineOut(fraction, p1, p2 - p1);
 169                 case IF_SINE_IN_OUT: return sineInOut(fraction, p1, p2 - p1);
 170                 case IF_ELASTIC_IN: return elasticIn(fraction, p1, p2 - p1, inter->amplitude, inter->bounces, inter->damping);
 171                 case IF_ELASTIC_OUT: return elasticOut(fraction, p1, p2 - p1, inter->amplitude, inter->bounces, inter->damping);
 172                 case IF_ELASTIC_IN_OUT: return elasticInOut(fraction, p1, p2 - p1, inter->amplitude, inter->bounces, inter->damping);
 173                 case IF_BACK_IN: return backIn(fraction, p1, p2 - p1, inter->speed);
 174                 case IF_BACK_OUT: return backOut(fraction, p1, p2 - p1, inter->speed);
 175                 case IF_BACK_IN_OUT: return backInOut(fraction, p1, p2 - p1, inter->speed);
 176                 case IF_BOUNCE_IN: return bounceIn(fraction, p1, p2 - p1, inter->bounces, inter->growth, inter->damping);
 177                 case IF_BOUNCE_OUT: return bounceOut(fraction, p1, p2 - p1, inter->bounces, inter->growth, inter->damping);
 178                 case IF_BOUNCE_IN_OUT: return bounceInOut(fraction, p1, p2 - p1, inter->bounces, inter->growth, inter->damping);
 179                 case IF_FAST_BOUNCE_IN: return fastBounceIn(fraction, p1, p2 - p1, inter->bounces, inter->growth, inter->damping);
 180                 case IF_FAST_BOUNCE_OUT: return fastBounceOut(fraction, p1, p2 - p1, inter->bounces, inter->growth, inter->damping);
 181                 case IF_FAST_BOUNCE_IN_OUT: return fastBounceInOut(fraction, p1, p2 - p1, inter->bounces, inter->growth, inter->damping);
 182                 default: return linear(fraction, p1, p2 - p1);
 183         }
 184 }
 185
 186 float calculateSweep(state_t* modification, float fraction)
 187 {
 188     arc_t* a = &(modification->arc);
 189     float angle = a->angle + fraction * a->delta_angle;
 190     if (a->X)
 191         return a->cX + a->r * cos(angle);
 192     else
 193         return a->cY + a->r * sin(angle);
 194
 195 }
 196
 197 int state_differs(state_t* modification, U16 frame)
 198 {
 199     state_t* previous = modification;
 200     while (modification && modification->frame < frame)
 201         {
 202         previous = modification;
 203         modification = modification->next;
 204     }
 205     if (!modification)
 206         return 0;
 207     if (modification->frame == frame)
 208         return 1;
 209     return (modification->function != CF_JUMP);
 210         }
 211
 212 float state_tangent(state_t* modification, U16 frame, int tangent)
 213 {
 214     float deltaFrame = 0.1;
 215     switch (tangent)
 216 {
 217         case T_BEFORE:
 218             return (state_value(modification, frame) - state_value(modification, frame - deltaFrame)) / deltaFrame;
 219         case T_AFTER:
 220             return (state_value(modification, frame + deltaFrame) - state_value(modification, frame)) / deltaFrame;
 221         default:
 222             return (state_value(modification, frame + deltaFrame) - state_value(modification, frame - deltaFrame)) / (2 * deltaFrame);
 223     }
 224 }
 225
 226 float state_value(state_t* modification, float frame)
 227 {
 228     state_t* previous = modification;
 229     while (modification && modification->frame < frame)
 230     {
 231         previous = modification;
 232         modification = modification->next;
 233     }
 234     if (!modification)
 235                 return previous->value;
 236     if (modification->frame == frame)
 237         {
 238                 do
 239                 {
 240             previous = modification;
 241             modification = modification->next;
 242                 }
 243         while (modification && modification->frame == frame);
 244         return previous->value;
 245         }
 246     switch (modification->function)
 247         {
 248                 case CF_PUT:
 249             return modification->value;
 250                 case CF_CHANGE:
 251                 {
 252             float fraction = (frame - previous->frame) / (float)(modification->frame - previous->frame);
 253             return interpolateScalar(previous->value, modification->value, fraction, modification->interpolation);
 254         }
 255         case CF_SCHANGE:
 256         {
 257             float fraction = (frame - previous->frame) / (float)(modification->frame - previous->frame);
 258             fraction = interpolateScalar(0, 1, fraction, modification->interpolation);
 259             return calculateSpline(modification, fraction);
 260                 }
 261         case CF_SWEEP:
 262         {
 263             float fraction = (frame - previous->frame) / (float)(modification->frame - previous->frame);
 264             fraction = interpolateScalar(0, 1, fraction, modification->interpolation);
 265             return calculateSweep(modification, fraction);
 266         }
 267                 case CF_JUMP:
 268                         return previous->value;
 269                 default:
 270                         return 0;
 271         }
 272 }
 273
 274 filterState_t* filterState_new(U16 frame, int function, FILTERLIST* value, interpolation_t* inter)
 275 {
 276     filterState_t* newChange = (filterState_t*)malloc(sizeof(filterState_t));
 277     filterState_init(newChange);
 278         newChange->frame = frame;
 279         newChange->function = function;
 280         newChange->value = value;
 281         newChange->interpolation = inter;
 282         return newChange;
 283 }
 284
 285 void filterState_free(filterState_t *change)
 286 {
 287         if (change->next)
 288         filterState_free(change->next);
 289     free(change->value);
 290         free(change);
 291 }
 292
 293 void filterState_init(filterState_t* change)
 294 {
 295     memset(change, 0, sizeof(filterState_t));
 296 }
 297
 298 void filterState_append(filterState_t* first, filterState_t* newChange)
 299 {
 300         while (first->next)
 301                 first = first->next;
 302     if (!first->value || !newChange->value)
 303         first->next = newChange;
 304     else
 305     {
 306         int i, mergedCount = 0;
 307         int common = first->value->num < newChange->value->num ? first->value->num : newChange->value->num;
 308         for (i = 0; i < common; i++)
 309         {
 310             mergedCount++;
 311             if (newChange->value->filter[i]->type != first->value->filter[i]->type)
 312                 mergedCount++;
 313         }
 314         mergedCount = mergedCount + first->value->num - common + newChange->value->num - common;
 315         if (mergedCount > 8)
 316         {
 317             char* list1;
 318             char* list2;
 319             char* newList;
 320             list1 = (char*)malloc(1);
 321             *list1 = '\0';
 322             for (i = 0; i < first->value->num; i++)
 323             {
 324                 newList = (char*)malloc(strlen(list1) + strlen(filtername[first->value->filter[i]->type]) + 2);
 325                 newList = strcat(strcat(list1, "+"), filtername[first->value->filter[i]->type]);
 326                 free(list1);
 327                 list1 = newList;
 328             }
 329             list2 = (char*)malloc(1);
 330             *list2 = '\0';
 331             for (i = 0; i < newChange->value->num; i++)
 332             {
 333                 newList = (char*)malloc(strlen(list1) + strlen(filtername[newChange->value->filter[i]->type]) + 2);
 334                 newList = strcat(strcat(list2, "+"), filtername[newChange->value->filter[i]->type]);
 335                 free(list2);
 336                 list2 = newList;
 337             }
 338             syntaxerror("filterlists %s and %s cannot be interpolated.", list1, list2);
 339         }
 340         first->next = newChange;
 341     }
 342 }
 343
 344 RGBA interpolateColor(RGBA c1, RGBA c2, float ratio, interpolation_t* inter)
 345 {
 346     RGBA c;
 347     c.r = interpolateScalar(c1.r, c2.r, ratio, inter);
 348     c.g = interpolateScalar(c1.g, c2.g, ratio, inter);
 349     c.b = interpolateScalar(c1.b, c2.b, ratio, inter);
 350     c.a = interpolateScalar(c1.a, c2.a, ratio, inter);
 351     return c;
 352 }
 353
 354 GRADIENT* interpolateNodes(GRADIENT* g1, GRADIENT* g2, float fraction, interpolation_t* inter)
 355 {
 356     if (g1->num != g2->num)
 357         syntaxerror("Internal error: gradients are not equal in size");
 358
 359     int i;
 360     GRADIENT* g = (GRADIENT*) malloc(sizeof(GRADIENT));
 361     g->ratios = rfx_calloc(16*sizeof(U8));
 362     g->rgba = rfx_calloc(16*sizeof(RGBA));
 363     g->num = g1->num;
 364     for (i = 0; i < g->num; i++)
 365     {
 366         g->ratios[i] = interpolateScalar(g1->ratios[i], g2->ratios[i], fraction, inter);
 367         g->rgba[i] = interpolateColor(g1->rgba[i], g2->rgba[i], fraction, inter);
 368     }
 369     return g;
 370 }
 371
 372 void copyGradient(GRADIENT* dest, GRADIENT* source)
 373 {
 374     dest->num = source->num;
 375     memcpy(dest->ratios, source->ratios, source->num * sizeof(U8));
 376     memcpy(dest->rgba, source->rgba, source->num * sizeof(RGBA));
 377 }
 378
 379 void insertNode(GRADIENT* g, int pos)
 380 {
 381     memmove(&g->ratios[pos + 1], &g->ratios[pos], (g->num - pos) * sizeof(U8));
 382     memmove(&g->rgba[pos + 1], &g->rgba[pos], (g->num - pos) * sizeof(RGBA));
 383     if (pos == 0)
 384     {
 385         g->ratios[0] = g->ratios[1] / 2;
 386         g->rgba[0] = g->rgba[1];
 387     }
 388     else
 389         if (pos == g->num)
 390         {
 391             g->ratios[pos] = (255 + g->ratios[g->num - 1]) / 2;
 392             g->rgba[pos] = g->rgba[pos - 1];
 393         }
 394         else
 395         {
 396             g->ratios[pos] = (g->ratios[pos - 1] + g->ratios[pos + 1]) / 2;
 397             g->rgba[pos] = interpolateColor(g->rgba[pos - 1], g->rgba[pos + 1], 0.5, 0);
 398         }
 399     g->num++;
 400 }
 401
 402 void insertOptimalNode(GRADIENT* g)
 403 {
 404     int i, next_gap;
 405     int pos = 0;
 406     int gap = g->ratios[0];
 407     for (i = 0; i < g->num - 1; i++)
 408     {
 409         next_gap = g->ratios[i + 1] - g->ratios[i];
 410         if (next_gap > gap)
 411         {
 412             gap = next_gap;
 413             pos = i + 1;
 414         }
 415     }
 416     next_gap = 255 - g->ratios[g->num -1];
 417     if (next_gap > gap)
 418         pos = g->num;
 419     insertNode(g, pos);
 420 }
 421
 422 void growGradient(GRADIENT* start, int size)
 423 {
 424     while (start->num < size)
 425         insertOptimalNode(start);
 426 }
 427
 428 GRADIENT* interpolateGradient(GRADIENT* g1, GRADIENT* g2, float fraction, interpolation_t* inter)
 429 {
 430     int i;
 431     GRADIENT g;
 432     g.ratios = rfx_calloc(16*sizeof(U8));
 433     g.rgba = rfx_calloc(16*sizeof(RGBA));
 434
 435     if (g1->num > g2->num)
 436     {
 437         copyGradient(&g, g2);
 438         growGradient(&g, g1->num);
 439         GRADIENT* result = interpolateNodes(g1, &g, fraction, inter);
 440         rfx_free(g.rgba);
 441         rfx_free(g.ratios);
 442         return result;
 443     }
 444     else
 445         if (g1->num < g2->num)
 446         {
 447             copyGradient(&g, g1);
 448             growGradient(&g, g2->num);
 449             GRADIENT* result = interpolateNodes(&g, g2, fraction, inter);
 450             rfx_free(g.rgba);
 451             rfx_free(g.ratios);
 452             return result;
 453         }
 454         else
 455             return interpolateNodes(g1, g2, fraction, inter);
 456 }
 457
 458 FILTER* copyFilter(FILTER* original)
 459 {
 460     if (!original)
 461         return original;
 462     FILTER* copy = swf_NewFilter(original->type);
 463     switch (original->type)
 464     {
 465         case FILTERTYPE_BLUR:
 466             memcpy(copy, original, sizeof(FILTER_BLUR));
 467             break;
 468         case FILTERTYPE_GRADIENTGLOW:
 469         {
 470             memcpy(copy, original, sizeof(FILTER_GRADIENTGLOW));
 471             FILTER_GRADIENTGLOW* ggcopy = (FILTER_GRADIENTGLOW*)copy;
 472             ggcopy->gradient = (GRADIENT*)malloc(sizeof(GRADIENT));
 473             ggcopy->gradient->ratios = (U8*)malloc(16 * sizeof(U8));
 474             ggcopy->gradient->rgba = (RGBA*)malloc(16 * sizeof(RGBA));
 475             copyGradient(ggcopy->gradient, ((FILTER_GRADIENTGLOW*)original)->gradient);
 476         }
 477             break;
 478         case FILTERTYPE_DROPSHADOW:
 479             memcpy(copy, original, sizeof(FILTER_DROPSHADOW));
 480             break;
 481         case FILTERTYPE_BEVEL:
 482             memcpy(copy, original, sizeof(FILTER_BEVEL));
 483             break;
 484         default: syntaxerror("Internal error: unsupported filterype, cannot copy");
 485     }
 486     return copy;
 487 }
 488
 489 FILTER* interpolateBlur(FILTER* filter1, FILTER* filter2, float ratio, interpolation_t* inter)
 490         {
 491                 FILTER_BLUR*f1 = (FILTER_BLUR*)filter1;
 492                 FILTER_BLUR*f2 = (FILTER_BLUR*)filter2;
 493     if (!f1)
 494         f1 = noBlur;
 495     if (!f2)
 496         f2 = noBlur;
 497     if(f1->blurx == f2->blurx && f1->blury == f2->blury)
 498         return copyFilter(filter1);
 499                 FILTER_BLUR*f = (FILTER_BLUR*)swf_NewFilter(FILTERTYPE_BLUR);
 500     f->blurx= interpolateScalar(f1->blurx, (f2->blurx), ratio, inter);
 501     f->blury= interpolateScalar(f1->blury, (f2->blury), ratio, inter);
 502     f->passes= interpolateScalar(f1->passes, (f2->passes), ratio, inter);
 503                 return (FILTER*)f;
 504                 }
 505
 506 void matchDropshadowFlags(FILTER_DROPSHADOW* unset, FILTER_DROPSHADOW* target)
 507 {
 508     unset->innershadow = target->innershadow;
 509     unset->knockout = target->knockout;
 510     unset->composite = target->composite;
 511 }
 512
 513 FILTER* interpolateDropshadow(FILTER* filter1,FILTER* filter2, float ratio, interpolation_t* inter)
 514                 {
 515                         FILTER_DROPSHADOW*f1 = (FILTER_DROPSHADOW*)filter1;
 516                         FILTER_DROPSHADOW*f2 = (FILTER_DROPSHADOW*)filter2;
 517     if (!f1)
 518         f1 = noDropshadow;
 519     if (!f2)
 520         f2 = noDropshadow;
 521     if(!memcmp(&f1->color,&f2->color,sizeof(RGBA)) && f1->strength == f2->strength &&
 522                                 f1->blurx == f2->blurx && f1->blury == f2->blury &&
 523                                 f1->angle == f2->angle && f1->distance == f2->distance)
 524                 return copyFilter(filter1);
 525                         FILTER_DROPSHADOW*f = (FILTER_DROPSHADOW*)swf_NewFilter(FILTERTYPE_DROPSHADOW);
 526                         memcpy(f, f1, sizeof(FILTER_DROPSHADOW));
 527                         f->color = interpolateColor(f1->color, f2->color, ratio, inter);
 528     f->blurx= interpolateScalar(f1->blurx, (f2->blurx), ratio, inter);
 529     f->blury= interpolateScalar(f1->blury, (f2->blury), ratio, inter);
 530     f->passes= interpolateScalar(f1->passes, (f2->passes), ratio, inter);
 531     f->angle= interpolateScalar(f1->angle, (f2->angle), ratio, inter);
 532     f->distance= interpolateScalar(f1->distance, (f2->distance), ratio, inter);
 533     f->strength= interpolateScalar(f1->strength, (f2->strength), ratio, inter);
 534     if (f1 == noDropshadow)
 535     {
 536         if (f2 != noDropshadow)
 537             matchDropshadowFlags(f, f2);
 538                 }
 539                 else
 540         if (f2 == noDropshadow)
 541             matchDropshadowFlags(f, f1);
 542         else
 543             if (ratio > 0.5)
 544                 matchDropshadowFlags(f, f2);
 545             else
 546                 matchDropshadowFlags(f, f1);
 547     return (FILTER*)f;
 548 }
 549
 550 void matchBevelFlags(FILTER_BEVEL* unset, FILTER_BEVEL* target)
 551 {
 552     unset->innershadow = target->innershadow;
 553     unset->knockout = target->knockout;
 554     unset->composite = target->composite;
 555     unset->ontop = target->ontop;
 556 }
 557
 558 FILTER* interpolateBevel(FILTER* filter1,FILTER* filter2, float ratio, interpolation_t* inter)
 559                         {
 560                                 FILTER_BEVEL*f1 = (FILTER_BEVEL*)filter1;
 561                                 FILTER_BEVEL*f2 = (FILTER_BEVEL*)filter2;
 562     if (!f1)
 563         f1 = noBevel;
 564     if (!f2)
 565         f2 = noBevel;
 566     if(!memcmp(&f1->shadow,&f2->shadow,sizeof(RGBA)) &&
 567                                         !memcmp(&f1->highlight,&f2->highlight,sizeof(RGBA)) &&
 568                                         f1->blurx == f2->blurx && f1->blury == f2->blury && f1->angle == f2->angle && f1->strength == f2->strength && f1->distance == f2->distance)
 569                 return copyFilter(filter1);
 570                                 FILTER_BEVEL*f = (FILTER_BEVEL*)swf_NewFilter(FILTERTYPE_BEVEL);
 571                                 memcpy(f, f1, sizeof(FILTER_BEVEL));
 572                                 f->shadow = interpolateColor(f1->shadow, f2->shadow, ratio, inter);
 573                                 f->highlight = interpolateColor(f1->highlight, f2->highlight, ratio, inter);
 574     f->blurx= interpolateScalar(f1->blurx, (f2->blurx), ratio, inter);
 575     f->blury= interpolateScalar(f1->blury, (f2->blury), ratio, inter);
 576     f->passes= interpolateScalar(f1->passes, (f2->passes), ratio, inter);
 577     f->angle= interpolateScalar(f1->angle, (f2->angle), ratio, inter);
 578     f->distance= interpolateScalar(f1->distance, (f2->distance), ratio, inter);
 579     f->strength= interpolateScalar(f1->strength, (f2->strength), ratio, inter);
 580     if (f1 == noBevel)
 581     {
 582         if (f2 != noBevel)
 583             matchBevelFlags(f, f2);
 584     }
 585     else
 586         if (f2 == noBevel)
 587             matchBevelFlags(f, f1);
 588         else
 589             if (ratio > 0.5)
 590                 matchBevelFlags(f, f2);
 591             else
 592                 matchBevelFlags(f, f1);
 593                                 return (FILTER*)f;
 594 }
 595
 596 void matchGradientGlowFlags(FILTER_GRADIENTGLOW* unset, FILTER_GRADIENTGLOW* target)
 597 {
 598     unset->innershadow = target->innershadow;
 599     unset->knockout = target->knockout;
 600     unset->composite = target->composite;
 601     unset->ontop = target->ontop;
 602 }
 603
 604 FILTER* interpolateGradientGlow(FILTER* filter1,FILTER* filter2, float ratio, interpolation_t* inter)
 605 {
 606     FILTER_GRADIENTGLOW*f1 = (FILTER_GRADIENTGLOW*)filter1;
 607     FILTER_GRADIENTGLOW*f2 = (FILTER_GRADIENTGLOW*)filter2;
 608     if (!f1)
 609         f1 = noGradientGlow;
 610     if (!f2)
 611         f2 = noGradientGlow;
 612     if(f1->gradient->num == f2->gradient->num &&
 613                 !memcmp(&f1->gradient->ratios,&f2->gradient->ratios,f1->gradient->num * sizeof(U8)) &&
 614                 !memcmp(&f1->gradient->rgba,&f2->gradient->rgba,f1->gradient->num * sizeof(RGBA)) &&
 615                 f1->blurx == f2->blurx && f1->blury == f2->blury && f1->angle == f2->angle && f1->strength == f2->strength && f1->distance == f2->distance)
 616                 return copyFilter(filter1);
 617         FILTER_GRADIENTGLOW*f = (FILTER_GRADIENTGLOW*)swf_NewFilter(FILTERTYPE_GRADIENTGLOW);
 618     memcpy(f, f1, sizeof(FILTER_GRADIENTGLOW));
 619     f->blurx= interpolateScalar(f1->blurx, (f2->blurx), ratio, inter);
 620     f->blury= interpolateScalar(f1->blury, (f2->blury), ratio, inter);
 621     f->passes= interpolateScalar(f1->passes, (f2->passes), ratio, inter);
 622     f->angle= interpolateScalar(f1->angle, (f2->angle), ratio, inter);
 623     f->distance= interpolateScalar(f1->distance, (f2->distance), ratio, inter);
 624     f->strength= interpolateScalar(f1->strength, (f2->strength), ratio, inter);
 625     f->gradient= interpolateGradient(f1->gradient, f2->gradient, ratio, inter);
 626     if (f1 == noGradientGlow)
 627     {
 628         if (f2 != noGradientGlow)
 629             matchGradientGlowFlags(f, f2);
 630     }
 631     else
 632         if (f2 == noGradientGlow)
 633             matchGradientGlowFlags(f, f1);
 634         else
 635             if (ratio > 0.5)
 636                 matchGradientGlowFlags(f, f2);
 637             else
 638                 matchGradientGlowFlags(f, f1);
 639         return (FILTER*)f;
 640 }
 641
 642 FILTER* interpolateFilter(FILTER* filter1,FILTER* filter2, float ratio, interpolation_t* inter)
 643 {
 644     if(!filter1 && !filter2)
 645         return 0;
 646
 647     int filter_type;
 648     if (!filter1)
 649         filter_type = filter2->type;
 650     else
 651         if (!filter2)
 652             filter_type = filter1->type;
 653         else
 654             if(filter2->type != filter1->type)
 655                 syntaxerror("can't interpolate between %s and %s filters yet", filtername[filter1->type], filtername[filter2->type]);
 656             else
 657                 filter_type = filter1->type;
 658
 659     switch (filter_type)
 660     {
 661         case FILTERTYPE_BLUR:
 662             return interpolateBlur(filter1, filter2, ratio, inter);
 663         case FILTERTYPE_BEVEL:
 664             return interpolateBevel(filter1, filter2, ratio, inter);
 665         case FILTERTYPE_DROPSHADOW:
 666             return interpolateDropshadow(filter1, filter2, ratio, inter);
 667         case FILTERTYPE_GRADIENTGLOW:
 668             return interpolateGradientGlow(filter1, filter2, ratio, inter);
 669         default:
 670             syntaxerror("Filtertype %s not supported yet.\n", filtername[filter1->type]);
 671     }
 672         return 0;
 673 }
 674
 675 FILTERLIST* copyFilterList(FILTERLIST* original)
 676 {
 677         if (!original)
 678                 return original;
 679     int i;
 680     FILTERLIST* copy = (FILTERLIST*)malloc(sizeof(FILTERLIST));
 681     copy->num = original->num;
 682     for (i = 0; i < copy->num; i++)
 683         copy->filter[i] = copyFilter(original->filter[i]);
 684     return copy;
 685 }
 686
 687 FILTER* noFilter(int type)
 688 {
 689     switch (type)
 690         {
 691                 case FILTERTYPE_BLUR:
 692             return (FILTER*)noBlur;
 693                         break;
 694         case FILTERTYPE_BEVEL:
 695             return (FILTER*)noBevel;
 696                         break;
 697                 case FILTERTYPE_DROPSHADOW:
 698             return (FILTER*)noDropshadow;
 699                         break;
 700         case FILTERTYPE_GRADIENTGLOW:
 701             return (FILTER*)noGradientGlow;
 702                         break;
 703         default:
 704             syntaxerror("Internal error: unsupported filtertype, cannot match filterlists");
 705         }
 706     return 0;
 707 }
 708
 709 FILTERLIST* interpolateFilterList(FILTERLIST* list1, FILTERLIST* list2, float ratio, interpolation_t* inter)
 710 {
 711     if (!list1 && !list2)
 712         return list1;
 713     FILTERLIST start, target, dummy;
 714     dummy.num = 0;
 715     if (!list1)
 716         list1 = &dummy;
 717     if (!list2)
 718         list2 = &dummy;
 719     int i, j = 0;
 720     int common = list1->num < list2->num ? list1->num : list2->num;
 721         for (i = 0; i < common; i++)
 722     {
 723         start.filter[j] = list1->filter[i];
 724         if (list2->filter[i]->type == list1->filter[i]->type)
 725         {
 726             target.filter[j] = list2->filter[i];
 727             j++;
 728         }
 729         else
 730         {
 731             target.filter[j] = noFilter(list1->filter[i]->type);
 732             j++;
 733             start.filter[j] = noFilter(list2->filter[i]->type);
 734             target.filter[j] = list2->filter[i];
 735             j++;
 736         }
 737     }
 738     if (list1->num > common)
 739         for (i = common; i < list1->num; i++)
 740         {
 741             start.filter[j] = list1->filter[i];
 742             target.filter[j] = noFilter(list1->filter[i]->type);
 743             j++;
 744         }
 745     if (list2->num > common)
 746         for (i = common; i < list2->num; i++)
 747         {
 748             start.filter[j] = noFilter(list2->filter[i]->type);
 749             target.filter[j] = list2->filter[i];
 750             j++;
 751         }
 752     start.num = j;
 753     target.num = j;
 754     FILTERLIST* mixedList = (FILTERLIST*)malloc(sizeof(FILTERLIST));
 755     mixedList->num = j;
 756     for (i = 0; i < j; i++)
 757         mixedList->filter[i] = interpolateFilter(start.filter[i], target.filter[i], ratio, inter);
 758     return mixedList;
 759 }
 760
 761 int filterState_differs(filterState_t* modification, U16 frame)
 762 {
 763     filterState_t* previous = modification;
 764     while (modification && modification->frame < frame)
 765         {
 766         previous = modification;
 767         modification = modification->next;
 768         }
 769     if (!modification)
 770         return 0;
 771     if (modification->frame == frame)
 772         return 1;
 773     return (modification->function != CF_JUMP);
 774 }
 775
 776 FILTERLIST* filterState_value(filterState_t* modification, U16 frame)
 777 {
 778     filterState_t* previous = modification;
 779     while (modification && modification->frame < frame)
 780     {
 781         previous = modification;
 782         modification = modification->next;
 783     }
 784     if (!modification)
 785         return copyFilterList(previous->value);
 786     if (modification->frame == frame)
 787         {
 788                 do
 789                 {
 790             previous = modification;
 791             modification = modification->next;
 792                 }
 793         while (modification && modification->frame == frame);
 794         return copyFilterList(previous->value);
 795         }
 796     switch (modification->function)
 797         {
 798                 case CF_PUT:
 799             return copyFilterList(modification->value);
 800                 case CF_CHANGE:
 801                 {
 802             float fraction = (frame - previous->frame) / (float)(modification->frame - previous->frame);
 803             return interpolateFilterList(previous->value, modification->value, fraction, modification->interpolation);
 804                 }
 805                 case CF_JUMP:
 806             return copyFilterList(previous->value);
 807                 default:
 808                         return 0;
 809         }
 810 }
 811
 812 history_t* history_new()
 813 {
 814         history_t* newHistory = (history_t*)malloc(sizeof(history_t));
 815         history_init(newHistory);
 816         return newHistory;
 817 }
 818
 819 void history_free(history_t* past)
 820 {
 821     state_free(dict_lookup(past->states, "x"));
 822     state_free(dict_lookup(past->states, "y"));
 823     state_free(dict_lookup(past->states, "scalex"));
 824     state_free(dict_lookup(past->states, "scaley"));
 825     state_free(dict_lookup(past->states, "cxform.r0"));
 826     state_free(dict_lookup(past->states, "cxform.g0"));
 827     state_free(dict_lookup(past->states, "cxform.b0"));
 828     state_free(dict_lookup(past->states, "cxform.a0"));
 829     state_free(dict_lookup(past->states, "cxform.r1"));
 830     state_free(dict_lookup(past->states, "cxform.g1"));
 831     state_free(dict_lookup(past->states, "cxform.b1"));
 832     state_free(dict_lookup(past->states, "cxform.a1"));
 833     state_free(dict_lookup(past->states, "rotate"));
 834     state_free(dict_lookup(past->states, "shear"));
 835     state_free(dict_lookup(past->states, "pivot.x"));
 836     state_free(dict_lookup(past->states, "pivot.y"));
 837     state_free(dict_lookup(past->states, "pin.x"));
 838     state_free(dict_lookup(past->states, "pin.y"));
 839     state_free(dict_lookup(past->states, "blendmode"));
 840     state_free(dict_lookup(past->states, "flags"));
 841     filterState_free(dict_lookup(past->states, "filter"));
 842     dict_destroy(past->states);
 843     free(past);
 844 }
 845
 846 void history_init(history_t* past)
 847 {
 848     past->states = (dict_t*)malloc(sizeof(dict_t));
 849     dict_init(past->states, 16);
 850 }
 851
 852 void history_begin(history_t* past, char* parameter, U16 frame, TAG* tag, float value)
 853 {
 854     state_t* first = state_new(frame, CF_PUT, value, 0);
 855         past->firstTag = tag;
 856         past->firstFrame = frame;
 857     dict_put2(past->states, parameter, first);
 858 }
 859
 860 void history_beginFilter(history_t* past, U16 frame, TAG* tag, FILTERLIST* value)
 861 {
 862     filterState_t* first = filterState_new(frame, CF_PUT, value, 0);
 863         past->firstTag = tag;
 864         past->firstFrame = frame;
 865     dict_put2(past->states, "filter", first);
 866 }
 867
 868 void history_remember(history_t* past, char* parameter, U16 frame, int function, float value, interpolation_t* inter)
 869 {
 870     past->lastFrame = frame;
 871     state_t* state = dict_lookup(past->states, parameter);
 872     if (state) //should always be true
 873     {
 874         state_t* next = state_new(frame, function, value, inter);
 875         state_append(state, next);
 876     }
 877     else
 878         syntaxerror("Internal error: changing parameter %s, which is unknown for the instance.", parameter);
 879 }
 880
 881 static float getAngle(float dX, float dY)
 882 {
 883     float radius = sqrt(dX * dX + dY * dY);
 884     if (radius == 0)
 885         return 0.0;
 886     if (dX >= 0)
 887         if (dY > 0)
 888             return acos(dX / radius);
 889         else
 890             return 2 * M_PI - acos(dX / radius);
 891     else
 892         if (dY > 0)
 893             return M_PI - acos(-dX / radius);
 894         else
 895             return M_PI + acos(-dX / radius);
 896 }
 897
 898 static float getDeltaAngle(float angle1, float angle2, int clockwise)
 899         {
 900             if (!clockwise)
 901             {
 902                 if (angle1 > angle2)
 903                     return angle2 - angle1;
 904                 else
 905                     return angle2 - angle1 - 2 * M_PI;
 906             }
 907             else
 908             {
 909                 if (angle1 > angle2)
 910                     return 2 * M_PI - angle1 + angle2;
 911                 else
 912                     return angle2 - angle1;
 913         }
 914 }
 915
 916 void history_rememberSweep(history_t* past, U16 frame, float x, float y, float r, int clockwise, int short_arc, interpolation_t* inter)
 917 {
 918     float lastX, lastY, dX, dY;
 919     U16 lastFrame;
 920
 921     past->lastFrame = frame;
 922     state_t* change = dict_lookup(past->states, "x");
 923     if (change) //should always be true
 924     {
 925         while (change->next)
 926             change = change->next;
 927         lastFrame = change->frame;
 928         lastX = change->value;
 929         change = dict_lookup(past->states, "y");
 930         if (change) //should always be true
 931         {
 932             while (change->next)
 933                 change = change->next;
 934             lastY = change->value;
 935             dX = x - lastX;
 936             dY = y - lastY;
 937             if (dX == 0 && dY == 0)
 938                 syntaxerror("sweep not possible: startpoint and endpoint must not be equal");
 939             if ((dX) * (dX) + (dY) * (dY) > 4 * r * r)
 940                 syntaxerror("sweep not possible: radius is to small");
 941             if (change->frame > lastFrame)
 942             {
 943                 lastFrame = change->frame;
 944                 history_remember(past, "x", lastFrame, CF_JUMP, lastX, 0);
 945             }
 946             else
 947                 if (change->frame < lastFrame)
 948                     history_remember(past, "y", lastFrame, CF_JUMP, lastY, 0);
 949             float c1X, c1Y, c2X, c2Y;
 950             if (dX == 0) //vertical
 951             {
 952                 c1Y = c2Y = (lastY + y) / 2;
 953                 c1X = x + sqrt(r * r - (c1Y - y) * (c1Y - y));
 954                 c2X = 2 * x -c1X;
 955             }
 956             else
 957                 if (dY == 0) //horizontal
 958                 {
 959                     c1X = c2X = (lastX + x) / 2;
 960                     c1Y = y +sqrt(r * r - (c1X - x) * (c1X - x));
 961                     c2Y = 2 * y -c1Y;
 962                 }
 963                 else
 964                 {
 965                     c1X = sqrt((r * r - (dX * dX + dY * dY) / 4) / (1 + dX * dX / dY / dY));
 966                     c2X = -c1X;
 967                     c1Y = -dX / dY * c1X;
 968                     c2Y = -c1Y;
 969                     c1X += (x + lastX) / 2;
 970                     c2X += (x + lastX) / 2;
 971                     c1Y += (y + lastY) / 2;
 972                     c2Y += (y + lastY) / 2;
 973                 }
 974             float angle1, angle2, delta_angle, centerX, centerY;
 975             angle1 = getAngle(lastX - c1X, lastY - c1Y);
 976             angle2 = getAngle(x - c1X, y - c1Y);
 977             delta_angle = getDeltaAngle(angle1, angle2, clockwise);
 978             if ((short_arc && fabs(delta_angle) <= M_PI) || (! short_arc && fabs(delta_angle) >= M_PI))
 979             {
 980                 centerX = c1X;
 981                 centerY = c1Y;
 982             }
 983             else
 984             {
 985                 angle1 = getAngle(lastX - c2X, lastY - c2Y);
 986                 angle2 = getAngle(x - c2X, y - c2Y);
 987                 delta_angle = getDeltaAngle(angle1, angle2, clockwise);
 988                 centerX = c2X;
 989                 centerY = c2Y;
 990             }
 991             change = dict_lookup(past->states, "x");
 992             state_t* nextX = state_new(frame, CF_SWEEP, x, inter);
 993             nextX->arc.r = r;
 994             nextX->arc.angle = angle1;
 995             nextX->arc.delta_angle = delta_angle;
 996             nextX->arc.cX = centerX;
 997             nextX->arc.cY = centerY;
 998             nextX->arc.X = 1;
 999             state_append(change, nextX);
1000             change = dict_lookup(past->states, "y");
1001             state_t* nextY = state_new(frame, CF_SWEEP, y, inter);
1002             nextY->arc.r = r;
1003             nextY->arc.angle = angle1;
1004             nextY->arc.delta_angle = delta_angle;
1005             nextY->arc.cX = centerX;
1006             nextY->arc.cY = centerY;
1007             nextY->arc.X = 0;
1008             state_append(change, nextY);
1009         }
1010         else
1011             syntaxerror("Internal error: changing parameter y in sweep, which is unknown for the instance.");
1012     }
1013     else
1014         syntaxerror("Internal error: changing parameter x in sweep, which is unknown for the instance.");
1015 }
1016
1017 void history_rememberFilter(history_t* past, U16 frame, int function, FILTERLIST* value, interpolation_t* inter)
1018 {
1019     past->lastFrame = frame;
1020     filterState_t* first = dict_lookup(past->states, "filter");
1021         if (first) //should always be true
1022         {
1023         filterState_t* next = filterState_new(frame, function, value, inter);
1024         filterState_append(first, next);
1025     }
1026     else
1027         syntaxerror("Internal error: changing a filter not set for the instance.");
1028 }
1029
1030 void history_processFlags(history_t* past)
1031 // to be called after completely recording this history, before calculating any values.
1032 {
1033     state_t* flagState = dict_lookup(past->states, "flags");
1034     state_t* nextState;
1035     U16 nextFlags, toggledFlags, currentFlags = (U16)flagState->value;
1036     while (flagState->next)
1037     {
1038         nextState = flagState->next;
1039         nextFlags = (U16)nextState->value;
1040         toggledFlags = currentFlags ^ nextFlags;
1041         if (toggledFlags & IF_FIXED_ALIGNMENT)
1042         { // the IF_FIXED_ALIGNMENT bit will change in the next state
1043             if (nextFlags & IF_FIXED_ALIGNMENT)
1044             { // the IF_FIXED_ALIGNMENT bit will be set
1045                 int onFrame = nextState->frame;
1046                 state_t* rotations = dict_lookup(past->states, "rotate");
1047                 nextState->params.instanceAngle = state_value(rotations, onFrame);
1048                 state_t* resetRotate = state_new(onFrame, CF_JUMP, 0, 0);
1049                 state_insert(rotations, resetRotate);
1050                 if (onFrame == past->firstFrame)
1051                     onFrame++;
1052                 state_t *x, *y;
1053                 float dx, dy;
1054                 do
1055                 {
1056                     x = dict_lookup(past->states, "x");
1057                     dx = state_tangent(x, onFrame, T_SYMMETRIC);
1058                     y = dict_lookup(past->states, "y");
1059                     dy = state_tangent(y, onFrame, T_SYMMETRIC);
1060                     onFrame++;
1061                 }
1062                 while (dx == 0 && dy == 0 && onFrame < past->lastFrame);
1063                 if (onFrame == past->lastFrame)
1064                     nextState->params.pathAngle = 0;
1065                 else
1066                     nextState->params.pathAngle = getAngle(dx, dy) / M_PI * 180;
1067             }
1068             else // the IF_FIXED_ALIGNMENT bit will be reset
1069             {
1070                 int offFrame = nextState->frame;
1071                 state_t* rotations = dict_lookup(past->states, "rotate");
1072                 state_t* setRotate = state_new(offFrame, CF_JUMP, flagState->params.instanceAngle + state_value(rotations, offFrame), 0);
1073                 state_insert(rotations, setRotate);
1074             }
1075         }
1076         else // the IF_FIXED_ALIGNMENT bit will not change but some processing may be
1077              // required just the same
1078         {
1079             if (nextFlags & IF_FIXED_ALIGNMENT)
1080             {
1081                 nextState->params.instanceAngle = flagState->params.instanceAngle;
1082                 nextState->params.pathAngle = flagState->params.pathAngle;
1083             }
1084         }
1085 // and so on for all the other bits.
1086         flagState = nextState;
1087         currentFlags = nextFlags;
1088         }
1089 }
1090
1091 int history_change(history_t* past, U16 frame, char* parameter)
1092 {
1093     state_t* first = dict_lookup(past->states, parameter);
1094     if (first)  //should always be true.
1095         return state_differs(first, frame);
1096     syntaxerror("no history found to predict changes for parameter %s.\n", parameter);
1097     return 0;
1098 }
1099
1100 float history_value(history_t* past, U16 frame, char* parameter)
1101 {
1102     state_t* state = dict_lookup(past->states, parameter);
1103     if (state)  //should always be true.
1104         return state_value(state, frame);
1105     syntaxerror("no history found to get a value for parameter %s.\n", parameter);
1106     return 0;
1107 }
1108
1109 float history_rotateValue(history_t* past, U16 frame)
1110 {
1111     state_t* rotations = dict_lookup(past->states, "rotate");
1112     if (rotations)      //should always be true.
1113     {
1114         float angle = state_value(rotations, frame);
1115         state_t* flags = dict_lookup(past->states, "flags");
1116         U16 currentflags = state_value(flags, frame);
1117         if (currentflags & IF_FIXED_ALIGNMENT)
1118         {
1119             flags = state_at(flags, frame);
1120             if (frame == past->firstFrame)
1121                 frame++;
1122             state_t *x, *y;
1123             float dx, dy, pathAngle;
1124             do
1125             {
1126                 x = dict_lookup(past->states, "x");
1127                 dx = state_value(x, frame) - state_value(x, frame - 1);
1128                 y = dict_lookup(past->states, "y");
1129                 dy = state_value(y, frame) - state_value(y, frame - 1);
1130                 frame--;
1131             }
1132             while (dx == 0 && dy == 0 && frame > past->firstFrame);
1133             if (frame == past->firstFrame)
1134                 pathAngle = 0;
1135             else
1136                 pathAngle = getAngle(dx, dy) / M_PI * 180;
1137             return angle + flags->params.instanceAngle + pathAngle - flags->params.pathAngle;
1138         }
1139         else
1140             return angle;
1141     }
1142     syntaxerror("no history found to get a value for parameter rotate.\n");
1143         return 0;
1144 }
1145
1146 int history_changeFilter(history_t* past, U16 frame)
1147 {
1148     filterState_t* first = dict_lookup(past->states, "filter");
1149     if (first)  //should always be true.
1150         return filterState_differs(first, frame);
1151     syntaxerror("no history found to predict changes for parameter filter.\n");
1152     return 0;
1153 }
1154
1155 FILTERLIST* history_filterValue(history_t* past, U16 frame)
1156 {
1157     filterState_t* first = dict_lookup(past->states, "filter");
1158         if (first)      //should always be true.
1159         return filterState_value(first, frame);
1160     syntaxerror("no history found to get a value for parameter filter.\n");
1161         return 0;
1162 }