synfig-core/trunk/src/synfig/gradient.cpp

   1 /* === S Y N F I G ========================================================= */
   2 /*!     \file gradient.cpp
   3 **      \brief Color Gradient Class Member Definitions
   4 **
   5 **      $Id$
   6 **
   7 **      \legal
   8 **      Copyright (c) 2002-2005 Robert B. Quattlebaum Jr., Adrian Bentley
   9 **      Copyright (c) 2007 Chris Moore
  10 **
  11 **      This package is free software; you can redistribute it and/or
  12 **      modify it under the terms of the GNU General Public License as
  13 **      published by the Free Software Foundation; either version 2 of
  14 **      the License, or (at your option) any later version.
  15 **
  16 **      This package is distributed in the hope that it will be useful,
  17 **      but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 **      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  19 **      General Public License for more details.
  20 **      \endlegal
  21 */
  22 /* ========================================================================= */
  23
  24 /* === H E A D E R S ======================================================= */
  25
  26 #ifdef USING_PCH
  27 #       include "pch.h"
  28 #else
  29 #ifdef HAVE_CONFIG_H
  30 #       include <config.h>
  31 #endif
  32
  33 #include "gradient.h"
  34 #include "general.h"
  35 #include <stdexcept>
  36 #include "exception.h"
  37 #include <algorithm>
  38
  39 #include <ETL/misc>
  40 #endif
  41
  42 /* === U S I N G =========================================================== */
  43
  44 using namespace std;
  45 using namespace etl;
  46 using namespace synfig;
  47
  48 /* === M A C R O S ========================================================= */
  49
  50 /* === G L O B A L S ======================================================= */
  51
  52 /* === P R O C E D U R E S ================================================= */
  53
  54 /* === M E T H O D S ======================================================= */
  55
  56 synfig::Gradient::Gradient(const Color &c1, const Color &c2)
  57 {
  58         push_back(CPoint(0.0,c1));
  59         push_back(CPoint(1.0,c2));
  60 }
  61
  62 synfig::Gradient::Gradient(const Color &c1, const Color &c2, const Color &c3)
  63 {
  64         push_back(CPoint(0.0,c1));
  65         push_back(CPoint(0.5,c2));
  66         push_back(CPoint(1.0,c3));
  67 }
  68
  69 // This sort algorithm MUST be stable
  70 // ie: it must not change the order of items with the same value.
  71 // I am using a bubble sort.
  72 // This algorithm will sort a nearly-sorted list at ~O(N), and
  73 // it will sort an inverse sorted list at ~O(N*N).
  74 void
  75 synfig::Gradient::sort()
  76 {
  77         stable_sort(begin(),end());
  78         /*
  79         iterator iter;
  80         iterator iter2,next;
  81
  82         for(iter=begin();iter!=end();iter++)
  83         {
  84                 for(next=iter, iter2=next--;iter2!=begin();iter2=next--)
  85                 {
  86                         if(*iter<*next)
  87                         {
  88                                 //insert(next,*iter);
  89                                 //erase(iter);
  90                                 iter_swap(next,iter);
  91
  92                                 continue;
  93                         }
  94                         else
  95                                 break;
  96                 }
  97         }
  98         */
  99 }
 100
 101 static synfig::ColorAccumulator
 102 supersample_helper(const synfig::Gradient::CPoint &color1, const synfig::Gradient::CPoint &color2, float begin, float end, float &weight)
 103 {
 104         if(color1.pos==color2.pos || color1.pos>=end || color2.pos<=begin)
 105         {
 106                 weight=0;
 107                 return Color::alpha();
 108         }
 109         if(color1.pos>=begin && color2.pos<end)
 110         {
 111                 weight=color2.pos-color1.pos;
 112                 ColorAccumulator ret=Color::blend(color2.color,color1.color, 0.5, Color::BLEND_STRAIGHT).premult_alpha()*weight;
 113                 return ret;
 114         }
 115         if(color1.pos>=begin && color2.pos>=end)
 116         {
 117                 weight=end-color1.pos;
 118                 float pos((end+color1.pos)*0.5);
 119                 float amount((pos-color1.pos)/(color2.pos-color1.pos));
 120                 //if(abs(amount)>1)amount=(amount>0)?1:-1;
 121                 ColorAccumulator ret(Color::blend(color2.color,color1.color, amount, Color::BLEND_STRAIGHT).premult_alpha()*weight);
 122                 return ret;
 123         }
 124         if(color1.pos<begin && color2.pos<end)
 125         {
 126                 weight=color2.pos-begin;
 127                 float pos((begin+color2.pos)*0.5);
 128                 float amount((pos-color1.pos)/(color2.pos-color1.pos));
 129                 //if(abs(amount)>1)amount=(amount>0)?1:-1;
 130                 ColorAccumulator ret(Color::blend(color2.color,color1.color, amount, Color::BLEND_STRAIGHT).premult_alpha()*weight);
 131                 return ret;
 132         }
 133         synfig::error("color1.pos=%f",color1.pos);
 134         synfig::error("color2.pos=%f",color2.pos);
 135         synfig::error("begin=%f",begin);
 136         synfig::error("end=%f",end);
 137
 138         weight=0;
 139         return Color::alpha();
 140
 141 //      assert(0);
 142 }
 143
 144 static void show_gradient(const Gradient::CPointList x)
 145 {
 146         int i = 0;
 147         for (Gradient::const_iterator iter = x.begin(); iter != x.end(); iter++)
 148                 printf("%3d : %.3f %s\n", i++, (*iter).pos, (*iter).color.get_string().c_str());
 149 }
 150
 151 Gradient &
 152 synfig::Gradient::operator+=(const Gradient &rhs)
 153 {
 154         bool print=false;                       // for debugging
 155         if (print) { printf("\nadding lhs:\n"); show_gradient(this->cpoints); printf("\n"); }
 156         if (print) { printf("adding rhs:\n"); show_gradient(rhs.cpoints); printf("\n"); }
 157         CPointList ret;
 158         const_iterator iter1 = begin(), iter2 = rhs.begin(), left_same, right_same;
 159         CPoint left, right;
 160         if (iter1 != end()) left = *iter1;
 161         if (iter2 != rhs.end()) right = *iter2;
 162         int pos1 = 0, pos2 = 0;
 163         CPoint old1, old2;
 164
 165         // if there are cpoints in both gradients run through both until one runs out
 166         if (iter1 != end() && iter2 != rhs.end())
 167                 while(true)
 168                         // if the left one has the first cpoint
 169                         if (left.pos < right.pos)
 170                         {
 171                                 // add on the right gradient's value at this point
 172                                 if (print) printf("using pos %.2f from left %d in loop\n", left.pos, pos1++);
 173                                 ret.push_back(CPoint(left.pos, left.color + rhs(left.pos)));
 174                                 if(++iter1 == end()) break;
 175                                 left=*iter1;
 176                         }
 177                         // if the right one has the first cpoint
 178                         else if (left.pos > right.pos)
 179                         {
 180                                 // add on the left gradient's value at this point
 181                                 if (print) printf("using pos %.2f from right %d in loop\n", right.pos, pos2++);
 182                                 ret.push_back(CPoint(right.pos, right.color + (*this)(right.pos)));
 183                                 if(++iter2 == rhs.end()) break;
 184                                 right=*iter2;
 185                         }
 186                         // they both have a cpoint at the same time
 187                         else
 188                         {
 189                                 int tpos1 = pos1, tpos2 = pos2;
 190                                 // skip past all cpoints at the same position
 191                                 for(left_same = ++iter1; iter1 != end() && (*iter1).pos == left.pos; iter1++, pos1++)
 192                                         if (print) printf("skipping past pos %d in left\n", pos1);
 193                                 for(right_same = ++iter2; iter2 != rhs.end() && (*iter2).pos == right.pos; iter2++, pos2++)
 194                                         if (print) printf("skipping past pos %d in right\n", pos2);
 195
 196                                 // if there is only one cpoint at this position in each gradient,
 197                                 // there's only one corresponding cpoint in the sum
 198                                 if (iter1 == left_same && iter2 == right_same)
 199                                 {
 200                                         if (print) printf("two singles at left %d and right %d\n", pos1++, pos2++);
 201                                         ret.push_back(CPoint(left.pos, left.color + right.color));
 202                                 }
 203                                 // otherwise we sum the first in each, and the last in each
 204                                 else
 205                                 {
 206                                         if (print) printf("[copying %d from left %d and %d from right %d at %.2f]\n", iter1-left_same+1, tpos1, iter2-right_same+1, tpos2, left.pos);
 207                                         // merge the front two cpoints
 208                                         if (print) printf("  copy front from left %d right %d\n", tpos1++, tpos2++);
 209                                         ret.push_back(CPoint(left.pos, left.color + right.color));
 210
 211                                         // merge the middle pairs of points - each middle point merges with its counterpart
 212                                         while(left_same < iter1-1 && right_same < iter2-1)
 213                                         {
 214                                                 old1 = *(left_same++);
 215                                                 old2 = *(right_same++);
 216                                                 if (print) printf("  copy middle from left %d and right %d\n", tpos1++, tpos2++);
 217                                                 ret.push_back(CPoint(old1.pos, old1.color+old2.color));
 218                                         }
 219                                         // if one gradient has more middle points than the other, merge the rest with the last point in the other gradient
 220                                         for(old2 = (*(iter2-1)); left_same < iter1-1; left_same++)
 221                                         {
 222                                                 old1 = *left_same;
 223                                                 if (print) printf("  copy middle from left %d plus end of right\n", tpos1++);
 224                                                 ret.push_back(CPoint(old1.pos, old1.color + old2.color));
 225                                         }
 226                                         for(old1 = (*(iter1-1)); right_same < iter2-1; right_same++)
 227                                         {
 228                                                 old2 = *right_same;
 229                                                 if (print) printf("  copy middle from right %d plus end of left\n", tpos2++);
 230                                                 ret.push_back(CPoint(old2.pos, old1.color + old2.color));
 231                                         }
 232                                         // merge the back two cpoints
 233                                         if (print) printf("  copy end from left %d right %d\n", pos1++, pos2++);
 234                                         ret.push_back(CPoint(left.pos, (*(iter1-1)).color + (*(iter2-1)).color));
 235                                 }
 236                                 // make sure we update 'left' and 'right'
 237                                 if (iter1 != end()) left=*iter1;
 238                                 if (iter2 == rhs.end()) break;
 239                                 right = *iter2;
 240                                 if (iter1 == end()) break;
 241                         }
 242
 243         // one of the gradients has run out of points
 244         // does the left one have points left?
 245         if (iter1 != end())
 246                 while(true)
 247                 {
 248                         if (print) printf("finish end from left %d\n", pos1++);
 249                         ret.push_back(CPoint(left.pos, left.color + rhs(left.pos)));
 250                         if(++iter1 == end()) break;
 251                         left = *iter1;
 252                 }
 253         // the left one was empty, so maybe the right one has points left
 254         else if (iter2 != rhs.end())
 255                 while(true)
 256                 {
 257                         if (print) printf("finish end from right %d\n", pos2++);
 258                         ret.push_back(CPoint(right.pos, right.color + (*this)(right.pos)));
 259                         if(++iter2 == rhs.end()) break;
 260                         right = *iter2;
 261                 }
 262
 263         if (print) { printf("\nsummed ret:\n"); show_gradient(ret); printf("\n"); }
 264         cpoints = ret;
 265         return *this;
 266 }
 267
 268 Gradient &
 269 synfig::Gradient::operator-=(const Gradient &rhs)
 270 {
 271         return (*this)+=(rhs*-1);
 272 }
 273
 274 Gradient &
 275 synfig::Gradient::operator*=(const float    &rhs)
 276 {
 277         if (rhs == 0)
 278                 cpoints.clear();
 279         else
 280                 for (iterator iter = cpoints.begin(); iter!=cpoints.end(); iter++)
 281                         (*iter).color *= rhs;
 282         return *this;
 283 }
 284
 285 Gradient &
 286 synfig::Gradient::operator/=(const float    &rhs)
 287 {
 288         for (iterator iter = cpoints.begin(); iter!=cpoints.end(); iter++)
 289                 (*iter).color /= rhs;
 290         return *this;
 291 }
 292
 293 Color
 294 synfig::Gradient::operator()(const Real &x,float supersample)const
 295 {
 296         if(cpoints.empty())
 297                 return Color(0,0,0,0);
 298         if(supersample<0)
 299                 supersample=-supersample;
 300         if(supersample>2.0)
 301                 supersample=2.0f;
 302
 303         float begin_sample(x-supersample*0.5);
 304         float end_sample(x+supersample*0.5);
 305
 306         if(cpoints.size()==1 || end_sample<=cpoints.front().pos || isnan(x))
 307                 return cpoints.front().color;
 308
 309         if(begin_sample>=cpoints.back().pos)
 310                 return cpoints.back().color;
 311
 312         /*
 313         if(end_sample>=back().pos)
 314                 end_sample=back().pos;
 315
 316         if(begin_sample<=front().pos)
 317                 begin_sample=front().pos;
 318         */
 319
 320         const_iterator iter,next;
 321
 322         /*
 323         //optimize...
 324         Real    left = x-supersample/2, right = x+supersample/2;
 325
 326         if(left < front().pos) left = front().pos;
 327         if(right > back().pos) right = back().pos;
 328
 329         //find using binary search...
 330         const_iterator iterl,iterr;
 331
 332         //the binary search should give us the values BEFORE the point we're looking for...
 333         iterl = binary_find(begin(),end(),left);
 334         iterr = binary_find(iterl,end(),right);
 335
 336         //now integrate over the range of left to right...
 337
 338         if(iterl == iterr)
 339         {
 340                 iterr++; //let's look at the next one shall we :)
 341
 342                 //interpolate neighboring colors
 343                 const Real one = iterr->pos - iterl->pos;
 344                 const Real lambda = (x - iterl->pos)/one;
 345
 346                 //(1-l)iterl + (l)iterr
 347                 return iterl->color.premult_alpha()*(1-lambda) + iterr->color.premult_alpha()*lambda;
 348
 349                 //return Color::blend(iterr->color,iterl->color,lambda,Color::BLEND_STRAIGHT);
 350         }else
 351         {
 352                 //integration madness
 353                 const_iterator i = iterl, ie = iterr+1;
 354                 Real wlast = left;
 355
 356                 ColorAccumulator clast,cwork;
 357                 {
 358                         const Real lambda = (x - iterl->pos)/(iterr->pos - iterl->pos);
 359
 360                         //premultiply because that's the form in which we can combine things...
 361                         clast = iterl->color.premult_alpha()*(1-lambda) + iterr->color.premult_alpha()*lambda;
 362                         //Color::blend((i+1)->color,i->color,(left - i->pos)/((i+1)->pos - i->pos),Color::BLEND_STRAIGHT);
 363                 }
 364
 365                 ColorAccumulator        accum = 0;
 366
 367                 //loop through all the trapezoids and integrate them as we go...
 368                 //      area of trap = (yi + yi1)*(xi1 - xi)
 369                 //      yi = clast, xi = wlast, yi1 = i->color, xi1 = i->pos
 370
 371                 for(;i<=iterr; wlast=i->pos,clast=i->color.premult_alpha(),++i)
 372                 {
 373                         const Real diff = i->pos - wlast;
 374                         if(diff > 0) //only accumulate if there will be area to add
 375                         {
 376                                 cwork = i->color.premult_alpha();
 377                                 accum += (cwork + clast)*diff;
 378                         }
 379                 }
 380
 381                 {
 382                         const_iterator ibef = i-1;
 383                         const Real diff = right - ibef->pos;
 384
 385                         if(diff > 0)
 386                         {
 387                                 const Real lambda = diff/(i->pos - ibef->pos);
 388                                 cwork = ibef->color.premult_alpha()*(1-lambda) + i->color.premult_alpha()*lambda;
 389
 390                                 accum += (cwork + clast)*diff; //can probably optimize this more... but it's not too bad
 391                         }
 392                 }
 393
 394                 accum /= supersample; //should be the total area it was sampled over...
 395                 return accum.demult_alpha();
 396         }*/
 397
 398         next=begin(),iter=next++;
 399
 400         //add for optimization
 401         next = binary_find(begin(),end(),(Real)begin_sample);
 402         iter = next++;
 403
 404         //! As a future optimization, this could be performed faster
 405         //! using a binary search.
 406         for(;iter<end();iter=next++)
 407         {
 408                 if(next==end() || (x>=iter->pos && x<next->pos && iter->pos!=next->pos))
 409                 {
 410                         // If the supersample region falls square in between
 411                         // two CPoints, then we don't have to do anything special.
 412                         if(next!=end() && (!supersample || (iter->pos<=begin_sample && next->pos>=end_sample)))
 413                         {
 414                                 const Real dist(next->pos-iter->pos);
 415                                 const Real pos(x-iter->pos);
 416                                 const Real amount(pos/dist);
 417                                 return Color::blend(next->color,iter->color, amount, Color::BLEND_STRAIGHT);
 418                         }
 419                         // In this case our supersample region extends over one or more
 420                         // CPoints. So, we need to calculate our coverage amount.
 421                         ColorAccumulator pool(Color::alpha());
 422                         float divisor(0.0),weight(0);
 423
 424                         const_iterator iter2,next2;
 425                         iter2=iter;
 426                         if(iter==begin() && iter->pos>x)
 427                         {
 428                                 weight=x-iter->pos;
 429                                 //weight*=iter->color.get_a();
 430                                 pool+=ColorAccumulator(iter->color).premult_alpha()*weight;
 431                                 divisor+=weight;
 432                         }
 433                         else
 434                         {
 435                                 while(iter2->pos>=begin_sample)
 436                                 {
 437                                         if(iter2==begin())
 438                                         {
 439                                                 weight=iter2->pos-(begin_sample);
 440                                                 //weight*=iter2->color.get_a();
 441                                                 pool+=ColorAccumulator(iter2->color).premult_alpha()*weight;
 442                                                 divisor+=weight;
 443                                                 break;
 444                                         }
 445                                         next2=iter2--;
 446                                         pool+=supersample_helper(*iter2, *next2, begin_sample, end_sample, weight);
 447                                         divisor+=weight;
 448                                 }
 449                         }
 450
 451                         next2=iter;
 452                         iter2=next2++;
 453                         while(iter2->pos<=end_sample)
 454                         {
 455                                 if(next2==end())
 456                                 {
 457                                         weight=(end_sample)-iter2->pos;
 458                                         pool+=ColorAccumulator(iter2->color).premult_alpha()*weight;
 459                                         divisor+=weight;
 460                                         break;
 461                                 }
 462                                 pool+=supersample_helper(*iter2, *next2, begin_sample, end_sample, weight);
 463                                 divisor+=weight;
 464                                 iter2=next2++;
 465                         }
 466
 467                         if(divisor && pool.get_a() && pool.is_valid())
 468                         {
 469 /*
 470                                 pool.set_r(pool.get_r()/pool.get_a());
 471                                 pool.set_g(pool.get_g()/pool.get_a());
 472                                 pool.set_b(pool.get_b()/pool.get_a());
 473                                 pool.set_a(pool.get_a()/divisor);
 474 */
 475                                 pool/=divisor;
 476                                 pool.set_r(pool.get_r()/pool.get_a());
 477                                 pool.set_g(pool.get_g()/pool.get_a());
 478                                 pool.set_b(pool.get_b()/pool.get_a());
 479                                 if(pool.is_valid())
 480                                         return pool;
 481                                 else
 482                                         return Color::alpha();
 483                         }
 484                         else
 485                                 return Color::alpha();
 486                 }
 487         }
 488
 489         // We should never get to this point.
 490
 491         synfig::error("synfig::Gradient::operator()(): Logic Error (x=%f)",x);
 492         assert(0);
 493         throw std::logic_error(strprintf("synfig::Gradient::operator()(): Logic Error (x=%f)",x));
 494 }
 495
 496 synfig::Gradient::iterator
 497 synfig::Gradient::proximity(const Real &x)
 498 {
 499         iterator iter;
 500         float dist(100000000);
 501         float prev_pos(-0230);
 502         // This algorithm requires a sorted list.
 503         for(iter=begin();iter<end();iter++)
 504         {
 505                 float new_dist;
 506
 507                 if(prev_pos==iter->pos)
 508                         new_dist=(abs(x-iter->pos-0.00001));
 509                 else
 510                         new_dist=(abs(x-iter->pos));
 511
 512                 if(new_dist>dist)
 513                 {
 514                         iter--;
 515                         return iter;
 516                 }
 517                 dist=new_dist;
 518                 prev_pos=iter->pos;
 519         }
 520         iter--;
 521         return iter;
 522 }
 523
 524 synfig::Gradient::const_iterator
 525 synfig::Gradient::proximity(const Real &x)const
 526 {
 527         return const_cast<Gradient*>(this)->proximity(x);
 528         /*
 529         const_iterator iter;
 530         float dist(100000000);
 531
 532         // This algorithm requires a sorted list.
 533         for(iter=begin();iter<end();iter++)
 534         {
 535                 const float new_dist(abs(x-iter->pos));
 536                 if(new_dist>dist)
 537                 {
 538                         iter--;
 539                         return iter;
 540                 }
 541                 dist=new_dist;
 542         }
 543         iter--;
 544         return iter;
 545         */
 546 }
 547
 548 synfig::Gradient::iterator
 549 synfig::Gradient::find(const UniqueID &id)
 550 {
 551         iterator iter;
 552
 553         for(iter=begin();iter<end();iter++)
 554         {
 555                 if(id==*iter)
 556                         return iter;
 557         }
 558
 559         throw Exception::NotFound("synfig::Gradient::find(): Unable to find UniqueID in gradient");
 560 }
 561
 562 synfig::Gradient::const_iterator
 563 synfig::Gradient::find(const UniqueID &id)const
 564 {
 565         const_iterator iter;
 566
 567         for(iter=begin();iter<end();iter++)
 568         {
 569                 if(id==*iter)
 570                         return iter;
 571         }
 572
 573         throw Exception::NotFound("synfig::Gradient::find()const: Unable to find UniqueID in gradient");
 574 }