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