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 Gradient &
 144 synfig::Gradient::operator+=(const Gradient &rhs)
 145 {
 146         CPointList ret;
 147         const_iterator iter1 = begin(), iter2 = rhs.begin(), left_same, right_same;
 148         CPoint left, right;
 149         if (iter1 != end()) left = *iter1;
 150         if (iter2 != rhs.end()) right = *iter2;
 151         if (iter1 != end() && iter2 != rhs.end())
 152                 while(true)
 153                 {
 154                         if (left.pos < right.pos)
 155                         {
 156                                 ret.push_back(CPoint(left.pos, left.color + rhs(left.pos)));
 157                                 if(++iter1 == end()) break;
 158                                 left=*iter1;
 159                         }
 160                         else if (left.pos > right.pos)
 161                         {
 162                                 ret.push_back(CPoint(right.pos, right.color + (*this)(right.pos)));
 163                                 if(++iter2 == rhs.end()) break;
 164                                 right=*iter2;
 165                         }
 166                         else
 167                         {
 168                                 for(left_same = iter1++; (*iter1).pos == left.pos; iter1++);
 169                                 for(right_same = iter2++; (*iter2).pos == right.pos; iter2++);
 170                                 if (iter1 == left_same+1 && iter2 == right_same+1)
 171                                         ret.push_back(CPoint(left.pos, left.color + right.color));
 172                                 else
 173                                 {
 174                                         ret.push_back(CPoint(left.pos, left.color + right.color));
 175                                         ret.push_back(CPoint(left.pos, (*(iter1-1)).color + (*(iter2-1)).color));
 176                                 }
 177                                 if (iter1 != end()) left=*iter1;
 178                                 if (iter2 == rhs.end()) break;
 179                                 right = *iter2;
 180                                 if (iter1 == end()) break;
 181                         }
 182                 }
 183
 184         if (iter1 != end())
 185                 while(true)
 186                 {
 187                         ret.push_back(CPoint(left.pos, left.color + rhs(left.pos)));
 188                         if(++iter1 == end()) break;
 189                         left = *iter1;
 190                 }
 191
 192         if (iter2 != rhs.end())
 193                 while(true)
 194                 {
 195                         ret.push_back(CPoint(right.pos, right.color + (*this)(right.pos)));
 196                         if(++iter2 == rhs.end()) break;
 197                         right = *iter2;
 198                 }
 199
 200         cpoints = ret;
 201         return *this;
 202 }
 203
 204 Gradient &
 205 synfig::Gradient::operator-=(const Gradient &rhs)
 206 {
 207         return (*this)+=(rhs*-1);
 208 }
 209
 210 Gradient &
 211 synfig::Gradient::operator*=(const float    &rhs)
 212 {
 213         if (rhs == 0)
 214                 cpoints.clear();
 215         else
 216                 for (iterator iter = cpoints.begin(); iter!=cpoints.end(); iter++)
 217                         (*iter).color *= rhs;
 218         return *this;
 219 }
 220
 221 Gradient &
 222 synfig::Gradient::operator/=(const float    &rhs)
 223 {
 224         for (iterator iter = cpoints.begin(); iter!=cpoints.end(); iter++)
 225                 (*iter).color /= rhs;
 226         return *this;
 227 }
 228
 229 Color
 230 synfig::Gradient::operator()(const Real &x,float supersample)const
 231 {
 232         if(cpoints.empty())
 233                 return Color(0,0,0,0);
 234         if(supersample<0)
 235                 supersample=-supersample;
 236         if(supersample>2.0)
 237                 supersample=2.0f;
 238
 239         float begin_sample(x-supersample*0.5);
 240         float end_sample(x+supersample*0.5);
 241
 242         if(cpoints.size()==1 || end_sample<=cpoints.front().pos || isnan(x))
 243                 return cpoints.front().color;
 244
 245         if(begin_sample>=cpoints.back().pos)
 246                 return cpoints.back().color;
 247
 248         /*
 249         if(end_sample>=back().pos)
 250                 end_sample=back().pos;
 251
 252         if(begin_sample<=front().pos)
 253                 begin_sample=front().pos;
 254         */
 255
 256         const_iterator iter,next;
 257
 258         /*
 259         //optimizize...
 260         Real    left = x-supersample/2, right = x+supersample/2;
 261
 262         if(left < front().pos) left = front().pos;
 263         if(right > back().pos) right = back().pos;
 264
 265         //find using binary search...
 266         const_iterator iterl,iterr;
 267
 268         //the binary search should give us the values BEFORE the point we're looking for...
 269         iterl = binary_find(begin(),end(),left);
 270         iterr = binary_find(iterl,end(),right);
 271
 272         //now integrate over the range of left to right...
 273
 274         if(iterl == iterr)
 275         {
 276                 iterr++; //let's look at the next one shall we :)
 277
 278                 //interpolate neighboring colors
 279                 const Real one = iterr->pos - iterl->pos;
 280                 const Real lambda = (x - iterl->pos)/one;
 281
 282                 //(1-l)iterl + (l)iterr
 283                 return iterl->color.premult_alpha()*(1-lambda) + iterr->color.premult_alpha()*lambda;
 284
 285                 //return Color::blend(iterr->color,iterl->color,lambda,Color::BLEND_STRAIGHT);
 286         }else
 287         {
 288                 //itegration madness
 289                 const_iterator i = iterl, ie = iterr+1;
 290                 Real wlast = left;
 291
 292                 ColorAccumulator clast,cwork;
 293                 {
 294                         const Real lambda = (x - iterl->pos)/(iterr->pos - iterl->pos);
 295
 296                         //premultiply because that's the form in which we can combine things...
 297                         clast = iterl->color.premult_alpha()*(1-lambda) + iterr->color.premult_alpha()*lambda;
 298                         //Color::blend((i+1)->color,i->color,(left - i->pos)/((i+1)->pos - i->pos),Color::BLEND_STRAIGHT);
 299                 }
 300
 301                 ColorAccumulator        accum = 0;
 302
 303                 //loop through all the trapezoids and integrate them as we go...
 304                 //      area of trap = (yi + yi1)*(xi1 - xi)
 305                 //      yi = clast, xi = wlast, yi1 = i->color, xi1 = i->pos
 306
 307                 for(;i<=iterr; wlast=i->pos,clast=i->color.premult_alpha(),++i)
 308                 {
 309                         const Real diff = i->pos - wlast;
 310                         if(diff > 0) //only accumulate if there will be area to add
 311                         {
 312                                 cwork = i->color.premult_alpha();
 313                                 accum += (cwork + clast)*diff;
 314                         }
 315                 }
 316
 317                 {
 318                         const_iterator ibef = i-1;
 319                         const Real diff = right - ibef->pos;
 320
 321                         if(diff > 0)
 322                         {
 323                                 const Real lambda = diff/(i->pos - ibef->pos);
 324                                 cwork = ibef->color.premult_alpha()*(1-lambda) + i->color.premult_alpha()*lambda;
 325
 326                                 accum += (cwork + clast)*diff; //can probably optimize this more... but it's not too bad
 327                         }
 328                 }
 329
 330                 accum /= supersample; //should be the total area it was sampled over...
 331                 return accum.demult_alpha();
 332         }*/
 333
 334         next=begin(),iter=next++;
 335
 336         //add for optimization
 337         next = binary_find(begin(),end(),(Real)begin_sample);
 338         iter = next++;
 339
 340         //! As a future optimization, this could be performed faster
 341         //! using a binary search.
 342         for(;iter<end();iter=next++)
 343         {
 344                 if(next==end() || x>=iter->pos &&  x<next->pos && iter->pos!=next->pos)
 345                 {
 346                         // If the supersample region falls square in between
 347                         // two CPoints, then we don't have to do anything special.
 348                         if(next!=end() && (!supersample || (iter->pos<=begin_sample && next->pos>=end_sample)))
 349                         {
 350                                 const Real dist(next->pos-iter->pos);
 351                                 const Real pos(x-iter->pos);
 352                                 const Real amount(pos/dist);
 353                                 return Color::blend(next->color,iter->color, amount, Color::BLEND_STRAIGHT);
 354                         }
 355                         // In this case our supersample region extends over one or more
 356                         // CPoints. So, we need to calculate our coverage amount.
 357                         ColorAccumulator pool(Color::alpha());
 358                         float divisor(0.0),weight(0);
 359
 360                         const_iterator iter2,next2;
 361                         iter2=iter;
 362                         if(iter==begin() && iter->pos>x)
 363                         {
 364                                 weight=x-iter->pos;
 365                                 //weight*=iter->color.get_a();
 366                                 pool+=ColorAccumulator(iter->color).premult_alpha()*weight;
 367                                 divisor+=weight;
 368                         }
 369                         else
 370                         {
 371                                 while(iter2->pos>=begin_sample)
 372                                 {
 373                                         if(iter2==begin())
 374                                         {
 375                                                 weight=iter2->pos-(begin_sample);
 376                                                 //weight*=iter2->color.get_a();
 377                                                 pool+=ColorAccumulator(iter2->color).premult_alpha()*weight;
 378                                                 divisor+=weight;
 379                                                 break;
 380                                         }
 381                                         next2=iter2--;
 382                                         pool+=supersample_helper(*iter2, *next2, begin_sample, end_sample, weight);
 383                                         divisor+=weight;
 384                                 }
 385                         }
 386
 387                         next2=iter;
 388                         iter2=next2++;
 389                         while(iter2->pos<=end_sample)
 390                         {
 391                                 if(next2==end())
 392                                 {
 393                                         weight=(end_sample)-iter2->pos;
 394                                         pool+=ColorAccumulator(iter2->color).premult_alpha()*weight;
 395                                         divisor+=weight;
 396                                         break;
 397                                 }
 398                                 pool+=supersample_helper(*iter2, *next2, begin_sample, end_sample, weight);
 399                                 divisor+=weight;
 400                                 iter2=next2++;
 401                         }
 402
 403                         if(divisor && pool.get_a() && pool.is_valid())
 404                         {
 405 /*
 406                                 pool.set_r(pool.get_r()/pool.get_a());
 407                                 pool.set_g(pool.get_g()/pool.get_a());
 408                                 pool.set_b(pool.get_b()/pool.get_a());
 409                                 pool.set_a(pool.get_a()/divisor);
 410 */
 411                                 pool/=divisor;
 412                                 pool.set_r(pool.get_r()/pool.get_a());
 413                                 pool.set_g(pool.get_g()/pool.get_a());
 414                                 pool.set_b(pool.get_b()/pool.get_a());
 415                                 if(pool.is_valid())
 416                                         return pool;
 417                                 else
 418                                         return Color::alpha();
 419                         }
 420                         else
 421                                 return Color::alpha();
 422                 }
 423         }
 424
 425         // We should never get to this point.
 426
 427         synfig::error("synfig::Gradient::operator()(): Logic Error (x=%f)",x);
 428         assert(0);
 429         throw std::logic_error(strprintf("synfig::Gradient::operator()(): Logic Error (x=%f)",x));
 430 }
 431
 432 synfig::Gradient::iterator
 433 synfig::Gradient::proximity(const Real &x)
 434 {
 435         iterator iter;
 436         float dist(100000000);
 437         float prev_pos(-0230);
 438         // This algorithm requires a sorted list.
 439         for(iter=begin();iter<end();iter++)
 440         {
 441                 float new_dist;
 442
 443                 if(prev_pos==iter->pos)
 444                         new_dist=(abs(x-iter->pos-0.00001));
 445                 else
 446                         new_dist=(abs(x-iter->pos));
 447
 448                 if(new_dist>dist)
 449                 {
 450                         iter--;
 451                         return iter;
 452                 }
 453                 dist=new_dist;
 454                 prev_pos=iter->pos;
 455         }
 456         iter--;
 457         return iter;
 458 }
 459
 460 synfig::Gradient::const_iterator
 461 synfig::Gradient::proximity(const Real &x)const
 462 {
 463         return const_cast<Gradient*>(this)->proximity(x);
 464         /*
 465         const_iterator iter;
 466         float dist(100000000);
 467
 468         // This algorithm requires a sorted list.
 469         for(iter=begin();iter<end();iter++)
 470         {
 471                 const float new_dist(abs(x-iter->pos));
 472                 if(new_dist>dist)
 473                 {
 474                         iter--;
 475                         return iter;
 476                 }
 477                 dist=new_dist;
 478         }
 479         iter--;
 480         return iter;
 481         */
 482 }
 483
 484 synfig::Gradient::iterator
 485 synfig::Gradient::find(const UniqueID &id)
 486 {
 487         iterator iter;
 488
 489         for(iter=begin();iter<end();iter++)
 490         {
 491                 if(id==*iter)
 492                         return iter;
 493         }
 494
 495         throw Exception::NotFound("synfig::Gradient::find(): Unable to find UniqueID in gradient");
 496 }
 497
 498 synfig::Gradient::const_iterator
 499 synfig::Gradient::find(const UniqueID &id)const
 500 {
 501         const_iterator iter;
 502
 503         for(iter=begin();iter<end();iter++)
 504         {
 505                 if(id==*iter)
 506                         return iter;
 507         }
 508
 509         throw Exception::NotFound("synfig::Gradient::find()const: Unable to find UniqueID in gradient");
 510 }