cinelerra-5.1/plugins/threshold/threshold.C

   1
   2 /*
   3  * CINELERRA
   4  * Copyright (C) 2008 Adam Williams <broadcast at earthling dot net>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  *
  20  */
  21
  22 #include <string>
  23 #include <string.h>
  24
  25 #include "clip.h"
  26 #include "bchash.h"
  27 #include "filexml.h"
  28 #include "histogramengine.h"
  29 #include "language.h"
  30 #include "bccolors.h"
  31 #include "threshold.h"
  32 #include "thresholdwindow.h"
  33 #include "vframe.h"
  34
  35 ;
  36 using ::std::string;
  37
  38
  39
  40 ThresholdConfig::ThresholdConfig()
  41 {
  42         reset();
  43 }
  44
  45 int ThresholdConfig::equivalent(ThresholdConfig &that)
  46 {
  47         return EQUIV(min, that.min) &&
  48                 EQUIV(max, that.max) &&
  49                 plot == that.plot &&
  50                 low_color == that.low_color &&
  51                 mid_color == that.mid_color &&
  52                 high_color == that.high_color;
  53 }
  54
  55 void ThresholdConfig::copy_from(ThresholdConfig &that)
  56 {
  57         min = that.min;
  58         max = that.max;
  59         plot = that.plot;
  60         low_color = that.low_color;
  61         mid_color = that.mid_color;
  62         high_color = that.high_color;
  63 }
  64
  65 // General purpose scale function.
  66 template<typename T>
  67 T interpolate(const T & prev, const double & prev_scale, const T & next, const double & next_scale)
  68 {
  69         return static_cast<T>(prev * prev_scale + next * next_scale);
  70 }
  71
  72 void ThresholdConfig::interpolate(ThresholdConfig &prev,
  73         ThresholdConfig &next,
  74         int64_t prev_frame,
  75         int64_t next_frame,
  76         int64_t current_frame)
  77 {
  78         double next_scale = (double)(current_frame - prev_frame) /
  79                 (next_frame - prev_frame);
  80         double prev_scale = (double)(next_frame - current_frame) /
  81                 (next_frame - prev_frame);
  82
  83         min = ::interpolate(prev.min, prev_scale, next.min, next_scale);
  84         max = ::interpolate(prev.max, prev_scale, next.max, next_scale);
  85         plot = prev.plot;
  86
  87         low_color =  ::interpolate(prev.low_color,  prev_scale, next.low_color,  next_scale);
  88         mid_color =  ::interpolate(prev.mid_color,  prev_scale, next.mid_color,  next_scale);
  89         high_color = ::interpolate(prev.high_color, prev_scale, next.high_color, next_scale);
  90 }
  91
  92 void ThresholdConfig::reset()
  93 {
  94         min = 0.0;
  95         max = 1.0;
  96         plot = 1;
  97         low_color.set (0x0,  0x0,  0x0,  0xff);
  98         mid_color.set (0xff, 0xff, 0xff, 0xff);
  99         high_color.set(0x0,  0x0,  0x0,  0xff);
 100 }
 101
 102 void ThresholdConfig::boundaries()
 103 {
 104         CLAMP(min, HISTOGRAM_MIN, max);
 105         CLAMP(max, min, HISTOGRAM_MAX);
 106 }
 107
 108
 109
 110
 111
 112
 113
 114
 115 REGISTER_PLUGIN(ThresholdMain)
 116
 117 ThresholdMain::ThresholdMain(PluginServer *server)
 118  : PluginVClient(server)
 119 {
 120         engine = 0;
 121         threshold_engine = 0;
 122 }
 123
 124 ThresholdMain::~ThresholdMain()
 125 {
 126         delete engine;
 127         delete threshold_engine;
 128 }
 129
 130 const char* ThresholdMain::plugin_title() { return _("Threshold"); }
 131 int ThresholdMain::is_realtime() { return 1; }
 132
 133
 134
 135 LOAD_CONFIGURATION_MACRO(ThresholdMain, ThresholdConfig)
 136
 137
 138
 139
 140
 141
 142
 143 int ThresholdMain::process_buffer(VFrame *frame,
 144         int64_t start_position,
 145         double frame_rate)
 146 {
 147         load_configuration();
 148
 149         int use_opengl = get_use_opengl() &&
 150                 (!config.plot || !gui_open());
 151
 152         read_frame(frame,
 153                 0,
 154                 get_source_position(),
 155                 get_framerate(),
 156                 use_opengl);
 157
 158         if(use_opengl) return run_opengl();
 159
 160         send_render_gui(frame);
 161
 162         if(!threshold_engine)
 163                 threshold_engine = new ThresholdEngine(this);
 164         threshold_engine->process_packages(frame);
 165
 166         return 0;
 167 }
 168
 169 void ThresholdMain::save_data(KeyFrame *keyframe)
 170 {
 171         FileXML output;
 172         output.set_shared_output(keyframe->get_data(), MESSAGESIZE);
 173         output.tag.set_title("THRESHOLD");
 174         output.tag.set_property("MIN", config.min);
 175         output.tag.set_property("MAX", config.max);
 176         output.tag.set_property("PLOT", config.plot);
 177         config.low_color.set_property(output.tag,  "LOW_COLOR");
 178         config.mid_color.set_property(output.tag,  "MID_COLOR");
 179         config.high_color.set_property(output.tag, "HIGH_COLOR");
 180         output.append_tag();
 181         output.tag.set_title("/THRESHOLD");
 182         output.append_tag();
 183         output.append_newline();
 184         output.terminate_string();
 185 }
 186
 187 void ThresholdMain::read_data(KeyFrame *keyframe)
 188 {
 189         FileXML input;
 190         const char *data = keyframe->get_data();
 191         input.set_shared_input((char *)data, strlen(data));
 192         int result = 0;
 193         while(!result)
 194         {
 195                 result = input.read_tag();
 196                 if(!result)
 197                 {
 198                         config.min = input.tag.get_property("MIN", config.min);
 199                         config.max = input.tag.get_property("MAX", config.max);
 200                         config.plot = input.tag.get_property("PLOT", config.plot);
 201                         config.low_color = config.low_color.get_property(input.tag, "LOW_COLOR");
 202                         config.mid_color = config.mid_color.get_property(input.tag, "MID_COLOR");
 203                         config.high_color = config.high_color.get_property(input.tag, "HIGH_COLOR");
 204                 }
 205         }
 206         config.boundaries();
 207 }
 208
 209 NEW_WINDOW_MACRO(ThresholdMain,ThresholdWindow);
 210
 211 void ThresholdMain::update_gui()
 212 {
 213         if(thread)
 214         {
 215                 thread->window->lock_window("ThresholdMain::update_gui");
 216                 if(load_configuration())
 217                 {
 218                         ThresholdWindow *window = (ThresholdWindow*) thread->window;
 219                         window->min->update(config.min);
 220                         window->max->update(config.max);
 221                         window->plot->update(config.plot);
 222                         window->update_low_color();
 223                         window->update_mid_color();
 224                         window->update_high_color();
 225                         window->low_color_thread->update_gui(config.low_color.getRGB(), config.low_color.a);
 226                         window->mid_color_thread->update_gui(config.mid_color.getRGB(), config.mid_color.a);
 227                         window->high_color_thread->update_gui(config.high_color.getRGB(), config.high_color.a);
 228                 }
 229                 thread->window->unlock_window();
 230         }
 231 }
 232
 233 void ThresholdMain::render_gui(void *data)
 234 {
 235         if(thread)
 236         {
 237                 calculate_histogram((VFrame*)data);
 238                 ThresholdWindow *window = (ThresholdWindow*) thread->window;
 239                 window->lock_window("ThresholdMain::render_gui");
 240                 window->canvas->draw();
 241                 window->unlock_window();
 242         }
 243 }
 244
 245 void ThresholdMain::calculate_histogram(VFrame *frame)
 246 {
 247         if(!engine) engine = new HistogramEngine(get_project_smp() + 1,
 248                 get_project_smp() + 1);
 249         engine->process_packages(frame);
 250 }
 251
 252 int ThresholdMain::handle_opengl()
 253 {
 254 #ifdef HAVE_GL
 255         static const char *rgb_shader =
 256                 "uniform sampler2D tex;\n"
 257                 "uniform float min;\n"
 258                 "uniform float max;\n"
 259                 "uniform vec4 low_color;\n"
 260                 "uniform vec4 mid_color;\n"
 261                 "uniform vec4 high_color;\n"
 262                 "void main()\n"
 263                 "{\n"
 264                 "       vec4 pixel = texture2D(tex, gl_TexCoord[0].st);\n"
 265                 "       float v = dot(pixel.rgb, vec3(0.299, 0.587, 0.114));\n"
 266                 "       if(v < min)\n"
 267                 "               pixel = low_color;\n"
 268                 "       else if(v < max)\n"
 269                 "               pixel = mid_color;\n"
 270                 "       else\n"
 271                 "               pixel = high_color;\n"
 272                 "       gl_FragColor = pixel;\n"
 273                 "}\n";
 274
 275         static const char *yuv_shader =
 276                 "uniform sampler2D tex;\n"
 277                 "uniform float min;\n"
 278                 "uniform float max;\n"
 279                 "uniform vec4 low_color;\n"
 280                 "uniform vec4 mid_color;\n"
 281                 "uniform vec4 high_color;\n"
 282                 "void main()\n"
 283                 "{\n"
 284                 "       vec4 pixel = texture2D(tex, gl_TexCoord[0].st);\n"
 285                 "       if(pixel.r < min)\n"
 286                 "               pixel = low_color;\n"
 287                 "       else if(pixel.r < max)\n"
 288                 "               pixel = mid_color;\n"
 289                 "       else\n"
 290                 "               pixel = high_color;\n"
 291                 "       gl_FragColor = pixel;\n"
 292                 "}\n";
 293
 294         get_output()->to_texture();
 295         get_output()->enable_opengl();
 296
 297         unsigned int shader = 0;
 298         int color_model = get_output()->get_color_model();
 299         bool is_yuv = BC_CModels::is_yuv(color_model);
 300         bool has_alpha = BC_CModels::has_alpha(color_model);
 301         if(is_yuv)
 302                 shader = VFrame::make_shader(0, yuv_shader, 0);
 303         else
 304                 shader = VFrame::make_shader(0, rgb_shader, 0);
 305
 306         if(shader > 0)
 307         {
 308                 glUseProgram(shader);
 309                 glUniform1i(glGetUniformLocation(shader, "tex"), 0);
 310                 glUniform1f(glGetUniformLocation(shader, "min"), config.min);
 311                 glUniform1f(glGetUniformLocation(shader, "max"), config.max);
 312
 313                 if (is_yuv)
 314                 {
 315                         float y_low,  u_low,  v_low;
 316                         float y_mid,  u_mid,  v_mid;
 317                         float y_high, u_high, v_high;
 318
 319                         YUV::yuv.rgb_to_yuv_f((float)config.low_color.r / 0xff,
 320                                           (float)config.low_color.g / 0xff,
 321                                           (float)config.low_color.b / 0xff,
 322                                           y_low,
 323                                           u_low,
 324                                           v_low);
 325                         u_low += 0.5;
 326                         v_low += 0.5;
 327                         YUV::yuv.rgb_to_yuv_f((float)config.mid_color.r / 0xff,
 328                                           (float)config.mid_color.g / 0xff,
 329                                           (float)config.mid_color.b / 0xff,
 330                                           y_mid,
 331                                           u_mid,
 332                                           v_mid);
 333                         u_mid += 0.5;
 334                         v_mid += 0.5;
 335                         YUV::yuv.rgb_to_yuv_f((float)config.high_color.r / 0xff,
 336                                           (float)config.high_color.g / 0xff,
 337                                           (float)config.high_color.b / 0xff,
 338                                           y_high,
 339                                           u_high,
 340                                           v_high);
 341                         u_high += 0.5;
 342                         v_high += 0.5;
 343
 344                         glUniform4f(glGetUniformLocation(shader, "low_color"),
 345                                     y_low, u_low, v_low,
 346                                     has_alpha ? (float)config.low_color.a / 0xff : 1.0);
 347                         glUniform4f(glGetUniformLocation(shader, "mid_color"),
 348                                     y_mid, u_mid, v_mid,
 349                                     has_alpha ? (float)config.mid_color.a / 0xff : 1.0);
 350                         glUniform4f(glGetUniformLocation(shader, "high_color"),
 351                                     y_high, u_high, v_high,
 352                                     has_alpha ? (float)config.high_color.a / 0xff : 1.0);
 353                 } else {
 354                         glUniform4f(glGetUniformLocation(shader, "low_color"),
 355                                     (float)config.low_color.r / 0xff,
 356                                     (float)config.low_color.g / 0xff,
 357                                     (float)config.low_color.b / 0xff,
 358                                     has_alpha ? (float)config.low_color.a / 0xff : 1.0);
 359                         glUniform4f(glGetUniformLocation(shader, "mid_color"),
 360                                     (float)config.mid_color.r / 0xff,
 361                                     (float)config.mid_color.g / 0xff,
 362                                     (float)config.mid_color.b / 0xff,
 363                                     has_alpha ? (float)config.mid_color.a / 0xff : 1.0);
 364                         glUniform4f(glGetUniformLocation(shader, "high_color"),
 365                                     (float)config.high_color.r / 0xff,
 366                                     (float)config.high_color.g / 0xff,
 367                                     (float)config.high_color.b / 0xff,
 368                                     has_alpha ? (float)config.high_color.a / 0xff : 1.0);
 369                 }
 370         }
 371
 372         get_output()->init_screen();
 373         get_output()->bind_texture(0);
 374         get_output()->draw_texture();
 375         glUseProgram(0);
 376         get_output()->set_opengl_state(VFrame::SCREEN);
 377 #endif
 378         return 0;
 379 }
 380
 381
 382
 383
 384
 385
 386
 387
 388
 389
 390
 391
 392
 393
 394
 395
 396
 397
 398
 399
 400
 401
 402 ThresholdPackage::ThresholdPackage()
 403  : LoadPackage()
 404 {
 405         start = end = 0;
 406 }
 407
 408
 409
 410
 411
 412
 413
 414
 415
 416
 417
 418 ThresholdUnit::ThresholdUnit(ThresholdEngine *server)
 419  : LoadClient(server)
 420 {
 421         this->server = server;
 422 }
 423
 424 // Coerces pixel component to int.
 425 static inline int get_component(unsigned char v)
 426 {
 427         return (v << 8) | v;
 428 }
 429
 430 static inline int get_component(float v)
 431 {
 432         return (int)(v * 0xffff);
 433 }
 434
 435 static inline int get_component(uint16_t v)
 436 {
 437         return v;
 438 }
 439
 440 // Rescales value in range [0, 255] to range appropriate to TYPE.
 441 template<typename TYPE>
 442 static TYPE scale_to_range(int v)
 443 {
 444         return v;  // works for unsigned char, override for the rest.
 445 }
 446
 447 template<>
 448 inline float scale_to_range(int v)
 449 {
 450         return (float) v / 0xff;
 451 }
 452
 453 template<>
 454 inline uint16_t scale_to_range(int v)
 455 {
 456         return v << 8 | v;
 457 }
 458
 459 static inline void rgb_to_yuv(unsigned char   r, unsigned char   g, unsigned char   b,
 460                               unsigned char & y, unsigned char & u, unsigned char & v)
 461 {
 462         YUV::yuv.rgb_to_yuv_8(r, g, b, y, u, v);
 463 }
 464
 465 static inline void rgb_to_yuv(float   r, float   g, float   b,
 466                               float & y, float & u, float & v)
 467 {
 468         YUV::yuv.rgb_to_yuv_f(r, g, b, y, u, v);
 469 }
 470
 471 static inline void rgb_to_yuv(uint16_t   r, uint16_t   g, uint16_t   b,
 472                               uint16_t & y, uint16_t & u, uint16_t & v)
 473 {
 474         YUV::yuv.rgb_to_yuv_16(r, g, b, y, u, v);
 475 }
 476
 477 template<typename TYPE, int COMPONENTS, bool USE_YUV>
 478 void ThresholdUnit::render_data(LoadPackage *package)
 479 {
 480         const ThresholdPackage *pkg = (ThresholdPackage*)package;
 481         const ThresholdConfig *config = & server->plugin->config;
 482         VFrame *data = server->data;
 483         const int min = (int)(config->min * 0xffff);
 484         const int max = (int)(config->max * 0xffff);
 485         const int w = data->get_w();
 486         //const int h = data->get_h();
 487
 488         const TYPE r_low = scale_to_range<TYPE>(config->low_color.r);
 489         const TYPE g_low = scale_to_range<TYPE>(config->low_color.g);
 490         const TYPE b_low = scale_to_range<TYPE>(config->low_color.b);
 491         const TYPE a_low = scale_to_range<TYPE>(config->low_color.a);
 492
 493         const TYPE r_mid = scale_to_range<TYPE>(config->mid_color.r);
 494         const TYPE g_mid = scale_to_range<TYPE>(config->mid_color.g);
 495         const TYPE b_mid = scale_to_range<TYPE>(config->mid_color.b);
 496         const TYPE a_mid = scale_to_range<TYPE>(config->mid_color.a);
 497
 498         const TYPE r_high = scale_to_range<TYPE>(config->high_color.r);
 499         const TYPE g_high = scale_to_range<TYPE>(config->high_color.g);
 500         const TYPE b_high = scale_to_range<TYPE>(config->high_color.b);
 501         const TYPE a_high = scale_to_range<TYPE>(config->high_color.a);
 502
 503         TYPE y_low,  u_low,  v_low;
 504         TYPE y_mid,  u_mid,  v_mid;
 505         TYPE y_high, u_high, v_high;
 506
 507         if (USE_YUV)
 508         {
 509                 rgb_to_yuv(r_low,  g_low,  b_low,  y_low,  u_low,  v_low);
 510                 rgb_to_yuv(r_mid,  g_mid,  b_mid,  y_mid,  u_mid,  v_mid);
 511                 rgb_to_yuv(r_high, g_high, b_high, y_high, u_high, v_high);
 512         }
 513
 514         for(int i = pkg->start; i < pkg->end; i++)
 515         {
 516                 TYPE *in_row = (TYPE*)data->get_rows()[i];
 517                 TYPE *out_row = in_row;
 518                 for(int j = 0; j < w; j++)
 519                 {
 520                         if (USE_YUV)
 521                         {
 522                                 const int y = get_component(in_row[0]);
 523                                 if (y < min)
 524                                 {
 525                                         *out_row++ = y_low;
 526                                         *out_row++ = u_low;
 527                                         *out_row++ = v_low;
 528                                         if(COMPONENTS == 4) *out_row++ = a_low;
 529                                 }
 530                                 else if (y < max)
 531                                 {
 532                                         *out_row++ = y_mid;
 533                                         *out_row++ = u_mid;
 534                                         *out_row++ = v_mid;
 535                                         if(COMPONENTS == 4) *out_row++ = a_mid;
 536                                 }
 537                                 else
 538                                 {
 539                                         *out_row++ = y_high;
 540                                         *out_row++ = u_high;
 541                                         *out_row++ = v_high;
 542                                         if(COMPONENTS == 4) *out_row++ = a_high;
 543                                 }
 544                         }
 545                         else
 546                         {
 547                                 const int r = get_component(in_row[0]);
 548                                 const int g = get_component(in_row[1]);
 549                                 const int b = get_component(in_row[2]);
 550                                 const int y = (r * 76 + g * 150 + b * 29) >> 8;
 551                                 if (y < min)
 552                                 {
 553                                         *out_row++ = r_low;
 554                                         *out_row++ = g_low;
 555                                         *out_row++ = b_low;
 556                                         if(COMPONENTS == 4) *out_row++ = a_low;
 557                                 }
 558                                 else if (y < max)
 559                                 {
 560                                         *out_row++ = r_mid;
 561                                         *out_row++ = g_mid;
 562                                         *out_row++ = b_mid;
 563                                         if(COMPONENTS == 4) *out_row++ = a_mid;
 564                                 }
 565                                 else
 566                                 {
 567                                         *out_row++ = r_high;
 568                                         *out_row++ = g_high;
 569                                         *out_row++ = b_high;
 570                                         if(COMPONENTS == 4) *out_row++ = a_high;
 571                                 }
 572                         }
 573                         in_row += COMPONENTS;
 574                 }
 575         }
 576 }
 577
 578 void ThresholdUnit::process_package(LoadPackage *package)
 579 {
 580         switch(server->data->get_color_model())
 581         {
 582                 case BC_RGB888:
 583                         render_data<unsigned char, 3, false>(package);
 584                         break;
 585
 586                 case BC_RGB_FLOAT:
 587                         render_data<float, 3, false>(package);
 588                         break;
 589
 590                 case BC_RGBA8888:
 591                         render_data<unsigned char, 4, false>(package);
 592                         break;
 593
 594                 case BC_RGBA_FLOAT:
 595                         render_data<float, 4, false>(package);
 596                         break;
 597
 598                 case BC_YUV888:
 599                         render_data<unsigned char, 3, true>(package);
 600                         break;
 601
 602                 case BC_YUVA8888:
 603                         render_data<unsigned char, 4, true>(package);
 604                         break;
 605
 606                 case BC_YUV161616:
 607                         render_data<uint16_t, 3, true>(package);
 608                         break;
 609
 610                 case BC_YUVA16161616:
 611                         render_data<uint16_t, 4, true>(package);
 612                         break;
 613         }
 614 }
 615
 616
 617
 618
 619
 620
 621
 622
 623
 624
 625
 626 ThresholdEngine::ThresholdEngine(ThresholdMain *plugin)
 627  : LoadServer(plugin->get_project_smp() + 1,
 628         plugin->get_project_smp() + 1)
 629 {
 630         this->plugin = plugin;
 631 }
 632
 633 ThresholdEngine::~ThresholdEngine()
 634 {
 635 }
 636
 637 void ThresholdEngine::process_packages(VFrame *data)
 638 {
 639         this->data = data;
 640         LoadServer::process_packages();
 641 }
 642
 643 void ThresholdEngine::init_packages()
 644 {
 645         for(int i = 0; i < get_total_packages(); i++)
 646         {
 647                 ThresholdPackage *package = (ThresholdPackage*)get_package(i);
 648                 package->start = data->get_h() * i / get_total_packages();
 649                 package->end = data->get_h() * (i + 1) / get_total_packages();
 650         }
 651 }
 652
 653 LoadClient* ThresholdEngine::new_client()
 654 {
 655         return (LoadClient*)new ThresholdUnit(this);
 656 }
 657
 658 LoadPackage* ThresholdEngine::new_package()
 659 {
 660         return (LoadPackage*)new HistogramPackage;
 661 }
 662
 663
 664
 665
 666
 667
 668
 669
 670 RGBA::RGBA()
 671 {
 672         r = g = b = a = 0;
 673 }
 674
 675 RGBA::RGBA(int r, int g, int b, int a)
 676 {
 677         this->r = r;
 678         this->g = g;
 679         this->b = b;
 680         this->a = a;
 681 }
 682
 683 void RGBA::set(int r, int g, int b, int a)
 684 {
 685         this->r = r;
 686         this->g = g;
 687         this->b = b;
 688         this->a = a;
 689 }
 690
 691 void RGBA::set(int rgb, int alpha)
 692 {
 693         r = (rgb & 0xff0000) >> 16;
 694         g = (rgb & 0xff00)   >>  8;
 695         b = (rgb & 0xff);
 696         a = alpha;
 697 }
 698
 699 int RGBA::getRGB() const
 700 {
 701         return r << 16 | g << 8 | b;
 702 }
 703
 704 static void init_RGBA_keys(const char * prefix,
 705                            string & r_s,
 706                            string & g_s,
 707                            string & b_s,
 708                            string & a_s)
 709 {
 710         r_s = prefix;
 711         g_s = prefix;
 712         b_s = prefix;
 713         a_s = prefix;
 714
 715         r_s += "_R";
 716         g_s += "_G";
 717         b_s += "_B";
 718         a_s += "_A";
 719 }
 720
 721 void RGBA::set_property(XMLTag & tag, const char * prefix) const
 722 {
 723         string r_s, g_s, b_s, a_s;
 724         init_RGBA_keys(prefix, r_s, g_s, b_s, a_s);
 725
 726         tag.set_property(const_cast<char *>(r_s.c_str()), r);
 727         tag.set_property(const_cast<char *>(g_s.c_str()), g);
 728         tag.set_property(const_cast<char *>(b_s.c_str()), b);
 729         tag.set_property(const_cast<char *>(a_s.c_str()), a);
 730 }
 731
 732 RGBA RGBA::get_property(XMLTag & tag, const char * prefix) const
 733 {
 734         string r_s, g_s, b_s, a_s;
 735         init_RGBA_keys(prefix, r_s, g_s, b_s, a_s);
 736
 737         return RGBA(tag.get_property(const_cast<char *>(r_s.c_str()), r),
 738                     tag.get_property(const_cast<char *>(g_s.c_str()), g),
 739                     tag.get_property(const_cast<char *>(b_s.c_str()), b),
 740                     tag.get_property(const_cast<char *>(a_s.c_str()), a));
 741 }
 742
 743 bool operator==(const RGBA & a, const RGBA & b)
 744 {
 745         return  a.r == b.r &&
 746                 a.g == b.g &&
 747                 a.b == b.b &&
 748                 a.a == b.a;
 749 }
 750
 751 template<>
 752 RGBA interpolate(const RGBA & prev_color, const double & prev_scale, const RGBA &next_color, const double & next_scale)
 753 {
 754         return RGBA(interpolate(prev_color.r, prev_scale, next_color.r, next_scale),
 755                     interpolate(prev_color.g, prev_scale, next_color.g, next_scale),
 756                     interpolate(prev_color.b, prev_scale, next_color.b, next_scale),
 757                     interpolate(prev_color.a, prev_scale, next_color.a, next_scale));
 758 }