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 "threshold.h"
  26 #include "bccolors.h"
  27 #include "clip.h"
  28 #include "bchash.h"
  29 #include "filexml.h"
  30 #include "histogramengine.h"
  31 #include "language.h"
  32 #include "playback3d.h"
  33 #include "thresholdwindow.h"
  34 #include "vframe.h"
  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 N_("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                 "uniform vec3 rgb_to_y_vector;\n"
 263                 "uniform float yminf;\n"
 264                 "void main()\n"
 265                 "{\n"
 266                 "       vec4 pixel = texture2D(tex, gl_TexCoord[0].st);\n"
 267                 "       float v = dot(pixel.rgb, rgb_to_y_vector) + yminf;\n"
 268                 "       if(v < min)\n"
 269                 "               pixel = low_color;\n"
 270                 "       else if(v < max)\n"
 271                 "               pixel = mid_color;\n"
 272                 "       else\n"
 273                 "               pixel = high_color;\n"
 274                 "       gl_FragColor = pixel;\n"
 275                 "}\n";
 276
 277         static const char *yuv_shader =
 278                 "uniform sampler2D tex;\n"
 279                 "uniform float min;\n"
 280                 "uniform float max;\n"
 281                 "uniform vec4 low_color;\n"
 282                 "uniform vec4 mid_color;\n"
 283                 "uniform vec4 high_color;\n"
 284                 "void main()\n"
 285                 "{\n"
 286                 "       vec4 pixel = texture2D(tex, gl_TexCoord[0].st);\n"
 287                 "       if(pixel.r < min)\n"
 288                 "               pixel = low_color;\n"
 289                 "       else if(pixel.r < max)\n"
 290                 "               pixel = mid_color;\n"
 291                 "       else\n"
 292                 "               pixel = high_color;\n"
 293                 "       gl_FragColor = pixel;\n"
 294                 "}\n";
 295
 296         get_output()->to_texture();
 297         get_output()->enable_opengl();
 298
 299         int color_model = get_output()->get_color_model();
 300         bool is_yuv = BC_CModels::is_yuv(color_model);
 301         bool has_alpha = BC_CModels::has_alpha(color_model);
 302         unsigned int shader = VFrame::make_shader(0, is_yuv ? yuv_shader : rgb_shader, 0);
 303         if( shader > 0 ) {
 304                 glUseProgram(shader);
 305                 glUniform1i(glGetUniformLocation(shader, "tex"), 0);
 306                 glUniform1f(glGetUniformLocation(shader, "min"), config.min);
 307                 glUniform1f(glGetUniformLocation(shader, "max"), config.max);
 308
 309                 if (is_yuv) {
 310                         float y_low,  u_low,  v_low;
 311                         float y_mid,  u_mid,  v_mid;
 312                         float y_high, u_high, v_high;
 313
 314                         YUV::yuv.rgb_to_yuv_f(
 315                                         (float)config.low_color.r / 0xff,
 316                                         (float)config.low_color.g / 0xff,
 317                                         (float)config.low_color.b / 0xff,
 318                                         y_low, u_low, v_low);
 319                         u_low += 0.5;  v_low += 0.5;
 320                         YUV::yuv.rgb_to_yuv_f(
 321                                         (float)config.mid_color.r / 0xff,
 322                                         (float)config.mid_color.g / 0xff,
 323                                         (float)config.mid_color.b / 0xff,
 324                                         y_mid, u_mid, v_mid);
 325                         u_mid += 0.5;  v_mid += 0.5;
 326                         YUV::yuv.rgb_to_yuv_f(
 327                                         (float)config.high_color.r / 0xff,
 328                                         (float)config.high_color.g / 0xff,
 329                                         (float)config.high_color.b / 0xff,
 330                                         y_high, u_high, v_high);
 331                         u_high += 0.5;  v_high += 0.5;
 332
 333                         glUniform4f(glGetUniformLocation(shader, "low_color"),
 334                                         y_low, u_low, v_low,
 335                                         has_alpha ? (float)config.low_color.a / 0xff : 1.0);
 336                         glUniform4f(glGetUniformLocation(shader, "mid_color"),
 337                                         y_mid, u_mid, v_mid,
 338                                         has_alpha ? (float)config.mid_color.a / 0xff : 1.0);
 339                         glUniform4f(glGetUniformLocation(shader, "high_color"),
 340                                         y_high, u_high, v_high,
 341                                         has_alpha ? (float)config.high_color.a / 0xff : 1.0);
 342                 }
 343                 else {
 344                         glUniform4f(glGetUniformLocation(shader, "low_color"),
 345                                         (float)config.low_color.r / 0xff,
 346                                         (float)config.low_color.g / 0xff,
 347                                         (float)config.low_color.b / 0xff,
 348                                         has_alpha ? (float)config.low_color.a / 0xff : 1.0);
 349                         glUniform4f(glGetUniformLocation(shader, "mid_color"),
 350                                         (float)config.mid_color.r / 0xff,
 351                                         (float)config.mid_color.g / 0xff,
 352                                         (float)config.mid_color.b / 0xff,
 353                                         has_alpha ? (float)config.mid_color.a / 0xff : 1.0);
 354                         glUniform4f(glGetUniformLocation(shader, "high_color"),
 355                                         (float)config.high_color.r / 0xff,
 356                                         (float)config.high_color.g / 0xff,
 357                                         (float)config.high_color.b / 0xff,
 358                                         has_alpha ? (float)config.high_color.a / 0xff : 1.0);
 359                         BC_GL_RGB_TO_Y(shader);
 360                 }
 361         }
 362
 363         get_output()->init_screen();
 364         get_output()->bind_texture(0);
 365         get_output()->draw_texture();
 366         glUseProgram(0);
 367         get_output()->set_opengl_state(VFrame::SCREEN);
 368 #endif
 369         return 0;
 370 }
 371
 372
 373
 374
 375
 376
 377
 378
 379
 380
 381
 382
 383
 384
 385
 386
 387
 388
 389
 390
 391
 392
 393 ThresholdPackage::ThresholdPackage()
 394  : LoadPackage()
 395 {
 396         start = end = 0;
 397 }
 398
 399
 400
 401
 402
 403
 404
 405
 406
 407
 408
 409 ThresholdUnit::ThresholdUnit(ThresholdEngine *server)
 410  : LoadClient(server)
 411 {
 412         this->server = server;
 413 }
 414
 415 // Coerces pixel component to int.
 416 static inline int get_component(unsigned char v)
 417 {
 418         return (v << 8) | v;
 419 }
 420
 421 static inline int get_component(float v)
 422 {
 423         return (int)(v * 0xffff);
 424 }
 425
 426 static inline int get_component(uint16_t v)
 427 {
 428         return v;
 429 }
 430
 431 // Rescales value in range [0, 255] to range appropriate to TYPE.
 432 template<typename TYPE>
 433 static TYPE scale_to_range(int v)
 434 {
 435         return v;  // works for unsigned char, override for the rest.
 436 }
 437
 438 template<>
 439 inline float scale_to_range(int v)
 440 {
 441         return (float) v / 0xff;
 442 }
 443
 444 template<>
 445 inline uint16_t scale_to_range(int v)
 446 {
 447         return v << 8 | v;
 448 }
 449
 450 static inline void rgb_to_yuv(unsigned char   r, unsigned char   g, unsigned char   b,
 451                               unsigned char & y, unsigned char & u, unsigned char & v)
 452 {
 453         YUV::yuv.rgb_to_yuv_8(r, g, b, y, u, v);
 454 }
 455
 456 static inline void rgb_to_yuv(float   r, float   g, float   b,
 457                               float & y, float & u, float & v)
 458 {
 459         YUV::yuv.rgb_to_yuv_f(r, g, b, y, u, v);
 460 }
 461
 462 static inline void rgb_to_yuv(uint16_t   r, uint16_t   g, uint16_t   b,
 463                               uint16_t & y, uint16_t & u, uint16_t & v)
 464 {
 465         YUV::yuv.rgb_to_yuv_16(r, g, b, y, u, v);
 466 }
 467
 468 template<typename TYPE, int COMPONENTS, bool USE_YUV>
 469 void ThresholdUnit::render_data(LoadPackage *package)
 470 {
 471         const ThresholdPackage *pkg = (ThresholdPackage*)package;
 472         const ThresholdConfig *config = & server->plugin->config;
 473         VFrame *data = server->data;
 474         const int min = (int)(config->min * 0xffff);
 475         const int max = (int)(config->max * 0xffff);
 476         const int w = data->get_w();
 477         //const int h = data->get_h();
 478
 479         const TYPE r_low = scale_to_range<TYPE>(config->low_color.r);
 480         const TYPE g_low = scale_to_range<TYPE>(config->low_color.g);
 481         const TYPE b_low = scale_to_range<TYPE>(config->low_color.b);
 482         const TYPE a_low = scale_to_range<TYPE>(config->low_color.a);
 483
 484         const TYPE r_mid = scale_to_range<TYPE>(config->mid_color.r);
 485         const TYPE g_mid = scale_to_range<TYPE>(config->mid_color.g);
 486         const TYPE b_mid = scale_to_range<TYPE>(config->mid_color.b);
 487         const TYPE a_mid = scale_to_range<TYPE>(config->mid_color.a);
 488
 489         const TYPE r_high = scale_to_range<TYPE>(config->high_color.r);
 490         const TYPE g_high = scale_to_range<TYPE>(config->high_color.g);
 491         const TYPE b_high = scale_to_range<TYPE>(config->high_color.b);
 492         const TYPE a_high = scale_to_range<TYPE>(config->high_color.a);
 493
 494         TYPE y_low,  u_low,  v_low;
 495         TYPE y_mid,  u_mid,  v_mid;
 496         TYPE y_high, u_high, v_high;
 497
 498         if (USE_YUV)
 499         {
 500                 rgb_to_yuv(r_low,  g_low,  b_low,  y_low,  u_low,  v_low);
 501                 rgb_to_yuv(r_mid,  g_mid,  b_mid,  y_mid,  u_mid,  v_mid);
 502                 rgb_to_yuv(r_high, g_high, b_high, y_high, u_high, v_high);
 503         }
 504
 505         for(int i = pkg->start; i < pkg->end; i++)
 506         {
 507                 TYPE *in_row = (TYPE*)data->get_rows()[i];
 508                 TYPE *out_row = in_row;
 509                 for(int j = 0; j < w; j++)
 510                 {
 511                         if (USE_YUV)
 512                         {
 513                                 const int y = get_component(in_row[0]);
 514                                 if (y < min)
 515                                 {
 516                                         *out_row++ = y_low;
 517                                         *out_row++ = u_low;
 518                                         *out_row++ = v_low;
 519                                         if(COMPONENTS == 4) *out_row++ = a_low;
 520                                 }
 521                                 else if (y < max)
 522                                 {
 523                                         *out_row++ = y_mid;
 524                                         *out_row++ = u_mid;
 525                                         *out_row++ = v_mid;
 526                                         if(COMPONENTS == 4) *out_row++ = a_mid;
 527                                 }
 528                                 else
 529                                 {
 530                                         *out_row++ = y_high;
 531                                         *out_row++ = u_high;
 532                                         *out_row++ = v_high;
 533                                         if(COMPONENTS == 4) *out_row++ = a_high;
 534                                 }
 535                         }
 536                         else
 537                         {
 538                                 const int r = get_component(in_row[0]);
 539                                 const int g = get_component(in_row[1]);
 540                                 const int b = get_component(in_row[2]);
 541                                 const int y = (r * 76 + g * 150 + b * 29) >> 8;
 542                                 if (y < min)
 543                                 {
 544                                         *out_row++ = r_low;
 545                                         *out_row++ = g_low;
 546                                         *out_row++ = b_low;
 547                                         if(COMPONENTS == 4) *out_row++ = a_low;
 548                                 }
 549                                 else if (y < max)
 550                                 {
 551                                         *out_row++ = r_mid;
 552                                         *out_row++ = g_mid;
 553                                         *out_row++ = b_mid;
 554                                         if(COMPONENTS == 4) *out_row++ = a_mid;
 555                                 }
 556                                 else
 557                                 {
 558                                         *out_row++ = r_high;
 559                                         *out_row++ = g_high;
 560                                         *out_row++ = b_high;
 561                                         if(COMPONENTS == 4) *out_row++ = a_high;
 562                                 }
 563                         }
 564                         in_row += COMPONENTS;
 565                 }
 566         }
 567 }
 568
 569 void ThresholdUnit::process_package(LoadPackage *package)
 570 {
 571         switch(server->data->get_color_model())
 572         {
 573                 case BC_RGB888:
 574                         render_data<unsigned char, 3, false>(package);
 575                         break;
 576
 577                 case BC_RGB_FLOAT:
 578                         render_data<float, 3, false>(package);
 579                         break;
 580
 581                 case BC_RGBA8888:
 582                         render_data<unsigned char, 4, false>(package);
 583                         break;
 584
 585                 case BC_RGBA_FLOAT:
 586                         render_data<float, 4, false>(package);
 587                         break;
 588
 589                 case BC_YUV888:
 590                         render_data<unsigned char, 3, true>(package);
 591                         break;
 592
 593                 case BC_YUVA8888:
 594                         render_data<unsigned char, 4, true>(package);
 595                         break;
 596
 597                 case BC_YUV161616:
 598                         render_data<uint16_t, 3, true>(package);
 599                         break;
 600
 601                 case BC_YUVA16161616:
 602                         render_data<uint16_t, 4, true>(package);
 603                         break;
 604         }
 605 }
 606
 607
 608
 609
 610
 611
 612
 613
 614
 615
 616
 617 ThresholdEngine::ThresholdEngine(ThresholdMain *plugin)
 618  : LoadServer(plugin->get_project_smp() + 1,
 619         plugin->get_project_smp() + 1)
 620 {
 621         this->plugin = plugin;
 622 }
 623
 624 ThresholdEngine::~ThresholdEngine()
 625 {
 626 }
 627
 628 void ThresholdEngine::process_packages(VFrame *data)
 629 {
 630         this->data = data;
 631         LoadServer::process_packages();
 632 }
 633
 634 void ThresholdEngine::init_packages()
 635 {
 636         for(int i = 0; i < get_total_packages(); i++)
 637         {
 638                 ThresholdPackage *package = (ThresholdPackage*)get_package(i);
 639                 package->start = data->get_h() * i / get_total_packages();
 640                 package->end = data->get_h() * (i + 1) / get_total_packages();
 641         }
 642 }
 643
 644 LoadClient* ThresholdEngine::new_client()
 645 {
 646         return (LoadClient*)new ThresholdUnit(this);
 647 }
 648
 649 LoadPackage* ThresholdEngine::new_package()
 650 {
 651         return (LoadPackage*)new HistogramPackage;
 652 }
 653
 654
 655
 656
 657
 658
 659
 660
 661 RGBA::RGBA()
 662 {
 663         r = g = b = a = 0;
 664 }
 665
 666 RGBA::RGBA(int r, int g, int b, int a)
 667 {
 668         this->r = r;
 669         this->g = g;
 670         this->b = b;
 671         this->a = a;
 672 }
 673
 674 void RGBA::set(int r, int g, int b, int a)
 675 {
 676         this->r = r;
 677         this->g = g;
 678         this->b = b;
 679         this->a = a;
 680 }
 681
 682 void RGBA::set(int rgb, int alpha)
 683 {
 684         r = (rgb & 0xff0000) >> 16;
 685         g = (rgb & 0xff00)   >>  8;
 686         b = (rgb & 0xff);
 687         a = alpha;
 688 }
 689
 690 int RGBA::getRGB() const
 691 {
 692         return r << 16 | g << 8 | b;
 693 }
 694
 695 static void init_RGBA_keys(const char * prefix,
 696                            string & r_s,
 697                            string & g_s,
 698                            string & b_s,
 699                            string & a_s)
 700 {
 701         r_s = prefix;
 702         g_s = prefix;
 703         b_s = prefix;
 704         a_s = prefix;
 705
 706         r_s += "_R";
 707         g_s += "_G";
 708         b_s += "_B";
 709         a_s += "_A";
 710 }
 711
 712 void RGBA::set_property(XMLTag & tag, const char * prefix) const
 713 {
 714         string r_s, g_s, b_s, a_s;
 715         init_RGBA_keys(prefix, r_s, g_s, b_s, a_s);
 716
 717         tag.set_property(const_cast<char *>(r_s.c_str()), r);
 718         tag.set_property(const_cast<char *>(g_s.c_str()), g);
 719         tag.set_property(const_cast<char *>(b_s.c_str()), b);
 720         tag.set_property(const_cast<char *>(a_s.c_str()), a);
 721 }
 722
 723 RGBA RGBA::get_property(XMLTag & tag, const char * prefix) const
 724 {
 725         string r_s, g_s, b_s, a_s;
 726         init_RGBA_keys(prefix, r_s, g_s, b_s, a_s);
 727
 728         return RGBA(tag.get_property(const_cast<char *>(r_s.c_str()), r),
 729                     tag.get_property(const_cast<char *>(g_s.c_str()), g),
 730                     tag.get_property(const_cast<char *>(b_s.c_str()), b),
 731                     tag.get_property(const_cast<char *>(a_s.c_str()), a));
 732 }
 733
 734 bool operator==(const RGBA & a, const RGBA & b)
 735 {
 736         return  a.r == b.r &&
 737                 a.g == b.g &&
 738                 a.b == b.b &&
 739                 a.a == b.a;
 740 }
 741
 742 template<>
 743 RGBA interpolate(const RGBA & prev_color, const double & prev_scale, const RGBA &next_color, const double & next_scale)
 744 {
 745         return RGBA(interpolate(prev_color.r, prev_scale, next_color.r, next_scale),
 746                     interpolate(prev_color.g, prev_scale, next_color.g, next_scale),
 747                     interpolate(prev_color.b, prev_scale, next_color.b, next_scale),
 748                     interpolate(prev_color.a, prev_scale, next_color.a, next_scale));
 749 }