git.sesse.net Git - vlc/blob - modules/video_filter/gradient.c

   1 /*****************************************************************************
   2  * gradient.c : Gradient and edge detection video effects plugin for vlc
   3  *****************************************************************************
   4  * Copyright (C) 2000-2008 the VideoLAN team
   5  * $Id$
   6  *
   7  * Authors: Samuel Hocevar <sam@zoy.org>
   8  *          Antoine Cellerier <dionoea -at- videolan -dot- org>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program 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
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  23  *****************************************************************************/
  24
  25 /*****************************************************************************
  26  * Preamble
  27  *****************************************************************************/
  28
  29 #include <math.h>                                            /* sin(), cos() */
  30
  31 #ifdef HAVE_CONFIG_H
  32 # include "config.h"
  33 #endif
  34
  35 #include <vlc_common.h>
  36 #include <vlc_plugin.h>
  37 #include <vlc_sout.h>
  38 #include <vlc_vout.h>
  39
  40 #include "vlc_filter.h"
  41 #include "filter_picture.h"
  42
  43 enum { GRADIENT, EDGE, HOUGH };
  44
  45 /*****************************************************************************
  46  * Local prototypes
  47  *****************************************************************************/
  48 static int  Create    ( vlc_object_t * );
  49 static void Destroy   ( vlc_object_t * );
  50
  51 static picture_t *Filter( filter_t *, picture_t * );
  52 static int GradientCallback( vlc_object_t *, char const *,
  53                              vlc_value_t, vlc_value_t,
  54                              void * );
  55
  56 static void FilterGradient( filter_t *, picture_t *, picture_t * );
  57 static void FilterEdge    ( filter_t *, picture_t *, picture_t * );
  58 static void FilterHough   ( filter_t *, picture_t *, picture_t * );
  59
  60 /*****************************************************************************
  61  * Module descriptor
  62  *****************************************************************************/
  63 #define MODE_TEXT N_("Distort mode")
  64 #define MODE_LONGTEXT N_("Distort mode, one of \"gradient\", \"edge\" and \"hough\".")
  65
  66 #define GRADIENT_TEXT N_("Gradient image type")
  67 #define GRADIENT_LONGTEXT N_("Gradient image type (0 or 1). 0 will " \
  68         "turn the image to white while 1 will keep colors." )
  69
  70 #define CARTOON_TEXT N_("Apply cartoon effect")
  71 #define CARTOON_LONGTEXT N_("Apply cartoon effect. It is only used by " \
  72     "\"gradient\" and \"edge\".")
  73
  74 static const char *const mode_list[] = { "gradient", "edge", "hough" };
  75 static const char *const mode_list_text[] = { N_("Gradient"), N_("Edge"), N_("Hough") };
  76
  77 #define FILTER_PREFIX "gradient-"
  78
  79 vlc_module_begin();
  80     set_description( N_("Gradient video filter") );
  81     set_shortname( N_( "Gradient" ));
  82     set_capability( "video filter2", 0 );
  83     set_category( CAT_VIDEO );
  84     set_subcategory( SUBCAT_VIDEO_VFILTER );
  85
  86     add_string( FILTER_PREFIX "mode", "gradient", NULL,
  87                 MODE_TEXT, MODE_LONGTEXT, false );
  88         change_string_list( mode_list, mode_list_text, 0 );
  89
  90     add_integer_with_range( FILTER_PREFIX "type", 0, 0, 1, NULL,
  91                 GRADIENT_TEXT, GRADIENT_LONGTEXT, false );
  92     add_bool( FILTER_PREFIX "cartoon", 1, NULL,
  93                 CARTOON_TEXT, CARTOON_LONGTEXT, false );
  94
  95     add_shortcut( "gradient" );
  96     set_callbacks( Create, Destroy );
  97 vlc_module_end();
  98
  99 static const char *const ppsz_filter_options[] = {
 100     "mode", "type", "cartoon", NULL
 101 };
 102
 103 /*****************************************************************************
 104  * vout_sys_t: Distort video output method descriptor
 105  *****************************************************************************
 106  * This structure is part of the video output thread descriptor.
 107  * It describes the Distort specific properties of an output thread.
 108  *****************************************************************************/
 109 struct filter_sys_t
 110 {
 111     int i_mode;
 112
 113     /* For the gradient mode */
 114     int i_gradient_type;
 115     bool b_cartoon;
 116
 117     uint32_t *p_buf32;
 118     uint32_t *p_buf32_bis;
 119     uint8_t *p_buf8;
 120
 121     /* For hough mode */
 122     int *p_pre_hough;
 123 };
 124
 125 /*****************************************************************************
 126  * Create: allocates Distort video thread output method
 127  *****************************************************************************
 128  * This function allocates and initializes a Distort vout method.
 129  *****************************************************************************/
 130 static int Create( vlc_object_t *p_this )
 131 {
 132     filter_t *p_filter = (filter_t *)p_this;
 133     char *psz_method;
 134
 135     switch( p_filter->fmt_in.video.i_chroma )
 136     {
 137         CASE_PLANAR_YUV
 138             break;
 139
 140         default:
 141              msg_Err( p_filter, "Unsupported input chroma (%4s)",
 142                       (char*)&(p_filter->fmt_in.video.i_chroma) );
 143             return VLC_EGENERIC;
 144     }
 145
 146     /* Allocate structure */
 147     p_filter->p_sys = malloc( sizeof( filter_sys_t ) );
 148     if( p_filter->p_sys == NULL )
 149     {
 150         msg_Err( p_filter, "out of memory" );
 151         return VLC_ENOMEM;
 152     }
 153
 154     p_filter->pf_video_filter = Filter;
 155
 156     p_filter->p_sys->p_pre_hough = NULL;
 157
 158     config_ChainParse( p_filter, FILTER_PREFIX, ppsz_filter_options,
 159                    p_filter->p_cfg );
 160
 161     if( !(psz_method =
 162         var_CreateGetNonEmptyStringCommand( p_filter, FILTER_PREFIX "mode" )) )
 163     {
 164         msg_Err( p_filter, "configuration variable "
 165                  FILTER_PREFIX "mode empty" );
 166         p_filter->p_sys->i_mode = GRADIENT;
 167     }
 168     else
 169     {
 170         if( !strcmp( psz_method, "gradient" ) )
 171         {
 172             p_filter->p_sys->i_mode = GRADIENT;
 173         }
 174         else if( !strcmp( psz_method, "edge" ) )
 175         {
 176             p_filter->p_sys->i_mode = EDGE;
 177         }
 178         else if( !strcmp( psz_method, "hough" ) )
 179         {
 180             p_filter->p_sys->i_mode = HOUGH;
 181         }
 182         else
 183         {
 184             msg_Err( p_filter, "no valid gradient mode provided (%s)", psz_method );
 185             p_filter->p_sys->i_mode = GRADIENT;
 186         }
 187     }
 188     free( psz_method );
 189
 190     p_filter->p_sys->i_gradient_type =
 191         var_CreateGetIntegerCommand( p_filter, FILTER_PREFIX "type" );
 192     p_filter->p_sys->b_cartoon =
 193         var_CreateGetBoolCommand( p_filter, FILTER_PREFIX "cartoon" );
 194
 195     var_AddCallback( p_filter, FILTER_PREFIX "mode",
 196                      GradientCallback, p_filter->p_sys );
 197     var_AddCallback( p_filter, FILTER_PREFIX "type",
 198                      GradientCallback, p_filter->p_sys );
 199     var_AddCallback( p_filter, FILTER_PREFIX "cartoon",
 200                      GradientCallback, p_filter->p_sys );
 201
 202     p_filter->p_sys->p_buf32 = NULL;
 203     p_filter->p_sys->p_buf32_bis = NULL;
 204     p_filter->p_sys->p_buf8 = NULL;
 205
 206     return VLC_SUCCESS;
 207 }
 208
 209 /*****************************************************************************
 210  * Destroy: destroy Distort video thread output method
 211  *****************************************************************************
 212  * Terminate an output method created by DistortCreateOutputMethod
 213  *****************************************************************************/
 214 static void Destroy( vlc_object_t *p_this )
 215 {
 216     filter_t *p_filter = (filter_t *)p_this;
 217
 218     free( p_filter->p_sys->p_buf32 );
 219     free( p_filter->p_sys->p_buf32_bis );
 220     free( p_filter->p_sys->p_buf8 );
 221     free( p_filter->p_sys->p_pre_hough );
 222
 223     free( p_filter->p_sys );
 224 }
 225
 226 /*****************************************************************************
 227  * Render: displays previously rendered output
 228  *****************************************************************************
 229  * This function send the currently rendered image to Distort image, waits
 230  * until it is displayed and switch the two rendering buffers, preparing next
 231  * frame.
 232  *****************************************************************************/
 233 static picture_t *Filter( filter_t *p_filter, picture_t *p_pic )
 234 {
 235     picture_t *p_outpic;
 236
 237     if( !p_pic ) return NULL;
 238
 239     p_outpic = p_filter->pf_vout_buffer_new( p_filter );
 240     if( !p_outpic )
 241     {
 242         msg_Warn( p_filter, "can't get output picture" );
 243         if( p_pic->pf_release )
 244             p_pic->pf_release( p_pic );
 245         return NULL;
 246     }
 247
 248     switch( p_filter->p_sys->i_mode )
 249     {
 250         case EDGE:
 251             FilterEdge( p_filter, p_pic, p_outpic );
 252             break;
 253
 254         case GRADIENT:
 255             FilterGradient( p_filter, p_pic, p_outpic );
 256             break;
 257
 258         case HOUGH:
 259             FilterHough( p_filter, p_pic, p_outpic );
 260             break;
 261
 262         default:
 263             break;
 264     }
 265
 266     return CopyInfoAndRelease( p_outpic, p_pic );
 267 }
 268
 269 /*****************************************************************************
 270  * Gaussian Convolution
 271  *****************************************************************************
 272  *    Gaussian convolution ( sigma == 1.4 )
 273  *
 274  *    |  2  4  5  4  2  |   |  2  4  4  4  2 |
 275  *    |  4  9 12  9  4  |   |  4  8 12  8  4 |
 276  *    |  5 12 15 12  5  | ~ |  4 12 16 12  4 |
 277  *    |  4  9 12  9  4  |   |  4  8 12  8  4 |
 278  *    |  2  4  5  4  2  |   |  2  4  4  4  2 |
 279  *****************************************************************************/
 280 static void GaussianConvolution( picture_t *p_inpic, uint32_t *p_smooth )
 281 {
 282     const uint8_t *p_inpix = p_inpic->p[Y_PLANE].p_pixels;
 283     const int i_src_pitch = p_inpic->p[Y_PLANE].i_pitch;
 284     const int i_src_visible = p_inpic->p[Y_PLANE].i_visible_pitch;
 285     const int i_num_lines = p_inpic->p[Y_PLANE].i_visible_lines;
 286
 287     int x,y;
 288     for( y = 2; y < i_num_lines - 2; y++ )
 289     {
 290         for( x = 2; x < i_src_visible - 2; x++ )
 291         {
 292             p_smooth[y*i_src_visible+x] = (uint32_t)(
 293               /* 2 rows up */
 294                 ( p_inpix[(y-2)*i_src_pitch+x-2] )
 295               + ((p_inpix[(y-2)*i_src_pitch+x-1]
 296               +   p_inpix[(y-2)*i_src_pitch+x]
 297               +   p_inpix[(y-2)*i_src_pitch+x+1])<<1 )
 298               + ( p_inpix[(y-2)*i_src_pitch+x+2] )
 299               /* 1 row up */
 300               + ((p_inpix[(y-1)*i_src_pitch+x-2]
 301               + ( p_inpix[(y-1)*i_src_pitch+x-1]<<1 )
 302               + ( p_inpix[(y-1)*i_src_pitch+x]*3 )
 303               + ( p_inpix[(y-1)*i_src_pitch+x+1]<<1 )
 304               +   p_inpix[(y-1)*i_src_pitch+x+2]
 305               /* */
 306               +   p_inpix[y*i_src_pitch+x-2]
 307               + ( p_inpix[y*i_src_pitch+x-1]*3 )
 308               + ( p_inpix[y*i_src_pitch+x]<<2 )
 309               + ( p_inpix[y*i_src_pitch+x+1]*3 )
 310               +   p_inpix[y*i_src_pitch+x+2]
 311               /* 1 row down */
 312               +   p_inpix[(y+1)*i_src_pitch+x-2]
 313               + ( p_inpix[(y+1)*i_src_pitch+x-1]<<1 )
 314               + ( p_inpix[(y+1)*i_src_pitch+x]*3 )
 315               + ( p_inpix[(y+1)*i_src_pitch+x+1]<<1 )
 316               +   p_inpix[(y+1)*i_src_pitch+x+2] )<<1 )
 317               /* 2 rows down */
 318               + ( p_inpix[(y+2)*i_src_pitch+x-2] )
 319               + ((p_inpix[(y+2)*i_src_pitch+x-1]
 320               +   p_inpix[(y+2)*i_src_pitch+x]
 321               +   p_inpix[(y+2)*i_src_pitch+x+1])<<1 )
 322               + ( p_inpix[(y+2)*i_src_pitch+x+2] )
 323               ) >> 6 /* 115 */;
 324         }
 325     }
 326 }
 327
 328 /*****************************************************************************
 329  * FilterGradient: Sobel
 330  *****************************************************************************/
 331 static void FilterGradient( filter_t *p_filter, picture_t *p_inpic,
 332                                                 picture_t *p_outpic )
 333 {
 334     int x, y;
 335     const int i_src_pitch = p_inpic->p[Y_PLANE].i_pitch;
 336     const int i_src_visible = p_inpic->p[Y_PLANE].i_visible_pitch;
 337     const int i_dst_pitch = p_outpic->p[Y_PLANE].i_pitch;
 338     const int i_num_lines = p_inpic->p[Y_PLANE].i_visible_lines;
 339
 340     const uint8_t *p_inpix = p_inpic->p[Y_PLANE].p_pixels;
 341     uint8_t *p_outpix = p_outpic->p[Y_PLANE].p_pixels;
 342
 343     uint32_t *p_smooth;
 344     if( !p_filter->p_sys->p_buf32 )
 345         p_filter->p_sys->p_buf32 =
 346         (uint32_t *)malloc( i_num_lines * i_src_visible * sizeof(uint32_t));
 347     p_smooth = p_filter->p_sys->p_buf32;
 348
 349     if( !p_smooth ) return;
 350
 351     if( p_filter->p_sys->b_cartoon )
 352     {
 353         vlc_memcpy( p_outpic->p[U_PLANE].p_pixels,
 354             p_inpic->p[U_PLANE].p_pixels,
 355             p_outpic->p[U_PLANE].i_lines * p_outpic->p[U_PLANE].i_pitch );
 356         vlc_memcpy( p_outpic->p[V_PLANE].p_pixels,
 357             p_inpic->p[V_PLANE].p_pixels,
 358             p_outpic->p[V_PLANE].i_lines * p_outpic->p[V_PLANE].i_pitch );
 359     }
 360     else
 361     {
 362         vlc_memset( p_outpic->p[U_PLANE].p_pixels, 0x80,
 363             p_outpic->p[U_PLANE].i_lines * p_outpic->p[U_PLANE].i_pitch );
 364         vlc_memset( p_outpic->p[V_PLANE].p_pixels, 0x80,
 365             p_outpic->p[V_PLANE].i_lines * p_outpic->p[V_PLANE].i_pitch );
 366     }
 367
 368     GaussianConvolution( p_inpic, p_smooth );
 369
 370     /* Sobel gradient
 371
 372      | -1 0 1 |     |  1  2  1 |
 373      | -2 0 2 | and |  0  0  0 |
 374      | -1 0 1 |     | -1 -2 -1 | */
 375
 376 #define FOR                                                     \
 377     for( y = 1; y < i_num_lines - 1; y++ )                      \
 378     {                                                           \
 379         for( x = 1; x < i_src_visible - 1; x++ )                \
 380         {                                                       \
 381             const uint32_t a =                                  \
 382             (                                                   \
 383               abs(                                              \
 384                  ( p_smooth[(y-1)*i_src_visible+x-1]            \
 385                    - p_smooth[(y+1)*i_src_visible+x-1] )        \
 386                + ( ( p_smooth[(y-1)*i_src_visible+x]            \
 387                     - p_smooth[(y+1)*i_src_visible+x] ) <<1 )   \
 388                + ( p_smooth[(y-1)*i_src_visible+x+1]            \
 389                    - p_smooth[(y+1)*i_src_visible+x+1] )        \
 390               )                                                 \
 391             +                                                   \
 392               abs(                                              \
 393                  ( p_smooth[(y-1)*i_src_visible+x-1]            \
 394                    - p_smooth[(y-1)*i_src_visible+x+1] )        \
 395                + ( ( p_smooth[y*i_src_visible+x-1]              \
 396                     - p_smooth[y*i_src_visible+x+1] ) <<1 )     \
 397                + ( p_smooth[(y+1)*i_src_visible+x-1]            \
 398                    - p_smooth[(y+1)*i_src_visible+x+1] )        \
 399               )                                                 \
 400             );
 401     if( p_filter->p_sys->i_gradient_type )
 402     {
 403         if( p_filter->p_sys->b_cartoon )
 404         {
 405             FOR
 406             if( a > 60 )
 407             {
 408                 p_outpix[y*i_dst_pitch+x] = 0x00;
 409             }
 410             else
 411             {
 412                 if( p_smooth[y*i_src_visible+x] > 0xa0 )
 413                     p_outpix[y*i_dst_pitch+x] =
 414                         0xff - ((0xff - p_inpix[y*i_src_pitch+x] )>>2);
 415                 else if( p_smooth[y*i_src_visible+x] > 0x70 )
 416                     p_outpix[y*i_dst_pitch+x] =
 417                         0xa0 - ((0xa0 - p_inpix[y*i_src_pitch+x] )>>2);
 418                 else if( p_smooth[y*i_src_visible+x] > 0x28 )
 419                     p_outpix[y*i_dst_pitch+x] =
 420                         0x70 - ((0x70 - p_inpix[y*i_src_pitch+x] )>>2);
 421                 else
 422                     p_outpix[y*i_dst_pitch+x] =
 423                         0x28 - ((0x28 - p_inpix[y*i_src_pitch+x] )>>2);
 424             }
 425             }}
 426         }
 427         else
 428         {
 429             FOR
 430             p_outpix[y*i_dst_pitch+x] = clip_uint8_vlc( a );
 431             }}
 432         }
 433     }
 434     else
 435     {
 436         FOR
 437         if( a>>8 )
 438             p_outpix[y*i_dst_pitch+x] = 0;
 439         else
 440             p_outpix[y*i_dst_pitch+x] = 0xff-(uint8_t)a;
 441         }}
 442     }
 443 #undef FOR
 444 }
 445
 446 /*****************************************************************************
 447  * FilterEdge: Canny edge detection algorithm
 448  *****************************************************************************
 449  * http://fourier.eng.hmc.edu/e161/lectures/canny/node1.html
 450  * (well ... my implementation isn't really the canny algorithm ... but some
 451  * ideas are the same)
 452  *****************************************************************************/
 453 /* angle : | */
 454 #define THETA_Y 0
 455 /* angle : - */
 456 #define THETA_X 1
 457 /* angle : / */
 458 #define THETA_P 2
 459 /* angle : \ */
 460 #define THETA_M 3
 461 static void FilterEdge( filter_t *p_filter, picture_t *p_inpic,
 462                                             picture_t *p_outpic )
 463 {
 464     int x, y;
 465
 466     const int i_src_pitch = p_inpic->p[Y_PLANE].i_pitch;
 467     const int i_src_visible = p_inpic->p[Y_PLANE].i_visible_pitch;
 468     const int i_dst_pitch = p_outpic->p[Y_PLANE].i_pitch;
 469     const int i_num_lines = p_inpic->p[Y_PLANE].i_visible_lines;
 470
 471     const uint8_t *p_inpix = p_inpic->p[Y_PLANE].p_pixels;
 472     uint8_t *p_outpix = p_outpic->p[Y_PLANE].p_pixels;
 473
 474     uint32_t *p_smooth;
 475     uint32_t *p_grad;
 476     uint8_t *p_theta;
 477
 478     if( !p_filter->p_sys->p_buf32 )
 479         p_filter->p_sys->p_buf32 =
 480         (uint32_t *)malloc( i_num_lines * i_src_visible * sizeof(uint32_t));
 481     p_smooth = p_filter->p_sys->p_buf32;
 482
 483     if( !p_filter->p_sys->p_buf32_bis )
 484         p_filter->p_sys->p_buf32_bis =
 485         (uint32_t *)malloc( i_num_lines * i_src_visible * sizeof(uint32_t));
 486     p_grad = p_filter->p_sys->p_buf32_bis;
 487
 488     if( !p_filter->p_sys->p_buf8 )
 489         p_filter->p_sys->p_buf8 =
 490         (uint8_t *)malloc( i_num_lines * i_src_visible * sizeof(uint8_t));
 491     p_theta = p_filter->p_sys->p_buf8;
 492
 493     if( !p_smooth || !p_grad || !p_theta ) return;
 494
 495     if( p_filter->p_sys->b_cartoon )
 496     {
 497         vlc_memcpy( p_outpic->p[U_PLANE].p_pixels,
 498             p_inpic->p[U_PLANE].p_pixels,
 499             p_outpic->p[U_PLANE].i_lines * p_outpic->p[U_PLANE].i_pitch );
 500         vlc_memcpy( p_outpic->p[V_PLANE].p_pixels,
 501             p_inpic->p[V_PLANE].p_pixels,
 502             p_outpic->p[V_PLANE].i_lines * p_outpic->p[V_PLANE].i_pitch );
 503     }
 504     else
 505     {
 506         vlc_memset( p_outpic->p[Y_PLANE].p_pixels, 0xff,
 507               p_outpic->p[Y_PLANE].i_lines * p_outpic->p[Y_PLANE].i_pitch );
 508         vlc_memset( p_outpic->p[U_PLANE].p_pixels, 0x80,
 509             p_outpic->p[U_PLANE].i_lines * p_outpic->p[U_PLANE].i_pitch );
 510         vlc_memset( p_outpic->p[V_PLANE].p_pixels, 0x80,
 511             p_outpic->p[V_PLANE].i_lines * p_outpic->p[V_PLANE].i_pitch );
 512     }
 513
 514     GaussianConvolution( p_inpic, p_smooth );
 515
 516     /* Sobel gradient
 517
 518      | -1 0 1 |     |  1  2  1 |
 519      | -2 0 2 | and |  0  0  0 |
 520      | -1 0 1 |     | -1 -2 -1 | */
 521
 522     for( y = 1; y < i_num_lines - 1; y++ )
 523     {
 524         for( x = 1; x < i_src_visible - 1; x++ )
 525         {
 526
 527             const int gradx =
 528                  ( p_smooth[(y-1)*i_src_visible+x-1]
 529                    - p_smooth[(y+1)*i_src_visible+x-1] )
 530                + ( ( p_smooth[(y-1)*i_src_visible+x]
 531                     - p_smooth[(y+1)*i_src_visible+x] ) <<1 )
 532                + ( p_smooth[(y-1)*i_src_visible+x+1]
 533                    - p_smooth[(y+1)*i_src_visible+x+1] );
 534             const int grady =
 535                  ( p_smooth[(y-1)*i_src_visible+x-1]
 536                    - p_smooth[(y-1)*i_src_visible+x+1] )
 537                + ( ( p_smooth[y*i_src_visible+x-1]
 538                     - p_smooth[y*i_src_visible+x+1] ) <<1 )
 539                + ( p_smooth[(y+1)*i_src_visible+x-1]
 540                    - p_smooth[(y+1)*i_src_visible+x+1] );
 541
 542             p_grad[y*i_src_visible+x] = (uint32_t)(abs( gradx ) + abs( grady ));
 543
 544             /* tan( 22.5 ) = 0,414213562 .. * 128 = 53
 545              * tan( 26,565051177 ) = 0.5
 546              * tan( 45 + 22.5 ) = 2,414213562 .. * 128 = 309
 547              * tan( 63,434948823 ) 2 */
 548             if( (grady<<1) > gradx )
 549                 p_theta[y*i_src_visible+x] = THETA_P;
 550             else if( (grady<<1) < -gradx )
 551                 p_theta[y*i_src_visible+x] = THETA_M;
 552             else if( !gradx || abs(grady) > abs(gradx)<<1 )
 553                 p_theta[y*i_src_visible+x] = THETA_Y;
 554             else
 555                 p_theta[y*i_src_visible+x] = THETA_X;
 556         }
 557     }
 558
 559     /* edge computing */
 560     for( y = 1; y < i_num_lines - 1; y++ )
 561     {
 562         for( x = 1; x < i_src_visible - 1; x++ )
 563         {
 564             if( p_grad[y*i_src_visible+x] > 40 )
 565             {
 566                 switch( p_theta[y*i_src_visible+x] )
 567                 {
 568                     case THETA_Y:
 569                         if(    p_grad[y*i_src_visible+x] > p_grad[(y-1)*i_src_visible+x]
 570                             && p_grad[y*i_src_visible+x] > p_grad[(y+1)*i_src_visible+x] )
 571                         {
 572                             p_outpix[y*i_dst_pitch+x] = 0;
 573                             break;
 574                         } else goto colorize;
 575                     case THETA_P:
 576                         if(    p_grad[y*i_src_visible+x] > p_grad[(y-1)*i_src_visible+x-1]
 577                             && p_grad[y*i_src_visible+x] > p_grad[(y+1)*i_src_visible+x+1] )
 578                         {
 579                             p_outpix[y*i_dst_pitch+x] = 0;
 580                             break;
 581                         } else goto colorize;
 582                     case THETA_M:
 583                         if(    p_grad[y*i_src_visible+x] > p_grad[(y-1)*i_src_visible+x+1]
 584                             && p_grad[y*i_src_visible+x] > p_grad[(y+1)*i_src_visible+x-1] )
 585                         {
 586                             p_outpix[y*i_dst_pitch+x] = 0;
 587                             break;
 588                         } else goto colorize;
 589                     case THETA_X:
 590                         if(    p_grad[y*i_src_visible+x] > p_grad[y*i_src_visible+x-1]
 591                             && p_grad[y*i_src_visible+x] > p_grad[y*i_src_visible+x+1] )
 592                         {
 593                             p_outpix[y*i_dst_pitch+x] = 0;
 594                             break;
 595                         } else goto colorize;
 596                 }
 597             }
 598             else
 599             {
 600                 colorize:
 601                 if( p_filter->p_sys->b_cartoon )
 602                 {
 603                     if( p_smooth[y*i_src_visible+x] > 0xa0 )
 604                         p_outpix[y*i_dst_pitch+x] = (uint8_t)
 605                             0xff - ((0xff - p_inpix[y*i_src_pitch+x] )>>2);
 606                     else if( p_smooth[y*i_src_visible+x] > 0x70 )
 607                         p_outpix[y*i_dst_pitch+x] =(uint8_t)
 608                             0xa0 - ((0xa0 - p_inpix[y*i_src_pitch+x] )>>2);
 609                     else if( p_smooth[y*i_src_visible+x] > 0x28 )
 610                         p_outpix[y*i_dst_pitch+x] =(uint8_t)
 611                             0x70 - ((0x70 - p_inpix[y*i_src_pitch+x] )>>2);
 612                     else
 613                         p_outpix[y*i_dst_pitch+x] =(uint8_t)
 614                             0x28 - ((0x28 - p_inpix[y*i_src_pitch+x] )>>2);
 615                 }
 616             }
 617         }
 618     }
 619 }
 620
 621 /*****************************************************************************
 622  * FilterHough
 623  *****************************************************************************/
 624 #define p_pre_hough p_filter->p_sys->p_pre_hough
 625 static void FilterHough( filter_t *p_filter, picture_t *p_inpic,
 626                                              picture_t *p_outpic )
 627 {
 628     int x, y, i;
 629     int i_src_visible = p_inpic->p[Y_PLANE].i_visible_pitch;
 630     int i_dst_pitch = p_outpic->p[Y_PLANE].i_pitch;
 631     int i_num_lines = p_inpic->p[Y_PLANE].i_visible_lines;
 632
 633     uint8_t *p_outpix = p_outpic->p[Y_PLANE].p_pixels;
 634
 635     int i_diag = sqrt( i_num_lines * i_num_lines +
 636                         i_src_visible * i_src_visible);
 637     int i_max, i_phi_max, i_rho, i_rho_max;
 638     int i_nb_steps = 90;
 639     double d_step = M_PI / i_nb_steps;
 640     double d_sin;
 641     double d_cos;
 642     uint32_t *p_smooth;
 643     int *p_hough = malloc( i_diag * i_nb_steps * sizeof(int) );
 644     if( ! p_hough ) return;
 645     p_smooth = (uint32_t *)malloc( i_num_lines*i_src_visible*sizeof(uint32_t));
 646     if( !p_smooth ) return;
 647
 648     if( ! p_pre_hough )
 649     {
 650         msg_Dbg(p_filter, "Starting precalculation");
 651         p_pre_hough = malloc( i_num_lines*i_src_visible*i_nb_steps*sizeof(int));
 652         if( ! p_pre_hough ) return;
 653         for( i = 0 ; i < i_nb_steps ; i++)
 654         {
 655             d_sin = sin(d_step * i);
 656             d_cos = cos(d_step * i);
 657             for( y = 0 ; y < i_num_lines ; y++ )
 658                 for( x = 0 ; x < i_src_visible ; x++ )
 659                 {
 660                     p_pre_hough[(i*i_num_lines+y)*i_src_visible + x] =
 661                         ceil(x*d_sin + y*d_cos);
 662                 }
 663         }
 664         msg_Dbg(p_filter, "Precalculation done");
 665     }
 666
 667     vlc_memset( p_hough, 0, i_diag * i_nb_steps * sizeof(int) );
 668
 669     vlc_memcpy(
 670         p_outpic->p[Y_PLANE].p_pixels, p_inpic->p[Y_PLANE].p_pixels,
 671         p_outpic->p[Y_PLANE].i_lines * p_outpic->p[Y_PLANE].i_pitch );
 672     vlc_memcpy(
 673         p_outpic->p[U_PLANE].p_pixels, p_inpic->p[U_PLANE].p_pixels,
 674         p_outpic->p[U_PLANE].i_lines * p_outpic->p[U_PLANE].i_pitch );
 675     vlc_memcpy(
 676         p_outpic->p[V_PLANE].p_pixels, p_inpic->p[V_PLANE].p_pixels,
 677         p_outpic->p[V_PLANE].i_lines * p_outpic->p[V_PLANE].i_pitch );
 678
 679     GaussianConvolution( p_inpic, p_smooth );
 680
 681     /* Sobel gradient
 682
 683      | -1 0 1 |     |  1  2  1 |
 684      | -2 0 2 | and |  0  0  0 |
 685      | -1 0 1 |     | -1 -2 -1 | */
 686
 687     i_max = 0;
 688     i_rho_max = 0;
 689     i_phi_max = 0;
 690     for( y = 4; y < i_num_lines - 4; y++ )
 691     {
 692         for( x = 4; x < i_src_visible - 4; x++ )
 693         {
 694             uint32_t a =
 695             (
 696               abs(
 697                 ( ( p_smooth[(y-1)*i_src_visible+x]
 698                     - p_smooth[(y+1)*i_src_visible+x] ) <<1 )
 699                + ( p_smooth[(y-1)*i_src_visible+x-1]
 700                    - p_smooth[(y+1)*i_src_visible+x-1] )
 701                + ( p_smooth[(y-1)*i_src_visible+x+1]
 702                    - p_smooth[(y+1)*i_src_visible+x+1] )
 703               )
 704             +
 705               abs(
 706                 ( ( p_smooth[y*i_src_visible+x-1]
 707                     - p_smooth[y*i_src_visible+x+1] ) <<1 )
 708                + ( p_smooth[(y-1)*i_src_visible+x-1]
 709                    - p_smooth[(y-1)*i_src_visible+x+1] )
 710                + ( p_smooth[(y+1)*i_src_visible+x-1]
 711                    - p_smooth[(y+1)*i_src_visible+x+1] )
 712               )
 713             );
 714             if( a>>8 )
 715             {
 716                 for( i = 0 ; i < i_nb_steps ; i ++ )
 717                 {
 718                     i_rho = p_pre_hough[(i*i_num_lines+y)*i_src_visible + x];
 719                     if( p_hough[i_rho + i_diag/2 + i * i_diag]++ > i_max )
 720                     {
 721                         i_max = p_hough[i_rho + i_diag/2 + i * i_diag];
 722                         i_rho_max = i_rho;
 723                         i_phi_max = i;
 724                     }
 725                 }
 726             }
 727         }
 728     }
 729
 730     d_sin = sin(i_phi_max*d_step);
 731     d_cos = cos(i_phi_max*d_step);
 732     if( d_cos != 0 )
 733     {
 734         for( x = 0 ; x < i_src_visible ; x++ )
 735         {
 736             y = (i_rho_max - x * d_sin) / d_cos;
 737             if( y >= 0 && y < i_num_lines )
 738                 p_outpix[y*i_dst_pitch+x] = 255;
 739         }
 740     }
 741
 742     free( p_hough );
 743     free( p_smooth );
 744 }
 745 #undef p_pre_hough
 746
 747
 748 static int GradientCallback( vlc_object_t *p_this, char const *psz_var,
 749                              vlc_value_t oldval, vlc_value_t newval,
 750                              void *p_data )
 751 {
 752     VLC_UNUSED(oldval);
 753     filter_sys_t *p_sys = (filter_sys_t *)p_data;
 754     if( !strcmp( psz_var, FILTER_PREFIX "mode" ) )
 755     {
 756         if( !strcmp( newval.psz_string, "gradient" ) )
 757         {
 758             p_sys->i_mode = GRADIENT;
 759         }
 760         else if( !strcmp( newval.psz_string, "edge" ) )
 761         {
 762             p_sys->i_mode = EDGE;
 763         }
 764         else if( !strcmp( newval.psz_string, "hough" ) )
 765         {
 766             p_sys->i_mode = HOUGH;
 767         }
 768         else
 769         {
 770             msg_Err( p_this, "no valid gradient mode provided (%s)", newval.psz_string );
 771             p_sys->i_mode = GRADIENT;
 772         }
 773     }
 774     else if( !strcmp( psz_var, FILTER_PREFIX "type" ) )
 775     {
 776         p_sys->i_gradient_type = newval.i_int;
 777     }
 778     else if( !strcmp( psz_var, FILTER_PREFIX "cartoon" ) )
 779     {
 780         p_sys->b_cartoon = newval.b_bool;
 781     }
 782     return VLC_SUCCESS;
 783 }