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 #ifdef HAVE_CONFIG_H
  30 # include "config.h"
  31 #endif
  32
  33 #include <math.h>                                            /* sin(), cos() */
  34
  35 #include <vlc_common.h>
  36 #include <vlc_plugin.h>
  37 #include <vlc_sout.h>
  38
  39 #include <vlc_filter.h>
  40 #include "filter_picture.h"
  41
  42 enum { GRADIENT, EDGE, HOUGH };
  43
  44 /*****************************************************************************
  45  * Local prototypes
  46  *****************************************************************************/
  47 static int  Create    ( vlc_object_t * );
  48 static void Destroy   ( vlc_object_t * );
  49
  50 static picture_t *Filter( filter_t *, picture_t * );
  51 static int GradientCallback( vlc_object_t *, char const *,
  52                              vlc_value_t, vlc_value_t,
  53                              void * );
  54
  55 static void FilterGradient( filter_t *, picture_t *, picture_t * );
  56 static void FilterEdge    ( filter_t *, picture_t *, picture_t * );
  57 static void FilterHough   ( filter_t *, picture_t *, picture_t * );
  58
  59 /*****************************************************************************
  60  * Module descriptor
  61  *****************************************************************************/
  62 #define MODE_TEXT N_("Distort mode")
  63 #define MODE_LONGTEXT N_("Distort mode, one of \"gradient\", \"edge\" and \"hough\".")
  64
  65 #define GRADIENT_TEXT N_("Gradient image type")
  66 #define GRADIENT_LONGTEXT N_("Gradient image type (0 or 1). 0 will " \
  67         "turn the image to white while 1 will keep colors." )
  68
  69 #define CARTOON_TEXT N_("Apply cartoon effect")
  70 #define CARTOON_LONGTEXT N_("Apply cartoon effect. It is only used by " \
  71     "\"gradient\" and \"edge\".")
  72
  73 #define GRADIENT_HELP N_("Apply color gradient or edge detection effects")
  74
  75 static const char *const mode_list[] = { "gradient", "edge", "hough" };
  76 static const char *const mode_list_text[] = { N_("Gradient"), N_("Edge"), N_("Hough") };
  77
  78 #define FILTER_PREFIX "gradient-"
  79
  80 vlc_module_begin ()
  81     set_description( N_("Gradient video filter") )
  82     set_shortname( N_( "Gradient" ))
  83     set_help(GRADIENT_HELP)
  84     set_capability( "video filter2", 0 )
  85     set_category( CAT_VIDEO )
  86     set_subcategory( SUBCAT_VIDEO_VFILTER )
  87
  88     add_string( FILTER_PREFIX "mode", "gradient", NULL,
  89                 MODE_TEXT, MODE_LONGTEXT, false )
  90         change_string_list( mode_list, mode_list_text, 0 )
  91
  92     add_integer_with_range( FILTER_PREFIX "type", 0, 0, 1, NULL,
  93                 GRADIENT_TEXT, GRADIENT_LONGTEXT, false )
  94     add_bool( FILTER_PREFIX "cartoon", true, NULL,
  95                 CARTOON_TEXT, CARTOON_LONGTEXT, false )
  96
  97     add_shortcut( "gradient" )
  98     set_callbacks( Create, Destroy )
  99 vlc_module_end ()
 100
 101 static const char *const ppsz_filter_options[] = {
 102     "mode", "type", "cartoon", NULL
 103 };
 104
 105 /*****************************************************************************
 106  * filter_sys_t: Distort video output method descriptor
 107  *****************************************************************************
 108  * This structure is part of the video output thread descriptor.
 109  * It describes the Distort specific properties of an output thread.
 110  *****************************************************************************/
 111 struct filter_sys_t
 112 {
 113     vlc_mutex_t lock;
 114     int i_mode;
 115
 116     /* For the gradient mode */
 117     int i_gradient_type;
 118     bool b_cartoon;
 119
 120     uint32_t *p_buf32;
 121     uint32_t *p_buf32_bis;
 122     uint8_t *p_buf8;
 123
 124     /* For hough mode */
 125     int *p_pre_hough;
 126 };
 127
 128 /*****************************************************************************
 129  * Create: allocates Distort video thread output method
 130  *****************************************************************************
 131  * This function allocates and initializes a Distort vout method.
 132  *****************************************************************************/
 133 static int Create( vlc_object_t *p_this )
 134 {
 135     filter_t *p_filter = (filter_t *)p_this;
 136     char *psz_method;
 137
 138     switch( p_filter->fmt_in.video.i_chroma )
 139     {
 140         CASE_PLANAR_YUV
 141             break;
 142
 143         default:
 144              msg_Err( p_filter, "Unsupported input chroma (%4.4s)",
 145                       (char*)&(p_filter->fmt_in.video.i_chroma) );
 146             return VLC_EGENERIC;
 147     }
 148
 149     /* Allocate structure */
 150     p_filter->p_sys = malloc( sizeof( filter_sys_t ) );
 151     if( p_filter->p_sys == NULL )
 152         return VLC_ENOMEM;
 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     vlc_mutex_init( &p_filter->p_sys->lock );
 196     var_AddCallback( p_filter, FILTER_PREFIX "mode",
 197                      GradientCallback, p_filter->p_sys );
 198     var_AddCallback( p_filter, FILTER_PREFIX "type",
 199                      GradientCallback, p_filter->p_sys );
 200     var_AddCallback( p_filter, FILTER_PREFIX "cartoon",
 201                      GradientCallback, p_filter->p_sys );
 202
 203     p_filter->p_sys->p_buf32 = NULL;
 204     p_filter->p_sys->p_buf32_bis = NULL;
 205     p_filter->p_sys->p_buf8 = NULL;
 206
 207     return VLC_SUCCESS;
 208 }
 209
 210 /*****************************************************************************
 211  * Destroy: destroy Distort video thread output method
 212  *****************************************************************************
 213  * Terminate an output method created by DistortCreateOutputMethod
 214  *****************************************************************************/
 215 static void Destroy( vlc_object_t *p_this )
 216 {
 217     filter_t *p_filter = (filter_t *)p_this;
 218     filter_sys_t *p_sys = p_filter->p_sys;
 219
 220     var_DelCallback( p_filter, FILTER_PREFIX "mode",
 221                      GradientCallback, p_sys );
 222     var_DelCallback( p_filter, FILTER_PREFIX "type",
 223                      GradientCallback, p_sys );
 224     var_DelCallback( p_filter, FILTER_PREFIX "cartoon",
 225                      GradientCallback, p_sys );
 226     vlc_mutex_destroy( &p_sys->lock );
 227
 228     free( p_sys->p_buf32 );
 229     free( p_sys->p_buf32_bis );
 230     free( p_sys->p_buf8 );
 231     free( p_sys->p_pre_hough );
 232
 233     free( p_sys );
 234 }
 235
 236 /*****************************************************************************
 237  * Render: displays previously rendered output
 238  *****************************************************************************
 239  * This function send the currently rendered image to Distort image, waits
 240  * until it is displayed and switch the two rendering buffers, preparing next
 241  * frame.
 242  *****************************************************************************/
 243 static picture_t *Filter( filter_t *p_filter, picture_t *p_pic )
 244 {
 245     picture_t *p_outpic;
 246
 247     if( !p_pic ) return NULL;
 248
 249     p_outpic = filter_NewPicture( p_filter );
 250     if( !p_outpic )
 251     {
 252         picture_Release( p_pic );
 253         return NULL;
 254     }
 255
 256     vlc_mutex_lock( &p_filter->p_sys->lock );
 257     switch( p_filter->p_sys->i_mode )
 258     {
 259         case EDGE:
 260             FilterEdge( p_filter, p_pic, p_outpic );
 261             break;
 262
 263         case GRADIENT:
 264             FilterGradient( p_filter, p_pic, p_outpic );
 265             break;
 266
 267         case HOUGH:
 268             FilterHough( p_filter, p_pic, p_outpic );
 269             break;
 270
 271         default:
 272             break;
 273     }
 274     vlc_mutex_unlock( &p_filter->p_sys->lock );
 275
 276     return CopyInfoAndRelease( p_outpic, p_pic );
 277 }
 278
 279 /*****************************************************************************
 280  * Gaussian Convolution
 281  *****************************************************************************
 282  *    Gaussian convolution ( sigma == 1.4 )
 283  *
 284  *    |  2  4  5  4  2  |   |  2  4  4  4  2 |
 285  *    |  4  9 12  9  4  |   |  4  8 12  8  4 |
 286  *    |  5 12 15 12  5  | ~ |  4 12 16 12  4 |
 287  *    |  4  9 12  9  4  |   |  4  8 12  8  4 |
 288  *    |  2  4  5  4  2  |   |  2  4  4  4  2 |
 289  *****************************************************************************/
 290 static void GaussianConvolution( picture_t *p_inpic, uint32_t *p_smooth )
 291 {
 292     const uint8_t *p_inpix = p_inpic->p[Y_PLANE].p_pixels;
 293     const int i_src_pitch = p_inpic->p[Y_PLANE].i_pitch;
 294     const int i_src_visible = p_inpic->p[Y_PLANE].i_visible_pitch;
 295     const int i_num_lines = p_inpic->p[Y_PLANE].i_visible_lines;
 296
 297     int x,y;
 298     for( y = 2; y < i_num_lines - 2; y++ )
 299     {
 300         for( x = 2; x < i_src_visible - 2; x++ )
 301         {
 302             p_smooth[y*i_src_visible+x] = (uint32_t)(
 303               /* 2 rows up */
 304                 ( p_inpix[(y-2)*i_src_pitch+x-2] )
 305               + ((p_inpix[(y-2)*i_src_pitch+x-1]
 306               +   p_inpix[(y-2)*i_src_pitch+x]
 307               +   p_inpix[(y-2)*i_src_pitch+x+1])<<1 )
 308               + ( p_inpix[(y-2)*i_src_pitch+x+2] )
 309               /* 1 row up */
 310               + ((p_inpix[(y-1)*i_src_pitch+x-2]
 311               + ( p_inpix[(y-1)*i_src_pitch+x-1]<<1 )
 312               + ( p_inpix[(y-1)*i_src_pitch+x]*3 )
 313               + ( p_inpix[(y-1)*i_src_pitch+x+1]<<1 )
 314               +   p_inpix[(y-1)*i_src_pitch+x+2]
 315               /* */
 316               +   p_inpix[y*i_src_pitch+x-2]
 317               + ( p_inpix[y*i_src_pitch+x-1]*3 )
 318               + ( p_inpix[y*i_src_pitch+x]<<2 )
 319               + ( p_inpix[y*i_src_pitch+x+1]*3 )
 320               +   p_inpix[y*i_src_pitch+x+2]
 321               /* 1 row down */
 322               +   p_inpix[(y+1)*i_src_pitch+x-2]
 323               + ( p_inpix[(y+1)*i_src_pitch+x-1]<<1 )
 324               + ( p_inpix[(y+1)*i_src_pitch+x]*3 )
 325               + ( p_inpix[(y+1)*i_src_pitch+x+1]<<1 )
 326               +   p_inpix[(y+1)*i_src_pitch+x+2] )<<1 )
 327               /* 2 rows down */
 328               + ( p_inpix[(y+2)*i_src_pitch+x-2] )
 329               + ((p_inpix[(y+2)*i_src_pitch+x-1]
 330               +   p_inpix[(y+2)*i_src_pitch+x]
 331               +   p_inpix[(y+2)*i_src_pitch+x+1])<<1 )
 332               + ( p_inpix[(y+2)*i_src_pitch+x+2] )
 333               ) >> 6 /* 115 */;
 334         }
 335     }
 336 }
 337
 338 /*****************************************************************************
 339  * FilterGradient: Sobel
 340  *****************************************************************************/
 341 static void FilterGradient( filter_t *p_filter, picture_t *p_inpic,
 342                                                 picture_t *p_outpic )
 343 {
 344     int x, y;
 345     const int i_src_pitch = p_inpic->p[Y_PLANE].i_pitch;
 346     const int i_src_visible = p_inpic->p[Y_PLANE].i_visible_pitch;
 347     const int i_dst_pitch = p_outpic->p[Y_PLANE].i_pitch;
 348     const int i_num_lines = p_inpic->p[Y_PLANE].i_visible_lines;
 349
 350     const uint8_t *p_inpix = p_inpic->p[Y_PLANE].p_pixels;
 351     uint8_t *p_outpix = p_outpic->p[Y_PLANE].p_pixels;
 352
 353     uint32_t *p_smooth;
 354     if( !p_filter->p_sys->p_buf32 )
 355         p_filter->p_sys->p_buf32 =
 356         (uint32_t *)malloc( i_num_lines * i_src_visible * sizeof(uint32_t));
 357     p_smooth = p_filter->p_sys->p_buf32;
 358
 359     if( !p_smooth ) return;
 360
 361     if( p_filter->p_sys->b_cartoon )
 362     {
 363         plane_CopyPixels( &p_outpic->p[U_PLANE], &p_inpic->p[U_PLANE] );
 364         plane_CopyPixels( &p_outpic->p[V_PLANE], &p_inpic->p[V_PLANE] );
 365     }
 366     else
 367     {
 368         vlc_memset( p_outpic->p[U_PLANE].p_pixels, 0x80,
 369             p_outpic->p[U_PLANE].i_lines * p_outpic->p[U_PLANE].i_pitch );
 370         vlc_memset( p_outpic->p[V_PLANE].p_pixels, 0x80,
 371             p_outpic->p[V_PLANE].i_lines * p_outpic->p[V_PLANE].i_pitch );
 372     }
 373
 374     GaussianConvolution( p_inpic, p_smooth );
 375
 376     /* Sobel gradient
 377
 378      | -1 0 1 |     |  1  2  1 |
 379      | -2 0 2 | and |  0  0  0 |
 380      | -1 0 1 |     | -1 -2 -1 | */
 381
 382 #define FOR                                                     \
 383     for( y = 1; y < i_num_lines - 1; y++ )                      \
 384     {                                                           \
 385         for( x = 1; x < i_src_visible - 1; x++ )                \
 386         {                                                       \
 387             const uint32_t a =                                  \
 388             (                                                   \
 389               abs(                                              \
 390                  ( p_smooth[(y-1)*i_src_visible+x-1]            \
 391                    - p_smooth[(y+1)*i_src_visible+x-1] )        \
 392                + ( ( p_smooth[(y-1)*i_src_visible+x]            \
 393                     - p_smooth[(y+1)*i_src_visible+x] ) <<1 )   \
 394                + ( p_smooth[(y-1)*i_src_visible+x+1]            \
 395                    - p_smooth[(y+1)*i_src_visible+x+1] )        \
 396               )                                                 \
 397             +                                                   \
 398               abs(                                              \
 399                  ( p_smooth[(y-1)*i_src_visible+x-1]            \
 400                    - p_smooth[(y-1)*i_src_visible+x+1] )        \
 401                + ( ( p_smooth[y*i_src_visible+x-1]              \
 402                     - p_smooth[y*i_src_visible+x+1] ) <<1 )     \
 403                + ( p_smooth[(y+1)*i_src_visible+x-1]            \
 404                    - p_smooth[(y+1)*i_src_visible+x+1] )        \
 405               )                                                 \
 406             );
 407     if( p_filter->p_sys->i_gradient_type )
 408     {
 409         if( p_filter->p_sys->b_cartoon )
 410         {
 411             FOR
 412             if( a > 60 )
 413             {
 414                 p_outpix[y*i_dst_pitch+x] = 0x00;
 415             }
 416             else
 417             {
 418                 if( p_smooth[y*i_src_visible+x] > 0xa0 )
 419                     p_outpix[y*i_dst_pitch+x] =
 420                         0xff - ((0xff - p_inpix[y*i_src_pitch+x] )>>2);
 421                 else if( p_smooth[y*i_src_visible+x] > 0x70 )
 422                     p_outpix[y*i_dst_pitch+x] =
 423                         0xa0 - ((0xa0 - p_inpix[y*i_src_pitch+x] )>>2);
 424                 else if( p_smooth[y*i_src_visible+x] > 0x28 )
 425                     p_outpix[y*i_dst_pitch+x] =
 426                         0x70 - ((0x70 - p_inpix[y*i_src_pitch+x] )>>2);
 427                 else
 428                     p_outpix[y*i_dst_pitch+x] =
 429                         0x28 - ((0x28 - p_inpix[y*i_src_pitch+x] )>>2);
 430             }
 431             }}
 432         }
 433         else
 434         {
 435             FOR
 436             p_outpix[y*i_dst_pitch+x] = clip_uint8_vlc( a );
 437             }}
 438         }
 439     }
 440     else
 441     {
 442         FOR
 443         if( a>>8 )
 444             p_outpix[y*i_dst_pitch+x] = 0;
 445         else
 446             p_outpix[y*i_dst_pitch+x] = 0xff-(uint8_t)a;
 447         }}
 448     }
 449 #undef FOR
 450 }
 451
 452 /*****************************************************************************
 453  * FilterEdge: Canny edge detection algorithm
 454  *****************************************************************************
 455  * http://fourier.eng.hmc.edu/e161/lectures/canny/node1.html
 456  * (well ... my implementation isn't really the canny algorithm ... but some
 457  * ideas are the same)
 458  *****************************************************************************/
 459 /* angle : | */
 460 #define THETA_Y 0
 461 /* angle : - */
 462 #define THETA_X 1
 463 /* angle : / */
 464 #define THETA_P 2
 465 /* angle : \ */
 466 #define THETA_M 3
 467 static void FilterEdge( filter_t *p_filter, picture_t *p_inpic,
 468                                             picture_t *p_outpic )
 469 {
 470     int x, y;
 471
 472     const int i_src_pitch = p_inpic->p[Y_PLANE].i_pitch;
 473     const int i_src_visible = p_inpic->p[Y_PLANE].i_visible_pitch;
 474     const int i_dst_pitch = p_outpic->p[Y_PLANE].i_pitch;
 475     const int i_num_lines = p_inpic->p[Y_PLANE].i_visible_lines;
 476
 477     const uint8_t *p_inpix = p_inpic->p[Y_PLANE].p_pixels;
 478     uint8_t *p_outpix = p_outpic->p[Y_PLANE].p_pixels;
 479
 480     uint32_t *p_smooth;
 481     uint32_t *p_grad;
 482     uint8_t *p_theta;
 483
 484     if( !p_filter->p_sys->p_buf32 )
 485         p_filter->p_sys->p_buf32 =
 486         (uint32_t *)malloc( i_num_lines * i_src_visible * sizeof(uint32_t));
 487     p_smooth = p_filter->p_sys->p_buf32;
 488
 489     if( !p_filter->p_sys->p_buf32_bis )
 490         p_filter->p_sys->p_buf32_bis =
 491         (uint32_t *)malloc( i_num_lines * i_src_visible * sizeof(uint32_t));
 492     p_grad = p_filter->p_sys->p_buf32_bis;
 493
 494     if( !p_filter->p_sys->p_buf8 )
 495         p_filter->p_sys->p_buf8 =
 496         (uint8_t *)malloc( i_num_lines * i_src_visible * sizeof(uint8_t));
 497     p_theta = p_filter->p_sys->p_buf8;
 498
 499     if( !p_smooth || !p_grad || !p_theta ) return;
 500
 501     if( p_filter->p_sys->b_cartoon )
 502     {
 503         plane_CopyPixels( &p_outpic->p[U_PLANE], &p_inpic->p[U_PLANE] );
 504         plane_CopyPixels( &p_outpic->p[V_PLANE], &p_inpic->p[V_PLANE] );
 505     }
 506     else
 507     {
 508         vlc_memset( p_outpic->p[Y_PLANE].p_pixels, 0xff,
 509               p_outpic->p[Y_PLANE].i_lines * p_outpic->p[Y_PLANE].i_pitch );
 510         vlc_memset( p_outpic->p[U_PLANE].p_pixels, 0x80,
 511             p_outpic->p[U_PLANE].i_lines * p_outpic->p[U_PLANE].i_pitch );
 512         vlc_memset( p_outpic->p[V_PLANE].p_pixels, 0x80,
 513             p_outpic->p[V_PLANE].i_lines * p_outpic->p[V_PLANE].i_pitch );
 514     }
 515
 516     GaussianConvolution( p_inpic, p_smooth );
 517
 518     /* Sobel gradient
 519
 520      | -1 0 1 |     |  1  2  1 |
 521      | -2 0 2 | and |  0  0  0 |
 522      | -1 0 1 |     | -1 -2 -1 | */
 523
 524     for( y = 1; y < i_num_lines - 1; y++ )
 525     {
 526         for( x = 1; x < i_src_visible - 1; x++ )
 527         {
 528
 529             const int gradx =
 530                  ( p_smooth[(y-1)*i_src_visible+x-1]
 531                    - p_smooth[(y+1)*i_src_visible+x-1] )
 532                + ( ( p_smooth[(y-1)*i_src_visible+x]
 533                     - p_smooth[(y+1)*i_src_visible+x] ) <<1 )
 534                + ( p_smooth[(y-1)*i_src_visible+x+1]
 535                    - p_smooth[(y+1)*i_src_visible+x+1] );
 536             const int grady =
 537                  ( p_smooth[(y-1)*i_src_visible+x-1]
 538                    - p_smooth[(y-1)*i_src_visible+x+1] )
 539                + ( ( p_smooth[y*i_src_visible+x-1]
 540                     - p_smooth[y*i_src_visible+x+1] ) <<1 )
 541                + ( p_smooth[(y+1)*i_src_visible+x-1]
 542                    - p_smooth[(y+1)*i_src_visible+x+1] );
 543
 544             p_grad[y*i_src_visible+x] = (uint32_t)(abs( gradx ) + abs( grady ));
 545
 546             /* tan( 22.5 ) = 0,414213562 .. * 128 = 53
 547              * tan( 26,565051177 ) = 0.5
 548              * tan( 45 + 22.5 ) = 2,414213562 .. * 128 = 309
 549              * tan( 63,434948823 ) 2 */
 550             if( (grady<<1) > gradx )
 551                 p_theta[y*i_src_visible+x] = THETA_P;
 552             else if( (grady<<1) < -gradx )
 553                 p_theta[y*i_src_visible+x] = THETA_M;
 554             else if( !gradx || abs(grady) > abs(gradx)<<1 )
 555                 p_theta[y*i_src_visible+x] = THETA_Y;
 556             else
 557                 p_theta[y*i_src_visible+x] = THETA_X;
 558         }
 559     }
 560
 561     /* edge computing */
 562     for( y = 1; y < i_num_lines - 1; y++ )
 563     {
 564         for( x = 1; x < i_src_visible - 1; x++ )
 565         {
 566             if( p_grad[y*i_src_visible+x] > 40 )
 567             {
 568                 switch( p_theta[y*i_src_visible+x] )
 569                 {
 570                     case THETA_Y:
 571                         if(    p_grad[y*i_src_visible+x] > p_grad[(y-1)*i_src_visible+x]
 572                             && p_grad[y*i_src_visible+x] > p_grad[(y+1)*i_src_visible+x] )
 573                         {
 574                             p_outpix[y*i_dst_pitch+x] = 0;
 575                             break;
 576                         } else goto colorize;
 577                     case THETA_P:
 578                         if(    p_grad[y*i_src_visible+x] > p_grad[(y-1)*i_src_visible+x-1]
 579                             && p_grad[y*i_src_visible+x] > p_grad[(y+1)*i_src_visible+x+1] )
 580                         {
 581                             p_outpix[y*i_dst_pitch+x] = 0;
 582                             break;
 583                         } else goto colorize;
 584                     case THETA_M:
 585                         if(    p_grad[y*i_src_visible+x] > p_grad[(y-1)*i_src_visible+x+1]
 586                             && p_grad[y*i_src_visible+x] > p_grad[(y+1)*i_src_visible+x-1] )
 587                         {
 588                             p_outpix[y*i_dst_pitch+x] = 0;
 589                             break;
 590                         } else goto colorize;
 591                     case THETA_X:
 592                         if(    p_grad[y*i_src_visible+x] > p_grad[y*i_src_visible+x-1]
 593                             && p_grad[y*i_src_visible+x] > p_grad[y*i_src_visible+x+1] )
 594                         {
 595                             p_outpix[y*i_dst_pitch+x] = 0;
 596                             break;
 597                         } else goto colorize;
 598                 }
 599             }
 600             else
 601             {
 602                 colorize:
 603                 if( p_filter->p_sys->b_cartoon )
 604                 {
 605                     if( p_smooth[y*i_src_visible+x] > 0xa0 )
 606                         p_outpix[y*i_dst_pitch+x] = (uint8_t)
 607                             0xff - ((0xff - p_inpix[y*i_src_pitch+x] )>>2);
 608                     else if( p_smooth[y*i_src_visible+x] > 0x70 )
 609                         p_outpix[y*i_dst_pitch+x] =(uint8_t)
 610                             0xa0 - ((0xa0 - p_inpix[y*i_src_pitch+x] )>>2);
 611                     else if( p_smooth[y*i_src_visible+x] > 0x28 )
 612                         p_outpix[y*i_dst_pitch+x] =(uint8_t)
 613                             0x70 - ((0x70 - p_inpix[y*i_src_pitch+x] )>>2);
 614                     else
 615                         p_outpix[y*i_dst_pitch+x] =(uint8_t)
 616                             0x28 - ((0x28 - p_inpix[y*i_src_pitch+x] )>>2);
 617                 }
 618             }
 619         }
 620     }
 621 }
 622
 623 /*****************************************************************************
 624  * FilterHough
 625  *****************************************************************************/
 626 #define p_pre_hough p_filter->p_sys->p_pre_hough
 627 static void FilterHough( filter_t *p_filter, picture_t *p_inpic,
 628                                              picture_t *p_outpic )
 629 {
 630     int x, y, i;
 631     int i_src_visible = p_inpic->p[Y_PLANE].i_visible_pitch;
 632     int i_dst_pitch = p_outpic->p[Y_PLANE].i_pitch;
 633     int i_num_lines = p_inpic->p[Y_PLANE].i_visible_lines;
 634
 635     uint8_t *p_outpix = p_outpic->p[Y_PLANE].p_pixels;
 636
 637     int i_diag = sqrt( i_num_lines * i_num_lines +
 638                         i_src_visible * i_src_visible);
 639     int i_max, i_phi_max, i_rho, i_rho_max;
 640     int i_nb_steps = 90;
 641     double d_step = M_PI / i_nb_steps;
 642     double d_sin;
 643     double d_cos;
 644     uint32_t *p_smooth;
 645
 646     int *p_hough = malloc( i_diag * i_nb_steps * sizeof(int) );
 647     if( ! p_hough ) return;
 648
 649     p_smooth = (uint32_t *)malloc( i_num_lines*i_src_visible*sizeof(uint32_t));
 650     if( !p_smooth )
 651     {
 652         free( p_hough );
 653         return;
 654     }
 655
 656     if( ! p_pre_hough )
 657     {
 658         msg_Dbg(p_filter, "Starting precalculation");
 659         p_pre_hough = malloc( i_num_lines*i_src_visible*i_nb_steps*sizeof(int));
 660         if( ! p_pre_hough )
 661         {
 662             free( p_smooth );
 663             free( p_hough );
 664             return;
 665         }
 666         for( i = 0 ; i < i_nb_steps ; i++)
 667         {
 668             d_sin = sin(d_step * i);
 669             d_cos = cos(d_step * i);
 670             for( y = 0 ; y < i_num_lines ; y++ )
 671                 for( x = 0 ; x < i_src_visible ; x++ )
 672                 {
 673                     p_pre_hough[(i*i_num_lines+y)*i_src_visible + x] =
 674                         ceil(x*d_sin + y*d_cos);
 675                 }
 676         }
 677         msg_Dbg(p_filter, "Precalculation done");
 678     }
 679
 680     vlc_memset( p_hough, 0, i_diag * i_nb_steps * sizeof(int) );
 681
 682     plane_CopyPixels( &p_outpic->p[Y_PLANE], &p_inpic->p[Y_PLANE] );
 683     plane_CopyPixels( &p_outpic->p[U_PLANE], &p_inpic->p[U_PLANE] );
 684     plane_CopyPixels( &p_outpic->p[V_PLANE], &p_inpic->p[V_PLANE] );
 685
 686     GaussianConvolution( p_inpic, p_smooth );
 687
 688     /* Sobel gradient
 689
 690      | -1 0 1 |     |  1  2  1 |
 691      | -2 0 2 | and |  0  0  0 |
 692      | -1 0 1 |     | -1 -2 -1 | */
 693
 694     i_max = 0;
 695     i_rho_max = 0;
 696     i_phi_max = 0;
 697     for( y = 4; y < i_num_lines - 4; y++ )
 698     {
 699         for( x = 4; x < i_src_visible - 4; x++ )
 700         {
 701             uint32_t a =
 702             (
 703               abs(
 704                 ( ( p_smooth[(y-1)*i_src_visible+x]
 705                     - p_smooth[(y+1)*i_src_visible+x] ) <<1 )
 706                + ( p_smooth[(y-1)*i_src_visible+x-1]
 707                    - p_smooth[(y+1)*i_src_visible+x-1] )
 708                + ( p_smooth[(y-1)*i_src_visible+x+1]
 709                    - p_smooth[(y+1)*i_src_visible+x+1] )
 710               )
 711             +
 712               abs(
 713                 ( ( p_smooth[y*i_src_visible+x-1]
 714                     - p_smooth[y*i_src_visible+x+1] ) <<1 )
 715                + ( p_smooth[(y-1)*i_src_visible+x-1]
 716                    - p_smooth[(y-1)*i_src_visible+x+1] )
 717                + ( p_smooth[(y+1)*i_src_visible+x-1]
 718                    - p_smooth[(y+1)*i_src_visible+x+1] )
 719               )
 720             );
 721             if( a>>8 )
 722             {
 723                 for( i = 0 ; i < i_nb_steps ; i ++ )
 724                 {
 725                     i_rho = p_pre_hough[(i*i_num_lines+y)*i_src_visible + x];
 726                     if( p_hough[i_rho + i_diag/2 + i * i_diag]++ > i_max )
 727                     {
 728                         i_max = p_hough[i_rho + i_diag/2 + i * i_diag];
 729                         i_rho_max = i_rho;
 730                         i_phi_max = i;
 731                     }
 732                 }
 733             }
 734         }
 735     }
 736
 737     d_sin = sin(i_phi_max*d_step);
 738     d_cos = cos(i_phi_max*d_step);
 739     if( d_cos != 0 )
 740     {
 741         for( x = 0 ; x < i_src_visible ; x++ )
 742         {
 743             y = (i_rho_max - x * d_sin) / d_cos;
 744             if( y >= 0 && y < i_num_lines )
 745                 p_outpix[y*i_dst_pitch+x] = 255;
 746         }
 747     }
 748
 749     free( p_hough );
 750     free( p_smooth );
 751 }
 752 #undef p_pre_hough
 753
 754
 755 static int GradientCallback( vlc_object_t *p_this, char const *psz_var,
 756                              vlc_value_t oldval, vlc_value_t newval,
 757                              void *p_data )
 758 {
 759     VLC_UNUSED(oldval);
 760     filter_sys_t *p_sys = (filter_sys_t *)p_data;
 761
 762     vlc_mutex_lock( &p_sys->lock );
 763     if( !strcmp( psz_var, FILTER_PREFIX "mode" ) )
 764     {
 765         if( !strcmp( newval.psz_string, "gradient" ) )
 766         {
 767             p_sys->i_mode = GRADIENT;
 768         }
 769         else if( !strcmp( newval.psz_string, "edge" ) )
 770         {
 771             p_sys->i_mode = EDGE;
 772         }
 773         else if( !strcmp( newval.psz_string, "hough" ) )
 774         {
 775             p_sys->i_mode = HOUGH;
 776         }
 777         else
 778         {
 779             msg_Err( p_this, "no valid gradient mode provided (%s)", newval.psz_string );
 780             p_sys->i_mode = GRADIENT;
 781         }
 782     }
 783     else if( !strcmp( psz_var, FILTER_PREFIX "type" ) )
 784     {
 785         p_sys->i_gradient_type = newval.i_int;
 786     }
 787     else if( !strcmp( psz_var, FILTER_PREFIX "cartoon" ) )
 788     {
 789         p_sys->b_cartoon = newval.b_bool;
 790     }
 791     vlc_mutex_unlock( &p_sys->lock );
 792
 793     return VLC_SUCCESS;
 794 }