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) 2000-2006 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/vlc.h>
  36 #include <vlc_plugin.h>
  37 #include <vlc_sout.h>
  38 #include <vlc_vout.h>
  39
  40 #include "vlc_filter.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 static const char *mode_list[] = { "gradient", "edge", "hough" };
  74 static const char *mode_list_text[] = { N_("Gradient"), N_("Edge"), N_("Hough") };
  75
  76 #define FILTER_PREFIX "gradient-"
  77
  78 vlc_module_begin();
  79     set_description( _("Gradient video filter") );
  80     set_shortname( _( "Gradient" ));
  81     set_capability( "video filter2", 0 );
  82     set_category( CAT_VIDEO );
  83     set_subcategory( SUBCAT_VIDEO_VFILTER );
  84
  85     add_string( FILTER_PREFIX "mode", "gradient", NULL,
  86                 MODE_TEXT, MODE_LONGTEXT, false );
  87         change_string_list( mode_list, mode_list_text, 0 );
  88
  89     add_integer_with_range( FILTER_PREFIX "type", 0, 0, 1, NULL,
  90                 GRADIENT_TEXT, GRADIENT_LONGTEXT, false );
  91     add_bool( FILTER_PREFIX "cartoon", 1, NULL,
  92                 CARTOON_TEXT, CARTOON_LONGTEXT, false );
  93
  94     add_shortcut( "gradient" );
  95     set_callbacks( Create, Destroy );
  96 vlc_module_end();
  97
  98 static const char *ppsz_filter_options[] = {
  99     "mode", "type", "cartoon", NULL
 100 };
 101
 102 /*****************************************************************************
 103  * vout_sys_t: Distort video output method descriptor
 104  *****************************************************************************
 105  * This structure is part of the video output thread descriptor.
 106  * It describes the Distort specific properties of an output thread.
 107  *****************************************************************************/
 108 struct filter_sys_t
 109 {
 110     int i_mode;
 111
 112     /* For the gradient mode */
 113     int i_gradient_type;
 114     bool b_cartoon;
 115
 116     uint32_t *p_buf32;
 117     uint32_t *p_buf32_bis;
 118     uint8_t *p_buf8;
 119
 120     /* For hough mode */
 121     int *p_pre_hough;
 122 };
 123
 124 /*****************************************************************************
 125  * Create: allocates Distort video thread output method
 126  *****************************************************************************
 127  * This function allocates and initializes a Distort vout method.
 128  *****************************************************************************/
 129 static int Create( vlc_object_t *p_this )
 130 {
 131     filter_t *p_filter = (filter_t *)p_this;
 132     char *psz_method;
 133
 134     /* Allocate structure */
 135     p_filter->p_sys = malloc( sizeof( filter_sys_t ) );
 136     if( p_filter->p_sys == NULL )
 137     {
 138         msg_Err( p_filter, "out of memory" );
 139         return VLC_ENOMEM;
 140     }
 141
 142     p_filter->pf_video_filter = Filter;
 143
 144     p_filter->p_sys->p_pre_hough = NULL;
 145
 146     config_ChainParse( p_filter, FILTER_PREFIX, ppsz_filter_options,
 147                    p_filter->p_cfg );
 148
 149     if( !(psz_method =
 150         var_CreateGetNonEmptyStringCommand( p_filter, FILTER_PREFIX "mode" )) )
 151     {
 152         msg_Err( p_filter, "configuration variable "
 153                  FILTER_PREFIX "mode empty" );
 154         p_filter->p_sys->i_mode = GRADIENT;
 155     }
 156     else
 157     {
 158         if( !strcmp( psz_method, "gradient" ) )
 159         {
 160             p_filter->p_sys->i_mode = GRADIENT;
 161         }
 162         else if( !strcmp( psz_method, "edge" ) )
 163         {
 164             p_filter->p_sys->i_mode = EDGE;
 165         }
 166         else if( !strcmp( psz_method, "hough" ) )
 167         {
 168             p_filter->p_sys->i_mode = HOUGH;
 169         }
 170         else
 171         {
 172             msg_Err( p_filter, "no valid gradient mode provided (%s)", psz_method );
 173             p_filter->p_sys->i_mode = GRADIENT;
 174         }
 175     }
 176     free( psz_method );
 177
 178     p_filter->p_sys->i_gradient_type =
 179         var_CreateGetIntegerCommand( p_filter, FILTER_PREFIX "type" );
 180     p_filter->p_sys->b_cartoon =
 181         var_CreateGetBoolCommand( p_filter, FILTER_PREFIX "cartoon" );
 182
 183     var_AddCallback( p_filter, FILTER_PREFIX "mode",
 184                      GradientCallback, p_filter->p_sys );
 185     var_AddCallback( p_filter, FILTER_PREFIX "type",
 186                      GradientCallback, p_filter->p_sys );
 187     var_AddCallback( p_filter, FILTER_PREFIX "cartoon",
 188                      GradientCallback, p_filter->p_sys );
 189
 190     p_filter->p_sys->p_buf32 = NULL;
 191     p_filter->p_sys->p_buf32_bis = NULL;
 192     p_filter->p_sys->p_buf8 = NULL;
 193
 194     return VLC_SUCCESS;
 195 }
 196
 197 /*****************************************************************************
 198  * Destroy: destroy Distort video thread output method
 199  *****************************************************************************
 200  * Terminate an output method created by DistortCreateOutputMethod
 201  *****************************************************************************/
 202 static void Destroy( vlc_object_t *p_this )
 203 {
 204     filter_t *p_filter = (filter_t *)p_this;
 205
 206     free( p_filter->p_sys->p_buf32 );
 207     free( p_filter->p_sys->p_buf32_bis );
 208     free( p_filter->p_sys->p_buf8 );
 209     free( p_filter->p_sys->p_pre_hough );
 210
 211     free( p_filter->p_sys );
 212 }
 213
 214 /*****************************************************************************
 215  * Render: displays previously rendered output
 216  *****************************************************************************
 217  * This function send the currently rendered image to Distort image, waits
 218  * until it is displayed and switch the two rendering buffers, preparing next
 219  * frame.
 220  *****************************************************************************/
 221 static picture_t *Filter( filter_t *p_filter, picture_t *p_pic )
 222 {
 223     picture_t *p_outpic;
 224
 225     if( !p_pic ) return NULL;
 226
 227     p_outpic = p_filter->pf_vout_buffer_new( p_filter );
 228     if( !p_outpic )
 229     {
 230         msg_Warn( p_filter, "can't get output picture" );
 231         if( p_pic->pf_release )
 232             p_pic->pf_release( p_pic );
 233         return NULL;
 234     }
 235
 236     switch( p_filter->p_sys->i_mode )
 237     {
 238         case EDGE:
 239             FilterEdge( p_filter, p_pic, p_outpic );
 240             break;
 241
 242         case GRADIENT:
 243             FilterGradient( p_filter, p_pic, p_outpic );
 244             break;
 245
 246         case HOUGH:
 247             FilterHough( p_filter, p_pic, p_outpic );
 248             break;
 249
 250         default:
 251             break;
 252     }
 253
 254     p_outpic->date = p_pic->date;
 255     p_outpic->b_force = p_pic->b_force;
 256     p_outpic->i_nb_fields = p_pic->i_nb_fields;
 257     p_outpic->b_progressive = p_pic->b_progressive;
 258     p_outpic->b_top_field_first = p_pic->b_top_field_first;
 259
 260     if( p_pic->pf_release )
 261         p_pic->pf_release( p_pic );
 262
 263     return p_outpic;
 264 }
 265
 266 /*****************************************************************************
 267  * Gaussian Convolution
 268  *****************************************************************************
 269  *    Gaussian convolution ( sigma == 1.4 )
 270  *
 271  *    |  2  4  5  4  2  |   |  2  4  4  4  2 |
 272  *    |  4  9 12  9  4  |   |  4  8 12  8  4 |
 273  *    |  5 12 15 12  5  | ~ |  4 12 16 12  4 |
 274  *    |  4  9 12  9  4  |   |  4  8 12  8  4 |
 275  *    |  2  4  5  4  2  |   |  2  4  4  4  2 |
 276  *****************************************************************************/
 277 static void GaussianConvolution( picture_t *p_inpic, uint32_t *p_smooth )
 278 {
 279     const uint8_t *p_inpix = p_inpic->p[Y_PLANE].p_pixels;
 280     const int i_src_pitch = p_inpic->p[Y_PLANE].i_pitch;
 281     const int i_src_visible = p_inpic->p[Y_PLANE].i_visible_pitch;
 282     const int i_num_lines = p_inpic->p[Y_PLANE].i_visible_lines;
 283
 284     int x,y;
 285     for( y = 2; y < i_num_lines - 2; y++ )
 286     {
 287         for( x = 2; x < i_src_visible - 2; x++ )
 288         {
 289             p_smooth[y*i_src_visible+x] = (uint32_t)(
 290               /* 2 rows up */
 291                 ( p_inpix[(y-2)*i_src_pitch+x-2] )
 292               + ((p_inpix[(y-2)*i_src_pitch+x-1]
 293               +   p_inpix[(y-2)*i_src_pitch+x]
 294               +   p_inpix[(y-2)*i_src_pitch+x+1])<<1 )
 295               + ( p_inpix[(y-2)*i_src_pitch+x+2] )
 296               /* 1 row up */
 297               + ((p_inpix[(y-1)*i_src_pitch+x-2]
 298               + ( p_inpix[(y-1)*i_src_pitch+x-1]<<1 )
 299               + ( p_inpix[(y-1)*i_src_pitch+x]*3 )
 300               + ( p_inpix[(y-1)*i_src_pitch+x+1]<<1 )
 301               +   p_inpix[(y-1)*i_src_pitch+x+2]
 302               /* */
 303               +   p_inpix[y*i_src_pitch+x-2]
 304               + ( p_inpix[y*i_src_pitch+x-1]*3 )
 305               + ( p_inpix[y*i_src_pitch+x]<<2 )
 306               + ( p_inpix[y*i_src_pitch+x+1]*3 )
 307               +   p_inpix[y*i_src_pitch+x+2]
 308               /* 1 row down */
 309               +   p_inpix[(y+1)*i_src_pitch+x-2]
 310               + ( p_inpix[(y+1)*i_src_pitch+x-1]<<1 )
 311               + ( p_inpix[(y+1)*i_src_pitch+x]*3 )
 312               + ( p_inpix[(y+1)*i_src_pitch+x+1]<<1 )
 313               +   p_inpix[(y+1)*i_src_pitch+x+2] )<<1 )
 314               /* 2 rows down */
 315               + ( p_inpix[(y+2)*i_src_pitch+x-2] )
 316               + ((p_inpix[(y+2)*i_src_pitch+x-1]
 317               +   p_inpix[(y+2)*i_src_pitch+x]
 318               +   p_inpix[(y+2)*i_src_pitch+x+1])<<1 )
 319               + ( p_inpix[(y+2)*i_src_pitch+x+2] )
 320               ) >> 6 /* 115 */;
 321         }
 322     }
 323 }
 324
 325 /*****************************************************************************
 326  * FilterGradient: Sobel
 327  *****************************************************************************/
 328 static void FilterGradient( filter_t *p_filter, picture_t *p_inpic,
 329                                                 picture_t *p_outpic )
 330 {
 331     int x, y;
 332     const int i_src_pitch = p_inpic->p[Y_PLANE].i_pitch;
 333     const int i_src_visible = p_inpic->p[Y_PLANE].i_visible_pitch;
 334     const int i_dst_pitch = p_outpic->p[Y_PLANE].i_pitch;
 335     const int i_num_lines = p_inpic->p[Y_PLANE].i_visible_lines;
 336
 337     const uint8_t *p_inpix = p_inpic->p[Y_PLANE].p_pixels;
 338     uint8_t *p_outpix = p_outpic->p[Y_PLANE].p_pixels;
 339
 340     uint32_t *p_smooth;
 341     if( !p_filter->p_sys->p_buf32 )
 342         p_filter->p_sys->p_buf32 =
 343         (uint32_t *)malloc( i_num_lines * i_src_visible * sizeof(uint32_t));
 344     p_smooth = p_filter->p_sys->p_buf32;
 345
 346     if( !p_smooth ) return;
 347
 348     if( p_filter->p_sys->b_cartoon )
 349     {
 350         vlc_memcpy( p_outpic->p[U_PLANE].p_pixels,
 351             p_inpic->p[U_PLANE].p_pixels,
 352             p_outpic->p[U_PLANE].i_lines * p_outpic->p[U_PLANE].i_pitch );
 353         vlc_memcpy( p_outpic->p[V_PLANE].p_pixels,
 354             p_inpic->p[V_PLANE].p_pixels,
 355             p_outpic->p[V_PLANE].i_lines * p_outpic->p[V_PLANE].i_pitch );
 356     }
 357     else
 358     {
 359         vlc_memset( p_outpic->p[U_PLANE].p_pixels, 0x80,
 360             p_outpic->p[U_PLANE].i_lines * p_outpic->p[U_PLANE].i_pitch );
 361         vlc_memset( p_outpic->p[V_PLANE].p_pixels, 0x80,
 362             p_outpic->p[V_PLANE].i_lines * p_outpic->p[V_PLANE].i_pitch );
 363     }
 364
 365     GaussianConvolution( p_inpic, p_smooth );
 366
 367     /* Sobel gradient
 368
 369      | -1 0 1 |     |  1  2  1 |
 370      | -2 0 2 | and |  0  0  0 |
 371      | -1 0 1 |     | -1 -2 -1 | */
 372
 373 #define FOR                                                     \
 374     for( y = 1; y < i_num_lines - 1; y++ )                      \
 375     {                                                           \
 376         for( x = 1; x < i_src_visible - 1; x++ )                \
 377         {                                                       \
 378             const uint32_t a =                                  \
 379             (                                                   \
 380               abs(                                              \
 381                  ( p_smooth[(y-1)*i_src_visible+x-1]            \
 382                    - p_smooth[(y+1)*i_src_visible+x-1] )        \
 383                + ( ( p_smooth[(y-1)*i_src_visible+x]            \
 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+1] )        \
 387               )                                                 \
 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*i_src_visible+x-1]              \
 393                     - p_smooth[y*i_src_visible+x+1] ) <<1 )     \
 394                + ( p_smooth[(y+1)*i_src_visible+x-1]            \
 395                    - p_smooth[(y+1)*i_src_visible+x+1] )        \
 396               )                                                 \
 397             );
 398     if( p_filter->p_sys->i_gradient_type )
 399     {
 400         if( p_filter->p_sys->b_cartoon )
 401         {
 402             FOR
 403             if( a > 60 )
 404             {
 405                 p_outpix[y*i_dst_pitch+x] = 0x00;
 406             }
 407             else
 408             {
 409                 if( p_smooth[y*i_src_visible+x] > 0xa0 )
 410                     p_outpix[y*i_dst_pitch+x] =
 411                         0xff - ((0xff - p_inpix[y*i_src_pitch+x] )>>2);
 412                 else if( p_smooth[y*i_src_visible+x] > 0x70 )
 413                     p_outpix[y*i_dst_pitch+x] =
 414                         0xa0 - ((0xa0 - p_inpix[y*i_src_pitch+x] )>>2);
 415                 else if( p_smooth[y*i_src_visible+x] > 0x28 )
 416                     p_outpix[y*i_dst_pitch+x] =
 417                         0x70 - ((0x70 - p_inpix[y*i_src_pitch+x] )>>2);
 418                 else
 419                     p_outpix[y*i_dst_pitch+x] =
 420                         0x28 - ((0x28 - p_inpix[y*i_src_pitch+x] )>>2);
 421             }
 422             }}
 423         }
 424         else
 425         {
 426             FOR
 427             p_outpix[y*i_dst_pitch+x] = clip_uint8_vlc( a );
 428             }}
 429         }
 430     }
 431     else
 432     {
 433         FOR
 434         if( a>>8 )
 435             p_outpix[y*i_dst_pitch+x] = 0;
 436         else
 437             p_outpix[y*i_dst_pitch+x] = 0xff-(uint8_t)a;
 438         }}
 439     }
 440 #undef FOR
 441 }
 442
 443 /*****************************************************************************
 444  * FilterEdge: Canny edge detection algorithm
 445  *****************************************************************************
 446  * http://fourier.eng.hmc.edu/e161/lectures/canny/node1.html
 447  * (well ... my implementation isn't really the canny algorithm ... but some
 448  * ideas are the same)
 449  *****************************************************************************/
 450 /* angle : | */
 451 #define THETA_Y 0
 452 /* angle : - */
 453 #define THETA_X 1
 454 /* angle : / */
 455 #define THETA_P 2
 456 /* angle : \ */
 457 #define THETA_M 3
 458 static void FilterEdge( filter_t *p_filter, picture_t *p_inpic,
 459                                             picture_t *p_outpic )
 460 {
 461     int x, y;
 462
 463     const int i_src_pitch = p_inpic->p[Y_PLANE].i_pitch;
 464     const int i_src_visible = p_inpic->p[Y_PLANE].i_visible_pitch;
 465     const int i_dst_pitch = p_outpic->p[Y_PLANE].i_pitch;
 466     const int i_num_lines = p_inpic->p[Y_PLANE].i_visible_lines;
 467
 468     const uint8_t *p_inpix = p_inpic->p[Y_PLANE].p_pixels;
 469     uint8_t *p_outpix = p_outpic->p[Y_PLANE].p_pixels;
 470
 471     uint32_t *p_smooth;
 472     uint32_t *p_grad;
 473     uint8_t *p_theta;
 474
 475     if( !p_filter->p_sys->p_buf32 )
 476         p_filter->p_sys->p_buf32 =
 477         (uint32_t *)malloc( i_num_lines * i_src_visible * sizeof(uint32_t));
 478     p_smooth = p_filter->p_sys->p_buf32;
 479
 480     if( !p_filter->p_sys->p_buf32_bis )
 481         p_filter->p_sys->p_buf32_bis =
 482         (uint32_t *)malloc( i_num_lines * i_src_visible * sizeof(uint32_t));
 483     p_grad = p_filter->p_sys->p_buf32_bis;
 484
 485     if( !p_filter->p_sys->p_buf8 )
 486         p_filter->p_sys->p_buf8 =
 487         (uint8_t *)malloc( i_num_lines * i_src_visible * sizeof(uint8_t));
 488     p_theta = p_filter->p_sys->p_buf8;
 489
 490     if( !p_smooth || !p_grad || !p_theta ) return;
 491
 492     if( p_filter->p_sys->b_cartoon )
 493     {
 494         vlc_memcpy( p_outpic->p[U_PLANE].p_pixels,
 495             p_inpic->p[U_PLANE].p_pixels,
 496             p_outpic->p[U_PLANE].i_lines * p_outpic->p[U_PLANE].i_pitch );
 497         vlc_memcpy( p_outpic->p[V_PLANE].p_pixels,
 498             p_inpic->p[V_PLANE].p_pixels,
 499             p_outpic->p[V_PLANE].i_lines * p_outpic->p[V_PLANE].i_pitch );
 500     }
 501     else
 502     {
 503         vlc_memset( p_outpic->p[Y_PLANE].p_pixels, 0xff,
 504               p_outpic->p[Y_PLANE].i_lines * p_outpic->p[Y_PLANE].i_pitch );
 505         vlc_memset( p_outpic->p[U_PLANE].p_pixels, 0x80,
 506             p_outpic->p[U_PLANE].i_lines * p_outpic->p[U_PLANE].i_pitch );
 507         vlc_memset( p_outpic->p[V_PLANE].p_pixels, 0x80,
 508             p_outpic->p[V_PLANE].i_lines * p_outpic->p[V_PLANE].i_pitch );
 509     }
 510
 511     GaussianConvolution( p_inpic, p_smooth );
 512
 513     /* Sobel gradient
 514
 515      | -1 0 1 |     |  1  2  1 |
 516      | -2 0 2 | and |  0  0  0 |
 517      | -1 0 1 |     | -1 -2 -1 | */
 518
 519     for( y = 1; y < i_num_lines - 1; y++ )
 520     {
 521         for( x = 1; x < i_src_visible - 1; x++ )
 522         {
 523
 524             const int gradx =
 525                  ( p_smooth[(y-1)*i_src_visible+x-1]
 526                    - p_smooth[(y+1)*i_src_visible+x-1] )
 527                + ( ( p_smooth[(y-1)*i_src_visible+x]
 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+1] );
 531             const int grady =
 532                  ( p_smooth[(y-1)*i_src_visible+x-1]
 533                    - p_smooth[(y-1)*i_src_visible+x+1] )
 534                + ( ( p_smooth[y*i_src_visible+x-1]
 535                     - p_smooth[y*i_src_visible+x+1] ) <<1 )
 536                + ( p_smooth[(y+1)*i_src_visible+x-1]
 537                    - p_smooth[(y+1)*i_src_visible+x+1] );
 538
 539             p_grad[y*i_src_visible+x] = (uint32_t)(abs( gradx ) + abs( grady ));
 540
 541             /* tan( 22.5 ) = 0,414213562 .. * 128 = 53
 542              * tan( 26,565051177 ) = 0.5
 543              * tan( 45 + 22.5 ) = 2,414213562 .. * 128 = 309
 544              * tan( 63,434948823 ) 2 */
 545             if( (grady<<1) > gradx )
 546                 p_theta[y*i_src_visible+x] = THETA_P;
 547             else if( (grady<<1) < -gradx )
 548                 p_theta[y*i_src_visible+x] = THETA_M;
 549             else if( !gradx || abs(grady) > abs(gradx)<<1 )
 550                 p_theta[y*i_src_visible+x] = THETA_Y;
 551             else
 552                 p_theta[y*i_src_visible+x] = THETA_X;
 553         }
 554     }
 555
 556     /* edge computing */
 557     for( y = 1; y < i_num_lines - 1; y++ )
 558     {
 559         for( x = 1; x < i_src_visible - 1; x++ )
 560         {
 561             if( p_grad[y*i_src_visible+x] > 40 )
 562             {
 563                 switch( p_theta[y*i_src_visible+x] )
 564                 {
 565                     case THETA_Y:
 566                         if(    p_grad[y*i_src_visible+x] > p_grad[(y-1)*i_src_visible+x]
 567                             && p_grad[y*i_src_visible+x] > p_grad[(y+1)*i_src_visible+x] )
 568                         {
 569                             p_outpix[y*i_dst_pitch+x] = 0;
 570                             break;
 571                         } else goto colorize;
 572                     case THETA_P:
 573                         if(    p_grad[y*i_src_visible+x] > p_grad[(y-1)*i_src_visible+x-1]
 574                             && p_grad[y*i_src_visible+x] > p_grad[(y+1)*i_src_visible+x+1] )
 575                         {
 576                             p_outpix[y*i_dst_pitch+x] = 0;
 577                             break;
 578                         } else goto colorize;
 579                     case THETA_M:
 580                         if(    p_grad[y*i_src_visible+x] > p_grad[(y-1)*i_src_visible+x+1]
 581                             && p_grad[y*i_src_visible+x] > p_grad[(y+1)*i_src_visible+x-1] )
 582                         {
 583                             p_outpix[y*i_dst_pitch+x] = 0;
 584                             break;
 585                         } else goto colorize;
 586                     case THETA_X:
 587                         if(    p_grad[y*i_src_visible+x] > p_grad[y*i_src_visible+x-1]
 588                             && p_grad[y*i_src_visible+x] > p_grad[y*i_src_visible+x+1] )
 589                         {
 590                             p_outpix[y*i_dst_pitch+x] = 0;
 591                             break;
 592                         } else goto colorize;
 593                 }
 594             }
 595             else
 596             {
 597                 colorize:
 598                 if( p_filter->p_sys->b_cartoon )
 599                 {
 600                     if( p_smooth[y*i_src_visible+x] > 0xa0 )
 601                         p_outpix[y*i_dst_pitch+x] = (uint8_t)
 602                             0xff - ((0xff - p_inpix[y*i_src_pitch+x] )>>2);
 603                     else if( p_smooth[y*i_src_visible+x] > 0x70 )
 604                         p_outpix[y*i_dst_pitch+x] =(uint8_t)
 605                             0xa0 - ((0xa0 - p_inpix[y*i_src_pitch+x] )>>2);
 606                     else if( p_smooth[y*i_src_visible+x] > 0x28 )
 607                         p_outpix[y*i_dst_pitch+x] =(uint8_t)
 608                             0x70 - ((0x70 - p_inpix[y*i_src_pitch+x] )>>2);
 609                     else
 610                         p_outpix[y*i_dst_pitch+x] =(uint8_t)
 611                             0x28 - ((0x28 - p_inpix[y*i_src_pitch+x] )>>2);
 612                 }
 613             }
 614         }
 615     }
 616 }
 617
 618 /*****************************************************************************
 619  * FilterHough
 620  *****************************************************************************/
 621 #define p_pre_hough p_filter->p_sys->p_pre_hough
 622 static void FilterHough( filter_t *p_filter, picture_t *p_inpic,
 623                                              picture_t *p_outpic )
 624 {
 625     int x, y, i;
 626     int i_src_visible = p_inpic->p[Y_PLANE].i_visible_pitch;
 627     int i_dst_pitch = p_outpic->p[Y_PLANE].i_pitch;
 628     int i_num_lines = p_inpic->p[Y_PLANE].i_visible_lines;
 629
 630     uint8_t *p_outpix = p_outpic->p[Y_PLANE].p_pixels;
 631
 632     int i_diag = sqrt( i_num_lines * i_num_lines +
 633                         i_src_visible * i_src_visible);
 634     int i_max, i_phi_max, i_rho, i_rho_max;
 635     int i_nb_steps = 90;
 636     double d_step = M_PI / i_nb_steps;
 637     double d_sin;
 638     double d_cos;
 639     uint32_t *p_smooth;
 640     int *p_hough = malloc( i_diag * i_nb_steps * sizeof(int) );
 641     if( ! p_hough ) return;
 642     p_smooth = (uint32_t *)malloc( i_num_lines*i_src_visible*sizeof(uint32_t));
 643     if( !p_smooth ) return;
 644
 645     if( ! p_pre_hough )
 646     {
 647         msg_Dbg(p_filter, "Starting precalculation");
 648         p_pre_hough = malloc( i_num_lines*i_src_visible*i_nb_steps*sizeof(int));
 649         if( ! p_pre_hough ) return;
 650         for( i = 0 ; i < i_nb_steps ; i++)
 651         {
 652             d_sin = sin(d_step * i);
 653             d_cos = cos(d_step * i);
 654             for( y = 0 ; y < i_num_lines ; y++ )
 655                 for( x = 0 ; x < i_src_visible ; x++ )
 656                 {
 657                     p_pre_hough[(i*i_num_lines+y)*i_src_visible + x] =
 658                         ceil(x*d_sin + y*d_cos);
 659                 }
 660         }
 661         msg_Dbg(p_filter, "Precalculation done");
 662     }
 663
 664     vlc_memset( p_hough, 0, i_diag * i_nb_steps * sizeof(int) );
 665
 666     vlc_memcpy(
 667         p_outpic->p[Y_PLANE].p_pixels, p_inpic->p[Y_PLANE].p_pixels,
 668         p_outpic->p[Y_PLANE].i_lines * p_outpic->p[Y_PLANE].i_pitch );
 669     vlc_memcpy(
 670         p_outpic->p[U_PLANE].p_pixels, p_inpic->p[U_PLANE].p_pixels,
 671         p_outpic->p[U_PLANE].i_lines * p_outpic->p[U_PLANE].i_pitch );
 672     vlc_memcpy(
 673         p_outpic->p[V_PLANE].p_pixels, p_inpic->p[V_PLANE].p_pixels,
 674         p_outpic->p[V_PLANE].i_lines * p_outpic->p[V_PLANE].i_pitch );
 675
 676     GaussianConvolution( p_inpic, p_smooth );
 677
 678     /* Sobel gradient
 679
 680      | -1 0 1 |     |  1  2  1 |
 681      | -2 0 2 | and |  0  0  0 |
 682      | -1 0 1 |     | -1 -2 -1 | */
 683
 684     i_max = 0;
 685     i_rho_max = 0;
 686     i_phi_max = 0;
 687     for( y = 4; y < i_num_lines - 4; y++ )
 688     {
 689         for( x = 4; x < i_src_visible - 4; x++ )
 690         {
 691             uint32_t a =
 692             (
 693               abs(
 694                 ( ( p_smooth[(y-1)*i_src_visible+x]
 695                     - p_smooth[(y+1)*i_src_visible+x] ) <<1 )
 696                + ( p_smooth[(y-1)*i_src_visible+x-1]
 697                    - p_smooth[(y+1)*i_src_visible+x-1] )
 698                + ( p_smooth[(y-1)*i_src_visible+x+1]
 699                    - p_smooth[(y+1)*i_src_visible+x+1] )
 700               )
 701             +
 702               abs(
 703                 ( ( p_smooth[y*i_src_visible+x-1]
 704                     - p_smooth[y*i_src_visible+x+1] ) <<1 )
 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               )
 710             );
 711             if( a>>8 )
 712             {
 713                 for( i = 0 ; i < i_nb_steps ; i ++ )
 714                 {
 715                     i_rho = p_pre_hough[(i*i_num_lines+y)*i_src_visible + x];
 716                     if( p_hough[i_rho + i_diag/2 + i * i_diag]++ > i_max )
 717                     {
 718                         i_max = p_hough[i_rho + i_diag/2 + i * i_diag];
 719                         i_rho_max = i_rho;
 720                         i_phi_max = i;
 721                     }
 722                 }
 723             }
 724         }
 725     }
 726
 727     d_sin = sin(i_phi_max*d_step);
 728     d_cos = cos(i_phi_max*d_step);
 729     if( d_cos != 0 )
 730     {
 731         for( x = 0 ; x < i_src_visible ; x++ )
 732         {
 733             y = (i_rho_max - x * d_sin) / d_cos;
 734             if( y >= 0 && y < i_num_lines )
 735                 p_outpix[y*i_dst_pitch+x] = 255;
 736         }
 737     }
 738
 739     free( p_hough );
 740     free( p_smooth );
 741 }
 742 #undef p_pre_hough
 743
 744
 745 static int GradientCallback( vlc_object_t *p_this, char const *psz_var,
 746                              vlc_value_t oldval, vlc_value_t newval,
 747                              void *p_data )
 748 {
 749     VLC_UNUSED(oldval);
 750     filter_sys_t *p_sys = (filter_sys_t *)p_data;
 751     if( !strcmp( psz_var, FILTER_PREFIX "mode" ) )
 752     {
 753         if( !strcmp( newval.psz_string, "gradient" ) )
 754         {
 755             p_sys->i_mode = GRADIENT;
 756         }
 757         else if( !strcmp( newval.psz_string, "edge" ) )
 758         {
 759             p_sys->i_mode = EDGE;
 760         }
 761         else if( !strcmp( newval.psz_string, "hough" ) )
 762         {
 763             p_sys->i_mode = HOUGH;
 764         }
 765         else
 766         {
 767             msg_Err( p_this, "no valid gradient mode provided (%s)", newval.psz_string );
 768             p_sys->i_mode = GRADIENT;
 769         }
 770     }
 771     else if( !strcmp( psz_var, FILTER_PREFIX "type" ) )
 772     {
 773         p_sys->i_gradient_type = newval.i_int;
 774     }
 775     else if( !strcmp( psz_var, FILTER_PREFIX "cartoon" ) )
 776     {
 777         p_sys->b_cartoon = newval.b_bool;
 778     }
 779     return VLC_SUCCESS;
 780 }