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