gradient.c

VLC Player Source Code

                    - p_smooth[y*i_src_visible+x+1] ) <<1 )     \
               + ( p_smooth[(y+1)*i_src_visible+x-1]            \
                   - p_smooth[(y+1)*i_src_visible+x+1] )        \
              )                                                 \
            );
    if( p_filter->p_sys->i_gradient_type )
    {
        if( p_filter->p_sys->b_cartoon )
        {
            FOR
            if( a > 60 )
            {
                p_outpix[y*i_dst_pitch+x] = 0x00;
            }
            else
            {
                if( p_smooth[y*i_src_visible+x] > 0xa0 )
                    p_outpix[y*i_dst_pitch+x] =
                        0xff - ((0xff - p_inpix[y*i_src_pitch+x] )>>2);
                else if( p_smooth[y*i_src_visible+x] > 0x70 )
                    p_outpix[y*i_dst_pitch+x] =
                        0xa0 - ((0xa0 - p_inpix[y*i_src_pitch+x] )>>2);
                else if( p_smooth[y*i_src_visible+x] > 0x28 )
                    p_outpix[y*i_dst_pitch+x] =
                        0x70 - ((0x70 - p_inpix[y*i_src_pitch+x] )>>2);
                else
                    p_outpix[y*i_dst_pitch+x] =
                        0x28 - ((0x28 - p_inpix[y*i_src_pitch+x] )>>2);
            }
            }}
        }
        else
        {
            FOR
            p_outpix[y*i_dst_pitch+x] = clip_uint8_vlc( a );
            }}
        }
    }
    else
    {
        FOR
        if( a>>8 )
            p_outpix[y*i_dst_pitch+x] = 0;
        else
            p_outpix[y*i_dst_pitch+x] = 0xff-(uint8_t)a;
        }}
    }
#undef FOR
}

/*****************************************************************************
 * FilterEdge: Canny edge detection algorithm
 *****************************************************************************
 * http://fourier.eng.hmc.edu/e161/lectures/canny/node1.html
 * (well ... my implementation isn't really the canny algorithm ... but some
 * ideas are the same)
 *****************************************************************************/
/* angle : | */
#define THETA_Y 0
/* angle : - */
#define THETA_X 1
/* angle : / */
#define THETA_P 2
/* angle : \ */
#define THETA_M 3
static void FilterEdge( filter_t *p_filter, picture_t *p_inpic,
                                            picture_t *p_outpic )
{
    int x, y;

    const int i_src_pitch = p_inpic->p[Y_PLANE].i_pitch;
    const int i_src_visible = p_inpic->p[Y_PLANE].i_visible_pitch;
    const int i_dst_pitch = p_outpic->p[Y_PLANE].i_pitch;
    const int i_num_lines = p_inpic->p[Y_PLANE].i_visible_lines;

    const uint8_t *p_inpix = p_inpic->p[Y_PLANE].p_pixels;
    uint8_t *p_outpix = p_outpic->p[Y_PLANE].p_pixels;

    uint32_t *p_smooth;
    uint32_t *p_grad;
    uint8_t *p_theta;

    if( !p_filter->p_sys->p_buf32 )
        p_filter->p_sys->p_buf32 =
        (uint32_t *)malloc( i_num_lines * i_src_visible * sizeof(uint32_t));
    p_smooth = p_filter->p_sys->p_buf32;

    if( !p_filter->p_sys->p_buf32_bis )
        p_filter->p_sys->p_buf32_bis =
        (uint32_t *)malloc( i_num_lines * i_src_visible * sizeof(uint32_t));
    p_grad = p_filter->p_sys->p_buf32_bis;

    if( !p_filter->p_sys->p_buf8 )
        p_filter->p_sys->p_buf8 =
        (uint8_t *)malloc( i_num_lines * i_src_visible * sizeof(uint8_t));
    p_theta = p_filter->p_sys->p_buf8;

    if( !p_smooth || !p_grad || !p_theta ) return;

    if( p_filter->p_sys->b_cartoon )
    {
        vlc_memcpy( p_outpic->p[U_PLANE].p_pixels,
            p_inpic->p[U_PLANE].p_pixels,
            p_outpic->p[U_PLANE].i_lines * p_outpic->p[U_PLANE].i_pitch );
        vlc_memcpy( p_outpic->p[V_PLANE].p_pixels,
            p_inpic->p[V_PLANE].p_pixels,
            p_outpic->p[V_PLANE].i_lines * p_outpic->p[V_PLANE].i_pitch );
    }
    else
    {
        vlc_memset( p_outpic->p[Y_PLANE].p_pixels, 0xff,
              p_outpic->p[Y_PLANE].i_lines * p_outpic->p[Y_PLANE].i_pitch );
        vlc_memset( p_outpic->p[U_PLANE].p_pixels, 0x80,
            p_outpic->p[U_PLANE].i_lines * p_outpic->p[U_PLANE].i_pitch );
        vlc_memset( p_outpic->p[V_PLANE].p_pixels, 0x80,
            p_outpic->p[V_PLANE].i_lines * p_outpic->p[V_PLANE].i_pitch );
    }

    GaussianConvolution( p_inpic, p_smooth );

    /* Sobel gradient

     | -1 0 1 |     |  1  2  1 |
     | -2 0 2 | and |  0  0  0 |
     | -1 0 1 |     | -1 -2 -1 | */

    for( y = 1; y < i_num_lines - 1; y++ )
    {
        for( x = 1; x < i_src_visible - 1; x++ )
        {

            const int gradx =
                 ( p_smooth[(y-1)*i_src_visible+x-1]
                   - p_smooth[(y+1)*i_src_visible+x-1] )
               + ( ( p_smooth[(y-1)*i_src_visible+x]
                    - p_smooth[(y+1)*i_src_visible+x] ) <<1 )
               + ( p_smooth[(y-1)*i_src_visible+x+1]
                   - p_smooth[(y+1)*i_src_visible+x+1] );
            const int grady =
                 ( p_smooth[(y-1)*i_src_visible+x-1]
                   - p_smooth[(y-1)*i_src_visible+x+1] )
               + ( ( p_smooth[y*i_src_visible+x-1]
                    - p_smooth[y*i_src_visible+x+1] ) <<1 )
               + ( p_smooth[(y+1)*i_src_visible+x-1]
                   - p_smooth[(y+1)*i_src_visible+x+1] );

            p_grad[y*i_src_visible+x] = (uint32_t)(abs( gradx ) + abs( grady ));

            /* tan( 22.5 ) = 0,414213562 .. * 128 = 53
             * tan( 26,565051177 ) = 0.5
             * tan( 45 + 22.5 ) = 2,414213562 .. * 128 = 309
             * tan( 63,434948823 ) 2 */
            if( (grady<<1) > gradx )
                p_theta[y*i_src_visible+x] = THETA_P;
            else if( (grady<<1) < -gradx )
                p_theta[y*i_src_visible+x] = THETA_M;
            else if( !gradx || abs(grady) > abs(gradx)<<1 )
                p_theta[y*i_src_visible+x] = THETA_Y;
            else
                p_theta[y*i_src_visible+x] = THETA_X;
        }
    }

    /* edge computing */
    for( y = 1; y < i_num_lines - 1; y++ )
    {
        for( x = 1; x < i_src_visible - 1; x++ )
        {
            if( p_grad[y*i_src_visible+x] > 40 )
            {
                switch( p_theta[y*i_src_visible+x] )
                {
                    case THETA_Y:
                        if(    p_grad[y*i_src_visible+x] > p_grad[(y-1)*i_src_visible+x]
                            && p_grad[y*i_src_visible+x] > p_grad[(y+1)*i_src_visible+x] )
                        {
                            p_outpix[y*i_dst_pitch+x] = 0;
                            break;
                        } else goto colorize;
                    case THETA_P:
                        if(    p_grad[y*i_src_visible+x] > p_grad[(y-1)*i_src_visible+x-1]
                            && p_grad[y*i_src_visible+x] > p_grad[(y+1)*i_src_visible+x+1] )
                        {
                            p_outpix[y*i_dst_pitch+x] = 0;
                            break;
                        } else goto colorize;
                    case THETA_M:
                        if(    p_grad[y*i_src_visible+x] > p_grad[(y-1)*i_src_visible+x+1]
                            && p_grad[y*i_src_visible+x] > p_grad[(y+1)*i_src_visible+x-1] )
                        {
                            p_outpix[y*i_dst_pitch+x] = 0;
                            break;
                        } else goto colorize;
                    case THETA_X:
                        if(    p_grad[y*i_src_visible+x] > p_grad[y*i_src_visible+x-1]
                            && p_grad[y*i_src_visible+x] > p_grad[y*i_src_visible+x+1] )
                        {
                            p_outpix[y*i_dst_pitch+x] = 0;
                            break;
                        } else goto colorize;
                }
            }
            else
            {
                colorize:
                if( p_filter->p_sys->b_cartoon )
                {
                    if( p_smooth[y*i_src_visible+x] > 0xa0 )
                        p_outpix[y*i_dst_pitch+x] = (uint8_t)
                            0xff - ((0xff - p_inpix[y*i_src_pitch+x] )>>2);
                    else if( p_smooth[y*i_src_visible+x] > 0x70 )
                        p_outpix[y*i_dst_pitch+x] =(uint8_t)
                            0xa0 - ((0xa0 - p_inpix[y*i_src_pitch+x] )>>2);
                    else if( p_smooth[y*i_src_visible+x] > 0x28 )
                        p_outpix[y*i_dst_pitch+x] =(uint8_t)
                            0x70 - ((0x70 - p_inpix[y*i_src_pitch+x] )>>2);
                    else
                        p_outpix[y*i_dst_pitch+x] =(uint8_t)
                            0x28 - ((0x28 - p_inpix[y*i_src_pitch+x] )>>2);
                }
            }
        }
    }
}

/*****************************************************************************
 * FilterHough
 *****************************************************************************/
#define p_pre_hough p_filter->p_sys->p_pre_hough
static void FilterHough( filter_t *p_filter, picture_t *p_inpic,
                                             picture_t *p_outpic )
{
    int x, y, i;
    int i_src_visible = p_inpic->p[Y_PLANE].i_visible_pitch;
    int i_dst_pitch = p_outpic->p[Y_PLANE].i_pitch;
    int i_num_lines = p_inpic->p[Y_PLANE].i_visible_lines;

    uint8_t *p_outpix = p_outpic->p[Y_PLANE].p_pixels;

    int i_diag = sqrt( i_num_lines * i_num_lines +
                        i_src_visible * i_src_visible);
    int i_max, i_phi_max, i_rho, i_rho_max;
    int i_nb_steps = 90;
    double d_step = M_PI / i_nb_steps;
    double d_sin;
    double d_cos;
    uint32_t *p_smooth;
    int *p_hough = malloc( i_diag * i_nb_steps * sizeof(int) );
    if( ! p_hough ) return;
    p_smooth = (uint32_t *)malloc( i_num_lines*i_src_visible*sizeof(uint32_t));
    if( !p_smooth ) return;

    if( ! p_pre_hough )
    {
        msg_Dbg(p_filter, "Starting precalculation");
        p_pre_hough = malloc( i_num_lines*i_src_visible*i_nb_steps*sizeof(int));
        if( ! p_pre_hough ) return;
        for( i = 0 ; i < i_nb_steps ; i++)
        {
            d_sin = sin(d_step * i);
            d_cos = cos(d_step * i);
            for( y = 0 ; y < i_num_lines ; y++ )
                for( x = 0 ; x < i_src_visible ; x++ )
                {
                    p_pre_hough[(i*i_num_lines+y)*i_src_visible + x] =
                        ceil(x*d_sin + y*d_cos);
                }
        }
        msg_Dbg(p_filter, "Precalculation done");
    }

    vlc_memset( p_hough, 0, i_diag * i_nb_steps * sizeof(int) );

    vlc_memcpy(
        p_outpic->p[Y_PLANE].p_pixels, p_inpic->p[Y_PLANE].p_pixels,
        p_outpic->p[Y_PLANE].i_lines * p_outpic->p[Y_PLANE].i_pitch );
    vlc_memcpy(
        p_outpic->p[U_PLANE].p_pixels, p_inpic->p[U_PLANE].p_pixels,
        p_outpic->p[U_PLANE].i_lines * p_outpic->p[U_PLANE].i_pitch );
    vlc_memcpy(
        p_outpic->p[V_PLANE].p_pixels, p_inpic->p[V_PLANE].p_pixels,
        p_outpic->p[V_PLANE].i_lines * p_outpic->p[V_PLANE].i_pitch );

    GaussianConvolution( p_inpic, p_smooth );

    /* Sobel gradient

     | -1 0 1 |     |  1  2  1 |
     | -2 0 2 | and |  0  0  0 |
     | -1 0 1 |     | -1 -2 -1 | */

    i_max = 0;
    i_rho_max = 0;
    i_phi_max = 0;
    for( y = 4; y < i_num_lines - 4; y++ )
    {
        for( x = 4; x < i_src_visible - 4; x++ )
        {
            uint32_t a =
            (
              abs(
                ( ( p_smooth[(y-1)*i_src_visible+x]
                    - p_smooth[(y+1)*i_src_visible+x] ) <<1 )
               + ( p_smooth[(y-1)*i_src_visible+x-1]
                   - p_smooth[(y+1)*i_src_visible+x-1] )
               + ( p_smooth[(y-1)*i_src_visible+x+1]
                   - p_smooth[(y+1)*i_src_visible+x+1] )
              )
            +
              abs(
                ( ( p_smooth[y*i_src_visible+x-1]
                    - p_smooth[y*i_src_visible+x+1] ) <<1 )
               + ( p_smooth[(y-1)*i_src_visible+x-1]
                   - p_smooth[(y-1)*i_src_visible+x+1] )
               + ( p_smooth[(y+1)*i_src_visible+x-1]
                   - p_smooth[(y+1)*i_src_visible+x+1] )
              )
            );
            if( a>>8 )
            {
                for( i = 0 ; i < i_nb_steps ; i ++ )
                {
                    i_rho = p_pre_hough[(i*i_num_lines+y)*i_src_visible + x];
                    if( p_hough[i_rho + i_diag/2 + i * i_diag]++ > i_max )
                    {
                        i_max = p_hough[i_rho + i_diag/2 + i * i_diag];
                        i_rho_max = i_rho;
                        i_phi_max = i;
                    }
                }
            }
        }
    }

    d_sin = sin(i_phi_max*d_step);
    d_cos = cos(i_phi_max*d_step);
    if( d_cos != 0 )
    {
        for( x = 0 ; x < i_src_visible ; x++ )
        {
            y = (i_rho_max - x * d_sin) / d_cos;
            if( y >= 0 && y < i_num_lines )
                p_outpix[y*i_dst_pitch+x] = 255;
        }
    }

    free( p_hough );
    free( p_smooth );
}
#undef p_pre_hough


static int GradientCallback( vlc_object_t *p_this, char const *psz_var,
                             vlc_value_t oldval, vlc_value_t newval,
                             void *p_data )
{
    VLC_UNUSED(oldval);
    filter_sys_t *p_sys = (filter_sys_t *)p_data;
    if( !strcmp( psz_var, FILTER_PREFIX "mode" ) )
    {
        if( !strcmp( newval.psz_string, "gradient" ) )
        {
            p_sys->i_mode = GRADIENT;
        }
        else if( !strcmp( newval.psz_string, "edge" ) )
        {
            p_sys->i_mode = EDGE;
        }
        else if( !strcmp( newval.psz_string, "hough" ) )
        {
            p_sys->i_mode = HOUGH;
        }
        else
        {
            msg_Err( p_this, "no valid gradient mode provided (%s)", newval.psz_string );
            p_sys->i_mode = GRADIENT;
        }
    }
    else if( !strcmp( psz_var, FILTER_PREFIX "type" ) )
    {
        p_sys->i_gradient_type = newval.i_int;
    }
    else if( !strcmp( psz_var, FILTER_PREFIX "cartoon" ) )
    {
        p_sys->b_cartoon = newval.b_bool;
    }
    return VLC_SUCCESS;
}