svg.c

VLC Player Source Code

    int channels_in;
    int alpha;
    picture_t *p_pic;
    subpicture_region_t *p_region_tmp;

    if ( p_filter->p_sys->i_width != i_width ||
         p_filter->p_sys->i_height != i_height )
    {
        svg_set_size( p_filter, i_width, i_height );
        p_svg->p_rendition = NULL;
    }

    if( p_svg->p_rendition == NULL ) {
        svg_RenderPicture( p_filter, p_svg );
        if( ! p_svg->p_rendition )
        {
            msg_Err( p_filter, "Cannot render SVG" );
            return VLC_EGENERIC;
        }
    }
    i_width = gdk_pixbuf_get_width( p_svg->p_rendition );
    i_height = gdk_pixbuf_get_height( p_svg->p_rendition );

    /* Create a new subpicture region */
    memset( &fmt, 0, sizeof( video_format_t ) );
    fmt.i_chroma = VLC_FOURCC( 'Y','U','V','A' );
    fmt.i_aspect = VOUT_ASPECT_FACTOR;
    fmt.i_width = fmt.i_visible_width = i_width;
    fmt.i_height = fmt.i_visible_height = i_height;
    fmt.i_x_offset = fmt.i_y_offset = 0;
    p_region_tmp = spu_CreateRegion( p_filter, &fmt );
    if( !p_region_tmp )
    {
        msg_Err( p_filter, "cannot allocate SPU region" );
        return VLC_EGENERIC;
    }
    p_region->fmt = p_region_tmp->fmt;
    p_region->picture = p_region_tmp->picture;
    free( p_region_tmp );

    p_region->i_x = p_region->i_y = 0;
    p_y = p_region->picture.Y_PIXELS;
    p_u = p_region->picture.U_PIXELS;
    p_v = p_region->picture.V_PIXELS;
    p_a = p_region->picture.A_PIXELS;

    i_pitch = p_region->picture.Y_PITCH;
    i_u_pitch = p_region->picture.U_PITCH;

    /* Initialize the region pixels (only the alpha will be changed later) */
    memset( p_y, 0x00, i_pitch * p_region->fmt.i_height );
    memset( p_u, 0x80, i_u_pitch * p_region->fmt.i_height );
    memset( p_v, 0x80, i_u_pitch * p_region->fmt.i_height );

    p_pic = &p_region->picture;

    /* Copy the data */

    /* This rendering code is in no way optimized. If someone has some time to
       make it work faster or better, please do.
    */

    /*
      p_pixbuf->get_rowstride() is the number of bytes in a line.
      p_pixbuf->get_height() is the number of lines.

      The number of bytes of p_pixbuf->p_pixels is get_rowstride * get_height

      if( has_alpha() ) {
      alpha = pixels [ n_channels * ( y*rowstride + x ) + 3 ];
      }
      red   = pixels [ n_channels * ( y*rowstride ) + x ) ];
      green = pixels [ n_channels * ( y*rowstride ) + x ) + 1 ];
      blue  = pixels [ n_channels * ( y*rowstride ) + x ) + 2 ];
    */

    pixels_in = gdk_pixbuf_get_pixels( p_svg->p_rendition );
    rowstride_in = gdk_pixbuf_get_rowstride( p_svg->p_rendition );
    channels_in = gdk_pixbuf_get_n_channels( p_svg->p_rendition );
    alpha = gdk_pixbuf_get_has_alpha( p_svg->p_rendition );

    /*
      This crashes the plugin (if !alpha). As there is always an alpha value,
      it does not matter for the moment :

    if( !alpha )
      memset( p_a, 0xFF, i_pitch * p_region->fmt.i_height );
    */

#define INDEX_IN( x, y ) ( y * rowstride_in + x * channels_in )
#define INDEX_OUT( x, y ) ( y * i_pitch + x * p_pic->p[Y_PLANE].i_pixel_pitch )

    for( y = 0; y < i_height; y++ )
    {
        for( x = 0; x < i_width; x++ )
        {
            guchar *p_in;
            int i_out;

            p_in = &pixels_in[INDEX_IN( x, y )];

#define R( pixel ) *pixel
#define G( pixel ) *( pixel+1 )
#define B( pixel ) *( pixel+2 )
#define ALPHA( pixel ) *( pixel+3 )

            /* From http://www.geocrawler.com/archives/3/8263/2001/6/0/6020594/ :
               Y = 0.29900 * R + 0.58700 * G + 0.11400 * B
               U = -0.1687 * r  - 0.3313 * g + 0.5 * b + 128
               V = 0.5   * r - 0.4187 * g - 0.0813 * b + 128
            */
            if ( alpha ) {
                i_out = INDEX_OUT( x, y );

                p_pic->Y_PIXELS[i_out] = .299 * R( p_in ) + .587 * G( p_in ) + .114 * B( p_in );

                p_pic->U_PIXELS[i_out] = -.1687 * R( p_in ) - .3313 * G( p_in ) + .5 * B( p_in ) + 128;
                p_pic->V_PIXELS[i_out] = .5 * R( p_in ) - .4187 * G( p_in ) - .0813 * B( p_in ) + 128;

                p_pic->A_PIXELS[i_out] = ALPHA( p_in );
            }
        }
    }

    return VLC_SUCCESS;
}

static void svg_set_size( filter_t *p_filter, int width, int height )
{
  p_filter->p_sys->i_width = width;
  p_filter->p_sys->i_height = height;
}

static void svg_SizeCallback( int *width, int *height, gpointer data )
{
    filter_t *p_filter = data;

    *width = p_filter->p_sys->i_width;
    *height = p_filter->p_sys->i_height;
    return;
}

static void svg_RenderPicture( filter_t *p_filter,
                               svg_rendition_t *p_svg )
{
    /* Render the SVG string p_string->psz_text into a new picture_t
       p_string->p_rendition with dimensions ( ->i_width, ->i_height ) */
    RsvgHandle *p_handle;
    GError *error = NULL;

    p_svg->p_rendition = NULL;

    p_handle = rsvg_handle_new();

    if( !p_handle )
    {
        msg_Err( p_filter, "Error creating SVG reader: %s", error->message );
        return;
    }

    rsvg_handle_set_size_callback( p_handle, svg_SizeCallback, p_filter, NULL );

    if( ! rsvg_handle_write( p_handle,
                 ( guchar* )p_svg->psz_text, strlen( p_svg->psz_text ),
                 &error ) )
    {
        msg_Err( p_filter, "error while rendering SVG: %s\n", error->message );
        g_object_unref( G_OBJECT( p_handle ) );
        return;
    }

    if( ! rsvg_handle_close( p_handle, &error ) )
    {
        msg_Err( p_filter, "error while rendering SVG (close): %s\n", error->message );
        g_object_unref( G_OBJECT( p_handle ) );
        return;
    }

    p_svg->p_rendition = rsvg_handle_get_pixbuf( p_handle );

    g_object_unref( G_OBJECT( p_handle ) );
}


static int RenderText( filter_t *p_filter, subpicture_region_t *p_region_out,
                       subpicture_region_t *p_region_in )
{
    filter_sys_t *p_sys = p_filter->p_sys;
    svg_rendition_t *p_svg = NULL;
    char *psz_string;

    /* Sanity check */
    if( !p_region_in || !p_region_out ) return VLC_EGENERIC;
    psz_string = p_region_in->psz_text;
    if( !psz_string || !*psz_string ) return VLC_EGENERIC;

    p_svg = ( svg_rendition_t * )malloc( sizeof( svg_rendition_t ) );
    if( !p_svg )
        return VLC_ENOMEM;

    p_region_out->i_x = p_region_in->i_x;
    p_region_out->i_y = p_region_in->i_y;

    /* Check if the data is SVG or pure text. In the latter case,
       convert the text to SVG. FIXME: find a better test */
    if( strstr( psz_string, "<svg" ))
    {
        /* Data is SVG: duplicate */
        p_svg->psz_text = strdup( psz_string );
        if( !p_svg->psz_text )
        {
            free( p_svg );
            return VLC_ENOMEM;
        }
    }
    else
    {
        /* Data is text. Convert to SVG */
        /* FIXME: handle p_style attributes */
        int length;
        char* psz_template = p_sys->psz_template;
        length = strlen( psz_string ) + strlen( psz_template ) + 42;
        p_svg->psz_text = malloc( ( length + 1 ) * sizeof( char ) );
        if( !p_svg->psz_text )
        {
            free( p_svg );
            return VLC_ENOMEM;
        }
        memset( p_svg->psz_text, 0, length + 1 );
        snprintf( p_svg->psz_text, length, psz_template, psz_string );
    }
    p_svg->i_width = p_sys->i_width;
    p_svg->i_height = p_sys->i_height;
    p_svg->i_chroma = VLC_FOURCC( 'Y','U','V','A' );

    /* Render the SVG.
       The input data is stored in the p_string structure,
       and the function updates the p_rendition attribute. */
    svg_RenderPicture( p_filter, p_svg );

    Render( p_filter, p_region_out, p_svg, p_svg->i_width, p_svg->i_height );
    FreeString( p_svg );

    return VLC_SUCCESS;
}

static void FreeString( svg_rendition_t *p_svg )
{
    free( p_svg->psz_text );
    /* p_svg->p_rendition is a GdkPixbuf, and its allocation is
       managed through ref. counting */
    if( p_svg->p_rendition )
        g_object_unref( p_svg->p_rendition );
    free( p_svg );
}