static int
vips_scale_build( VipsObject *object )
{
VipsConversion *conversion = VIPS_CONVERSION( object );
VipsScale *scale = (VipsScale *) object;
VipsImage **t = (VipsImage **) vips_object_local_array( object, 7 );
double mx;
double mn;
if( VIPS_OBJECT_CLASS( vips_scale_parent_class )->build( object ) )
return( -1 );
if( vips_stats( scale->in, &t[0], NULL ) )
return( -1 );
mn = *VIPS_MATRIX( t[0], 0, 0 );
mx = *VIPS_MATRIX( t[0], 1, 0 );
if( mn == mx ) {
/* Range of zero: just return black.
*/
if( vips_black( &t[1], scale->in->Xsize, scale->in->Ysize,
"bands", scale->in->Bands,
NULL ) ||
vips_image_write( t[1], conversion->out ) )
return( -1 );
}
else if( scale->log ) {
double f = 255.0 / log10( 1.0 + pow( mx, scale->exp ) );
if( vips_pow_const1( scale->in, &t[2], scale->exp, NULL ) ||
vips_linear1( t[2], &t[3], 1.0, 1.0, NULL ) ||
vips_log10( t[3], &t[4], NULL ) ||
vips_linear1( t[4], &t[5], f, 0.0,
"uchar", TRUE,
NULL ) ||
vips_image_write( t[5], conversion->out ) )
return( -1 );
}
else {
double f = 255.0 / (mx - mn);
/* Add .5 to get round-to-nearest.
*/
double a = -(mn * f) + 0.5;
if( vips_linear1( scale->in, &t[2], f, a,
"uchar", TRUE,
NULL ) ||
vips_image_write( t[2], conversion->out ) )
return( -1 );
}
return( 0 );
}
/* Calculate sqrt(b1^2 + b2^2 ...)
*/
static int
pythagoras( VipsSmartcrop *smartcrop, VipsImage *in, VipsImage **out )
{
VipsImage **t = (VipsImage **)
vips_object_local_array( VIPS_OBJECT( smartcrop ),
2 * in->Bands + 1 );
int i;
for( i = 0; i < in->Bands; i++ )
if( vips_extract_band( in, &t[i], i, NULL ) )
return( -1 );
for( i = 0; i < in->Bands; i++ )
if( vips_multiply( t[i], t[i], &t[i + in->Bands], NULL ) )
return( -1 );
if( vips_sum( &t[in->Bands], &t[2 * in->Bands], in->Bands, NULL ) ||
vips_pow_const1( t[2 * in->Bands], out, 0.5, NULL ) )
return( -1 );
return( 0 );
}
