/**
* im_scaleps:
* @in: input image
* @out: output image
*
* Scale a power spectrum. Transform with log10(1.0 + pow(x, 0.25)) + .5,
* then scale so max == 255.
*
* See also: im_scale().
*
* Returns: 0 on success, -1 on error
*/
int
im_scaleps( IMAGE *in, IMAGE *out )
{
IMAGE *t[4];
double mx;
double scale;
if( im_open_local_array( out, t, 4, "im_scaleps-1", "p" ) ||
im_max( in, &mx ) )
return( -1 );
if( mx <= 0.0 )
/* Range of zero: just return black.
*/
return( im_black( out, in->Xsize, in->Ysize, in->Bands ) );
scale = 255.0 / log10( 1.0 + pow( mx, .25 ) );
/* Transform!
*/
if( im_powtra( in, t[0], 0.25 ) ||
im_lintra( 1.0, t[0], 1.0, t[1] ) ||
im_log10tra( t[1], t[2] ) ||
im_lintra( scale, t[2], 0.0, t[3] ) ||
im_clip2fmt( t[3], out, IM_BANDFMT_UCHAR ) )
return( -1 );
return( 0 );
}
/**
* im_gammacorrect:
* @in: input image
* @out: output image
* @exponent: gamma factor
*
* Gamma-correct an 8- or 16-bit unsigned image with a lookup table. The
* output format is the same as the input format.
*
* See also: im_identity(), im_powtra(), im_maplut()
*
* Returns: 0 on success, -1 on error
*/
int
im_gammacorrect( IMAGE *in, IMAGE *out, double exponent )
{
IMAGE *t[4];
double mx1, mx2;
if( im_open_local_array( out, t, 4, "im_gammacorrect", "p" ) ||
im_check_u8or16( "im_gammacorrect", in ) ||
im_piocheck( in, out ) ||
(in->BandFmt == IM_BANDFMT_UCHAR ?
im_identity( t[0], 1 ) :
im_identity_ushort( t[0], 1, 65536 )) ||
im_powtra( t[0], t[1], exponent ) ||
im_max( t[0], &mx1 ) ||
im_max( t[1], &mx2 ) ||
im_lintra( mx1 / mx2, t[1], 0, t[2] ) ||
im_clip2fmt( t[2], t[3], in->BandFmt ) ||
im_maplut( in, out, t[3] ) )
return( -1 );
return( 0 );
}
/* Plot image.
*/
static int
plot( IMAGE *in, IMAGE *out )
{
double max;
int tsize;
int xsize;
int ysize;
if( im_incheck( in ) ||
im_poutcheck( out ) )
return( -1 );
/* Find range we will plot.
*/
if( im_max( in, &max ) )
return( -1 );
g_assert( max >= 0 );
if( in->BandFmt == IM_BANDFMT_UCHAR )
tsize = 256;
else
tsize = ceil( max );
/* Make sure we don't make a zero height image.
*/
if( tsize == 0 )
tsize = 1;
if( in->Xsize == 1 ) {
/* Vertical graph.
*/
xsize = tsize;
ysize = in->Ysize;
}
else {
/* Horizontal graph.
*/
xsize = in->Xsize;
ysize = tsize;
}
/* Set image.
*/
im_initdesc( out, xsize, ysize, in->Bands,
IM_BBITS_BYTE, IM_BANDFMT_UCHAR,
IM_CODING_NONE, IM_TYPE_HISTOGRAM, 1.0, 1.0, 0, 0 );
/* Set hints - ANY is ok with us.
*/
if( im_demand_hint( out, IM_ANY, NULL ) )
return( -1 );
/* Generate image.
*/
if( in->Xsize == 1 ) {
if( im_generate( out, NULL, make_vert_gen, NULL, in, NULL ) )
return( -1 );
}
else {
if( im_generate( out, NULL, make_horz_gen, NULL, in, NULL ) )
return( -1 );
}
return( 0 );
}
