/**
* im_tone_analyse:
* @in: input image
* @out: output image
* @Ps: shadow point (eg. 0.2)
* @Pm: mid-tone point (eg. 0.5)
* @Ph: highlight point (eg. 0.8)
* @S: shadow adjustment (+/- 30)
* @M: mid-tone adjustment (+/- 30)
* @H: highlight adjustment (+/- 30)
*
* As im_tone_build(), but analyse the histogram of @in and use it to
* pick the 0.1% and 99.9% points for @Lb and @Lw.
*
* See also: im_tone_build().
*
* Returns: 0 on success, -1 on error
*/
int
im_tone_analyse(
IMAGE *in,
IMAGE *out,
double Ps, double Pm, double Ph,
double S, double M, double H )
{
IMAGE *t[4];
int low, high;
double Lb, Lw;
if( im_open_local_array( out, t, 4, "im_tone_map", "p" ) )
return( -1 );
/* If in is IM_CODING_LABQ, unpack.
*/
if( in->Coding == IM_CODING_LABQ ) {
if( im_LabQ2LabS( in, t[0] ) )
return( -1 );
}
else
t[0] = in;
/* Should now be 3-band short.
*/
if( im_check_uncoded( "im_tone_analyse", t[0] ) ||
im_check_bands( "im_tone_analyse", t[0], 3 ) ||
im_check_format( "im_tone_analyse", t[0], IM_BANDFMT_SHORT ) )
return( -1 );
if( im_extract_band( t[0], t[1], 0 ) ||
im_clip2fmt( t[1], t[2], IM_BANDFMT_USHORT ) ||
im_histgr( t[2], t[3], -1 ) )
return( -1 );
if( im_mpercent_hist( t[3], 0.1 / 100.0, &high ) ||
im_mpercent_hist( t[3], 99.9 / 100.0, &low ) )
return( -1 );
Lb = 100 * low / 32768;
Lw = 100 * high / 32768;
im_diag( "im_tone_analyse", "set Lb = %g, Lw = %g", Lb, Lw );
return( im_tone_build( out, Lb, Lw, Ps, Pm, Ph, S, M, H ) );
}
/**
* im_mpercent:
* @in: input image
* @percent: threshold percentage
* @out: output threshold value
*
* im_mpercent() returns (through the @out parameter) the threshold above
* which there are @percent values of @in. If for example percent=.1, the
* number of pels of the input image with values greater than the returned
* int will correspond to 10% of all pels of the image.
*
* The function works for uchar and ushort images only. It can be used
* to threshold the scaled result of a filtering operation.
*
* See also: im_histgr(), im_profile().
*
* Returns: 0 on success, -1 on error
*/
int
im_mpercent( IMAGE *in, double percent, int *out )
{
IMAGE *t;
if( !(t = im_open( "im_mpercent1", "p" )) )
return( -1 );
if( im_histgr( in, t, -1 ) ||
im_mpercent_hist( t, percent, out ) ) {
im_close( t );
return( -1 );
}
im_close( t );
return( 0 );
}
