{
	Create a calibration image using pcomb.
	Run through log scales in each primary and grey from 1/100 to 1.
	Creates eight rows of 10 color squares each.
	First two rows are greyscale.
	Next rows run through red, green, blue, magenta, yellow and cyan.
}
xres : 512;			{ settable x resolution }
yres : xres * .8;		{ for square patches }
gap : xres/128;			{ gap between patches }
pwidth : (xres-gap)/10 - gap;	{ patch width }
pheight : (yres-gap)/8 - gap;	{ patch height }
gapgrey : 1;			{ value for gap pixels }
minv : 0.01;			{ minimum value }
scale(x) : minv^(1-x);
or(a,b) : if( a, a, b );
and(a,b) : if( a, b, a );
mod(n,d) : n - floor(n/d)*d;

ingap = if(or(gap-mod(x,pwidth+gap),gap-mod(y,pheight+gap)), 1, -1);

ro = if(ingap, gapgrey, redval);
go = if(ingap, gapgrey, grnval);
bo = if(ingap, gapgrey, bluval);

{ Patches are numbered starting from 0 at the lower left, incr. right then up }

n = floor(x/(pwidth+gap)) + 10*floor(y/(pheight+gap));

redval = if(19.5-n, scale(n/19),
		select(floor((n-10)/10), scale((n-20)/9), 0, 0,
				scale((n-50)/9), scale((n-60)/9), 0));
grnval = if(19.5-n, scale(n/19),
		select(floor((n-10)/10), 0, scale((n-30)/9), 0,
				0, scale((n-60)/9), scale((n-70)/9)));
bluval = if(19.5-n, scale(n/19),
		select(floor((n-10)/10), 0, 0, scale((n-40)/9),
				scale((n-50)/9), 0, scale((n-70)/9)));