#@gui CubeHelix: fx_cubehelix, fx_cubehelix_preview(1)
#@gui : Start colour = color(0,0,0)
#@gui : End colour = color(255,255,255)
#@gui : Start hue = float(1,0,3)
#@gui : Rotations = float(-1.5,-20,20)
#@gui : Saturation = float(1,0,5)
#@gui : Gamma = float(1,0,5)
#@gui : Normalise = bool(0)
#@gui : sep = separator(), Preview type = choice("Full","Forward horizontal","Forward vertical","Backward horizontal","Backward vertical","Duplicate top","Duplicate left","Duplicate bottom","Duplicate right","Duplicate horizontal","Duplicate vertical","Checkered","Checkered inverse"), Preview split = point(50,50,0,0,200,200,200,0,10,0)
fx_cubehelix :

to_gray to_rgb abs c 0,255 *. {1/255}
f "angle=(2*pi*(($7/3)+1+$8*I));fract=(I^$10);amp=($9*fract*(1-fract)/2);
((([${1-3}]+(fract*([${4-6}]-[${1-3}])))/255)+amp*[-0.14861*cos(angle[0])+1.78277*sin(angle[0]),-0.29227*cos(angle[1])-0.90649*sin(angle[1]),1.97294*cos(angle[2])])"
c 0,1
*. 255
if $11 n 0,255 fi
fx_cubehelix_preview :
gui_split_preview "fx_cubehelix $*",${-3--1}