// Copyright 2003 Matt Sandstršm/Too Much Too Soon
// This script is freeware, meaning you may copy and
// distribute it free of charge, as long as it's kept intact,
// including this message. Feel free to use the code as
// inspiration for your own scripts, but don't steal.
// Email me at mattias@beauty.se if you have any questions.
// Thank you. Have fun. 

filter "Shadow/Highlight Gamma";
group "TMTS Color";

input sg, "Shadow Gamma", slider, 1, 0.01, 4 detent 1;
input hg, "Highlight Gamma", slider, 1, 0.01, 4 detent 1;

InformationFlag("YUVaware")

code

float i, format, clut[256]

format = GetPixelFormat(dest)

repeat with i = 0 to 127
	clut[i] = power(i/127, sg)/2;
	clut[i+128] = power(i/127, hg)/2+0.5;
end repeat;

if (format != kFormatYUV219)
	ConvertImage(src1, src1, kFormatYUV219);
end if

levelMap(src1, dest, LinearRamp, clut, LinearRamp, LinearRamp);