gamma adjustment on LUTs with cursor

gamma_LUT.groovy

//Kevin Terretaz 061021
import ij.*
import ij.gui.*
import ij.process.*
import java.awt.image.*

// gammaLUT avec curseur
//possible pour les hyperstacks d'ajuster autant de curseurs que de channels en même temps?
imp = IJ.getImage()
luts = new LUT[0]
luts = imp.getLuts()
 */
imp = IJ.getImage()
ip = imp.getProcessor()
if (imp.isComposite())	original_lut = imp.getChannelLut()
else 										original_lut = ip.getColorModel()

//Dialog
gd = new GenericDialog("Gamma LUT Adjuster")
gd.addSlider("Gamma:", 0.05, 3.0, 1)
gd.addDialogListener(new DialogListener() {
	boolean dialogItemChanged(GenericDialog gd,java.awt.AWTEvent e) {
		gamma = gd.getNextNumber()
		applyLUT(original_lut)
		gammaLUT(gamma)
return true
	}
})
gd.showDialog()

if (gd.wasCanceled()) {
	applyLUT(original_lut)
	imp.updateAndDraw()
}

def gammaLUT(gamma){
	imp = IJ.getImage()
	ip = imp.getProcessor()
	//get colormodel aka lut
	if (imp.isComposite())	cm = imp.getChannelLut()
	else 										cm = ip.getColorModel()
	//get reds greens and blues as byte arrays
	reds		= new byte[256]
	greens	= new byte[256]
	blues		= new byte[256]
	cm.getReds(reds)
	cm.getGreens(greens)
	cm.getBlues(blues)
	//apply gamma on LUT arrays
	float_Gam = new float[256]
	int_Gam 	= new int [256]
	newReds 	= new byte[256]
	newGreens = new byte[256]
	newBlues 	= new byte[256]
	for (i=0; i<256; i++) float_Gam[i] = Math.pow(i, gamma)
	
	scale = 255/float_Gam[255]
	
	for (i=0; i<256; i++) int_Gam[i] = Math.round(float_Gam[i] * scale)
	
	for (i=0; i<256; i++) {
		j = int_Gam[i];
		newReds  [i]	= reds  [j]
		newGreens[i]	= greens[j]
		newBlues [i]	= blues [j]
	}
	//create new gammaLUT and apply
	lut = new LUT(8, 256,newReds,newGreens,newBlues)
	applyLUT(lut)
	imp.updateAndDraw()
}

def applyLUT(lut){
	if	(imp.isComposite())	imp.setChannelLut(lut)
	else					ip.setColorModel(lut)
}