Using color sampler values with curves adjustment layer

Question

Hi, I have just started trying to teach myself javascript.  Based on preliminary research, it's become apparent that there are many functions in Photoshop that are either extremely cumbersome or impossible to code by hand without using the Script Listener.
My  goal is as follows: first, I will manually load two photos as layers in a single document.  Then I will manually place two or more color sampler points on the document.  At this point I would like the script to create a curves adjustment layer (ideally clipped to layer 2) and place as individual channel anchor points  the RGB data from the color sampler points on Layer 2, and then adjust the output of the points on each channel to the color sampler RGB values of layer 1.  
As my first script, I realize this is probably going to be a lot of work.
I did find some code that returns the average value of manually placed color sampler points.  Conceptually then, I would need to add code which creates a new curves adjustment layer and adds those RGB values (from a specific layer)  as anchor points on the individual channels,  and then hides one layer and looks at the RGB values of the color sampler points, and uses them as the output values for each anchor point.
Sounds simple enough from a conceptual standpoint.
I'm looking for some guidance on how to get started.
Which parts will I definitely need Scriptlistener for and will that be adequate to do the job?
How would you recommend I get started on this?
Thanks very much for any input.

Answer 1

The function I had provided was an example into which you would need to feed the values you got with Mike’s code.
The code below would create a Curves Layer as shown in the screenshot, but I’m not sure it would work reasonably for all cases.
// with code by mike hale;
// 2012, use it at your own risk;
// call the function to run the script
#target photoshop
createCurveAdjustmetFromColorSamplers();
// create a function fo hold most of the code
function createCurveAdjustmetFromColorSamplers(){
    // first add some condition checks
    // needs an open document in a color mode that supports layers
    if(app.documents.length == 0 || ( app.activeDocument.mode == DocumentMode.BITMAP || app.activeDocument.mode == DocumentMode.INDEXEDCOLOR ) ){   
        alert('This script requires a document in Greyscale, RGB, CMYK, or Lab mode.');
        return;
    // check for at least two colorSamplers
    if(app.activeDocument.colorSamplers.length < 2 ){
        alert('This script requires at least two colorSamplers.');
        return;
    // last check for at least two layers - assume they will be on same level( not in layerSet )
    if(app.activeDocument.layers.length < 2 ){
        alert('This script requires at least two layers.');
        return;
    // create varaibles to hold the colorSampler's color property for each layer
    // for the bottom layer
    var outputArray = new Array();
    // for top layer - array could also be created this way
    var inputArray = [];
    // store the number of samples because it will be needed in more than one place
    var numberOfSamples = app.activeDocument.colorSamplers.length;
    // hide the top layer
    app.activeDocument.layers[0].visible = false;
    // collect the samples from the bottom layer
    for(var sampleIndex = 0; sampleIndex < numberOfSamples; sampleIndex++ ){
        outputArray.push(app.activeDocument.colorSamplers[sampleIndex].color);
    // turn the top layer back on
    app.activeDocument.layers[0].visible = true;
    // collect those samples
    for(var sampleIndex = 0; sampleIndex < numberOfSamples; sampleIndex++ ){
        inputArray.push(app.activeDocument.colorSamplers[sampleIndex].color);
    // make sure the top layer is the activeLayer
    app.activeDocument.activeLayer = app.activeDocument.layers[0];
// create arrays of the color values:
var theArray = [[0, 0, 0, 0, 0, 0]];
for (var m = 0; m < inputArray.length; m++) {
theArray.push([inputArray[m].rgb.red, outputArray[m].rgb.red, inputArray[m].rgb.green, outputArray[m].rgb.green, inputArray[m].rgb.blue, outputArray[m].rgb.blue]);
theArray.push([255, 255, 255, 255, 255, 255]);
// sort;
theArray.sort(sortArrayByIndexedItem);
// makeCurveAdjustmentLayer();
rgbCurvesLayer (theArray)
////// make rgb curves layer //////
function rgbCurvesLayer (theArray) {
// =======================================================
var idMk = charIDToTypeID( "Mk  " );
    var desc5 = new ActionDescriptor();
    var idnull = charIDToTypeID( "null" );
        var ref2 = new ActionReference();
        var idAdjL = charIDToTypeID( "AdjL" );
        ref2.putClass( idAdjL );
    desc5.putReference( idnull, ref2 );
    var idUsng = charIDToTypeID( "Usng" );
        var desc6 = new ActionDescriptor();
        var idType = charIDToTypeID( "Type" );
            var desc7 = new ActionDescriptor();
            var idpresetKind = stringIDToTypeID( "presetKind" );
            var idpresetKindType = stringIDToTypeID( "presetKindType" );
            var idpresetKindDefault = stringIDToTypeID( "presetKindDefault" );
            desc7.putEnumerated( idpresetKind, idpresetKindType, idpresetKindDefault );
        var idCrvs = charIDToTypeID( "Crvs" );
        desc6.putObject( idType, idCrvs, desc7 );
    var idAdjL = charIDToTypeID( "AdjL" );
    desc5.putObject( idUsng, idAdjL, desc6 );
executeAction( idMk, desc5, DialogModes.NO );
// =======================================================
var idsetd = charIDToTypeID( "setd" );
    var desc8 = new ActionDescriptor();
    var idnull = charIDToTypeID( "null" );
        var ref3 = new ActionReference();
        var idAdjL = charIDToTypeID( "AdjL" );
        var idOrdn = charIDToTypeID( "Ordn" );
        var idTrgt = charIDToTypeID( "Trgt" );
        ref3.putEnumerated( idAdjL, idOrdn, idTrgt );
    desc8.putReference( idnull, ref3 );
    var idT = charIDToTypeID( "T   " );
        var desc9 = new ActionDescriptor();
        var idpresetKind = stringIDToTypeID( "presetKind" );
        var idpresetKindType = stringIDToTypeID( "presetKindType" );
        var idpresetKindCustom = stringIDToTypeID( "presetKindCustom" );
        desc9.putEnumerated( idpresetKind, idpresetKindType, idpresetKindCustom );
        var idAdjs = charIDToTypeID( "Adjs" );
            var list1 = new ActionList();
                var desc10 = new ActionDescriptor();
                var idChnl = charIDToTypeID( "Chnl" );
                    var ref4 = new ActionReference();
                    var idChnl = charIDToTypeID( "Chnl" );
                    var idChnl = charIDToTypeID( "Chnl" );
                    var idRd = charIDToTypeID( "Rd  " );
                    ref4.putEnumerated( idChnl, idChnl, idRd );
                desc10.putReference( idChnl, ref4 );
                var idCrv = charIDToTypeID( "Crv " );
                    var list2 = new ActionList();
// add r points;
for (var m = 0; m < theArray.length; m++) {
          addCurvePoint (list2, theArray[m], 0)
                desc10.putList( idCrv, list2 );
            var idCrvA = charIDToTypeID( "CrvA" );
            list1.putObject( idCrvA, desc10 );
                var desc15 = new ActionDescriptor();
                var idChnl = charIDToTypeID( "Chnl" );
                    var ref5 = new ActionReference();
                    var idChnl = charIDToTypeID( "Chnl" );
                    var idChnl = charIDToTypeID( "Chnl" );
                    var idGrn = charIDToTypeID( "Grn " );
                    ref5.putEnumerated( idChnl, idChnl, idGrn );
                desc15.putReference( idChnl, ref5 );
                var idCrv = charIDToTypeID( "Crv " );
                    var list3 = new ActionList();
// add g points;
for (var m = 0; m < theArray.length; m++) {
          addCurvePoint (list3, theArray[m], 2)
                desc15.putList( idCrv, list3 );
            var idCrvA = charIDToTypeID( "CrvA" );
            list1.putObject( idCrvA, desc15 );
                var desc20 = new ActionDescriptor();
                var idChnl = charIDToTypeID( "Chnl" );
                    var ref6 = new ActionReference();
                    var idChnl = charIDToTypeID( "Chnl" );
                    var idChnl = charIDToTypeID( "Chnl" );
                    var idBl = charIDToTypeID( "Bl  " );
                    ref6.putEnumerated( idChnl, idChnl, idBl );
                desc20.putReference( idChnl, ref6 );
                var idCrv = charIDToTypeID( "Crv " );
                    var list4 = new ActionList();
// add b points;
for (var m = 0; m < theArray.length; m++) {
          addCurvePoint (list4, theArray[m], 4)
                desc20.putList( idCrv, list4 );
            var idCrvA = charIDToTypeID( "CrvA" );
            list1.putObject( idCrvA, desc20 );
        desc9.putList( idAdjs, list1 );
    var idCrvs = charIDToTypeID( "Crvs" );
    desc8.putObject( idT, idCrvs, desc9 );
executeAction( idsetd, desc8, DialogModes.NO );
return app.activeDocument.activeLayer;
////// add curve point //////
function addCurvePoint (theList, valueHor, theNumber) {
var desc11 = new ActionDescriptor();
var idHrzn = charIDToTypeID( "Hrzn" );
desc11.putDouble( idHrzn, valueHor[theNumber] );
var idVrtc = charIDToTypeID( "Vrtc" );
desc11.putDouble( idVrtc, valueHor[theNumber+1] );
var idPnt = charIDToTypeID( "Pnt " );
theList.putObject( idPnt, desc11 );
////// sort a double array, thanks to sam, http://www.rhinocerus.net/forum/lang-javascript/ //////
function sortArrayByIndexedItem(a,b) {
var theIndex = 0;
if (a[theIndex]<b[theIndex]) return -1;
if (a[theIndex]>b[theIndex]) return 1;
return 0;