Photoshop CC eye dropper tool script - scripting

Question

I have a batch action to place a pure white background behind an image. I want to be able to select the color from a fixed pixel position on each photo. When I record the eye dropper in actions it only records the color i picked, not the action of picking the color. I have looked into scripting and tried various solutions on the web.
This is the script I have tried:
var docRef = app.activeDocument;
var pixelLoc = [32,42];
var colorSamplerRef = docRef.colorSamplers.add(pixelLoc);
app.foregroundColor = colorSamplerRef.color;
It doesn't perform the action I need though. Which is select - > color range -> eye dropper tool on fixed position

Answer 1

To achieve this you can create a custom function which invokes the Color Range generated selection, (named selectColorRange in the example gist below).
The selectColorRange function utilizes new ActionDescripter() to configure the properties, which are akin to the settings options shown in the dialog box when you manually choose Select -> Color Range from the Menu bar. This function is invoked after adding the colorSampler at a given x/y coordinate as follows:
selectColorRange(sampledColor, 80); // <-- Specify the fuzziness as required.
Note how we pass in the previous sampledColor value, and a fuzziness value of 80, (which is the default value used in Photoshop).
Example gist:
var docRef = app.activeDocument; // Assumes a document is active.
// Remove any Color Samplers that may already exist.
docRef.colorSamplers.removeAll();
// deselct any selection that may already exist.
docRef.selection.deselect();
// Get color sample from a given x,y coordinate.
var pixelLoc = [32,42];
var colorSampleRef = docRef.colorSamplers.add(pixelLoc);
var sampledColor = colorSampleRef.color;
// Set the foreground color to the sampled color.
app.foregroundColor = sampledColor;
/**
* Invokes and configures `Select > Color Range` from menu bar.
* #param {Object} color - The sampled color object.
* #param {Number} [fuzziness=80] - The Fuziness value (between 0-200).
*/
function selectColorRange(color, fuzziness) {
fuzziness = (typeof fuzziness !== 'undefined') ? fuzziness : 80;
var d1 = new ActionDescriptor();
// Set the amount of Fuzziness.
d1.putInteger(charIDToTypeID('Fzns'), fuzziness);
// Set invert option to false.
d1.putBoolean(charIDToTypeID('Invr'), false);
d1.putInteger(stringIDToTypeID('colorModel'), 0);
// Set the lAB value for Minimum.
var d2 = new ActionDescriptor();
d2.putDouble(charIDToTypeID('Lmnc'), color.lab.l);
d2.putDouble(charIDToTypeID('A '), color.lab.a);
d2.putDouble(charIDToTypeID('B '), color.lab.b);
d1.putObject(charIDToTypeID('Mnm '), charIDToTypeID('LbCl'), d2);
// Set the lAB value for Maximum.
var d3 = new ActionDescriptor();
d3.putDouble(charIDToTypeID('Lmnc'), color.lab.l);
d3.putDouble(charIDToTypeID('A '), color.lab.a);
d3.putDouble(charIDToTypeID('B '), color.lab.b);
d1.putObject(charIDToTypeID('Mxm '), charIDToTypeID('LbCl'), d3);
// Run the Color Range command without showing dialog.
executeAction(charIDToTypeID('ClrR'), d1, DialogModes.NO);
}
// Invoke the function passing in the sample
// color and default fuzziness value.
selectColorRange(sampledColor, 80);
//docRef.selection.clear();
//docRef.selection.fill(app.foregroundColor);
// Remove the Color Sampler.
colorSampleRef.remove();
Additional notes:
Photoshop allows a maximum of four color samplers to be added. If the document already included four color samplers then we'd get an error when attempting to add another one. To avoid the potential of this happening we invoke docRef.colorSamplers.removeAll(); to remove them all first.
Also, to ensure the resultant selection (i.e. the selection created after invoking the selectColorRange function), is not affected by any existing selection(s) we deselect them all first by invoking docRef.selection.deselect();
Finally, the color sampler that we initially added is removed by calling colorSampleRef.remove();
I'm unsure from your question what you intend to to with the selection once it's been created. As an example;
Lets say you wanted to clear the contents of the selection then you'd invoke docRef.selection.clear();.
If you wanted to fill the resultant selection with the previously sampled color then call docRef.selection.fill(app.foregroundColor);