Tall Merge PSDs

tall-merge-psd.js

const ZERO = new UnitValue(0, 'px')

function appendToDoc(dstDoc, fileRef, isFirstDoc) {
    const srcDoc = app.open(fileRef, undefined, true);
    superSelect()
    superCopy()

    const dstDocWidth = new UnitValue(dstDoc.width.as('px') < srcDoc.width.as('px') ? srcDoc.width.as('px') : dstDoc.width.as('px'), 'px')
    const dstDocHeight = new UnitValue(isFirstDoc ? srcDoc.height.as('px') : dstDoc.height.as('px') + srcDoc.height.as('px'), 'px')
    const pasteTopLeftRightBottom = isFirstDoc ? [ZERO, ZERO, dstDocWidth, dstDocHeight] : [new UnitValue(dstDoc.height.as('px'), 'px'), ZERO, dstDocWidth, dstDocHeight]

    srcDoc.close(SaveOptions.DONOTSAVECHANGES)

    app.activeDocument = dstDoc
    dstDoc.resizeCanvas(dstDocWidth, dstDocHeight, AnchorPosition.TOPCENTER);

    selectRect(pasteTopLeftRightBottom[0], pasteTopLeftRightBottom[1], pasteTopLeftRightBottom[2], pasteTopLeftRightBottom[3])
    superPaste()

}

function selectRect(top, left, right, bottom) {
    app.activeDocument.selection.select(Array(
        Array(left, top),
        Array(right, top),
        Array(right, bottom),
        Array(left, bottom)
    ), SelectionType.REPLACE)
}

function superSelect() {
    var idselectAllLayers = stringIDToTypeID("selectAllLayers");
    var desc40 = new ActionDescriptor();
    var idnull = charIDToTypeID("null");
    var ref19 = new ActionReference();
    var idLyr = charIDToTypeID("Lyr ");
    var idOrdn = charIDToTypeID("Ordn");
    var idTrgt = charIDToTypeID("Trgt");
    ref19.putEnumerated(idLyr, idOrdn, idTrgt);
    desc40.putReference(idnull, ref19);
    executeAction(idselectAllLayers, desc40, DialogModes.NO);
}

function superCopy() {
    var idcopy = charIDToTypeID("copy");
    executeAction(idcopy, undefined, DialogModes.NO);
}

function superPaste() {
    var idpast = charIDToTypeID("past");
    executeAction(idpast, undefined, DialogModes.NO);
}

const dstDoc = app.documents.add(10, 10, 300, "docRef", NewDocumentMode.RGB)
const fileList = File.openDialog("Select files to merge", "*.psd", true)

for (var i = 0; i < fileList.length; i++) {
    appendToDoc(dstDoc, fileList[i], i == 0)
}