How to fix layers offsets when exporting all Photoshop groups to .pngs in a javascript script?

Question

When I play the animation in photoshop, it looks fine. Every layer is in the correct position. When I run my script that saves each group to a png, the results have some layers offset.

I believe layers have weird issues with positions in animations. An image in a layer could have a different position in one frame and not another frame. I believe I'd have to get the script to step the frame in the animation to get the correct position, but I'm not sure how I would do that.

var set;
var layer;
var count = 0;
for(var i = 0; i < app.activeDocument.layerSets.length; i ++)
{
    set = app.activeDocument.layerSets[i];
    set.visible = false;
    count ++;
}
for(var i = 0; i < app.activeDocument.layerSets.length; i ++)
{
    set = app.activeDocument.layerSets[i];
    set.visible = true;

    // save
    var fileName = set.name.replace(/[\\\*\/\?:"\|<> ]/g,'');
    if(fileName.length ==0) fileName = "autoname";
    var handle = File(app.activeDocument.path + "/" + fileName + ".png");
    pngSaveOptions = new PNGSaveOptions();
    activeDocument.saveAs(handle, pngSaveOptions, true, Extension.LOWERCASE);

    set.visible = false;
}

alert("Saved " + count + " images.");

The correct animation plays in photoshop. The resulting .pngs are incorrect. https://imgur.com/a/y9PLPUX

Answer 1

If your animation is already in Photoshop timeline, maybe it's easier just to render the animation to frames? Go to File > Export > Render Video..., Chose Photoshop Image Sequence as a renderer, PNG as a format and in Render Options don't forget to select Straight Alpha Channel. This will render all frames to PNGs with transparency.

Answer 2

Figured it out. This script has a function that can go to another frame in the animation. I use it to render all sub-groups of the animation to their own separate .pngs

var set;
var layer;

for(var docI = 0; docI < app.documents.length; docI ++) {
    var doc = app.documents[docI];
    for (var frameIndex = 1; frameIndex <= 8; frameIndex++) {
        goToFrame(frameIndex);
        for (var i = 0; i < doc.layerSets.length; i++) {
            set = doc.layerSets[i];
            if (set.visible) {
                for (var setI = 0; setI < set.layerSets.length; setI++) {
                    var innerSet = set.layerSets[setI];
                    innerSet.visible = false;
                }
                for (var setI = 0; setI < set.layerSets.length; setI++) {
                    var innerSet = set.layerSets[setI];
                    innerSet.visible = true;
                    var fileName = innerSet.name.replace(/[\\\*\/\?:"\|<> ]/g, '');
                    if (fileName.length == 0) fileName = "autoname";
                    var handle = File(doc.path + "/output/" + doc.name.replace("player", fileName).replace(".psd", '') + (doc.layerSets.length - i) + ".png");
                    pngSaveOptions = new PNGSaveOptions();
                    activeDocument.saveAs(handle, pngSaveOptions, true, Extension.LOWERCASE);
                    innerSet.visible = false;
                }

            }
        }
    }
}

alert("Saved images.");

function goToFrame(index) {
    var jumpToFrameNumber = index; // counts from 1

    var desc = new ActionDescriptor();
    var ref1 = new ActionReference();
    ref1.putIndex( stringIDToTypeID( "animationFrameClass" ), jumpToFrameNumber );
    desc.putReference( charIDToTypeID( "null" ), ref1 );
    executeAction( charIDToTypeID( "slct" ), desc, DialogModes.NO );
}