Scale To Pixel.jsx

/**
 * Scale layer(s) to a specific pixel width and height
 * through a simple UI.
 *
 * @author github.com/ilovedoumiao
 * @version 1.0
 * @version 1.1 - Improved aspect-ratio-aware sizing, exact width/height scaling, keyed and 3D layer support + safer layer handling.
 */
 function showui() {
    var e = app.project.activeItem;
    if (!(e instanceof CompItem) || 0 === e.selectedLayers.length) {
        alert("Select layer(s) first.");
        return
    }
    var t = new Window("dialog", "Scale Layers"),
        a = t.add("group");
    a.orientation = "row", a.alignment = "left", a.add("statictext", void 0, "Enter 0 for no change");
    var i = t.add("group");
    i.orientation = "row", i.alignment = "left", i.add("statictext", void 0, "Width (px):");
    var $ = i.add("edittext", void 0, "0");
    $.characters = 10;
    var l = t.add("group");
    l.orientation = "row", l.alignment = "left", l.add("statictext", void 0, "Height (px):");
    var r = l.add("edittext", void 0, "0");
    r.characters = 10;
    var o = t.add("group");
    o.alignment = "center";
    var c = o.add("button", void 0, "OK"),
        n = o.add("button", void 0, "Cancel");
    c.onClick = function() {
        var e = parseFloat($.text),
            a = parseFloat(r.text);
        scalelayers(e, a), t.close()
    }, n.onClick = function() {
        t.close()
    }, t.center(), t.show()
}

function calculatePixelScale(e, t, a, i, $) {
    for (var l = [], r = 0; r < $.length; r++) l[r] = $[r];
    return a > 0 && i > 0 ? (l[0] = a / e * 100, l[1] = i / t * 100) : a > 0 ? (l[0] = a / e * 100, l[1] = l[0]) : i > 0 && (l[1] = i / t * 100, l[0] = l[1]), l
}

function verifyScaleToPixelCalculation() {
    var e = calculatePixelScale(200, 100, 100, 0, [100, 100, 75]),
        t = calculatePixelScale(200, 100, 100, 100, [100, 100, 75]);
    if (50 !== e[0] || 50 !== e[1] || 75 !== e[2] || 50 !== t[0] || 100 !== t[1] || 75 !== t[2]) throw Error("Scale To Pixel calculation self-check failed.")
}

function scaleLayerToPixels(e, t, a, i) {
    var $ = e.property("ADBE Transform Group"),
        l = $ && $.property("ADBE Scale");
    if (e.sourceRectAtTime && l) {
        var r = e.sourceRectAtTime(t, !1);
        if (!(r.width <= 0) && !(r.height <= 0)) {
            var o = l.valueAtTime(t, !1),
                c = calculatePixelScale(r.width, r.height, a, i, o);
            l.numKeys > 0 ? l.setValueAtTime(t, c) : l.setValue(c)
        }
    }
}

function scalelayers(e, t) {
    if (!(isNaN(e) || isNaN(t)) && !(e < 0) && !(t < 0) && (0 !== e || 0 !== t)) {
        var a = app.project.activeItem,
            i = a.selectedLayers;
        app.beginUndoGroup("Scale Layers To Pixels");
        try {
            for (var $ = 0; $ < i.length; $++) scaleLayerToPixels(i[$], a.time, e, t)
        } finally {
            app.endUndoGroup()
        }
    }
}
verifyScaleToPixelCalculation(), showui();