#target photoshop

/*
    Uniformly scale the active Photoshop layer.
    Input range: 0.1 to 1.0
    Default: 0.5 (50%)
*/

(function () {
    function showMessage(text) {
        alert(text);
    }

    function hasSelectedLayer() {
        var propertyID = stringIDToTypeID("targetLayersIDs");
        var reference = new ActionReference();
        reference.putProperty(stringIDToTypeID("property"), propertyID);
        reference.putEnumerated(
            stringIDToTypeID("document"),
            stringIDToTypeID("ordinal"),
            stringIDToTypeID("targetEnum")
        );

        try {
            var descriptor = executeActionGet(reference);
            return descriptor.hasKey(propertyID) &&
                   descriptor.getList(propertyID).count > 0;
        } catch (error) {
            return false;
        }
    }

    if (app.documents.length === 0) {
        showMessage("打开一个文档以使用此脚本。");
        return;
    }

    if (!hasSelectedLayer()) {
        showMessage("请先选择一个需要缩放的图层。");
        return;
    }

    var dialog = new Window("dialog", "缩放选定图层");
    dialog.orientation = "column";
    dialog.alignChildren = "fill";

    var inputGroup = dialog.add("group");
    inputGroup.orientation = "row";
    inputGroup.add("statictext", undefined, "缩放比例(0.1-1):");
    var scaleInput = inputGroup.add("edittext", undefined, "0.5");
    scaleInput.characters = 8;
    scaleInput.active = true;

    var buttonGroup = dialog.add("group");
    buttonGroup.alignment = "right";
    var cancelButton = buttonGroup.add("button", undefined, "Cancel", { name: "cancel" });
    var okButton = buttonGroup.add("button", undefined, "OK", { name: "ok" });

    var scaleValue = null;

    okButton.onClick = function () {
        var value = parseFloat(scaleInput.text.replace(",", "."));

        if (isNaN(value) || value < 0.1 || value > 1) {
            showMessage("Enter a number from 0.1 to 1.");
            scaleInput.active = true;
            return;
        }

        scaleValue = value;
        dialog.close(1);
    };

    cancelButton.onClick = function () {
        dialog.close(0);
    };

    if (dialog.show() !== 1 || scaleValue === null) {
        return;
    }

    try {
        var layer = app.activeDocument.activeLayer;
        var percent = scaleValue * 100;

        layer.resize(
            percent,
            percent,
            AnchorPosition.MIDDLECENTER
        );
    } catch (error) {
        showMessage("Scale failed:\n" + error.message);
    }
}());