Smart_Layer_Export.jsx

#target photoshop
app.bringToFront();

if (!app.documents.length) {
    alert("请先打开一个 PSD 文件。");
    throw new Error("No document open");
}

var doc = app.activeDocument;

// =====================================================
// 判断是否存在选区
// 有选区：按选区范围导出
// 无选区：按整个画布导出
// =====================================================
function getExportBounds() {
    try {
        var b = doc.selection.bounds;
        return {
            hasSelection: true,
            left: b[0].as("px"),
            top: b[1].as("px"),
            right: b[2].as("px"),
            bottom: b[3].as("px")
        };
    } catch (e) {
        return {
            hasSelection: false,
            left: 0,
            top: 0,
            right: doc.width.as("px"),
            bottom: doc.height.as("px")
        };
    }
}

var bounds = getExportBounds();

var exportWidth = bounds.right - bounds.left;
var exportHeight = bounds.bottom - bounds.top;

if (exportWidth <= 0 || exportHeight <= 0) {
    alert("导出尺寸无效，请检查选区或画布。");
    throw new Error("Invalid export bounds");
}

var modeText = bounds.hasSelection ? "选区范围导出 / Selection Bounds Export" : "画布范围导出 / Canvas Export";
var isSelectionMode = bounds.hasSelection;

// =====================================================
// 选择导出文件夹
// =====================================================
var outFolder = Folder.selectDialog(
    "选择 PNG 导出文件夹\n\n" +
    "导出模式：" + modeText + "\n" +
    "导出尺寸：" + exportWidth + " × " + exportHeight + " px"
);

if (!outFolder) {
    throw new Error("No output folder selected");
}

// =====================================================
// 获取当前选中的图层 ID
// =====================================================
function getSelectedLayerIDs() {
    var selected = [];

    var ref = new ActionReference();
    ref.putProperty(charIDToTypeID("Prpr"), stringIDToTypeID("targetLayers"));
    ref.putEnumerated(charIDToTypeID("Dcmn"), charIDToTypeID("Ordn"), charIDToTypeID("Trgt"));

    try {
        var desc = executeActionGet(ref);

        if (desc.hasKey(stringIDToTypeID("targetLayers"))) {
            var list = desc.getList(stringIDToTypeID("targetLayers"));

            for (var i = 0; i < list.count; i++) {
                var layerIndex = list.getReference(i).getIndex();

                var ref2 = new ActionReference();
                ref2.putIndex(charIDToTypeID("Lyr "), layerIndex);

                var desc2 = executeActionGet(ref2);
                selected.push(desc2.getInteger(stringIDToTypeID("layerID")));
            }
        }
    } catch (e) {
        selected.push(doc.activeLayer.id);
    }

    return selected;
}

// =====================================================
// 按 ID 查找图层 / 图层组
// =====================================================
function findLayerByID(container, id) {
    for (var i = 0; i < container.layers.length; i++) {
        var layer = container.layers[i];

        if (layer.id === id) {
            return layer;
        }

        if (layer.typename === "LayerSet") {
            var found = findLayerByID(layer, id);
            if (found) return found;
        }
    }

    return null;
}

// =====================================================
// 可见性记录 / 恢复
// =====================================================
function saveVisibility(container, map) {
    for (var i = 0; i < container.layers.length; i++) {
        var layer = container.layers[i];

        map[layer.id] = layer.visible;

        if (layer.typename === "LayerSet") {
            saveVisibility(layer, map);
        }
    }
}

function restoreVisibility(container, map) {
    for (var i = 0; i < container.layers.length; i++) {
        var layer = container.layers[i];

        if (map.hasOwnProperty(layer.id)) {
            try {
                layer.visible = map[layer.id];
            } catch (e) {}
        }

        if (layer.typename === "LayerSet") {
            restoreVisibility(layer, map);
        }
    }
}

function hideAll(container) {
    for (var i = 0; i < container.layers.length; i++) {
        var layer = container.layers[i];

        try {
            layer.visible = false;
        } catch (e) {}

        if (layer.typename === "LayerSet") {
            hideAll(layer);
        }
    }
}

// =====================================================
// 显示目标图层及其父级
// =====================================================
function showLayerAndParents(layer) {
    var current = layer;

    while (current && current.typename !== "Document") {
        try {
            current.visible = true;
        } catch (e) {}

        current = current.parent;
    }
}

// 如果目标是图层组，恢复组内原本可见的子图层状态
function restoreGroupChildrenVisibility(layerSet, visibilityMap) {
    for (var i = 0; i < layerSet.layers.length; i++) {
        var layer = layerSet.layers[i];

        if (visibilityMap.hasOwnProperty(layer.id)) {
            try {
                layer.visible = visibilityMap[layer.id];
            } catch (e) {}
        }

        if (layer.typename === "LayerSet") {
            restoreGroupChildrenVisibility(layer, visibilityMap);
        }
    }
}

// =====================================================
// 文件名清理
// =====================================================
function sanitizeFileName(name) {
    return name.replace(/[\\\/\:\*\?\"\<\>\|]/g, "_");
}

// =====================================================
// 防止重名覆盖：如果文件已存在，自动追加编号
// =====================================================
function getUniqueFile(folder, baseName, ext) {
    var file = new File(folder.fsName + "/" + baseName + ext);
    var count = 1;

    while (file.exists) {
        file = new File(folder.fsName + "/" + baseName + "_" + count + ext);
        count++;
    }

    return file;
}

// =====================================================
// 保存 PNG
// =====================================================
function savePNG(targetDoc, file) {
    app.activeDocument = targetDoc;

    var opts = new PNGSaveOptions();
    opts.compression = 9;
    opts.interlaced = false;

    targetDoc.saveAs(file, opts, true, Extension.LOWERCASE);
}

// =====================================================
// Selection Mode：有选区时使用临时文档裁切导出
// =====================================================
function exportBySelection(layer, fileName) {
    app.activeDocument = doc;

    var tempDoc = doc.duplicate();
    app.activeDocument = tempDoc;

    tempDoc.crop([
        UnitValue(bounds.left, "px"),
        UnitValue(bounds.top, "px"),
        UnitValue(bounds.right, "px"),
        UnitValue(bounds.bottom, "px")
    ]);

    var outFile = getUniqueFile(outFolder, fileName, ".png");

    savePNG(tempDoc, outFile);

    tempDoc.close(SaveOptions.DONOTSAVECHANGES);
}

// =====================================================
// Canvas Mode：无选区时直接按当前画布快速导出
// 不复制文档，不裁切，所以速度更快
// =====================================================
function exportByCanvas(layer, fileName) {
    app.activeDocument = doc;

    var outFile = getUniqueFile(outFolder, fileName, ".png");

    savePNG(doc, outFile);
}

// =====================================================
// 主逻辑
// =====================================================
var selectedIDs = getSelectedLayerIDs();

if (!selectedIDs.length) {
    alert("请先选中至少一个图层或图层组。");
    throw new Error("No layers selected");
}

var visibilityMap = {};
saveVisibility(doc, visibilityMap);

var exportedCount = 0;

try {
    for (var i = 0; i < selectedIDs.length; i++) {
        app.activeDocument = doc;

        var layer = findLayerByID(doc, selectedIDs[i]);

        if (!layer) continue;

        hideAll(doc);
        showLayerAndParents(layer);

        if (layer.typename === "LayerSet") {
            restoreGroupChildrenVisibility(layer, visibilityMap);
        }

        var fileName = sanitizeFileName(layer.name);

        if (isSelectionMode) {
            exportBySelection(layer, fileName);
        } else {
            exportByCanvas(layer, fileName);
        }

        exportedCount++;
    }

    app.activeDocument = doc;

    alert(
        "导出完成。\n\n" +
        "导出模式：" + modeText + "\n" +
        "导出数量：" + exportedCount + " 个 PNG\n" +
        "导出尺寸：" + exportWidth + " × " + exportHeight + " px"
    );

} catch (err) {
    alert("导出失败：" + err.message);
} finally {
    app.activeDocument = doc;
    restoreVisibility(doc, visibilityMap);
}