无头Chrome屏幕截图的最大高度为16,384px？

Question

无论我尝试什么，无头Chrome 60（和59）的整页屏幕截图的最大高度为16,348px。

这不是内存问题。没有段错误，例如，没有FATAL:memory_linux.cc(35) Out of memory.消息。没有。捕获屏幕截图是“成功的”。更改屏幕截图格式 - PNG或JPEG - 没有任何影响。

屏幕截图宽度可能会有所不同，但保存的屏幕截图的高度始终限制为16,348px。例，

1600x16384,1200x16384,2400x16384等

我用这个最小的代码（full source）进行了升级版的截图：

const upscale = 2;

const viewportWidth = 1200;
const viewportHeight = 800;

....

// Set up viewport resolution, etc.
const deviceMetrics = {
    width: viewportWidth,
    height: viewportHeight,
    deviceScaleFactor: 0,
    mobile: false,
    fitWindow: false,
    scale: 1    // Relative to the upscale
};
await Emulation.setDeviceMetricsOverride(deviceMetrics);
await Emulation.setVisibleSize({width: viewportWidth, height: viewportHeight});
await Emulation.setPageScaleFactor({pageScaleFactor: upscale});

// Navigate to target page
await Page.navigate({url});

const {root: {nodeId: documentNodeId}} = await DOM.getDocument();
const {nodeId: bodyNodeId} = await DOM.querySelector({
    selector: 'body',
    nodeId: documentNodeId,
});
const {model: {height}} = await DOM.getBoxModel({nodeId: bodyNodeId});

// Upscale the dimensions for full page
await Emulation.setVisibleSize({width: Math.round(viewportWidth * upscale), height: Math.round(height * upscale)});

// This forceViewport call ensures that content outside the viewport is
// rendered, otherwise it shows up as grey. Possibly a bug?
await Emulation.forceViewport({x: 0, y: 0, scale: upscale});

const screenshot = await Page.captureScreenshot({format});
const buffer = new Buffer(screenshot.data, 'base64');

file.writeFile(outFile, buffer, 'base64', function (err) {
    if (err) {
        console.error('Exception while saving screenshot:', err);
    } else {
        console.log('Screenshot saved');
    }
    client.close();
});

我也找不到任何有用的Chrome switches。这是Chrome的硬编码限制吗？ 16384是一个可疑数字（2 ^ 14 = 16,384）。如何增加这个高度？