Selenium WebDriver C# 使用 ChromeDriver 和 FirefoxDriver 的完整网站屏幕截图

当我使用 ChromeDriver 截取屏幕截图时，我会得到与我的视口大小相同的屏幕。
当我使用 FirefoxDriver 截取屏幕截图时，我得到了我想要的，即网站的全屏打印。

ChromeDriver 声明如下：

IWebDriver driver = new ChromeDriver();

FirefoxDriver 声明如下：

IWebDriver driver = new FirefoxDriver();

两个驱动程序执行相同的代码：

driver.Manage().Window.Maximize();
driver.Navigate().GoToUrl(url);//url is a string variable
ITakesScreenshot screenshotDriver = driver as ITakesScreenshot;
Screenshot screenshot = screenshotDriver.GetScreenshot();
screenshot.SaveAsFile("c:/test.png", ImageFormat.Png);

ChromeDriver 的 test.png 分辨率为 1920x1099，仅包含浏览器视口。
FirefoxDriver 的 test.png 分辨率为 1903x16559，包含整个页面。

我知道GetScreenshot()方法不会返回相同的分辨率大小，因为它在 IEDriver、FirefoxDriver、OperaDriver、ChromeDriver 中的实现略有不同。

我的问题是：

1. 为什么 ChromeDriver 和 FirefoxDriver 之间有如此大的差异.GetScreenshot()方法，即使它们使用相同的界面（ITakesScreenshot）？

2. 有没有办法让ChromeDriver的GetScreenshot()方法返回整个网页屏幕而不仅仅是视口？

我们无法使用ChromeDriver2获取整个页面的屏幕截图，我们需要手动实现。我修改了博客中可用的方法，该方法与ChromeDriver配合良好。

使用此方法如下：

private IWebDriver _driver = new ChromeDriver(CHROME_DRIVER_PATH);
screenshot.SaveAsFile(saveFileName, ImageFormat.Jpeg);

public Bitmap GetEntereScreenshot()
    {

        Bitmap stitchedImage = null;
        try
        {
            long totalwidth1 = (long)((IJavaScriptExecutor)_driver).ExecuteScript("return document.body.offsetWidth");//documentElement.scrollWidth");

            long totalHeight1 = (long)((IJavaScriptExecutor)_driver).ExecuteScript("return  document.body.parentNode.scrollHeight");

            int totalWidth = (int)totalwidth1;
            int totalHeight = (int)totalHeight1;

            // Get the Size of the Viewport
            long viewportWidth1 = (long)((IJavaScriptExecutor)_driver).ExecuteScript("return document.body.clientWidth");//documentElement.scrollWidth");
            long viewportHeight1 = (long)((IJavaScriptExecutor)_driver).ExecuteScript("return window.innerHeight");//documentElement.scrollWidth");

            int viewportWidth = (int)viewportWidth1;
            int viewportHeight = (int)viewportHeight1;


        // Split the Screen in multiple Rectangles
        List<Rectangle> rectangles = new List<Rectangle>();
        // Loop until the Total Height is reached
        for (int i = 0; i < totalHeight; i += viewportHeight)
        {
            int newHeight = viewportHeight;
            // Fix if the Height of the Element is too big
            if (i + viewportHeight > totalHeight)
            {
                newHeight = totalHeight - i;
            }
            // Loop until the Total Width is reached
            for (int ii = 0; ii < totalWidth; ii += viewportWidth)
            {
                int newWidth = viewportWidth;
                // Fix if the Width of the Element is too big
                if (ii + viewportWidth > totalWidth)
                {
                    newWidth = totalWidth - ii;
                }

                // Create and add the Rectangle
                Rectangle currRect = new Rectangle(ii, i, newWidth, newHeight);
                rectangles.Add(currRect);
            }
        }

        // Build the Image
        stitchedImage = new Bitmap(totalWidth, totalHeight);
        // Get all Screenshots and stitch them together
        Rectangle previous = Rectangle.Empty;
        foreach (var rectangle in rectangles)
        {
            // Calculate the Scrolling (if needed)
            if (previous != Rectangle.Empty)
            {
                int xDiff = rectangle.Right - previous.Right;
                int yDiff = rectangle.Bottom - previous.Bottom;
                // Scroll
                //selenium.RunScript(String.Format("window.scrollBy({0}, {1})", xDiff, yDiff));
                ((IJavaScriptExecutor)_driver).ExecuteScript(String.Format("window.scrollBy({0}, {1})", xDiff, yDiff));
                System.Threading.Thread.Sleep(200);
            }

            // Take Screenshot
            var screenshot = ((ITakesScreenshot)_driver).GetScreenshot();

            // Build an Image out of the Screenshot
            Image screenshotImage;
            using (MemoryStream memStream = new MemoryStream(screenshot.AsByteArray))
            {
                screenshotImage = Image.FromStream(memStream);
            }

            // Calculate the Source Rectangle
            Rectangle sourceRectangle = new Rectangle(viewportWidth - rectangle.Width, viewportHeight - rectangle.Height, rectangle.Width, rectangle.Height);

            // Copy the Image
            using (Graphics g = Graphics.FromImage(stitchedImage))
            {
                g.DrawImage(screenshotImage, rectangle, sourceRectangle, GraphicsUnit.Pixel);
            }

            // Set the Previous Rectangle
            previous = rectangle;
        }
        }
        catch (Exception ex)
        {
            // handle
        }
        return stitchedImage;
    }