Screenshot issue in selenium webdriver with scroll and result in one image file

Question

I have a screen shot issue. When I am capturing a screen, it takes only the Visible screen. I want to capture the entire page. Here below is my code.

I found several solutions but that does not suit me. I am looking for a solution where the final screenshot is a single merged image.

I tried ashot library:

<dependency>
    <groupId>ru.yandex.qatools.ashot</groupId>
    <artifactId>ashot</artifactId>
    <version>1.5.2</version>
</dependency>

And use the code snippet as follows:

DesiredCapabilities capabilities = DesiredCapabilities.chrome();
WebDriver driver = new ChromeDriver(capabilities);
driver.get("https://stackoverflow.com/questions/10245641/refreshing-web-page-by-webdriver-when-waiting-for-specific-condition");
String screenName = "poc";
String USER_DIR = "user.dir";
String DOWNLOADED_FILES_FOLDER = "downloadFiles";
Screenshot screenshot2 = new AShot().shootingStrategy(ShootingStrategies.viewportPasting(1000)).takeScreenshot(driver);
ImageIO.write(screenshot2.getImage(), "PNG", new File(System.getProperty(USER_DIR) + File.separator + DOWNLOADED_FILES_FOLDER + File.separator + screenName + ".jpg"));

I tried scroll by javascript + tack any screenshot:

    DesiredCapabilities capabilities = DesiredCapabilities.chrome();
        WebDriver driver = new ChromeDriver(capabilities);
        driver.get("http://www.w3schools.com/");
        driver.manage().timeouts().pageLoadTimeout(30, TimeUnit.SECONDS);
        JavascriptExecutor jexec = (JavascriptExecutor) driver;
        boolean isScrollBarPresent = (boolean) jexec.executeScript("return document.documentElement.scrollHeight>document.documentElement.clientHeight");
        long scrollHeight = (long) jexec.executeScript("return document.documentElement.scrollHeight");
        long clientHeight = (long) jexec.executeScript("return document.documentElement.clientHeight");
        int fileIndex = 1;
        if (driver instanceof ChromeDriver) {
            if (isScrollBarPresent) {
                while (scrollHeight > 0) {
                    File srcFile = ((TakesScreenshot) driver).getScreenshotAs(OutputType.FILE);
                    org.apache.commons.io.FileUtils.copyFile(srcFile, new File(System.getProperty(USER_DIR) + File.separator + DOWNLOADED_FILES_FOLDER + File.separator + fileIndex + ".jpg"));
                    jexec.executeScript("window.scrollTo(0," + clientHeight * fileIndex++ + ")");
                    scrollHeight = scrollHeight - clientHeight;
                }
            } else {
                File srcFile = ((TakesScreenshot) driver).getScreenshotAs(OutputType.FILE);
                org.apache.commons.io.FileUtils.copyFile(srcFile, new File(System.getProperty(USER_DIR) + File.separator + DOWNLOADED_FILES_FOLDER + File.separator + fileIndex + ".jpg"));
            }
        } else {
            File srcFile = ((TakesScreenshot) driver).getScreenshotAs(OutputType.FILE);
            org.apache.commons.io.FileUtils.copyFile(srcFile, new File(System.getProperty(USER_DIR) + File.separator + DOWNLOADED_FILES_FOLDER + File.separator + fileIndex + ".jpg"));
        }
        // Combine all the .jpg file to single file

        driver.close();
        driver.quit();

This solution return a lot of picture and Combine all the image file to single file is not easy.

I tried MultiScreenShot library:

https://github.com/Pavan-and-Vikas-Utilities/MultiScreenShot

This solution return a lot of picture and Combine all the image file to single file is not easy.

Sample (produced by FastStone Capture) of result with this url (I looking for this result): Refreshing web page by WebDriver when waiting for specific condition