How to take Retina Screenshots with Xvfb and Selenium
If you just want to take some screenhosts you can use google chrome headless tool. For example getting a retina screenshot is as easy as
$ google-chrome --headless --hide-scrollbars --disable-gpu \ --screenshot --force-device-scale-factor=2 \ --window-size=750,1334 https://www.kicktipp.de/
I'm facing the same problem and still stuck but the following may be useful. It allowed me to rule out either xvfb or chrome by attaching a VNC connection to the xvfb framebuffer.
#!/bin/bashexport GEOMETRY="$SCREEN_WIDTH""x""$SCREEN_HEIGHT""x""$SCREEN_DEPTH"function shutdown { kill -s SIGTERM $NODE_PID wait $NODE_PID}sudo -E -i -u seluser \ DISPLAY=$DISPLAY \ xvfb-run --server-args="$DISPLAY -screen 0 $GEOMETRY -dpi 300 -ac +extension RANDR" \ java -jar /opt/selenium/selenium-server-standalone.jar &NODE_PID=$!trap shutdown SIGTERM SIGINTfor i in $(seq 1 10)do xdpyinfo -display $DISPLAY >/dev/null 2>&1 if [ $? -eq 0 ]; then break fi echo Waiting xvfb... sleep 0.5donefluxbox -display $DISPLAY &x11vnc -forever -usepw -shared -rfbport 5900 -display $DISPLAY &wait $NODE_PIDAfter VNC'ing in, google-chrome GUI can be loaded from the terminal. Navigation to web pages confirm that Chrome is rendering the pages with the correct DPI. Screenshot http://i.stack.imgur.com/iEjo0.jpg
I would really like to get this working too so please reach out if you have any new developments. I used https://registry.hub.docker.com/u/selenium/standalone-chrome-debug/ BTW.
I switched to Firefox and it worked for me with the following code. But at the moment it doesn't as selenium is not working fine with my Firefox Version 47, see https://github.com/SeleniumHQ/selenium/issues/2257 So I can't test this code right now, but last time I was able to get retina screenshots with it:
package de.kicktipp.screenshots.stackoverflow;import java.awt.Image;import java.awt.image.BufferedImage;import java.io.File;import java.io.IOException;import java.util.ArrayList;import javax.imageio.ImageIO;import org.openqa.selenium.Dimension;import org.openqa.selenium.JavascriptExecutor;import org.openqa.selenium.WebDriver;import org.openqa.selenium.firefox.FirefoxBinary;import org.openqa.selenium.firefox.FirefoxDriver;import org.openqa.selenium.firefox.FirefoxProfile;public class ScreenshotMaker{ private PhoneList phoneList = new PhoneList(); private static final String HOST = "https://m.kicktipp.de"; private static final String PATH = "/"; private File resultDirectory; private int filenumber = 0; public static void main ( String[] args ) throws Exception { ScreenshotMaker screenshotMaker = new ScreenshotMaker(); screenshotMaker.run(); } public WebDriver getDriver ( Phone phone, Display display ) { FirefoxProfile profile = new FirefoxProfile(); // profile.setPreference("layout.css.devPixelsPerPx", "2.0"); // Ansonsten erscheint ein hässliches Popup welches Reader Funktion // anbietet profile.setPreference("reader.parse-on-load.enabled", false); profile.setPreference("xpinstall.signatures.required", false); FirefoxBinary firefoxBinary = new FirefoxBinary(); firefoxBinary.setEnvironmentProperty("DISPLAY", display.getDisplayNumberString()); FirefoxDriver firefoxDriver = new FirefoxDriver(firefoxBinary, profile); firefoxDriver.manage().window().setSize(new Dimension(phone.getWidth(), display.getHeight())); return firefoxDriver; } private void run ( ) throws Exception { mkdir(); for (Phone phone : phoneList) { WebDriver driver = null; Display display = null; try { display = new Display(phone.getDpiFaktor()); driver = getDriver(phone, display); System.out.println(phone.getName()); filenumber = 0; System.out.println(""); System.out.println("Generating Screenshots for " + phone.getName()); System.out.println("-----------------------------------------------------------------------------"); driver.get(HOST + "/"); shot(display, driver, PATH, phone); } finally { if (driver != null) { driver.quit(); } if (display != null) { display.shutdown(); } } } System.out.println(""); System.out.println("-----------------------------------------------------------------------------"); System.out.println("Finished."); } private void mkdir ( ) throws IOException { File targetDir = targetDir(); resultDirectory = new File(targetDir, "results"); resultDirectory.mkdir(); System.out.println("Writing screenshots to " + resultDirectory.getCanonicalPath()); } public File targetDir ( ) { String relPath = getClass().getProtectionDomain().getCodeSource().getLocation().getFile(); File targetDir = new File(relPath + "../.."); if (!targetDir.exists()) { targetDir.mkdir(); } return targetDir; } private void shot ( Display display, WebDriver driver, String path, Phone phoneSpec ) throws Exception { String url = getUrl(path); driver.get(url); scrollToRemoveScrollbars(driver); // Selenium screenshot doesn't work, we are dumping the framebuffer // directly File srcFile = display.captureScreenshot(); moveFile(srcFile, phoneSpec); } private void scrollToRemoveScrollbars ( WebDriver driver ) throws Exception { JavascriptExecutor js = (JavascriptExecutor) driver; js.executeScript("window.scrollTo(0,20);"); js.executeScript("window.scrollTo(0,0);"); Thread.sleep(800); } private String getUrl ( String path ) { StringBuffer url = new StringBuffer(HOST); url.append(path); return url.toString(); } private void moveFile ( File srcFile, Phone phone ) throws Exception { String filename = phone.getFilename(filenumber); File file = new File(resultDirectory, filename); if (file.exists()) { file.delete(); } crop(srcFile, file, phone); System.out.println(filename); } private void crop ( File srcFile, File targetFile, Phone phone ) throws Exception { int width = phone.getPixelWidth(); int height = phone.getPixelHeight(); int yStart = 71 * phone.getDpiFaktor(); Image orig = ImageIO.read(srcFile); BufferedImage bi = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB); bi.getGraphics().drawImage(orig, 0, 0, width, height, 0, yStart, width, height + yStart, null); ImageIO.write(bi, "png", targetFile); }}class PhoneList extends ArrayList<Phone>{ private static final Phone IPHONE_4 = new Phone(320, 460, "iphone4", 2); private static final Phone IPHONE_5 = new Phone(320, 548, "iphone5", 2); private static final Phone IPHONE_6 = new Phone(375, 667, "iphone6", 2); private static final Phone IPAD = new Phone(1024, 748, "ipad", 2); private static final Phone IPHONE_6_PLUS = new Phone(414, 736, "iphone6plus", 3); private static final Phone AMAZON = new Phone(480, 800, "amazon", 1); public PhoneList () { add(AMAZON); add(IPHONE_4); add(IPHONE_5); add(IPHONE_6); add(IPAD); add(IPHONE_6_PLUS); }}class Phone{ private int width = 0; private int height = 0; private String name = ""; private int dpiFaktor = 2; public Phone ( int width, int height, String name, int dpiFaktor ) { this.width = width; this.height = height; this.name = name; this.dpiFaktor = dpiFaktor; } public int getWidth ( ) { return width; } public int getHeight ( ) { return height; } public int getPixelWidth ( ) { return width * dpiFaktor; } public int getPixelHeight ( ) { return height * dpiFaktor; } public int getDpiFaktor ( ) { return dpiFaktor; } public String getName ( ) { return name; } public Dimension getDimension ( ) { return new Dimension(width, height); } public String getFilename ( int number ) { String dimension = getPixelWidth() + "x" + getPixelHeight(); return name + "-" + dimension + "-" + number + ".png"; }}class Display{ private static final int HEIGHT = 5000; private static final int WIDTH = 5000; private static String XVFB = "/usr/bin/Xvfb"; private static String DISPLAY_NUMBER_STRING = ":99"; private static String SCREEN_SIZE = " -screen 0 " + WIDTH + "x" + HEIGHT + "x24"; private static String XVFB_COMMAND = XVFB + " " + DISPLAY_NUMBER_STRING + SCREEN_SIZE + " -dpi "; private static int baseDpi = 100; private Process p; public Display ( int dpiFaktor ) throws IOException, InterruptedException { checkExecutable(); int dpi = baseDpi * dpiFaktor; String cmd = XVFB_COMMAND + dpi; p = Runtime.getRuntime().exec(cmd); Thread.sleep(1000); try { int exitValue = p.exitValue(); String msgTemplate = "ERROR: Exit Value: %s. Display konnte nicht gestartet werden. Läuft ein Display noch auf %s ?"; String msg = String.format(msgTemplate, exitValue, DISPLAY_NUMBER_STRING); throw new IllegalStateException(msg); } catch (IllegalThreadStateException e) { // Das ist gut, der Prozess ist noch nicht beendet. System.out.println("Switched on display at " + dpi + "dpi with command " + cmd); return; } } private void checkExecutable ( ) { File file = new File(XVFB); if (!file.canExecute()) { System.err.println("Xvfb is not installed at " + XVFB); System.err.println("Install Xvfb by runing"); System.err.println("apt-get install xvfb"); } } public File captureScreenshot ( ) throws IOException, InterruptedException { File tempFile = File.createTempFile("screenshots", ".png"); String absolutePath = tempFile.getAbsolutePath(); String cmd = "import -window root " + absolutePath; String[] env = new String[] { "DISPLAY=" + DISPLAY_NUMBER_STRING }; Process exec = Runtime.getRuntime().exec(cmd, env); exec.waitFor(); return tempFile; } public void shutdown ( ) throws IOException, InterruptedException { p.destroy(); try { Thread.sleep(1000); int exitValue = p.exitValue(); System.out.println("Display was switched off. ExitValue: " + exitValue); } catch (IllegalThreadStateException e) { // Das ist nicht gut, der Prozess sollte beendet sein. // Kill it: p = Runtime.getRuntime().exec("pkill Xvfb"); } } public String getDisplayNumberString ( ) { return DISPLAY_NUMBER_STRING; } public int getHeight ( ) { return HEIGHT; }}And this is my pom:
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>de.kicktipp</groupId> <artifactId>screenshots</artifactId> <version>0.0.1-SNAPSHOT</version> <name>screenshots</name> <properties> <jdk.version>1.7</jdk.version> <maven.version>3.0</maven.version> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <selenium-java.version>2.53.1</selenium-java.version> </properties> <build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-compiler-plugin</artifactId> <configuration> <source>${jdk.version}</source> <target>${jdk.version}</target> </configuration> </plugin> </plugins> </build> <dependencies> <dependency> <groupId>org.seleniumhq.selenium</groupId> <artifactId>selenium-java</artifactId> <version>${selenium-java.version}</version> </dependency> </dependencies></project>