Selenium - 以相等的间隔滚动以捕获整个网页时生成的额外屏幕截图

Posted 2023-03-24

【中文标题】Selenium - 以相等的间隔滚动以捕获整个网页时生成的额外屏幕截图

【英文标题】：Selenium - Extra screenshots generated when scrolling in equivalent intervals to capture an entire web page

【发布时间】：2019-07-07 16:38:15

【问题描述】：

目标：使用 Java 和 JSExecutor for Selenium WebDriver 以相等的间隔滚动以截取整个页面。

问题：我在下面实现的方法有效，但是，我最终在结束时有 2-3 个额外的屏幕截图网页 - 我想避免这些多余的屏幕截图。

滚动方式如下：

public static void pageScrollable() throws InterruptedException, IOException 

    javascriptExecutor jse = (JavascriptExecutor) driver;

    //Find page height
    pageHeight = ((Number) jse.executeScript("return document.body.scrollHeight")).intValue();
    //Find current browser dimensions and isolate its height
    Dimension d = driver.manage().window().getSize();
    int browserSize = d.getHeight();

    int currentHeight = 0;      
    System.out.println("Current scroll at: " + currentHeight);
    System.out.println("Page height is: " + pageHeight + "\n");

    //Scrolling logic
    while(pageHeight>=currentHeight)   
        jse.executeScript("window.scrollBy(0,"+currentHeight+")", "");
        screenShot();
        currentHeight+=browserSize;
        System.out.println("Current scroll now at: " + currentHeight);
       

截图方法如下：

public static void screenShot() throws IOException, InterruptedException 
    File screenShot = ((TakesScreenshot)driver).getScreenshotAs(OutputType.FILE);
    FileUtils.copyFile(screenShot, new File("C:\\FilePath\\Screen " + count + ".png"));
    count++;
    System.out.println("Current screenshot count: " + count);

以下变量被定义为静态：

static int pageHeight = 0;
static int count = 0;
static WebDriver driver;

我知道目前没有使用 Selenium 捕获整个网页的屏幕的实现。任何帮助解决我的上述逻辑将不胜感激。

【参考方案1】：

您的滚动逻辑是附加图像的原因。 Window.scrollBy 方法滚动多个像素而不是绝对位置。你需要滚动browserSize。

也许您应该使用

来标识视口大小而不是浏览器窗口大小

int browserSize = ((Number) jse.executeScript("return window.innerHeight")).intValue();

我添加了一个完整的示例，如何使用 Chrome 获取单页屏幕截图：

package demo;

import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.IOException;
import java.util.LinkedList;
import java.util.List;
import javax.imageio.ImageIO;
import org.openqa.selenium.JavascriptExecutor;
import org.openqa.selenium.OutputType;
import org.openqa.selenium.TakesScreenshot;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebDriverException;
import org.openqa.selenium.chrome.ChromeDriver;

public class WebDriverDemo 
  static int pageHeight = 0;
  static int count = 0;
  static WebDriver driver;
  static List<BufferedImage> images = new LinkedList<>();

  public static void main(String[] args) 
    driver = new ChromeDriver();

    driver.get("http://automationpractice.com/");
    try 
      pageScrollable();

     catch (WebDriverException | InterruptedException | IOException e) 
      e.printStackTrace();
    

    driver.quit();
  

  public static void pageScrollable() throws InterruptedException, IOException 

    JavascriptExecutor jse = (JavascriptExecutor) driver;

    // Find page height
    pageHeight = ((Number) jse.executeScript("return document.body.scrollHeight")).intValue();
    // Find current browser dimensions and isolate its height
    int browserSize = ((Number) jse.executeScript("return window.innerHeight")).intValue();
    System.out.println("Page height is: " + pageHeight + "\n");
    System.out.println("Browser height is: " + browserSize + "\n");

    int currentHeight = 0;
    System.out.println("Current scroll at: " + currentHeight);
    System.out.println("Page height is: " + pageHeight + "\n");

    // Scrolling logic
    while (pageHeight >= currentHeight) 
      screenShot();
      currentHeight += browserSize;
      jse.executeScript("window.scrollBy(0," + browserSize + ")", "");
      System.out.println("Current scroll now at: " + currentHeight);
    

    BufferedImage result = null;
    Graphics2D g2d = null;
    int heightCurr = 0;
    System.out.println("Image count is " + images.size());
    for (int i = 0; i < images.size(); i++) 
      BufferedImage img = images.get(i);
      int imageHeight = 0;
      if (result == null) 
        System.out.println("Image height is " + img.getHeight()); // differs from browserSize
        imageHeight = pageHeight + images.size() * (img.getHeight() - browserSize);
        result = new BufferedImage(img.getWidth(), imageHeight, img.getType());
        g2d = result.createGraphics();
      
      if (i == images.size() - 1) 
        g2d.drawImage(img, 0, imageHeight - img.getHeight(), null);
       else 
        g2d.drawImage(img, 0, heightCurr, null);
        heightCurr += img.getHeight();
      
    
    g2d.dispose();
    ImageIO.write(result, "png", new File("screenshot.png"));
  

  public static void screenShot() throws IOException, InterruptedException 
    byte[] scr = ((TakesScreenshot) driver).getScreenshotAs(OutputType.BYTES);
    BufferedImage img = ImageIO.read(new ByteArrayInputStream(scr));
    images.add(img);
  

不幸的是，由于其Window.scrollBy 实现中的故障，它无法通过 FireFox 提供正确的结果。