使用 Selenium Webdriver TakesScreenshot 方法捕获 base64 图像。我可以减小图像尺寸吗？

Question

我正在使用 Selenium 的 TakesScreenshot 方法将 base64 字符串添加到我的 HTML 报告中。报告 (extentreports) 中生成的屏幕截图有点太大，部分被推到屏幕外。缩小它也会减小报告的文件大小。

我可以截取更小的 base64 屏幕截图吗？将其缩小约 20% 将是完美的……或者我是否必须先将图像创建为 File，然后将其缩小，然后转换为 base64。

 public static String CaptureScreen(WebDriver driver) {
    TakesScreenshot newScreen = (TakesScreenshot) driver;
    String scnShot = newScreen.getScreenshotAs(OutputType.BASE64);
    return "data:image/jpg;base64, " + scnShot ;
}

Answer 1

如果您想截取较小的屏幕截图文件。您应该降低图像质量或写入具有固定尺寸（高度 x 宽度）的文件。让我们检查一下我的解决方案，希望对您有所帮助：

图书馆：

<!-- SELENIUM LIBs and Image Process LIBs -->
    <dependency>
        <groupId>org.seleniumhq.selenium</groupId>
        <artifactId>selenium-firefox-driver</artifactId>
        <version>2.41.0</version>
    </dependency>
    <dependency>
        <groupId>org.seleniumhq.selenium</groupId>
        <artifactId>selenium-java</artifactId>
        <version>2.41.0</version>
    </dependency>
    <dependency>
        <groupId>xml-apis</groupId>
        <artifactId>xml-apis</artifactId>
        <version>1.4.01</version>
    </dependency>
    <dependency>
        <groupId>com.sun.media</groupId>
        <artifactId>jai_codec</artifactId>
        <version>1.1.3</version>
    </dependency>
    <dependency>
        <groupId>javax.media</groupId>
        <artifactId>jai_core</artifactId>
        <version>1.1.3</version>
    </dependency>

解决方法：首先使用reduce image quality，我定义

最大图像大小为：例如：1048576

截屏到文件（你选择是不是base64由你决定）

</p>

<p>import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.image.BufferedImage;
import java.awt.image.ColorModel;
import java.awt.image.ImageObserver;
import java.awt.image.RenderedImage;
import java.awt.image.WritableRaster;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.util.Hashtable;
import java.util.Iterator;
import javax.imageio.IIOImage;
import javax.imageio.ImageIO;
import javax.imageio.ImageWriteParam;
import javax.imageio.ImageWriter;
import javax.imageio.stream.FileImageOutputStream;</p>

<p>/**</p>

<ul>
<li><p>@author daviddoan
*
*/
public class ScreenShotUtils implements ImageObserver {</p>

<p>private static final Color BKGROUND_COLOR = Color.WHITE;
private boolean imageLoaded = false;</p>

<p>private static BufferedImage matrixTransparentPixels(BufferedImage originalBufferedImage, Color fillColor) {
int w = originalBufferedImage.getWidth();
int h = originalBufferedImage.getHeight();
BufferedImage newGeneratedBufferedImage;
if (originalBufferedImage.getType() == BufferedImage.TYPE_4BYTE_ABGR) {
  newGeneratedBufferedImage = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
} else {
  newGeneratedBufferedImage = new BufferedImage(w, h, originalBufferedImage.getType());
}
// clone the original image
Graphics2D graphics2D = null;
try {
  graphics2D = newGeneratedBufferedImage.createGraphics();
  graphics2D.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BICUBIC);
  graphics2D.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
  graphics2D.setRenderingHint(RenderingHints.KEY_ALPHA_INTERPOLATION, RenderingHints.VALUE_ALPHA_INTERPOLATION_QUALITY);
  final boolean isDrawingSuccess = graphics2D.drawImage(originalBufferedImage, 0, 0, w, h, fillColor, null);
  if (!isDrawingSuccess) {
  while (!imageLoaded) {
    System.err.println("DRAWING IMAGE, PLEASE WAITING...");
    Thread.sleep(10000);
  }
  }
} finally {
  if (graphics2D != null) {
    graphics2D.dispose();
  }
}</p>

<p>return newGeneratedBufferedImage;
}</p>

<p>public static void reduceScreenShotQuality(File screenshotSource, String location, String fileName, String fileExtension) throws Exception {</p>

<p>int sizeThreshold = 1048576;
float quality = 1.0f;
long fileSize = screenshotSource.length();</p>

<p>if (fileSize <= sizeThreshold) {
  // Image file size is small, no need reduced any more.;
  writeImageToLocation(screenshotSource, location, fileName, "jpeg");
  return;
}</p>

<p>// Need to reduce 'cos over sizeThreshold</p>

<p>ImageWriter writer = createImageWriter();</p>

<p>ImageWriteParam iwp = writer.getDefaultWriteParam();</p>

<p>iwp.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);</p>

<p>InputStream inputStream = new FileInputStream(screenshotSource);</p>

<p>FileImageOutputStream output = getOutputStream(location, fileName, fileExtension);</p>

<p>BufferedImage originalImage = ImageIO.read(inputStream);
BufferedImage newBufferedImage;</p>

<p>newBufferedImage = matrixTransparentPixels(originalImage, BKGROUND_COLOR);</p>

<p>float percent = 0.1f; // 10% of 1</p>

<p>while (fileSize > sizeThreshold) {
  if (percent >= quality) {
    percent = percent * 0.1f;
  }</p>

<p>quality -= percent;</p>

<p>iwp.setCompressionQuality(quality);</p>

<p>writeImage(writer, newBufferedImage, output, iwp);</p>

<p>File fileOut2 = new File(location + fileName + "." + fileExtension);
  long newFileSize = fileOut2.length();
  if (newFileSize == fileSize) {
    // cannot reduce more
    break;
  } else {
    fileSize = newFileSize;
  }
}
// Flush all stream
inputStream.close();
originalImage.flush();
newBufferedImage.flush();
writer.dispose();
}</p>

<p>private static void writeImage(ImageWriter writer, BufferedImage bufferedImage, FileImageOutputStream output, ImageWriteParam iwp) {
try {
  IIOImage image = new IIOImage(bufferedImage, null, null);
  writer.setOutput(output);</p>

<p>if (iwp != null) {
    writer.write(null, image, iwp);
  } else {
    writer.write(image);
  }
  output.close();
} catch (IOException e) {
  System.err.println("writeImage: IOException- " + e.getMessage());
} finally {
  System.err.println("End writeImage");
}</p>

<p>}</p>

<p>private static FileImageOutputStream getOutputStream(String location, String fileName, String fileExtension) throws FileNotFoundException, IOException {
File fileOut = new File(location + fileName + "." + fileExtension);
if (fileOut.exists()) {
  fileOut.delete();
}
FileImageOutputStream output = new FileImageOutputStream(fileOut);</p>

<p>return output;
}</p>

<p>private static ImageWriter createImageWriter() {
Iterator iter = ImageIO.getImageWritersByFormatName("jpeg");
ImageWriter writer = (ImageWriter) iter.next();
return writer;
}</p>

<p>private static void writeImageToLocation(File filePng, String location, String fileName, String extension) throws IOException {
ImageWriter writer = createImageWriter();</p>

<p>ImageWriteParam iwp = writer.getDefaultWriteParam();</p>

<p>SeekableStream seekableStream = new FileSeekableStream(filePng);
PNGDecodeParam pngParams = new PNGDecodeParam();
ImageDecoder dec = ImageCodec.createImageDecoder("png", seekableStream, pngParams);
RenderedImage pngImage = dec.decodeAsRenderedImage();</p>

<p>BufferedImage newImage = new BufferedImage(pngImage.getWidth(), pngImage.getHeight(), BufferedImage.TYPE_INT_RGB);</p>

<p>newImage.createGraphics().drawImage(renderedImageToBufferedImage(pngImage), 0, 0, Color.BLACK, null);</p>

<p>FileImageOutputStream output = getOutputStream(location, fileName, extension);
writeImage(writer, newImage, output, iwp);</p>

<p>newImage.flush();
seekableStream.close();
writer.dispose();
}</p>

<p>private static BufferedImage renderedImageToBufferedImage(RenderedImage img) {
if (img instanceof BufferedImage) {
  return (BufferedImage) img;
}
ColorModel cm = img.getColorModel();
int width = img.getWidth();
int height = img.getHeight();
WritableRaster raster = cm.createCompatibleWritableRaster(width, height);
boolean isAlphaPremultiplied = cm.isAlphaPremultiplied();
Hashtable properties = new Hashtable();
String[] keys = img.getPropertyNames();
if (keys != null) {
  for (String key : keys) {
    properties.put(key, img.getProperty(key));
  }
}
BufferedImage result = new BufferedImage(cm, raster, isAlphaPremultiplied, properties);
img.copyData(raster);
return result;
}
}
@Override
public boolean imageUpdate(Image img, int infoflags, int x, int y, int width, int height) {
    if (infoflags != ALLBITS) {
        // Image has not finished loading!
        // Return true to tell the image loading thread to keep drawing until image fully loads.
        return true;
    } else {
        imageLoaded = true;
        return false;
    }
}
</pre>


解决方案：写成缩略图（高 x 宽）

</p>

<p>import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.RenderingHints;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.awt.image.ImageObserver;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;</p>

<p>import javax.imageio.ImageIO;
import javax.media.jai.JAI;
import javax.media.jai.RenderedOp;</p>

<p>import org.apache.log4j.Logger;</p>

<p>import com.sun.media.jai.codec.SeekableStream;</p>

<p>/**</p>

<ul>
<li><ul>
<li>@author daviddoan
*
*/</li>
</ul></li>
</ul>

<p>public class ThumbnailUtils implements ImageObserver {</p>

<pre><code>private static final String CLASS_NAME = ThumbnailUtils.class.getSimpleName();

private final Color BKGROUND_COLOR = Color.WHITE;
private boolean imageLoaded = false;

public void writeThumbnail(String originalImagePath, int thumbWidth, int thumbHeight, String thumbImagePath)
        throws Exception {

    InputStream originalImageStream = new FileInputStream(originalImagePath);
    File fileOut = new File(thumbImagePath);
    if (fileOut.exists()) {
        fileOut.delete();
    }
    OutputStream thumbImageOutStream = new FileOutputStream(fileOut);
    writeThumbnail(originalImageStream, thumbWidth, thumbHeight, thumbImageOutStream);
    thumbImageOutStream.close();
    originalImageStream.close();
}

public void writeThumbnail(File file, int thumbWidth, int thumbHeight, String thumbImagePath) throws Exception {

    InputStream originalImageStream = new FileInputStream(file);
    File fileOut = new File(thumbImagePath);
    if (fileOut.exists()) {
        fileOut.delete();
    }
    OutputStream thumbImageOutStream = new FileOutputStream(fileOut);

    writeThumbnail(originalImageStream, thumbWidth, thumbHeight, thumbImageOutStream);

    thumbImageOutStream.close();
    originalImageStream.close();

}

private void writeThumbnail(InputStream originalImageStream, int thumbWidth, int thumbHeight,
        OutputStream thumbImageOutStream) throws Exception {

    ByteArrayOutputStream byteArrOutputStream = null;
    try {
        byteArrOutputStream = makeThumbnail(originalImageStream, thumbWidth, thumbHeight);
        byteArrOutputStream.writeTo(thumbImageOutStream);
        byteArrOutputStream.flush();
    } finally {
        if (byteArrOutputStream != null) {
            byteArrOutputStream.close();
        }
    }

}

private Image makeThumbnail(final Image originalImage, final int maxWidth, final int maxHeight) throws Exception {
    // ImageOveserve is ingnored for BufferedImages
    final int photoWidth = originalImage.getWidth(null);
    final int photoHeight = originalImage.getHeight(null);

    int thumbWidth = maxWidth;
    int thumbHeight = maxHeight;
    final double thumbRatio = (double) thumbWidth / (double) thumbHeight;
    final double photoRatio = (double) photoWidth / (double) photoHeight;

    if (thumbRatio < photoRatio)
        thumbHeight = (int) (thumbWidth / photoRatio);
    else
        thumbWidth = (int) (thumbHeight * photoRatio);

    // Checking if the photo's size is smaller than thumbnail's size: getting the original size
    if (photoWidth < thumbWidth) {
        thumbWidth = photoWidth;
    }
    if (photoHeight < thumbHeight) {
        thumbHeight = photoHeight;
    }

    final BufferedImage thumbnailBufferedImage = new BufferedImage(thumbWidth, thumbHeight, BufferedImage.TYPE_INT_RGB);
    final Graphics2D graphics2D = thumbnailBufferedImage.createGraphics();

    // Best Quality Render Hints!
    graphics2D.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BICUBIC);
    graphics2D.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
    graphics2D.setRenderingHint(RenderingHints.KEY_FRACTIONALMETRICS, RenderingHints.VALUE_FRACTIONALMETRICS_ON);
    graphics2D.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
    graphics2D.setRenderingHint(RenderingHints.KEY_COLOR_RENDERING, RenderingHints.VALUE_COLOR_RENDER_QUALITY);
    graphics2D.setRenderingHint(RenderingHints.KEY_ALPHA_INTERPOLATION,
            RenderingHints.VALUE_ALPHA_INTERPOLATION_QUALITY);

    final AffineTransform t = new AffineTransform();
    t.scale((double) thumbWidth / photoWidth, (double) thumbHeight / photoHeight);

    graphics2D.setBackground(BKGROUND_COLOR);
    final boolean complete = graphics2D.drawImage(originalImage, t, this);

    if (!complete) {
        while (!imageLoaded) {
            try {
                wait(100);
            } catch (InterruptedException ie) {
            }
        }
    }

    graphics2D.dispose();

    return thumbnailBufferedImage;
}

private synchronized ByteArrayOutputStream makeThumbnail(final InputStream originalImageStream, final int maxWidth,
        final int maxHeight) throws Exception {

    SeekableStream seekableStream = SeekableStream.wrapInputStream(originalImageStream, true);
    RenderedOp reop = JAI.create("stream", seekableStream);
    Image photo = reop.getAsBufferedImage();

    final BufferedImage thumbnail = (BufferedImage) makeThumbnail(photo, maxWidth, maxHeight);

    final ByteArrayOutputStream byteArrayStream = new ByteArrayOutputStream();
    ImageIO.write(thumbnail, GlobalResourceUtils.getFileExtension(), byteArrayStream);

    return byteArrayStream;
}

@Override
public boolean imageUpdate(Image img, int infoflags, int x, int y, int width, int height) {
    if (infoflags != ALLBITS) {
        // Image has not finished loading!
        // Return true to tell the image loading thread to keep drawing until image fully loads.
        return true;
    } else {
        imageLoaded = true;
        return false;
    }
}

}

希望对您有所帮助:)

使用 Selenium Webdriver TakesScreenshot 方法捕获 base64 图像。我可以减小图像尺寸吗？

Using Selenium Webdriver TakesScreenshot method to capture a base64 image. Can I reduce the image size?

java

base64

selenium

screenshot

image