java - 如何设置 jCaptcha 生成的验证码中文本的字体样式

Question

我正在使用 jcaptcha-all-1.0-RC6 生成验证码图像。

相同的代码片段如下

          captchaService = new DefaultManageableImageCaptchaService();
          logger.info(" After creating instance  getCaptcha ");
          long id = System.currentTimeMillis();
          String captchaId = String.valueOf(id);

          logger.info(" getCaptcha Id " + captchaId);

          logger.info("***********Coming into captcha service***************************************************");
          BufferedImage challenge = captchaService
                       .getImageChallengeForID(captchaId);
          WritableRaster raster = challenge.getRaster();
        ColorModel model = challenge.getColorModel();
          challenge.setRGB(0,25,51);

          logger.debug("challenge:" + challenge);
          ByteArrayOutputStream outputStream = new ByteArrayOutputStream();

          ImageIO.write(challenge, "jpeg", outputStream);

          outputStream.close();
          outputStream.flush();
          byte[] res = outputStream.toByteArray();

          String encodedImage = Base64.encodeBase64String(res);

但是我得到的图像质量不是很好。我们可以做些什么来获得更好的图像质量和更好的可读性吗？

甚至更改字体样式也很有用。对此的任何帮助也会很有用

Answer 1

要通过配置更改图像，您必须扩展 ListImageCaptchaEngine 并使用 Generator :

• 文字生成器
• 颜色生成器
• 后台生成器

• 字体生成器

  public class MyImageCaptchaEngine extends ListImageCaptchaEngine {
  
  @Override
  protected void buildInitialFactories() {
  
      WordGenerator wgen = new RandomWordGenerator("ABCDEFGHIJKLMNOPQRSTUVWXYZ123456789");
      RandomRangeColorGenerator cgen = new RandomRangeColorGenerator(new int[] { 0, 255 }, new int[] { 20, 100 }, new int[] { 20, 100 });
  
      TextPaster textPaster = new RandomTextPaster(new Integer(4), new Integer(5), cgen, Boolean.TRUE);
  
      BackgroundGenerator backgroundGenerator = new UniColorBackgroundGenerator(new Integer(240), new Integer(50), new Color(252,252,253));
  
  
      Font[] fontsList = new Font[] { new Font("Helvetica", Font.TYPE1_FONT, 10), new Font("Arial", 0, 14), new Font("Vardana", 0, 17), };
  
      FontGenerator fontGenerator = new RandomFontGenerator(new Integer(18), new Integer(30), fontsList);
      WordToImage wordToImage = new ComposedWordToImage(fontGenerator, backgroundGenerator, textPaster);
          this.addFactory(new GimpyFactory(wgen, wordToImage));
      }
  }
  

并使用它

ImageCaptchaService instance = new DefaultManageableImageCaptchaService(
            new FastHashMapCaptchaStore(),
            new MyImageCaptchaEngine(),
            180,
            100000,
            75000);