Java 9 新特性 – 多分辨率图像 API

扫码关注公众号:Java 技术驿站

发送:vip
将链接复制到本浏览器,永久解锁本站全部文章

【公众号:Java 技术驿站】 【加作者微信交流技术,拉技术群】

Java 9 引入了一种新的多分辨率图像 API,它支持具有不同分辨率变体的多个图像

这些 API 允许将具有不同分辨率的一组图像用作单个多分辨率图像

方法 说明
getResolutionVariant(doubledestImageWidth,doubledestImageHeight) 获取特定图像,该图像是表示指定大小的逻辑图像的最佳变体
getResolutionVariants() 以可读列表的形式返回所有分辨率变体

接下来我们就来看看两个 API 如何使用吧。

假设存在三张图片

![HTML5.png][] ![HTML5 (1).png][HTML5.png] ![HTML5 (2).png][HTML5.png]

它们的地址分别为

    https://www.twle.cn/static/upload/img/2018/09/03/20180903060845_4.png

    https://www.twle.cn/static/upload/img/2018/09/03/20180903060900_4.png

    https://www.twle.cn/static/upload/img/2018/09/03/20180903060914_4.png

在当前的工作区中创建一个文件 MultiResolutionTester.java 并输入以下内容

    import java.io.IOException;
    import java.net.URL;
    import java.net.MalformedURLException;
    import java.util.ArrayList;
    import java.util.List;
    import java.awt.Image;
    import java.awt.image.MultiResolutionImage;
    import java.awt.image.BaseMultiResolutionImage;

    import javax.imageio.ImageIO;

    public class MultiResolutionTester {
       public static void main(String[] args) throws IOException, MalformedURLException {

          List<String> imgUrls = List.of("https://www.twle.cn/static/upload/img/2018/09/03/20180903060845_4.png",
             "https://www.twle.cn/static/upload/img/2018/09/03/20180903060900_4.png",
             "https://www.twle.cn/static/upload/img/2018/09/03/20180903060914_4.png");

          List<Image> images = new ArrayList<Image>();

          for (String url : imgUrls) {
             images.add(ImageIO.read(new URL(url)));
          }

          // read all images into one multiresolution image
          MultiResolutionImage multiResolutionImage = 
             new BaseMultiResolutionImage(images.toArray(new Image[0]));

          // get all variants of images
          List<Image> variants = multiResolutionImage.getResolutionVariants();

          System.out.println("Total number of images: " + variants.size());

          for (Image img : variants) {
             System.out.println(img);
          }

          // get a resolution-specific image variant for each indicated size
          Image variant1 = multiResolutionImage.getResolutionVariant(156, 45);
          System.out.printf("\nImage for destination[%d,%d]: [%d,%d]", 
             156, 45, variant1.getWidth(null), variant1.getHeight(null));

          Image variant2 = multiResolutionImage.getResolutionVariant(311, 89);
          System.out.printf("\nImage for destination[%d,%d]: [%d,%d]", 311, 89, 
             variant2.getWidth(null), variant2.getHeight(null));

          Image variant3 = multiResolutionImage.getResolutionVariant(622, 178);
          System.out.printf("\nImage for destination[%d,%d]: [%d,%d]", 622, 178, 
             variant3.getWidth(null), variant3.getHeight(null));

          Image variant4 = multiResolutionImage.getResolutionVariant(300, 300);
          System.out.printf("\nImage for destination[%d,%d]: [%d,%d]", 300, 300, 
             variant4.getWidth(null), variant4.getHeight(null));
       }  
    }

运行结果如下

    [yufei@www.twle.cn java9]$ javac MultiResolutionTester.java && java MultiResolutionTester
    Total number of images: 3
    BufferedImage@c267ef4: type = 6 ColorModel: #pixelBits = 32 numComponents = 4 color space = java.awt.color.ICC_ColorSpace@32eff876 transparency = 3 has alpha = true isAlphaPre = false ByteInterleavedRaster: width = 32 height = 32 #numDataElements 4 dataOff[0] = 3
    BufferedImage@9f116cc: type = 6 ColorModel: #pixelBits = 32 numComponents = 4 color space = java.awt.color.ICC_ColorSpace@32eff876 transparency = 3 has alpha = true isAlphaPre = false ByteInterleavedRaster: width = 64 height = 64 #numDataElements 4 dataOff[0] = 3
    BufferedImage@12468a38: type = 6 ColorModel: #pixelBits = 32 numComponents = 4 color space = java.awt.color.ICC_ColorSpace@32eff876 transparency = 3 has alpha = true isAlphaPre = false ByteInterleavedRaster: width = 128 height = 128 #numDataElements 4 dataOff[0] = 3

    Image for destination[156,45]: [128,128]
    Image for destination[311,89]: [128,128]
    Image for destination[622,178]: [128,128]
    Image for destination[300,300]: [128,128]

可以看到,这些 API 还会非常的有趣的

[HTML5.png]:


来源:https://www.twle.cn

赞(0) 打赏
版权归原创作者所有,任何形式的转载请联系博主:daming_90:Java 技术驿站 » Java 9 新特性 – 多分辨率图像 API

评论 抢沙发

  • 昵称 (必填)
  • 邮箱 (必填)
  • 网址

觉得文章有用就打赏一下文章作者

支付宝扫一扫打赏

微信扫一扫打赏