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014-十四、Java 9 – 多分辨率图像 API

引言

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
14-十四、Java
14-十四、Java
14-十四、Java

它们的地址分别为


https://static.javajike.com/img/java/jt/java9/1573397953234_20180903060845_4.png https://static.javajike.com/img/java/jt/java9/1573397954301_20180903060900_4.png https://static.javajike.com/img/java/jt/java9/1573397955211_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://static.javajike.com/img/java/jt/java9", "https://static.javajike.com/img/java/jt/java9", "https://static.javajike.com/img/java/jt/java9"); 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


[penglei@www.ycbbs.vip 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

写完了如果写得有什么问题,希望读者能够给小编留言,也可以点击[此处扫下面二维码关注微信公众号](https://www.ycbbs.vip/?p=28 "此处扫下面二维码关注微信公众号")

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标题:014-十四、Java 9 – 多分辨率图像 API

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