Java 9 Multi-Resolution Image API: Responsive Graphics vereenvoudigen

Met Java 9 is een nieuwe multi-resolution image API geïntroduceerd die meerdere afbeeldingen met verschillende resolutievarianten ondersteunt. Deze API stelt een set afbeeldingen met verschillende resoluties in als een enkele multi-resolution image. De belangrijkste operaties zijn:

• Image getResolutionVariant(double destImageWidth, double destImageHeight) – Haalt de specifieke afbeelding op die de beste variant is om deze logische afbeelding op de aangegeven grootte weer te geven.

• List<Image> getResolutionVariants() – Haalt een leesbare lijst van alle resolutievarianten op.

Voorbeeld

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(
            "https://www.tutorialspoint.com/java9/images/logo.png",
            "https://www.tutorialspoint.com/java9/images/mini_logo.png",
            "https://www.tutorialspoint.com/java9/images/large_logo.png");
        List<Image> images = new ArrayList<Image>();
        for (String url : imgUrls) {
            images.add(ImageIO.read(new URL(url)));
        }
        // Lees alle afbeeldingen in één multi-resolution image
        MultiResolutionImage multiResolutionImage = new BaseMultiResolutionImage(images.toArray(new Image[0]));
        // Haal alle varianten op
        List<Image> variants = multiResolutionImage.getResolutionVariants();
        System.out.println("Total number of images: " + variants.size());
        for (Image img : variants) {
            System.out.println(img);
        }
        // Haal resolutie-specifieke variant op voor elke aangegeven grootte
        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));
    }
}

Uitvoer

Total number of images: 3
BufferedImage@7ce6a65d: type = 6 ColorModel: #pixelBits = 32 numComponents = 4 color space =java.awt.color.ICC_ColorSpace@548ad73b transparency = 3 has alpha = true isAlphaPre = false ByteInterleavedRaster: width =311 height = 89 #numDataElements 4 dataOff[0] = 3
BufferedImage@4c762604: type = 6 ColorModel: #pixelBits = 32 numComponents = 4 color space =java.awt.color.ICC_ColorSpace@548ad73b transparency = 3 has alpha = true isAlphaPre = false ByteInterleavedRaster: width =156 height = 45 #numDataElements 4 dataOff[0] = 3
BufferedImage@2641e737: type = 6 ColorModel: #pixelBits = 32 numComponents = 4 color space =java.awt.color.ICC_ColorSpace@548ad73b transparency = 3 has alpha = true isAlphaPre = false ByteInterleavedRaster: width =622 height = 178 #numDataElements 4 dataOff[0] = 3
Image for destination[156,45]: [311,89]
Image for destination[311,89]: [311,89]
Image for destination[622,178]: [622,178]
Image for destination[300,300]: [622,178]