Question

我编写了一个类，它可以帮助我从一个大图中获取32x32图像。但我有一个问题。我的班级看起来像这样：

package tool;

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;

public class ImageLoader {

    private String file;
    private BufferedImage image;
    private BufferedImage[][] subImage;

    public ImageLoader(String FILE) {
        file = FILE;
        try {
            image = ImageIO.read(new File(file));
        } catch (IOException e) {
        }

        subImage = new BufferedImage[image.getWidth() / 32][image.getHeight() / 32];
        for (int i = 0; i < image.getWidth() / 32; i++) {
            for (int j = 0; j < image.getHeight() / 32; j++) {
                subImage[i][j] = image.getSubimage(i * 32, j * 32, (1 + i) * 32, (1 + j) * 32);
            }
        }
    }

    public BufferedImage getSubImage(int X, int Y) {
        return subImage[X][Y];
    }
}

如果我这样做，似乎ImageIO.read(new File(String file))命令阻止使用那个我想绘制图像的Swing对象的paintComponent()。我进行了一些实验，发现当你在getSubImage(int X, int Y)方法中加载图像时，它运行正常。但我想，这不是最明智的想法，因为如果你调用这个方法，你总是会再次加载这个图像。我需要帮助，我如何只加载一次图像，并且Swing对象正确地绘制了它。

提前致谢。

Answer 1

编写缩略图并将其加载回JLabel。

//get the large file and create a new 32x32 thumbnail 
BufferedImage sourceImage = ImageIO.read(new FileInputStream("c://filename"));
Image thumbnail = sourceImage.getScaledInstance(32, 32, Image.SCALE_SMOOTH);
BufferedImage bufferedThumbnail = new BufferedImage(thumbnail.getWidth(null),
                                                thumbnail.getHeight(null),
                                                BufferedImage.TYPE_INT_RGB); 
bufferedThumbnail.getGraphics().drawImage(thumbnail, 0, 0, null);
//read the file back
ImageIO.write(bufferedThumbnail, "jpeg", outputStream);


//read the file back  
image = ImageIO.read(new File(path));
JLabel picLabel = new JLabel(new ImageIcon(image));

JAVA使用ImageIO.read和paintComponents（）

1 个答案: