如何有效地存储像素数据并打包字节数据

Question

我创建了一个简单的类，它将bytes的{​​{1}}编码为BufferedImage的像素。我正在使用一个字节数组，并在写出图像时将每4 bytes打包成ARGB值。我觉得有一种更简单的方法可以做到这一点。我有更好的存储像素数据的方法吗？

代码生成这个微小的图像，但它可以缩放导出*任何*大小→ ←

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;

public class PixelExport {
    private byte[] data;

    private static byte f(int value) { return (byte) value; }

    private static long pack(byte b1, byte b2, byte b3, byte b4) {
        return ((0xFFL & b1) << 24) | ((0xFFL & b2) << 16) |
                ((0xFFL & b3) << 8) | (0xFFL & b4);
    }

    public PixelExport() {
        data = new byte[] {
            // Row 1 - Red with Alpha FF -> 3F
            f(0xFF), f(0xFF), f(0x00), f(0x00),
            f(0xBF), f(0xFF), f(0x00), f(0x00),
            f(0x7F), f(0xFF), f(0x00), f(0x00),
            f(0x3F), f(0xFF), f(0x00), f(0x00),
            // Row 1 - Green with Alpha FF -> 3F
            f(0xFF), f(0x00), f(0xFF), f(0x00),
            f(0xBF), f(0x00), f(0xFF), f(0x00),
            f(0x7F), f(0x00), f(0xFF), f(0x00),
            f(0x3F), f(0x00), f(0xFF), f(0x00),
            // Row 1 - Blue with Alpha FF -> 3F
            f(0xFF), f(0x00), f(0x00), f(0xFF),
            f(0xBF), f(0x00), f(0x00), f(0xFF),
            f(0x7F), f(0x00), f(0x00), f(0xFF),
            f(0x3F), f(0x00), f(0x00), f(0xFF)
        };

        export(data, 4, 3, "foo", "png");
    }

    public void export(byte[] data, int width, int height, String filename, String ext) {
        String fullFilename = String.format("%s.%s", filename, ext);
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);

        for (int i = 0; i < data.length; i+=4) {
            int row = i / (width * 4);
            int col = (i / 4) % width;
            image.setRGB(col, row, (int) pack(data[i], data[i+1], data[i+2], data[i+3]));
        }

        try {
            ImageIO.write(image, ext, new File(fullFilename));
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            System.out.printf("Wrote: %s\n", fullFilename);
        }
    }

    public static void main(String[] args) {
        new PixelExport();
    }
}

我也可以使用ByteBuffer，但这是必要的吗？如果我已经有指数？

ByteBuffer buf = ByteBuffer.wrap(data);
buf.rewind();
while (buf.hasRemaining()) {
    int row = buf.position() / (width * 4);
    int col = (buf.position() / 4) % width;
    image.setRGB(col, row, (int) pack(buf.get(), buf.get(), buf.get(), buf.get()));
}