从十六进制字符串 Java 创建 BITMAP 图像

Question

我需要从通过 Excel 宏创建的十六进制字符串创建 BMP 图像（黑白）。 我在这方面的工作经验几乎为零，需要一些帮助。 下面是十六进制字符串，output 十六进制图像示例，以及我正在尝试的小代码片段：

字符串：

001E00FE07FE3FE03C003C003F801FFE03FE007E3E003FE03FFC0FFE0E3E0FFE3FFC3FE03E0000000FF83FFC3FFE300630063006380E180C00003E003FE03FFC0FFE0E3E0FFE3FFC3FE03E00000000003FFE3FFE3FFE01F807F01FC03FFE3FFE3FFE0000000E000E000E3FFE3FFE3FFE000E000E000E0000

要创建的上述字符串的图像：

代码片段：

public void createImageFromHex() throws IOException {
        String hex="001E00FE07FE3FE03C003C003F801FFE03FE007E3E003FE03FFC0FFE0E3E0FFE3FFC3FE03E0000000FF83FFC3FFE300630063006380E180C00003E003FE03FFC0FFE0E3E0FFE3FFC3FE03E00000000003FFE3FFE3FFE01F807F01FC03FFE3FFE3FFE0000000E000E000E3FFE3FFE3FFE000E000E000E0000";

        byte[] imageInByte= ByteString.decodeHex(hex).toByteArray();

        for (byte b : imageInByte) {
            System.out.println("Byte : " + b);

        }
        InputStream in = new ByteArrayInputStream(imageInByte);

        Font font = new Font("Arial", Font.PLAIN, 12);
        BufferedImage img = new BufferedImage(1, 1, BufferedImage.BITMASK);
        Graphics2D g2d = img.createGraphics();
        FontMetrics fm = g2d.getFontMetrics(font);
        g2d.dispose();

        int width = fm.stringWidth(hex);
        int height = fm.getHeight();

        img = new BufferedImage(width, height, BufferedImage.BITMASK);
        g2d = img.createGraphics();
        g2d.setColor(Color.WHITE);
        g2d.fillRect(0, 0, width, height);
        g2d.setColor(Color.BLACK);
        g2d.setFont(font);
        g2d.drawString(hex, 0, fm.getAscent());
        g2d.dispose();

        try {
            ImageIO.write(img, "bmp", new File("Hex.bmp"));
        } catch (IOException ex) {
            ex.printStackTrace();
        }
    } 

Answer 1

这里的线索是十六进制/二进制数据的格式。 您需要从某种规范中，从产生十六进制字符串的设备/软件/服务中了解这一点。 从数据和样本图像来看，我相信@tgdavies 已经正确地对其进行了逆向工程。

每个像素是一位。 白色像素存储为 0，黑色像素存储为 1。每列像素存储为两个字节。 每列自下而上存储。

假设格式是正确的，编写代码来转换它是非常简单的：

public void createImageFromHex() throws IOException {
    // Assumption: hex contains a bitmap format, where
    //   * each pair of bytes is one *column*
    //   * each column is stored "bottom-up" (LSB is bottom pixel, MSB is top pixel)
    String hex = "001E00FE07FE3FE03C003C003F801FFE03FE007E3E003FE03FFC0FFE0E3E0FFE3FFC3FE03E0000000FF83FFC3FFE300630063006380E180C00003E003FE03FFC0FFE0E3E0FFE3FFC3FE03E00000000003FFE3FFE3FFE01F807F01FC03FFE3FFE3FFE0000000E000E000E3FFE3FFE3FFE000E000E000E0000";

    // (result is 120 bytes)
    byte[] imageInByte = ByteString.decodeHex(hex).toByteArray();

    int height = 16; // 16 according to sample
    int width = imageInByte.length / 2; // 60 according to the sample, but as we know each column is 16 bits or 2 bytes, we can calculate it

    // Create a BufferedImage of correct type: For a bitmap this is TYPE_BYTE_BINARY
    BufferedImage img = new BufferedImage(width, height, BufferedImage.TYPE_BYTE_BINARY);

    // Loop over pixels and insert black or white
    for (int x = 0; x < width; x++) {
        for (int y = 0; y < height; y++) {
            int pos = height * x + y;
            int bytePos = pos / 8;
            int bitPos = 7 - (pos % 8);
            byte value = imageInByte[bytePos];

            int bit = (value >> bitPos) & 1;

            // Each pixel is either all white (0) or all black (1)
            int rgb = bit != 0 ? 0x000000 : 0xFFFFFF;
            img.setRGB(x, height - 1 - y, rgb);
        }
    }

    // Write to BMP format
    File output = new File("Hex.bmp");
    if (!ImageIO.write(img, "bmp", output)) {
        System.err.printf("Could not write %s in BMP format...%n", output.getAbsolutePath());
    }
}

结果文件：