java - BitMap からの BITMAPFILEHEADER と BITMAPINFOHEADER の読み取り

Question

C++ Win32 アプリを Java に変換しています (Linux の場合) bitmap の BITMAPFILEHEADER と BITMAPINFOHEADER を読み取る必要があります。Windowsに特化したjna（Javaネイティブアクセス）ライブラリを見つけました（と思います）。誰かアイデアはありますか？

Answer 1

Webで検索した後、これらの構造体を自分で実装し、ビットマップファイルをバイト配列に読み取り、それらをクラスデータメンバーに解析することにしました。コードは次のとおりです

public class BitmapFileHeader {

char[] bfType;
int bfSize;
short bfReserved1;
short bfReserved2;
int bfOffBits;

private BitmapFileHeader() {

}

public static BitmapFileHeader readFromImage(byte[] image) {

    BitmapFileHeader bitmap = new BitmapFileHeader();

    bitmap.bfType = new char[2];
    int index = 0;
    bitmap.bfType[0] = (char) image[index++];
    bitmap.bfType[1] = (char) image[index++];

    bitmap.bfSize = (image[index + 3] & 0xff) << 24 | (image[index + 2] & 0xFF) << 16 | (image[index + 1] & 0xFF) << 8
            | (image[index + 0] & 0xFF);
    index += 4;

    bitmap.bfReserved1 = (short) (((image[index + 1] & 0xFF) << 8) | (image[index + 0] & 0xFF));
    index += 2;

    bitmap.bfReserved2 = (short) (((image[index + 1] & 0xFF) << 8) | (image[index + 0] & 0xFF));
    index += 2;

    bitmap.bfOffBits = (image[index + 3] & 0xff) << 24 | (image[index + 2] & 0xFF) << 16 | (image[index + 1] & 0xFF) << 8
            | (image[index + 0] & 0xFF);

    return bitmap;

}

}

public class BitmapInfoHeader {

int biSize;
long biWidth;
long biHeight;
short biPlanes;
short biBitCount;
int biCompression;
int biSizeImage;
long biXPelsPerMeter;
long biYPelsPerMeter;
int biClrUsed;
int biClrImportant;

private BitmapInfoHeader() {

}

public static BitmapInfoHeader readFromImage(byte[] image) {

    BitmapInfoHeader bitmap = new BitmapInfoHeader();
    // LittleEndian order ...
    int index = 14;

    bitmap.biSize = (image[index + 3] & 0xff) << 24 | (image[index + 2] & 0xFF) << 16 | (image[index + 1] & 0xFF) << 8
            | (image[index + 0] & 0xFF);
    index += 4;

    bitmap.biWidth = ((image[index + 3] & 0xff) << 24) | (image[index + 2] & 0xFF) << 16 | (image[index + 1] & 0xFF) << 8
            | (image[index + 0] & 0xFF);
    index += 4;

    bitmap.biHeight = (image[index + 3] & 0xff) << 24 | (image[index + 2] & 0xFF) << 16 | (image[index + 1] & 0xFF) << 8
            | (image[index + 0] & 0xFF);
    index += 4;

    bitmap.biPlanes = (short) (((image[index + 1] & 0xFF) << 8) | (image[index + 0] & 0xFF));
    index += 2;

    bitmap.biBitCount = (short) (((image[index + 1] & 0xFF) << 8) | (image[index + 0] & 0xFF));
    index += 2;

    bitmap.biCompression = (image[index + 3] & 0xff) << 24 | (image[index + 2] & 0xFF) << 16 | (image[index + 1] & 0xFF) << 8
            | (image[index + 0] & 0xFF);
    index += 4;

    bitmap.biSizeImage = (image[index + 3] & 0xff) << 24 | (image[index + 2] & 0xFF) << 16 | (image[index + 1] & 0xFF) << 8
            | (image[index + 0] & 0xFF);
    index += 4;

    bitmap.biXPelsPerMeter =
    // ByteBuffer.wrap(image, index, index +
    // 4).order(ByteOrder.LITTLE_ENDIAN).getLong();
    (int) (image[index + 3] & 0xff) << 24 | (image[index + 2] & 0xFF) << 16 | (image[index + 1] & 0xFF) << 8 | (image[index + 0] & 0xFF);
    index += 4;

    bitmap.biYPelsPerMeter = 
            //ByteBuffer.wrap(image, index, index + 4).order(ByteOrder.LITTLE_ENDIAN).getLong();
    (int) (image[index + 3] & 0xff) << 24 | (image[index + 2] & 0xFF) << 16 | (image[index + 1] & 0xFF) << 8 | (image[index + 0] & 0xFF);
    index += 4;

    bitmap.biClrUsed = (image[index + 3] & 0xff) << 24 | (image[index + 2] & 0xFF) << 16 | (image[index + 1] & 0xFF) << 8
            | (image[index + 0] & 0xFF);
    index += 4;

    bitmap.biClrImportant = (image[index + 3] & 0xff) << 24 | (image[index + 2] & 0xFF) << 16 | (image[index + 1] & 0xFF) << 8
            | (image[index + 0] & 0xFF);
    index += 4;

    index += 10;
    return bitmap;

}

}