ImageTypeSpecifier.java 文件源码

/**
 * Create a grayscale image type specifier, given the number of
 * bits, data type and whether or not the data is signed.
 *
 * @param bits the number of bits used to specify a greyscale value
 * @param dataType a DataBuffer type constant
 * @param isSigned true if this type specifier should support
 * negative values, false otherwise
 *
 * @return a greyscal image type specifier
 *
 * @exception IllegalArgumentException if bits is not 1, 2, 4, 8 or
 * 16
 * @exception IllegalArgumentException if dataType is not
 * DataBuffer.TYPE_BYTE, DataBuffer.TYPE_SHORT or
 * DataBuffer.TYPE_USHORT
 * @exception if bits is larger than the number of bits in the given
 * data type
 */
public static ImageTypeSpecifier createGrayscale (int bits, int dataType,
                                                  boolean isSigned,
                                                  boolean isAlphaPremultiplied)
{
  if (bits != 1 && bits != 2 && bits != 4 && bits != 8 && bits != 16)
    throw new IllegalArgumentException ("invalid bit size");

  if (dataType != DataBuffer.TYPE_BYTE && dataType != DataBuffer.TYPE_SHORT
      && dataType != DataBuffer.TYPE_USHORT)
    throw new IllegalArgumentException ("invalid data type");

  if (dataType == DataBuffer.TYPE_BYTE && bits > 8)
    throw new IllegalArgumentException ("number of bits too large for data type");

  // FIXME: this is probably wrong:
  return new ImageTypeSpecifier (new DirectColorModel (bits, 0xff, 0x0,
                                                       0x0, 0xff),
                                 new MultiPixelPackedSampleModel (dataType,
                                                                  1, 1,
                                                                  bits));
}