最直接的方法,可能是使用ByteBuffer
来交换字节顺序,并创建一个新的short
数组来保存像素数据。
然后将(short
)像素数据包装在DataBufferUShort
中。创建一个匹配的WritableRaster
和ColorModel
,最后从中创建一个BufferedImage
。该图像应与上面代码中的图像(BufferedImage.TYPE_USHORT_GRAY
)相同,但创建速度稍快,因为您只需复制一次像素(而不是代码中的两次)。
int w = 2;
int h = 2;
int stride = 1;
byte[] rawBytes = {0x21, 0x27, 0x33, (byte) 0xF6, 0x28, (byte) 0xF3, (byte) 0x27, (byte) 0xF2};
short[] rawShorts = new short[rawBytes.length/2];
ByteBuffer.wrap(rawBytes)
.order(ByteOrder.LITTLE_ENDIAN)
.asShortBuffer()
.get(rawShorts);
DataBuffer dataBuffer = new DataBufferUShort(rawShorts, rawShorts.length);
WritableRaster raster = Raster.createInterleavedRaster(dataBuffer, w, h, w * stride, stride, new int[]{0}, null);
ColorModel colorModel = new ComponentColorModel(ColorSpace.getInstance(ColorSpace.CS_GRAY), false, false, Transparency.OPAQUE, DataBuffer.TYPE_USHORT);
BufferedImage image = new BufferedImage(colorModel, raster, colorModel.isAlphaPremultiplied(), null);
另外,稍微令人费解,但可能更快的方式(如你不要复制的支持像素阵列的话),是创建一个自定义SampleModel
与MSB(小端)字节数据的作品,但将它们公开为TYPE_USHORT
。这将创建一个TYPE_CUSTOM
图像。
int w = 2, h = 2, stride = 2;
byte[] rawBytes = {0x21, 0x27, 0x33, (byte) 0xF6, 0x28, (byte) 0xF3, (byte) 0x27, (byte) 0xF2};
DataBuffer dataBuffer = new DataBufferByte(rawBytes, rawBytes.length);
SampleModel sampleModel = new ComponentSampleModel(DataBuffer.TYPE_USHORT, w, h, stride, w * stride, new int[] {0}) {
@Override
public Object getDataElements(int x, int y, Object obj, DataBuffer data) {
if ((x < 0) || (y < 0) || (x >= width) || (y >= height)) {
throw new ArrayIndexOutOfBoundsException("Coordinate out of bounds!");
}
// Simplified, as we only support TYPE_USHORT
int numDataElems = getNumDataElements();
int pixelOffset = y * scanlineStride + x * pixelStride;
short[] sdata;
if (obj == null) {
sdata = new short[numDataElems];
}
else {
sdata = (short[]) obj;
}
for (int i = 0; i < numDataElems; i++) {
sdata[i] = (short) (data.getElem(bankIndices[i], pixelOffset + bandOffsets[i] + 1) << 8|
data.getElem(bankIndices[i], pixelOffset + bandOffsets[i]));
}
return sdata;
}
};
ColorModel colorModel = new ComponentColorModel(ColorSpace.getInstance(ColorSpace.CS_GRAY), false, false, Transparency.OPAQUE, DataBuffer.TYPE_USHORT);
WritableRaster raster = Raster.createWritableRaster(sampleModel, dataBuffer, null);
BufferedImage image = new BufferedImage(colorModel, raster, colorModel.isAlphaPremultiplied(), null);
我真的没有看到创建RenderedImage
子类的一个原因。
这真棒,非复制代码减少了我的JVM内存消耗几乎没有,谢谢! – Black0ut