Java ImageIO: How can I read a BufferedImage from file, so that it uses DataBufferFloat?

Question

Hello, everyone!

I need to read a BufferedImage from file, which doesn't use DataBufferInt (as normally), but DataBufferFloat.

Please note: I don't just need some standalone DataBufferFloat, but really a BufferedImage with underlying DataBufferFloat.

The API around these things is very complex, I just can't find how to do this.

Please help.

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EDIT
Found out what is not working:

DataBufferDouble dbd = new DataBufferDouble(destWidth * destHeight * 4);

// Exception here:
// java.lang.IllegalArgumentException: Unsupported data type 5
WritableRaster wr = WritableRaster.createPackedRaster(
    dbd, destWidth, destHeight, 32, new Point(0, 0));

BufferedImage bi = new BufferedImage(ColorModel.getRGBdefault(),
    wr, false, (Hashtable<?, ?>) null);

Answer 1

createPackedRaster is not appropriate for this. It creates a Raster with a SinglePixelPackedSampleModel, which stores r/g/b/a values in bit fields within an int, so its transferType can only be an integral type.

You probably want a generic raster with a PixelInterleavedSampleModel e.g.

DataBufferDouble dbd = new DataBufferDouble(destWidth * destHeight * 4);

SampleModel sm = new PixelInterleavedSampleModel(DataBuffer.TYPE_DOUBLE, destWidth, destHeight, 4, destWidth * 4, new int[] {2, 1, 0, 3});

WritableRaster wr = WritableRaster.createWritableRaster(sm, dbd, null);

ColorModel cm = new ComponentColorModel(ColorSpace.getInstance(ColorSpace.CS_LINEAR_RGB), true, true, ColorModel.TRANSLUCENT, DataBuffer.TYPE_FLOAT);

BufferedImage bi = new BufferedImage(cm, wr, true, new Hashtable<Object, Object>());