Convert byte array to Mat in JavaCV - scala

Question

Like this:
import org.bytedeco.javacpp.opencv_core.Mat
import org.bytedeco.javacpp.{opencv_core, opencv_imgcodecs}
val jpegRawBytes: Array[Byte] = ??? // this is given, not a problem
val matRaw = new Mat(1, jpegRawBytes.length, opencv_core.CV_8UC1)
??? // mat.put(jpegRawBytes)
val matImg = opencv_imgcodecs.imdecode(matRaw, opencv_imgcodecs.IMREAD_COLOR)
How would I do the second ??? step, putting the Array[Byte] into the Mat?
Here is one, but it looks very inefficient, having to call put for each single byte:
val idxRaw = matRaw.createIndexer[UByteRawIndexer]()
var i = 0
while (i < jpegRawBytes.length) {
idxRaw.put(0, i, jpegRawBytes(i))
i += 1
}

Answer 1

public static Mat toMat(BufferedImage bi) {
OpenCVFrameConverter.ToIplImage cv = new OpenCVFrameConverter.ToIplImage();
Java2DFrameConverter jcv = new Java2DFrameConverter();
return cv.convertToMat(jcv.convert(bi));
}
public static Mat toMat(byte[] bs) {
return toMat(toBufferedImage(bs));
}
public static BufferedImage toBufferedImage(byte[] bs) {
try {
return ImageIO.read(new ByteArrayInputStream(bs));
} catch (IOException ex) {
Logger.getLogger(CEIUtils.class.getName()).log(Level.SEVERE, null, ex);
}
return null;
}