convert Mat to Bitmap Opencv for Android

Question

I\'m trying to covert a MAt to a Bitmap use following code :

    Bitmap bmp = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
    Mat tmp = new          


        

Answer 1

Try this code for mat to bitmap conversion

**Mat mRgba;
public void onCameraViewStarted(int width, int height) {
        mRgba = new Mat(height, width, CvType.CV_8UC4);
}
public Mat onCameraFrame(Mat inputFrame) {
   inputFrame.copyTo(mRgba);
   return mRgba;
}
private void captureBitmap(){
       bitmap = Bitmap.createBitmap(mOpenCvCameraView.getWidth()/4,mOpenCvCameraView.getHeight()/4, Bitmap.Config.ARGB_8888);
    try {
          bitmap = Bitmap.createBitmap(mRgba.cols(), mRgba.rows(), Bitmap.Config.ARGB_8888);
                Utils.matToBitmap(mRgba, bitmap);
               mBitmap.setImageBitmap(bitmap);
               mBitmap.invalidate();
    }catch(Exception ex){
          System.out.println(ex.getMessage());
    }
 }**

Answer 2

1) OpenCV Mat constructor expects <rows, cols> pair instead of <width, height> as its arguments. So you have to change your second line to

Mat tmp = new Mat (height, width, CvType.CV_8U, new Scalar(4));

2) Imgproc.cvtColor can change the dimensions of the tmp object. So it is safe to create a bitmap after the color conversion:

Bitmap bmp = null;
Mat tmp = new Mat (height, width, CvType.CV_8U, new Scalar(4));
try {
    //Imgproc.cvtColor(seedsImage, tmp, Imgproc.COLOR_RGB2BGRA);
    Imgproc.cvtColor(seedsImage, tmp, Imgproc.COLOR_GRAY2RGBA, 4);
    bmp = Bitmap.createBitmap(tmp.cols(), tmp.rows(), Bitmap.Config.ARGB_8888);
    Utils.matToBitmap(tmp, bmp);
}
catch (CvException e){Log.d("Exception",e.getMessage());}