crazymichel1's profile - activity

Here is my working java code for Haris answer:

`

 /**

 * Make the black background of a PNG-Bitmap-Image transparent.
 * code based on example at http://j.mp/1uCxOV5
 * @Param image png bitmap image
 * @return output image
 */

private static Bitmap makeBlackTransparent(Bitmap image) {
    // convert image to matrix
    Mat src = new Mat(image.getWidth(), image.getHeight(), CvType.CV_8UC4);
    Utils.bitmapToMat(image, src);

    // init new matrices
    Mat dst = new Mat(image.getWidth(), image.getHeight(), CvType.CV_8UC4);
    Mat tmp = new Mat(image.getWidth(), image.getHeight(), CvType.CV_8UC4);
    Mat alpha = new Mat(image.getWidth(), image.getHeight(), CvType.CV_8UC4);

    // convert image to grayscale
    Imgproc.cvtColor(src, tmp, Imgproc.COLOR_BGR2GRAY);

    // threshold the image to create alpha channel with complete transparency in black background region and zero transparency in foreground object region.
    Imgproc.threshold(tmp, alpha, 100, 255, Imgproc.THRESH_BINARY);

    // split the original image into three single channel.
    List<Mat> rgb = new ArrayList<Mat>(3);
    Core.split(src, rgb);

    // Create the final result by merging three single channel and alpha(BGRA order)
    List<Mat> rgba = new ArrayList<Mat>(4);
    rgba.add(rgb.get(0));
    rgba.add(rgb.get(1));
    rgba.add(rgb.get(2));
    rgba.add(alpha);
    Core.merge(rgba, dst);

    // convert matrix to output bitmap
    Bitmap output = Bitmap.createBitmap(image.getWidth(), image.getHeight(), Bitmap.Config.ARGB_8888);
    Utils.matToBitmap(dst, output);
    return output;
}`

adding opencv library-2.4.x.jar solved it for me: http://answers.opencv.org/question/29422/the-import-orgopencvandroid-cannot-be-resolved/?answer=38710#post-id-38710me

and in addition to autodev101s solution (which worked for me) make sure that you do not copy the samples into your workspace but just reference them, otherwise you get a couple of further errors

Sorry if the answer is too obvious. I ask because a friend of mine said it would not be possible. I do not need to read up on the subject and start coding if the answer is no..