CODEWITHSUNDEEP
androidopencvandroid-imageviewandroid-relativelayout
user3449119
user3449119

Reputation: 61

Select Image area on Image view in Android

I want to select an rect area of an image i.e. of a bitmap which is in the image view . The rect area is defined by the user by touch. It is not like crop. User can select the rect area and then sub-image will be created. I am giving some code below nut it is not independent of devices , I have also incorporated the OpenCv for camculating region of interest , please help me

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

final DragRectView view = (DragRectView) findViewById(R.id.dragRect);
imview1 = (ImageView) findViewById(R.id.imageView1);
bmp = BitmapFactory.decodeResource(getResources(), R.drawable.poll);
imview1.setImageBitmap(bmp);
final Mat mat1=new Mat(bmp.getHeight(),bmp.getWidth(),CvType.CV_8UC4);
Utils.bitmapToMat(bmp, mat1);



if (null != view) {
    view.setOnUpCallback(new DragRectView.OnUpCallback() {
        @Override
        public void onRectFinished(final Rect rect) {


            org.opencv.core.Rect rectmat = new org.opencv.core.Rect(10,20,240,360);



            Mat matroi = new Mat(mat1,rectmat);

            Bitmap bm = Bitmap.createBitmap(matroi.rows(),matroi.cols(),Config.ARGB_8888);
            Utils.matToBitmap(matroi, bm);

            //mat1.copyTo(rectmat);

            Toast.makeText(getApplicationContext(), "Rect is (" + rect.left + ", " + rect.top + ", " + rect.right + ", " + rect.bottom + ")",
                    Toast.LENGTH_LONG).show();
            imview1.setImageBitmap(bm);

        }
    });
}

}

Upvotes: 2

Views: 1971

Answers (1)

Darshan
Darshan

Reputation: 1018

This code will help you draw rectangle using Android.graphics.rect.

public int ImgYOffset;
public int ImgXOffset;
private rectangle_box = null;
final AtomicReference<Point> RectBox_1stCorner = new AtomicReference<Point>();
    final Paint rectPaint = new Paint();
    rectPaint.setColor(Color.rgb(0, 255, 0));
    rectPaint.setStrokeWidth(5);
    rectPaint.setStyle(Style.STROKE);

    setOnTouchListener(new OnTouchListener() {
        @Override
        public boolean onTouch(View v, MotionEvent event) {

            final Point corner = new Point(event.getX() - ImgXOffset, event.getY() - ImgYOffset);
            switch(event.getAction()){
            case MotionEvent.ACTION_DOWN:
                RectBox_1stCorner.set(corner);
                break;
            case MotionEvent.ACTION_UP:
                rectangle_box= new Rect(RectBox_1stCorner.get(), corner);
                break;
            case MotionEvent.ACTION_MOVE:
                final android.graphics.Rect rect = new android.graphics.Rect(
                                (int)RectBox_1stCorner.get().x + ImgXOffset, (int)RectBox_1stCorner.get().y + ImgYOffset, 
                                (int)corner.x + ImgXOffset, (int)corner.y + ImgYOffset);
                final Canvas canvas =_holder.lockCanvas(rect);
                canvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR); // remove old rectangle
                canvas.drawRect(rect, rectPaint);
                _holder.unlockCanvasAndPost(canvas);
                break;
            }

            return true;
        }
    });
}

// if rectangle box is not null then assign this rectangle_box to new MAT or BITMAP object to create a subimage which you want to work with.

Upvotes: 1

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