How Draw circle on Zoom able and scroll able imageview android?

Question

I am developing an application and requirements are as below.

Display image with pinch zoom and pan.

For this I am using TouchImageview.java from here

And it is working as expected.

Draw solid circle on Image.

This is also working.

public class NavigationViewZoom extends TouchImageView {
    private Paint mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);

    @Override
    public void setImageBitmap(Bitmap bm) {
        super.setImageBitmap(bm);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        canvas.drawCircle(300, 120, 50, mPaint);
    }

    public NavigationViewZoom(Context c) {
        super(c);
        init();
    }

    public NavigationViewZoom(Context c, AttributeSet attrs) {
        super(c, attrs);
        setDrawingCacheEnabled(true);
        init();
    }

    private void init() {

        mPaint.setColor(Color.RED);
        mPaint.setStyle(Paint.Style.FILL);

    }
}

Problem:

Now the problem is, when zoom in/out image after drawing solid circle on canvas the circle position is not managed.

For Example I draw solid circle on position x=100,y=100 after zooming the image the circle should be on same position. So how to get the relative x,y position on zoomed image.

Answer 1

Try using this library. In demo app is shown a feature that seems to do what you want.

CircleView class in the library could be useful.