@Override
        public void onScaleEnd(ScaleGestureDetector detector) {
            super.onScaleEnd(detector);
            setState(State.NONE);
            boolean animateToZoomBoundary = false;
            float targetZoom = normalizedScale;
            if (normalizedScale > maxScale) {
                targetZoom = maxScale;
                animateToZoomBoundary = true;

            } else if (normalizedScale < minScale) {
                targetZoom = minScale;
                animateToZoomBoundary = true;
            }

            if (animateToZoomBoundary) {
                DoubleTapZoom doubleTap = new DoubleTapZoom(targetZoom, viewWidth / 2, viewHeight / 2, true);
                compatPostOnAnimation(doubleTap);
            }
        }
ScaleListener detects user two finger scaling and scales image.

@author Ortiz
app/src/main/java/home/smart/fly/animations/customview/gallery/TouchImageView.java