Scaling image of ImageView while maintaining center point in same place

Question

I have set a prescaled Bitmap as ImageView\'s source. Then I\'ve read Matrix of an ImageView and shift Bitmap of an ImageView via matrix.postTranslate(shi

Answer 1

Maybe this can be helpful:

If you got two fingers on screen, you can get the event of the two fingers and get the mid point:

PointF mid;
MotionEvent event;
float x = event.getX(0) - event.getX(1);
float y = event.getY(0) - event.getY(1);
mid.set(x / 2, y / 2);

Then you can set the scalation having the mid point in the center of the screen:

matrix.postScale(scale, scale, mid.x, mid.y);

Answer 2

Take a look at my question here regarding creating a zoomable ViewGroup. I've described code snippets from my end solution, and some of it might be helpful.

Extending RelativeLayout, and overriding dispatchDraw() to create a zoomable ViewGroup