Find new coordinates of a point after image resize

Question

I've resized my image to newX, newY. Prior to resizing I had a point (x,y). Now that I've resized my image I'd like to know where the point is on the new image. Sounds simple but I'm bad at math. Any ideas?

Answer 1

It is just a matter of ratios:

On the x-axis, you have resized by a ratio Rx = newX/oldX, and by a ratio Ry = newY/oldY on the y-axis.

Therefore, your new coordinates for point (x,y) are (Rx * x, Ry * y).