Ok i suppose it's very easy.
I want to do this : selecting a zone in a video by clicking it, i want to zoom considering the click point as the CENTER of my zone.
So, my weak sense of logic would be :
- calculate the size of zoomed screen related to zoom (resolution / zoom) for x / y
- to get the center point, substract 1/2 of that new x value and add 1/2 of the y value
Result : no. not at all. try again....