uiview rotation keeping 1 coordinate constant

Question

Good Day!

i want to ask that if i want to bring a uiview in front on another view, but i want to bring it by keeping its 1 points constant so that it looks like that only 1 (top) portion moved down. i put my uiview on 90 degrees but i could not figure out the way to bring it horizontal. here is code for uiview

clView.frame = CGRectMake(0,100,258,171);
clView.transform = CGAffineTransformIdentity;
clView.transform = CGAffineTransformMakeRotation(degreesToRadians(90));
[self.view addSubview:clView];

Now it puts my view to 90 degrees but i could not bring it down with animation keeping one point constant. like projectile motion. Can somebody help me out ?

Yellow circle part i want to be still and other moving, 90 degress and back to normal

Answer 1

You probably want to set the anchorPoint of the underlying CALayer, to whatever coordinates represent the middle of the yellow circle. So something like:

myView.layer.anchorPoint = CGPointMake(x,y); // where x and y is the middle of the yellow circle.

Once you've set the anchorPoint, transforms will be done about that point.

This page has more detail on this.