Question

I know how to move a layer based on touch. But I would also like to be able to rotate the image.

Is there any sample code that shows how to do this? Or can anyone give me some advice?

Thanks!

Answer 1

The simplest way to do this is using the layer’s transform property:

float   angle = M_PI;  //rotate 180°, or 1 π radians layer.transform = CATransform3DMakeRotation(angle, 0, 0.0, 1.0); 

The first argument to the CATransform3DMakeRotation function is the amount to rotate, in radians. The next three describe the vector around which to rotate. This is describing a vector in the z-axis, so effectively perpendicular to the screen. This will rotate the layer so it’s upside down.