Rotate image to point

0
votes

I have the following:

CGPoint pos //center of an image
CGPoint target //a point, somewhere in the coordinate system
float rotation //the current rotation of the image to the x-axis, clockwise, so "right" would be 90°

Now I want the image to rotate around it's centerpoint (pos) so that it looks directly towards the targetpoint.

My idea was: Calculate the angle corresponding to the x-axis, subtract rotation, and then rotate it.

Two things:

1.) I fail at calculating the angle. (Yes, I know it's all in rad...)

2.) What's best for rotating?

  • CGAffineTransform? But then I'd need an imageView
  • Or: save context, set origin to center of image, rotate context, draw image, restore context? More complicated, but no imageview neeeded...
1
objective-cios4image-rotation

1 Answers

0
votes

Draw it on a CALayer, and move the layer around anyway you like.