Resize rotated image to fill a view

Question

I'm trying to resize a UIImage so that it totally covers it's parent view. It's not hard to do this when the image isn't transformed. How do I do it for any arbitrary rotation (e.g., 30 degrees, 97 degrees, 277 degrees, etc.)?

In the example below, I want the flower image to scale just enough so none of the white view is visible. I'd also like the origin as close to 0,0 as possible. In other words, I want want it aligned with the top, left corner.

Any ideas?

Bonus Question:

I'd also like the option of doing an aspect fit so the whole image is visible at the maximum possible size that fits in the white area.

     

Answer 1

Here's a little push in the right direction.

Given that W and H are the width and height of the parent view, and theta is the rotation angle of the image, then the image width (x) can be calculated as

x = W * cos(theta) + H * sin(theta);

From that result, you can calculate the scale factor for the image, which in turn gives you the image height. The rest is left as an exercise for the reader.