title: Merging CVPixelBuffers
body: <p>I have CVPixelBuffers of 2 images. I want to merge the two such that the second image is on top of the first one at the co-ordinates I want. Appreciate if anyone can guide me in that.</p>
  
  <p>I don't want to use context draws as I'm trying to lower the CPU utilization. The images would be screenshots that gets processed so it's real-time and doing thousands of context draws increases CPU utilization.</p>