iOS Core Animation: Advanced Techniques

3. Layer Geometry

Let no one unversed in geometry enter here.

Sign above the entrance to Plato’s Academy

Chapter 2, “The Backing Image,” introduced the layer-backing image and the properties used to control its position and scaling within the layer bounds. In this chapter, we look at how the layer itself is positioned and sized with respect to its superlayer and siblings. We also explore how to manage your layer’s geometry and how it is affected by autoresizing and autolayout.

Layout

UIView has three primary layout properties: frame, bounds, and center. CALayer has equivalents called frame, bounds, and position. Why they used “position” for layers and “center” for views will become clear, but they both represent the same value.

The frame represents ...