Core Graphics, Chapter 1. The Oracle Method for Drawing
A bitmap as an answer key, and the byte that would not round.
Core Graphics
Core Graphics, Chapter 2. Pixels, Bytes and Coordinates
You will be able to describe a bitmap as nothing more than a long block of bytes with a few numbers that say how to read it.
Core Graphics, Chapter 3. Color, Alpha and Compositing
You will be able to say what premultiplied alpha is, in words a child could follow, and compute the stored byte for any color byte and alpha byte, exactly, by hand.
Core Graphics, Chapter 4. Paths
A shape is a list of five kinds of step, and the rules for walking it.
Core Graphics, Chapter 5. Curves
Four points, a handful of straight pieces, and the match that got worse when the cut got finer.
Core Graphics, Chapter 6. Filling
Why an edge pixel has the value it has, and how the context decides what is inside.
Core Graphics, Chapter 7. Strokes
You will be able to say, for a line of any width at any position, which pixel rows it lights and with what bytes, and work the answer out by hand.
Core Graphics, Chapter 8. Transforms and the Graphics State
You will be able to read the six numbers of a transform as three arrows on a sheet of graph paper, and say, for any list of translate, scale and rotate calls, which order they happen in and which six numbers they leave behind.
Core Graphics, Chapter 9. Clipping
You will be able to say what a clip is, as a byte for every pixel, and work out the edge pixel of a rectangle clip, of a fill, and of the two together, by hand, to the last byte.
Core Graphics, Chapter 10. Gradients
You will be able to say what a gradient is, in words a child could follow: some colors pinned at some places, and a rule for the color in between.
Core Graphics, Chapter 11. Blend Modes and Shadows
You will be able to say what a blend mode is: for the twelve separable modes, a function of the source pixel and the backdrop pixel, on premultiplied bytes, with one piece that depends on the mode and two that do not.
Core Graphics, Chapter 12. Images and Resampling
You will be able to say how drawing an image into a rectangle becomes one question per destination pixel: where in the picture is the center of this pixel, and what color is there.
Core Graphics, Chapter 13. Putting It Together: One Drawing, Several Outputs
A rectangle, a stroke, a curve, a gradient and a shadow, written three ways, and a playbook for the whole book.
