2 Letter forms

We have learned how to build shapes from straight lines and how to draw those lines onto a screen built from pixels or onto paper using ink. If we only ever drew our shapes at one size, we could just use enough tiny little straight lines to build up any shape, including curved ones. However, we might like to draw our shapes at different sizes or display them on devices with different resolutions (there may be 1,200 dots per inch on a commercial printer, for example, but only 200 dots per inch on a computer screen). We don’t really want to store a hundred little lines and their coordinates to describe a circle. We want just to say “a circle of radius 20pt at coordinates (200, 300),” for example. In this chapter, we will learn how to convert descriptions like this into the sets of ink dots or pixels needed to make up an image on paper or screen.

2.1 Straight and curved lines

2.2 Computerized curves

2.3 Complications

2.4 Problems

2.5 Summary