Programming with Quartz

Chapter 12 Creating Bits

There are two ways to capture drawing in Quartz—through drawing commands or by creating bitmap raster data (or bits). A PDF representation of Quartz drawing captures drawing commands in their most abstract form. The commands execute when you view the content, which means you can choose the resolution of a PDF document at viewing time. You can change the resolution of the content as you view it and the content still appears sharp.

Bitmap image formats, in contrast, represent a pre-rendered (or rasterized) form of Quartz drawing. You set the image resolution when you create the image content. Drawing the image at the original size produces good fidelity, but if you zoom in on the image, you’ll see artifacts because the ...