chapter  18
24 Pages

◾ Manipulating Images

Learning goal: You can compose images from geometrical shapes and text. 18.1 IN THIS CHAPTER YOU WILL LEARN

• How to draw images with the Python Imaging Library

• How to draw a schematic image of a plasmid

• How to draw geometrical shapes

• How to add text to an image

• How to combine several pictures to a single image

• How to resize an image

• How to convert a color image to a black-and-white image

18.2 STORY: PLOT A PLASMID One of the rst articial plasmids was constructed in 1977 by Francisco Bolivar and Raymond Rodriguez. It consists of 4,361 DNA base pairs, a replication origin, a gene for ampicillin resistance, and one gene for tetracycline resistance. e plasmid contains many restriction sites and thus serves as a base for constructing genetic vectors.