The image shows the 300 most commonly occurring words in the text. The area of the word indicates the relative frequency of that term. The color shows when in the text the word first occurs -- red is early, green middle and blue later. The brighter the color, the more the word appears in a distinct location -- words that are dark are spread out all over the text. The position and orientation of each term has no analytic meaning. The layout simply fits the tags into a compct layout.
Some code for reading the text, assembling frequencies, building the visaulization and writign the image files is in a single example Java file. It is not intended to be either bulletproof or maintainable -- it was written in an afternoon. With that disclaimer, the file is TagCloudExample.java. The XML specification for a slightly simpler version of the visualization is in the file tagCloud.xml.