INTRODUCTION
Artist's Tools
Functions, local and global parameters, procedures with multiple parameters. The resolution of text and characters in varying modes; pixels and graphics resolution; text and graphics windows; the use of 'split screen' graphics; the first use of VDU commands; setting the graphics origin.
CHAPTER 1
Turtle Graphics 1
The drawing of a shape with normal BASIC commands, and problems therewith; the idea of an intrinsic geometry, dependent upon the internal structure of a shape; turtle geometry as an intrinsic geometry. The basic turtle commands MOVE and TURN; Version 1.1 of my Turtle Graphics routines.
CHAPTER 2
Turtle Geometry
Angles and ratios of sides are the key intrinsic aspects of geometry; the trigonometrical ratios, sine, cosine and tangent; measuring angles in degrees and radians. How the turtle graphics routines use trigonometrical ratios. Drawing regular polygons; an examination of different plotting styles.
CHAPTER 3
Turtle Graphics II
Modes 1 and 5, the four colour modes; the design of the colours to be used by multi-coloured turtle graphics. Implementing multi-coloured turtles; example effects, and the game NORT.
CHAPTER 4
Driving Graphics
The VDU command, and what it is; the reasoning behind ASCII codes; control codes on computers. Routines to assist in the design of shapes; saving the character routines as ASCII files; saving and loading user-designed shapes
CHAPTER 5
Drawing Charts and Graphs
The normal distribution, the Central Limit Theorem; a simulation of random sampling; the drawing of histograms and frequency polygons, using graphics windows; the effects of sample size, and number of categories.
CHAPTER 6
Turtle Graphics III
The square as a special rectangle; modifying turtle graphics to allow simple sketching of designs; a rectangle is a stretched square, and an ellipse is a stretched circle.
CHAPTER 7
Generative Graphics
Programming style, creative programming does not follow rules; ideas for extensions to the work in this book; suggested reading; Cities in Flight.