Contents

Preface
0 Introduction

0.0 About this book
0.1 The two models of the BBC Microcomputer
0.2 Loading, saving and joining programs
0.3 Activities
0.4 Discussion of activities

1 Fundamentals of graphics

1.0 Introduction
1.1 The display modes of a Model B BBC Microcomputer
1.2 Graphics on a Model A BBC Microcomputer
1.3 Getting into a mode
1.4 Addressing pixels
1.5 Activites
1.6 Drawing lines
1.7 Activities
1.8 Drawing simple curves
1.9 Activites
1.10 Discussion of activities

2 Colouring displays

2.0 Introduction
2.1 Available colours
2.2 Setting foreground and background colour for text
2.3 Activities
2.4 Setting foreground and background colours for graphics
2.5 Activities

3 Drawing simple shapes

3.0 Introduction
3.1 Codes for the PLOT statement
3.2 Activities
3.3 Using the PLOT statement
3.4 Activities
3.5 Discussion of activities

4 Programming your own characters

4.0 Introduction
14.1 Designing a programmable character
4.2 Converting the design to code
4.3 Activities
4.4 Printing programmable characters
4.5 Activities
4.6 Composite figures
4.7 Activities
4.8 Multicoloured characters and figures
4.9 Activities
4.10 Discussion of activities

5 Animating displays

5.0 introduction
5.1 The redefinable and absolute colour numbers: a summary
5.2 Redefining colours
5.3 Activities
5.4 Animation
5.5 Activities
5.6 Overlapping images
5.7 Logical operations
5.8 Activities
5.9 Discussion of activities

6 Drawing three dimensional ripple surfaces

6.0 Introduction
6.1 Choosing a function and scaling it
6.2 Activities
6.3 Drawing the surface
6.4 Hidden lines
6.5 Activities
6.6 Discussion of activities

7 Adding perspective

7.0 Introduction
7.1 Drawing the object
7.2 Giving the object perspective
7.3 Rotating the object
7.4 The complete program
7.5 Activities
7.6 Two techniques for hidden line removal
7.7 Activities

8 Extending BBC BASIC for graphics

8.0 Introduction
8.1 Our procedures
8.2 Procedures for enlarged, rotated writing
8.3 Using the procedures for large, rotated writing
8.4 Activities
8.5 Feeding data into programs
8.6 Storing data: arrays
8.7 The core procedures
8.8 Activities
8.9 Discussion of activities

9 Drawing graphs

9.0 Introduction
9.1 Data calculated by the program
9.2 Removal of the cursor from the final display
9.3 Activities
9.4 Data read from DATA statements
9.5 Titles and other labels
9.6 Activities
9.7 Data taken from the INPUT statement
9.8 Forcing the inclusion of the origin
Activities

10 Getting the best straight line

10.0 Introduction
10.1 The equation of a straight line
10.2 The correlation coefficient
10.3 Using PROCbstln
10.4 Activities
10.5 Setting the accuracy of the equation and the correlation coefficient
10.6 Activities

11 Displaying shapes of functions

11.0 Introduction
11.1 Selecting a function for display
11.2 Using the function-drawing program
11.3 The operation of the program
11.4 Activities
11.5 Displaying two functions together
11.6 Activities
11.7 Discussion of activities

12 Drawing histograms

12.0 introduction
12.1 Drawing a simple histogram
12.2 Activities
12.3 Labelling the bars
12.4 Activities
12.5 Drawing solid-looking histograms
12.6 Activities
12.7 Drawing two histograms together
12.8 Activities

13 Drawing pie charts

13.0 Introduction
13.1 Drawing a pie chart
13.2 Activities
13.3 Storing a pie chart
13.4 Activities

14 Displaying statistics

14.0 Introduction
14.1 Some statistical terms
14.2 The statistics program
14.3 Activities
14.4 Superimposing alternative distributions

15 Using Teletext graphics

15.0 Introduction
15.1 Writing in colour
15.2 Colouring the background of a single line of text
15.3 Flashing text
15.4 Making double height characters
15.5 Activities
15.6 Block graphics
15.7 Getting continuity when changing colour
15.8 Composite figures
15.9 Activities
15.10 Using the procedures with Teletext
15.11 Error messages with Teletext graphics programming
15.12 Activities
15.13 Discussion of activities

Appendix 1 Listings for the procedures

Introduction
The listings
Adaptations of the listings for Teletext

Appendix 2 How the procedures work



THE PROCEDURE PROCscale
The operation of PROCscale: smallest and largest values
The operation of PROCscale: co-ordinates for the ends of the axes,
The operation of PROCscale: conversion to screen co-ordinates
The operation of PROCscale: the convert functions
The operation of PROCscale: PROCscale2
The operation of PROCsca1e2: number formats
The operation of PROCsca1e2: the choice of origin
The operation of PROCscaIe2: the number of graduations
The operation of PROCscale2: values for the ends of the axes
The operation of PROCscale2: the guide to every fifth graduation
The operation of PROCscale2: the smallest and largest values

THE PROCEDURE PROCaxes

The operation of PROCaxes: the origin

THE PROCEDURE PROCgraduate

The operation of PROCgraduate: the graduations
The operation of PROCgraduate: every fifth graduation

THE PROCEDURE PROCmmber

The operation of PROCnumber: the location of the numbers
The operation of PROCnumber: numbering the origin

THE PROCEDURE PROCpoint

The operation of PROCpoint: the length of the bars

THE PROCEDURE PROCgraph

The operation of PROCgraph

THE PROCEDURE PROCbstln

The operation of PROCbstln

THE PROCEDURE PROCnamex

The operation of PROCnamex: positioning the name

THE PROCEDURE PROCnamey

The operation of PROCnamey: positioning the name

THE PROCEDURE PROCchr

The operation of PROCchr: copying the pixels

THE PROCEDURE PROCmessage

The operation of PROCmessage: printing the characters

THE PROCEDURE PROCcurve

The operation of PROCcurve

THE PROCEDURE PROChisto

The operation of PROChisto: the bar position

THE PROCEDURE PROC3Dhisto

The operation of PROC3Dhisto

THE PROCEDURE PROCpie

The operation of PROCpie

The PROCEDURE PROCsector

The operation at PROCsector

THE PROCEDURE PROClabel

The operation of PROClabel

THE TELETEXT PROCEDURE PROCplot
THE TELETEXT PROCEDURE PROCdraw
THE TELETEXT PROCEDURE PROCclg
THE TELETEXT PROCEDURE PROCscale
THE TELETEXT PROCEDURE PROCgraph
THE TELETEXT PROCEDURE PROCaxes
THE TELETEXT PROCEDURE PROCgraduate
THE TELETEXT PROCEDURE PROCnumber
THE TELETEXT PROCEDURE PROCpoint
THE TELETEXT PROCEDURE PROCbstln
THE TELETEXT PROCEDURE PROCnamey
THE TELETEXT PROCEDURE PROCnamex

Appendix 3 The ASCII codes
Index

Next     Top