GRAPHICS SOFTWARE AND LANGUAGE STATEMENTS

In case you haven't already guessed, how easily we can draw things on the screen is greatly affected by the types of program instructions the manufacturers provide for manipulating screen elements. Today most graphics instructions are part of the popular BASIC language. BASIC is a very simple computer language to learn and there are many good books available to learn it from.^*

The language statement provided for controlling the screen can be as elementary as SET x, y, which on the TRS-80 turns a screen element located at x,y ON (white), or COLOR = n, which on the Apple II sets the color to one of sixteen colors (n = 0-15). On the other hand, the statements can be extremely sophisticated and powerful like the Apple's HPLOT x1, y1 TO x2, y2 statement, which draws a vector line from x1, y1 to x2, y2, or the Bally's BOX x, y, a, b statement, which places a box of any dimension at any location on the screen, or the Apple's ROT = statement, which rotates a predefined shape on the screen through one of sixty-four rotations.