1.The computer is prevented from adding any extra characters by the WIDTH statement (line 100).

2.The line spacing is changed to 8/72 of an inch-the height of the dot patterns used in the program (line 110).

3.The program goes through the graphics commands the required number of times (lines 120 and 170).

4.A new graphics command is used for each line printed (lines 130- 160). This part of the program is similar to the last example, but two columns are printed each time through the loop making a total of 100.

5.The last important thing to do is to reset the printer to its default settings, including the normal line spacing (line 180).

Notice that the graphics command (ESC K) can be in effect for only one print line. To print more than one line of graphics, the graphics command must be issued before each line.

Density Varieties

Although all the examples so far in this chapter have been in the singledensity graphics mode, there are six other eight-pin densities and two that use all nine pins. Nine-pin graphics is not necessary for most uses, but you can find the command (ESC ^) in the Command Summary (Appendix A).

The four most common eight-pin modes are ESC K, ESC L, ESC Y, and ESC Z. There is also a general-purpose command for any of the eight-pin graphics modes: ESC *. This command is used in the same way as the individual commands, except that before nl and n2 you must send the code for the graphics mode required. The different modes are summarized in Table 6-1.

The following example shows how to use the ESC * command to reserve 40 columns for single-density graphics. This uses mode number 0 from the table to achieve exactly the same effect as the first example using ESC K.

LPRINT CHR$(27);"*";CHR$(0);CHR$(40);CHR$(0);

6.8

Introduction to Dot Graphics