Creatinn Your Own Characters | 81 |
R = LMscemr ‘16 + Wdl”
Fwmal
ESE~i”,P,m m,
Figure 7-9. Character designs for the four card suits.
Like the other Delta commands, it starts with an (ESC) (CHR$(27)). The next character is an asterisk (*), which is CHR$(42), followed by a CHR$(l).
nl is the value we assign to the
n2 is called the attribute byte, for it describes two attributes of the character we have designed: descender data and proportional width information. A byte consists of eight bits. In the attribute byte, the first three (high order) bits are unused, the fourth bit is used for the descender data, and the last four bits are used for proportional widths. We’ll be discussing proportional character widths in detail later in this chapter; for now, we’ll leave it at 11. The descender data was discussed earlier: to use the top seven pins, this bit should be 0; to use the bottom seven pins this bit should be 1. Figure
11.By now you’ve probably seen an easier way to determine the value of the attribute byte. Instead of translating everything to binary, merely assign the descender data a value of 16 (the value of the fourth bit) if you want descenders, or 0 if you don’t want des- cenders. Then just add the descender data to the proportional width. This way, it’s simply a matter of adding two decimal num- bers. (In our case, it’s 0 + 11 = 11.)