
Creating Your Own Characters | 77 |
letters, and most special characters use only the top seven pins of the printhead. This is also the standard for download characters, so our grid is only seven dots high.
It’s also possible to use the bottom seven pins, just as the “g”, “P“, “q”, and “y” of the standard character sets do. These are called descenders (because the bottom of the character descends below the baseline of the rest of the characters).
One bit in the download character definition command is used to tell Delta whether a character is to be treated as a descen- der or not. We’ll get to the command in due time. For now, if your character uses the top seven dots, write in a zero next to the word “Descender” on the layout grid; if it uses the bottom seven dots, write in a one. In our example, we’ll want the bottom of the heart to line up with the baseline of the other characters, so it will not be a descender. As shown in Figure
n, =
Descender
Width
n, = Descender •16 + Width
Format:
Esc*ln,n2m, m,,
Total
Figure 7-5. We’ve designed a character and decided that it would not be a descen- der. hence the “0” written in.
Rule 2: Dots cannot overlap
As you can see in Figure