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Chapter 1. Overview<br />
Fonts<br />
Negative Y offset for f<br />
1 - 12 IJPDS Formats<br />
Category II fonts allow the printing of a line at any angle as shown in<br />
Figure 1.12. As seen for the character A, the characters must be defined<br />
at an angle in their bounding boxes. The character escapement values<br />
are then used to produce angle printing.<br />
Figure 1.12 Vertical, right-to-left, and angle printing<br />
Vertical printing<br />
X escapement = 0<br />
Y escapement = n<br />
Character offsets let you design fonts using a baseline method. This<br />
method, illustrated in Figure 1.12, uses a negative Y offset for each<br />
character to place the character above the cursor position in the page<br />
buffer. Therefore, a baseline for all characters can be maintained.<br />
As shown in the illustration, the baseline method is useful when there is<br />
the possibility of changing font sizes in a line. The f character in Figure<br />
1.13 is larger than the other characters but maintains the same baseline.<br />
Figure 1.13 Baseline font design<br />
Regular and Super Fonts<br />
Right-to-left printing<br />
X escapement = negative n<br />
Y escapement = 0<br />
Angle printing<br />
Baseline<br />
X character escapement<br />
Y character escapement<br />
Both category I and category II fonts can be regular or super. A regular<br />
font is a single-byte font that allows each character to be accessed with a<br />
1-byte code. For example, a 1-byte code of hexadecimal 41 is used to<br />
access the text character A in an ASCII text font. A super font is a doublebyte<br />
font that allows each character to be accessed with a 2-byte code.<br />
Super fonts are required for languages with more than 256 characters in a<br />
font.<br />
The number of regular and super fonts, including both category I and<br />
category II, in an IJPDS job file cannot exceed 255.