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Chapter 4. Record Formats<br />
Character Definition Record (CDR)<br />
Byte Position Bytes Field Name Description<br />
7 1 Segment Count A binary number that specifies the number of 16-bit segments<br />
required to define one horizontal row of the character bitmap. The<br />
final segment does not have to be completely used. The “Final<br />
segment width” bits in position 8 define how many bits in the final<br />
segment are used. All binary zeroes (hex 00) in position 7 indicate<br />
a null character with zero width.<br />
8 1 Options The bits in position 8 define options available for this character. Bit<br />
0 is the high order bit (hex 80) and bit 7 is the low order bit (hex<br />
01). Bit assignments are as follows.<br />
Bit 0 (hex 80 bit)=Equivalent bit (no bitmap data).<br />
Bit 1 (hex 40 bit)=Continuation bit.<br />
Bits 2-7 (hex 3F bits)=Final segment width.<br />
If bit 0 is set to 1, the bitmap for this character is equivalent to that<br />
for the character specified in byte position 6 and the bitmap is not<br />
repeated in this CDR. If bit 1 is set to 1, the pattern for this<br />
character is continued in the next CDR.<br />
Bits 2 through 7 contain a binary number in the range of 0 through<br />
63. When the value is 1 through 16, it represents the number of<br />
bits in the final 16-bit segment that are to be used. When the value<br />
is 17 through 63, the entire final segment is used and additional<br />
zero bits are created to fill out the additional bit positions. When<br />
the value is 0, the entire final segment is used and 48 additional<br />
zero bits are created to make a final segment containing 64 bits.<br />
For example, a hex 45 in position 8 indicates that the continuation<br />
bit is set and 5 bits of the final segment are used.<br />
9-n n Bitmap Pattern The bitmap pattern for the character defined by this CDR. The<br />
pattern data consists of m rows, each containing s 16-bit<br />
segments, where m is the font height (row count) defined in bytes<br />
5-6 of the FDR, and s is the segment count defined in byte 7 of the<br />
CDR.<br />
Each row must be padded to the right with binary zeroes.<br />
If the equivalent bit in byte position 8 is set, this field can contain<br />
font or super font identifiers. Refer to the description for the<br />
Equivalent Character Identifier field (byte position 6).<br />
If the character pattern will not fit in a block, a continuation CDR<br />
must be used. An integral number of rows must be used in each<br />
CDR record.<br />
4 - 24 IJPDS Formats
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