HP Pcl 5 Manual

							ENFont Header Format 11-39
Checksum   
The Checksum field is over bytes 64 through the end of the header. 
The checksum should contain a value which, when added to the sum 
of byte 64 through the reserved byte, equals a value which, when 
divided by 256 (modulo 256 arithmetic), results in a remainder of 0. 
For example, if the sum = 10,234 then, 10,234 mod 256 = 250. 
Therefore, the checksum should = 6 (since 250+6 = 256 which 
would produce 0 [mod 256]).
NoteIn the Format 15 Font Header for TrueType Scalable Fonts, this field is 
located at the end of the Segmented Font Data section immediately 
following the descriptor data. See “Segmented Font Data” later in this 
chapter.
Copyright   
This field contains ASCII data and is optional.
NoteIn the Format 15 Font Header for TrueType Scalable Fonts, this field is 
located in the Segmented Font Data section immediately following the 
descriptor data. See “Segmented Font Data” later in this chapter.
Segmented Font Data (Format 15)   
The Segmented Font Data section immediately follows the main body 
of a Format 15 Header for TrueType Scalable Fonts. Each segment 
contains three parts: a Segment Identifier, Segment Size, and Data 
Segment.
The Segmented Font Data section is terminated by the Null Segment. 
(In the deviant case where no Null Segment is encountered prior to 
the end of the font header &emdash; as defined in the Font Header 
command &emdash; the font is invalidated. A font also is invalidated 
in the event that a Null Segment is encountered too soon.)‘‘ffffffff5ffffffe’’ Font indexed in Unicode and is 
compatible only with East Europe 
Latin character sets. Table 11-29  (continued) 
						

							11-40   Soft Font CreationEN
Table 11-30 below shows the structure of the Segmented Font Data 
section.
Segment Identifier (UI)
Each entry in the Segmented Font Data Section has its own unique 
identification number. The following values are defined: Table 11-30 Segmented Font Data 
Byte 15 (MSB)                               8  7                           (LSB) 0
x + 0 First segment, Segment Identifier
x + 2 First segment, Segment Size
x + 4
MFirst segment, Data Segment
M
x + 4
+ 1st
seg size 
Second segment: Segment Identifier, Size, Data 
Segment
M
MM
# – 6 Null Segment Identifier (FFFF - hex)
# – 4 Null Segment Size (0)
# – 2  Reserved  Checksum
x = Font Descriptor Size.
# = Font header length (as defined in Font Header command).
Table 11-31
Value   Mnemonic   Data Segment
17219  CC Character Complement
17232   CP   Copyright
18260   GT  Global TrueType Data
18758 IF Intellifont Face Data
20545   PA  PANOSE Description
22618   XW  XWindows Font Name
65535  Null Segment  
						

							ENFont Header Format 11-41 Data segments with an unrecognized identifier are ignored.
Segment Size (UI)   
For each entry in the Segmented Font Data section, the Segment 
Size indicates the number of bytes in the immediately following Data 
Segment. The size for the Null Segment is 0.
Formats of Data Segments    
AP (Application Support Segment) The definition of this segment is 
reserved.
CC (Character Complement) This field has the same form (i.e., 8 
unsigned bytes) and function as does the Character Complement of 
Format 11 fonts. The Character Complement field should be present 
with type 10 and 11 (unbound) fonts, but has no role to play in type 0, 
1 and 2 (bound) fonts.
CP, copyright This field will consist of ASCII data and is optional.
GI (Global Intellifont Data) Reserved for future use.
GT (Global TrueType Data) This data segment contains first a Table 
Directory, then five or more tables used by the TrueType font scaler. 
Every TrueType font needs to have this segment.
The Table Directory is patterned after the initial segment of the 
TrueType font file as described in True Type Font Files. The Table 
Directory has a 12-byte header and 16 bytes per entry in the Table 
Directory. The Table Directory is organized in alphabetical order by 
the 4-byte table names. For each entry, there is an offset relative to 
the beginning of the soft font’s Global TrueType Data Segment.
The Global TrueType Data for every TrueType font entity must 
contain a head, hhea, hmtx and maxp table.
Another required table is the gdir table. When the font header is 
downloaded, the gdir table should have a size of 0 and an offset of 0. 
The gdir table is then built in RAM to accommodate the maximum 
number of glyphs to be downloaded to the given font — with 2 or 4 
bytes of offset and 2 bytes of length per glyph. This maximum number 
of glyphs is obtained from the numGlyphs field of the maxp table. 
Entries in the gdir table are filled in by the TrueType rasterizer as 
characters are downloaded. 
						

							11-42   Soft Font CreationEN
The optional cvt, fpgm and prep tables, as defined in True Type Font 
Files, typically appear in the Global TrueType Data Segments of 
hinted TrueType soft fonts, but should not appear in unhinted fonts.
IF (Intellifont Face Data) Reserved for future use.
PA (PANOSE Description) This data segment of variable length may 
be used for the purpose of font selection and substitution. Its 
definition continues to evolve. A 10-field (10-byte) version sufficient 
for the description of most Latin fonts appears under the OS/2 table 
inTrue Type Font Files.
PF (PS-Compatible Font Name) Reserved for future use.
XW (x-windows font name) This ASCII field contains standard 
X-Windows font names.
Checksum   
The value of this byte, when added to the sum of all of the bytes from 
byte 64 of the descriptor through the Reserved byte, should equal 0 in 
modulo 256 arithmetic. 
						

							ENFont Header Examples 11-43
Font Header Examples 
Two examples for downloading a Font Header are provided below; 
one for a bitmap font and one for an Intellifont scalable font.
Bitmap Example   
To download a bitmap font header for a portrait HP Roman-8, 10 
pitch, 12 point, upright, medium, Courier font, with an ID number of 
one, send: 
E
C*c1D   (set Font ID to 1)
E
C)s#W   (# = 64 bytes of font descriptor data  
+ x bytes of optional data)
An example of the bitmap header is shown on the following page.
Table 11-32
FIELD NAME VALUE DESCRIPTION
Font Descriptor Size 64 Bytes
Header Format 0 Bitmap Font Format
Font Type   1  Eight Bit
Style MSB  0
Reserved 0
Baseline Position  40
Cell Width  30
Cell Height  53
Orientation 0 Portrait
Spacing 0 Fixed Pitch
Symbol Set  277 8U: Roman-8
Pitch  120  Quarter Dots (30.00 Dots)
Height  200  Quarter Dots (50.00 Dots)
x Height  88  Quarter Dots (22.00 Dots)
Appearance Width  0  Normal 
						

							11-44   Soft Font CreationEN
Intellifont Scalable Example    
To download an Intellifont scalable header for an HP Roman-8, 
upright, medium, CG Times scalable font, with an ID number of one, 
send:
E
C*c1D  (set Font ID to 1)
E
C)s#W  (# = 80 bytes of font descriptor data + x bytes
of Global Intellifont data + x bytes of optional data) Style LSB  0  Upright, Normal Width, Solid 
(0,0,0)
Stroke Weight  0  Medium
Typeface LSB  3  Body Text
Typeface MSB  0  No Font Vendor ID
Serif Style  2  Serif Line
Quality 0 ∅
Placement 0 ∅
Underline Position  -10 ∅
Underline Thickness  3  ∅
Text Height  200 Quarter dots (50.00 Dots)
Text Width  120 Quarter Dots (30.00 Dots)
First Code  33  ∅
Last Code  254 ∅
Pitch Extended  0  ∅
Height Extended  0  ∅
Cap Height 36713  56.02% of Em
Font Number  0  No Font Vendor Number
Font Name Courier
....Copyright Statement .... (optional) }= x bytes added to header data
....Application Support ....(optional) }= x bytes added to header data Table 11-32  (continued) 
						

							ENFont Header Examples 11-45 Table 11-33
FIELD NAME VALUE DESCRIPTION
Descriptor Size 80 Bytes
Header Format 10 Scalable Font Format
Font Type 1 Eight Bit
Style MSB 0
Reserved 0
Baseline Location 5380 Y reference in Design 
Window
Cell Width 0 ..not defined for Intellifont
Cell Height 0 ..not defined for Intellifont
Orientation 0 ..not defined for scalable 
fonts
Spacing 1 Proportional
Symbol Set  277 8U: Roman-8
Pitch 2602 29.63% Em Default HMI
Design Height 2000 250 Points * 8
x-Height 4009 45.65% Em, 68.52% Cap 
Height
Appearance 
Width0Normal
Style LSB 0 Upright, Normal Width, Solid 
(0,0,0)
Stroke Weight 0 Medium or Text Weight
Typeface LSB 5 Times Roman (generic 
design family)
Typeface MSB 16 Agfa
Serif Style 134 Serif, Bracketed (2,6)
Quality 0 ..not defined for scalable 
fonts 
						

							11-46   Soft Font CreationEN
Placement 0 ..not defined for scalable 
fonts
Underline 
Position0 ..not defined for scalable 
fonts
Underline 
Thickness0 ..not defined for scalable 
fonts
Text Height   0  ..not defined for Intellifont
Text Width   4391  Width of En Space
First code   33
Last Code   273  Compound Pieces Present 
(n255)
Pitch Extended   0  ..not defined for scalable 
fonts
Height Extended   0  ..not defined for scalable 
fonts
Cap Height   5851  66.7% Em
Font  Number hex 43 01 69 54  Native,  Agfa,  CG  Times 
(0,C,92500)
Font Name  “CG Times     ”  (16 character ACSII field)
Scale Factor   8782
X Resolution   2540
Y Resolution   2540
Master Underline 
Position  -1747
Master Underline 
Thickness  449
OR Threshold   176
Global Italic 
Angle  0
Global Intellifont 
Data Size  112 Table 11-33  (continued) 
						

							ENFont Header Examples 11-47 ....Global 
Intellifont Data ....}= 112 bytes added to 
header data
....Copyright 
Statement 
(optional) ....}= x bytes added to header 
data
....Application 
Support 
(optional) ....}= x bytes added to header 
data Table 11-33  (continued) 
						

							11-48   Soft Font CreationEN
Character Definitions 
Following the font header, the individual characters must be defined. 
Every PCL character definition contains a character descriptor and a 
body of character data. The character definition always consists of 
one or more character data blocks. Each character data block begins 
with its own header. The character data block header always has a 
size of 2 bytes.
The first data block of a character definition must always have a 
character descriptor immediately after its 2-byte header.
Character descriptor/data is downloaded using the Character 
Definition command preceding every character (see Character 
Definition Command).
NotesA unique character code, using the Character Code command, must 
be designated prior to the download of a character descriptor and 
data. If the font being downloaded already contains a character with 
this code, the existing character is deleted during the download of the 
character descriptor and data.
Unless otherwise specified, inappropriate values in a character 
descriptor field invalidates the character download process; a 
character is not created, and the associated descriptor and data 
are discarded.
An undefined printable character is one which is in the printable 
range of the font type but has no defined pattern. Attempts to print 
an undefined printable character from a font result in the execution 
of a Space control code.
Character descriptor fields identified as “reserved” should be set to 
zero.
If the total byte count of the character descriptor and data exceeds 
32767 bytes, then the remaining data must be sent using the 
continuation descriptor.