Table of Contents

• 1. definefont
  • 1.1. Syntax
  • 1.2. Stack Effects
  • 1.3. Description
  • 1.4. Parameters
  • 1.5. Returns
  • 1.6. Examples
    • 1.6.1. Registering a Simple Type 3 Font
    • 1.6.2. Re-encoding an Existing Font
    • 1.6.3. Registering with VM Allocation
  • 1.7. Errors
  • 1.8. Font Dictionary Requirements
    • 1.8.1. Required Entries for All Fonts
    • 1.8.2. Type 1 Font Specific
    • 1.8.3. Type 3 Font Specific
    • 1.8.4. Composite Font Specific
  • 1.9. Font Directory
  • 1.10. VM Allocation Behavior
  • 1.11. Font Registration Process
  • 1.12. See Also

1. definefont

Register font in font directory.

1.1. Syntax

key font definefont → font

1.2. Stack Effects

Before:

key font

After:

font

1.3. Description

definefont registers font as a font dictionary associated with key (usually a name). definefont first checks that font is a well-formed font dictionary—in other words, contains all required key-value pairs. It inserts an additional entry whose key is FID and whose value is an object of type fontID. The dictionary must be large enough to accommodate this additional entry. It makes the dictionary’s access read-only. Finally, it associates key with font in the font directory.

In Level 2, it is permissible to associate a font dictionary with more than one key. If font has already been registered, definefont does not alter it in any way.

If font is a composite font, definefont also inserts the entries MIDVector and CurMID, and adds entries PrefEnc, EscChar, ShiftIn, and ShiftOut if they are required and are not already present. All the descendant fonts must have been registered by definefont previously.

Subsequent invocation of findfont with key will return font. Font registration is subject to the normal semantics of VM. In particular, the lifetime of the definition depends on the VM allocation mode at the time definefont is executed. A local definition can be undone by a subsequent restore.

definefont is actually a special case of defineresource operating on the Font category.

1.4. Parameters

key (name or string) : The name under which to register the font

font (dictionary) : The font dictionary to register (must be well-formed)

1.5. Returns

font (dictionary) : The same font dictionary, now registered and with FID added

1.6. Examples

1.6.1. Registering a Simple Type 3 Font

/MyFont 10 dict begin
  /FontType 3 def
  /FontMatrix [0.001 0 0 0.001 0 0] def
  /FontBBox [0 0 1000 1000] def
  /Encoding 256 array def
  0 1 255 { Encoding exch /.notdef put } for

  /BuildChar {
    % Custom character building code
    1000 0 setcharwidth
    newpath
    100 100 800 800 rectfill
  } def

  currentdict
end
/MyFont exch definefont pop

1.6.2. Re-encoding an Existing Font

% Get Helvetica and create custom encoding
/Helvetica findfont
dup length dict begin
  { 1 index /FID ne {def} {pop pop} ifelse } forall

  % Create new encoding array
  /Encoding 256 array def
  0 1 255 { Encoding exch /.notdef put } for

  % Define specific characters
  Encoding 65 /A put
  Encoding 66 /B put
  % ... more encodings

  currentdict
end
/Helvetica-Custom exch definefont pop

1.6.3. Registering with VM Allocation

% Define in global VM for persistence
true setglobal
/MyGlobalFont findfont 12 scalefont
/MyGlobalFont-12 exch definefont pop
false setglobal

% Font persists across jobs

1.7. Errors

limitcheck : Font dictionary is too large for implementation

rangecheck : Font dictionary values out of acceptable range

dictfull : Font dictionary doesn’t have room for FID entry

invalidfont : Font dictionary is not well-formed or missing required entries

stackunderflow : Fewer than two operands on stack

typecheck : key is not name/string or font is not dictionary

invalidaccess : Font dictionary access violations

1.8. Font Dictionary Requirements

1.8.1. Required Entries for All Fonts

• FontType - Integer (1, 3, 0 for composite)

• FontMatrix - 6-element array

• FontBBox - 4-element array [llx lly urx ury]

• Encoding - 256-element array (for base fonts)

1.8.2. Type 1 Font Specific

• CharStrings - Dictionary of character descriptions

• PaintType - 0 (filled) or 2 (stroked)

• Private - Dictionary of private font data

1.8.3. Type 3 Font Specific

• BuildChar or BuildGlyph - Character construction procedure

1.8.4. Composite Font Specific

• FMapType - Font mapping type

• FDepVector - Array of descendant fonts

1.9. Font Directory

Fonts are stored in FontDirectory:

% Access font directory
FontDirectory /Helvetica known {
  (Helvetica is defined) =
} if

% In Level 2, check global fonts too
GlobalFontDirectory /MyFont known {
  (MyFont in global VM) =
} if

1.10. VM Allocation Behavior

Local VM (false setglobal): - Font definition removed by restore - Visible only to current job - Descendant composite fonts copied

Global VM (true setglobal): - Font definition persists across jobs - Visible to all contexts - Typically used for Type 1 fonts loaded from disk

1.11. Font Registration Process

definefont performs these steps:

1. Validates font dictionary structure

2. Checks required entries exist and are correct type

3. Adds FID (font identifier) entry

4. Makes dictionary read-only

5. Stores in FontDirectory or GlobalFontDirectory

6. For composite fonts, adds additional entries

1.12. See Also

• findfont - Obtain font dictionary by name

• undefinefont - Remove font from font directory

• scalefont - Scale font by uniform factor

• makefont - Transform font by matrix

• setfont - Establish current font