1. awidthshow
Combine ashow and widthshow spacing adjustments.
1.3. Description
awidthshow paints the characters of string in a manner similar to show, but combines the special effects of ashow and widthshow.
awidthshow adjusts the width of each character shown by adding ax to its x width and ay to its y width, thus modifying the spacing between characters. Furthermore, awidthshow modifies the width of each occurrence of the character char by an additional amount (cx, cy).
The interpretation of char is as described for the widthshow operator.
This operator enables fitting a string of text to a specific width by adjusting all of the spaces between characters by a uniform amount, while independently controlling the width of some specific character, such as the space character.
1.4. Parameters
cx (number)
: Additional x width adjustment for target character
cy (number)
: Additional y width adjustment for target character
char (integer)
: Character code to receive additional adjustment (often space = 32)
ax (number)
: Uniform x width adjustment for all characters
ay (number)
: Uniform y width adjustment for all characters
string (string)
: The text to display
1.5. Examples
1.5.1. Wide Spacing with Extra Wide Word Spacing
/Helvetica findfont 12 scalefont setfont
30 60 moveto (Normal spacing) show
30 46 moveto 6 0 32 0.5 0 (Wide spacing) awidthshow
% All chars get 0.5 units, spaces get additional 6 units1.5.2. Justified Text with Letter Spacing
/fullyJustify { % string targetWidth fullyJustify -
% string targetWidth
1 index stringwidth pop % Get current width
1 index exch sub % Extra space needed
2 index length 1 sub % Number of char spaces
div % Base spacing adjustment
% Apply 60% to all chars, 40% to spaces only
dup 0.6 mul % ax
0 exch % ay ax
3 index % string
% Count spaces
0 exch { dup 32 eq { pop 1 add } { pop } ifelse } forall
% Calculate space adjustment
6 index 4 index sub % Remaining space
1 index div % Space adjustment
0 exch 32 % cy cx char
7 2 roll pop pop % Clean up
awidthshow
} def
(This line will be fully justified) 400 fullyJustify1.6. Errors
invalidaccess : Font or string has restricted access
invalidfont : Current font is not valid
nocurrentpoint : Current point is not defined
rangecheck : Character code or mapping out of bounds
stackunderflow : Fewer than six operands on stack
typecheck : Operands are not of the correct type
1.7. Width Calculation
For each character c in the string:
if c == char: effectiveWidth(c) = characterWidth(c) + (ax, ay) + (cx, cy) else: effectiveWidth(c) = characterWidth(c) + (ax, ay)
The target character receives both the uniform adjustment and the character-specific adjustment.
1.8. Typical Use: Space Character
The space character (ASCII 32) is the most common target:
% Octal notation for space
8#040 % Equals 32
% Hexadecimal notation
16#20 % Equals 32
% Direct decimal
321.9. Advanced Justification
/smartJustify { % string width smartJustify -
% Calculate total adjustment needed
1 index stringwidth pop sub % width - currentWidth
% Count spaces
0 2 index { dup 32 eq { pop 1 add } { pop } ifelse } forall
dup 0 eq {
% No spaces: distribute evenly across all chars
pop
2 index length 1 sub div % adjustment per char-space
0 exch 0 0 0 6 -1 roll awidthshow
} {
% Has spaces: adjust spaces only
div % adjustment per space
0 exch 32 0 0 6 -1 roll awidthshow
} ifelse
} def
(Text to justify) 500 smartJustify1.10. Composition with Other Operators
% awidthshow can be decomposed as:
/myAwidthshow { % cx cy char ax ay string
% This is conceptually what awidthshow does
{
% For each character:
% 1. Check if char matches target
% 2. Add ax, ay to width
% 3. If match, also add cx, cy
% 4. Paint character
% 5. Adjust current point
} forall
} def1.11. Typography Applications
1.11.1. Book-Quality Justification
% Professional justification algorithm
/bookJustify { % string lineWidth bookJustify -
% Prefer adjusting word spacing over letter spacing
% Typical ratio: 80% word spacing, 20% letter spacing
1 index stringwidth pop
1 index exch sub % Space to fill
% Count spaces
0 2 index { dup 32 eq { pop 1 add } { pop } ifelse } forall
dup 0 eq {
% No spaces: use only letter spacing
pop 2 index length 1 sub div
0 exch 0 0 0 6 -1 roll awidthshow
} {
% Has spaces: 80/20 split
1 index exch div % Space per word gap
0.8 mul % 80% to word spacing
dup 5 -1 roll exch sub % Remaining
3 index length 1 sub div % Per letter space
0 exch % ay ax
6 4 roll % Rearrange
32 % Target space char
6 2 roll % Final order
awidthshow
} ifelse
} def