Path: utzoo!attcan!uunet!nih-csl!lhc!ncifcrf!fcs260c2!toms
From: toms@fcs260c2.ncifcrf.gov (Tom Schneider)
Newsgroups: comp.lang.postscript
Subject: Re: Variable characters
Keywords: font, character size
Message-ID: <1936@fcs280s.ncifcrf.gov>
Date: 6 Nov 90 18:18:08 GMT
References: <1902@fcs280s.ncifcrf.gov> <21131@well.sf.ca.us>
Sender: news@ncifcrf.gov
Organization: NCI Supercomputer Facility, Frederick, MD
Lines: 163

In article <21131@well.sf.ca.us> shiva@well.sf.ca.us (Kenneth Porter) writes:
>
>When I need to get characters to fit a pre-defined space (such
>as is the case on my business card), I always calculate the
>point size, sometimes with x and y computed independently. The
>x size can be calculated by using stringwidth after setting the
>font at 1 point.  The y size can be calculated by iterating
>over the string and reading the metric info for each character.
>If you need to set x and y scale independently, use makefont
>instead of scalefont and provide a scale matrix.
> 
>This allows me to substitute fonts ad hoc without digging out
>my calculator to recalculate all of the sizes.  Just let the PS
>interpreter do the grunt work.
> 
>Ken (shiva@well.sf.ca.us)

Without an exact program, it is next to impossible to replicate what you do.  I
have ALMOST solved my problem, but not quite!  To prove that I am able to
control the character sizes, I decided to make the characters appear inside
boxes.  Unfortunately, they don't match the boxes exactly, and I don't know
why.  Following is my latest attempt.  Can you tell me why the characters STILL
don't fit the boxes exactly?  What is the problem with this code, and how do I
fix it?  (I print this on a LaserWriter ntxII.  NeWS 1.0 fails utterly.)

  Tom Schneider
  National Cancer Institute
  Laboratory of Mathematical Biology
  Frederick, Maryland  21702-1201
  toms@ncifcrf.gov

- snip - snip - snip - snip - snip - snip - snip - snip - snip - snip

(version = 2.31 of charbox.ps TDS 1990 November 6 \n) dup print
% Show the 4 characters ACGT surrounded by boxes that exactly match
% the characters.  Unfortunately, this version of the program ALMOST
% works.  The C and G characters are displaced downward by about 1mm
% relative to A and T.  The reason for this is unknown, can you figure
% it out?
%  Tom Schneider
%  National Cancer Institute
%  Laboratory of Mathematical Biology
%  Frederick, Maryland  21702-1201
%  toms@ncifcrf.gov

/cmfactor {72 2.54 div} def % defines points -> centimeters conversion
/cm {cmfactor mul} def % defines centimeters

% Show the version number on the page
initgraphics
erasepage
gsave
/Helvetica findfont 14 scalefont setfont
1 cm 25 cm moveto show
grestore

1 setlinewidth % define the width of the dashed lines
1 setflat % define the accurcy with which curved path segments
          % are to be rendered on the raster output device.
          % Even setting this to 0.01 makes no difference!

% Set up the font for the graphics
/fontsize 30 def
/Helvetica-Bold findfont fontsize scalefont setfont

/charparams { % char charparams => uy ux ly lx
% takes a single character and returns the coordinates that (supposedly)
% defines the outer bounds of where the ink goes
  gsave
    newpath
    0 0 moveto
    % take the character off the stack and use it here:
    true charpath 
    flattenpath 
    pathbbox % compute bounding box of 1 pt. char => lx ly ux uy
    % the path is here, but toss it away ...
  grestore
  /uy exch def
  /ux exch def
  /ly exch def
  /lx exch def
% print the parameters to the user:
(lx) lx
(ly) ly
(ux) ux
(uy) uy
pstack
clear % clean up the stack, having printed all that
} bind def

/box { % xsize ysize box -
% draw a dashed box of xsize by ysize
  /ysize exch def % the x size of the box
  /xsize exch def % the y size of the box
  gsave
    newpath
    0 0 moveto
    xsize 0 lineto
    xsize ysize lineto
    0 ysize lineto
    0 0 lineto
%
    [3] 0 setdash
    stroke
  grestore
} bind def

/boxshow { % xsize ysize char boxshow
% show the character with a box around it
gsave
  /tc exch def % define the character
  /ysize exch def % the x size of the character
  /xsize exch def % the y size of the character

  xsize ysize box

  tc charparams

  ysize % desired size of character in points
  uy ly sub % height of character in points
  div % factor by which to scale up the character
  /ymulfactor exch def

  xsize % desired size of character in points
  ux lx sub % height of character in points
  div % factor by which to scale up the character
  /xmulfactor exch def

  /xmove xmulfactor lx mul neg def
  /ymove ymulfactor ly mul neg def

  newpath
  xmove ymove moveto
  xmulfactor ymulfactor scale
  tc show
grestore
} def

gsave

    2 cm 2 cm translate

    /size 22 def

    3 cm 0 translate
    0 0 moveto
    1 cm size cm (A) boxshow

    3 cm 0 translate
    0 0 moveto
    1 cm size cm (C) boxshow

    3 cm 0 translate
    0 0 moveto
    1 cm size cm (G) boxshow

    3 cm 0 translate
    0 0 moveto
    1 cm size cm (T) boxshow

grestore

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