ShareWare OnLine 2/ShareWare OnLine Volume 2 (CMS Software)(1993).iso/cad/acadfont.zip/MKFONT.ZIP/MAKEFONT.DOC

Text File | 1992-02-01 | 8KB | 140 lines

From CADENCE Magazine May, 1991

Head: Make Your Own

Sub: Create Fonts with  MAKEFONT.LSP

by Brad Halls
MAKEFONT.LSP  (Listing 1) is an AutoLISP program designed to  aid
in  creating  and customizing fonts for AutoCAD. The  program  is
designed  so  that anyone can customize fonts  without  having  a
thorough  knowledge  of AutoCAD shape  files.  MAKEFONT.LSP  also
handles  the frustrating process of generating the  actual  shape
code  from  the  creator's shoulders. To  do  this,  MAKEFONT.LSP
prompts the user through the description of a character and keeps
track  of pen movements, drawing modes, and the number  of  bytes
needed  to describe the character in AutoCAD's SHP  file  format.
There  are  five  steps needed to run the program  and  create  a
custom font.

CREATING THE DRAWING
(Note: see included makefont.dxf.)
Grid  size  is the first thing to consider when  creating  a  new
font.  I found that a 50 x 50 grid works well, but the base  size
is really arbitrary. In general, the more detailed the font,  the
more accuracy needed to define it and hence the larger the  grid.
Once  the  size is decided, the drawing limits should be  set  to
match the grid.
Next, the units and snap need to be set so that the program  will
write  integer values to the SHP file. Call up the Units  command
and set the units to "decimal" (option 2), with zero places after
the decimal point. The snap should be on and set to 1. The screen
coordinates should be on and displaying integer values.
It  is  a good idea to set up a view slightly  larger  than  your
grid, so the entire character can still be seen if you decide  to
go  outside the limits (zoom .8x should do it). Now, turn on  the
grid, save the view, and end the drawing.

DESIGNING THE CHARACTER SET
Now  that the drawing grid is set up, you should be ready to  lay
out  individual  characters in the font.  Fortunately,  it  isn't
necessary  to  complete  the entire character  set  in  order  to
compile  the  font,  so it is possible to start  with  the  less-
complicated characters and compile them first.
Since  the program works by digitizing each character  to  create
the SHP file, no true arcs are allowed. You can, however, achieve
pretty good results by using a series of short line segments as I
have  shown  here  for the number 2 (Figure 1).  Of  course,  the
characters  don't  need  to  be drawn  out  at  all_they  can  be
digitized  from scratch. This, however, would be more  difficult.
Remember, the more vectors (points) it takes to describe a  font,
the  more  time  will be needed to display it, so  don't  get  to
detailed  unless you are prepared to wait for many of long,  slow
regens.
When  creating  a character set, it is also a good idea  to  take
advantage  of AutoCAD's subshape feature whenever  possible.  Any
character can be used as a subshape for another character, so  it
is  possible  to  save time and file  space  by  using  subshapes
creatively. One example is using the existing digits 0 through  9
as  subshapes  to create the fractional characters  1/16  through
15/16. The keys that the fractions are assigned to are up to you.
The lowercase keys "qwerty" and "asdfg" work well if you  usually
use caps on your drawings.
Another  advantage of creating a custom font is  that  frequently
used  characters  that are are not standard ASCII,  such  as  the
"plate"  and "center line" symbols used by many AE firms, can  be
easily  added  and  assigned to any  key  available.  After  each
character  is completed to your satisfaction, make a block of  it
to be digitized later.

BEGINNING A PROTOTYPE
FONT FILE
Before  a  font can be compiled, a special shape  number  0  that
contains  information  about  the  font  name,  size,  and   text
orientation must be added. This should be the first entry in  the
SHP file, followed by the codes for a space (ASCII 32) and a line
feed  (ASCII  10). For a 50 x 50 grid, the  first  three  entries
should look something like this: (see accompanying template.shp).
Copy this file and rename it  to whatever  you want to call your
font, then adjust the sizes accordingly.

*0,4,fontname
50,0,2,0
*32,5,space
2,8,(50,0),0
*10,5,line_feed
2,8,(0,-75),0

These  lines  of code (or something similar) need to  be  written
into a file with an SHP extension and placed in the AutoCAD  root
directory  so that the character descriptions  from  MAKEFONT.LSP
can be appended to it later.


DEFINING A CHARACTER
Now  you  are ready to begin digitizing the characters  you  have
made and writing their descriptions to the SHP file. Call up  the
MAKEFONT.DWG  and  insert  the first character  block.  Load  the
MAKEFONT.LSP  program  and follow the  instructions  from  there.
Figure 1 shows the description process for a number 2. Start  out
by picking (0,0) for the origin and then typing "U" (for pen up).
Pick  point  number 2, and type "S" to start the  continuous  pen
down  (or  CPD)  mode.  Now  pick  continuous  points  along  the
character path through point number 3. Type "E" to exit CPD  mode
and  "U"  to raise the pen. Pick point number 4 and type  "D"  to
lower  the pen, then pick point number 5. Type "U" and  pick  the
point  (50,50). The character is now complete, so type a  "Q"  to
quit  the  description process. Note that the last point  of  one
character  is  the insertion point for the next, so  if  the  "2"
would  have  used  the  entire 50 x 50  limits,  the  last  point
digitized would have been about (60,0) instead of (50,0).
The program will now ask if you want to write the description  to
a file. Respond with a "y," and MAKEFONT.LSP will prompt you  for
the  name  of  the  SHP file created in step  3.  Type  the  name
(without  the SHP extension). Next you will be prompted  for  the
ASCII  code and a short description of your character. The  ASCII
codes  for  the keyboard are listed on page 387  of  the  AutoCAD
manual. The description (not the one provided by the program  but
by  you)  should  be short and contain  no  spaces  or  uppercase
letters. Autodesk uses "uca" for an uppercase "A," but  something
like "upper_case_a" will also work and may be more readable.

COMPILING AND TESTING THE FONT
After  the character is finished, end the MAKEFONT.DWG  and  type
"7"  at the AutoCAD main menu to compile your font. Now  go  back
into  that drawing or start a new one and create a  style  (test,
for  example)  that utilizes the new font. If all goes  well,  it
should  be possible to create a fairly large character set  in  a
short  amount  of time. Compilation errors for  shape  files  are
sometimes  difficult to find, so be patient and consult  appendix
B.7  of  the AutoCAD Reference Manual  for  further  information.
Compile  and test your font often as new letters are  created  so
that you will have a good idea of where to find any problems that
may arise. One hint is to watch for trailing blanks at the end of
lines  or a missing return at the end of the SHP file. Keep  your
favorite word processor handy for debugging and have fun with it.
Good Luck! @

Brad  Halls  is  a  CAD  designer  and  programmer  for  Ruby   &
Associates, P.C. in Southfield, Michigan.