Vector fonts for IBM GL (AIX 3.1 on RS/6000)

Vector fonts for IBM GL (AIX 3.1 on RS/6000)

Post by blu.. » Wed, 07 Nov 1990 14:48:47



Hello GL users,

As far as I remember Silicon Graphics's GL included vector fonts.  Somehow
this feature seems to not apear in IBM's GL (which is supposed to be
compatible).  Is it realy so?  Can I somehow add this functionality?

As a long shot, is it possible to mix XDPS with GL ?!?

Any pointers are welcome ...

Thanks
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Vector fonts for IBM GL (AIX 3.1 on RS/6000)

Post by gravishan.. » Thu, 08 Nov 1990 03:51:50



> Hello GL users,

> As far as I remember Silicon Graphics's GL included vector fonts.  Somehow
> this feature seems to not apear in IBM's GL (which is supposed to be
> compatible).  Is it realy so?  Can I somehow add this functionality?

> As a long shot, is it possible to mix XDPS with GL ?!?

> Any pointers are welcome ...

> Thanks
> --
> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=


> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

Hi

I have struggled enough with this trying to port some stuff from Iris to
RS/6000 that I feel I can point you to some things. Silicon Graphics GL
provides only a single (not so good looking) font by default. (Font 0). You are
supposed to define your own fonts using defrasterfont and use them. However,
IRIX also provides a font manager, which has a lot more fonts that one can use.
Apparently IBM didn't license the font manager, so you cannot get access to
the extra font set (Postscript fonts) in the RS/6000 the way you do on Iris.

With the help of our tech. rep. we traced the connection to loadXfont man
pages, which basically gives access to all X fonts from a GL based program. You
have to look in info under defrasterfont and trace your way into loadXfont and
eventually to a sample program xfont.c. If you follow instructions there, you
must theoretically have access to all the X fonts. Here is what I found out and
I am still working on it:

        1. xfont.c seems to have errors. The call to XListFonts uses simply
"helv" and it is wrong. It should be "helv*".

        2. Assigning a font number 433, as in the example xfont.c didn't work
for me. I had to choose a number below 255. Though the man pages (In my Iris)
say that the font call parameter is Integer*4 (For Fortran Call) and short for
C call (Which is in conflict anyway), I don't understand why a number above 255
does not work for me. If you use 433, you see no errors, but only the default
font is shown.

        3. After all these, the fonts don't show up properly in the window.
They look messed up for any Helvetica font I try to use. If I try to use

signs.

If you try and have success, please let me know what I am doing wrong. I posted
these once before, but apparantley it never made it.

Ravi

 
 
 

Vector fonts for IBM GL (AIX 3.1 on RS/6000)

Post by Kurt Akel » Fri, 09 Nov 1990 02:21:10


|> Hello GL users,
|>
|> As far as I remember Silicon Graphics's GL included vector fonts.  Somehow
|> this feature seems to not apear in IBM's GL (which is supposed to be
|> compatible).  Is it realy so?  Can I somehow add this functionality?
|>
|> As a long shot, is it possible to mix XDPS with GL ?!?
|>
|> Any pointers are welcome ...

Vector fonts have not been included in SGI GL releases for a long time,
perhaps as long as 4D machines have been shipped.  The IBM version of the
GL is comparable to the 3.2 release of the SGI GL, which certainly didn't
include vector fonts.

It is easy to draw vector fonts using the GL, however.  Be forewarned,
though, that using the relative move and draw commands, which is a
traditional and seemingly good technique, is not a good idea.  Rather,
each vector character should be drawn using its own matrix, from a
representation using absolute coordinates.  The required matrix push,
translate, scale, and pop do not add up to significant overhead on
modern GL systems, and besides, if your character scale was not equal
to the scale of the image being overdrawn, all but the translate were
required anyway.

Many recently-added GL features, such as local lighting computations,
do not work well with relative drawing commands.  Both these drawing
commands and the related concept of current graphics position are
obsolete, and will eventually be removed from the GL.

-- kurt