[12441] in Athena Bugs
decmips 7.7F: xdvi
daemon@ATHENA.MIT.EDU (Joe Harrington)
Fri Aug 19 18:53:52 1994
Date: Fri, 19 Aug 1994 18:52:20 -0400
From: jh@flolab.mit.edu (Joe Harrington)
To: cfields@MIT.EDU
Cc: bugs@MIT.EDU, yandros@MIT.EDU, kcunning@MIT.EDU, cfyi@MIT.EDU,
bug-sipb@MIT.EDU
In-Reply-To: cfields@MIT.EDU's message of Fri, 19 Aug 1994 17:46:48 +0500 <9408192146.AA01444@perilous.MIT.EDU>
Cc: jh@MIT.EDU
Reply-To: jh@MIT.EDU
(SIPB people, Craig's message to me is below)
Problem found: I have a white-on-black colormap and xdvi's new
antialiasing features are falling flat on their faces. With my setup,
using the G keystroke definitely improved readability, restoring the
old appearance and the functionality of -S. After playing with
-gamma, I was able to find a value that was readable with my color
scheme, and I agree it is better than before.
I wasted two days trying to figure this one out, with no success. Two
consultants were similarly without clues. This indicates to me
serious documentation deficiencies. The man page is incorrect in a
number of places:
- it does not state that -S is ignored by default.
- it does state that selecting higher values for -S gives lighter
fonts, unequivocally and without mention that it only works
for one of two possible rendering methods.
it is also deficient in several ways:
- it describes the new gamma feature *very* far from the other options
that describe ways of changing the appearance of the font.
Since the discussion of -gamma appears after the discussion of
the standard X toolkit options, it is particularly prone to
glossing over (though this isn't what happened in my case).
- it does not state how to get good appearance with white-on-black
display, yet there is a -rv option that gets this type of
display as a short-cut on the command line.
- it does not explain in sufficient detail for an intelligent novice
to understand how it renders fonts and therefore how to go
about tuning its options to get a readable font.
There is also no mention of xdvi's new features (other than that there
might be some) in the release notes.
I also think that the program needs to be modified so that by default
it produces decent, readable output for any color scheme (as readable
as non-antialiased rendering, anyway, you don't have to handle magenta
on fucshia).
>Is it? What is the effect of this loss? Last year on the initial try
>of getting the 600dpi font support into the release, I had no problems
>with printing with the new fonts on a 300dpi printer.
Examined closely, the fonts, and their position on a piece of paper,
are different. Perhaps only a purist could tell, but it's only a few
meg. Its importance for me is much less now that I understand the
xdvi problem.
Thanks for your help.
--jh--
From: cfields@MIT.EDU
Date: Fri, 19 Aug 1994 17:46:48 +0500
To: jh@MIT.EDU, bugs@MIT.EDU
Subject: Re: decmips 7.7F: xdvi
Cc: yandros@MIT.EDU, kcunning@MIT.EDU, cfyi@MIT.EDU
X-Netprob-Ref: 2166
Content-Length: 2565
Hi! You recently reported random problems with xdvi and fonts...
> What were you trying to do?
> Use xdvi to display a DVI file, and read it.
>
> What's wrong:
> The letters are too thin to be read easily. The quality is
> definitely much poorer than the previous release's xdvi.
This is definitely a matter of opinion. I found the quality to be far
better in this release.
> The Athena release 7.7 xdvi (decmips and rsaix, possibly others) has
> two bugs:
>
> 1. the default density (-S) is documented as 20%, but really is 40%.
> This makes the letters come out too thin to be read easily.
Not true. It is in fact 20%.
> 2. the -S option (and the corresponding X resource) don't work to
> change the density setting, forcing you to use the 40% density.
The -S option applies only to the scaling of bitmaps when
anti-aliasing is not used. By default however, anti-aliasing is used,
and therefore the -S option is irrelevant. To turn off anti-aliasing,
use the -nogrey option.
> Since the release 7.7 fonts omit everything below 600dpi, you can't go
> back to using 300dpi/40% with the files in this release.
I really don't think you would want to. Anti-aliasing is the best
thing since sliced bread.
> This renders the 7.7 xdvi useless for displaying readable text.
Not so. From the manual page:
-gamma gamma
(.gamma) Controls the interpolation of colors in the
greyscale anti-aliasing color palette. Default value
is 1.0. For 0 < gamma < 1, the fonts will be lighter
(more like the background), and for gamma > 1, the
fonts will be darker (more like the foreground). Nega-
tive values behave the same way, but use a slightly
different algorithm.
While I'm happy with the default gamma value for black text on a white
background (with my eyes, on my monitor :), it is clearly a matter of
taste. Perhaps those are not your default colors; with my default
colors, I specify a gamma of -2.5. I would suggest you try a value of
1.5 as a start, if you are actually using black on white.
This perhaps could use some treatment in the User Release Notes and
consulting could be better informed about it.
> Also, the loss of fonts below 600 dpi is annoying if you have a 300 or
> 400dpi printer, as many ILG's, departmental clusters, and people on
> resnet do.
Is it? What is the effect of this loss? Last year on the initial try
of getting the 600dpi font support into the release, I had no problems
with printing with the new fonts on a 300dpi printer.
Craig
