labox and drift

[ag]

Hello,
I am working on a gantt type of chart, using a textbox, continuos form, and
labox text, as well as some vertical lines to demarc hours and half hours.
On the far left everything is fine with with the labox text string, but as
the bars and spaces moves towards the right, I get what I am calling
"drift", whereby a time bar that starts at 10pm looks like 10:10 and goes
to 11:10 instead of 11pm.
I can add or remove text to compensate, but if anyone can tell me a simple
solution, or what I'm missing about using labox font and this type of
scenario, I'm all ears.
Thanks,
Al

 

[John Nurick]

Hi Al,

The first thing to exclude, I think, is that it's the result of
"rounding errors" (to speak loosely) stemming from the relationships
between font size, printer resolution, screen resolution, twips or
points and millimetres.

Try changing your setup (the LaBox font size, I guess) so that the width
of your "unit" is both a whole number of twips and a whole number of
"dots" at your printer's resolution (never mind whether the rest of the
layout looks good). If that fixes the "drift", continue experimenting
until you get something you can live with.

Also check that the fonts the printer is using are the ones you think
(the font substitution settings in the printer driver).

 

[ag]

Also check that the fonts the printer is using are the ones you think
(the font substitution settings in the printer driver).

Hi John,
Thanks for the info. I guess one thing that makes this a little more
frustrating than usual may be because labox is rendered in "em" units
rather than px. From what I've read, px units render from device to
device more consistently, whereas em units are more device specific.
Given this and your reply, do you think I might be better to experiment
with a more "generic" printer, rather than trying to find the right font
width? I mention this because the combinations and permutations with
labox could be endless ie pppp or totototo or qwqwqwqw.
Al

 

[John Nurick]

In real typography, an em is usually a unit of width equal to the point
size of the type. I.e. if you're using 12 pt type, an em is 12 points
(240 twips) wide.

I don't think pixels should come into it, but if you're working in
metric units or decimal inches you do need to watch out for rounding
errors or creep associated with conversion to points and twips.