Re: FVWM: Vector Buttons

From: Dan Espen <dane_at_mk.telcordia.com>
Date: Thu, 13 Jan 2000 09:16:45 -0500

"Thomas A. Gardiner" <gardiner_at_pas.rochester.edu> writes:
> Hi,
>
> I've got a few quick questions...
>
> 1) Is there a maximum number of allowable points which can be used in a
> vector button? Somewhere between 10 and 20 I get an error saying that it
> was a "bad button style".

The limit is 20 in the 2.2.x series and 32 in the current CVS source.

> 2) More is not necessarily better! I wanted to draw a circle, so I wrote
> a 5-line c-program to pick points on a circle at regularly spaced angular
> increments. This way I get, 3-> triangle, 4-> diamond or square, ... To
> make a circle we want essentially a many sided polygoon. As the number of
> points increases for the same circle radius the button highlighting
> becomes distorted. That is the line becomes distorted. It stands to
> reason that if the input is higher resolution than can be displayed
> nothing should happen; it should look just like the lower resolution
> counterpart.
>
> Without looking at the code I'd guess that this is caused by the
> discretization error of using integers for what should really be a
> floating point number (especially since it must be scaled to the titlebar
> height).

How many pixels high are your title bar?

Even though the vector buttons are defined in units of 100, I'm guessing
that the button itself might be 20x20 pixels.

Given that a vector is not a pixel, but a instead a line segment, I
think your going to find it very difficult to create a circle. With
all the truncation going on, even if there were floating point
calculations involved, its going to be pretty hard to get the
endpoints of the line segments in adjacent pixel locations.

> Any ideas??? The part which bothers me is that if I change the height of
> the titlebar then the button appearance will most likely change so that
> buttons which work good for me may not work well for others.

I think I agree.

> Finally one last question. (Wow, and I thought this was going to be
> short...) Is it possible to set the light and dark colors used for vector
> buttons? If not are they fixed or dependent on the button color.

I don't think so, at least not in the 2.2.x. series.

Vector buttons are nice, but if you really want total control of the button
appearance, pixmaps are the way to go. They don't resize, but you can
control every pixel, and use any color.

--
Dan Espen
444 Hoes Lane  Room RRC 1C-214           E-mail: dane_at_mk.telcordia.com
Piscataway, NJ 08854                     Phone: (732) 699-5570
--
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Received on Thu Jan 13 2000 - 08:19:45 GMT

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