bggen(l) bggen(l)
NAME
bggen - generates colored backgrounds on X11 displays
SYNTAX
bggen [-w width] [-s size] [-b bits] r1 g1 b1 [r2 g2 b2
... rn gn bn]
DESCRIPTION
bggen is a program that generates a width-pixel wide by
size-pixels high vertical stripe. The top of the stripe
is in color (r1,g1,b1), and the bottom of the stripe is in
color (rn,gn,bn). Intermediate colors are interpolated
between these colors. If you specify more than 2 colors,
the stripe passes through all the specified colors, in the
order specified.
The '-b' option specifies the number of significant bits
in the (output) color specifications. It must range
between 1 and 8, inclusive. Use values less than 8 (the
default) to limit color use by increasing the color granu-
larity.
Values for 'r', 'g', and 'b' should range between 0 and
255, inclusive. 0 means 'off', and 255 means 'fully on'.
bggen doesn't actually affect your background directly.
bggen merely generates a small PPM (Portable Pixmap For-
mat) datafile that XV can read and display.
To use bggen, you should pipe its output into an XV com-
mand, such as: "xv -root -quit -slow24"
The default 'size' is 1024 pixels, which should be as tall
as your display. If your display is taller than that, you
should specify its actual height, otherwise you will get a
bizarre repeating effect, that you probably didn't want.
Note: If you specify small values of '-s', you can get
some neat effects.
The '-w' argument has been added to improve the perfor-
mance of various stippling algorithms (as in XV). More
information to work with, and such. Try using '-w 16' on
these command lines to see what is meant.
TRY THESE
Light Blue to Dark Blue
bggen 100 100 255 50 50 150 | xv -ro -q -slow24 -
RGB Rainbow
bggen 0 0 255 0 255 0 255 0 0 | xv -ro -q -slow24 -
Green Cylinders
bggen 0 0 0 0 255 0 0 0 0 -s 128 | xv -ro -q -slow24 -
Blue to Magenta
bggen 0 0 255 200 0 100 | xv -ro -q -slow24 -
Full Rainbow
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bggen(l) bggen(l)
bggen 0 0 255 0 255 255 0 255 0 255 255 0 255 0 0 | xv -ro -q -slow24 -
Repeating Rainbow
bggen 0 0 255 0 255 255 0 255 0 255 255 0 255 0 0
255 0 255 0 0 255 -s 256 | xv -ro -q -slow24 -
It'd probably be nice if the program used some X calls to
determine screen size. It'd also probably be nice if the
program could take colors by 'name', and also by hexadeci-
mal value.
AUTHOR
John Bradley - bradley@cis.upenn.edu
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