bggen - generates colored backgrounds on X11 displays
[-d display] [-g geometry] [-G rptgeom] [-r rot] [-a] [-w width]
[-h height] [-b bits] <color-spec> [<color-spec> ...]
is a program that generates a rectangular 24-bit image, with a
smooth vertical gradient between the listed colors. (If you only specify one
color, the image will be a single solid color.) The top of the image will be
in color (r1,g1,b1), and the bottom of the image will be in color (rn,gn,bn).
Intermediate positions in the image are interpolated between these colors. If
you specify more than 2 colors, the gradient passes through all the specified
colors, in the order specified.
The '-d' option lets you specify what display to connect to. bggen
connects to the display to find out the size of the screen (and hence, the
default size for the generated image).
The '-g' option lets you control the size of the image, as a standard X geometry
specification. (ie, something like "512x348")
The '-G' option lets you control the tile size, as a standard X geometry
specification. (ie, something like "32x32") Normally, (if you don't
give a -G option), the gradient fills the entire image. If you specify a -G
option, the gradient will fill a portion of the image, and that portion will
be 'center-tiled' to fill the rest of the image.
The '-r' option lets you rotate the gradient counter-clockwise by the specified
number of degrees.
The '-a' option lets you force bggen to generate an image in PPM 'Ascii' format,
rather than in PPM 'raw' format.
The '-w' and '-h' options also let you set the size of the image. They are
provided only for backward compatibility.
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 granularity. Since
XV can do this sort of thing better, this is of dubious value.
A <color-spec> can be three integers separated by spaces, forming an R,G,B
triple ("0 255 0"). The values should be between 0 and 255.
A <color-spec> can also be a standard X color specification by name
("green") or value ("#00ff00"). This is decidedly easier,
and the 'three integer' method remains mainly for backward compatibility. One
note: the '#' character is treated specially by many shells, and should
probably be protected by putting a '\' character in front of it, or wrapping
the entire value with a pair of single-quotes.
doesn't actually affect your background directly. bggen
merely generates a PPM (Portable Pixmap Format) datafile and dumps it to
'stdout'. It's up to some other program (such as XV) to read this file and
To use bggen
, you should pipe its output into an XV command, such as:
"xv -root -quit -"
Light Blue to Dark Blue
bggen 100 100 255 0 0 100 | xv -root -quit -
bggen red green blue | xv -root -quit -
bggen black green black -h 128 | xv -root -quit -
Blue to Magenta
bggen blue magenta | xv -root -quit -
bggen black red yellow green blue purple black | xv -root -quit -
bggen red yellow green blue purple red -h 256 | xv -root -quit -
bggen green black -r 30 -g 32x32 | xv -root -quit -
bggen red black -r 45 -g 32x32 | xv -root -quit -rmode 3 -
bggen red yellow -r 45 -g 32x32 | xv -root -quit -rmode 3 -
John Bradley - firstname.lastname@example.org