PIXBACKGND(1)

NAME

pixbackgnd - generate a pix(5) shaded background

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SYNOPSIS
DESCRIPTION
OPTIONS
EXAMPLES
SEE ALSO
AUTHOR
COPYRIGHT
BUG REPORTS

SYNOPSIS

pixbackgnd [-H] [-i] [-s squaresize] [-w width] [-n height] [-t title_height] [-a top_inten] [-b bottom_inten] hue saturation > file.pix
pixbackgnd [-H] [-i] [-s squaresize] [-w width] [-n height] [-t title_height] [-a top_inten] [-b bottom_inten] red green blue > file.pix

pixbackgnd generates a pix(5) format shaded background on standard output, suitable for use as a backdrop for presentation slides. The color is specified either as a hue and saturation pair or as an explicit red green blue triple; in both cases the component values range from 0 to 255 inclusive and may be chosen interactively with fbcolor(1). A hue of 160 is a pleasing blue.

The upper title_height scanlines are drawn at the constant top intensity, followed by a 4 scanline white bar, after which the intensity of the chosen color smoothly ramps down to the bottom intensity over the remainder of the image. By default the top intensity is 240 and the bottom intensity is 50; these may be overridden with the -a and -b options.

The output defaults to 512x512 pixels. The -w and -n options set the width and height independently, while -s sets both at once. The -H flag selects a 1024x1024 image and also raises the title area to 90 scanlines.

Output is written to standard output and must be redirected to a file or pipe; pixbackgnd refuses to write pix(5) data to a terminal.

OPTIONS

-H: High resolution. Produce a 1024x1024 image instead of 512x512, and set the title height to 90 scanlines.
-i: Invert the output, writing scanlines top to bottom rather than the bottom-to-top order normally used for pix(5) data.
-s squaresize: Set both the width and the height to squaresize pixels.
-w width: Set the output width to width pixels.
-n height: Set the output height to height pixels.
-t title_height: Set the height in scanlines of the constant-intensity title area at the top of the image (default 80, or 90 with -H).
-a top_inten: Set the top (starting) intensity in the range 0 to 255 (default 240).
-b bottom_inten: Set the bottom (ending) intensity in the range 0 to 255 (default 50).

EXAMPLES

Example 1. Composite a foreground image onto a shaded backdrop

pixbackgnd 160 200 | pixmerge fg.pix - | pix-fb

Generate a blue shaded background (hue 160, saturation 200), merge an existing foreground image fg.pix over it with pixmerge(1), and display the result on a framebuffer with pix-fb(1).

Example 2. Produce a high-resolution untitled backdrop

pixbackgnd -H -a 200 -b 30 160 200 > backdrop.pix

Write a 1024x1024 backdrop with a stronger top-to-bottom intensity ramp (from 200 down to 30) to the file backdrop.pix for later compositing.