Name
bw-imp — convert a black and white bw image file to imPRESS bitmap
Synopsis
bw-imp [-D ] [-s squaresize] [-w width] [-n height] [-t thresh] [-X page_xoff] [-Y page_yoff] [file]
DESCRIPTION
bw-imp converts an 8-bit monochrome bw(5) format file (read from the standard input if not specified) to Imagen imPRESS language codes for plotting a gray-scale image on a 300dpi Imagen laser printer.
The gray level is plotted on the
Imagen
as a small pattern of dots,
by default using "ordered dither",
magnifying each input pixel into multiple output pixels.
The
-D
option causes the gray levels to instead be plotted using halftones,
as in newspaper/magazine reproductions of photographs.
The
-t
option turns off the dithering, and uses the supplied integer value
as a threshold value.
Input pixels with magnitude >= thresh are output as white,
otherwise they are output as black.
Each input pixel produces exactly one output pixel.
If the input file is already bi-level, such as might be produced by the
halftone(1)
program, then this is the option to be used.
Printing is done in portrait mode.
The largest image which can generally be printed on an 8.5 by 11 inch
piece of paper is 2240 by 3200 pixels,
and the default page offsets are calculated for this size.
For smaller images, such as 512 squared,
-X750
and
-Y1200
produce the image roughly centered on the page.
EXAMPLES
The following invocations are fairly typical:
pix-bw -ntsc image.pix | bw-imp | qpr -qi300 &
rle-pix image.rle | pix-bw -ntsc | bw-imp | qpr -qi300 &
The X and Y options in the bw-imp command below are to approximately center a 1024x1024 or 512x512 figure on a 8.5 by 11 inch sheet of paper. As of release 4.0 the default margins on an output page resulting from a bw-imp usage are smaller. This allows a larger image to be printed on one page.
rle-pix image.rle | pix-bw -ntsc | bw-imp -X 200 -Y 800 | ipr -L impress -q i300
To threshold and invert the black/white sense of a pix file, use:
bwmod -m -8 -a 255 image.pix | pix-bw | bw-imp -t1 | ttcp -t -p35 printhost
To use the halftone package:
pix-bw -ntsc image.pix | halftone | bw-imp | qpr -qi300 &
