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Pamgradient User Manual
.SH 1
pamgradient
.LP
Updated: 21 October 2005
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Table Of Contents
.SH 2
NAME
.LP
pamgradient - create a four-corner gradient PAM or PNM image
.SH 2
SYNOPSIS
.LP
\fBpamgradient\fR
[\fB-maxval=\fR\fImaxval\fR]
\fIcolor-tl\fR \fIcolor-tr\fR \fIcolor-bl\fR \fIcolor-br\fR
.br
\fIwidth\fR \fIheight\fR
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Minimum unique abbreviation of option is acceptable.  You may use double
hyphens instead of single hyphen to denote options.  You may use white
space in place of the equals sign to separate an option name from its value.
.SH 2
DESCRIPTION
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.LP
This program is part of Netpbm.
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\fBpamgradient\fR creates an image of the specified
dimensions \fIwidth\fR by \fIheight\fR which contains a smooth,
two-dimensional gradient between the specified colors of the four
corners (from top left to bottom right).
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Specify the colors as described for the argument of the \fBppm_parsecolor()\fR
library routine.
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If all four colors are gray values, \fBpamgradient\fR creates a
grayscale image (PAM tuple type GRAYSCALE).  Otherwise, it creates
a color image (PAM tuple type RGB).
.SH 2
OPTIONS
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.RS
.IP "\fB-maxval=\fR\fImaxval\fR"
maxval of the generated image.  (See PAM and
PNM specifications).
.RE
.SH 2
SEE ALSO
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\fBppmmake\fR,
\fBppmrainbow\fR,
\fBpgmramp\fR,
\fBppmpat\fR,
pam,
pnm
.SH 2
NOTE
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Only the top left corner of the generated image has exactly
the specified color.  The color of the top right corner is a bit
shifted to the left, the bottom left corner a bit up, and the
bottom right corner left and up. This ensures nice transitions
when combining adjacent (very narrow) gradients, and doesn't play
a role when the gradient butts against a solid surface.
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This effect is created by the integer arithmetic used for the
interpolation of the color values, and since it doesn't make a
difference for all practical purposes I might as well sell it as a
feature.
.SH 2
HISTORY
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.LP
\fBpamgradient\fR was new in Netpbm 10.31 (December 2005).
.SH 2
AUTHOR
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.LP
pamgradient was written by Daniel Haude in October 2005.
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\l'5i'
.SH 2
Table Of Contents
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NAME
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SYNOPSIS
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DESCRIPTION
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OPTIONS
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SEE ALSO
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NOTE
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HISTORY
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AUTHOR
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