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This program is part of Netpbm.
pamgradient creates an image of the specified dimensions width by height which contains a smooth, two-dimensional gradient between the specified colors of the four corners (from top left to bottom right).
Specify the colors as described for the argument of the pnm_parsecolor() library routine.
If all four colors are gray values, pamgradient creates a grayscale image (PAM tuple type GRAYSCALE). Otherwise, it creates a color image (PAM tuple type RGB).
In addition to the options common to all programs based on libnetpbm (most notably -quiet, see Common Options), pamgradient recognizes the following command line option:
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.
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.
pamgradient was new in Netpbm 10.31 (December 2005).
pamgradient was written by Daniel Haude in October 2005.