This alpha blends two 24-bit images and displays them with the cgImage command.
foregroundImage: in, required, type=truecolor
A 24-bit foreground image with the same dimensions as the background image.
backgroundImage: in, required, type=truecolor
A 24-bit background image with the same dimensions as the foreground image.
alpha: in, optional, type=float, default=0.5
A number between 0 and 1 that indicates the percentage of the foreground image
to alpha-blend into the background image. For example, ALPHA=0.2 will give
a weigth of 20% to the foreground image pixels and 80% to the background image
window: in, optional, type=intarr
A one-, two-, or three-element array giving the window index numbers for
the foreground, background, and display windows, repectively. If one-element,
the foreground image is retrieved from that window and displayed in the current
window. If two elements, the foreground and background images are obtained from
the first two elements, respectively, and a new third display window is opened.
This is the same for three elements, except the third element is used to specify
the display window.
_ref_extra: in, optional
Any keyword appropriate for the cgImage command is also accepted by keyword
FANNING SOFTWARE CONSULTING::
David W. Fanning
1645 Sheely Drive
Fort Collins, CO 80526 USA
Coyote's Guide to IDL Programming: http://www.idlcoyote.com
Written by: David W. Fanning, 26 May 2009.
Added the WINDOW keyword. 16 February 2012. DWF.
Copyright (c) 2009-2012, Fanning Software Consulting, Inc.