;+ ; NAME: ; BLENDIMAGE ; ; PURPOSE: ; ; This alpha blends two 24-bit images and displays them with the TVIMAGE command. ; ; AUTHOR: ; ; FANNING SOFTWARE CONSULTING ; David Fanning, Ph.D. ; 1645 Sheely Drive ; Fort Collins, CO 80526 USA ; Phone: 970-221-0438 ; E-mail: david@idlcoyote.com ; Coyote's Guide to IDL Programming: http://www.idlcoyote.com/ ; ; CATEGORY: ; ; Graphics ; ; CALLING SEQUENCE: ; ; BlendImage, foregroundImage, backgroundImage ; ; INPUTS: ; ; foregroundImage: A 24-bit foreground image with the same dimensions as the background image. ; ; backgroundImage: A 24-bit background image with the same dimensions as the foreground image. ; ; KEYWORD PARAMETERS: ; ; ALPHA: 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 ; pixels. By default, 0.5. ; ; Note: Any keywords appropriate to the TVIMAGE command are also accepted. ; ; MODIFICATION HISTORY: ; ; Written by: David W. Fanning, 26 May 2009. ;- ; ;******************************************************************************************; ; Copyright (c) 2009, by Fanning Software Consulting, Inc. ; ; All rights reserved. ; ; ; ; Redistribution and use in source and binary forms, with or without ; ; modification, are permitted provided that the following conditions are met: ; ; ; ; * Redistributions of source code must retain the above copyright ; ; notice, this list of conditions and the following disclaimer. ; ; * Redistributions in binary form must reproduce the above copyright ; ; notice, this list of conditions and the following disclaimer in the ; ; documentation and/or other materials provided with the distribution. ; ; * Neither the name of Fanning Software Consulting, Inc. nor the names of its ; ; contributors may be used to endorse or promote products derived from this ; ; software without specific prior written permission. ; ; ; ; THIS SOFTWARE IS PROVIDED BY FANNING SOFTWARE CONSULTING, INC. ''AS IS'' AND ANY ; ; EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES ; ; OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT ; ; SHALL FANNING SOFTWARE CONSULTING, INC. BE LIABLE FOR ANY DIRECT, INDIRECT, ; ; INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED ; ; TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; ; ; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ; ; ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT ; ; (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS ; ; SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. ; ;******************************************************************************************; PRO BlendImage, foreGroundImage, backGroundImage, ALPHA=alpha, _EXTRA=extra ; Error handling. Catch, theError IF theError NE 0 THEN BEGIN void = Error_Message() RETURN ENDIF ; Need a foreground and a background image. IF N_Params() NE 2 THEN Message, 'Usage: "BlendedImage, foreGroundImage, backGroundImage"' ; Condition alpha blending value. IF N_Elements(alpha) EQ 0 THEN alpha = 0.5 alpha = 0.0 > alpha < 1.0 ; Do input image dimensions match? IF Total( Size(foregroundImage, /DIMENSIONS) EQ Size(backgroundImage, /DIMENSIONS) ) NE 3 $ THEN Message, 'Dimensions and/or size of input images do not match.' ; Output the blended image. cgImage, (foreGroundImage * alpha) + (1 - alpha) * backGroundImage, _EXTRA=extra END