; docformat = 'rst' ; ; NAME: ; cgBlendImage ; ; PURPOSE: ; This alpha blends two 24-bit images and displays them with the cgImage command. ; ;******************************************************************************************; ; ; ; Copyright (c) 2011, 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. ; ;******************************************************************************************; ; ;+ ; This alpha blends two 24-bit images and displays them with the cgImage command. ; ; The program requires the `Coyote Library ` ; to be installed on your machine. ; ; :Categories: ; Graphics ; ; :Params: ; 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. ; ; :Keywords: ; 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 ; pixels. ; 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 ; inheritance. ; ; :Author: ; FANNING SOFTWARE CONSULTING:: ; David W. Fanning ; 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 ; ; :History: ; Change History:: ; Written by: David W. Fanning, 26 May 2009. ; Added the WINDOW keyword. 16 February 2012. DWF. ; ; :Copyright: ; Copyright (c) 2009-2012, Fanning Software Consulting, Inc. ;- PRO cgBlendImage, foreGroundImage, backGroundImage, $ ALPHA=alpha, $ WINDOW=window, $ _REF_EXTRA=extra ; Error handling. Catch, theError IF theError NE 0 THEN BEGIN void = cgErrorMsg() RETURN ENDIF ; Handle the window keyword IF N_Elements(window) NE 0 THEN BEGIN ; Save the current graphics window. Be aware that this may be -1. thisWindow = !D.Window ; How many elements are in the WINDOW keyword? CASE N_Elements(window) OF 1: BEGIN WSet, window[0] foreGroundImage = cgSnapshot() IF thisWindow GE 0 THEN BEGIN WSet, thisWindow ENDIF ELSE BEGIN cgDisplay, /Force, /Match, /Free ENDELSE backGroundImage = cgSnapshot() END 2: BEGIN WSet, window[0] foreGroundImage = cgSnapshot() WSet, window[1] backGroundImage = cgSnapshot() cgDisplay, /Force, /Match, /Free END 3: BEGIN WSet, window[0] foreGroundImage = cgSnapshot() WSet, window[1] backGroundImage = cgSnapshot() IF WindowAvailable(window[2]) THEN BEGIN WSet, window[2] ENDIF ELSE BEGIN cgDisplay, /Force, /Match, /Free ENDELSE END ELSE: Message, 'WINDOW keyword must contain no more than three elements.' ENDCASE ENDIF ; Need a foreground and a background image. IF (N_Elements(foregroundImage) EQ 0) || (N_Elements(backgroundImage) EQ 0) $ 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, _STRICT_EXTRA=extra END