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; docformat = 'rst'
;
; NAME:
; cgScaleVector
;
; PURPOSE:
; This is a utility routine to scale the elements of a vector or an array into a
; given data range.
;
;******************************************************************************************;
; ;
; Copyright (c) 1998-2013, 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 is a utility routine to scale the elements of a vector or an array into a
; given data range.
;
; :Categories:
; Utilities
;
; :Returns:
; A vector or array of the same size as the input, scaled into the data range given
; by `minRange` and `maxRange'. The input vector is confined to the data range set
; by `MinValue` and `MaxValue` before scaling occurs.
;
; :Params:
; maxRange: in, optional, type=varies, default=1
; The maximum output value of the scaled vector. Set to 1 by default.
; minRange: in, optional, type=varies, default=0
; The minimum output value of the scaled vector. Set to 0 by default.
; vector: in, required
; The input vector or array to be scaled.
;
; :Keywords:
; double: in, optional, type=boolean, default=0
; Set this keyword to perform scaling in double precision. Otherwise, scaling
; is done in floating point precision.
; maxvalue: in, optional
; Set this value to the maximum value of the vector, before scaling (vector < maxvalue).
; The default value is Max(vector).
; minvalue: in, optional
; Set this value to the mimimum value of the vector, before scaling (minvalue < vector).
; The default value is Min(vector).
; nan: in, optional, type=boolean, default=0
; Set this keyword to enable not-a-number checking. NANs in vector will be ignored.
; preserve_type: in, optional, type=boolean, default=0
; Set this keyword to preserve the input data type in the output.
;
; :Examples:
; Simple example of scaling a vector::
;
; IDL> x = [3, 5, 0, 10]
; IDL> xscaled = cgScaleVector(x, -50, 50)
; IDL> Print, xscaled
; -20.0000 0.000000 -50.0000 50.0000
; Suppose your image has a minimum value of -1.7 and a maximum value = 2.5.
; You wish to scale this data into the range 0 to 255, but you want to use
; a diverging color table. Thus, you want to make sure value 0.0 is scaled to 128.
; You proceed like this::
;
; scaledImage = cgScaleVector(image, 0, 255, MINVALUE=-2.5, MAXVALUE=2.5)
;
; :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, 12 Dec 1998.
; Added MAXVALUE and MINVALUE keywords. 5 Dec 1999. DWF.
; Added NAN keyword. 18 Sept 2000. DWF.
; Removed check that made minRange less than maxRange to allow ranges to be
; reversed on axes, etc. 28 Dec 2003. DWF.
; Added PRESERVE_TYPE and DOUBLE keywords. 19 February 2006. DWF.
; Added FPUFIX to cut down on floating underflow errors. 11 March 2006. DWF.
; Renamed Scale_Vector to cgScaleVector, 16 May 2013. DWF.
;
; :Copyright:
; Copyright (c) 1998-2013, Fanning Software Consulting, Inc.
;-
FUNCTION cgScaleVector, vector, minRange, maxRange, $
DOUBLE=double, $
MAXVALUE=vectorMax, $
MINVALUE=vectorMin, $
NAN=nan, $
PRESERVE_TYPE=preserve_type
; Error handling.
Catch, theError
IF theError NE 0 THEN BEGIN
Catch, /Cancel
void = Error_Message()
RETURN, vector
ENDIF
; Check positional parameters.
CASE N_Params() OF
0: Message, 'Incorrect number of arguments.'
1: BEGIN
IF Keyword_Set(double) THEN BEGIN
minRange = 0.0D
maxRange = 1.0D
ENDIF ELSE BEGIN
minRange = 0.0
maxRange = 1.0
ENDELSE
ENDCASE
2: BEGIN
IF Keyword_Set(double) THEN maxRange = 1.0D > (minRange + 0.0001D) ELSE $
maxRange = 1.0 > (minRange + 0.0001)
ENDCASE
ELSE:
ENDCASE
; If input data type is DOUBLE and DOUBLE keyword is not set, then set it.
IF Size(FPUFIX(vector), /TNAME) EQ 'DOUBLE' AND N_Elements(double) EQ 0 THEN double = 1
; Make sure we are working with at least floating point numbers.
IF Keyword_Set(double) THEN minRange = DOUBLE( minRange ) ELSE minRange = FLOAT( minRange )
IF Keyword_Set(double) THEN maxRange = DOUBLE( maxRange ) ELSE maxRange = FLOAT( maxRange )
; Make sure we have a valid range.
IF maxRange EQ minRange THEN Message, 'Range max and min are coincidental'
; Check keyword parameters.
IF Keyword_Set(double) THEN BEGIN
IF N_Elements(vectorMin) EQ 0 THEN vectorMin = Double( Min(FPUFIX(vector), NAN=1) ) $
ELSE vectorMin = Double(vectorMin)
IF N_Elements(vectorMax) EQ 0 THEN vectorMax = DOUBLE( Max(FPUFIX(vector), NAN=1) ) $
ELSE vectorMax = DOUBLE( vectorMax )
ENDIF ELSE BEGIN
IF N_Elements(vectorMin) EQ 0 THEN vectorMin = FLOAT( Min(FPUFIX(vector), NAN=1) ) $
ELSE vectorMin = FLOAT( vectorMin )
IF N_Elements(vectorMax) EQ 0 THEN vectorMax = FLOAT( Max(FPUFIX(vector), NAN=Keyword_Set(nan)) ) $
ELSE vectorMax = FLOAT( vectorMax )
ENDELSE
; Trim vector before scaling.
index = Where(Finite(vector) EQ 1, count)
IF count NE 0 THEN BEGIN
IF Keyword_Set(double) THEN trimVector = Double(vector) ELSE trimVector = Float(vector)
trimVector[index] = vectorMin > vector[index] < vectorMax
ENDIF ELSE BEGIN
IF Keyword_Set(double) THEN trimVector = vectorMin > Double(vector) < vectorMax ELSE $
trimVector = vectorMin > Float(vector) < vectorMax
ENDELSE
; Calculate the scaling factors.
scaleFactor = [((minRange * vectorMax)-(maxRange * vectorMin)) / $
(vectorMax - vectorMin), (maxRange - minRange) / (vectorMax - vectorMin)]
; Clear math errors.
void = Check_Math()
; Return the scaled vector.
IF Keyword_Set(preserve_type) THEN BEGIN
RETURN, FPUFIX(Convert_To_Type(trimVector * scaleFactor[1] + scaleFactor[0], Size(vector, /TNAME)))
ENDIF ELSE BEGIN
RETURN, FPUFIX(trimVector * scaleFactor[1] + scaleFactor[0])
ENDELSE
END