cgnormalize.pro
5.76 KB
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; docformat = 'rst'
;
; NAME:
; cgNormalize
;
; PURPOSE:
; This is a utility routine to calculate the scaling vector required to position
; a graphics primitive of specified range at a specific position in an arbitray
; coordinate system.
;
;******************************************************************************************;
; ;
; Copyright (c) 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 calculate the scaling vector required to position a
; graphics primitive of specified range at a specific position in an arbitray coordinate
; system. The scaling vector is given as a two-element array like this::
;
; scalingVector = [translationFactor, scalingFactor]
;
; The scaling vector should be used with the [XYZ]COORD_CONV keywords of a graphics object
; or model. For example, if you wanted to scale an X axis into the coordinate range of
; -0.5 to 0.5, you might type something like this::
;
; xAxis->GetProperty, Range=xRange
; xScale = cgNormalize(xRange, Position=[-0.5, 0.5])
; xAxis, XCoord_Conv=xScale
;
; :Categories:
; Graphics Utility
;
; :Params:
; range: in, required
; A two-element vector specifying the data range.
;
; :Keywords:
; position: in, optional, type=float
; A two-element vector specifying the location in the coordinate system you
; are scaling into. The vector [0.0,1.0] is used by default if Position is not
; specified.
;
; :Examples:
; Here is how to use this program::
;
; xAxis->GetProperty, Range=xRange
; xScale = cgNormalize(xRange, Position=[-0.5, 0.5])
; xAxis, XCoord_Conv=xScale
;
; :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, OCT 1997.
; Fixed a problem with illegal divide by zero. 21 April 2005. DWF.
; Fixed a problem when range[0] is greater than range[1]. 11 July 2006. DWF.
; Renamed to FSC_Normalize to avoid conflicts with 10,000 other programs named NORMALIZE. 17 October 2008. DWF.
; Renamed to cgNormalize 6 February 2013. DWF.
; The number I chose (1e-12) to fix the illegal divide by zero problem was too large. I'm now using
; 1d-25 instead. 9 September 2013. DWF.
;
; :Copyright:
; Copyright (c)1997-2013, Fanning Software Consulting, Inc.
;-
FUNCTION cgNormalize, range, Position=position
On_Error, 2 ; Return to caller.
IF N_Params() EQ 0 THEN Message, 'Please pass range vector as argument.'
IF (N_Elements(position) EQ 0) THEN position = [0.0D, 1.0D] ELSE $
position=Double(position)
range = Double(range)
IF range[1] GE range[0] THEN BEGIN
scale = [((position[0]*range[1])-(position[1]*range[0])) / $
((range[1]-range[0]) > 1d-25), (position[1]-position[0])/((range[1]-range[0]) > 1d-25)]
ENDIF ELSE BEGIN
scale = [((position[1]*range[0])-(position[0]*range[1])) / $
((range[0]-range[1]) > 1d-25), (position[1]-position[0])/((range[0]-range[1]) > 1d-25)]
scale[1] = -scale[1]
ENDELSE
RETURN, scale
END
;-------------------------------------------------------------------------