colortest procs

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Last modified: Tue Dec 20 11:48:25 2005.


List of Routines


Routine Descriptions

CT_FIDDLE

[List of Routines]
 NAME:
       ct_fiddle

 PURPOSE:
       To fiddle with the color table.  The user can select which channels 
       of the color table to manipulate.  The user can change the gamma 
       correction and the range of the color table indices.

 CALLING SEQUENCE:
	CT_FIDDLE [, CHANNELS] [, LOW=value] [, HIGH=value] [,
	GAMMA=value] [, GRANGE=[min,max]]

 OPTIONAL INPUTS:
       CHANNELS: A string argument.  CHANNELS sets which color
                 channels ('R' for red, 'G' for green, 'B' for blue) 
                 will be manipulated in the color table.  The user
                 can manipulate one, two or all channels.  To fiddle
                 with the red and blue channels simultaneously,
                 set channels equal to the string 'rb'.

 KEYWORD PARAMETERS:
	LOW = The lowest pixel value to use.  If this parameter is omitted,
	      0 is assumed.  Appropriate values range from 0 to the number 
	      of available colors-1.

	HIGH = The highest pixel value to use.  If this parameter is omitted,
	       the number of colors-1 is assumed.  Appropriate values range 
	       from 0 to the number of available colors-1.

	GAMMA =	Gamma correction factor.  If this value is omitted, 1.0 is 
		assumed.  Gamma correction works by raising the color indices
		to the Gamma power, assuming they are scaled into the range 
		0 to 1.

       GRANGE = The desired range of the gamma axis, a 2-element
                vector.  The first element is the axis minimum, and 
                the second is the maximum. The default is [0.1,10.0].

 OUTPUTS:
       None.

 COMMON BLOCKS:
	COLORS:	The common block that contains R, G, and B color
		tables loaded by LOADCT, HSV, HLS and others.

 SIDE EFFECTS:
	Image display color tables are changed.

 RESTRICTIONS:
       If using TrueColor visual class, color decomposition must be 
       switched off in order for this routine to work.

 EXAMPLE:
       Load the BLUE/GREEN/RED/YELLOW color table and fiddle with 
       the red and blue channels:

       IDL> loadct, 4
       % LOADCT: Loading table BLUE/GREEN/RED/YELLOW
       IDL> ct_fiddle, 'rb'

 MODIFICATION HISTORY:
   08 May 2004  Written by Tim Robishaw, Berkeley
   Heavily modified version of Carl Heiles's DIDDLE.

(See /dzd2/heiles/idl/gen/colortest/ct_fiddle.pro)