beta: in, optional, type=float, default=3.0
The beta factor in a Hyperpolic Sine stretch.
block: in, optional, type=boolean, default=0
Set this keyword if you wish the program to be a blocking widget.
brewer: in, optional, type=boolean, default=0
Set this keyword if you wish to use the Brewer color tables.
colors: in, optional, type=string
A five element string array, listing the colors for drawing the
histogram plot. If a particular color is represented as a null string, then the
default for that color is used. The colors are used as follows::
colors[0] : Background color. Default: "white".
colors[1] : Axis color. Default: "black".
colors[2] : Min threshold color. Default: "firebrick".
colors[3] : Max threshold color. Default: "steel blue".
colors[4] : ASinh color. Default: "grn6".
colors[5] : Histogram color. Default: "charcoal".
colortable: in, optional, type=integer, default=0
The color table to display the image in. By default, gray-scale colors.
constant: in, optional, type=float, default = 1.0
The constant value in a logarithmic stretch.
exclude: in, optional, type=numeric
The value to exclude in a standard deviation stretch.
exponent: in, optional, type=float, default=4.0
The logarithm exponent in a logarithmic stretch.
filename: in, optional, type=string
If no image is supplied as a positional parameter, this keyword can be
used to specify the name of an image file to read with ImageSelect.
gamma: in, optional, type=float, default=1.5
The gamma factor in a gamma stretch.
group_leader: in, optional, type=integer
The identifier of the widget group leader is this program is called from within
a widget program.
max_value: in, optional, type=varies
Use this keyword to assign a maximun value for the normalized Histogram Plot.
Images with lots of pixels of one color (e.g. black) skew the histogram. This
helps make a better looking plot. Set by default to the maximum value of the
histogram data.
maxthresh: in, optional
The initial maximum threshold value for the stretch.
mean: in, optional, type=float, default=0.5
The mean factor in a logarithmic stretch.
minthresh: in, optional
The initial minimun threshold value for the stretch.
multiplier: in, optional, type=float
The multiplication factor in a standard deviation stretch. The standard deviation
is multiplied by this factor to produce the thresholds for a linear stretch.
negative: in, optional, type=boolean, default=0
Set this keyword if you want to display the image with a negative or reverse stretch.
no_window: in, optional, type=boolean, default=0
Set this keyword if you do no want the program to display an image window. This would
be the case, for example, if you are displaying the image in your own window and your program
is being notified of images changes via the `NOTIFY_PRO` or `NOTIFY_OBJ` keywords.
notify_obj: in, optional, type=struct
Set this keyword to a structure containing the fields OBJECT and METHOD. When the image is changed,
the object identified in the OBJECT field will have the method identified in the METHOD
field called. The method should be written to accept one positional parameter. The parameter passed
to the method is a structure defined as below::
struct = { image: stretchedImage, $ ; The stretched image.
r: info.r, $ ; The R color vector associated with the image
g: info.g, $ ; The G color vector associated with the image
b: info.b, $ ; The B color vector associated with the image
type: info.type, $ ; The TYPE of stretch applied to the image.
minThresh: info.minThresh, $ ; The minimum threshold value.
maxThresh: info.maxThresh, $ ; The maximum threshold value.
beta: info.beta, $ ; The current BETA value.
gamma: info.gamma, $ ; The current GAMMA value.
mean: info.mean, $ ; The current MEAN value.
exponent: info.exponent, $ ; The current EXPONENT value.
multiplier: info.multiplier, $ ; The current MULTIPLIER value.
sigma: info.sigma } ; The current SIGMA value.
notify_pro: in, optional, type=string
Set this keyword to the name of a procedure that should be notified when the image is changed.
The procedure should be defined with one positional parameter. The parameter passed
to the procedure is a structure defined in the `Notify_Obj` keyword..
sigma: in, optional, type=float, default=1.0
The sigma scale factor in a Gaussian stretch.
title: in, optional, type=string
The title of the histogram window. By default: 'Drag Vertical Lines to STRETCH Image Contrast'.
type: in, optional, type=integer
The type of stretch to be applied. May be either a string (e.g, 'GAMMA') or a number from the table below::
Number Type of Stretch
0 Linear scaled = BytScl(image, MIN=minThresh, MAX=maxThresh)
1 Gamma scaled = cgGmaScl(image, MIN=minThresh, MAX=maxThresh, Gamma=gamma)
2 Log scaled = cgLogScl(image, MIN=minThresh, MAX=maxThresh, Constant=constant)
3 Asinh scaled = cgAsinhScl(image, MIN=minThresh, MAX=maxThresh, Beta=beta)
4 Linear 2% A linear stretch, with 2 percent of pixels clipped at both the top and bottom
5 Square Root A linear stretch of the square root histogram of the image values.
6 Equalization A linear stretch of the histogram equalized image histogram.
7 Gaussian A Gaussian normal function is applied to the image histogram.
8 StdDev The image is stretched linearly based on its mean and a multiple of its standard deviation.
9 Compression scaled = cgCompressScl(image, MIN=minThresh, MAX=maxThresh, Mean=mean, Exponent=exponent)
uvalue: in, optional
Any IDL variable can be stored in this keyword.
xpos: in, optional, type=integer, default=100
The X position of the histogram window in pixels from upper-left of display.
ypos: in, optional, type=integer, default=100
The Y position of the histogram window in pixels from upper-left of display.