GEOMETRY commands


PROGRAM NAME

ggencmap - Create a Visualization Colormap

DESCRIPTION

ggencmap is used to create a "visualization colormap." A "visualization colormap" is different from a garden variety colormap in one important way. The visualization colormap uses a part of the location segment to indicate how colors are mapped from scalar data. In normal colormaps, a "pixel" value is used as an index into the colormap, producing some new value(s). Using this scheme, it is not possible to have perform mapping functions on floating point or large integer data.

The visualization colormap uses values in the location segment which effectively "bracket" entries in the map. In other words, the user may define a range of values which map to a particular map entry, thus producing non-linear and discontinuous mapping or transfer functions.

The transfer function, or brackets, as computed by this kroutine is linear, and evenly spread across the number of colormap entries. Two methods of computation are provided:

The default method is to compute the minimum and maximum values for the transfer function such that each is two standard deviations away from the mean of a dataset (which is required if this method is chosen).

The default method is to require the user to provide the minimum and maximum values for the transfer function as input to this kroutine.

The color information in the colormap may be specified in either RGB or HSV space, each of which has it's own advantages and disadvantages. The alpha, or opacity, channel is optionally specified seperately from the color information.

Many of the visualization modules in the Geometry toolbox make use of the visualization colormap. Any object which meets the following criteria can be used as a visualization colormap (the magic cookie restriction has been lifted, but colormaps with the magic cookie will still be processed):

Width = Number of map entries Height=Depth=1 Elements=3 or 4 (3==RGB, 4==RGBA)

REQUIRED ARGUMENTS

-outf
type: outfile
desc: output vis colormap

Mutually Exclusive Group; you must specify ONE of:

ALL OF the Mutually Inclusive Group:

-use_hsv
type: flag
desc: color parameters in HSV space
AND
-hs
type: float
desc: hue start value
default: 0
bounds: 0 < [-hs] < 1
AND
-he
type: float
desc: hue end value
default: 1
bounds: 0 < [-he] < 1
AND
-ss
type: float
desc: saturation start value
default: 1
bounds: 0 < [-ss] < 1
AND
-se
type: float
desc: saturation end value
default: 1
bounds: 0 < [-se] < 1
AND
-vs
type: float
desc: value start value
default: 1
bounds: 0 < [-vs] < 1
AND
-ve
type: float
desc: value end value
default: 1
bounds: 0 < [-ve] < 1

ALL OF the Mutually Inclusive Group:

-use_rgb
type: flag
desc: color parameters in RGB space
AND
-rs
type: float
desc: red start value
default: 0
bounds: 0 < [-rs] < 1
AND
-re
type: float
desc: red end value
default: 1
bounds: 0 < [-re] < 1
AND
-gs
type: float
desc: green start value
default: 1
bounds: 0 < [-gs] < 1
AND
-ge
type: float
desc: green end value
default: 1
bounds: 0 < [-ge] < 1
AND
-bs
type: float
desc: blue start value
default: 1
bounds: 0 < [-bs] < 1
AND
-be
type: float
desc: blue end value
default: 1
bounds: 0 < [-be] < 1

OPTIONAL ARGUMENTS

-n
type: integer
desc: number of entries in the vis colormap.
default: 256
bounds: 2 < [-n] < 512

Mutually Inclusive Group; if desired, specify ALL of:

-use_alpha
type: flag
desc: include opacity info in alpha channel of colormap
AND
-as
type: float
desc: alpha start value
default: 0
bounds: 0 < [-as] < 1
AND
-ae
type: float
desc: alpha end value
default: 1
bounds: 0 < [-ae] < 1

Mutually Exclusive Group; if desired, specify ONE of:

ALL OF the Mutually Inclusive Group:

-minval
type: float
desc: value used for minimum bracket value in vis colormap
default: 0
bounds: no range checking
AND
-maxval
type: float
desc: value assioated with maximum bracket value in map.
default: 255
bounds: no range checking

ALL OF the Mutually Inclusive Group:

-i
type: infile
desc: input data
default: {none}
AND
-std_dev_scale
type: float
desc: Scale applied to computed standard deviation in setting min/max values.
default: 3
bounds: value > 0.0

EXAMPLES

SEE ALSO

RESTRICTIONS

REFERENCES

COPYRIGHT

Copyright (C) 1996,1997 , The Regents of the University of California. All rights reserved.