is an IRIS Explorer module for creating color maps. Ramp
waves of variable frequency are used to establish a relationship
between data values and colors. Colors may be specified in the
RGB (Red, Green, Blue), HLS (Hue, Lightness, Saturation), and HSV
(Hue, Saturation, Value) color spaces.
WaveformColormap's output is a one dimensional floating point lattice
of 4-tuples, of length 256. Each entry in the output lattice
is a color vector with Red, Green, Blue, and Opacity components.
Opacity here is 1 minus Transparency,
and is set to the constant value one.
The 256 color values are mapped uniformly on the minimum and maximum
data domain values.
- Palette Window
- GenerateColormap has a Palette window to show the current colormap.
- Color Sliders
- WaveFormColormap uses six
parameters to specify the evolution of colors over a range of data
values. Two controls are used for each parameter in the current color
space. The first control is the initial value of the parameter, and
the second is the rate of change applied to it over the map.
When the controlled parameter reaches its limit of zero or one, it is
wrapped back into the space. This way, bands of color may be repeated
over the map.
- Color Space
- The Color Space option menu chooses either the RGB, HLS, or HSV
color space. When the color space is changed, the sliders
control new parameters, and the output map changes.
- Data Range
- The two dials select the Minimum and Maximum of the domain of the
color map. The defaults are zero and one, respectively.
borrows code from xloadimage to initialize color visuals, and therefore
must present this copyright notice:
- The default controls for WaveFormColormap operate in HSV
space. Hue is set by the first two sliders to start at zero (Red),
and increase at the rate of 0.9. By the end of the map, the Hue
parameter has risen to 0.9 (magenta). The other two parameters,
Saturation and Value, are set to values of one. Because their rates
are zero, the color maintains an equal Saturation and Value across the map.
- Cool Ice
- Change the color space to HLS.
Set the Hue to 0.65 (Blue), with a small negative (-0.1) rate of change.
Use the second two sliders to start at a medium Lightness (0.5), and
move up to white by the end (rate equal 0.5).
Leave the last two controls set for a constant Saturation of one.
These settings give a Cool Ice map, useful for indicating
- Hot Iron
- Still in HLS
space, set Hue at zero, with a small positive rate (0.2). Set the
initial Lightness to zero, and let it increase to max at the end of
the range (rate equal one). Again leaving Saturation at a constant
one, results in a Hot Iron color map, approximating the black body
curve for thermal emission. This map is useful for representing
- In HLS space, set Hue to its defaults: initial Value of zero, and rate of 0.9
to take it nearly through the spectrum. Set initial Lightness to
zero, and use a rate of five. Leave Saturation at a constant value of
one. This map gives five sharply defined lightness bands, which are made
distinct by their unique hues. A map of this kind can be used to
introduce simulated contouring in a rendered image.
Copyright 1989, 1990, 1991 Jim Frost
Permission to use, copy, modify, distribute, and sell this software
and its documentation for any purpose is hereby granted without fee,
provided that the above copyright notice appear in all copies and
that both that copyright notice and this permission notice appear
in supporting documentation. The author makes no representations
about the suitability of this software for any purpose. It is
provided "as is" without express or implied warranty.
THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN
NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, INDIRECT OR
CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE
USE OR PERFORMANCE OF THIS SOFTWARE.
Port: First Value
Port: First Rate
Port: Second Value
Port: Second Rate
Port: Third Value
Port: Third Rate
Type: Drawing Area
Port: Color Space
Type: Option Menu
Menu Item: RGB
Menu Item: HLS
Menu Item: HSV
Port: Min Domain
Port: Max Domain
UNIX ports only:
When using X Pseudo-Color Visuals with limited bit planes,
WaveFormColormap can fail to allocate the color cells required for its
display, and fail to execute.
© The Numerical Algorithms Group Ltd, Oxford UK. 2000