IBM Visualization Data Explorer User's Reference

AutoColor

Category

Function

Automatically colors a field.

Syntax


mapped, colormap = AutoColor(data, opacity, intensity, start, range,
                             saturation, min, max, delayed, outofrange);

Inputs

Name Type Default Description
data data field none field to be colored
opacity scalar input dependent opacity, between 0 and 1
intensity scalar 1.0 color intensity
start scalar 0.6666 starting color (default = blue)
range scalar 0.6666 range of color (default = blue to red)
saturation scalar 1 saturation, between 0 and 1
min scalar or data field min of data minimum of data to be colored
max scalar or data field max of data maximum of data to be colored
delayed flag 0 0: apply maps
1: delay applying color and opacity maps (byte data only)
outofrange vector list or string list [.3 .3 .3] how to color out-of-range points

Name	Type	Default	Description
`data`	data field	none	field to be colored
`opacity`	scalar	input dependent	opacity, between 0 and 1
`intensity`	scalar	1.0	color intensity
`start`	scalar	0.6666	starting color (default = blue)
`range`	scalar	0.6666	range of color (default = blue to red)
`saturation`	scalar	1	saturation, between 0 and 1
`min`	scalar or data field	min of data	minimum of data to be colored
`max`	scalar or data field	max of data	maximum of data to be colored
`delayed`	flag	0	0: apply maps 1: delay applying color and opacity maps (byte data only)
`outofrange`	vector list or string list	[.3 .3 .3]	how to color out-of-range points

Outputs

Name Type Description
mapped color field color-mapped input field
colormap field RGB color map used

Name	Type	Description
`mapped`	color field	color-mapped input field
`colormap`	field	RGB color map used

Functional Details

This module colors a specified field (data) by mapping hues to data values.

data
is an input field with data. If the input is a vector field, the colors are based on the magnitude of the data. If the input consists of matrices, the colors are based on the determinants.
opacity
specifies the opacity of the resulting object. Allowed values range from 0 to 1. Its default value is 1 for surfaces and 0.5 for volumes.
intensity
scales the amount of color. For opaque surfaces, the parameter scales from black (0) to full color (1). For volumes, it controls the brightness of the object when viewed along its longest dimension. Values greater than 1 can be used to brighten translucent surfaces or volumes that appear too dim. See also "Coloring Objects for Volume Rendering".
start and start - range
specify the colors applied to the minimum and maximum data values mapped. By default, the minimum data value is colored blue (0.6666), and the maximum is colored red (0 or 1; colors are defined cyclically from -&infinity. to &infinity., so that a start of -1 = 0 =1, and so on).
saturation
specifies the saturation of the colors used. This value must be between 0 and 1.
min and max
specify the minimum and maximum data values mapped. If neither is specified, the minimum and maximum values of data are mapped. If min is scalar, the minimum data value is mapped to that value. If min is a data field, the minimum data value of that field is used.
The max parameter is interpreted in corresponding fashion. If min is a data field and max is unspecified, the module uses the minimum and maximum values of that field.
For volumes, regions with values outside the min-max range are invisible; for surfaces, such regions are gray by default.
delayed
determines whether "delayed colors" are created. Such colors are available only for byte data and they use less memory.
When delayed = 1:

The "colors" component is a pointer to the "data" component, and a "color map" component is created. (This component is a color lookup table with 256 entries, representing the appropriate color for each of the 256 possible data values.)
If opacity is also specified, an opacity map is created with 256 entries, while the "opacities" component is a copy of the "data" component.
The module adds a "direct color map" attribute to the output object. (See "Using Direct Color Maps".)

outofrange
specifies the coloring of data that fall outside the min-max range. This parameter applies only to surfaces; out-of-range data values for volumes are always invisible. If the parameter value is a single color (RGB vector or color-name string), it is applied to both the upper and lower out-of-range points. If it is a list of two colors, then it is applied to the lower and upper out-of-range points, respectively. Color strings can be any of the defined color-name strings (see Color) or either of strings "color of min" and "color of max."

Notes:

AutoColor adds colors to the "colors" component. For "front colors" or "back colors," use the Rename module following AutoColor. (See Appendix E. "Data Explorer Fonts", in IBM Visualization Data Explorer User's Guide.)
This module also outputs the RGB color map used, in the output colormap. The "positions" component contains the data values, and the "data" component contains the corresponding RGB colors. You can use this color map as an input to the ColorBar module. For byte data, the color map always contains 256 entries for the 256 possible data values. If the input to AutoColor is a group, then a different color map will be constructed for each member of the group. In that case, the colormap output of the module is a group of color maps. Use the Select module to select the color map you want to display using ColorBar.
If you AutoColor a group of volumes, you may find that the resulting image is black because the renderer does not support coincident volumes.

Components

Adds a "colors" component. An "opacities" component is added if opacity is less than 1 or if the input data is a volume. If delayed = 1, the "colors" component is a copy of the "data" component and a "color map" component is created. Similarly, an "opacity map" component is created if opacity is less than 1 or the input is a volume.

Example Visual Programs

Many example visual programs use AutoColor, including:

AlternateVisualizations.net
ContoursAndCaption.net
InvalidData.net
MappedIso.net
RubberTube.net
ThunderGlyphSheet.net
VolumeRendering.net
SIMPLE/Autocolor.net

See Also

Color, ColorBar, AutoGrayScale, Display

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`data`	is an input field with data. If the input is a vector field, the colors are based on the magnitude of the data. If the input consists of matrices, the colors are based on the determinants.
`opacity`	specifies the opacity of the resulting object. Allowed values range from 0 to 1. Its default value is 1 for surfaces and 0.5 for volumes.
`intensity`	scales the amount of color. For opaque surfaces, the parameter scales from black (0) to full color (1). For volumes, it controls the brightness of the object when viewed along its longest dimension. Values greater than 1 can be used to brighten translucent surfaces or volumes that appear too dim. See also "Coloring Objects for Volume Rendering".
`start` and `start` - `range`	specify the colors applied to the minimum and maximum data values mapped. By default, the minimum data value is colored blue (0.6666), and the maximum is colored red (0 or 1; colors are defined cyclically from -&infinity. to &infinity., so that a `start` of -1 = 0 =1, and so on).
`saturation`	specifies the saturation of the colors used. This value must be between 0 and 1.
`min` and `max`	specify the minimum and maximum data values mapped. If neither is specified, the minimum and maximum values of `data` are mapped. If `min` is scalar, the minimum data value is mapped to that value. If `min` is a data field, the minimum data value of that field is used. The `max` parameter is interpreted in corresponding fashion. If `min` is a data field and `max` is unspecified, the module uses the minimum and maximum values of that field. For volumes, regions with values outside the `min`-`max` range are invisible; for surfaces, such regions are gray by default.
`delayed`	determines whether "delayed colors" are created. Such colors are available only for byte data and they use less memory. When `delayed` = 1: The "colors" component is a pointer to the "data" component, and a "color map" component is created. (This component is a color lookup table with 256 entries, representing the appropriate color for each of the 256 possible data values.) If `opacity` is also specified, an opacity map is created with 256 entries, while the "opacities" component is a copy of the "data" component. The module adds a "direct color map" attribute to the output object. (See "Using Direct Color Maps".)
`outofrange`	specifies the coloring of data that fall outside the `min`-`max` range. This parameter applies only to surfaces; out-of-range data values for volumes are always invisible. If the parameter value is a single color (RGB vector or color-name string), it is applied to both the upper and lower out-of-range points. If it is a list of two colors, then it is applied to the lower and upper out-of-range points, respectively. Color strings can be any of the defined color-name strings (see Color) or either of strings "color of min" and "color of max."