Section: Visualization Toolkit Common Classes
The scalars to color mapping can be augmented with an additional uniform alpha blend. This is used, for example, to blend a vtkActor's opacity with the lookup table values.
To create an instance of class vtkScalarsToColors, simply invoke its constructor as follows
obj = vtkScalarsToColors
obj
is an instance of the vtkScalarsToColors class.
string = obj.GetClassName ()
int = obj.IsA (string name)
vtkScalarsToColors = obj.NewInstance ()
vtkScalarsToColors = obj.SafeDownCast (vtkObject o)
int = obj.IsOpaque ()
- Return true if all of the values defining the mapping have an opacity
equal to 1. Default implementation return true.
obj.Build ()
- Perform any processing required (if any) before processing
scalars.
double = obj.GetRange ()
- Sets/Gets the range of scalars which will be mapped.
obj.SetRange (double min, double max)
- Sets/Gets the range of scalars which will be mapped.
obj.SetRange (double rng[2])
- Map one value through the lookup table and return a color defined
as a RGBA unsigned char tuple (4 bytes).
obj.GetColor (double v, double rgb[3])
- Map one value through the lookup table and return the color as
an RGB array of doubles between 0 and 1.
double = obj.GetColor (double v)
- Map one value through the lookup table and return the alpha value
(the opacity) as a double between 0 and 1.
double = obj.GetOpacity (double )
- Map one value through the lookup table and return the luminance
0.3*red + 0.59*green + 0.11*blue as a double between 0 and 1.
Returns the luminance value for the specified scalar value.
double = obj.GetLuminance (double x)
- Specify an additional opacity (alpha) value to blend with. Values
!= 1 modify the resulting color consistent with the requested
form of the output. This is typically used by an actor in order to
blend its opacity.
obj.SetAlpha (double alpha)
- Specify an additional opacity (alpha) value to blend with. Values
!= 1 modify the resulting color consistent with the requested
form of the output. This is typically used by an actor in order to
blend its opacity.
double = obj.GetAlpha ()
- Specify an additional opacity (alpha) value to blend with. Values
!= 1 modify the resulting color consistent with the requested
form of the output. This is typically used by an actor in order to
blend its opacity.
vtkUnsignedCharArray = obj.MapScalars (vtkDataArray scalars, int colorMode, int component)
- An internal method maps a data array into a 4-component, unsigned char
RGBA array. The color mode determines the behavior of mapping. If
VTK_COLOR_MODE_DEFAULT is set, then unsigned char data arrays are
treated as colors (and converted to RGBA if necessary); otherwise,
the data is mapped through this instance of ScalarsToColors. The offset
is used for data arrays with more than one component; it indicates
which component to use to do the blending.
When the component argument is -1, then the this object uses its
own selected technique to change a vector into a scalar to map.
obj.SetVectorMode (int )
- Change mode that maps vectors by magnitude vs. component.
int = obj.GetVectorMode ()
- Change mode that maps vectors by magnitude vs. component.
obj.SetVectorModeToMagnitude ()
- Change mode that maps vectors by magnitude vs. component.
obj.SetVectorModeToComponent ()
- Change mode that maps vectors by magnitude vs. component.
obj.SetVectorComponent (int )
- If the mapper does not select which component of a vector
to map to colors, you can specify it here.
int = obj.GetVectorComponent ()
- If the mapper does not select which component of a vector
to map to colors, you can specify it here.
obj.MapScalarsThroughTable (vtkDataArray scalars, string output, int outputFormat)
- Map a set of scalars through the lookup table in a single operation.
The output format can be set to VTK_RGBA (4 components),
VTK_RGB (3 components), VTK_LUMINANCE (1 component, greyscale),
or VTK_LUMINANCE_ALPHA (2 components)
If not supplied, the output format defaults to RGBA.
obj.MapScalarsThroughTable (vtkDataArray scalars, string output)
- An internal method typically not used in applications.
vtkUnsignedCharArray = obj.ConvertUnsignedCharToRGBA (vtkUnsignedCharArray colors, int numComp, int numTuples)
- An internal method used to convert a color array to RGBA. The
method instantiates a vtkUnsignedCharArray and returns it. The user is
responsible for managing the memory.
int = obj.UsingLogScale ()
- This should return 1 is the subclass is using log scale for mapping scalars
to colors. Default implementation returns 0.