map scalar values into colors via a lookup table More...

#include <vtkLookupTable.h>

Inheritance diagram for vtkLookupTable:

Collaboration diagram for vtkLookupTable:

Public Types
typedef vtkScalarsToColors	Superclass

Public Member Functions
virtual vtkTypeBool	IsA (const char *type)

vtkLookupTable *	NewInstance () const

void	PrintSelf (ostream &os, vtkIndent indent) VTK_OVERRIDE

int	IsOpaque () VTK_OVERRIDE

int	Allocate (int sz=256, int ext=256)

void	Build () VTK_OVERRIDE

virtual void	ForceBuild ()

void	BuildSpecialColors ()

virtual void	SetRamp (int)

void	SetRampToLinear ()

void	SetRampToSCurve ()

void	SetRampToSQRT ()

virtual int	GetRamp ()

void	SetScale (int scale)

void	SetScaleToLinear ()

void	SetScaleToLog10 ()

virtual int	GetScale ()

void	SetTableRange (double r[2])

virtual void	SetTableRange (double min, double max)

virtual double *	GetTableRange ()

virtual void	GetTableRange (double data[2])

virtual void	SetHueRange (double, double)

void	SetHueRange (double[2])

virtual double *	GetHueRange ()

virtual void	GetHueRange (double &, double &)

virtual void	GetHueRange (double[2])

virtual void	SetSaturationRange (double, double)

void	SetSaturationRange (double[2])

virtual double *	GetSaturationRange ()

virtual void	GetSaturationRange (double &, double &)

virtual void	GetSaturationRange (double[2])

virtual void	SetValueRange (double, double)

void	SetValueRange (double[2])

virtual double *	GetValueRange ()

virtual void	GetValueRange (double &, double &)

virtual void	GetValueRange (double[2])

virtual void	SetAlphaRange (double, double)

void	SetAlphaRange (double[2])

virtual double *	GetAlphaRange ()

virtual void	GetAlphaRange (double &, double &)

virtual void	GetAlphaRange (double[2])

virtual void	SetNanColor (double, double, double, double)

virtual void	SetNanColor (double[4])

virtual double *	GetNanColor ()

virtual void	GetNanColor (double &, double &, double &, double &)

virtual void	GetNanColor (double[4])

unsigned char *	GetNanColorAsUnsignedChars ()

virtual void	SetBelowRangeColor (double, double, double, double)

virtual void	SetBelowRangeColor (double[4])

virtual double *	GetBelowRangeColor ()

virtual void	GetBelowRangeColor (double &, double &, double &, double &)

virtual void	GetBelowRangeColor (double[4])

virtual void	SetUseBelowRangeColor (int)

virtual int	GetUseBelowRangeColor ()

virtual void	UseBelowRangeColorOn ()

virtual void	UseBelowRangeColorOff ()

virtual void	SetAboveRangeColor (double, double, double, double)

virtual void	SetAboveRangeColor (double[4])

virtual double *	GetAboveRangeColor ()

virtual void	GetAboveRangeColor (double &, double &, double &, double &)

virtual void	GetAboveRangeColor (double[4])

virtual void	SetUseAboveRangeColor (int)

virtual int	GetUseAboveRangeColor ()

virtual void	UseAboveRangeColorOn ()

virtual void	UseAboveRangeColorOff ()

unsigned char *	MapValue (double v) VTK_OVERRIDE

void	GetColor (double x, double rgb[3]) VTK_OVERRIDE

double	GetOpacity (double v) VTK_OVERRIDE

virtual vtkIdType	GetIndex (double v)

void	SetNumberOfTableValues (vtkIdType number)

vtkIdType	GetNumberOfTableValues ()

virtual void	SetTableValue (vtkIdType indx, double rgba[4])

virtual void	SetTableValue (vtkIdType indx, double r, double g, double b, double a=1.0)

double *	GetTableValue (vtkIdType id)

void	GetTableValue (vtkIdType id, double rgba[4])

unsigned char *	GetPointer (const vtkIdType id)

unsigned char *	WritePointer (const vtkIdType id, const int number)

double *	GetRange () VTK_OVERRIDE

void	SetRange (double min, double max) VTK_OVERRIDE

void	SetRange (double rng[2])

virtual void	SetNumberOfColors (vtkIdType)

virtual vtkIdType	GetNumberOfColors ()

void	SetTable (vtkUnsignedCharArray *)

virtual vtkUnsignedCharArray *	GetTable ()

void	MapScalarsThroughTable2 (void input, unsigned char output, int inputDataType, int numberOfValues, int inputIncrement, int outputIncrement) VTK_OVERRIDE

void	DeepCopy (vtkScalarsToColors *lut) VTK_OVERRIDE

int	UsingLogScale () VTK_OVERRIDE

vtkIdType	GetNumberOfAvailableColors () VTK_OVERRIDE

void	GetIndexedColor (vtkIdType idx, double rgba[4]) VTK_OVERRIDE

Static Public Member Functions
static vtkLookupTable *	New ()

static vtkTypeBool	IsTypeOf (const char *type)

static vtkLookupTable *	SafeDownCast (vtkObjectBase *o)

static void	GetColorAsUnsignedChars (const double colorIn[4], unsigned char colorOut[4])

static void	GetLogRange (const double range[2], double log_range[2])

static double	ApplyLogScale (double v, const double range[2], const double log_range[2])

Static Public Attributes
static const vtkIdType	BELOW_RANGE_COLOR_INDEX

static const vtkIdType	ABOVE_RANGE_COLOR_INDEX

static const vtkIdType	NAN_COLOR_INDEX

static const vtkIdType	NUMBER_OF_SPECIAL_COLORS

Protected Member Functions
virtual vtkObjectBase *	NewInstanceInternal () const

	vtkLookupTable (int sze=256, int ext=256)

void	ResizeTableForSpecialColors ()

Protected Attributes
vtkIdType	NumberOfColors

vtkUnsignedCharArray *	Table

double	TableRange [2]

double	HueRange [2]

double	SaturationRange [2]

double	ValueRange [2]

double	AlphaRange [2]

double	NanColor [4]

double	BelowRangeColor [4]

int	UseBelowRangeColor

double	AboveRangeColor [4]

int	UseAboveRangeColor

int	Scale

int	Ramp

vtkTimeStamp	InsertTime

vtkTimeStamp	BuildTime

double	RGBA [4]

unsigned char	NanColorChar [4]

int	OpaqueFlag

vtkTimeStamp	OpaqueFlagBuildTime

Detailed Description

map scalar values into colors via a lookup table

vtkLookupTable is an object that is used by mapper objects to map scalar values into RGBA (red-green-blue-alpha transparency) color specification, or RGBA into scalar values. The color table can be created by direct insertion of color values, or by specifying a hue, saturation, value, and alpha range and generating a table.

A special color for NaN values in the data can be specified via SetNanColor(). In addition, a color for data values below the lookup table range minimum can be specified with SetBelowRangeColor(), and that color will be used for values below the range minimum when UseBelowRangeColor is on. Likewise, a color for data values above the lookup table range maximum can be specified with SetAboveRangeColor(), and it is used when UseAboveRangeColor is on.

This class behaves differently depending on how IndexedLookup is set. When true, vtkLookupTable enters a mode for representing categorical color maps. By setting IndexedLookup to true, you indicate that the annotated values are the only valid values for which entries in the color table should be returned. The colors in the lookup Table are assigned to annotated values by taking the modulus of their index in the list of annotations. IndexedLookup changes the behavior of GetIndex, which in turn changes the way MapScalarsThroughTable2 behaves; when IndexedLookup is true, MapScalarsThroughTable2 will search for scalar values in AnnotatedValues and use the resulting index to determine the color. If a scalar value is not present in AnnotatedValues, then NanColor will be used.

Warning: You need to explicitly call Build() when constructing the LUT by hand.

See also: vtkLogLookupTable vtkWindowLevelLookupTable

Member Function Documentation

◆ Allocate()

int vtkLookupTable::Allocate	(	int	sz = `256`,
		int	ext = `256`
	)

Allocate a color table of specified size.

◆ ApplyLogScale()

static double vtkLookupTable::ApplyLogScale	(	double	v,
		const double	range[2],
		const double	log_range[2]
	)

static

Apply log to value, with appropriate constraints.

◆ Build()

void vtkLookupTable::Build ( )

Generate lookup table from hue, saturation, value, alpha min/max values. Table is built from linear ramp of each value.

◆ BuildSpecialColors()

void vtkLookupTable::BuildSpecialColors ( )

Copies the "special" colors into the given table.

◆ DeepCopy()

void vtkLookupTable::DeepCopy ( vtkScalarsToColors * lut )

Copy the contents from another LookupTable

◆ ForceBuild()

virtual void vtkLookupTable::ForceBuild ( )

virtual

Force the lookup table to regenerate from hue, saturation, value, and alpha min/max values. Table is built from a linear ramp of each value. ForceBuild() is useful if a lookup table has been defined manually (using SetTableValue) and then an application decides to rebuild the lookup table using the implicit process.

◆ GetColor()

void vtkLookupTable::GetColor	(	double	x,
		double	rgb[3]
	)

Map one value through the lookup table and return the color as an RGB array of doubles between 0 and 1.

◆ GetColorAsUnsignedChars()

static void vtkLookupTable::GetColorAsUnsignedChars	(	const double	colorIn[4],
		unsigned char	colorOut[4]
	)

static

Cast a double color in a type T color. colorIn and colorOut are expected to be RGBA[4] and colorIn to be in [0.0, 1.0]

◆ GetIndex()

virtual vtkIdType vtkLookupTable::GetIndex ( double v )

virtual

Return the table index associated with a particular value.

Do not use this function when IndexedLookup is true: in that case, the set of values v may take on is exactly the integers from 0 to GetNumberOfTableValues() - 1; and v serves directly as an index into TableValues.

◆ GetIndexedColor()

void vtkLookupTable::GetIndexedColor	(	vtkIdType	idx,
		double	rgba[4]
	)

Return a color given an integer index.

This is used to assign colors to annotations (given an offset into the list of annotations). If the table is empty or idx < 0, then NanColor is returned.

◆ GetLogRange()

static void vtkLookupTable::GetLogRange	(	const double	range[2],
		double	log_range[2]
	)

static

Returns the log of range in log_range. There is a little more to this than simply taking the log10 of the two range values: we do conversion of negative ranges to positive ranges, and conversion of zero to a 'very small number'.

◆ GetNanColorAsUnsignedChars()

unsigned char* vtkLookupTable::GetNanColorAsUnsignedChars ( )

Return the NanColor as a pointer to 4 unsigned chars. This will overwrite any data returned by previous calls to MapValue.

◆ GetNumberOfAvailableColors()

vtkIdType vtkLookupTable::GetNumberOfAvailableColors ( )

Get the number of available colors for mapping to.

◆ GetOpacity()

double vtkLookupTable::GetOpacity ( double v )

Map one value through the lookup table and return the alpha value (the opacity) as a double between 0 and 1.

◆ GetPointer()

unsigned char* vtkLookupTable::GetPointer ( const vtkIdType id )

inline

Get pointer to color table data. Format is array of unsigned char r-g-b-a-r-g-b-a...

◆ GetRange()

double* vtkLookupTable::GetRange ( )

inline

Sets/Gets the range of scalars which will be mapped. This is a duplicate of Get/SetTableRange.

◆ GetTableValue() [1/2]

double* vtkLookupTable::GetTableValue ( vtkIdType id )

Return a rgba color value for the given index into the lookup table. Color components are expressed as [0,1] double values.

◆ GetTableValue() [2/2]

void vtkLookupTable::GetTableValue	(	vtkIdType	id,
		double	rgba[4]
	)

Return a rgba color value for the given index into the lookup table. Color components are expressed as [0,1] double values.

◆ IsOpaque()

int vtkLookupTable::IsOpaque ( )

Return true if all of the values defining the mapping have an opacity equal to 1.

◆ MapScalarsThroughTable2()

void vtkLookupTable::MapScalarsThroughTable2	(	void *	input,
		unsigned char *	output,
		int	inputDataType,
		int	numberOfValues,
		int	inputIncrement,
		int	outputIncrement
	)

map a set of scalars through the lookup table

This member function is thread safe.

◆ MapValue()

unsigned char* vtkLookupTable::MapValue ( double v )

Map one value through the lookup table.

◆ New()

static vtkLookupTable* vtkLookupTable::New ( )

static

Construct with range=[0,1]; and hsv ranges set up for rainbow color table (from red to blue).

◆ ResizeTableForSpecialColors()

void vtkLookupTable::ResizeTableForSpecialColors ( )

protected

Resize the LookupTable to have enough room for the out-of-range colors

◆ SetAboveRangeColor()

virtual void vtkLookupTable::SetAboveRangeColor	(	double	,
		double	,
		double	,
		double
	)

virtual

Set the color to use when a value above the range is encountered. This is an RGBA 4-tuple of doubles in the range [0, 1].

◆ SetAlphaRange()

virtual void vtkLookupTable::SetAlphaRange	(	double	,
		double
	)

virtual

Set the range in alpha (using automatic generation). Alpha ranges from [0,1].

◆ SetBelowRangeColor()

virtual void vtkLookupTable::SetBelowRangeColor	(	double	,
		double	,
		double	,
		double
	)

virtual

Set the color to use when a value below the range is encountered. This is an RGBA 4-tuple of doubles in the range [0, 1].

◆ SetHueRange()

virtual void vtkLookupTable::SetHueRange	(	double	,
		double
	)

virtual

Set the range in hue (using automatic generation). Hue ranges between [0,1].

◆ SetNanColor()

virtual void vtkLookupTable::SetNanColor	(	double	,
		double	,
		double	,
		double
	)

virtual

Set the color to use when a NaN (not a number) is encountered. This is an RGBA 4-tuple of doubles in the range [0,1].

◆ SetNumberOfColors()

virtual void vtkLookupTable::SetNumberOfColors ( vtkIdType )

virtual

Set the number of colors in the lookup table. Use SetNumberOfTableValues() instead, it can be used both before and after the table has been built whereas SetNumberOfColors() has no effect after the table has been built.

◆ SetNumberOfTableValues()

void vtkLookupTable::SetNumberOfTableValues ( vtkIdType number )

Specify the number of values (i.e., colors) in the lookup table.

◆ SetRamp()

virtual void vtkLookupTable::SetRamp ( int )

virtual

Set the shape of the table ramp to either linear or S-curve. The default is S-curve, which tails off gradually at either end. The equation used for the S-curve is y = (sin((x - 1/2)*pi) + 1)/2, while the equation for the linear ramp is simply y = x. For an S-curve greyscale ramp, you should set NumberOfTableValues to 402 (which is 256*pi/2) to provide room for the tails of the ramp. The equation for the SQRT is y = sqrt(x).

◆ SetSaturationRange()

virtual void vtkLookupTable::SetSaturationRange	(	double	,
		double
	)

virtual

Set the range in saturation (using automatic generation). Saturation ranges between [0,1].

◆ SetScale()

void vtkLookupTable::SetScale ( int scale )

Set the type of scale to use, linear or logarithmic. The default is linear. If the scale is logarithmic, then the TableRange must not cross the value zero.

◆ SetTable()

void vtkLookupTable::SetTable ( vtkUnsignedCharArray * )

Set/Get the internal table array that is used to map the scalars to colors. The table array is an unsigned char array with 4 components representing RGBA.

◆ SetTableRange()

void vtkLookupTable::SetTableRange ( double r[2] )

Set/Get the minimum/maximum scalar values for scalar mapping. Scalar values less than minimum range value are clamped to minimum range value. Scalar values greater than maximum range value are clamped to maximum range value.

The TableRange values are only used when IndexedLookup is false.

◆ SetTableValue() [1/2]

virtual void vtkLookupTable::SetTableValue	(	vtkIdType	indx,
		double	r,
		double	g,
		double	b,
		double	a = `1.0`
	)

virtual

Directly load color into lookup table. Use [0,1] double values for color component specification.

◆ SetTableValue() [2/2]

virtual void vtkLookupTable::SetTableValue	(	vtkIdType	indx,
		double	rgba[4]
	)

virtual

Directly load color into lookup table. Use [0,1] double values for color component specification. Make sure that you've either used the Build() method or used SetNumberOfTableValues() prior to using this method.

◆ SetUseAboveRangeColor()

virtual void vtkLookupTable::SetUseAboveRangeColor ( int )

virtual

Set whether the below range color should be used.

◆ SetUseBelowRangeColor()

virtual void vtkLookupTable::SetUseBelowRangeColor ( int )

virtual

Set whether the below range color should be used.

◆ SetValueRange()

virtual void vtkLookupTable::SetValueRange	(	double	,
		double
	)

virtual

Set the range in value (using automatic generation). Value ranges between [0,1].

◆ UsingLogScale()

int vtkLookupTable::UsingLogScale ( )

inline

This should return 1 is the subclass is using log scale for mapping scalars to colors. Returns 1 is scale == VTK_SCALE_LOG10.

◆ WritePointer()

unsigned char * vtkLookupTable::WritePointer	(	const vtkIdType	id,
		const int	number
	)

inline

Get pointer to data. Useful for direct writes into object. MaxId is bumped by number (and memory allocated if necessary). Id is the location you wish to write into; number is the number of rgba values to write.

Warning: If you modify the table data via the pointer returned by this member function, you must call vtkLookupTable::BuildSpecialColors() afterwards to ensure that the special colors (below/above range and NaN value) are up-to-date.

Member Data Documentation

◆ BELOW_RANGE_COLOR_INDEX

const vtkIdType vtkLookupTable::BELOW_RANGE_COLOR_INDEX

static

Constants for offsets of special colors (e.g., NanColor, BelowRangeColor, AboveRangeColor) from the maximum index in the lookup table.

The documentation for this class was generated from the following file:

vtkLookupTable.h

Public Types

Public Member Functions

Static Public Member Functions

Static Public Attributes

Protected Member Functions

Protected Attributes

Detailed Description

Member Function Documentation

◆ Allocate()

◆ ApplyLogScale()

◆ Build()

◆ BuildSpecialColors()

◆ DeepCopy()

◆ ForceBuild()

◆ GetColor()

◆ GetColorAsUnsignedChars()

◆ GetIndex()

◆ GetIndexedColor()

◆ GetLogRange()

◆ GetNanColorAsUnsignedChars()

◆ GetNumberOfAvailableColors()

◆ GetOpacity()

◆ GetPointer()

◆ GetRange()

◆ GetTableValue() [1/2]

◆ GetTableValue() [2/2]

◆ IsOpaque()

◆ MapScalarsThroughTable2()

◆ MapValue()

◆ New()

◆ ResizeTableForSpecialColors()

◆ SetAboveRangeColor()

◆ SetAlphaRange()

◆ SetBelowRangeColor()

◆ SetHueRange()

◆ SetNanColor()

◆ SetNumberOfColors()

◆ SetNumberOfTableValues()

◆ SetRamp()

◆ SetSaturationRange()

◆ SetScale()

◆ SetTable()

◆ SetTableRange()

◆ SetTableValue() [1/2]

◆ SetTableValue() [2/2]

◆ SetUseAboveRangeColor()

◆ SetUseBelowRangeColor()

◆ SetValueRange()

◆ UsingLogScale()

◆ WritePointer()

Member Data Documentation

◆ BELOW_RANGE_COLOR_INDEX