Implementation of a color_scale with a continuous input domain that maps explicit domain values to color and opacity using piecewise constant, piecewise linear or piecewise smooth (b-splines) interpolation. More...

#include <transfer_function.h>

Inheritance diagram for cgv::media::transfer_function:

Public Types
enum class	InterpolationMode { kStep , kLinear , kSmooth }
	The interpolation modes supported by the transfer function. More...

using	color_type = cgv::rgb
	The used color type.

using	opacity_type = float
	The used opacity type.

using	color_point_type = std::pair< float, color_type >
	The used color control point type.

using	opacity_point_type = std::pair< float, opacity_type >
	The used opacity control point type.

Public Member Functions
	transfer_function ()
	Construct using default arguments.

	transfer_function (std::initializer_list< color_point_type > colors)
	Construct from a sequence of color control points.

	transfer_function (std::initializer_list< color_point_type > colors, std::initializer_list< opacity_point_type > opacities)
	Construct from separate sequences of color and opacity control points.

bool	is_opaque () const override
	Return whether the color scale maps to opacity.

bool	is_discrete () const override
	See color_scale::is_discrete().

bool	empty () const
	Check whether the transfer function is empty.

void	clear ()
	Clear all color and opacity control points.

void	clear_color_points ()
	Clear color control points only.

void	clear_opacity_points ()
	Clear opacity control points only.

void	set_color_points (const std::vector< color_point_type > &colors)
	Set the color function to use the given control points.

void	set_color_points_from_scheme (const cgv::media::continuous_color_scheme &scheme, size_t n)
	Set the color function to use n uniformly sampled points from the given color scheme.

void	set_opacity_points (const std::vector< opacity_point_type > &opacities)
	Set the opacity function to use the given control points.

void	add_color_point (float x, const color_type &color)
	Add a color point at position x.

void	add_opacity_point (float x, float opacity)
	Add an opacity point at position x.

bool	set_color (size_t index, const color_type &color)
	Set the color of the control point at the given index.

bool	set_color_at (float x, const color_type &color)
	Set the color of the control point at the given position.

bool	set_opacity (size_t index, const opacity_type &opacity)
	Set the opacity of the control point at the given index.

bool	set_opacity_at (float x, const opacity_type &opacity)
	Set the opacity of the control point at the given position.

bool	remove_color_point (float x)
	Remove the color point at position x if it exists.

bool	remove_opacity_point (float x)
	Remove the opacity point at position x if it exists.

const size_t	get_color_point_count () const
	Get the color control point count.

const size_t	get_opacity_point_count () const
	Get the opacity control point count.

const std::vector< color_point_type > &	get_color_points () const
	Get the color control points.

const std::vector< opacity_point_type > &	get_opacity_points () const
	Get the opacity control points.

void	set_domain (cgv::vec2 domain) override
	Set the domain.

void	rescale (cgv::vec2 domain)
	Rescale the color and opactiy functions to the new domain.

float	normalize_value (float value) const override
	See color_scale::normalize_value().

cgv::rgba	map_value (float value) const override
	See color_scale::map_value().

cgv::rgb	get_mapped_color (float value) const override
	See color_scale::get_mapped_color().

float	get_mapped_opacity (float value) const override
	See color_scale::get_mapped_opacity().

std::vector< cgv::rgba >	quantize (size_t count) const override
	See color_scale::quantize().

std::vector< cgv::rgb >	quantize_color (size_t count) const
	Quantize the color function only.

std::vector< float >	quantize_opacity (size_t count) const
	Quantize the opacity function only.

std::vector< float >	get_ticks (size_t request_count) const override
	See color_scale::get_ticks().

void	set_interpolation (InterpolationMode interpolation)
	Set the interpolation mode of the color and opacity function.

void	set_color_interpolation (InterpolationMode interpolation)
	Set the interpolation mode of the color function.

InterpolationMode	get_color_interpolation () const
	Get the interpolation mode of the color function.

void	set_opacity_interpolation (InterpolationMode interpolation)
	Set the interpolation mode of the opacity function.

InterpolationMode	get_opacity_interpolation () const
	Get the interpolation mode of the opacity function.

Public Member Functions inherited from cgv::media::color_scale
virtual	~color_scale ()
	Destruct this color scale.

cgv::vec2	get_domain () const
	Get the input domain of scalars that will be mapped.

virtual void	set_clamped (bool clamped)
	Set whether the input values are clamped to the domain before mapping.

bool	is_clamped () const
	Get whether the input values are clamped to the domain before mapping.

virtual void	set_reversed (bool reverse)
	Set whether the output color ramp is reversed.

bool	is_reversed () const
	Get whether the output color ramp is reversed.

virtual void	set_unknown_color (cgv::rgba color)
	Set the color returned for scalars outside the domain if clamping is disabled.

cgv::rgba	get_unknown_color () const
	Get the color returned for scalars outside the domain if clamping is disabled.

virtual cgv::rgba	get_indexed_color (size_t index) const
	Map a discrete index through the lookup table and return a RGBA color.

virtual size_t	get_indexed_color_count () const
	return the number of available indexed colors.

cgv::data::time_point	get_modified_time () const
	Get the time point of the last modification of this object.

Additional Inherited Members
Protected Member Functions inherited from cgv::media::color_scale
void	modified ()
	Update the object's modified time.

bool	is_unknown (float value) const
	Test whether the value is outside the domain according to the mapping options.

float	map_range_safe (float value, float in_left, float in_right, float out_left, float out_right) const
	Remap a scalar value from an input range to and output range while safely handling empty ranges.

Detailed Description

Implementation of a color_scale with a continuous input domain that maps explicit domain values to color and opacity using piecewise constant, piecewise linear or piecewise smooth (b-splines) interpolation.

Control points of the color and opacity function can be controlled independent of each other.

Definition at line 21 of file transfer_function.h.

Member Typedef Documentation

◆ color_point_type

using cgv::media::transfer_function::color_point_type = std::pair<float, color_type>

The used color control point type.

Definition at line 35 of file transfer_function.h.

◆ color_type

using cgv::media::transfer_function::color_type = cgv::rgb

The used color type.

Definition at line 31 of file transfer_function.h.

◆ opacity_point_type

using cgv::media::transfer_function::opacity_point_type = std::pair<float, opacity_type>

The used opacity control point type.

Definition at line 37 of file transfer_function.h.

◆ opacity_type

using cgv::media::transfer_function::opacity_type = float

The used opacity type.

Definition at line 33 of file transfer_function.h.

Member Enumeration Documentation

◆ InterpolationMode

enum class cgv::media::transfer_function::InterpolationMode

strong

The interpolation modes supported by the transfer function.

Definition at line 24 of file transfer_function.h.

Constructor & Destructor Documentation

◆ transfer_function() [1/3]

cgv::media::transfer_function::transfer_function ( )

inline

Construct using default arguments.

Definition at line 40 of file transfer_function.h.

◆ transfer_function() [2/3]

cgv::media::transfer_function::transfer_function ( std::initializer_list< color_point_type > colors )

Construct from a sequence of color control points.

Sets the domain to the range governed by the control points.

Parameters

colors The control points.

Definition at line 9 of file transfer_function.cxx.

References set_color_points().

◆ transfer_function() [3/3]

cgv::media::transfer_function::transfer_function	(	std::initializer_list< color_point_type >	colors,
		std::initializer_list< opacity_point_type >	opacities
	)

Construct from separate sequences of color and opacity control points.

Sets the domain to excatly cover the minimum and maximum position among all color and opacity control points. Additional control points are added to the ends of the individual piecwise functions if necessary.

Parameters

colors	The color control points.
opacities	The opacity control points.

Definition at line 13 of file transfer_function.cxx.

References set_color_points(), and set_opacity_points().

Member Function Documentation

◆ add_color_point()

void cgv::media::transfer_function::add_color_point	(	float	x,
		const color_type &	color
	)

Add a color point at position x.

Will replace the previous color point at position x if it exists.

Parameters

x	The control point position.
color	The control point color.

Definition at line 56 of file transfer_function.cxx.

References remove_color_point().

Referenced by set_domain().

◆ add_opacity_point()

void cgv::media::transfer_function::add_opacity_point	(	float	x,
		float	opacity
	)

Add an opacity point at position x.

Will replace the previous opacity point at position x if it exists. The opacity is clamped to [0,1].

Parameters

x	The control point position.
opacity	The control point color.

Definition at line 64 of file transfer_function.cxx.

References remove_opacity_point().

Referenced by set_domain().

◆ clear()

void cgv::media::transfer_function::clear ( )

Clear all color and opacity control points.

Definition at line 18 of file transfer_function.cxx.

◆ clear_color_points()

void cgv::media::transfer_function::clear_color_points ( )

Clear color control points only.

Definition at line 24 of file transfer_function.cxx.

◆ clear_opacity_points()

void cgv::media::transfer_function::clear_opacity_points ( )

Clear opacity control points only.

Definition at line 29 of file transfer_function.cxx.

◆ empty()

bool cgv::media::transfer_function::empty ( ) const

inline

Check whether the transfer function is empty.

Returns: true if both color and opacity functions have no control points.

Definition at line 72 of file transfer_function.h.

◆ get_color_interpolation()

InterpolationMode cgv::media::transfer_function::get_color_interpolation ( ) const

inline

Get the interpolation mode of the color function.

Parameters

interpolation The interpolation mode.

Definition at line 241 of file transfer_function.h.

◆ get_color_point_count()

const size_t cgv::media::transfer_function::get_color_point_count ( ) const

inline

Get the color control point count.

Returns: The control point count.

Definition at line 163 of file transfer_function.h.

◆ get_color_points()

const std::vector< color_point_type > & cgv::media::transfer_function::get_color_points ( ) const

inline

Get the color control points.

Returns: The control points.

Definition at line 177 of file transfer_function.h.

◆ get_mapped_color()

cgv::rgb cgv::media::transfer_function::get_mapped_color ( float value ) const

overridevirtual

See color_scale::get_mapped_color().

Reimplemented from cgv::media::color_scale.

Definition at line 205 of file transfer_function.cxx.

References cgv::media::color_scale::get_unknown_color(), and cgv::media::color_scale::is_unknown().

Referenced by map_value(), and set_domain().

◆ get_mapped_opacity()

float cgv::media::transfer_function::get_mapped_opacity ( float value ) const

overridevirtual

See color_scale::get_mapped_opacity().

Reimplemented from cgv::media::color_scale.

Definition at line 211 of file transfer_function.cxx.

Referenced by map_value(), and set_domain().

◆ get_opacity_interpolation()

InterpolationMode cgv::media::transfer_function::get_opacity_interpolation ( ) const

inline

Get the interpolation mode of the opacity function.

Parameters

interpolation The interpolation mode.

Definition at line 253 of file transfer_function.h.

◆ get_opacity_point_count()

const size_t cgv::media::transfer_function::get_opacity_point_count ( ) const

inline

Get the opacity control point count.

Returns: The control point count.

Definition at line 170 of file transfer_function.h.

◆ get_opacity_points()

const std::vector< opacity_point_type > & cgv::media::transfer_function::get_opacity_points ( ) const

inline

Get the opacity control points.

Returns: The control points.

Definition at line 184 of file transfer_function.h.

◆ get_ticks()

std::vector< float > cgv::media::transfer_function::get_ticks ( size_t request_count ) const

overridevirtual

See color_scale::get_ticks().

Implements cgv::media::color_scale.

Definition at line 249 of file transfer_function.cxx.

References cgv::media::color_scale::get_domain().

◆ is_discrete()

bool cgv::media::transfer_function::is_discrete ( ) const

inlineoverridevirtual

See color_scale::is_discrete().

Returns: False.

Implements cgv::media::color_scale.

Definition at line 65 of file transfer_function.h.

◆ is_opaque()

bool cgv::media::transfer_function::is_opaque ( ) const

inlineoverridevirtual

Return whether the color scale maps to opacity.

Returns: True if the opacity function is not empty, false otherwise.

Reimplemented from cgv::media::color_scale.

Definition at line 59 of file transfer_function.h.

◆ map_value()

cgv::rgba cgv::media::transfer_function::map_value ( float value ) const

overridevirtual

See color_scale::map_value().

Reimplemented from cgv::media::color_scale.

Definition at line 198 of file transfer_function.cxx.

References cgv::media::rgb_color_interface< color< T, cm, am > >::B(), cgv::media::rgb_color_interface< color< T, cm, am > >::G(), get_mapped_color(), get_mapped_opacity(), and cgv::media::rgb_color_interface< color< T, cm, am > >::R().

◆ normalize_value()

float cgv::media::transfer_function::normalize_value ( float value ) const

overridevirtual

See color_scale::normalize_value().

Reimplemented from cgv::media::color_scale.

Definition at line 192 of file transfer_function.cxx.

References cgv::media::color_scale::get_domain(), and cgv::media::color_scale::map_range_safe().

◆ quantize()

std::vector< cgv::rgba > cgv::media::transfer_function::quantize ( size_t count ) const

overridevirtual

See color_scale::quantize().

Implements cgv::media::color_scale.

Definition at line 217 of file transfer_function.cxx.

References quantize_color(), and quantize_opacity().

Referenced by quantize_color(), and quantize_opacity().

◆ quantize_color()

std::vector< cgv::rgb > cgv::media::transfer_function::quantize_color ( size_t count ) const

Quantize the color function only.

See quantize().

Definition at line 230 of file transfer_function.cxx.

References cgv::media::color_scale::is_reversed(), and quantize().

Referenced by quantize().

◆ quantize_opacity()

std::vector< float > cgv::media::transfer_function::quantize_opacity ( size_t count ) const

Quantize the opacity function only.

See quantize().

Definition at line 240 of file transfer_function.cxx.

References cgv::media::color_scale::is_reversed(), and quantize().

Referenced by quantize().

◆ remove_color_point()

bool cgv::media::transfer_function::remove_color_point ( float x )

Remove the color point at position x if it exists.

Parameters

x	The position of the control point to be removed.

Returns: True if a point was removed, false otherwise.

Definition at line 110 of file transfer_function.cxx.

References cgv::media::color_scale::modified().

Referenced by add_color_point().

◆ remove_opacity_point()

bool cgv::media::transfer_function::remove_opacity_point ( float x )

Remove the opacity point at position x if it exists.

Parameters

x	The position of the control point to be removed.

Returns: True if a point was removed, false otherwise.

Definition at line 118 of file transfer_function.cxx.

References cgv::media::color_scale::modified().

Referenced by add_opacity_point().

◆ rescale()

void cgv::media::transfer_function::rescale ( cgv::vec2 domain )

Rescale the color and opactiy functions to the new domain.

All control point positions are updated proportionally to fit inside the new domain.

Parameters

domain The new domain.

Definition at line 173 of file transfer_function.cxx.

References cgv::media::color_scale::get_domain(), cgv::media::color_scale::map_range_safe(), and cgv::media::color_scale::set_domain().

◆ set_color()

bool cgv::media::transfer_function::set_color	(	size_t	index,
		const color_type &	color
	)

Set the color of the control point at the given index.

Parameters

index	The index of the control point to modify.
color	The new color.

Returns: False if no point exists at the given index, true otherwise.

Definition at line 72 of file transfer_function.cxx.

References cgv::media::color_scale::modified().

◆ set_color_at()

bool cgv::media::transfer_function::set_color_at	(	float	x,
		const color_type &	color
	)

Set the color of the control point at the given position.

Parameters

x	The position of the control point to modify.
color	The new color.

Returns: False if no point exists at the given position, true otherwise.

Definition at line 81 of file transfer_function.cxx.

References cgv::media::color_scale::modified().

◆ set_color_interpolation()

void cgv::media::transfer_function::set_color_interpolation ( InterpolationMode interpolation )

Set the interpolation mode of the color function.

Parameters

interpolation The interpolation mode.

Definition at line 270 of file transfer_function.cxx.

References cgv::media::color_scale::modified().

◆ set_color_points()

void cgv::media::transfer_function::set_color_points ( const std::vector< color_point_type > & colors )

Set the color function to use the given control points.

Extends the domain if the new control points are outside the current domain.

Parameters

colors The control points.

Definition at line 34 of file transfer_function.cxx.

Referenced by set_color_points_from_scheme(), transfer_function(), and transfer_function().

◆ set_color_points_from_scheme()

void cgv::media::transfer_function::set_color_points_from_scheme	(	const cgv::media::continuous_color_scheme &	scheme,
		size_t	n
	)

Set the color function to use n uniformly sampled points from the given color scheme.

Will set the domain to [0,1]. See also set_color_points().

Parameters

scheme	The color scheme.
n	The number of poitns to sample.

Definition at line 41 of file transfer_function.cxx.

References cgv::media::continuous_color_scheme::quantize(), set_color_points(), cgv::utils::subdivision_sequence(), and cgv::utils::zip().

◆ set_domain()

void cgv::media::transfer_function::set_domain ( cgv::vec2 domain )

overridevirtual

Set the domain.

All control points outside of the new domain will be removed. New control points will be created at the ends of the new domain if they don't already exist. Affects color and opacity functions.

Parameters

domain The new domain.

Reimplemented from cgv::media::color_scale.

Definition at line 126 of file transfer_function.cxx.

References add_color_point(), add_opacity_point(), cgv::media::color_scale::get_domain(), get_mapped_color(), get_mapped_opacity(), and cgv::media::color_scale::modified().

◆ set_interpolation()

void cgv::media::transfer_function::set_interpolation ( InterpolationMode interpolation )

Set the interpolation mode of the color and opacity function.

Parameters

interpolation The interpolation mode.

Definition at line 262 of file transfer_function.cxx.

References cgv::media::color_scale::modified().

◆ set_opacity()

bool cgv::media::transfer_function::set_opacity	(	size_t	index,
		const opacity_type &	opacity
	)

Set the opacity of the control point at the given index.

Parameters

index	The index of the control point to modify.
opacity	The new opacity.

Returns: False if no point exists at the given index, true otherwise.

Definition at line 91 of file transfer_function.cxx.

References cgv::media::color_scale::modified().

◆ set_opacity_at()

bool cgv::media::transfer_function::set_opacity_at	(	float	x,
		const opacity_type &	opacity
	)

Set the opacity of the control point at the given position.

Parameters

x	The position of the control point to modify.
opacity	The new opacity.

Returns: False if no point exists at the given position, true otherwise.

Definition at line 100 of file transfer_function.cxx.

References cgv::media::color_scale::modified().

◆ set_opacity_interpolation()

void cgv::media::transfer_function::set_opacity_interpolation ( InterpolationMode interpolation )

Set the interpolation mode of the opacity function.

Parameters

interpolation The interpolation mode.

Definition at line 277 of file transfer_function.cxx.

References cgv::media::color_scale::modified().

◆ set_opacity_points()

void cgv::media::transfer_function::set_opacity_points ( const std::vector< opacity_point_type > & opacities )

Set the opacity function to use the given control points.

Extends the domain if the new control points are outside the current domain. Opacity values are clamped to [0,1].

Parameters

opacities The control points.

Definition at line 48 of file transfer_function.cxx.

Referenced by transfer_function().

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

cgv/media/transfer_function.h
cgv/media/transfer_function.cxx

Public Types

Public Member Functions

Additional Inherited Members

Detailed Description

Member Typedef Documentation

◆ color_point_type

◆ color_type

◆ opacity_point_type

◆ opacity_type

Member Enumeration Documentation

◆ InterpolationMode

Constructor & Destructor Documentation

◆ transfer_function() [1/3]

◆ transfer_function() [2/3]

◆ transfer_function() [3/3]

Member Function Documentation

◆ add_color_point()

◆ add_opacity_point()

◆ clear()

◆ clear_color_points()

◆ clear_opacity_points()

◆ empty()

◆ get_color_interpolation()

◆ get_color_point_count()

◆ get_color_points()

◆ get_mapped_color()

◆ get_mapped_opacity()

◆ get_opacity_interpolation()

◆ get_opacity_point_count()

◆ get_opacity_points()

◆ get_ticks()

◆ is_discrete()

◆ is_opaque()

◆ map_value()

◆ normalize_value()

◆ quantize()

◆ quantize_color()

◆ quantize_opacity()

◆ remove_color_point()

◆ remove_opacity_point()

◆ rescale()

◆ set_color()

◆ set_color_at()

◆ set_color_interpolation()

◆ set_color_points()

◆ set_color_points_from_scheme()

◆ set_domain()

◆ set_interpolation()

◆ set_opacity()

◆ set_opacity_at()

◆ set_opacity_interpolation()

◆ set_opacity_points()