ColourGradient Class Reference

Describes the layout and colours that should be used to paint a colour gradient. More...

#include <juce_ColourGradient.h>

Public Member Functions
	ColourGradient () noexcept
	Creates an uninitialised gradient.
	ColourGradient (const ColourGradient &)
	ColourGradient (ColourGradient &&) noexcept
ColourGradient &	operator= (const ColourGradient &)
ColourGradient &	operator= (ColourGradient &&) noexcept
	ColourGradient (Colour colour1, float x1, float y1, Colour colour2, float x2, float y2, bool isRadial)
	Creates a gradient object.
	ColourGradient (Colour colour1, Point< float > point1, Colour colour2, Point< float > point2, bool isRadial)
	Creates a gradient object.
	~ColourGradient ()
	Destructor.
void	clearColours ()
	Removes any colours that have been added.
int	addColour (double proportionAlongGradient, Colour colour)
	Adds a colour at a point along the length of the gradient.
void	removeColour (int index)
	Removes one of the colours from the gradient.
void	multiplyOpacity (float multiplier) noexcept
	Multiplies the alpha value of all the colours by the given scale factor.
int	getNumColours () const noexcept
	Returns the number of colour-stops that have been added.
double	getColourPosition (int index) const noexcept
	Returns the position along the length of the gradient of the colour with this index.
Colour	getColour (int index) const noexcept
	Returns the colour that was added with a given index.
void	setColour (int index, Colour newColour) noexcept
	Changes the colour at a given index.
Colour	getColourAtPosition (double position) const noexcept
	Returns the an interpolated colour at any position along the gradient.
int	createLookupTable (const AffineTransform &transform, HeapBlock< PixelARGB > &resultLookupTable) const
	Creates a set of interpolated premultiplied ARGB values.
void	createLookupTable (PixelARGB *resultLookupTable, int numEntries) const noexcept
	Creates a set of interpolated premultiplied ARGB values.
template<size_t NumEntries>
void	createLookupTable (PixelARGB(&resultLookupTable)[NumEntries]) const noexcept
	Creates a set of interpolated premultiplied ARGB values.
bool	isOpaque () const noexcept
	Returns true if all colours are opaque.
bool	isInvisible () const noexcept
	Returns true if all colours are completely transparent.
bool	operator== (const ColourGradient &) const noexcept
bool	operator!= (const ColourGradient &) const noexcept

Static Public Member Functions
static ColourGradient	vertical (Colour colour1, float y1, Colour colour2, float y2)
	Creates a vertical linear gradient between two Y coordinates.
static ColourGradient	horizontal (Colour colour1, float x1, Colour colour2, float x2)
	Creates a horizontal linear gradient between two X coordinates.
template<typename Type >
static ColourGradient	vertical (Colour colourTop, Colour colourBottom, Rectangle< Type > area)
	Creates a vertical linear gradient from top to bottom in a rectangle.
template<typename Type >
static ColourGradient	horizontal (Colour colourLeft, Colour colourRight, Rectangle< Type > area)
	Creates a horizontal linear gradient from right to left in a rectangle.

Public Attributes
Point< float >	point1
Point< float >	point2
bool	isRadial
	If true, the gradient should be filled circularly, centred around point1, with point2 defining a point on the circumference.

Detailed Description

Describes the layout and colours that should be used to paint a colour gradient.

See also

Graphics::setGradientFill

Constructor & Destructor Documentation

ColourGradient() [1/5]

ColourGradient::ColourGradient ( )

noexcept

Creates an uninitialised gradient.

If you use this constructor instead of the other one, be sure to set all the object's public member variables before using it!

ColourGradient() [2/5]

ColourGradient::ColourGradient

(

const ColourGradient &

)

ColourGradient() [3/5]

ColourGradient::ColourGradient ( ColourGradient && )

noexcept

ColourGradient() [4/5]

ColourGradient::ColourGradient	(	Colour	colour1,
		float	x1,
		float	y1,
		Colour	colour2,
		float	x2,
		float	y2,
		bool	isRadial )

Creates a gradient object.

(x1, y1) is the location to draw with colour1. Likewise (x2, y2) is where colour2 should be. In between them there's a gradient.

If isRadial is true, the colours form a circular gradient with (x1, y1) at its centre.

The alpha transparencies of the colours are used, so note that if you blend from transparent to a solid colour, the RGB of the transparent colour will become visible in parts of the gradient. e.g. blending from Colour::transparentBlack to Colours::white will produce a muddy grey colour midway, but Colour::transparentWhite to Colours::white will be white all the way across.

See also

ColourGradient

ColourGradient() [5/5]

ColourGradient::ColourGradient	(	Colour	colour1,
		Point< float >	point1,
		Colour	colour2,
		Point< float >	point2,
		bool	isRadial )

Creates a gradient object.

point1 is the location to draw with colour1. Likewise point2 is where colour2 should be. In between them there's a gradient.

If isRadial is true, the colours form a circular gradient with point1 at its centre.

The alpha transparencies of the colours are used, so note that if you blend from transparent to a solid colour, the RGB of the transparent colour will become visible in parts of the gradient. e.g. blending from Colour::transparentBlack to Colours::white will produce a muddy grey colour midway, but Colour::transparentWhite to Colours::white will be white all the way across.

See also

ColourGradient

~ColourGradient()

ColourGradient::~ColourGradient

(

)

Destructor.

Member Function Documentation

operator=() [1/2]

ColourGradient & ColourGradient::operator=

(

const ColourGradient &

)

operator=() [2/2]

ColourGradient & ColourGradient::operator= ( ColourGradient && )

noexcept

vertical() [1/2]

static ColourGradient ColourGradient::vertical ( Colour colour1, float y1, Colour colour2, float y2 )

static

Creates a vertical linear gradient between two Y coordinates.

horizontal() [1/2]

static ColourGradient ColourGradient::horizontal ( Colour colour1, float x1, Colour colour2, float x2 )

static

Creates a horizontal linear gradient between two X coordinates.

vertical() [2/2]

template<typename Type >

static ColourGradient ColourGradient::vertical ( Colour colourTop, Colour colourBottom, Rectangle< Type > area )

static

Creates a vertical linear gradient from top to bottom in a rectangle.

horizontal() [2/2]

template<typename Type >

static ColourGradient ColourGradient::horizontal ( Colour colourLeft, Colour colourRight, Rectangle< Type > area )

static

Creates a horizontal linear gradient from right to left in a rectangle.

References Rectangle< ValueType >::getRight(), and Rectangle< ValueType >::getX().

clearColours()

void ColourGradient::clearColours

(

)

Removes any colours that have been added.

This will also remove any start and end colours, so the gradient won't work. You'll need to add more colours with addColour().

addColour()

int ColourGradient::addColour	(	double	proportionAlongGradient,
		Colour	colour )

Adds a colour at a point along the length of the gradient.

This allows the gradient to go through a spectrum of colours, instead of just a start and end colour.

Parameters

proportionAlongGradient	a value between 0 and 1.0, which is the proportion of the distance along the line between the two points at which the colour should occur.
colour	the colour that should be used at this point

Returns

the index at which the new point was added

removeColour()

void ColourGradient::removeColour

(

int

index

)

Removes one of the colours from the gradient.

multiplyOpacity()

void ColourGradient::multiplyOpacity ( float multiplier )

noexcept

Multiplies the alpha value of all the colours by the given scale factor.

getNumColours()

int ColourGradient::getNumColours ( ) const

noexcept

Returns the number of colour-stops that have been added.

getColourPosition()

double ColourGradient::getColourPosition ( int index ) const

noexcept

Returns the position along the length of the gradient of the colour with this index.

The index is from 0 to getNumColours() - 1. The return value will be between 0.0 and 1.0

getColour()

Colour ColourGradient::getColour ( int index ) const

noexcept

Returns the colour that was added with a given index.

The index is from 0 to getNumColours() - 1.

setColour()

void ColourGradient::setColour ( int index, Colour newColour )

noexcept

Changes the colour at a given index.

The index is from 0 to getNumColours() - 1.

getColourAtPosition()

Colour ColourGradient::getColourAtPosition ( double position ) const

noexcept

Returns the an interpolated colour at any position along the gradient.

Parameters

position

the position along the gradient, between 0 and 1

createLookupTable() [1/3]

int ColourGradient::createLookupTable	(	const AffineTransform &	transform,
		HeapBlock< PixelARGB > &	resultLookupTable ) const

Creates a set of interpolated premultiplied ARGB values.

This will resize the HeapBlock, fill it with the colours, and will return the number of colours that it added. When calling this, the ColourGradient must have at least 2 colour stops specified.

createLookupTable() [2/3]

void ColourGradient::createLookupTable ( PixelARGB * resultLookupTable, int numEntries ) const

noexcept

Creates a set of interpolated premultiplied ARGB values.

This will fill an array of a user-specified size with the gradient, interpolating to fit. The numEntries argument specifies the size of the array, and this size must be greater than zero. When calling this, the ColourGradient must have at least 2 colour stops specified.

createLookupTable() [3/3]

template<size_t NumEntries>

void ColourGradient::createLookupTable ( PixelARGB(&) resultLookupTable[NumEntries] ) const

noexcept

Creates a set of interpolated premultiplied ARGB values.

This will fill an array of a user-specified size with the gradient, interpolating to fit. When calling this, the ColourGradient must have at least 2 colour stops specified.

isOpaque()

bool ColourGradient::isOpaque ( ) const

noexcept

Returns true if all colours are opaque.

isInvisible()

bool ColourGradient::isInvisible ( ) const

noexcept

Returns true if all colours are completely transparent.

operator==()

bool ColourGradient::operator== ( const ColourGradient & ) const

noexcept

operator!=()

bool ColourGradient::operator!= ( const ColourGradient & ) const

noexcept

References operator!=(), and operator==().

Member Data Documentation

point1

Point<float> ColourGradient::point1

point2

Point<float> ColourGradient::point2

isRadial

bool ColourGradient::isRadial

If true, the gradient should be filled circularly, centred around point1, with point2 defining a point on the circumference.

If false, the gradient is linear between the two points.

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

• juce_ColourGradient.h