Public Member Functions | Static Public Member Functions | Public Attributes | List of all members
ColourGradient Class Referencefinal

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

Public Member Functions

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

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. More...
 

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.

References Rectangle< ValueType >::getBottom(), and Rectangle< ValueType >::getY().

◆ 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
proportionAlongGradienta 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.
colourthe 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
positionthe position along the gradient, between 0 and 1

◆ createLookupTable() [1/2]

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() [2/2]

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.

◆ 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

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.


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