JUCE  v5.1.1-3-g1a0b28c73
JUCE API
ColourGradient Class Reference

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

#include <juce_ColourGradient.h>

Collaboration diagram for ColourGradient:

Classes

struct  ColourPoint
 

Public Member Functions

 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 () noexcept
 Creates an uninitialised gradient. More...
 
 ~ColourGradient ()
 Destructor. More...
 
int addColour (double proportionAlongGradient, Colour colour)
 Adds a colour at a point along the length of the gradient. More...
 
void clearColours ()
 Removes any colours that have been added. 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...
 
Colour getColour (int index) const noexcept
 Returns the colour that was added with a given index. More...
 
Colour getColourAtPosition (double position) const noexcept
 Returns the an interpolated colour at any position along the gradient. More...
 
double getColourPosition (int index) const noexcept
 Returns the position along the length of the gradient of the colour with this index. More...
 
int getNumColours () const noexcept
 Returns the number of colour-stops that have been added. More...
 
bool isInvisible () const noexcept
 Returns true if all colours are completely transparent. More...
 
bool isOpaque () const noexcept
 Returns true if all colours are opaque. More...
 
void multiplyOpacity (float multiplier) noexcept
 Multiplies the alpha value of all the colours by the given scale factor. More...
 
bool operator!= (const ColourGradient &) const noexcept
 
bool operator== (const ColourGradient &) const noexcept
 
void removeColour (int index)
 Removes one of the colours from the gradient. More...
 
void setColour (int index, Colour newColour) noexcept
 Changes the colour at a given index. More...
 

Public Attributes

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

Private Attributes

Array< ColourPointcolours
 

Detailed Description

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

See also
Graphics::setGradientFill

Constructor & Destructor Documentation

◆ ColourGradient() [1/3]

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() [2/3]

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() [3/3]

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()

ColourGradient::~ColourGradient ( )

Destructor.

Member Function Documentation

◆ 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

◆ 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().

◆ 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.

Referenced by RenderingHelpers::SoftwareRendererSavedState::fillWithGradient().

◆ 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.

◆ 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.

◆ 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

◆ 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

◆ getNumColours()

int ColourGradient::getNumColours ( ) const
noexcept

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

◆ isInvisible()

bool ColourGradient::isInvisible ( ) const
noexcept

Returns true if all colours are completely transparent.

◆ isOpaque()

bool ColourGradient::isOpaque ( ) const
noexcept

Returns true if all colours are opaque.

◆ multiplyOpacity()

void ColourGradient::multiplyOpacity ( float  multiplier)
noexcept

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

Referenced by RenderingHelpers::SavedStateBase< SoftwareRendererSavedState >::fillShape().

◆ operator!=()

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

◆ operator==()

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

◆ removeColour()

void ColourGradient::removeColour ( int  index)

Removes one of the colours from the gradient.

◆ setColour()

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

Changes the colour at a given index.

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

Member Data Documentation

◆ colours

Array<ColourPoint> ColourGradient::colours
private

◆ 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.

Referenced by RenderingHelpers::EdgeTableFillers::renderGradient().

◆ point1

◆ point2


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