juce::PixelAlpha Class Reference

Detailed Description

Represents an 8-bit single-channel pixel, and can perform compositing operations on it.

This is used internally by the imaging classes.

See also

PixelARGB, PixelRGB

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

• juce_graphics/colour/juce_PixelFormats.h

Public Types
enum	{ indexA = 0 }
	The indexes of the different components in the byte layout of this type of colour. More...

Public Member Functions
	PixelAlpha () noexcept=default
	Creates a pixel without defining its colour.
forcedinline constexpr	PixelAlpha (uint8 alpha) noexcept
	Creates a pixel.
forcedinline constexpr uint32	getNativeARGB () const noexcept
	Returns a uint32 which represents the pixel in a platform dependent format which is compatible with the native format of a PixelARGB.
forcedinline constexpr uint32	getInARGBMaskOrder () const noexcept
	Returns a uint32 which will be in argb order as if constructed with the following mask operation ((alpha << 24) | (red << 16) | (green << 8) | blue).
forcedinline uint32 constexpr	getInARGBMemoryOrder () const noexcept
	Returns a uint32 which when written to memory, will be in the order a, r, g, b.
forcedinline constexpr uint32	getEvenBytes () const noexcept
	Return channels with an even index and insert zero bytes between them.
forcedinline constexpr uint32	getOddBytes () const noexcept
	Return channels with an odd index and insert zero bytes between them.
forcedinline constexpr uint8	getAlpha () const noexcept
forcedinline constexpr uint8	getRed () const noexcept
forcedinline constexpr uint8	getGreen () const noexcept
forcedinline constexpr uint8	getBlue () const noexcept
template<class Pixel>
forcedinline constexpr void	set (Pixel src) noexcept
	Copies another pixel colour over this one.
forcedinline constexpr void	setARGB (uint8 a_, uint8, uint8, uint8) noexcept
	Sets the pixel's colour from individual components.
template<class Pixel>
forcedinline constexpr void	blend (Pixel src) noexcept
	Blends another pixel onto this one.
template<class Pixel>
forcedinline constexpr void	blend (Pixel src, uint32 extraAlpha) noexcept
	Blends another pixel onto this one, applying an extra multiplier to its opacity.
template<class Pixel>
forcedinline void	blend (const Pixel &src, BlendMode mode, uint32 extraAlpha=255u) noexcept
	Blends another pixel onto this one using the specified blend mode and applying an extra multiplier to its opacity.
template<class Pixel>
forcedinline constexpr void	tween (Pixel src, uint32 amount) noexcept
	Blends another pixel with this one, creating a colour that is somewhere between the two, as specified by the amount.
forcedinline constexpr void	setAlpha (uint8 newAlpha) noexcept
	Replaces the colour's alpha value with another one.
forcedinline constexpr void	multiplyAlpha (int multiplier) noexcept
	Multiplies the colour's alpha value with another one.
forcedinline constexpr void	multiplyAlpha (float multiplier) noexcept
forcedinline constexpr void	premultiply () noexcept
	Premultiplies the pixel's RGB values by its alpha.
forcedinline constexpr void	unpremultiply () noexcept
	Unpremultiplies the pixel's RGB values.
forcedinline constexpr void	desaturate () noexcept

Member Enums

anonymous enum

anonymous enum

The indexes of the different components in the byte layout of this type of colour.

Enumerator
indexA

Constructors and Destructors

PixelAlpha() [1/2]

juce::PixelAlpha::PixelAlpha ( )

defaultnoexcept

Creates a pixel without defining its colour.

Referenced by PixelAlpha().

PixelAlpha() [2/2]

forcedinline constexpr juce::PixelAlpha::PixelAlpha ( uint8 alpha )

inlineconstexprnoexcept

Creates a pixel.

References forcedinline, and PixelAlpha().

Member Functions

getNativeARGB()

forcedinline constexpr uint32 juce::PixelAlpha::getNativeARGB ( ) const

inlineconstexprnoexcept

Returns a uint32 which represents the pixel in a platform dependent format which is compatible with the native format of a PixelARGB.

See also

PixelARGB::getNativeARGB

References forcedinline.

Referenced by getInARGBMaskOrder(), and getInARGBMemoryOrder().

getInARGBMaskOrder()

forcedinline constexpr uint32 juce::PixelAlpha::getInARGBMaskOrder ( ) const

inlineconstexprnoexcept

Returns a uint32 which will be in argb order as if constructed with the following mask operation ((alpha << 24) | (red << 16) | (green << 8) | blue).

References forcedinline, and getNativeARGB().

getInARGBMemoryOrder()

forcedinline uint32 constexpr juce::PixelAlpha::getInARGBMemoryOrder ( ) const

inlineconstexprnoexcept

Returns a uint32 which when written to memory, will be in the order a, r, g, b.

In other words, if the return-value is read as a uint8 array then the elements will be in the order of a, r, g, b

References forcedinline, and getNativeARGB().

getEvenBytes()

forcedinline constexpr uint32 juce::PixelAlpha::getEvenBytes ( ) const

inlineconstexprnoexcept

Return channels with an even index and insert zero bytes between them.

This is useful for blending operations. The exact channels which are returned is platform dependent but compatible with the return value of getEvenBytes of the PixelARGB class.

See also

PixelARGB::getEvenBytes

References forcedinline.

getOddBytes()

forcedinline constexpr uint32 juce::PixelAlpha::getOddBytes ( ) const

inlineconstexprnoexcept

Return channels with an odd index and insert zero bytes between them.

This is useful for blending operations. The exact channels which are returned is platform dependent but compatible with the return value of getOddBytes of the PixelARGB class.

See also

PixelARGB::getOddBytes

References forcedinline.

getAlpha()

forcedinline constexpr uint8 juce::PixelAlpha::getAlpha ( ) const

inlineconstexprnoexcept

References forcedinline.

getRed()

forcedinline constexpr uint8 juce::PixelAlpha::getRed ( ) const

inlineconstexprnoexcept

References forcedinline.

getGreen()

forcedinline constexpr uint8 juce::PixelAlpha::getGreen ( ) const

inlineconstexprnoexcept

References forcedinline.

getBlue()

forcedinline constexpr uint8 juce::PixelAlpha::getBlue ( ) const

inlineconstexprnoexcept

References forcedinline.

set()

template<class Pixel>

forcedinline constexpr void juce::PixelAlpha::set ( Pixel src )

inlineconstexprnoexcept

Copies another pixel colour over this one.

This doesn't blend it - this colour is simply replaced by the other one.

References forcedinline.

setARGB()

forcedinline constexpr void juce::PixelAlpha::setARGB ( uint8 a_, uint8 , uint8 , uint8  )

inlineconstexprnoexcept

Sets the pixel's colour from individual components.

References forcedinline.

blend() [1/3]

template<class Pixel>

forcedinline constexpr void juce::PixelAlpha::blend ( Pixel src )

inlineconstexprnoexcept

Blends another pixel onto this one.

This takes into account the opacity of the pixel being overlaid, and blends it accordingly.

References forcedinline.

blend() [2/3]

template<class Pixel>

forcedinline constexpr void juce::PixelAlpha::blend ( Pixel src, uint32 extraAlpha )

inlineconstexprnoexcept

Blends another pixel onto this one, applying an extra multiplier to its opacity.

The opacity of the pixel being overlaid is scaled by the extraAlpha factor before being used, so this can blend semi-transparently from a PixelRGB argument.

References forcedinline.

blend() [3/3]

template<class Pixel>

forcedinline void juce::PixelAlpha::blend ( const Pixel & src, BlendMode mode, uint32 extraAlpha = 255u )

inlinenoexcept

Blends another pixel onto this one using the specified blend mode and applying an extra multiplier to its opacity.

The opacity of the pixel being overlaid is scaled by the extraAlpha factor before being used, so this can blend semi-transparently from a PixelRGB argument.

Unlike the similar function of the PixelARGB and PixelRGB classes, full opacity is represented by extraAlpha = 255.

References juce::destinationIn, juce::destinationOut, forcedinline, jassertfalse, juce::source, and juce::sourceOver.

tween()

template<class Pixel>

forcedinline constexpr void juce::PixelAlpha::tween ( Pixel src, uint32 amount )

inlineconstexprnoexcept

Blends another pixel with this one, creating a colour that is somewhere between the two, as specified by the amount.

References forcedinline.

setAlpha()

forcedinline constexpr void juce::PixelAlpha::setAlpha ( uint8 newAlpha )

inlineconstexprnoexcept

Replaces the colour's alpha value with another one.

References forcedinline.

multiplyAlpha() [1/2]

forcedinline constexpr void juce::PixelAlpha::multiplyAlpha ( int multiplier )

inlineconstexprnoexcept

Multiplies the colour's alpha value with another one.

References forcedinline.

multiplyAlpha() [2/2]

forcedinline constexpr void juce::PixelAlpha::multiplyAlpha ( float multiplier )

inlineconstexprnoexcept

References forcedinline.

premultiply()

forcedinline constexpr void juce::PixelAlpha::premultiply ( )

inlineconstexprnoexcept

Premultiplies the pixel's RGB values by its alpha.

References forcedinline.

unpremultiply()

forcedinline constexpr void juce::PixelAlpha::unpremultiply ( )

inlineconstexprnoexcept

Unpremultiplies the pixel's RGB values.

References forcedinline.

desaturate()

forcedinline constexpr void juce::PixelAlpha::desaturate ( )

inlineconstexprnoexcept

References forcedinline.