PixelAlpha Class Reference

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

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 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 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).
uint32	getInARGBMemoryOrder () const noexcept
	Returns a uint32 which when written to memory, will be in the order a, r, g, b.
forcedinline uint32	getEvenBytes () const noexcept
	Return channels with an even index and insert zero bytes between them.
forcedinline uint32	getOddBytes () const noexcept
	Return channels with an odd index and insert zero bytes between them.
forcedinline uint8	getAlpha () const noexcept
forcedinline uint8	getRed () const noexcept
forcedinline uint8	getGreen () const noexcept
forcedinline uint8	getBlue () const noexcept
template<class Pixel>
forcedinline void	set (const Pixel &src) noexcept
	Copies another pixel colour over this one.
forcedinline void	setARGB (uint8 a_, uint8, uint8, uint8) noexcept
	Sets the pixel's colour from individual components.
template<class Pixel>
forcedinline void	blend (const Pixel &src) noexcept
	Blends another pixel onto this one.
template<class Pixel>
forcedinline void	blend (const Pixel &src, uint32 extraAlpha) noexcept
	Blends another pixel onto this one, applying an extra multiplier to its opacity.
template<class Pixel>
forcedinline void	tween (const 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 void	setAlpha (uint8 newAlpha) noexcept
	Replaces the colour's alpha value with another one.
forcedinline void	multiplyAlpha (int multiplier) noexcept
	Multiplies the colour's alpha value with another one.
forcedinline void	multiplyAlpha (float multiplier) noexcept
forcedinline void	premultiply () noexcept
	Premultiplies the pixel's RGB values by its alpha.
forcedinline void	unpremultiply () noexcept
	Unpremultiplies the pixel's RGB values.
forcedinline void	desaturate () noexcept

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

Member Enumeration Documentation

anonymous enum

anonymous enum

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

Enumerator
indexA

Constructor & Destructor Documentation

PixelAlpha()

PixelAlpha::PixelAlpha ( )

defaultnoexcept

Creates a pixel without defining its colour.

Member Function Documentation

getNativeARGB()

forcedinline uint32 PixelAlpha::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.

See also

PixelARGB::getNativeARGB

References forcedinline, and getNativeARGB().

Referenced by getInARGBMaskOrder(), getInARGBMemoryOrder(), and getNativeARGB().

getInARGBMaskOrder()

forcedinline uint32 PixelAlpha::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).

References forcedinline, and getNativeARGB().

getInARGBMemoryOrder()

uint32 PixelAlpha::getInARGBMemoryOrder ( ) const

noexcept

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 getNativeARGB().

getEvenBytes()

forcedinline uint32 PixelAlpha::getEvenBytes ( ) const

noexcept

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 uint32 PixelAlpha::getOddBytes ( ) const

noexcept

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 uint8 PixelAlpha::getAlpha ( ) const

noexcept

References forcedinline.

getRed()

forcedinline uint8 PixelAlpha::getRed ( ) const

noexcept

References forcedinline.

getGreen()

forcedinline uint8 PixelAlpha::getGreen ( ) const

noexcept

References forcedinline.

getBlue()

forcedinline uint8 PixelAlpha::getBlue ( ) const

noexcept

References forcedinline.

set()

template<class Pixel>

forcedinline void PixelAlpha::set ( const Pixel & src )

noexcept

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 void PixelAlpha::setARGB ( uint8 a_, uint8 , uint8 , uint8  )

noexcept

Sets the pixel's colour from individual components.

References forcedinline.

blend() [1/2]

template<class Pixel>

forcedinline void PixelAlpha::blend ( const Pixel & src )

noexcept

Blends another pixel onto this one.

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

References forcedinline.

blend() [2/2]

template<class Pixel>

forcedinline void PixelAlpha::blend ( const Pixel & src, uint32 extraAlpha )

noexcept

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.

tween()

template<class Pixel>

forcedinline void PixelAlpha::tween ( const 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.

References forcedinline.

setAlpha()

forcedinline void PixelAlpha::setAlpha ( uint8 newAlpha )

noexcept

Replaces the colour's alpha value with another one.

References forcedinline.

multiplyAlpha() [1/2]

forcedinline void PixelAlpha::multiplyAlpha ( int multiplier )

noexcept

Multiplies the colour's alpha value with another one.

References forcedinline.

multiplyAlpha() [2/2]

forcedinline void PixelAlpha::multiplyAlpha ( float multiplier )

noexcept

References forcedinline.

premultiply()

forcedinline void PixelAlpha::premultiply ( )

noexcept

Premultiplies the pixel's RGB values by its alpha.

References forcedinline.

unpremultiply()

forcedinline void PixelAlpha::unpremultiply ( )

noexcept

Unpremultiplies the pixel's RGB values.

References forcedinline.

desaturate()

forcedinline void PixelAlpha::desaturate ( )

noexcept

References forcedinline.