facade::png::PixelSpan< PixelType > Class Template Reference

A span of data representing the underlying bits or bytes of a pixel. More...

#include <png.hpp>

Public Member Functions
	PixelSpan ()
	PixelSpan (const PixelSpan &other)
Pixel	operator[] (std::size_t index) const
	Syntactic sugar to get a facade::png::Pixel variant out of this span.
const std::uint8_t *	data () const
	Return the underlying raw byte data representing this pixel span.
std::size_t	data_size () const
	Return the size of this pixel span.
Pixel	get (std::size_t index=0) const
	Retrieve a facade::png::Pixel variant of the underlying pixel type at the given index.
void	set (const Pixel &pixel, std::size_t index=0)
	Set a given facade::png::Pixel variant at the given offset.

Static Public Attributes
static const std::size_t	Samples = (8 / PixelType::Bits) + static_cast<int>(PixelType::Bits > 8)
	The amount of samples possibly contained within this pixel span.

Detailed Description

template<typename PixelType>
class facade::png::PixelSpan< PixelType >

A span of data representing the underlying bits or bytes of a pixel.

This class is the binary bridge which allows us to access pixel data that is less than 8 bits in size. It relies on a union of a byte and a byte array to contain as low as 1-bit pixels (with 8 samples) and as large as 64-bit pixels (with 1 sample). This design is necessary to properly type pixel data as it exists within raw PNG image data, allowing us to essentially create objects such as vectors of pixels, which then become a facade::png::ScanlineBase.

Template Parameters

PixelType

The base pixel type to use for this span of pixel data.

Constructor & Destructor Documentation

PixelSpan() [1/2]

template<typename PixelType >

facade::png::PixelSpan< PixelType >::PixelSpan ( )

inline

PixelSpan() [2/2]

template<typename PixelType >

facade::png::PixelSpan< PixelType >::PixelSpan ( const PixelSpan< PixelType > &  other )

inline

Member Function Documentation

data()

template<typename PixelType >

const std::uint8_t * facade::png::PixelSpan< PixelType >::data ( ) const

inline

Return the underlying raw byte data representing this pixel span.

data_size()

template<typename PixelType >

std::size_t facade::png::PixelSpan< PixelType >::data_size ( ) const

inline

Return the size of this pixel span.

get()

template<typename PixelType >

Pixel facade::png::PixelSpan< PixelType >::get ( std::size_t  index = 0 ) const

inline

Retrieve a facade::png::Pixel variant of the underlying pixel type at the given index.

Parameters

index

The index of the sample in the pixel to retrieve. 0 for anything over or equal to 8-bit, anything less than facade::png::PixelSpan::Samples for less than 8-bit.

Exceptions

facade::exception::OutOfBounds

operator[]()

template<typename PixelType >

Pixel facade::png::PixelSpan< PixelType >::operator[] ( std::size_t  index ) const

inline

Syntactic sugar to get a facade::png::Pixel variant out of this span.

Parameters

index

The index of the sample to retrieve.

See also

facade::png::PixelSpan::get

set()

template<typename PixelType >

void facade::png::PixelSpan< PixelType >::set ( const Pixel &  pixel, std::size_t  index = 0  )

inline

Set a given facade::png::Pixel variant at the given offset.

Parameters

pixel	The pixel variant to write to the pixel span.
index	The index of the sample to set. For pixels greater than or equal to 8-bits, this should be 0. For pixels less than 8-bits, this can be anything less than facade::png::PixelSpan::Samples.

See also

facade::png::PixelSpan::get

Exceptions

facade::exception::PixelMismatch
facade::exception::OutOfBounds

Member Data Documentation

bits

template<typename PixelType >

std::uint8_t facade::png::PixelSpan< PixelType >::bits

bytes

template<typename PixelType >

std::uint8_t facade::png::PixelSpan< PixelType >::bytes[PixelType::Bits/8]

Samples

template<typename PixelType >

const std::size_t facade::png::PixelSpan< PixelType >::Samples = (8 / PixelType::Bits) + static_cast<int>(PixelType::Bits > 8)

static

The amount of samples possibly contained within this pixel span.

Pixels that are greater than or equal to 8 bits are considered 1 sample.

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

• include/facade/png.hpp