Burger::FilePNG Class Reference

Reads and writes PNG files. More...

Collaboration diagram for Burger::FilePNG:

Public Types
enum	{   PNG_GREYSCALE =0 , PNG_RGB =2 , PNG_INDEXED =3 , PNG_GREYSCALEALPHA =4 ,   PNG_RGBA =6 }

Public Member Functions
const char *	SeekPNGChunk (InputMemoryStream *pInput, uint32_t uID)
	Scan a PNG file in memory and return pointer to a chunk.
const char *	SeekNextPNGChunk (InputMemoryStream *pInput, uint32_t uID)
	Scan a PNG file in memory starting AFTER the previously found chunk and return pointer to a chunk.
	FilePNG ()
	Default constructor.
uint_t	Load (Image *pOutput, InputMemoryStream *pInput)
	Parses a PNG file.
const RGBAWord8_t *	GetPalette (void) const
	Get the file image's palette.
RGBAWord8_t *	GetPalette (void)
	Get the file image's palette.
void	SetPalette (const RGBWord8_t *pInput, uint_t uStartIndex=0, uint_t uPaletteSize=256)
	Set the file image's palette (RGB)
void	SetPalette (const RGBAWord8_t *pInput, uint_t uStartIndex=0, uint_t uPaletteSize=256)
	Set the file image's palette (RGBA)

Static Public Attributes
static const uint32_t	FILETYPE = 0x504E4720
	'PNG ' Mac File type for PNG files (Byte swapped on little endian machines)
static const uint32_t	AUXTYPE = 0x6F676C65
	'ogle' Mac creator code for PNG files (Byte swapped on little endian machines)

Protected Member Functions
const char *	SeekChunk (InputMemoryStream *pInput, uint32_t uID, uintptr_t uStartOffset)
	Scan a PNG file in memory and return pointer to a chunk.

Private Attributes
RGBAWord8_t	m_Palette [256]
	Palette found in the image.
uintptr_t	m_uStartOffset
	PNG file image chunk start offset.
uintptr_t	m_uNextOffset
	Offset to the next chunk.
uint32_t	m_uChunkSize
	Size of the current chunk in bytes.
uint32_t	m_uPNGID
	Untouched ID of the current PNG chunk.

Detailed Description

Reads and writes PNG files.

---

This class will read and write out PNG files and use Burger::Image class instances as data transporters

Member Enumeration Documentation

anonymous enum

anonymous enum

Enumerator
PNG_GREYSCALE	Each pixel is a grayscale sample.
PNG_RGB	Each pixel is an R,G,B triple.
PNG_INDEXED	Each pixel is a palette index;.
PNG_GREYSCALEALPHA	Each pixel is a grayscale sample,.
PNG_RGBA	Each pixel is an R,G,B,A quad,.

Constructor & Destructor Documentation

FilePNG()

Burger::FilePNG::FilePNG

(

)

Default constructor.

---

Initializes all extra file data to defaults

Member Function Documentation

GetPalette() [1/2]

RGBAWord8_t * Burger::FilePNG::GetPalette ( void )

inline

Get the file image's palette.

---

Obtain a pointer to the 256 entry RGBA color palette found in the PNG file

Returns

Pointer to the 256 entry RGBAWord8_t palette

See also

Burger::FilePNG::GetPalette(void) const

GetPalette() [2/2]

const RGBAWord8_t * Burger::FilePNG::GetPalette ( void ) const

inline

Get the file image's palette.

---

Obtain a constant pointer to the 256 entry RGBA color palette found in the PNG file

Returns

Constant pointer to the 256 entry RGBAWord8_t palette

See also

Burger::FilePNG::GetPalette(void)

Load()

uint_t BURGER_API Burger::FilePNG::Load	(	Image *	pOutput,
		InputMemoryStream *	pInput )

Parses a PNG file.

---

Read in a PNG file and set the extra variables

Will parse 8, 16, 24 and 32 bit compressed PNG files only. Other formats are not supported

Note

A descriptive error message is passed to Debug::Warning()

Parameters

pOutput	Pointer to an Image record to store the new image into
pInput	Pointer to a memory stream that has a PNG file image

Returns

Zero for success or non-zero on failure

SeekChunk()

const char * Burger::FilePNG::SeekChunk ( InputMemoryStream * pInput, uint32_t uID, uintptr_t uStartOffset )

protected

Scan a PNG file in memory and return pointer to a chunk.

---

Parameters

pInput	Data stream to read compressed data from
uID	PNG token to scan for (Must be upper case)
uStartOffset	Offset into the stream to begin the scan

Returns

NULL if success or a pointer to a string describing the error

SeekNextPNGChunk()

const char * Burger::FilePNG::SeekNextPNGChunk	(	InputMemoryStream *	pInput,
		uint32_t	uID )

Scan a PNG file in memory starting AFTER the previously found chunk and return pointer to a chunk.

---

Parameters

pInput	Data stream to read compressed data from
uID	PNG token to scan for (Must be upper case)

Returns

NULL if success or a pointer to a string describing the error

SeekPNGChunk()

const char * Burger::FilePNG::SeekPNGChunk	(	InputMemoryStream *	pInput,
		uint32_t	uID )

Scan a PNG file in memory and return pointer to a chunk.

---

Parameters

pInput	Data stream to read compressed data from
uID	PNG token to scan for (Must be upper case)

Returns

NULL if success or a pointer to a string describing the error

SetPalette() [1/2]

void Burger::FilePNG::SetPalette ( const RGBAWord8_t * pInput, uint_t uStartIndex = 0, uint_t uPaletteSize = 256 )

inline

Set the file image's palette (RGBA)

---

Given a pointer to a palette, copy the colors into this class for writing to an 8 bit PNG file.

If the starting index is greater than 255, this function does nothing. If the color entry count exceeds 256 colors, the remaining colors are ignored to prevent buffer overruns

Parameters

pInput	Pointer to the palette to copy
uStartIndex	Color index of the 256 color internal palette to start modification
uPaletteSize	Number of color entries in the palette (Maximum 256)

See also

SetPalette(const RGBWord8_t *,uint_t,uint_t)

SetPalette() [2/2]

void Burger::FilePNG::SetPalette ( const RGBWord8_t * pInput, uint_t uStartIndex = 0, uint_t uPaletteSize = 256 )

inline

Set the file image's palette (RGB)

---

Given a pointer to a palette, copy the colors into this class for writing to an 8 bit PNG file. Since the Alpha is missing from the input, each entry set will have the alpha set to zero.

If the starting index is greater than 255, this function does nothing. If the color entry count exceeds 256 colors, the remaining colors are ignored to prevent buffer overruns

Parameters

pInput	Pointer to the palette to copy
uStartIndex	Color index of the 256 color internal palette to start modification
uPaletteSize	Number of color entries in the palette (Maximum 256)

See also

SetPalette(const RGBAWord8_t *,uint_t,uint_t)

Member Data Documentation

AUXTYPE

const uint32_t Burger::FilePNG::AUXTYPE = 0x6F676C65

static

'ogle' Mac creator code for PNG files (Byte swapped on little endian machines)

FILETYPE

const uint32_t Burger::FilePNG::FILETYPE = 0x504E4720

static

'PNG ' Mac File type for PNG files (Byte swapped on little endian machines)

m_Palette

RGBAWord8_t Burger::FilePNG::m_Palette[256]

private

Palette found in the image.

m_uChunkSize

uint32_t Burger::FilePNG::m_uChunkSize

private

Size of the current chunk in bytes.

m_uNextOffset

uintptr_t Burger::FilePNG::m_uNextOffset

private

Offset to the next chunk.

m_uPNGID

uint32_t Burger::FilePNG::m_uPNGID

private

Untouched ID of the current PNG chunk.

m_uStartOffset

uintptr_t Burger::FilePNG::m_uStartOffset

private

PNG file image chunk start offset.