Hjg.Pngcs.PngWriter Class Reference

Writes a PNG image, line by line. More...

Public Member Functions
	PngWriter (Stream outputStream, ImageInfo imgInfo)
	Constructs a PngWriter from a outputStream, with no filename information
	PngWriter (Stream outputStream, ImageInfo imgInfo, String filename)
	Constructs a PngWriter from a outputStream, with optional filename or description
void	CopyChunksFirst (PngReader reader, int copy_mask)
void	CopyChunksLast (PngReader reader, int copy_mask)
double	ComputeCompressionRatio ()
	Computes compressed size/raw size, approximate
void	End ()
	Finalizes the image creation and closes the file stream.
String	GetFilename ()
	Filename or description, from the optional constructor argument.
void	WriteRow (ImageLine imgline, int rownumber)
	this uses the row number from the imageline!
void	WriteRow (int[] newrow)
void	WriteRow (int[] newrow, int rown)
void	WriteRowInt (int[] newrow, int rown)
	Writes a full image row.
void	WriteRowByte (byte[] newrow, int rown)
void	WriteRowsInt (int[][] image)
void	WriteRowsByte (byte[][] image)
PngMetadata	GetMetadata ()
ChunksListForWrite	GetChunksList ()
void	SetFilterType (FilterType filterType)
	Sets internal prediction filter type, or strategy to choose it.
bool	IsUnpackedMode ()
void	SetUseUnPackedMode (bool useUnpackedMode)

Public Attributes
readonly ImageInfo	ImgInfo
	Basic image info, inmutable

Protected Member Functions
void	encodeRowFromByte (byte[] row)
void	encodeRowFromInt (int[] row)

Protected Attributes
readonly String	filename
	filename, or description - merely informative, can be empty
byte[]	rowb
	raw current row, as array of bytes,counting from 1 (index 0 is reserved for filter type)
byte[]	rowbprev
	previuos raw row
byte[]	rowbfilter
	raw current row, after filtered

Properties
EDeflateCompressStrategy	CompressionStrategy [get, set]
int	CompLevel [get, set]
	zip compression level (0 - 9)
bool	ShouldCloseStream [get, set]
	true: closes stream after ending write
int	IdatMaxSize [get, set]
	Maximum size of IDAT chunks
int	CurrentChunkGroup [get, set]
	number of chunk group (0-6) last writen, or currently writing

Detailed Description

Writes a PNG image, line by line.

Constructor & Destructor Documentation

Hjg.Pngcs.PngWriter.PngWriter	(	Stream	outputStream,
		ImageInfo	imgInfo
	)

Constructs a PngWriter from a outputStream, with no filename information

Parameters

outputStream
imgInfo

Hjg.Pngcs.PngWriter.PngWriter	(	Stream	outputStream,
		ImageInfo	imgInfo,
		String	filename
	)

Constructs a PngWriter from a outputStream, with optional filename or description

After construction nothing is writen yet. You still can set some parameters (compression, filters) and queue chunks before start writing the pixels.

See also FileHelper.createPngWriter()

Parameters

outputStream	Opened stream for binary writing
imgInfo	Basic image parameters
filename	Optional, can be the filename or a description.

Member Function Documentation

void Hjg.Pngcs.PngWriter.encodeRowFromByte ( byte[]  row )

protected

void Hjg.Pngcs.PngWriter.encodeRowFromInt ( int[]  row )

protected

void Hjg.Pngcs.PngWriter.CopyChunksFirst	(	PngReader	reader,
		int	copy_mask
	)

void Hjg.Pngcs.PngWriter.CopyChunksLast	(	PngReader	reader,
		int	copy_mask
	)

double Hjg.Pngcs.PngWriter.ComputeCompressionRatio

(

)

Computes compressed size/raw size, approximate

Actually: compressed size = total size of IDAT data , raw size = uncompressed pixel bytes = rows * (bytesPerRow + 1)

Returns

void Hjg.Pngcs.PngWriter.End

(

)

Finalizes the image creation and closes the file stream.

This MUST be called after writing the lines.

String Hjg.Pngcs.PngWriter.GetFilename

(

)

Filename or description, from the optional constructor argument.

Returns

void Hjg.Pngcs.PngWriter.WriteRow	(	ImageLine	imgline,
		int	rownumber
	)

this uses the row number from the imageline!

void Hjg.Pngcs.PngWriter.WriteRow

(

int[]

newrow

)

void Hjg.Pngcs.PngWriter.WriteRow	(	int[]	newrow,
		int	rown
	)

void Hjg.Pngcs.PngWriter.WriteRowInt	(	int[]	newrow,
		int	rown
	)

Writes a full image row.

This must be called sequentially from n=0 to n=rows-1 One integer per sample , in the natural order: R G B R G B ... (or R G B A R G B A... if has alpha) The values should be between 0 and 255 for 8 bitspc images, and between 0- 65535 form 16 bitspc images (this applies also to the alpha channel if present) The array can be reused.

Parameters

newrow	Array of pixel values
rown	Number of row, from 0 (top) to rows-1 (bottom)

void Hjg.Pngcs.PngWriter.WriteRowByte	(	byte[]	newrow,
		int	rown
	)

void Hjg.Pngcs.PngWriter.WriteRowsInt

(

int

image[][]

)

Writes all the pixels, calling writeRowInt() for each image row

void Hjg.Pngcs.PngWriter.WriteRowsByte

(

byte

image[][]

)

Writes all the pixels, calling writeRowByte() for each image row

PngMetadata Hjg.Pngcs.PngWriter.GetMetadata

(

)

ChunksListForWrite Hjg.Pngcs.PngWriter.GetChunksList

(

)

void Hjg.Pngcs.PngWriter.SetFilterType

(

FilterType

filterType

)

Sets internal prediction filter type, or strategy to choose it.

This must be called just after constructor, before starting writing.

Recommended values: DEFAULT (default) or AGGRESIVE

Parameters

filterType

One of the five prediction types or strategy to choose it

bool Hjg.Pngcs.PngWriter.IsUnpackedMode

(

)

void Hjg.Pngcs.PngWriter.SetUseUnPackedMode

(

bool

useUnpackedMode

)

Member Data Documentation

readonly ImageInfo Hjg.Pngcs.PngWriter.ImgInfo

Basic image info, inmutable

readonly String Hjg.Pngcs.PngWriter.filename

protected

filename, or description - merely informative, can be empty

byte [] Hjg.Pngcs.PngWriter.rowb

protected

raw current row, as array of bytes,counting from 1 (index 0 is reserved for filter type)

byte [] Hjg.Pngcs.PngWriter.rowbprev

protected

previuos raw row

byte [] Hjg.Pngcs.PngWriter.rowbfilter

protected

raw current row, after filtered

Property Documentation

EDeflateCompressStrategy Hjg.Pngcs.PngWriter.CompressionStrategy

getset

Deflate algortithm compression strategy

int Hjg.Pngcs.PngWriter.CompLevel

getset

zip compression level (0 - 9)

default:6

9 is the maximum compression

bool Hjg.Pngcs.PngWriter.ShouldCloseStream

getset

true: closes stream after ending write

int Hjg.Pngcs.PngWriter.IdatMaxSize

getset

Maximum size of IDAT chunks

0=use default (PngIDatChunkOutputStream 32768)

int Hjg.Pngcs.PngWriter.CurrentChunkGroup

getset

number of chunk group (0-6) last writen, or currently writing

see ChunksList.CHUNK_GROUP_NNN