IlvPNGStreamer Class Reference

Bitmap streamer class. More...

#include <ilviews/bitmaps/png.h>

Inheritance diagram for IlvPNGStreamer:

List of all members.

Public Member Functions
	IlvPNGStreamer ()
	Constructor.
IlBoolean	canRead () const
	Indicates that the instance can read from a stream.
IlBoolean	canWrite () const
	Indicates that the instance can write to a stream.
IlBoolean	checkSignature (const IlUChar *data, IlUInt size)
	Checks the signature of the input stream.
IlUInt	getAlphaLevel () const
	Gets the alpha level of the PNG streamer.
IlUInt	getCompressionLevel () const
	Gets the compression level of the generated PNG stream.
IlUShort	getIndexedColors () const
	Returns the number of colors to quantize to.
IlBoolean	hasInterlace () const
	Gets whether the generated PNG stream is interlaced.
IlBoolean	isIndexed () const
IlvBitmapData *	read (istream &stream)
	Reads a PNG image from a stream.
void	setAlphaLevel (IlUInt level)
	Sets the alpha level for the PNG stream.
void	setCompressionLevel (IlUInt level)
	Sets the compression level of the generated PNG stream.
void	setIndexed (IlBoolean indexed, IlUShort numcols=256)
	Sets whether the generated PNG stream is indexed.
void	setInterlace (IlBoolean interlace)
	Sets whether the generated PNG stream is interlaced.
IlBoolean	write (IlvBitmapData *data, ostream &stream)
	Writes an IlvBitmapData to a PNG stream.

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Detailed Description

Bitmap streamer class.

Library: display

This streamer provides methods to deal with a stream containing a PNG image. It supports reading from all PNG streams. It handles transparent images by mapping alpha values greater than 50 to opaque and others to transparent.
This streamer can read and write.
When writing, it is possible to force indexed output using a specified number of colors. When reading or writing interlaced images, callbacks will be called at each pass. When reading or writing non-interlaced images, callbacks will be called at each scanline.

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Member Function Documentation

IlBoolean IlvPNGStreamer::canRead

(

)

const [virtual]

Indicates that the instance can read from a stream.

Returns:

IlTrue.

Reimplemented from IlvBitmapStreamer.

IlBoolean IlvPNGStreamer::canWrite

(

)

const [virtual]

Indicates that the instance can write to a stream.

Returns:

IlTrue.

Reimplemented from IlvBitmapStreamer.

IlBoolean IlvPNGStreamer::checkSignature	(	const IlUChar *	data,
		IlUInt	size
	)			[virtual]

Checks the signature of the input stream.

Parameters:

	data	The data containing the signature of the stream.
	size	The size of the data containing the signature.

Returns:

IlTrue if the data contains a PNG signature.

Implements IlvBitmapStreamer.

IlUInt IlvPNGStreamer::getAlphaLevel

(

)

const

Gets the alpha level of the PNG streamer.

Returns:

The alpha level.

IlUInt IlvPNGStreamer::getCompressionLevel

(

)

const

Gets the compression level of the generated PNG stream.

Returns:

The compression level.

IlUShort IlvPNGStreamer::getIndexedColors

(

)

const

Returns the number of colors to quantize to.

Returns:

The number of colors.

IlBoolean IlvPNGStreamer::hasInterlace

(

)

const

Gets whether the generated PNG stream is interlaced.

Returns:

IlTrue if the generated PNG stream is interlaced.

IlBoolean IlvPNGStreamer::isIndexed

(

)

const

Gets whether the generated PNG stream is indexed .

Returns:

IlTrue if the generated PNG stream is indexed.

IlvBitmapData* IlvPNGStreamer::read

(

istream &

stream

)

[virtual]

Reads a PNG image from a stream.

Parameters:

stream

The stream to read from.

Returns:

An instance of IlvBitmapData.

Reimplemented from IlvBitmapStreamer.

void IlvPNGStreamer::setAlphaLevel

(

IlUInt

level

)

Sets the alpha level for the PNG stream.

Alpha levels greater than the given argument are converted to a fully opaque value while alpha levels smaller than the given argument are converted to a fully transparent value.

Parameters:

level

The alpha level.

void IlvPNGStreamer::setCompressionLevel

(

IlUInt

level

)

Sets the compression level of the generated PNG stream.

Parameters:

level

The compression level: 0: No compression. 1: Best speed compression 2: Best compression.

void IlvPNGStreamer::setIndexed	(	IlBoolean	indexed,
		IlUShort	numcols = 256
	)

Sets whether the generated PNG stream is indexed.

Parameters:

	indexed	IlTrue if the stream is generated in indexed mode.
	numcols	The number of desired colors if quantization is performed.

void IlvPNGStreamer::setInterlace

(

IlBoolean

interlace

)

Sets whether the generated PNG stream is interlaced.

Parameters:

interlace

IlTrue if the stream is interlaced.

IlBoolean IlvPNGStreamer::write	(	IlvBitmapData *	data,
		ostream &	stream
	)			[virtual]

Writes an IlvBitmapData to a PNG stream.

Parameters:

	data	The bitmap data to write.
	stream	The stream to write to.

Returns:

IlTrue if the bitmap data has been written.

Reimplemented from IlvBitmapStreamer.