Class PngImageHelper

java.lang.Object

com.itextpdf.io.image.PngImageHelper

class PngImageHelper
extends Object

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static class	PngImageHelper.PngParameters

Field Summary

Fields

Modifier and Type	Field	Description
static final String	cHRM	A PNG marker.
static final String	gAMA	A PNG marker.
static final String	iCCP	A PNG marker.
static final String	IDAT	A PNG marker.
static final String	IEND	A PNG marker.
static final String	IHDR	A PNG marker.
private static final String[]	intents
static final String	pHYs	A PNG marker.
static final String	PLTE	A PNG marker.
private static final int	PNG_FILTER_AVERAGE
private static final int	PNG_FILTER_NONE
private static final int	PNG_FILTER_PAETH
private static final int	PNG_FILTER_SUB
private static final int	PNG_FILTER_UP
static final int[]	PNGID	Some PNG specific values.
static final String	sRGB	A PNG marker.
private static final int	TRANSFERSIZE
static final String	tRNS	A PNG marker.

Constructor Summary

Constructors

Constructor	Description
PngImageHelper()

Method Summary

Modifier and Type	Method	Description
private static boolean	checkMarker(String s)
private static void	decodeAverageFilter(byte[] curr, byte[] prev, int count, int bpp)
private static void	decodeIdat(PngImageHelper.PngParameters png)
private static void	decodePaethFilter(byte[] curr, byte[] prev, int count, int bpp)
private static void	decodePass(int xOffset, int yOffset, int xStep, int yStep, int passWidth, int passHeight, PngImageHelper.PngParameters png)
private static void	decodeSubFilter(byte[] curr, int count, int bpp)
private static void	decodeUpFilter(byte[] curr, byte[] prev, int count)
private static int	getExpectedNumberOfColorComponents(PngImageHelper.PngParameters png)
static int	getInt(InputStream pngStream)	Gets an int from an InputStream.
private static int	getPixel(byte[] image, int x, int y, int bitDepth, int bytesPerRow)
private static int[]	getPixel(byte[] curr, PngImageHelper.PngParameters png)
static String	getString(InputStream pngStream)	Gets a String from an InputStream.
static int	getWord(InputStream pngStream)	Gets a word from an InputStream.
private static int	paethPredictor(int a, int b, int c)
static void	processImage(ImageData image)
private static void	processPixels(byte[] curr, int xOffset, int step, int y, int width, PngImageHelper.PngParameters png)
private static void	processPng(InputStream pngStream, PngImageHelper.PngParameters png)
private static void	readPng(InputStream pngStream, PngImageHelper.PngParameters png)
(package private) static void	setPixel(byte[] image, int[] data, int offset, int size, int x, int y, int bitDepth, int bytesPerRow)

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

PNGID

public static final int[] PNGID

Some PNG specific values.

IHDR

public static final String IHDR

A PNG marker.

See Also:

• Constant Field Values

PLTE

public static final String PLTE

A PNG marker.

See Also:

• Constant Field Values

IDAT

public static final String IDAT

A PNG marker.

See Also:

• Constant Field Values

IEND

public static final String IEND

A PNG marker.

See Also:

• Constant Field Values

tRNS

public static final String tRNS

A PNG marker.

See Also:

• Constant Field Values

pHYs

public static final String pHYs

A PNG marker.

See Also:

• Constant Field Values

gAMA

public static final String gAMA

A PNG marker.

See Also:

• Constant Field Values

cHRM

public static final String cHRM

A PNG marker.

See Also:

• Constant Field Values

sRGB

public static final String sRGB

A PNG marker.

See Also:

• Constant Field Values

iCCP

public static final String iCCP

A PNG marker.

See Also:

• Constant Field Values

TRANSFERSIZE

private static final int TRANSFERSIZE

See Also:

• Constant Field Values

PNG_FILTER_NONE

private static final int PNG_FILTER_NONE

See Also:

• Constant Field Values

PNG_FILTER_SUB

private static final int PNG_FILTER_SUB

See Also:

• Constant Field Values

PNG_FILTER_UP

private static final int PNG_FILTER_UP

See Also:

• Constant Field Values

PNG_FILTER_AVERAGE

private static final int PNG_FILTER_AVERAGE

See Also:

• Constant Field Values

PNG_FILTER_PAETH

private static final int PNG_FILTER_PAETH

See Also:

• Constant Field Values

intents

private static final String[] intents

Constructor Details

PngImageHelper

PngImageHelper()

Method Details

processImage

public static void processImage(ImageData image)

processPng

private static void processPng(InputStream pngStream,
 PngImageHelper.PngParameters png)
                        throws IOException

Throws:

IOException

getExpectedNumberOfColorComponents

private static int getExpectedNumberOfColorComponents(PngImageHelper.PngParameters png)

readPng

private static void readPng(InputStream pngStream,
 PngImageHelper.PngParameters png)
                     throws IOException

Throws:

IOException

checkMarker

private static boolean checkMarker(String s)

decodeIdat

private static void decodeIdat(PngImageHelper.PngParameters png)

decodePass

private static void decodePass(int xOffset,
 int yOffset,
 int xStep,
 int yStep,
 int passWidth,
 int passHeight,
 PngImageHelper.PngParameters png)

processPixels

private static void processPixels(byte[] curr,
 int xOffset,
 int step,
 int y,
 int width,
 PngImageHelper.PngParameters png)

getPixel

private static int getPixel(byte[] image,
 int x,
 int y,
 int bitDepth,
 int bytesPerRow)

setPixel

static void setPixel(byte[] image,
 int[] data,
 int offset,
 int size,
 int x,
 int y,
 int bitDepth,
 int bytesPerRow)

getPixel

private static int[] getPixel(byte[] curr,
 PngImageHelper.PngParameters png)

decodeSubFilter

private static void decodeSubFilter(byte[] curr,
 int count,
 int bpp)

decodeUpFilter

private static void decodeUpFilter(byte[] curr,
 byte[] prev,
 int count)

decodeAverageFilter

private static void decodeAverageFilter(byte[] curr,
 byte[] prev,
 int count,
 int bpp)

paethPredictor

private static int paethPredictor(int a,
 int b,
 int c)

decodePaethFilter

private static void decodePaethFilter(byte[] curr,
 byte[] prev,
 int count,
 int bpp)

getInt

public static int getInt(InputStream pngStream)
                  throws IOException

Gets an int from an InputStream.

Parameters:

pngStream - an InputStream

Returns:

the value of an int

Throws:

IOException

getWord

public static int getWord(InputStream pngStream)
                   throws IOException

Gets a word from an InputStream.

Parameters:

pngStream - an InputStream

Returns:

the value of an int

Throws:

IOException

getString

public static String getString(InputStream pngStream)
                        throws IOException

Gets a String from an InputStream.

Parameters:

pngStream - an InputStream

Returns:

the value of an int

Throws:

IOException