org.apache.batik.ext.awt.image.codec.png
Class PNGEncodeParam

java.lang.Object
  extended by org.apache.batik.ext.awt.image.codec.png.PNGEncodeParam
All Implemented Interfaces:
Serializable, Cloneable, ImageDecodeParam, ImageEncodeParam
Direct Known Subclasses:
PNGEncodeParam.Gray, PNGEncodeParam.Palette, PNGEncodeParam.RGB

public abstract class PNGEncodeParam
extends Object
implements ImageEncodeParam

An instance of ImageEncodeParam for encoding images in the PNG format.

This class is not a committed part of the JAI API. It may be removed or changed in future releases of JAI.

See Also:
Serialized Form

Nested Class Summary
static class PNGEncodeParam.Gray
           
static class PNGEncodeParam.Palette
           
static class PNGEncodeParam.RGB
           
 
Field Summary
protected  int bitDepth
           
protected  boolean bitDepthSet
           
static int INTENT_ABSOLUTE
          Constant for use with the sRGB chunk.
static int INTENT_PERCEPTUAL
          Constant for use with the sRGB chunk.
static int INTENT_RELATIVE
          Constant for use with the sRGB chunk.
static int INTENT_SATURATION
          Constant for use with the sRGB chunk.
static int PNG_FILTER_AVERAGE
          Constant for use in filtering.
static int PNG_FILTER_NONE
          Constant for use in filtering.
static int PNG_FILTER_PAETH
          Constant for use in filtering.
static int PNG_FILTER_SUB
          Constant for use in filtering.
static int PNG_FILTER_UP
          Constant for use in filtering.
 
Constructor Summary
PNGEncodeParam()
           
 
Method Summary
 void addPrivateChunk(String type, byte[] data)
          Adds a private chunk, in binary form, to the list of chunks to be stored with this image.
 int filterRow(byte[] currRow, byte[] prevRow, byte[][] scratchRows, int bytesPerRow, int bytesPerPixel)
          Performs filtering on a row of an image.
 int getBitDepth()
          Returns the desired bit depth for a grayscale image.
 float[] getChromaticity()
          Returns the white point and primary chromaticities in CIE (x, y) space.
 String[] getCompressedText()
          Returns the text strings to be stored in compressed form with this image as an array of Strings.
static PNGEncodeParam getDefaultEncodeParam(RenderedImage im)
          Returns an instance of PNGEncodeParam.Palette, PNGEncodeParam.Gray, or PNGEncodeParam.RGB appropriate for encoding the given image.
 float getGamma()
          Returns the file gamma value for the image.
 byte[] getICCProfileData()
          Returns the ICC profile data to be stored with this image.
 boolean getInterlacing()
          Returns true if Adam7 interlacing will be used.
 Date getModificationTime()
          Returns the modification time to be stored with this image.
 int getNumPrivateChunks()
          Returns the number of private chunks to be written to the output file.
 int[] getPaletteHistogram()
          Returns the palette histogram to be stored with this image.
 int[] getPhysicalDimension()
          Returns the physical dimension information to be stored with this image.
 byte[] getPrivateChunkData(int index)
          Returns the data associated of the private chunk at a given index, as an array of bytes.
 String getPrivateChunkType(int index)
          Returns the type of the private chunk at a given index, as a 4-character String.
 int[] getSignificantBits()
          Returns the number of significant bits for each band of the image.
 int getSRGBIntent()
          Returns the sRGB rendering intent to be stored with this image.
 PNGSuggestedPaletteEntry[] getSuggestedPalette()
          Returns the suggested palette information to be stored with this image.
 String[] getText()
          Returns the text strings to be stored in uncompressed form with this image as an array of Strings.
 boolean isBackgroundSet()
          Returns true if a 'bKGD' chunk will be output.
 boolean isChromaticitySet()
          Returns true if a 'cHRM' chunk will be output.
 boolean isCompressedTextSet()
          Returns true if a 'zTXT' chunk will be output.
 boolean isGammaSet()
          Returns true if a 'gAMA' chunk will be output.
 boolean isICCProfileDataSet()
          Returns true if a 'iCCP' chunk will be output.
 boolean isModificationTimeSet()
          Returns true if a 'tIME' chunk will be output.
 boolean isPaletteHistogramSet()
          Returns true if a 'hIST' chunk will be output.
 boolean isPhysicalDimensionSet()
          Returns true if a 'pHYS' chunk will be output.
 boolean isSignificantBitsSet()
          Returns true if an 'sBIT' chunk will be output.
 boolean isSRGBIntentSet()
          Returns true if an 'sRGB' chunk will be output.
 boolean isSuggestedPaletteSet()
          Returns true if a 'sPLT' chunk will be output.
 boolean isTextSet()
          Returns true if a 'tEXt' chunk will be output.
 boolean isTransparencySet()
          Returns true if a 'tRNS' chunk will be output.
static int paethPredictor(int a, int b, int c)
          The Paeth predictor routine used in PNG encoding.
 void removeAllPrivateChunks()
          Remove all private chunks associated with this parameter instance.
 void removeUnsafeToCopyPrivateChunks()
          Remove all private chunks associated with this parameter instance whose 'safe-to-copy' bit is not set.
abstract  void setBitDepth(int bitDepth)
          Sets the desired bit depth of an image.
 void setChromaticity(float[] chromaticity)
          Sets the white point and primary chromaticities in CIE (x, y) space.
 void setChromaticity(float whitePointX, float whitePointY, float redX, float redY, float greenX, float greenY, float blueX, float blueY)
          A convenience method that calls the array version.
 void setCompressedText(String[] text)
          Sets the text strings to be stored in compressed form with this image.
 void setGamma(float gamma)
          Sets the file gamma value for the image.
 void setICCProfileData(byte[] ICCProfileData)
          Sets the ICC profile data to be stored with this image.
 void setInterlacing(boolean useInterlacing)
          Turns Adam7 interlacing on or off.
 void setModificationTime(Date modificationTime)
          Sets the modification time, as a Date, to be stored with this image.
 void setPaletteHistogram(int[] paletteHistogram)
          Sets the palette histogram to be stored with this image.
 void setPhysicalDimension(int[] physicalDimension)
          Sets the physical dimension information to be stored with this image.
 void setPhysicalDimension(int xPixelsPerUnit, int yPixelsPerUnit, int unitSpecifier)
          A convenience method that calls the array version.
 void setSignificantBits(int[] significantBits)
          Sets the number of significant bits for each band of the image.
 void setSRGBIntent(int SRGBIntent)
          Sets the sRGB rendering intent to be stored with this image.
 void setSuggestedPalette(PNGSuggestedPaletteEntry[] palette)
          Sets the suggested palette information to be stored with this image.
 void setText(String[] text)
          Sets the textual data to be stored in uncompressed form with this image.
 void unsetBackground()
          Suppresses the 'bKGD' chunk from being output.
 void unsetBitDepth()
          Suppresses the setting of the bit depth of a grayscale image.
 void unsetChromaticity()
          Suppresses the 'cHRM' chunk from being output.
 void unsetCompressedText()
          Suppresses the 'zTXt' chunk from being output.
 void unsetGamma()
          Suppresses the 'gAMA' chunk from being output.
 void unsetICCProfileData()
          Suppresses the 'iCCP' chunk from being output.
 void unsetModificationTime()
          Suppresses the 'tIME' chunk from being output.
 void unsetPaletteHistogram()
          Suppresses the 'hIST' chunk from being output.
 void unsetPhysicalDimension()
          Suppresses the 'pHYS' chunk from being output.
 void unsetSignificantBits()
          Suppresses the 'sBIT' chunk from being output.
 void unsetSRGBIntent()
          Suppresses the 'sRGB' chunk from being output.
 void unsetSuggestedPalette()
          Suppresses the 'sPLT' chunk from being output.
 void unsetText()
          Suppresses the 'tEXt' chunk from being output.
 void unsetTransparency()
          Suppresses the 'tRNS' chunk from being output.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

INTENT_PERCEPTUAL

public static final int INTENT_PERCEPTUAL
Constant for use with the sRGB chunk.

See Also:
Constant Field Values

INTENT_RELATIVE

public static final int INTENT_RELATIVE
Constant for use with the sRGB chunk.

See Also:
Constant Field Values

INTENT_SATURATION

public static final int INTENT_SATURATION
Constant for use with the sRGB chunk.

See Also:
Constant Field Values

INTENT_ABSOLUTE

public static final int INTENT_ABSOLUTE
Constant for use with the sRGB chunk.

See Also:
Constant Field Values

PNG_FILTER_NONE

public static final int PNG_FILTER_NONE
Constant for use in filtering.

See Also:
Constant Field Values

PNG_FILTER_SUB

public static final int PNG_FILTER_SUB
Constant for use in filtering.

See Also:
Constant Field Values

PNG_FILTER_UP

public static final int PNG_FILTER_UP
Constant for use in filtering.

See Also:
Constant Field Values

PNG_FILTER_AVERAGE

public static final int PNG_FILTER_AVERAGE
Constant for use in filtering.

See Also:
Constant Field Values

PNG_FILTER_PAETH

public static final int PNG_FILTER_PAETH
Constant for use in filtering.

See Also:
Constant Field Values

bitDepth

protected int bitDepth

bitDepthSet

protected boolean bitDepthSet
Constructor Detail

PNGEncodeParam

public PNGEncodeParam()
Method Detail

getDefaultEncodeParam

public static PNGEncodeParam getDefaultEncodeParam(RenderedImage im)
Returns an instance of PNGEncodeParam.Palette, PNGEncodeParam.Gray, or PNGEncodeParam.RGB appropriate for encoding the given image.

If the image has an IndexColorModel, an instance of PNGEncodeParam.Palette is returned. Otherwise, if the image has 1 or 2 bands an instance of PNGEncodeParam.Gray is returned. In all other cases an instance of PNGEncodeParam.RGB is returned.

Note that this method does not provide any guarantee that the given image will be successfully encoded by the PNG encoder, as it only performs a very superficial analysis of the image structure.


setBitDepth

public abstract void setBitDepth(int bitDepth)
Sets the desired bit depth of an image.


getBitDepth

public int getBitDepth()
Returns the desired bit depth for a grayscale image.

If the bit depth has not previously been set, or has been unset, an IllegalStateException will be thrown.

Throws:
IllegalStateException - if the bit depth is not set.

unsetBitDepth

public void unsetBitDepth()
Suppresses the setting of the bit depth of a grayscale image. The depth of the encoded image will be inferred from the source image bit depth, rounded up to the next power of 2 between 1 and 16.


setInterlacing

public void setInterlacing(boolean useInterlacing)
Turns Adam7 interlacing on or off.


getInterlacing

public boolean getInterlacing()
Returns true if Adam7 interlacing will be used.


unsetBackground

public void unsetBackground()
Suppresses the 'bKGD' chunk from being output. For API compatibility with JAI 1.0, the superclass defines this method to throw a RuntimeException; accordingly, subclasses must provide their own implementations.


isBackgroundSet

public boolean isBackgroundSet()
Returns true if a 'bKGD' chunk will be output. For API compatibility with JAI 1.0, the superclass defines this method to throw a RuntimeException; accordingly, subclasses must provide their own implementations.


setChromaticity

public void setChromaticity(float[] chromaticity)
Sets the white point and primary chromaticities in CIE (x, y) space.

The chromaticity parameter should be a float array of length 8 containing the white point X and Y, red X and Y, green X and Y, and blue X and Y values in order.

The 'cHRM' chunk will encode this information.


setChromaticity

public void setChromaticity(float whitePointX,
                            float whitePointY,
                            float redX,
                            float redY,
                            float greenX,
                            float greenY,
                            float blueX,
                            float blueY)
A convenience method that calls the array version.


getChromaticity

public float[] getChromaticity()
Returns the white point and primary chromaticities in CIE (x, y) space.

See the documentation for the setChromaticity method for the format of the returned data.

If the chromaticity has not previously been set, or has been unset, an IllegalStateException will be thrown.

Throws:
IllegalStateException - if the chromaticity is not set.

unsetChromaticity

public void unsetChromaticity()
Suppresses the 'cHRM' chunk from being output.


isChromaticitySet

public boolean isChromaticitySet()
Returns true if a 'cHRM' chunk will be output.


setGamma

public void setGamma(float gamma)
Sets the file gamma value for the image.

The 'gAMA' chunk will encode this information.


getGamma

public float getGamma()
Returns the file gamma value for the image.

If the file gamma has not previously been set, or has been unset, an IllegalStateException will be thrown.

Throws:
IllegalStateException - if the gamma is not set.

unsetGamma

public void unsetGamma()
Suppresses the 'gAMA' chunk from being output.


isGammaSet

public boolean isGammaSet()
Returns true if a 'gAMA' chunk will be output.


setPaletteHistogram

public void setPaletteHistogram(int[] paletteHistogram)
Sets the palette histogram to be stored with this image. The histogram consists of an array of integers, one per palette entry.

The 'hIST' chunk will encode this information.


getPaletteHistogram

public int[] getPaletteHistogram()
Returns the palette histogram to be stored with this image.

If the histogram has not previously been set, or has been unset, an IllegalStateException will be thrown.

Throws:
IllegalStateException - if the histogram is not set.

unsetPaletteHistogram

public void unsetPaletteHistogram()
Suppresses the 'hIST' chunk from being output.


isPaletteHistogramSet

public boolean isPaletteHistogramSet()
Returns true if a 'hIST' chunk will be output.


setICCProfileData

public void setICCProfileData(byte[] ICCProfileData)
Sets the ICC profile data to be stored with this image. The profile is represented in raw binary form.

The 'iCCP' chunk will encode this information.


getICCProfileData

public byte[] getICCProfileData()
Returns the ICC profile data to be stored with this image.

If the ICC profile has not previously been set, or has been unset, an IllegalStateException will be thrown.

Throws:
IllegalStateException - if the ICC profile is not set.

unsetICCProfileData

public void unsetICCProfileData()
Suppresses the 'iCCP' chunk from being output.


isICCProfileDataSet

public boolean isICCProfileDataSet()
Returns true if a 'iCCP' chunk will be output.


setPhysicalDimension

public void setPhysicalDimension(int[] physicalDimension)
Sets the physical dimension information to be stored with this image. The physicalDimension parameter should be a 3-entry array containing the number of pixels per unit in the X direction, the number of pixels per unit in the Y direction, and the unit specifier (0 = unknown, 1 = meters).

The 'pHYS' chunk will encode this information.


setPhysicalDimension

public void setPhysicalDimension(int xPixelsPerUnit,
                                 int yPixelsPerUnit,
                                 int unitSpecifier)
A convenience method that calls the array version.


getPhysicalDimension

public int[] getPhysicalDimension()
Returns the physical dimension information to be stored with this image.

If the physical dimension information has not previously been set, or has been unset, an IllegalStateException will be thrown.

Throws:
IllegalStateException - if the physical dimension information is not set.

unsetPhysicalDimension

public void unsetPhysicalDimension()
Suppresses the 'pHYS' chunk from being output.


isPhysicalDimensionSet

public boolean isPhysicalDimensionSet()
Returns true if a 'pHYS' chunk will be output.


setSuggestedPalette

public void setSuggestedPalette(PNGSuggestedPaletteEntry[] palette)
Sets the suggested palette information to be stored with this image. The information is passed to this method as an array of PNGSuggestedPaletteEntry objects.

The 'sPLT' chunk will encode this information.


getSuggestedPalette

public PNGSuggestedPaletteEntry[] getSuggestedPalette()
Returns the suggested palette information to be stored with this image.

If the suggested palette information has not previously been set, or has been unset, an IllegalStateException will be thrown.

Throws:
IllegalStateException - if the suggested palette information is not set.

unsetSuggestedPalette

public void unsetSuggestedPalette()
Suppresses the 'sPLT' chunk from being output.


isSuggestedPaletteSet

public boolean isSuggestedPaletteSet()
Returns true if a 'sPLT' chunk will be output.


setSignificantBits

public void setSignificantBits(int[] significantBits)
Sets the number of significant bits for each band of the image.

The number of entries in the significantBits array must be equal to the number of output bands in the image: 1 for a gray image, 2 for gray+alpha, 3 for index or truecolor, and 4 for truecolor+alpha.

The 'sBIT' chunk will encode this information.


getSignificantBits

public int[] getSignificantBits()
Returns the number of significant bits for each band of the image.

If the significant bits values have not previously been set, or have been unset, an IllegalStateException will be thrown.

Throws:
IllegalStateException - if the significant bits values are not set.

unsetSignificantBits

public void unsetSignificantBits()
Suppresses the 'sBIT' chunk from being output.


isSignificantBitsSet

public boolean isSignificantBitsSet()
Returns true if an 'sBIT' chunk will be output.


setSRGBIntent

public void setSRGBIntent(int SRGBIntent)
Sets the sRGB rendering intent to be stored with this image. The legal values are 0 = Perceptual, 1 = Relative Colorimetric, 2 = Saturation, and 3 = Absolute Colorimetric. Refer to the PNG specification for information on these values.

The 'sRGB' chunk will encode this information.


getSRGBIntent

public int getSRGBIntent()
Returns the sRGB rendering intent to be stored with this image.

If the sRGB intent has not previously been set, or has been unset, an IllegalStateException will be thrown.

Throws:
IllegalStateException - if the sRGB intent is not set.

unsetSRGBIntent

public void unsetSRGBIntent()
Suppresses the 'sRGB' chunk from being output.


isSRGBIntentSet

public boolean isSRGBIntentSet()
Returns true if an 'sRGB' chunk will be output.


setText

public void setText(String[] text)
Sets the textual data to be stored in uncompressed form with this image. The data is passed to this method as an array of Strings.

The 'tEXt' chunk will encode this information.


getText

public String[] getText()
Returns the text strings to be stored in uncompressed form with this image as an array of Strings.

If the text strings have not previously been set, or have been unset, an IllegalStateException will be thrown.

Throws:
IllegalStateException - if the text strings are not set.

unsetText

public void unsetText()
Suppresses the 'tEXt' chunk from being output.


isTextSet

public boolean isTextSet()
Returns true if a 'tEXt' chunk will be output.


setModificationTime

public void setModificationTime(Date modificationTime)
Sets the modification time, as a Date, to be stored with this image. The internal storage format will use UTC regardless of how the modificationTime parameter was created.

The 'tIME' chunk will encode this information.


getModificationTime

public Date getModificationTime()
Returns the modification time to be stored with this image.

If the bit depth has not previously been set, or has been unset, an IllegalStateException will be thrown.

Throws:
IllegalStateException - if the bit depth is not set.

unsetModificationTime

public void unsetModificationTime()
Suppresses the 'tIME' chunk from being output.


isModificationTimeSet

public boolean isModificationTimeSet()
Returns true if a 'tIME' chunk will be output.


unsetTransparency

public void unsetTransparency()
Suppresses the 'tRNS' chunk from being output.


isTransparencySet

public boolean isTransparencySet()
Returns true if a 'tRNS' chunk will be output.


setCompressedText

public void setCompressedText(String[] text)
Sets the text strings to be stored in compressed form with this image. The data is passed to this method as an array of Strings.

The 'zTXt' chunk will encode this information.


getCompressedText

public String[] getCompressedText()
Returns the text strings to be stored in compressed form with this image as an array of Strings.

If the compressed text strings have not previously been set, or have been unset, an IllegalStateException will be thrown.

Throws:
IllegalStateException - if the compressed text strings are not set.

unsetCompressedText

public void unsetCompressedText()
Suppresses the 'zTXt' chunk from being output.


isCompressedTextSet

public boolean isCompressedTextSet()
Returns true if a 'zTXT' chunk will be output.


addPrivateChunk

public void addPrivateChunk(String type,
                            byte[] data)
Adds a private chunk, in binary form, to the list of chunks to be stored with this image.

Parameters:
type - a 4-character String giving the chunk type name.
data - an array of bytes containing the chunk data.

getNumPrivateChunks

public int getNumPrivateChunks()
Returns the number of private chunks to be written to the output file.


getPrivateChunkType

public String getPrivateChunkType(int index)
Returns the type of the private chunk at a given index, as a 4-character String. The index must be smaller than the return value of getNumPrivateChunks.


getPrivateChunkData

public byte[] getPrivateChunkData(int index)
Returns the data associated of the private chunk at a given index, as an array of bytes. The index must be smaller than the return value of getNumPrivateChunks.


removeUnsafeToCopyPrivateChunks

public void removeUnsafeToCopyPrivateChunks()
Remove all private chunks associated with this parameter instance whose 'safe-to-copy' bit is not set. This may be advisable when transcoding PNG images.


removeAllPrivateChunks

public void removeAllPrivateChunks()
Remove all private chunks associated with this parameter instance.


paethPredictor

public static final int paethPredictor(int a,
                                       int b,
                                       int c)
The Paeth predictor routine used in PNG encoding. This routine is included as a convenience to subclasses that override the filterRow method.


filterRow

public int filterRow(byte[] currRow,
                     byte[] prevRow,
                     byte[][] scratchRows,
                     int bytesPerRow,
                     int bytesPerPixel)
Performs filtering on a row of an image. This method may be overridden in order to provide a custom algorithm for choosing the filter type for a given row.

The method is supplied with the current and previous rows of the image. For the first row of the image, or of an interlacing pass, the previous row array will be filled with zeros as required by the PNG specification.

The method is also supplied with five scratch arrays. These arrays may be used within the method for any purpose. At method exit, the array at the index given by the return value of the method should contain the filtered data. The return value will also be used as the filter type.

The default implementation of the method performs a trial encoding with each of the filter types, and computes the sum of absolute values of the differences between the raw bytes of the current row and the predicted values. The index of the filter producing the smallest result is returned.

As an example, to perform only 'sub' filtering, this method could be implemented (non-optimally) as follows:

 for (int i = bytesPerPixel; i < bytesPerRow + bytesPerPixel; i++) {
     int curr = currRow[i] & 0xff;
     int left = currRow[i - bytesPerPixel] & 0xff;
     scratchRow[PNG_FILTER_SUB][i] = (byte)(curr - left);
 }
 return PNG_FILTER_SUB;
 

Parameters:
currRow - The current row as an array of bytes of length at least bytesPerRow + bytesPerPixel. The pixel data starts at index bytesPerPixel; the initial bytesPerPixel bytes are zero.
prevRow - The current row as an array of bytes The pixel data starts at index bytesPerPixel; the initial bytesPerPixel bytes are zero.
scratchRows - An array of 5 byte arrays of length at least bytesPerRow + bytesPerPixel, useable to hold temporary results. The filtered row will be returned as one of the entries of this array. The returned filtered data should start at index bytesPerPixel; The initial bytesPerPixel bytes are not used.
bytesPerRow - The number of bytes in the image row. This value will always be greater than 0.
bytesPerPixel - The number of bytes representing a single pixel, rounded up to an integer. This is the 'bpp' parameter described in the PNG specification.
Returns:
The filter type to be used. The entry of scratchRows[] at this index holds the filtered data.


Copyright © 2008 Apache Software Foundation. All Rights Reserved.