Class PNGEncodeParam

java.lang.Object
org.apache.xmlgraphics.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:
  • Field Details

    • INTENT_PERCEPTUAL

      public static final int INTENT_PERCEPTUAL
      Constant for use with the sRGB chunk.
      See Also:
    • INTENT_RELATIVE

      public static final int INTENT_RELATIVE
      Constant for use with the sRGB chunk.
      See Also:
    • INTENT_SATURATION

      public static final int INTENT_SATURATION
      Constant for use with the sRGB chunk.
      See Also:
    • INTENT_ABSOLUTE

      public static final int INTENT_ABSOLUTE
      Constant for use with the sRGB chunk.
      See Also:
    • PNG_FILTER_NONE

      public static final int PNG_FILTER_NONE
      Constant for use in filtering.
      See Also:
    • PNG_FILTER_SUB

      public static final int PNG_FILTER_SUB
      Constant for use in filtering.
      See Also:
    • PNG_FILTER_UP

      public static final int PNG_FILTER_UP
      Constant for use in filtering.
      See Also:
    • PNG_FILTER_AVERAGE

      public static final int PNG_FILTER_AVERAGE
      Constant for use in filtering.
      See Also:
    • PNG_FILTER_PAETH

      public static final int PNG_FILTER_PAETH
      Constant for use in filtering.
      See Also:
    • bitDepth

      protected int bitDepth
    • bitDepthSet

      protected boolean bitDepthSet
  • Constructor Details

    • PNGEncodeParam

      public PNGEncodeParam()
  • Method Details

    • 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 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.