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/* $Id: mxPngEncodeParam.java,v 1.5 2010/08/09 16:41:04 david Exp $
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this work for additional information regarding copyright ownership.
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*/
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* Copyright (c) 2001 Sun Microsystems, Inc. All Rights Reserved.
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* modification, are permitted provided that the following conditions are met:
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package com.mxgraph.util.png;
import java.awt.image.ColorModel;
import java.awt.image.IndexColorModel;
import java.awt.image.RenderedImage;
import java.awt.image.SampleModel;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
/**
* 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.
*
* @version $Id: mxPngEncodeParam.java,v 1.5 2010/08/09 16:41:04 david Exp $
*/
public abstract class mxPngEncodeParam
{
/** Constant for use with the sRGB chunk. */
public static final int INTENT_PERCEPTUAL = 0;
/** Constant for use with the sRGB chunk. */
public static final int INTENT_RELATIVE = 1;
/** Constant for use with the sRGB chunk. */
public static final int INTENT_SATURATION = 2;
/** Constant for use with the sRGB chunk. */
public static final int INTENT_ABSOLUTE = 3;
/** Constant for use in filtering. */
public static final int PNG_FILTER_NONE = 0;
/** Constant for use in filtering. */
public static final int PNG_FILTER_SUB = 1;
/** Constant for use in filtering. */
public static final int PNG_FILTER_UP = 2;
/** Constant for use in filtering. */
public static final int PNG_FILTER_AVERAGE = 3;
/** Constant for use in filtering. */
public static final int PNG_FILTER_PAETH = 4;
/**
* 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.
*/
public static mxPngEncodeParam getDefaultEncodeParam(RenderedImage im)
{
ColorModel colorModel = im.getColorModel();
if (colorModel instanceof IndexColorModel)
{
return new mxPngEncodeParam.Palette();
}
SampleModel sampleModel = im.getSampleModel();
int numBands = sampleModel.getNumBands();
if (numBands == 1 || numBands == 2)
{
return new mxPngEncodeParam.Gray();
}
else
{
return new mxPngEncodeParam.RGB();
}
}
public static class Palette extends mxPngEncodeParam
{
/** Constructs an instance of PNGEncodeParam.Palette. */
public Palette()
{
}
// bKGD chunk
private boolean backgroundSet = false;
/**
* Suppresses the 'bKGD' chunk from being output.
*/
public void unsetBackground()
{
backgroundSet = false;
}
/**
* Returns true if a 'bKGD' chunk will be output.
*/
public boolean isBackgroundSet()
{
return backgroundSet;
}
/**
* Sets the desired bit depth for a palette image. The bit
* depth must be one of 1, 2, 4, or 8, or else an
* IllegalArgumentException will be thrown.
*/
public void setBitDepth(int bitDepth)
{
if (bitDepth != 1 && bitDepth != 2 && bitDepth != 4
&& bitDepth != 8)
{
throw new IllegalArgumentException("PNGEncodeParam2");
}
this.bitDepth = bitDepth;
bitDepthSet = true;
}
// PLTE chunk
private int[] palette = null;
private boolean paletteSet = false;
/**
* Sets the RGB palette of the image to be encoded.
* The rgb parameter contains alternating
* R, G, B values for each color index used in the image.
* The number of elements must be a multiple of 3 between
* 3 and 3*256.
*
*
The 'PLTE' chunk will encode this information.
*
* @param rgb An array of ints.
*/
public void setPalette(int[] rgb)
{
if (rgb.length < 1 * 3 || rgb.length > 256 * 3)
{
throw new IllegalArgumentException("PNGEncodeParam0");
}
if ((rgb.length % 3) != 0)
{
throw new IllegalArgumentException("PNGEncodeParam1");
}
palette = (rgb.clone());
paletteSet = true;
}
/**
* Returns the current RGB palette.
*
*
If the palette has not previously been set, or has been
* unset, an IllegalStateException will be thrown.
*
* @throws IllegalStateException if the palette is not set.
*
* @return An array of ints.
*/
public int[] getPalette()
{
if (!paletteSet)
{
throw new IllegalStateException("PNGEncodeParam3");
}
return (palette.clone());
}
/**
* Suppresses the 'PLTE' chunk from being output.
*/
public void unsetPalette()
{
palette = null;
paletteSet = false;
}
/**
* Returns true if a 'PLTE' chunk will be output.
*/
public boolean isPaletteSet()
{
return paletteSet;
}
// bKGD chunk
private int backgroundPaletteIndex;
/**
* Sets the palette index of the suggested background color.
*
*
The 'bKGD' chunk will encode this information.
*/
public void setBackgroundPaletteIndex(int index)
{
backgroundPaletteIndex = index;
backgroundSet = true;
}
/**
* Returns the palette index of the suggested background color.
*
*
If the background palette index has not previously been
* set, or has been unset, an
* IllegalStateException will be thrown.
*
* @throws IllegalStateException if the palette index is not set.
*/
public int getBackgroundPaletteIndex()
{
if (!backgroundSet)
{
throw new IllegalStateException("PNGEncodeParam4");
}
return backgroundPaletteIndex;
}
// tRNS chunk
private int[] transparency;
/**
* Sets the alpha values associated with each palette entry.
* The alpha parameter should have as many entries
* as there are RGB triples in the palette.
*
*
The 'tRNS' chunk will encode this information.
*/
public void setPaletteTransparency(byte[] alpha)
{
transparency = new int[alpha.length];
for (int i = 0; i < alpha.length; i++)
{
transparency[i] = alpha[i] & 0xff;
}
transparencySet = true;
}
/**
* Returns the alpha values associated with each palette entry.
*
*
If the palette transparency has not previously been
* set, or has been unset, an
* IllegalStateException will be thrown.
*
* @throws IllegalStateException if the palette transparency is
* not set.
*/
public byte[] getPaletteTransparency()
{
if (!transparencySet)
{
throw new IllegalStateException("PNGEncodeParam5");
}
byte[] alpha = new byte[transparency.length];
for (int i = 0; i < alpha.length; i++)
{
alpha[i] = (byte) transparency[i];
}
return alpha;
}
}
public static class Gray extends mxPngEncodeParam
{
/** Constructs an instance of PNGEncodeParam.Gray. */
public Gray()
{
}
// bKGD chunk
private boolean backgroundSet = false;
/**
* Suppresses the 'bKGD' chunk from being output.
*/
public void unsetBackground()
{
backgroundSet = false;
}
/**
* Returns true if a 'bKGD' chunk will be output.
*/
public boolean isBackgroundSet()
{
return backgroundSet;
}
/**
* Sets the desired bit depth for a grayscale image. The bit
* depth must be one of 1, 2, 4, 8, or 16.
*
*
When encoding a source image of a greater bit depth,
* pixel values will be clamped to the smaller range after
* shifting by the value given by getBitShift().
* When encoding a source image of a smaller bit depth, pixel
* values will be shifted and left-filled with zeroes.
*/
public void setBitDepth(int bitDepth)
{
if (bitDepth != 1 && bitDepth != 2 && bitDepth != 4
&& bitDepth != 8 && bitDepth != 16)
{
throw new IllegalArgumentException();
}
this.bitDepth = bitDepth;
bitDepthSet = true;
}
// bKGD chunk
private int backgroundPaletteGray;
/**
* Sets the suggested gray level of the background.
*
*
The 'bKGD' chunk will encode this information.
*/
public void setBackgroundGray(int gray)
{
backgroundPaletteGray = gray;
backgroundSet = true;
}
/**
* Returns the suggested gray level of the background.
*
*
If the background gray level has not previously been
* set, or has been unset, an
* IllegalStateException will be thrown.
*
* @throws IllegalStateException if the background gray level
* is not set.
*/
public int getBackgroundGray()
{
if (!backgroundSet)
{
throw new IllegalStateException("PNGEncodeParam6");
}
return backgroundPaletteGray;
}
// tRNS chunk
private int[] transparency;
/**
* Sets the gray value to be used to denote transparency.
*
*
Setting this attribute will cause the alpha channel
* of the input image to be ignored.
*
*
The 'tRNS' chunk will encode this information.
*/
public void setTransparentGray(int transparentGray)
{
transparency = new int[1];
transparency[0] = transparentGray;
transparencySet = true;
}
/**
* Returns the gray value to be used to denote transparency.
*
*
If the transparent gray value has not previously been
* set, or has been unset, an
* IllegalStateException will be thrown.
*
* @throws IllegalStateException if the transparent gray value
* is not set.
*/
public int getTransparentGray()
{
if (!transparencySet)
{
throw new IllegalStateException("PNGEncodeParam7");
}
int gray = transparency[0];
return gray;
}
private int bitShift;
private boolean bitShiftSet = false;
/**
* Sets the desired bit shift for a grayscale image.
* Pixels in the source image will be shifted right by
* the given amount prior to being clamped to the maximum
* value given by the encoded image's bit depth.
*/
public void setBitShift(int bitShift)
{
if (bitShift < 0)
{
throw new RuntimeException();
}
this.bitShift = bitShift;
bitShiftSet = true;
}
/**
* Returns the desired bit shift for a grayscale image.
*
*
If the bit shift has not previously been set, or has been
* unset, an IllegalStateException will be thrown.
*
* @throws IllegalStateException if the bit shift is not set.
*/
public int getBitShift()
{
if (!bitShiftSet)
{
throw new IllegalStateException("PNGEncodeParam8");
}
return bitShift;
}
/**
* Suppresses the setting of the bit shift of a grayscale image.
* Pixels in the source image will not be shifted prior to encoding.
*/
public void unsetBitShift()
{
bitShiftSet = false;
}
/**
* Returns true if the bit shift has been set.
*/
public boolean isBitShiftSet()
{
return bitShiftSet;
}
/**
* Returns true if the bit depth has been set.
*/
public boolean isBitDepthSet()
{
return bitDepthSet;
}
}
public static class RGB extends mxPngEncodeParam
{
/** Constructs an instance of PNGEncodeParam.RGB. */
public RGB()
{
}
// bKGD chunk
private boolean backgroundSet = false;
/**
* Suppresses the 'bKGD' chunk from being output.
*/
public void unsetBackground()
{
backgroundSet = false;
}
/**
* Returns true if a 'bKGD' chunk will be output.
*/
public boolean isBackgroundSet()
{
return backgroundSet;
}
/**
* Sets the desired bit depth for an RGB image. The bit
* depth must be 8 or 16.
*/
public void setBitDepth(int bitDepth)
{
if (bitDepth != 8 && bitDepth != 16)
{
throw new RuntimeException();
}
this.bitDepth = bitDepth;
bitDepthSet = true;
}
// bKGD chunk
private int[] backgroundRGB;
/**
* Sets the RGB value of the suggested background color.
* The rgb parameter should have 3 entries.
*
*
The 'bKGD' chunk will encode this information.
*/
public void setBackgroundRGB(int[] rgb)
{
if (rgb.length != 3)
{
throw new RuntimeException();
}
backgroundRGB = rgb;
backgroundSet = true;
}
/**
* Returns the RGB value of the suggested background color.
*
*
If the background color has not previously been set, or has been
* unset, an IllegalStateException will be thrown.
*
* @throws IllegalStateException if the background color is not set.
*/
public int[] getBackgroundRGB()
{
if (!backgroundSet)
{
throw new IllegalStateException("PNGEncodeParam9");
}
return backgroundRGB;
}
// tRNS chunk
private int[] transparency;
/**
* Sets the RGB value to be used to denote transparency.
*
*
Setting this attribute will cause the alpha channel
* of the input image to be ignored.
*
*
The 'tRNS' chunk will encode this information.
*/
public void setTransparentRGB(int[] transparentRGB)
{
transparency = (transparentRGB.clone());
transparencySet = true;
}
/**
* Returns the RGB value to be used to denote transparency.
*
*
If the transparent color has not previously been set,
* or has been unset, an IllegalStateException
* will be thrown.
*
* @throws IllegalStateException if the transparent color is not set.
*/
public int[] getTransparentRGB()
{
if (!transparencySet)
{
throw new IllegalStateException("PNGEncodeParam10");
}
return (transparency.clone());
}
}
protected int bitDepth;
protected boolean bitDepthSet = false;
/**
* Sets the desired bit depth of an image.
*/
public abstract void setBitDepth(int bitDepth);
/**
* 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.
*/
public int getBitDepth()
{
if (!bitDepthSet)
{
throw new IllegalStateException("PNGEncodeParam11");
}
return bitDepth;
}
/**
* 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.
*/
public void unsetBitDepth()
{
bitDepthSet = false;
}
private boolean useInterlacing = false;
/**
* Turns Adam7 interlacing on or off.
*/
public void setInterlacing(boolean useInterlacing)
{
this.useInterlacing = useInterlacing;
}
/**
* Returns true if Adam7 interlacing will be used.
*/
public boolean getInterlacing()
{
return useInterlacing;
}
// bKGD chunk - delegate to subclasses
// In JAI 1.0, 'backgroundSet' was private. The JDK 1.2 compiler
// was lenient and incorrectly allowed this variable to be
// accessed from the subclasses. The JDK 1.3 compiler correctly
// flags this as a use of a non-static variable in a static
// context. Changing 'backgroundSet' to protected would have
// solved the problem, but would have introduced a visible API
// change. Thus we are forced to adopt the solution of placing a
// separate private variable in each subclass and providing
// separate implementations of 'unsetBackground' and
// 'isBackgroundSet' in each concrete subclass.
/**
* 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.
*/
public void unsetBackground()
{
throw new RuntimeException("PNGEncodeParam23");
}
/**
* 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.
*/
public boolean isBackgroundSet()
{
throw new RuntimeException("PNGEncodeParam24");
}
// cHRM chunk
private float[] chromaticity = null;
private boolean chromaticitySet = false;
/**
* 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.
*/
public void setChromaticity(float[] chromaticity)
{
if (chromaticity.length != 8)
{
throw new IllegalArgumentException();
}
this.chromaticity = (chromaticity.clone());
chromaticitySet = true;
}
/**
* A convenience method that calls the array version.
*/
public void setChromaticity(float whitePointX, float whitePointY,
float redX, float redY, float greenX, float greenY, float blueX,
float blueY)
{
float[] chroma = new float[8];
chroma[0] = whitePointX;
chroma[1] = whitePointY;
chroma[2] = redX;
chroma[3] = redY;
chroma[4] = greenX;
chroma[5] = greenY;
chroma[6] = blueX;
chroma[7] = blueY;
setChromaticity(chroma);
}
/**
* 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.
*/
public float[] getChromaticity()
{
if (!chromaticitySet)
{
throw new IllegalStateException("PNGEncodeParam12");
}
return (chromaticity.clone());
}
/**
* Suppresses the 'cHRM' chunk from being output.
*/
public void unsetChromaticity()
{
chromaticity = null;
chromaticitySet = false;
}
/**
* Returns true if a 'cHRM' chunk will be output.
*/
public boolean isChromaticitySet()
{
return chromaticitySet;
}
// gAMA chunk
private float gamma;
private boolean gammaSet = false;
/**
* Sets the file gamma value for the image.
*
*
The 'gAMA' chunk will encode this information.
*/
public void setGamma(float gamma)
{
this.gamma = gamma;
gammaSet = true;
}
/**
* 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.
*/
public float getGamma()
{
if (!gammaSet)
{
throw new IllegalStateException("PNGEncodeParam13");
}
return gamma;
}
/**
* Suppresses the 'gAMA' chunk from being output.
*/
public void unsetGamma()
{
gammaSet = false;
}
/**
* Returns true if a 'gAMA' chunk will be output.
*/
public boolean isGammaSet()
{
return gammaSet;
}
// hIST chunk
private int[] paletteHistogram = null;
private boolean paletteHistogramSet = false;
/**
* 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.
*/
public void setPaletteHistogram(int[] paletteHistogram)
{
this.paletteHistogram = (paletteHistogram.clone());
paletteHistogramSet = true;
}
/**
* 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.
*/
public int[] getPaletteHistogram()
{
if (!paletteHistogramSet)
{
throw new IllegalStateException("PNGEncodeParam14");
}
return paletteHistogram;
}
/**
* Suppresses the 'hIST' chunk from being output.
*/
public void unsetPaletteHistogram()
{
paletteHistogram = null;
paletteHistogramSet = false;
}
/**
* Returns true if a 'hIST' chunk will be output.
*/
public boolean isPaletteHistogramSet()
{
return paletteHistogramSet;
}
// iCCP chunk
private byte[] ICCProfileData = null;
private boolean ICCProfileDataSet = false;
/**
* 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.
*/
public void setICCProfileData(byte[] ICCProfileData)
{
this.ICCProfileData = (ICCProfileData.clone());
ICCProfileDataSet = true;
}
/**
* 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.
*/
public byte[] getICCProfileData()
{
if (!ICCProfileDataSet)
{
throw new IllegalStateException("PNGEncodeParam15");
}
return (ICCProfileData.clone());
}
/**
* Suppresses the 'iCCP' chunk from being output.
*/
public void unsetICCProfileData()
{
ICCProfileData = null;
ICCProfileDataSet = false;
}
/**
* Returns true if a 'iCCP' chunk will be output.
*/
public boolean isICCProfileDataSet()
{
return ICCProfileDataSet;
}
// pHYS chunk
private int[] physicalDimension = null;
private boolean physicalDimensionSet = false;
/**
* 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.
*/
public void setPhysicalDimension(int[] physicalDimension)
{
this.physicalDimension = (physicalDimension.clone());
physicalDimensionSet = true;
}
/**
* A convenience method that calls the array version.
*/
public void setPhysicalDimension(int xPixelsPerUnit, int yPixelsPerUnit,
int unitSpecifier)
{
int[] pd = new int[3];
pd[0] = xPixelsPerUnit;
pd[1] = yPixelsPerUnit;
pd[2] = unitSpecifier;
setPhysicalDimension(pd);
}
/**
* 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.
*/
public int[] getPhysicalDimension()
{
if (!physicalDimensionSet)
{
throw new IllegalStateException("PNGEncodeParam16");
}
return (physicalDimension.clone());
}
/**
* Suppresses the 'pHYS' chunk from being output.
*/
public void unsetPhysicalDimension()
{
physicalDimension = null;
physicalDimensionSet = false;
}
/**
* Returns true if a 'pHYS' chunk will be output.
*/
public boolean isPhysicalDimensionSet()
{
return physicalDimensionSet;
}
// sPLT chunk
private mxPngSuggestedPaletteEntry[] suggestedPalette = null;
private boolean suggestedPaletteSet = false;
/**
* 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.
*/
public void setSuggestedPalette(mxPngSuggestedPaletteEntry[] palette)
{
suggestedPalette = (palette.clone());
suggestedPaletteSet = true;
}
/**
* 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.
*/
mxPngSuggestedPaletteEntry[] getSuggestedPalette()
{
if (!suggestedPaletteSet)
{
throw new IllegalStateException("PNGEncodeParam17");
}
return (suggestedPalette.clone());
}
/**
* Suppresses the 'sPLT' chunk from being output.
*/
public void unsetSuggestedPalette()
{
suggestedPalette = null;
suggestedPaletteSet = false;
}
/**
* Returns true if a 'sPLT' chunk will be output.
*/
public boolean isSuggestedPaletteSet()
{
return suggestedPaletteSet;
}
// sBIT chunk
private int[] significantBits = null;
private boolean significantBitsSet = false;
/**
* 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.
*/
public void setSignificantBits(int[] significantBits)
{
this.significantBits = (significantBits.clone());
significantBitsSet = true;
}
/**
* 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.
*/
public int[] getSignificantBits()
{
if (!significantBitsSet)
{
throw new IllegalStateException("PNGEncodeParam18");
}
return significantBits.clone();
}
/**
* Suppresses the 'sBIT' chunk from being output.
*/
public void unsetSignificantBits()
{
significantBits = null;
significantBitsSet = false;
}
/**
* Returns true if an 'sBIT' chunk will be output.
*/
public boolean isSignificantBitsSet()
{
return significantBitsSet;
}
// sRGB chunk
private int SRGBIntent;
private boolean SRGBIntentSet = false;
/**
* 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.
*/
public void setSRGBIntent(int SRGBIntent)
{
this.SRGBIntent = SRGBIntent;
SRGBIntentSet = true;
}
/**
* 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.
*/
public int getSRGBIntent()
{
if (!SRGBIntentSet)
{
throw new IllegalStateException("PNGEncodeParam19");
}
return SRGBIntent;
}
/**
* Suppresses the 'sRGB' chunk from being output.
*/
public void unsetSRGBIntent()
{
SRGBIntentSet = false;
}
/**
* Returns true if an 'sRGB' chunk will be output.
*/
public boolean isSRGBIntentSet()
{
return SRGBIntentSet;
}
// tEXt chunk
private String[] text = null;
private boolean textSet = false;
/**
* 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.
*/
public void setText(String[] text)
{
this.text = text;
textSet = true;
}
/**
* 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.
*/
public String[] getText()
{
if (!textSet)
{
throw new IllegalStateException("PNGEncodeParam20");
}
return text;
}
/**
* Suppresses the 'tEXt' chunk from being output.
*/
public void unsetText()
{
text = null;
textSet = false;
}
/**
* Returns true if a 'tEXt' chunk will be output.
*/
public boolean isTextSet()
{
return textSet;
}
// tIME chunk
private Date modificationTime;
private boolean modificationTimeSet = false;
/**
* 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.
*/
public void setModificationTime(Date modificationTime)
{
this.modificationTime = modificationTime;
modificationTimeSet = true;
}
/**
* 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.
*/
public Date getModificationTime()
{
if (!modificationTimeSet)
{
throw new IllegalStateException("PNGEncodeParam21");
}
return modificationTime;
}
/**
* Suppresses the 'tIME' chunk from being output.
*/
public void unsetModificationTime()
{
modificationTime = null;
modificationTimeSet = false;
}
/**
* Returns true if a 'tIME' chunk will be output.
*/
public boolean isModificationTimeSet()
{
return modificationTimeSet;
}
// tRNS chunk
boolean transparencySet = false;
/**
* Suppresses the 'tRNS' chunk from being output.
*/
public void unsetTransparency()
{
transparencySet = false;
}
/**
* Returns true if a 'tRNS' chunk will be output.
*/
public boolean isTransparencySet()
{
return transparencySet;
}
// zTXT chunk
private String[] zText = null;
private boolean zTextSet = false;
/**
* 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.
*/
public void setCompressedText(String[] text)
{
this.zText = text;
zTextSet = true;
}
/**
* 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.
*/
public String[] getCompressedText()
{
if (!zTextSet)
{
throw new IllegalStateException("PNGEncodeParam22");
}
return zText;
}
/**
* Suppresses the 'zTXt' chunk from being output.
*/
public void unsetCompressedText()
{
zText = null;
zTextSet = false;
}
/**
* Returns true if a 'zTXT' chunk will be output.
*/
public boolean isCompressedTextSet()
{
return zTextSet;
}
// Other chunk types
List chunkType = new ArrayList();
List chunkData = new ArrayList();
/**
* Adds a private chunk, in binary form, to the list of chunks to
* be stored with this image.
*
* @param type a 4-character String giving the chunk type name.
* @param data an array of bytes containing the
* chunk data.
*/
public synchronized void addPrivateChunk(String type, byte[] data)
{
chunkType.add(type);
chunkData.add(data.clone());
}
/**
* Returns the number of private chunks to be written to the
* output file.
*/
public synchronized int getNumPrivateChunks()
{
return chunkType.size();
}
/**
* 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.
*/
public synchronized String getPrivateChunkType(int index)
{
return chunkType.get(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.
*/
public synchronized byte[] getPrivateChunkData(int index)
{
return chunkData.get(index);
}
/**
* 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.
*/
public synchronized void removeUnsafeToCopyPrivateChunks()
{
List newChunkType = new ArrayList();
List newChunkData = new ArrayList();
int len = getNumPrivateChunks();
for (int i = 0; i < len; i++)
{
String type = getPrivateChunkType(i);
char lastChar = type.charAt(3);
if (lastChar >= 'a' && lastChar <= 'z')
{
newChunkType.add(type);
newChunkData.add(getPrivateChunkData(i));
}
}
chunkType = newChunkType;
chunkData = newChunkData;
}
/**
* Remove all private chunks associated with this parameter instance.
*/
public synchronized void removeAllPrivateChunks()
{
chunkType = new ArrayList();
chunkData = new ArrayList();
}
/**
* An abs() function for use by the Paeth predictor.
*/
private static final int abs(int x)
{
return (x < 0) ? -x : x;
}
/**
* The Paeth predictor routine used in PNG encoding. This routine
* is included as a convenience to subclasses that override the
* filterRow method.
*/
public static final int paethPredictor(int a, int b, int c)
{
int p = a + b - c;
int pa = abs(p - a);
int pb = abs(p - b);
int pc = abs(p - c);
if ((pa <= pb) && (pa <= pc))
{
return a;
}
else if (pb <= pc)
{
return b;
}
else
{
return c;
}
}
/**
* 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;
*
*
* @param 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.
* @param prevRow The current row as an array of bytes
* The pixel data starts at index bytesPerPixel;
* the initial bytesPerPixel bytes are zero.
* @param 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.
* @param bytesPerRow The number of bytes in the image row.
* This value will always be greater than 0.
* @param bytesPerPixel The number of bytes representing a single
* pixel, rounded up to an integer. This is the 'bpp' parameter
* described in the PNG specification.
*
* @return The filter type to be used. The entry of
* scratchRows[] at this index holds the
* filtered data. */
public int filterRow(byte[] currRow, byte[] prevRow, byte[][] scratchRows,
int bytesPerRow, int bytesPerPixel)
{
int[] badness = { 0, 0, 0, 0, 0 };
int curr, left, up, upleft, diff;
int pa, pb, pc;
for (int i = bytesPerPixel; i < bytesPerRow + bytesPerPixel; i++)
{
curr = currRow[i] & 0xff;
left = currRow[i - bytesPerPixel] & 0xff;
up = prevRow[i] & 0xff;
upleft = prevRow[i - bytesPerPixel] & 0xff;
// no filter
badness[0] += curr;
// sub filter
diff = curr - left;
scratchRows[1][i] = (byte) diff;
badness[1] += (diff > 0) ? diff : -diff;
// up filter
diff = curr - up;
scratchRows[2][i] = (byte) diff;
badness[2] += (diff >= 0) ? diff : -diff;
// average filter
diff = curr - ((left + up) >> 1);
scratchRows[3][i] = (byte) diff;
badness[3] += (diff >= 0) ? diff : -diff;
// paeth filter
// Original code much simplier but doesn't take full
// advantage of relationship between pa/b/c and
// information gleaned in abs operations.
/// pa = up -upleft;
/// pb = left-upleft;
/// pc = pa+pb;
/// pa = abs(pa);
/// pb = abs(pb);
/// pc = abs(pc);
/// if ((pa <= pb) && (pa <= pc))
/// diff = curr-left;
/// else if (pb <= pc)
/// diff = curr-up;
/// else
/// diff = curr-upleft;
pa = up - upleft;
pb = left - upleft;
if (pa < 0)
{
if (pb < 0)
{
// both pa & pb neg so pc is always greater than or
// equal to pa or pb;
if (pa >= pb) // since pa & pb neg check sense is reversed.
diff = curr - left;
else
diff = curr - up;
}
else
{
// pa neg pb pos so we must compute pc...
pc = pa + pb;
pa = -pa;
if (pa <= pb) // pc is positive and less than pb
if (pa <= pc)
diff = curr - left;
else
diff = curr - upleft;
else
// pc is negative and less than or equal to pa,
// but since pa is greater than pb this isn't an issue...
if (pb <= -pc)
diff = curr - up;
else
diff = curr - upleft;
}
}
else
{
if (pb < 0)
{
pb = -pb; // make it positive...
if (pa <= pb)
{
// pc would be negative and less than or equal to pb
pc = pb - pa;
if (pa <= pc)
diff = curr - left;
else if (pb == pc)
// if pa is zero then pc==pb otherwise
// pc must be less than pb.
diff = curr - up;
else
diff = curr - upleft;
}
else
{
// pc would be positive and less than pa.
pc = pa - pb;
if (pb <= pc)
diff = curr - up;
else
diff = curr - upleft;
}
}
else
{
// both pos so pa+pb is always greater than pa/pb
if (pa <= pb)
diff = curr - left;
else
diff = curr - up;
}
}
scratchRows[4][i] = (byte) diff;
badness[4] += (diff >= 0) ? diff : -diff;
}
int filterType = 0;
int minBadness = badness[0];
for (int i = 1; i < 5; i++)
{
if (badness[i] < minBadness)
{
minBadness = badness[i];
filterType = i;
}
}
if (filterType == 0)
{
System.arraycopy(currRow, bytesPerPixel, scratchRows[0],
bytesPerPixel, bytesPerRow);
}
return filterType;
}
}