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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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package com.sun.imageio.plugins.jpeg;

import javax.imageio.ImageTypeSpecifier;
import javax.imageio.plugins.jpeg.JPEGQTable;
import javax.imageio.plugins.jpeg.JPEGHuffmanTable;

import java.awt.image.ColorModel;
import java.awt.color.ColorSpace;
import java.awt.color.ICC_ColorSpace;

A class containing JPEG-related constants, definitions, and static methods. This class and its constants must be public so that JPEGImageWriteParam can see it.
/** * A class containing JPEG-related constants, definitions, and * static methods. This class and its constants must be public so that * <code>JPEGImageWriteParam</code> can see it. */
public class JPEG { // List of all the JPEG markers (pre-JPEG2000)
For temporary use in arithmetic coding
/** For temporary use in arithmetic coding */
public static final int TEM = 0x01; // Codes 0x02 - 0xBF are reserved // SOF markers for Nondifferential Huffman coding
Baseline DCT
/** Baseline DCT */
public static final int SOF0 = 0xC0;
Extended Sequential DCT
/** Extended Sequential DCT */
public static final int SOF1 = 0xC1;
Progressive DCT
/** Progressive DCT */
public static final int SOF2 = 0xC2;
Lossless Sequential
/** Lossless Sequential */
public static final int SOF3 = 0xC3;
Define Huffman Tables
/** Define Huffman Tables */
public static final int DHT = 0xC4; // SOF markers for Differential Huffman coding
Differential Sequential DCT
/** Differential Sequential DCT */
public static final int SOF5 = 0xC5;
Differential Progressive DCT
/** Differential Progressive DCT */
public static final int SOF6 = 0xC6;
Differential Lossless
/** Differential Lossless */
public static final int SOF7 = 0xC7;
Reserved for JPEG extensions
/** Reserved for JPEG extensions */
public static final int JPG = 0xC8; // SOF markers for Nondifferential arithmetic coding
Extended Sequential DCT, Arithmetic coding
/** Extended Sequential DCT, Arithmetic coding */
public static final int SOF9 = 0xC9;
Progressive DCT, Arithmetic coding
/** Progressive DCT, Arithmetic coding */
public static final int SOF10 = 0xCA;
Lossless Sequential, Arithmetic coding
/** Lossless Sequential, Arithmetic coding */
public static final int SOF11 = 0xCB;
Define Arithmetic conditioning tables
/** Define Arithmetic conditioning tables */
public static final int DAC = 0xCC; // SOF markers for Differential arithmetic coding
Differential Sequential DCT, Arithmetic coding
/** Differential Sequential DCT, Arithmetic coding */
public static final int SOF13 = 0xCD;
Differential Progressive DCT, Arithmetic coding
/** Differential Progressive DCT, Arithmetic coding */
public static final int SOF14 = 0xCE;
Differential Lossless, Arithmetic coding
/** Differential Lossless, Arithmetic coding */
public static final int SOF15 = 0xCF; // Restart Markers public static final int RST0 = 0xD0; public static final int RST1 = 0xD1; public static final int RST2 = 0xD2; public static final int RST3 = 0xD3; public static final int RST4 = 0xD4; public static final int RST5 = 0xD5; public static final int RST6 = 0xD6; public static final int RST7 = 0xD7;
Number of restart markers
/** Number of restart markers */
public static final int RESTART_RANGE = 8;
Start of Image
/** Start of Image */
public static final int SOI = 0xD8;
End of Image
/** End of Image */
public static final int EOI = 0xD9;
Start of Scan
/** Start of Scan */
public static final int SOS = 0xDA;
Define Quantisation Tables
/** Define Quantisation Tables */
public static final int DQT = 0xDB;
Define Number of lines
/** Define Number of lines */
public static final int DNL = 0xDC;
Define Restart Interval
/** Define Restart Interval */
public static final int DRI = 0xDD;
Define Heirarchical progression
/** Define Heirarchical progression */
public static final int DHP = 0xDE;
Expand reference image(s)
/** Expand reference image(s) */
public static final int EXP = 0xDF; // Application markers
APP0 used by JFIF
/** APP0 used by JFIF */
public static final int APP0 = 0xE0; public static final int APP1 = 0xE1; public static final int APP2 = 0xE2; public static final int APP3 = 0xE3; public static final int APP4 = 0xE4; public static final int APP5 = 0xE5; public static final int APP6 = 0xE6; public static final int APP7 = 0xE7; public static final int APP8 = 0xE8; public static final int APP9 = 0xE9; public static final int APP10 = 0xEA; public static final int APP11 = 0xEB; public static final int APP12 = 0xEC; public static final int APP13 = 0xED;
APP14 used by Adobe
/** APP14 used by Adobe */
public static final int APP14 = 0xEE; public static final int APP15 = 0xEF; // codes 0xF0 to 0xFD are reserved
Comment marker
/** Comment marker */
public static final int COM = 0xFE; // JFIF Resolution units
The X and Y units simply indicate the aspect ratio of the pixels.
/** The X and Y units simply indicate the aspect ratio of the pixels. */
public static final int DENSITY_UNIT_ASPECT_RATIO = 0;
Pixel density is in pixels per inch.
/** Pixel density is in pixels per inch. */
public static final int DENSITY_UNIT_DOTS_INCH = 1;
Pixel density is in pixels per centemeter.
/** Pixel density is in pixels per centemeter. */
public static final int DENSITY_UNIT_DOTS_CM = 2;
The max known value for DENSITY_UNIT
/** The max known value for DENSITY_UNIT */
public static final int NUM_DENSITY_UNIT = 3; // Adobe transform values public static final int ADOBE_IMPOSSIBLE = -1; public static final int ADOBE_UNKNOWN = 0; public static final int ADOBE_YCC = 1; public static final int ADOBE_YCCK = 2; // Spi initialization stuff public static final String vendor = "Oracle Corporation"; public static final String version = "0.5"; // Names of the formats we can read or write static final String [] names = {"JPEG", "jpeg", "JPG", "jpg"}; static final String [] suffixes = {"jpg", "jpeg"}; static final String [] MIMETypes = {"image/jpeg"}; public static final String nativeImageMetadataFormatName = "javax_imageio_jpeg_image_1.0"; public static final String nativeImageMetadataFormatClassName = "com.sun.imageio.plugins.jpeg.JPEGImageMetadataFormat"; public static final String nativeStreamMetadataFormatName = "javax_imageio_jpeg_stream_1.0"; public static final String nativeStreamMetadataFormatClassName = "com.sun.imageio.plugins.jpeg.JPEGStreamMetadataFormat"; // IJG Color codes. public static final int JCS_UNKNOWN = 0; // error/unspecified public static final int JCS_GRAYSCALE = 1; // monochrome public static final int JCS_RGB = 2; // red/green/blue public static final int JCS_YCbCr = 3; // Y/Cb/Cr (also known as YUV) public static final int JCS_CMYK = 4; // C/M/Y/K public static final int JCS_YCC = 5; // PhotoYCC public static final int JCS_RGBA = 6; // RGB-Alpha public static final int JCS_YCbCrA = 7; // Y/Cb/Cr/Alpha // 8 and 9 were old "Legacy" codes which the old code never identified // on reading anyway. Support for writing them is being dropped, too. public static final int JCS_YCCA = 10; // PhotoYCC-Alpha public static final int JCS_YCCK = 11; // Y/Cb/Cr/K public static final int NUM_JCS_CODES = JCS_YCCK+1;
IJG can handle up to 4-channel JPEGs
/** IJG can handle up to 4-channel JPEGs */
static final int [] [] bandOffsets = {{0}, {0, 1}, {0, 1, 2}, {0, 1, 2, 3}}; static final int [] bOffsRGB = { 2, 1, 0 }; /* These are kept in the inner class to avoid static initialization * of the CMM class until someone actually needs it. * (e.g. do not init CMM on the request for jpeg mime types) */ public static class JCS { public static final ColorSpace sRGB = ColorSpace.getInstance(ColorSpace.CS_sRGB); private static ColorSpace YCC = null; private static boolean yccInited = false; public static ColorSpace getYCC() { if (!yccInited) { try { YCC = ColorSpace.getInstance(ColorSpace.CS_PYCC); } catch (IllegalArgumentException e) { // PYCC.pf may not always be installed } finally { yccInited = true; } } return YCC; } } // Default value for ImageWriteParam public static final float DEFAULT_QUALITY = 0.75F;
Returns true if the given ColorSpace object is an instance of ICC_ColorSpace but is not one of the standard ColorSpaces returned by ColorSpace.getInstance().
/** * Returns <code>true</code> if the given <code>ColorSpace</code> * object is an instance of ICC_ColorSpace but is not one of the * standard <code>ColorSpaces</code> returned by * <code>ColorSpace.getInstance()</code>. */
static boolean isNonStandardICC(ColorSpace cs) { boolean retval = false; if ((cs instanceof ICC_ColorSpace) && (!cs.isCS_sRGB()) && (!cs.equals(ColorSpace.getInstance(ColorSpace.CS_CIEXYZ))) && (!cs.equals(ColorSpace.getInstance(ColorSpace.CS_GRAY))) && (!cs.equals(ColorSpace.getInstance(ColorSpace.CS_LINEAR_RGB))) && (!cs.equals(ColorSpace.getInstance(ColorSpace.CS_PYCC))) ) { retval = true; } return retval; }
Returns true if the given imageType can be used in a JFIF file. If input is true, then the image type is considered before colorspace conversion.
/** * Returns <code>true</code> if the given imageType can be used * in a JFIF file. If <code>input</code> is true, then the * image type is considered before colorspace conversion. */
static boolean isJFIFcompliant(ImageTypeSpecifier imageType, boolean input) { ColorModel cm = imageType.getColorModel(); // Can't have alpha if (cm.hasAlpha()) { return false; } // Gray is OK, always int numComponents = imageType.getNumComponents(); if (numComponents == 1) { return true; } // If it isn't gray, it must have 3 channels if (numComponents != 3) { return false; } if (input) { // Must be RGB if (cm.getColorSpace().getType() == ColorSpace.TYPE_RGB) { return true; } } else { // Must be YCbCr if (cm.getColorSpace().getType() == ColorSpace.TYPE_YCbCr) { return true; } } return false; }
Given an image type, return the Adobe transform corresponding to that type, or ADOBE_IMPOSSIBLE if the image type is incompatible with an Adobe marker segment. If input is true, then the image type is considered before colorspace conversion.
/** * Given an image type, return the Adobe transform corresponding to * that type, or ADOBE_IMPOSSIBLE if the image type is incompatible * with an Adobe marker segment. If <code>input</code> is true, then * the image type is considered before colorspace conversion. */
static int transformForType(ImageTypeSpecifier imageType, boolean input) { int retval = ADOBE_IMPOSSIBLE; ColorModel cm = imageType.getColorModel(); switch (cm.getColorSpace().getType()) { case ColorSpace.TYPE_GRAY: retval = ADOBE_UNKNOWN; break; case ColorSpace.TYPE_RGB: retval = input ? ADOBE_YCC : ADOBE_UNKNOWN; break; case ColorSpace.TYPE_YCbCr: retval = ADOBE_YCC; break; case ColorSpace.TYPE_CMYK: retval = input ? ADOBE_YCCK : ADOBE_IMPOSSIBLE; } return retval; }
Converts an ImageWriteParam (i.e. IJG) non-linear quality value to a float suitable for passing to JPEGQTable.getScaledInstance().
/** * Converts an ImageWriteParam (i.e. IJG) non-linear quality value * to a float suitable for passing to JPEGQTable.getScaledInstance(). */
static float convertToLinearQuality(float quality) { // The following is converted from the IJG code. if (quality <= 0.0F) { quality = 0.01F; } if (quality > 1.00F) { quality = 1.00F; } if (quality < 0.5F) { quality = 0.5F / quality; } else { quality = 2.0F - (quality * 2.0F); } return quality; }
Return an array of default, visually lossless quantization tables.
/** * Return an array of default, visually lossless quantization tables. */
static JPEGQTable [] getDefaultQTables() { JPEGQTable [] qTables = new JPEGQTable[2]; qTables[0] = JPEGQTable.K1Div2Luminance; qTables[1] = JPEGQTable.K2Div2Chrominance; return qTables; }
Return an array of default Huffman tables.
/** * Return an array of default Huffman tables. */
static JPEGHuffmanTable [] getDefaultHuffmanTables(boolean wantDC) { JPEGHuffmanTable [] tables = new JPEGHuffmanTable[2]; if (wantDC) { tables[0] = JPEGHuffmanTable.StdDCLuminance; tables[1] = JPEGHuffmanTable.StdDCChrominance; } else { tables[0] = JPEGHuffmanTable.StdACLuminance; tables[1] = JPEGHuffmanTable.StdACChrominance; } return tables; } }