Image format info
/* #IFNDEF ALT_LICENSE ThinWire(R) RIA Ajax Framework Copyright (C) 2003-2007 Custom Credit Systems This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA Users who would rather have a commercial license, warranty or support should contact the following company who invented, built and supports the technology: Custom Credit Systems, Richardson, TX 75081, USA. email: info@thinwire.com ph: +1 (888) 644-6405 http://www.thinwire.com #ENDIF [ v1.2_RC2 ] */ import java.io.DataInput; import java.io.FileInputStream; import java.io.IOException; import java.io.InputStream; import java.util.ArrayList; import java.util.List; /** * @author Joshua J. Gertzen */ public class ImageInfo { public enum Format {GIF,JPEG,PNG} private String stringValue; private String name; private Format format; private int width; private int height; public ImageInfo(String name) { setName(name); } public int getWidth() { return width; } public int getHeight() { return height; } public Format getFormat() { return format; } public String getName() { return name; } private void setName(String name) { try { InputStream is = new FileInputStream(name); if (is != null) { this.name = name; ImageParser ii = new ImageParser(); ii.setInput(is); if (!ii.check()) throw new UnsupportedOperationException("Unknown image file format for file."); switch (ii.getFormat()) { case ImageParser.FORMAT_GIF: this.format = Format.GIF; break; case ImageParser.FORMAT_JPEG: this.format = Format.JPEG; break; case ImageParser.FORMAT_PNG: this.format = Format.PNG; break; default: throw new UnsupportedOperationException("Unsupported image file format '" + ii.getFormatName() + "'."); } this.width = ii.getWidth(); this.height = ii.getHeight(); } else { this.width = -1; this.height = -1; this.format = null; this.name = ""; } } catch (Exception e) { if (!(e instanceof RuntimeException)) e = new RuntimeException(e); throw (RuntimeException)e; } } public boolean equals(Object o) { return o instanceof ImageInfo && toString().equals(o.toString()); } public int hashCode() { return toString().hashCode(); } public String toString() { if (stringValue == null) stringValue = "ImageInfo{name:" + name + ",format:" + format + ",width:" + width + ",height:" + height + "}"; return stringValue; } } /* XXX Note: This class is a public domain class that is used by * ImageInfo (above) to determine the width and height of an image. * It is made package-private because it is not intended to be used * directly. */ /* * ImageInfo.java * * Version 1.5 * * A Java class to determine image width, height and color depth for * a number of image file formats. * * Written by Marco Schmidt * <http://www.geocities.com/marcoschmidt.geo/contact.html>. * * Contributed to the Public Domain. * * Last modification 2004-02-29 */ /** * Get file format, image resolution, number of bits per pixel and optionally * number of images, comments and physical resolution from * JPEG, GIF, BMP, PCX, PNG, IFF, RAS, PBM, PGM, PPM, PSD and SWF files * (or input streams). * <p> * Use the class like this: * <pre> * ImageInfo ii = new ImageInfo(); * ii.setInput(in); // in can be InputStream or RandomAccessFile * ii.setDetermineImageNumber(true); // default is false * ii.setCollectComments(true); // default is false * if (!ii.check()) { * System.err.println("Not a supported image file format."); * return; * } * System.out.println(ii.getFormatName() + ", " + ii.getMimeType() + * ", " + ii.getWidth() + " x " + ii.getHeight() + " pixels, " + * ii.getBitsPerPixel() + " bits per pixel, " + ii.getNumberOfImages() + * " image(s), " + ii.getNumberOfComments() + " comment(s)."); * // there are other properties, check out the API documentation * </pre> * You can also use this class as a command line program. * Call it with a number of image file names and URLs as parameters: * <pre> * java ImageInfo *.jpg *.png *.gif http://somesite.tld/image.jpg * </pre> * or call it without parameters and pipe data to it: * <pre> * java ImageInfo < image.jpg * </pre> * <p> * Known limitations: * <ul> * <li>When the determination of the number of images is turned off, GIF bits * per pixel are only read from the global header. * For some GIFs, local palettes change this to a typically larger * value. To be certain to get the correct color depth, call * setDetermineImageNumber(true) before calling check(). * The complete scan over the GIF file will take additional time.</li> * <li>Transparency information is not included in the bits per pixel count. * Actually, it was my decision not to include those bits, so it's a feature! ;-)</li> * </ul> * <p> * Requirements: * <ul> * <li>Java 1.1 or higher</li> * </ul> * <p> * The latest version can be found at <a href="http://www.geocities.com/marcoschmidt.geo/image-info.html">http://www.geocities.com/marcoschmidt.geo/image-info.html</a>. * <p> * Written by <a href="http://www.geocities.com/marcoschmidt.geo/contact.html">Marco Schmidt</a>. * <p> * This class is contributed to the Public Domain. * Use it at your own risk. * <p> * Last modification 2004-02-29. * <p> * History: * <ul> * <li><strong>2001-08-24</strong> Initial version.</li> * <li><strong>2001-10-13</strong> Added support for the file formats BMP and PCX.</li> * <li><strong>2001-10-16</strong> Fixed bug in read(int[], int, int) that returned * <li><strong>2002-01-22</strong> Added support for file formats Amiga IFF and Sun Raster (RAS).</li> * <li><strong>2002-01-24</strong> Added support for file formats Portable Bitmap / Graymap / Pixmap (PBM, PGM, PPM) and Adobe Photoshop (PSD). * Added new method getMimeType() to return the MIME type associated with a particular file format.</li> * <li><strong>2002-03-15</strong> Added support to recognize number of images in file. Only works with GIF. * Use {@link #setDetermineImageNumber} with <code>true</code> as argument to identify animated GIFs * ({@link #getNumberOfImages()} will return a value larger than <code>1</code>).</li> * <li><strong>2002-04-10</strong> Fixed a bug in the feature 'determine number of images in animated GIF' introduced with version 1.1. * Thanks to Marcelo P. Lima for sending in the bug report. * Released as 1.1.1.</li> * <li><strong>2002-04-18</strong> Added {@link #setCollectComments(boolean)}. * That new method lets the user specify whether textual comments are to be * stored in an internal list when encountered in an input image file / stream. * Added two methods to return the physical width and height of the image in dpi: * {@link #getPhysicalWidthDpi()} and {@link #getPhysicalHeightDpi()}. * If the physical resolution could not be retrieved, these methods return <code>-1</code>. * </li> * <li><strong>2002-04-23</strong> Added support for the new properties physical resolution and * comments for some formats. Released as 1.2.</li> * <li><strong>2002-06-17</strong> Added support for SWF, sent in by Michael Aird. * Changed checkJpeg() so that other APP markers than APP0 will not lead to a failure anymore. * Released as 1.3.</li> * <li><strong>2003-07-28</strong> Bug fix - skip method now takes return values into consideration. * Less bytes than necessary may have been skipped, leading to flaws in the retrieved information in some cases. * Thanks to Bernard Bernstein for pointing that out. * Released as 1.4.</li> * <li><strong>2004-02-29</strong> Added support for recognizing progressive JPEG and * interlaced PNG and GIF. A new method {@link #isProgressive()} returns whether ImageInfo * has found that the storage type is progressive (or interlaced). * Thanks to Joe Germuska for suggesting the feature. * Bug fix: BMP physical resolution is now correctly determined. * Released as 1.5.</li> * </ul> */ final class ImageParser { /** * Return value of {@link #getFormat()} for JPEG streams. * ImageInfo can extract physical resolution and comments * from JPEGs (only from APP0 headers). * Only one image can be stored in a file. * It is determined whether the JPEG stream is progressive * (see {@link #isProgressive()}). */ public static final int FORMAT_JPEG = 0; /** * Return value of {@link #getFormat()} for GIF streams. * ImageInfo can extract comments from GIFs and count the number * of images (GIFs with more than one image are animations). * If you know of a place where GIFs store the physical resolution * of an image, please * <a href="http://www.geocities.com/marcoschmidt.geo/contact.html">send me a mail</a>! * It is determined whether the GIF stream is interlaced (see {@link #isProgressive()}). */ public static final int FORMAT_GIF = 1; /** * Return value of {@link #getFormat()} for PNG streams. * PNG only supports one image per file. * Both physical resolution and comments can be stored with PNG, * but ImageInfo is currently not able to extract those. * It is determined whether the PNG stream is interlaced (see {@link #isProgressive()}). */ public static final int FORMAT_PNG = 2; /** * Return value of {@link #getFormat()} for BMP streams. * BMP only supports one image per file. * BMP does not allow for comments. * The physical resolution can be stored. */ public static final int FORMAT_BMP = 3; /** * Return value of {@link #getFormat()} for PCX streams. * PCX does not allow for comments or more than one image per file. * However, the physical resolution can be stored. */ public static final int FORMAT_PCX = 4; /** * Return value of {@link #getFormat()} for IFF streams. */ public static final int FORMAT_IFF = 5; /** * Return value of {@link #getFormat()} for RAS streams. * Sun Raster allows for one image per file only and is not able to * store physical resolution or comments. */ public static final int FORMAT_RAS = 6; /** Return value of {@link #getFormat()} for PBM streams. */ public static final int FORMAT_PBM = 7; /** Return value of {@link #getFormat()} for PGM streams. */ public static final int FORMAT_PGM = 8; /** Return value of {@link #getFormat()} for PPM streams. */ public static final int FORMAT_PPM = 9; /** Return value of {@link #getFormat()} for PSD streams. */ public static final int FORMAT_PSD = 10; /** Return value of {@link #getFormat()} for SWF (Shockwave) streams. */ public static final int FORMAT_SWF = 11; public static final int COLOR_TYPE_UNKNOWN = -1; public static final int COLOR_TYPE_TRUECOLOR_RGB = 0; public static final int COLOR_TYPE_PALETTED = 1; public static final int COLOR_TYPE_GRAYSCALE= 2; public static final int COLOR_TYPE_BLACK_AND_WHITE = 3; /** * The names of all supported file formats. * The FORMAT_xyz int constants can be used as index values for * this array. */ private static final String[] FORMAT_NAMES = {"JPEG", "GIF", "PNG", "BMP", "PCX", "IFF", "RAS", "PBM", "PGM", "PPM", "PSD", "SWF"}; /** * The names of the MIME types for all supported file formats. * The FORMAT_xyz int constants can be used as index values for * this array. */ private static final String[] MIME_TYPE_STRINGS = {"image/jpeg", "image/gif", "image/png", "image/bmp", "image/pcx", "image/iff", "image/ras", "image/x-portable-bitmap", "image/x-portable-graymap", "image/x-portable-pixmap", "image/psd", "application/x-shockwave-flash"}; private int width; private int height; private int bitsPerPixel; private boolean progressive; private int format; private InputStream in; private DataInput din; private boolean collectComments = true; private List<String> comments; private boolean determineNumberOfImages; private int numberOfImages; private int physicalHeightDpi; private int physicalWidthDpi; private int bitBuf; private int bitPos; private void addComment(String s) { if (comments == null) { comments = new ArrayList<String>(); } comments.add(s); } /** * Call this method after you have provided an input stream or file * using {@link #setInput(InputStream)} or {@link #setInput(DataInput)}. * If true is returned, the file format was known and information * on the file's content can be retrieved using the various getXyz methods. * @return if information could be retrieved from input */ public boolean check() { format = -1; width = -1; height = -1; bitsPerPixel = -1; numberOfImages = 1; physicalHeightDpi = -1; physicalWidthDpi = -1; comments = null; try { int b1 = read() & 0xff; int b2 = read() & 0xff; if (b1 == 0x47 && b2 == 0x49) { return checkGif(); } else if (b1 == 0x89 && b2 == 0x50) { return checkPng(); } else if (b1 == 0xff && b2 == 0xd8) { return checkJpeg(); } else if (b1 == 0x42 && b2 == 0x4d) { return checkBmp(); } else if (b1 == 0x0a && b2 < 0x06) { return checkPcx(); } else if (b1 == 0x46 && b2 == 0x4f) { return checkIff(); } else if (b1 == 0x59 && b2 == 0xa6) { return checkRas(); } else if (b1 == 0x50 && b2 >= 0x31 && b2 <= 0x36) { return checkPnm(b2 - '0'); } else if (b1 == 0x38 && b2 == 0x42) { return checkPsd(); } else if (b1 == 0x46 && b2 == 0x57) { return checkSwf(); } else { return false; } } catch (IOException ioe) { return false; } } private boolean checkBmp() throws IOException { byte[] a = new byte[44]; if (read(a) != a.length) { return false; } width = getIntLittleEndian(a, 16); height = getIntLittleEndian(a, 20); if (width < 1 || height < 1) { return false; } bitsPerPixel = getShortLittleEndian(a, 26); if (bitsPerPixel != 1 && bitsPerPixel != 4 && bitsPerPixel != 8 && bitsPerPixel != 16 && bitsPerPixel != 24 && bitsPerPixel != 32) { return false; } int x = (int)(getIntLittleEndian(a, 36) * 0.0254); if (x > 0) { setPhysicalWidthDpi(x); } int y = (int)(getIntLittleEndian(a, 40) * 0.0254); if (y > 0) { setPhysicalHeightDpi(y); } format = FORMAT_BMP; return true; } private boolean checkGif() throws IOException { final byte[] GIF_MAGIC_87A = {0x46, 0x38, 0x37, 0x61}; final byte[] GIF_MAGIC_89A = {0x46, 0x38, 0x39, 0x61}; byte[] a = new byte[11]; // 4 from the GIF signature + 7 from the global header if (read(a) != 11) { return false; } if ((!equals(a, 0, GIF_MAGIC_89A, 0, 4)) && (!equals(a, 0, GIF_MAGIC_87A, 0, 4))) { return false; } format = FORMAT_GIF; width = getShortLittleEndian(a, 4); height = getShortLittleEndian(a, 6); int flags = a[8] & 0xff; bitsPerPixel = ((flags >> 4) & 0x07) + 1; progressive = (flags & 0x02) != 0; if (!determineNumberOfImages) { return true; } // skip global color palette if ((flags & 0x80) != 0) { int tableSize = (1 << ((flags & 7) + 1)) * 3; skip(tableSize); } numberOfImages = 0; int blockType; do { blockType = read(); switch(blockType) { case(0x2c): // image separator { if (read(a, 0, 9) != 9) { return false; } flags = a[8] & 0xff; int localBitsPerPixel = (flags & 0x07) + 1; if (localBitsPerPixel > bitsPerPixel) { bitsPerPixel = localBitsPerPixel; } if ((flags & 0x80) != 0) { skip((1 << localBitsPerPixel) * 3); } skip(1); // initial code length int n; do { n = read(); if (n > 0) { skip(n); } else if (n == -1) { return false; } } while (n > 0); numberOfImages++; break; } case(0x21): // extension { int extensionType = read(); if (collectComments && extensionType == 0xfe) { StringBuilder sb = new StringBuilder(); int n; do { n = read(); if (n == -1) { return false; } if (n > 0) { for (int i = 0; i < n; i++) { int ch = read(); if (ch == -1) { return false; } sb.append((char)ch); } } } while (n > 0); } else { int n; do { n = read(); if (n > 0) { skip(n); } else if (n == -1) { return false; } } while (n > 0); } break; } case(0x3b): // end of file { break; } default: { return false; } } } while (blockType != 0x3b); return true; } private boolean checkIff() throws IOException { byte[] a = new byte[10]; // read remaining 2 bytes of file id, 4 bytes file size // and 4 bytes IFF subformat if (read(a, 0, 10) != 10) { return false; } final byte[] IFF_RM = {0x52, 0x4d}; if (!equals(a, 0, IFF_RM, 0, 2)) { return false; } int type = getIntBigEndian(a, 6); if (type != 0x494c424d && // type must be ILBM... type != 0x50424d20) { // ...or PBM return false; } // loop chunks to find BMHD chunk do { if (read(a, 0, 8) != 8) { return false; } int chunkId = getIntBigEndian(a, 0); int size = getIntBigEndian(a, 4); if ((size & 1) == 1) { size++; } if (chunkId == 0x424d4844) { // BMHD chunk if (read(a, 0, 9) != 9) { return false; } format = FORMAT_IFF; width = getShortBigEndian(a, 0); height = getShortBigEndian(a, 2); bitsPerPixel = a[8] & 0xff; return (width > 0 && height > 0 && bitsPerPixel > 0 && bitsPerPixel < 33); } else { skip(size); } } while (true); } private boolean checkJpeg() throws IOException { byte[] data = new byte[12]; while (true) { if (read(data, 0, 4) != 4) { return false; } int marker = getShortBigEndian(data, 0); int size = getShortBigEndian(data, 2); if ((marker & 0xff00) != 0xff00) { return false; // not a valid marker } if (marker == 0xffe0) { // APPx if (size < 14) { return false; // APPx header must be >= 14 bytes } if (read(data, 0, 12) != 12) { return false; } final byte[] APP0_ID = {0x4a, 0x46, 0x49, 0x46, 0x00}; if (equals(APP0_ID, 0, data, 0, 5)) { if (data[7] == 1) { setPhysicalWidthDpi(getShortBigEndian(data, 8)); setPhysicalHeightDpi(getShortBigEndian(data, 10)); } else if (data[7] == 2) { int x = getShortBigEndian(data, 8); int y = getShortBigEndian(data, 10); setPhysicalWidthDpi((int)(x * 2.54f)); setPhysicalHeightDpi((int)(y * 2.54f)); } } skip(size - 14); } else if (collectComments && size > 2 && marker == 0xfffe) { // comment size -= 2; byte[] chars = new byte[size]; if (read(chars, 0, size) != size) { return false; } String comment = new String(chars, "iso-8859-1"); comment = comment.trim(); addComment(comment); } else if (marker >= 0xffc0 && marker <= 0xffcf && marker != 0xffc4 && marker != 0xffc8) { if (read(data, 0, 6) != 6) { return false; } format = FORMAT_JPEG; bitsPerPixel = (data[0] & 0xff) * (data[5] & 0xff); progressive = marker == 0xffc2 || marker == 0xffc6 || marker == 0xffca || marker == 0xffce; width = getShortBigEndian(data, 3); height = getShortBigEndian(data, 1); return true; } else { skip(size - 2); } } } private boolean checkPcx() throws IOException { byte[] a = new byte[64]; if (read(a) != a.length) { return false; } if (a[0] != 1) { // encoding, 1=RLE is only valid value return false; } // width / height int x1 = getShortLittleEndian(a, 2); int y1 = getShortLittleEndian(a, 4); int x2 = getShortLittleEndian(a, 6); int y2 = getShortLittleEndian(a, 8); if (x1 < 0 || x2 < x1 || y1 < 0 || y2 < y1) { return false; } width = x2 - x1 + 1; height = y2 - y1 + 1; // color depth int bits = a[1]; int planes = a[63]; if (planes == 1 && (bits == 1 || bits == 2 || bits == 4 || bits == 8)) { // paletted bitsPerPixel = bits; } else if (planes == 3 && bits == 8) { // RGB truecolor bitsPerPixel = 24; } else { return false; } setPhysicalWidthDpi(getShortLittleEndian(a, 10)); setPhysicalHeightDpi(getShortLittleEndian(a, 10)); format = FORMAT_PCX; return true; } private boolean checkPng() throws IOException { final byte[] PNG_MAGIC = {0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a}; byte[] a = new byte[27]; if (read(a) != 27) { return false; } if (!equals(a, 0, PNG_MAGIC, 0, 6)) { return false; } format = FORMAT_PNG; width = getIntBigEndian(a, 14); height = getIntBigEndian(a, 18); bitsPerPixel = a[22] & 0xff; int colorType = a[23] & 0xff; if (colorType == 2 || colorType == 6) { bitsPerPixel *= 3; } progressive = (a[26] & 0xff) != 0; return true; } private boolean checkPnm(int id) throws IOException { if (id < 1 || id > 6) { return false; } final int[] PNM_FORMATS = {FORMAT_PBM, FORMAT_PGM, FORMAT_PPM}; format = PNM_FORMATS[(id - 1) % 3]; boolean hasPixelResolution = false; String s; while (true) { s = readLine(); if (s != null) { s = s.trim(); } if (s == null || s.length() < 1) { continue; } if (s.charAt(0) == '#') { // comment if (collectComments && s.length() > 1) { addComment(s.substring(1)); } continue; } if (!hasPixelResolution) { // split "343 966" into width=343, height=966 int spaceIndex = s.indexOf(' '); if (spaceIndex == -1) { return false; } String widthString = s.substring(0, spaceIndex); spaceIndex = s.lastIndexOf(' '); if (spaceIndex == -1) { return false; } String heightString = s.substring(spaceIndex + 1); try { width = Integer.parseInt(widthString); height = Integer.parseInt(heightString); } catch (NumberFormatException nfe) { return false; } if (width < 1 || height < 1) { return false; } if (format == FORMAT_PBM) { bitsPerPixel = 1; return true; } hasPixelResolution = true; } else { int maxSample; try { maxSample = Integer.parseInt(s); } catch (NumberFormatException nfe) { return false; } if (maxSample < 0) { return false; } for (int i = 0; i < 25; i++) { if (maxSample < (1 << (i + 1))) { bitsPerPixel = i + 1; if (format == FORMAT_PPM) { bitsPerPixel *= 3; } return true; } } return false; } } } private boolean checkPsd() throws IOException { byte[] a = new byte[24]; if (read(a) != a.length) { return false; } final byte[] PSD_MAGIC = {0x50, 0x53}; if (!equals(a, 0, PSD_MAGIC, 0, 2)) { return false; } format = FORMAT_PSD; width = getIntBigEndian(a, 16); height = getIntBigEndian(a, 12); int channels = getShortBigEndian(a, 10); int depth = getShortBigEndian(a, 20); bitsPerPixel = channels * depth; return (width > 0 && height > 0 && bitsPerPixel > 0 && bitsPerPixel <= 64); } private boolean checkRas() throws IOException { byte[] a = new byte[14]; if (read(a) != a.length) { return false; } final byte[] RAS_MAGIC = {0x6a, (byte)0x95}; if (!equals(a, 0, RAS_MAGIC, 0, 2)) { return false; } format = FORMAT_RAS; width = getIntBigEndian(a, 2); height = getIntBigEndian(a, 6); bitsPerPixel = getIntBigEndian(a, 10); return (width > 0 && height > 0 && bitsPerPixel > 0 && bitsPerPixel <= 24); } // Written by Michael Aird. private boolean checkSwf() throws IOException { //get rid of the last byte of the signature, the byte of the version and 4 bytes of the size byte[] a = new byte[6]; if (read(a) != a.length) { return false; } format = FORMAT_SWF; int bitSize = (int)readUBits( 5 ); int maxX = (int)readSBits( bitSize ); int maxY = (int)readSBits( bitSize ); width = maxX/20; //cause we're in twips height = maxY/20; //cause we're in twips setPhysicalWidthDpi(72); setPhysicalHeightDpi(72); return (width > 0 && height > 0); } private boolean equals(byte[] a1, int offs1, byte[] a2, int offs2, int num) { while (num-- > 0) { if (a1[offs1++] != a2[offs2++]) { return false; } } return true; } /** * If {@link #check()} was successful, returns the image's number of bits per pixel. * Does not include transparency information like the alpha channel. * @return number of bits per image pixel */ public int getBitsPerPixel() { return bitsPerPixel; } /** * Returns the index'th comment retrieved from the image. * @throws IllegalArgumentException if index is smaller than 0 or larger than or equal * to the number of comments retrieved * @see #getNumberOfComments */ public String getComment(int index) { if (comments == null || index < 0 || index >= comments.size()) { throw new IllegalArgumentException("Not a valid comment index: " + index); } return comments.get(index); } /** * If {@link #check()} was successful, returns the image format as one * of the FORMAT_xyz constants from this class. * Use {@link #getFormatName()} to get a textual description of the file format. * @return file format as a FORMAT_xyz constant */ public int getFormat() { return format; } /** * If {@link #check()} was successful, returns the image format's name. * Use {@link #getFormat()} to get a unique number. * @return file format name */ public String getFormatName() { if (format >= 0 && format < FORMAT_NAMES.length) { return FORMAT_NAMES[format]; } else { return "?"; } } /** * If {@link #check()} was successful, returns one the image's vertical * resolution in pixels. * @return image height in pixels */ public int getHeight() { return height; } private int getIntBigEndian(byte[] a, int offs) { return (a[offs] & 0xff) << 24 | (a[offs + 1] & 0xff) << 16 | (a[offs + 2] & 0xff) << 8 | a[offs + 3] & 0xff; } private int getIntLittleEndian(byte[] a, int offs) { return (a[offs + 3] & 0xff) << 24 | (a[offs + 2] & 0xff) << 16 | (a[offs + 1] & 0xff) << 8 | a[offs] & 0xff; } /** * If {@link #check()} was successful, returns a String with the * MIME type of the format. * @return MIME type, e.g. <code>image/jpeg</code> */ public String getMimeType() { if (format >= 0 && format < MIME_TYPE_STRINGS.length) { if (format == FORMAT_JPEG && progressive) { return "image/pjpeg"; } return MIME_TYPE_STRINGS[format]; } else { return null; } } /** * If {@link #check()} was successful and {@link #setCollectComments(boolean)} was called with * <code>true</code> as argument, returns the number of comments retrieved * from the input image stream / file. * Any number >= 0 and smaller than this number of comments is then a * valid argument for the {@link #getComment(int)} method. * @return number of comments retrieved from input image */ public int getNumberOfComments() { if (comments == null) { return 0; } else { return comments.size(); } } /** * Returns the number of images in the examined file. * Assumes that <code>setDetermineImageNumber(true);</code> was called before * a successful call to {@link #check()}. * This value can currently be only different from <code>1</code> for GIF images. * @return number of images in file */ public int getNumberOfImages() { return numberOfImages; } /** * Returns the physical height of this image in dots per inch (dpi). * Assumes that {@link #check()} was successful. * Returns <code>-1</code> on failure. * @return physical height (in dpi) * @see #getPhysicalWidthDpi() * @see #getPhysicalHeightInch() */ public int getPhysicalHeightDpi() { return physicalHeightDpi; } /** * If {@link #check()} was successful, returns the physical width of this image in dpi (dots per inch) * or -1 if no value could be found. * @return physical height (in dpi) * @see #getPhysicalHeightDpi() * @see #getPhysicalWidthDpi() * @see #getPhysicalWidthInch() */ public float getPhysicalHeightInch() { int h = getHeight(); int ph = getPhysicalHeightDpi(); if (h > 0 && ph > 0) { return ((float)h) / ((float)ph); } else { return -1.0f; } } /** * If {@link #check()} was successful, returns the physical width of this image in dpi (dots per inch) * or -1 if no value could be found. * @return physical width (in dpi) * @see #getPhysicalHeightDpi() * @see #getPhysicalWidthInch() * @see #getPhysicalHeightInch() */ public int getPhysicalWidthDpi() { return physicalWidthDpi; } /** * Returns the physical width of an image in inches, or * <code>-1.0f</code> if width information is not available. * Assumes that {@link #check} has been called successfully. * @return physical width in inches or <code>-1.0f</code> on failure * @see #getPhysicalWidthDpi * @see #getPhysicalHeightInch */ public float getPhysicalWidthInch() { int w = getWidth(); int pw = getPhysicalWidthDpi(); if (w > 0 && pw > 0) { return ((float)w) / ((float)pw); } else { return -1.0f; } } private int getShortBigEndian(byte[] a, int offs) { return (a[offs] & 0xff) << 8 | (a[offs + 1] & 0xff); } private int getShortLittleEndian(byte[] a, int offs) { return (a[offs] & 0xff) | (a[offs + 1] & 0xff) << 8; } /** * If {@link #check()} was successful, returns one the image's horizontal * resolution in pixels. * @return image width in pixels */ public int getWidth() { return width; } /** * Returns whether the image is stored in a progressive (also called: interlaced) way. * @return true for progressive/interlaced, false otherwise */ public boolean isProgressive() { return progressive; } private int read() throws IOException { if (in != null) { return in.read(); } else { return din.readByte(); } } private int read(byte[] a) throws IOException { if (in != null) { return in.read(a); } else { din.readFully(a); return a.length; } } private int read(byte[] a, int offset, int num) throws IOException { if (in != null) { return in.read(a, offset, num); } else { din.readFully(a, offset, num); return num; } } private String readLine() throws IOException { return readLine(new StringBuilder()); } private String readLine(StringBuilder sb) throws IOException { boolean finished; do { int value = read(); finished = (value == -1 || value == 10); if (!finished) { sb.append((char)value); } } while (!finished); return sb.toString(); } private long readUBits( int numBits ) throws IOException { if (numBits == 0) { return 0; } int bitsLeft = numBits; long result = 0; if (bitPos == 0) { //no value in the buffer - read a byte if (in != null) { bitBuf = in.read(); } else { bitBuf = din.readByte(); } bitPos = 8; } while( true ) { int shift = bitsLeft - bitPos; if( shift > 0 ) { // Consume the entire buffer result |= bitBuf << shift; bitsLeft -= bitPos; // Get the next byte from the input stream if (in != null) { bitBuf = in.read(); } else { bitBuf = din.readByte(); } bitPos = 8; } else { // Consume a portion of the buffer result |= bitBuf >> -shift; bitPos -= bitsLeft; bitBuf &= 0xff >> (8 - bitPos); // mask off the consumed bits return result; } } } /** * Read a signed value from the given number of bits */ private int readSBits( int numBits ) throws IOException { // Get the number as an unsigned value. long uBits = readUBits( numBits ); // Is the number negative? if( ( uBits & (1L << (numBits - 1))) != 0 ) { // Yes. Extend the sign. uBits |= -1L << numBits; } return (int)uBits; } /** * Specify whether textual comments are supposed to be extracted from input. * Default is <code>false</code>. * If enabled, comments will be added to an internal list. * @param newValue if <code>true</code>, this class will read comments * @see #getNumberOfComments * @see #getComment */ public void setCollectComments(boolean newValue) { collectComments = newValue; } /** * Specify whether the number of images in a file is to be * determined - default is <code>false</code>. * This is a special option because some file formats require running over * the entire file to find out the number of images, a rather time-consuming * task. * Not all file formats support more than one image. * If this method is called with <code>true</code> as argument, * the actual number of images can be queried via * {@link #getNumberOfImages()} after a successful call to * {@link #check()}. * @param newValue will the number of images be determined? * @see #getNumberOfImages */ public void setDetermineImageNumber(boolean newValue) { determineNumberOfImages = newValue; } /** * Set the input stream to the argument stream (or file). * Note that {@link java.io.RandomAccessFile} implements * {@link java.io.DataInput}. * @param dataInput the input stream to read from */ public void setInput(DataInput dataInput) { din = dataInput; in = null; } /** * Set the input stream to the argument stream (or file). * @param inputStream the input stream to read from */ public void setInput(InputStream inputStream) { in = inputStream; din = null; } private void setPhysicalHeightDpi(int newValue) { physicalWidthDpi = newValue; } private void setPhysicalWidthDpi(int newValue) { physicalHeightDpi = newValue; } private void skip(int num) throws IOException { while (num > 0) { long result; if (in != null) { result = in.skip(num); } else { result = din.skipBytes(num); } if (result > 0) { num -= result; } } } }