001 /* 002 Copyright (C) 2004 Laurent Martelli <laurent@aopsys.com> 003 004 This program is free software; you can redistribute it and/or modify 005 it under the terms of the GNU Lesser General Public License as 006 published by the Free Software Foundation; either version 2 of the 007 License, or (at your option) any later version. 008 009 This program is distributed in the hope that it will be useful, 010 but WITHOUT ANY WARRANTY; without even the implied warranty of 011 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 012 GNU Lesser General Public License for more details. 013 014 You should have received a copy of the GNU Lesser General Public License 015 along with this program; if not, write to the Free Software 016 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ 017 018 package org.objectweb.jac.util; 019 020 import java.awt.Dimension; 021 import java.io.File; 022 import java.io.IOException; 023 import java.io.InputStream; 024 import java.util.Arrays; 025 import org.apache.log4j.Logger; 026 027 /** 028 * Contains various methods related to image files 029 */ 030 031 public class Images { 032 static Logger logger = Logger.getLogger("images"); 033 034 protected static final byte[] 035 PNG_SIG = new byte[] {-119, 'P', 'N', 'G', 13, 10, 26, 10}; 036 protected static final byte[] 037 GIF87A_SIG = new byte[] {'G', 'I', 'F', '8', '7', 'a' }; 038 protected static final byte[] 039 GIF89A_SIG = new byte[] {'G', 'I', 'F', '8', '9', 'a' }; 040 protected static final byte[] 041 JFIF_SIG = new byte[] {-1, -40, -1, -32, 0, 0, 'J', 'F', 'I', 'F'}; 042 043 044 /** 045 * Tells the size of an image. Supported formats are GIF and PNG. 046 * 047 * @param img the file of the image 048 * @return The size of the image, null if the image format is unhandled 049 * 050 * @see #getImageSize(InputStream) 051 */ 052 public static Dimension getImageFileSize(File img) 053 throws IOException 054 { 055 return getImageSize( 056 Images.class.getClassLoader().getResourceAsStream( 057 img.getPath())); 058 } 059 060 /** 061 * Tells the size of an image. Supported formats are GIF and PNG. 062 * 063 * @param img the data of the image 064 * @return The size of the image, null if the image format is unhandled 065 * 066 * @see #getImageFileSize(File) 067 */ 068 public static Dimension getImageSize(InputStream img) 069 throws IOException 070 { 071 072 int read; 073 byte [] buf = new byte[24]; 074 if ((read=img.read(buf,0,24))>=10) { 075 if (ExtArrays.equals(buf, 0, GIF87A_SIG, 0, 6) || 076 ExtArrays.equals(buf, 0, GIF89A_SIG, 0, 6)) { 077 return new Dimension( 078 buf[7]*(2^8)+buf[6], 079 buf[9]*(2^8)+buf[8]); 080 } else if (ExtArrays.equals(buf,0,PNG_SIG,0,8)) { 081 if (read==24) { 082 return new Dimension( 083 buf[16]*2^24+buf[17]*2^16+buf[18]*2^8+buf[19], 084 buf[20]*2^24+buf[21]*2^16+buf[22]*2^8+buf[23]); 085 } else { 086 throw new RuntimeException( 087 "getImageSize: not enough data"); 088 } 089 } else if (ExtArrays.equals(buf,0,JFIF_SIG,0,4) && 090 ExtArrays.equals(buf,6,JFIF_SIG,6,4)) { 091 logger.debug("getImageSize: JPEG is not supported yet"); 092 return null; 093 } 094 logger.warn("Unrecognized signature"+ExtArrays.asList(buf)); 095 return null; 096 } else { 097 throw new RuntimeException("getImageSize: not enough data"); 098 } 099 } 100 }