Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ /* $Id: PreloaderTIFF.java 925297 2010-03-19 16:11:15Z jeremias $ */ package org.apache.xmlgraphics.image.loader.impl; import java.io.IOException; import java.text.MessageFormat; import javax.imageio.stream.ImageInputStream; import javax.xml.transform.Source; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.xmlgraphics.image.codec.tiff.TIFFDirectory; import org.apache.xmlgraphics.image.codec.tiff.TIFFField; import org.apache.xmlgraphics.image.codec.tiff.TIFFImageDecoder; import org.apache.xmlgraphics.image.codec.util.SeekableStream; import org.apache.xmlgraphics.image.loader.ImageContext; import org.apache.xmlgraphics.image.loader.ImageException; import org.apache.xmlgraphics.image.loader.ImageInfo; import org.apache.xmlgraphics.image.loader.ImageSize; import org.apache.xmlgraphics.image.loader.SubImageNotFoundException; import org.apache.xmlgraphics.image.loader.util.ImageUtil; import org.apache.xmlgraphics.image.loader.util.SeekableStreamAdapter; import org.apache.xmlgraphics.util.MimeConstants; import org.apache.xmlgraphics.util.UnitConv; /** * Image preloader for TIFF images. * <p> * Note: The implementation relies on the TIFF codec code in Apache XML Graphics Commons for * access to the TIFF directory. */ public class PreloaderTIFF extends AbstractImagePreloader { private static Log log = LogFactory.getLog(PreloaderTIFF.class); private static final int TIFF_SIG_LENGTH = 8; /** {@inheritDoc} * @throws ImageException */ public ImageInfo preloadImage(String uri, Source src, ImageContext context) throws IOException, ImageException { if (!ImageUtil.hasImageInputStream(src)) { return null; } ImageInputStream in = ImageUtil.needImageInputStream(src); byte[] header = getHeader(in, TIFF_SIG_LENGTH); boolean supported = false; // first 2 bytes = II (little endian encoding) if (header[0] == (byte) 0x49 && header[1] == (byte) 0x49) { // look for '42' in byte 3 and '0' in byte 4 if (header[2] == 42 && header[3] == 0) { supported = true; } } // first 2 bytes == MM (big endian encoding) if (header[0] == (byte) 0x4D && header[1] == (byte) 0x4D) { // look for '42' in byte 4 and '0' in byte 3 if (header[2] == 0 && header[3] == 42) { supported = true; } } if (supported) { ImageInfo info = createImageInfo(uri, in, context); return info; } else { return null; } } private ImageInfo createImageInfo(String uri, ImageInputStream in, ImageContext context) throws IOException, ImageException { ImageInfo info = null; in.mark(); try { int pageIndex = ImageUtil.needPageIndexFromURI(uri); SeekableStream seekable = new SeekableStreamAdapter(in); TIFFDirectory dir; try { dir = new TIFFDirectory(seekable, pageIndex); } catch (IllegalArgumentException iae) { String errorMessage = MessageFormat.format("Subimage {0} does not exist.", new Object[] { new Integer(pageIndex) }); throw new SubImageNotFoundException(errorMessage); } int width = (int) dir.getFieldAsLong(TIFFImageDecoder.TIFF_IMAGE_WIDTH); int height = (int) dir.getFieldAsLong(TIFFImageDecoder.TIFF_IMAGE_LENGTH); ImageSize size = new ImageSize(); size.setSizeInPixels(width, height); int unit = 2; //inch is default if (dir.isTagPresent(TIFFImageDecoder.TIFF_RESOLUTION_UNIT)) { unit = (int) dir.getFieldAsLong(TIFFImageDecoder.TIFF_RESOLUTION_UNIT); } if (unit == 2 || unit == 3) { float xRes, yRes; TIFFField fldx = dir.getField(TIFFImageDecoder.TIFF_X_RESOLUTION); TIFFField fldy = dir.getField(TIFFImageDecoder.TIFF_Y_RESOLUTION); if (fldx == null || fldy == null) { unit = 2; xRes = context.getSourceResolution(); yRes = xRes; } else { xRes = fldx.getAsFloat(0); yRes = fldy.getAsFloat(0); } if (unit == 2) { size.setResolution(xRes, yRes); //Inch } else { size.setResolution(UnitConv.in2mm(xRes) / 10, UnitConv.in2mm(yRes) / 10); //Centimeters } } else { size.setResolution(context.getSourceResolution()); } size.calcSizeFromPixels(); if (log.isTraceEnabled()) { log.trace("TIFF image detected: " + size); } info = new ImageInfo(uri, MimeConstants.MIME_TIFF); info.setSize(size); TIFFField fld; fld = dir.getField(TIFFImageDecoder.TIFF_COMPRESSION); if (fld != null) { int compression = fld.getAsInt(0); if (log.isTraceEnabled()) { log.trace("TIFF compression: " + compression); } info.getCustomObjects().put("TIFF_COMPRESSION", new Integer(compression)); } fld = dir.getField(TIFFImageDecoder.TIFF_TILE_WIDTH); if (fld != null) { if (log.isTraceEnabled()) { log.trace("TIFF is tiled"); } info.getCustomObjects().put("TIFF_TILED", Boolean.TRUE); } int stripCount; fld = dir.getField(TIFFImageDecoder.TIFF_ROWS_PER_STRIP); if (fld == null) { stripCount = 1; } else { stripCount = (int) Math.ceil(size.getHeightPx() / (double) fld.getAsLong(0)); } if (log.isTraceEnabled()) { log.trace("TIFF has " + stripCount + " strips."); } info.getCustomObjects().put("TIFF_STRIP_COUNT", new Integer(stripCount)); try { //Check if there is a next page new TIFFDirectory(seekable, pageIndex + 1); info.getCustomObjects().put(ImageInfo.HAS_MORE_IMAGES, Boolean.TRUE); if (log.isTraceEnabled()) { log.trace("TIFF is multi-page."); } } catch (IllegalArgumentException iae) { info.getCustomObjects().put(ImageInfo.HAS_MORE_IMAGES, Boolean.FALSE); } } finally { in.reset(); } return info; } }