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: ImageLoaderRawCCITTFax.java 750418 2009-03-05 11:03:54Z vhennebert $ */ package org.apache.xmlgraphics.image.loader.impl; import java.io.FilterInputStream; import java.io.IOException; import java.io.InputStream; import java.util.Map; 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.TIFFImage; import org.apache.xmlgraphics.image.codec.tiff.TIFFImageDecoder; import org.apache.xmlgraphics.image.codec.util.SeekableStream; import org.apache.xmlgraphics.image.loader.Image; import org.apache.xmlgraphics.image.loader.ImageException; import org.apache.xmlgraphics.image.loader.ImageFlavor; import org.apache.xmlgraphics.image.loader.ImageInfo; import org.apache.xmlgraphics.image.loader.ImageSessionContext; 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.io.SubInputStream; /** * ImageLoader for CCITT group 3 and 4 images consumed "raw" (undecoded). Provides a * raw/undecoded stream. */ public class ImageLoaderRawCCITTFax extends AbstractImageLoader implements JPEGConstants { /** logger */ protected static Log log = LogFactory.getLog(ImageLoaderRawCCITTFax.class); /** * Main constructor. */ public ImageLoaderRawCCITTFax() { } /** {@inheritDoc} */ public ImageFlavor getTargetFlavor() { return ImageFlavor.RAW_CCITTFAX; } /** {@inheritDoc} */ public Image loadImage(ImageInfo info, Map hints, ImageSessionContext session) throws ImageException, IOException { if (!MimeConstants.MIME_TIFF.equals(info.getMimeType())) { throw new IllegalArgumentException( "ImageInfo must be from a image with MIME type: " + MimeConstants.MIME_TIFF); } int fillOrder = 1; int compression = TIFFImage.COMP_NONE; long stripOffset; long stripLength; TIFFDirectory dir; Source src = session.needSource(info.getOriginalURI()); ImageInputStream in = ImageUtil.needImageInputStream(src); in.mark(); try { SeekableStream seekable = new SeekableStreamAdapter(in); dir = new TIFFDirectory(seekable, 0); TIFFField fld; fld = dir.getField(TIFFImageDecoder.TIFF_COMPRESSION); if (fld != null) { compression = fld.getAsInt(0); switch (compression) { case TIFFImage.COMP_FAX_G3_1D: case TIFFImage.COMP_FAX_G3_2D: case TIFFImage.COMP_FAX_G4_2D: break; default: log.debug("Unsupported compression " + compression); throw new ImageException("ImageLoader doesn't support TIFF compression: " + compression); } } //Read information used for raw embedding fld = dir.getField(TIFFImageDecoder.TIFF_FILL_ORDER); if (fld != null) { fillOrder = fld.getAsInt(0); } int stripCount; fld = dir.getField(TIFFImageDecoder.TIFF_ROWS_PER_STRIP); if (fld == null) { stripCount = 1; } else { stripCount = (int) (info.getSize().getHeightPx() / fld.getAsLong(0)); } if (stripCount > 1) { log.debug("More than one strip found in TIFF image."); throw new ImageException("ImageLoader doesn't support multiple strips"); } stripOffset = dir.getField(TIFFImageDecoder.TIFF_STRIP_OFFSETS).getAsLong(0); stripLength = dir.getField(TIFFImageDecoder.TIFF_STRIP_BYTE_COUNTS).getAsLong(0); } finally { in.reset(); } in.seek(stripOffset); InputStream subin = new SubInputStream(ImageUtil.needInputStream(src), stripLength, true); if (fillOrder == 2) { //Decorate to flip bit order subin = new FillOrderChangeInputStream(subin); } ImageRawCCITTFax rawImage = new ImageRawCCITTFax(info, subin, compression); //Strip stream from source as we pass it on internally ImageUtil.removeStreams(src); return rawImage; } private static class FillOrderChangeInputStream extends FilterInputStream { protected FillOrderChangeInputStream(InputStream in) { super(in); } /** {@inheritDoc} */ public int read(byte[] b, int off, int len) throws IOException { int result = super.read(b, off, len); if (result > 0) { int endpos = off + result; for (int i = off; i < endpos; i++) { b[i] = FLIP_TABLE[b[i] & 0xff]; } } return result; } /** {@inheritDoc} */ public int read() throws IOException { int b = super.read(); if (b < 0) { return b; } else { return FLIP_TABLE[b] & 0xff; } } // Table to be used when fillOrder = 2, for flipping bytes. // Copied from XML Graphics Commons' TIFFFaxDecoder class private static final byte[] FLIP_TABLE = { 0, -128, 64, -64, 32, -96, 96, -32, 16, -112, 80, -48, 48, -80, 112, -16, 8, -120, 72, -56, 40, -88, 104, -24, 24, -104, 88, -40, 56, -72, 120, -8, 4, -124, 68, -60, 36, -92, 100, -28, 20, -108, 84, -44, 52, -76, 116, -12, 12, -116, 76, -52, 44, -84, 108, -20, 28, -100, 92, -36, 60, -68, 124, -4, 2, -126, 66, -62, 34, -94, 98, -30, 18, -110, 82, -46, 50, -78, 114, -14, 10, -118, 74, -54, 42, -86, 106, -22, 26, -102, 90, -38, 58, -70, 122, -6, 6, -122, 70, -58, 38, -90, 102, -26, 22, -106, 86, -42, 54, -74, 118, -10, 14, -114, 78, -50, 46, -82, 110, -18, 30, -98, 94, -34, 62, -66, 126, -2, 1, -127, 65, -63, 33, -95, 97, -31, 17, -111, 81, -47, 49, -79, 113, -15, 9, -119, 73, -55, 41, -87, 105, -23, 25, -103, 89, -39, 57, -71, 121, -7, 5, -123, 69, -59, 37, -91, 101, -27, 21, -107, 85, -43, 53, -75, 117, -11, 13, -115, 77, -51, 45, -83, 109, -19, 29, -99, 93, -35, 61, -67, 125, -3, 3, -125, 67, -61, 35, -93, 99, -29, 19, -109, 83, -45, 51, -77, 115, -13, 11, -117, 75, -53, 43, -85, 107, -21, 27, -101, 91, -37, 59, -69, 123, -5, 7, -121, 71, -57, 39, -89, 103, -25, 23, -105, 87, -41, 55, -73, 119, -9, 15, -113, 79, -49, 47, -81, 111, -17, 31, -97, 95, -33, 63, -65, 127, -1, }; // end } }