JDK8/Java8源码在线阅读

/*
 * Copyright (c) 2003, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package com.sun.imageio.plugins.wbmp;

import java.awt.Point;
import java.awt.Rectangle;
import java.awt.image.ColorModel;
import java.awt.image.DataBuffer;
import java.awt.image.DataBufferByte;
import java.awt.image.IndexColorModel;
import java.awt.image.MultiPixelPackedSampleModel;
import java.awt.image.Raster;
import java.awt.image.RenderedImage;
import java.awt.image.SampleModel;
import java.awt.image.WritableRaster;

import java.io.IOException;

import javax.imageio.IIOImage;
import javax.imageio.IIOException;
import javax.imageio.ImageTypeSpecifier;
import javax.imageio.ImageWriteParam;
import javax.imageio.ImageWriter;
import javax.imageio.metadata.IIOMetadata;
import javax.imageio.metadata.IIOMetadataFormatImpl;
import javax.imageio.metadata.IIOInvalidTreeException;
import javax.imageio.spi.ImageWriterSpi;
import javax.imageio.stream.ImageOutputStream;

import com.sun.imageio.plugins.common.I18N;

/**
 * The Java Image IO plugin writer for encoding a binary RenderedImage into
 * a WBMP format.
 *
 * The encoding process may clip, subsample using the parameters
 * specified in the <code>ImageWriteParam</code>.
 *
 * @see com.sun.media.imageio.plugins.WBMPImageWriteParam
 */
public class WBMPImageWriter extends ImageWriter {
    /** The output stream to write into */
    private ImageOutputStream stream = null;

    // Get the number of bits required to represent an int.
    private static int getNumBits(int intValue) {
        int numBits = 32;
        int mask = 0x80000000;
        while(mask != 0 && (intValue & mask) == 0) {
            numBits--;
            mask >>>= 1;
        }
        return numBits;
    }

    // Convert an int value to WBMP multi-byte format.
    private static byte[] intToMultiByte(int intValue) {
        int numBitsLeft = getNumBits(intValue);
        byte[] multiBytes = new byte[(numBitsLeft + 6)/7];

        int maxIndex = multiBytes.length - 1;
        for(int b = 0; b <= maxIndex; b++) {
            multiBytes[b] = (byte)((intValue >>> ((maxIndex - b)*7))&0x7f);
            if(b != maxIndex) {
                multiBytes[b] |= (byte)0x80;
            }
        }

        return multiBytes;
    }

    /** Constructs <code>WBMPImageWriter</code> based on the provided
     *  <code>ImageWriterSpi</code>.
     */
    public WBMPImageWriter(ImageWriterSpi originator) {
        super(originator);
    }

    public void setOutput(Object output) {
        super.setOutput(output); // validates output
        if (output != null) {
            if (!(output instanceof ImageOutputStream))
                throw new IllegalArgumentException(I18N.getString("WBMPImageWriter"));
            this.stream = (ImageOutputStream)output;
        } else
            this.stream = null;
    }

    public IIOMetadata getDefaultStreamMetadata(ImageWriteParam param) {
        return null;
    }

    public IIOMetadata getDefaultImageMetadata(ImageTypeSpecifier imageType,
                                               ImageWriteParam param) {
        WBMPMetadata meta = new WBMPMetadata();
        meta.wbmpType = 0; // default wbmp level
        return meta;
    }

    public IIOMetadata convertStreamMetadata(IIOMetadata inData,
                                             ImageWriteParam param) {
        return null;
    }

    public IIOMetadata convertImageMetadata(IIOMetadata metadata,
                                            ImageTypeSpecifier type,
                                            ImageWriteParam param) {
        return null;
    }

    public boolean canWriteRasters() {
        return true;
    }

    public void write(IIOMetadata streamMetadata,
                      IIOImage image,
                      ImageWriteParam param) throws IOException {

        if (stream == null) {
            throw new IllegalStateException(I18N.getString("WBMPImageWriter3"));
        }

        if (image == null) {
            throw new IllegalArgumentException(I18N.getString("WBMPImageWriter4"));
        }

        clearAbortRequest();
        processImageStarted(0);
        if (param == null)
            param = getDefaultWriteParam();

        RenderedImage input = null;
        Raster inputRaster = null;
        boolean writeRaster = image.hasRaster();
        Rectangle sourceRegion = param.getSourceRegion();
        SampleModel sampleModel = null;

        if (writeRaster) {
            inputRaster = image.getRaster();
            sampleModel = inputRaster.getSampleModel();
        } else {
            input = image.getRenderedImage();
            sampleModel = input.getSampleModel();

            inputRaster = input.getData();
        }

        checkSampleModel(sampleModel);
        if (sourceRegion == null)
            sourceRegion = inputRaster.getBounds();
        else
            sourceRegion = sourceRegion.intersection(inputRaster.getBounds());

        if (sourceRegion.isEmpty())
            throw new RuntimeException(I18N.getString("WBMPImageWriter1"));

        int scaleX = param.getSourceXSubsampling();
        int scaleY = param.getSourceYSubsampling();
        int xOffset = param.getSubsamplingXOffset();
        int yOffset = param.getSubsamplingYOffset();

        sourceRegion.translate(xOffset, yOffset);
        sourceRegion.width -= xOffset;
        sourceRegion.height -= yOffset;

        int minX = sourceRegion.x / scaleX;
        int minY = sourceRegion.y / scaleY;
        int w = (sourceRegion.width + scaleX - 1) / scaleX;
        int h = (sourceRegion.height + scaleY - 1) / scaleY;

        Rectangle destinationRegion = new Rectangle(minX, minY, w, h);
        sampleModel = sampleModel.createCompatibleSampleModel(w, h);

        SampleModel destSM= sampleModel;

        // If the data are not formatted nominally then reformat.
        if(sampleModel.getDataType() != DataBuffer.TYPE_BYTE ||
           !(sampleModel instanceof MultiPixelPackedSampleModel) ||
           ((MultiPixelPackedSampleModel)sampleModel).getDataBitOffset() != 0) {
           destSM =
                new MultiPixelPackedSampleModel(DataBuffer.TYPE_BYTE,
                                                w, h, 1,
                                                w + 7 >> 3, 0);
        }

        if (!destinationRegion.equals(sourceRegion)) {
            if (scaleX == 1 && scaleY == 1)
                inputRaster = inputRaster.createChild(inputRaster.getMinX(),
                                                      inputRaster.getMinY(),
                                                      w, h, minX, minY, null);
            else {
                WritableRaster ras = Raster.createWritableRaster(destSM,
                                                                 new Point(minX, minY));

                byte[] data = ((DataBufferByte)ras.getDataBuffer()).getData();

                for(int j = minY, y = sourceRegion.y, k = 0;
                    j < minY + h; j++, y += scaleY) {

                    for (int i = 0, x = sourceRegion.x;
                        i <w; i++, x +=scaleX) {
                        int v = inputRaster.getSample(x, y, 0);
                        data[k + (i >> 3)] |= v << (7 - (i & 7));
                    }
                    k += w + 7 >> 3;
                }
                inputRaster = ras;
            }
        }

        // If the data are not formatted nominally then reformat.
        if(!destSM.equals(inputRaster.getSampleModel())) {
            WritableRaster raster =
                Raster.createWritableRaster(destSM,
                                            new Point(inputRaster.getMinX(),
                                                      inputRaster.getMinY()));
            raster.setRect(inputRaster);
            inputRaster = raster;
        }

        // Check whether the image is white-is-zero.
        boolean isWhiteZero = false;
        if(!writeRaster && input.getColorModel() instanceof IndexColorModel) {
            IndexColorModel icm = (IndexColorModel)input.getColorModel();
            isWhiteZero = icm.getRed(0) > icm.getRed(1);
        }

        // Get the line stride, bytes per row, and data array.
        int lineStride =
            ((MultiPixelPackedSampleModel)destSM).getScanlineStride();
        int bytesPerRow = (w + 7)/8;
        byte[] bdata = ((DataBufferByte)inputRaster.getDataBuffer()).getData();

        // Write WBMP header.
        stream.write(0); // TypeField
        stream.write(0); // FixHeaderField
        stream.write(intToMultiByte(w)); // width
        stream.write(intToMultiByte(h)); // height

        // Write the data.
        if(!isWhiteZero && lineStride == bytesPerRow) {
            // Write the entire image.
            stream.write(bdata, 0, h * bytesPerRow);
            processImageProgress(100.0F);
        } else {
            // Write the image row-by-row.
            int offset = 0;
            if(!isWhiteZero) {
                // Black-is-zero
                for(int row = 0; row < h; row++) {
                    if (abortRequested())
                        break;
                    stream.write(bdata, offset, bytesPerRow);
                    offset += lineStride;
                    processImageProgress(100.0F * row / h);
                }
            } else {

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