import com.sun.imageio.plugins.common.LZWCompressor; //导入依赖的package包/类
private void writeRowsOpt(byte[] data, int offset, int lineStride,
                          LZWCompressor compressor,
                          int dy, int ddy, int dw, int dh,
                          int numRowsWritten, int progressReportRowPeriod)
  throws IOException {
    if (DEBUG) System.out.println("Writing optimized");

    offset += dy*lineStride;
    lineStride *= ddy;
    for (int y = dy; y < dh; y += ddy) {
        if (numRowsWritten % progressReportRowPeriod == 0) {
            if (abortRequested()) {
                processWriteAborted();
                return;
            }
            processImageProgress((numRowsWritten*100.0F)/dh);
        }

        compressor.compress(data, offset, dw);
        numRowsWritten++;
        offset += lineStride;
    }
}
 

import com.sun.imageio.plugins.common.LZWCompressor; //导入依赖的package包/类
private void writeRowsOpt(byte[] data, int offset, int lineStride,
                          LZWCompressor compressor,
                          int dy, int ddy, int dw, int dh,
                          int numRowsWritten, int progressReportRowPeriod)
  throws IOException {
    if (DEBUG) System.out.println("Writing optimized");

    offset += dy*lineStride;
    lineStride *= ddy;
    for (int y = dy; y < dh; y += ddy) {
        if (numRowsWritten % progressReportRowPeriod == 0) {
            processImageProgress((numRowsWritten*100.0F)/dh);
            if (abortRequested()) {
                processWriteAborted();
                return;
            }
        }

        compressor.compress(data, offset, dw);
        numRowsWritten++;
        offset += lineStride;
    }
}
 

import com.sun.imageio.plugins.common.LZWCompressor; //导入依赖的package包/类
private void writeRows(RenderedImage image, LZWCompressor compressor,
                       int sx, int sdx, int sy, int sdy, int sw,
                       int dy, int ddy, int dw, int dh,
                       int numRowsWritten, int progressReportRowPeriod)
  throws IOException {
    if (DEBUG) System.out.println("Writing unoptimized");

    int[] sbuf = new int[sw];
    byte[] dbuf = new byte[dw];

    Raster raster =
        image.getNumXTiles() == 1 && image.getNumYTiles() == 1 ?
        image.getTile(0, 0) : image.getData();
    for (int y = dy; y < dh; y += ddy) {
        if (numRowsWritten % progressReportRowPeriod == 0) {
            if (abortRequested()) {
                processWriteAborted();
                return;
            }
            processImageProgress((numRowsWritten*100.0F)/dh);
        }

        raster.getSamples(sx, sy, sw, 1, 0, sbuf);
        for (int i = 0, j = 0; i < dw; i++, j += sdx) {
            dbuf[i] = (byte)sbuf[j];
        }
        compressor.compress(dbuf, 0, dw);
        numRowsWritten++;
        sy += sdy;
    }
}
 

import com.sun.imageio.plugins.common.LZWCompressor; //导入依赖的package包/类
private void writeRows(RenderedImage image, LZWCompressor compressor,
                       int sx, int sdx, int sy, int sdy, int sw,
                       int dy, int ddy, int dw, int dh,
                       int numRowsWritten, int progressReportRowPeriod)
  throws IOException {
    if (DEBUG) System.out.println("Writing unoptimized");

    int[] sbuf = new int[sw];
    byte[] dbuf = new byte[dw];

    Raster raster =
        image.getNumXTiles() == 1 && image.getNumYTiles() == 1 ?
        image.getTile(0, 0) : image.getData();
    for (int y = dy; y < dh; y += ddy) {
        if (numRowsWritten % progressReportRowPeriod == 0) {
            processImageProgress((numRowsWritten*100.0F)/dh);
            if (abortRequested()) {
                processWriteAborted();
                return;
            }
        }

        raster.getSamples(sx, sy, sw, 1, 0, sbuf);
        for (int i = 0, j = 0; i < dw; i++, j += sdx) {
            dbuf[i] = (byte)sbuf[j];
        }
        compressor.compress(dbuf, 0, dw);
        numRowsWritten++;
        sy += sdy;
    }
}
 

import com.sun.imageio.plugins.common.LZWCompressor; //导入依赖的package包/类
public int encode(byte[] b, int off,
                  int width, int height,
                  int[] bitsPerSample,
                  int scanlineStride) throws IOException {

    LZWCompressor lzwCompressor = new LZWCompressor(stream, 8, true);

    int samplesPerPixel = bitsPerSample.length;
    int bitsPerPixel = 0;
    for (int i = 0; i < samplesPerPixel; i++) {
        bitsPerPixel += bitsPerSample[i];
    }
    int bytesPerRow = (bitsPerPixel*width + 7)/8;

    long initialStreamPosition = stream.getStreamPosition();

    boolean usePredictor =
        predictor == BaselineTIFFTagSet.PREDICTOR_HORIZONTAL_DIFFERENCING;

    if(bytesPerRow == scanlineStride && !usePredictor) {
        lzwCompressor.compress(b, off, bytesPerRow*height);
    } else {
        byte[] rowBuf = usePredictor ? new byte[bytesPerRow] : null;
        for(int i = 0; i < height; i++) {
            if(usePredictor) {
                // Cannot modify b[] in place as it might be a data
                // array from the image being written so make a copy.
                System.arraycopy(b, off, rowBuf, 0, bytesPerRow);
                for(int j = bytesPerRow - 1; j >= samplesPerPixel; j--) {
                    rowBuf[j] -= rowBuf[j - samplesPerPixel];
                }
                lzwCompressor.compress(rowBuf, 0, bytesPerRow);
            } else {
                lzwCompressor.compress(b, off, bytesPerRow);
            }
            off += scanlineStride;
        }
    }

    lzwCompressor.flush();

    int bytesWritten =
        (int)(stream.getStreamPosition() - initialStreamPosition);

    return bytesWritten;
}