public static boolean compressPic(String srcFilePath, String descFilePath) {
    File file = null;
    BufferedImage src = null;
    FileOutputStream out = null;
    ImageWriter imgWrier;
    ImageWriteParam imgWriteParams;

    // 指定写图片的方式为 jpg
    imgWrier = ImageIO.getImageWritersByFormatName("jpg").next();
    imgWriteParams = new javax.imageio.plugins.jpeg.JPEGImageWriteParam(null);
    // 要使用压缩,必须指定压缩方式为MODE_EXPLICIT
    imgWriteParams.setCompressionMode(imgWriteParams.MODE_EXPLICIT);
    // 这里指定压缩的程度,参数qality是取值0~1范围内,
    imgWriteParams.setCompressionQuality((float) 0.1);
    imgWriteParams.setProgressiveMode(imgWriteParams.MODE_DISABLED);
    ColorModel colorModel = ColorModel.getRGBdefault();
    // 指定压缩时使用的色彩模式
    imgWriteParams.setDestinationType(
        new javax.imageio.ImageTypeSpecifier(
            colorModel, colorModel.createCompatibleSampleModel(16, 16)));

    try {
      if (StringUtils.isBlank(srcFilePath)) {
        return false;
      } else {
        file = new File(srcFilePath);
        src = ImageIO.read(file);
        out = new FileOutputStream(descFilePath);

        imgWrier.reset();
        // 必须先指定 out值,才能调用write方法, ImageOutputStream可以通过任何 OutputStream构造
        imgWrier.setOutput(ImageIO.createImageOutputStream(out));
        // 调用write方法,就可以向输入流写图片
        imgWrier.write(null, new IIOImage(src, null, null), imgWriteParams);
        out.flush();
        out.close();
      }
    } catch (Exception e) {
      e.printStackTrace();
      return false;
    }
    return true;
  }
Esempio n. 2
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  private void readHeader() throws IOException {
    if (gotHeader) {
      iis.seek(128);
      return;
    }

    metadata = new PCXMetadata();

    manufacturer = iis.readByte(); // manufacturer
    if (manufacturer != MANUFACTURER) throw new IllegalStateException("image is not a PCX file");
    metadata.version = iis.readByte(); // version
    encoding = iis.readByte(); // encoding
    if (encoding != ENCODING)
      throw new IllegalStateException("image is not a PCX file, invalid encoding " + encoding);

    metadata.bitsPerPixel = iis.readByte();

    metadata.xmin = iis.readShort();
    metadata.ymin = iis.readShort();
    xmax = iis.readShort();
    ymax = iis.readShort();

    metadata.hdpi = iis.readShort();
    metadata.vdpi = iis.readShort();

    iis.readFully(smallPalette);

    iis.readByte(); // reserved

    colorPlanes = iis.readByte();
    bytesPerLine = iis.readShort();
    paletteType = iis.readShort();

    metadata.hsize = iis.readShort();
    metadata.vsize = iis.readShort();

    iis.skipBytes(54); // skip filler

    width = xmax - metadata.xmin + 1;
    height = ymax - metadata.ymin + 1;

    if (colorPlanes == 1) {
      if (paletteType == PALETTE_GRAYSCALE) {
        ColorSpace cs = ColorSpace.getInstance(ColorSpace.CS_GRAY);
        int[] nBits = {8};
        colorModel =
            new ComponentColorModel(
                cs, nBits, false, false, Transparency.OPAQUE, DataBuffer.TYPE_BYTE);
        sampleModel =
            new ComponentSampleModel(DataBuffer.TYPE_BYTE, width, height, 1, width, new int[] {0});
      } else {
        if (metadata.bitsPerPixel == 8) {
          // read palette from end of file, then reset back to image data
          iis.mark();

          if (iis.length() == -1) {
            // read until eof, and work backwards
            while (iis.read() != -1) ;
            iis.seek(iis.getStreamPosition() - 256 * 3 - 1);
          } else {
            iis.seek(iis.length() - 256 * 3 - 1);
          }

          int palletteMagic = iis.read();
          if (palletteMagic != 12)
            processWarningOccurred(
                "Expected palette magic number 12; instead read "
                    + palletteMagic
                    + " from this image.");

          iis.readFully(largePalette);
          iis.reset();

          colorModel = new IndexColorModel(metadata.bitsPerPixel, 256, largePalette, 0, false);
          sampleModel = colorModel.createCompatibleSampleModel(width, height);
        } else {
          int msize = metadata.bitsPerPixel == 1 ? 2 : 16;
          colorModel = new IndexColorModel(metadata.bitsPerPixel, msize, smallPalette, 0, false);
          sampleModel = colorModel.createCompatibleSampleModel(width, height);
        }
      }
    } else {
      ColorSpace cs = ColorSpace.getInstance(ColorSpace.CS_sRGB);
      int[] nBits = {8, 8, 8};
      colorModel =
          new ComponentColorModel(
              cs, nBits, false, false, Transparency.OPAQUE, DataBuffer.TYPE_BYTE);
      sampleModel =
          new ComponentSampleModel(
              DataBuffer.TYPE_BYTE,
              width,
              height,
              1,
              width * colorPlanes,
              new int[] {0, width, width * 2});
    }

    originalSampleModel = sampleModel;
    originalColorModel = colorModel;

    gotHeader = true;
  }