Exemplo n.º 1
0
  private void readGenericRegionFlags() throws IOException {
    /** extract text region Segment flags */
    short genericRegionFlagsField = decoder.readByte();

    genericRegionFlags.setFlags(genericRegionFlagsField);

    if (JBIG2StreamDecoder.debug)
      System.out.println("generic region Segment flags = " + genericRegionFlagsField);
  }
Exemplo n.º 2
0
  public void readSegment() throws IOException, JBIG2Exception {

    if (JBIG2StreamDecoder.debug) System.out.println("==== Reading Immediate Generic Region ====");

    super.readSegment();

    /** read text region Segment flags */
    readGenericRegionFlags();

    boolean useMMR = genericRegionFlags.getFlagValue(GenericRegionFlags.MMR) != 0;
    int template = genericRegionFlags.getFlagValue(GenericRegionFlags.GB_TEMPLATE);

    short[] genericBAdaptiveTemplateX = new short[4];
    short[] genericBAdaptiveTemplateY = new short[4];

    if (!useMMR) {
      if (template == 0) {
        genericBAdaptiveTemplateX[0] = readATValue();
        genericBAdaptiveTemplateY[0] = readATValue();
        genericBAdaptiveTemplateX[1] = readATValue();
        genericBAdaptiveTemplateY[1] = readATValue();
        genericBAdaptiveTemplateX[2] = readATValue();
        genericBAdaptiveTemplateY[2] = readATValue();
        genericBAdaptiveTemplateX[3] = readATValue();
        genericBAdaptiveTemplateY[3] = readATValue();
      } else {
        genericBAdaptiveTemplateX[0] = readATValue();
        genericBAdaptiveTemplateY[0] = readATValue();
      }

      arithmeticDecoder.resetGenericStats(template, null);
      arithmeticDecoder.start();
    }

    boolean typicalPredictionGenericDecodingOn =
        genericRegionFlags.getFlagValue(GenericRegionFlags.TPGDON) != 0;
    int length = segmentHeader.getSegmentDataLength();

    if (length == -1) {
      /**
       * length of data is unknown, so it needs to be determined through examination of the data.
       * See 7.2.7 - Segment data length of the JBIG2 specification.
       */
      unknownLength = true;

      short match1;
      short match2;

      if (useMMR) {
        // look for 0x00 0x00 (0, 0)

        match1 = 0;
        match2 = 0;
      } else {
        // look for 0xFF 0xAC (255, 172)

        match1 = 255;
        match2 = 172;
      }

      int bytesRead = 0;
      while (true) {
        short bite1 = decoder.readByte();
        bytesRead++;

        if (bite1 == match1) {
          short bite2 = decoder.readByte();
          bytesRead++;

          if (bite2 == match2) {
            length = bytesRead - 2;
            break;
          }
        }
      }

      decoder.movePointer(-bytesRead);
    }

    JBIG2Bitmap bitmap =
        new JBIG2Bitmap(
            regionBitmapWidth, regionBitmapHeight, arithmeticDecoder, huffmanDecoder, mmrDecoder);
    bitmap.clear(0);
    bitmap.readBitmap(
        useMMR,
        template,
        typicalPredictionGenericDecodingOn,
        false,
        null,
        genericBAdaptiveTemplateX,
        genericBAdaptiveTemplateY,
        useMMR ? 0 : length - 18);

    if (inlineImage) {
      PageInformationSegment pageSegment =
          decoder.findPageSegement(segmentHeader.getPageAssociation());
      JBIG2Bitmap pageBitmap = pageSegment.getPageBitmap();

      int extCombOp = regionFlags.getFlagValue(RegionFlags.EXTERNAL_COMBINATION_OPERATOR);

      if (pageSegment.getPageBitmapHeight() == -1
          && regionBitmapYLocation + regionBitmapHeight > pageBitmap.getHeight()) {
        pageBitmap.expand(
            regionBitmapYLocation + regionBitmapHeight,
            pageSegment
                .getPageInformationFlags()
                .getFlagValue(PageInformationFlags.DEFAULT_PIXEL_VALUE));
      }

      pageBitmap.combine(bitmap, regionBitmapXLocation, regionBitmapYLocation, extCombOp);
    } else {
      bitmap.setBitmapNumber(getSegmentHeader().getSegmentNumber());
      decoder.appendBitmap(bitmap);
    }

    if (unknownLength) {
      decoder.movePointer(4);
    }
  }