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); }
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); } }