←Select platform

StartDecompress Method

Summary
Initializes the buffered decompression engine.
Syntax
C#
Objective-C
C++/CLI
Java
Python
public object StartDecompress( 
   CodecsStartDecompressOptions options 
) 
- (nullable NSObject *)startDecompress:(LTCodecsStartDecompressOptions *)decompressOptions error:(NSError **)error 
public Object startDecompress(CodecsStartDecompressOptions options) 
public: 
Object^ StartDecompress(  
   CodecsStartDecompressOptions options 
)  
def StartDecompress(self,options): 

Parameters

options
Provides input parameters for the decompression process.

Return Value

An object that identifies the decompression process. This same object must be passed to the Decompress and StopDecompress methods.

Remarks

Initializes the buffered decompression engine. The decompression is then carried out using the Decompress method. It is ended by the StopDecompress method.

Currently, raw JPEG must contain all the Huffman tables encoded. That is, it must be a readable JPEG file.

Example
C#
Java
using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing; 
using Leadtools.ImageProcessing.Color; 
using Leadtools.Svg; 
 
 
// This sample loads raw data from a PackBits TIF file 
// PackBits.tif is a 24-bit tif packbits compressed file 
// PackBits.tif has 46 strips of packbits data 
// The strip information is obtained by reading the TIF tags TAG_STRIPOFFSETS and TAG_STRIPBYTECOUNTS 
// The strips are directly read and fed to the Compress method 
void LoadRawPackbitsStrips(string packTifFile) 
{ 
   RasterCodecs codecs = new RasterCodecs(); 
 
   string destFileName = Path.Combine(LEAD_VARS.ImagesDir, "Decompress.bmp"); 
 
   CodecsImageInfo imageInfo = codecs.GetInformation(packTifFile, false); 
 
   // StartDecompress 
   CodecsStartDecompressOptions options = CodecsStartDecompressOptions.Empty; 
   options.DataType = CodecsStartDecompressDataType.Strips; 
   options.Format = RasterImageFormat.RawPackBits; 
   options.Width = imageInfo.Width; 
   options.Height = imageInfo.Height; 
   options.BitsPerPixel = imageInfo.BitsPerPixel; 
   options.LeastSignificantBitFirst = false; 
   options.Pad4 = false; 
   options.PlanarConfiguration = CodecsPlanarConfiguration.PlanarFormat; 
   options.ViewPerspective = imageInfo.ViewPerspective; 
   options.RawOrder = imageInfo.Order; 
   options.LoadOrder = CodecsLoadByteOrder.BgrOrGray; 
   options.XResolution = imageInfo.XResolution; 
   options.YResolution = imageInfo.YResolution; 
   options.TiffPhotometricInterpretation = CodecsTiffPhotometricInterpretation.Rgb; 
   options.SetColorMask(options.GetColorMask()); 
   options.SetPalette(options.GetPalette()); 
   options.UsePalette = false; 
 
   object decompressObject = codecs.StartDecompress(options); 
 
   // Decompress 
 
   const int TAG_STRIPOFFSETS = 0x111; 
   const int TAG_STRIPBYTECOUNTS = 0x117; 
   const int TAG_ROWSPERSTRIP = 0x116; 
   const int MAX_STRIPS = 1000; 
 
   int[] stripOffsets = new int[MAX_STRIPS]; 
   int[] stripSizes = new int[MAX_STRIPS]; 
   int[] rowsPerStripBuffer = new int[1]; 
 
   int maxIndex = ReadTag(codecs, packTifFile, TAG_STRIPOFFSETS, stripOffsets); 
   ReadTag(codecs, packTifFile, TAG_STRIPBYTECOUNTS, stripSizes); 
   ReadTag(codecs, packTifFile, TAG_ROWSPERSTRIP, rowsPerStripBuffer); 
   int rowsPerStrip = rowsPerStripBuffer[0]; 
 
   FileStream fs = File.OpenRead(packTifFile); 
 
   const int row = 0; // Note: this parameter is ignored for strips 
   const int column = 0; // Column offset of tile 
   for (int index = 0; index < maxIndex; index++) 
   { 
      // seek to the first strip 
      fs.Seek(stripOffsets[index], SeekOrigin.Begin); 
 
      byte[] buffer = new byte[stripSizes[index]]; 
      fs.Read(buffer, 0, buffer.Length); 
 
      // Calculate the height of uncompressed strip/tile 
      int height = rowsPerStrip; 
      if (index == (maxIndex - 1)) 
      { 
         // fewer rows per strip 
         height = imageInfo.Height - (maxIndex - 1) * rowsPerStrip; 
      } 
 
      codecs.Decompress( 
         decompressObject, 
         buffer, 
         0, 
         buffer.Length, 
         imageInfo.Width, 
         height, 
         row, 
         column, 
         CodecsDecompressDataFlags.Complete); 
   } 
 
   fs.Close(); 
 
   // StopDecompress 
   RasterImage image = codecs.StopDecompress(decompressObject); 
 
   // 'image' contains the uncompressed image 
   codecs.Save(image, destFileName, RasterImageFormat.Bmp, 24); 
   image.Dispose(); 
 
   // Clean up 
   codecs.Dispose(); 
} 
 
// Returns maximum index 
int ReadTag(RasterCodecs codecs, string fileName, int tagId, int[] stripArray) 
{ 
   RasterTagMetadata tag = codecs.ReadTag(fileName, 1, tagId); 
   int[] data = tag.ToInt32(); 
   data.CopyTo(stripArray, 0); 
   return tag.Count; 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\LEADTOOLS23\Resources\Images"; 
} 
 
import java.io.*; 
import java.net.*; 
import java.nio.file.Paths; 
import java.util.*; 
import java.time.Instant; 
import java.time.Duration; 
 
import org.junit.*; 
import org.junit.runner.JUnitCore; 
import org.junit.runner.Result; 
import org.junit.runner.notification.Failure; 
import static org.junit.Assert.*; 
 
import leadtools.*; 
import leadtools.codecs.*; 
import leadtools.codecs.RasterCodecs.FeedCallbackThunk; 
import leadtools.drawing.internal.*; 
import leadtools.imageprocessing.*; 
import leadtools.imageprocessing.color.ChangeIntensityCommand; 
import leadtools.svg.*; 
 
 
// This sample loads raw data from a PackBits TIF file 
// PackBits.tif is a 24-bit tif packbits compressed file 
// PackBits.tif has 46 strips of packbits data 
// The strip information is obtained by reading the TIF tags TAG_STRIPOFFSETS 
// and TAG_STRIPBYTECOUNTS 
// The strips are directly read and fed to the Compress method 
public void loadRawPackbitsStripsExample() throws IOException { 
   final String LEAD_VARS_IMAGES_DIR = "C:\\LEADTOOLS23\\Resources\\Images"; 
   String packTifFile = combine(LEAD_VARS_IMAGES_DIR, "packbits.tif"); 
   RasterCodecs codecs = new RasterCodecs(); 
 
   String destFileName = combine(LEAD_VARS_IMAGES_DIR, "Decompress.bmp"); 
 
   CodecsImageInfo imageInfo = codecs.getInformation(packTifFile, false); 
 
   // StartDecompress 
   CodecsStartDecompressOptions options = CodecsStartDecompressOptions.getEmpty(); 
   options.setDataType(CodecsStartDecompressDataType.STRIPS); 
   options.setFormat(RasterImageFormat.RAW_PACKBITS); 
   options.setWidth(imageInfo.getWidth()); 
   options.setHeight(imageInfo.getHeight()); 
   options.setBitsPerPixel(imageInfo.getBitsPerPixel()); 
   options.setLeastSignificantBitFirst(false); 
   options.setPad4(false); 
   options.setPlanarConfiguration(CodecsPlanarConfiguration.PLANAR_FORMAT); 
   options.setViewPerspective(imageInfo.getViewPerspective()); 
   options.setRawOrder(imageInfo.getOrder()); 
   options.setLoadOrder(CodecsLoadByteOrder.BGR_OR_GRAY); 
   options.setXResolution(imageInfo.getXResolution()); 
   options.setYResolution(imageInfo.getYResolution()); 
   options.setTiffPhotometricInterpretation(CodecsTiffPhotometricInterpretation.RGB); 
   options.setColorMask(options.getColorMask()); 
   options.setPalette(options.getPalette()); 
   options.setUsePalette(false); 
 
   Object decompressObject = codecs.startDecompress(options); 
 
   // Decompress 
   final int TAG_STRIPOFFSETS = 0x111; 
   final int TAG_STRIPBYTECOUNTS = 0x117; 
   final int TAG_ROWSPERSTRIP = 0x116; 
   final int MAX_STRIPS = 1000; 
 
   int[] stripOffsets = new int[MAX_STRIPS]; 
   int[] stripSizes = new int[MAX_STRIPS]; 
   int[] rowsPerStripBuffer = new int[1]; 
 
   int maxIndex = readTag(codecs, packTifFile, TAG_STRIPOFFSETS, stripOffsets); 
   readTag(codecs, packTifFile, TAG_STRIPBYTECOUNTS, stripSizes); 
   readTag(codecs, packTifFile, TAG_ROWSPERSTRIP, rowsPerStripBuffer); 
   int rowsPerStrip = rowsPerStripBuffer[0]; 
 
   ILeadStream packTifStream = LeadStreamFactory.create(packTifFile); 
 
   final int row = 0; // Note: this parameter is ignored for strips 
   final int column = 0; // Column offset of tile 
   for (int index = 0; index < maxIndex; index++) { 
      // seek to the first strip 
      packTifStream.seek(LeadSeekOrigin.BEGIN, stripOffsets[index]); 
 
      byte[] buffer = new byte[stripSizes[index]]; 
      packTifStream.read(buffer, buffer.length); 
 
      // Calculate the height of uncompressed strip/tile 
      int height = rowsPerStrip; 
      if (index == (maxIndex - 1)) { 
         // fewer rows per strip 
         height = imageInfo.getHeight() - (maxIndex - 1) * rowsPerStrip; 
      } 
 
      codecs.decompress( 
            decompressObject, 
            buffer, 
            0, 
            buffer.length, 
            imageInfo.getWidth(), 
            height, 
            row, 
            column, 
            CodecsDecompressDataFlags.COMPLETE); 
   } 
 
   packTifStream.close(); 
 
   // StopDecompress 
   RasterImage image = codecs.stopDecompress(decompressObject); 
 
   // 'image' contains the uncompressed image 
   codecs.save(image, destFileName, RasterImageFormat.BMP, 24); 
   image.dispose(); 
 
   // Clean up 
   codecs.dispose(); 
} 
 
// Returns maximum index 
int readTag(RasterCodecs codecs, String fileName, int tagId, int[] stripArray) throws IOException { 
   ILeadStream fileStream = LeadStreamFactory.create(fileName); 
   RasterTagMetadata tag = codecs.readTag(fileStream, 1, tagId); 
   int[] data = tag.toInt32(); 
   for (int i = 0; i < data.length; i++) { 
      stripArray[i] = data[i]; 
   } 
   fileStream.close(); 
   return tag.getCount(); 
} 
Requirements

Target Platforms

Help Version 23.0.2024.2.29
Products | Support | Contact Us | Intellectual Property Notices
© 1991-2024 LEAD Technologies, Inc. All Rights Reserved.

Leadtools.Codecs Assembly

Products | Support | Contact Us | Intellectual Property Notices
© 1991-2023 LEAD Technologies, Inc. All Rights Reserved.