- width
- The image being compressed width in pixels.
- height
- The image being compressed height in pixels.
- bitsPerPixel
- The image being compressed bits/pixel value.
- order
- The image being compressed byte order.
- viewPerspective
- The image being compressed view perspective value.
- inputDataLength
- Size in bytes of the input image data.
- outputData
- Array of bytes which will be filled with the compressed data.
- outputDataIndex
- Index into outputData where the compressed data should be inserted.
- outputDataLength
- Size of outputData in bytes.
- compression
Type of compression to use. Valid values are:
Value Meaning CodecsCompression.Cmp LEAD CMP compression format CodecsCompression.Jpeg444 JPEG File Interchange Format using YUV 4:4:4 color spacing CodecsCompression.Jpeg422 JPEG File Interchange Format using YUV 4:2:2 color spacing CodecsCompression.Jpeg411 JPEG File Interchange Format using YUV 4:1:1 color spacing CodecsCompression.TifJpeg444 JPEG JTIF using YUV 4:4:4 color spacing CodecsCompression.TifJpeg422 JPEG JTIF using YUV 4:2:2 color spacing CodecsCompression.TifJpeg411 JPEG JTIF using YUV 4:1:1 color spacing CodecsCompression.Lead0 LEAD 1 bit, lossless compression CodecsCompression.Lead1 LEAD 1 bit, excellent compression CodecsCompression.TiffCcitt TIFF CCITT CodecsCompression.TiffCcittG3Fax1Dim CCITT Group 3 one dimensional CodecsCompression.TiffCcittG3Fax2Dim CCITT Group 3 two dimensional CodecsCompression.TiffCcittG4Fax CCITT Group 4 two dimensional
- callback
- The callback method responsible for writing or handling the compressed data.
Visual Basic (Declaration) | |
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Overloads Public Sub StartCompress( _ ByVal width As Integer, _ ByVal height As Integer, _ ByVal bitsPerPixel As Integer, _ ByVal order As RasterByteOrder, _ ByVal viewPerspective As RasterViewPerspective, _ ByVal inputDataLength As Integer, _ ByVal outputData() As Byte, _ ByVal outputDataIndex As Integer, _ ByVal outputDataLength As Integer, _ ByVal compression As CodecsCompression, _ ByVal callback As CodecsCompressDataCallback _ ) |
Visual Basic (Usage) | Copy Code |
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Dim instance As RasterCodecs Dim width As Integer Dim height As Integer Dim bitsPerPixel As Integer Dim order As RasterByteOrder Dim viewPerspective As RasterViewPerspective Dim inputDataLength As Integer Dim outputData() As Byte Dim outputDataIndex As Integer Dim outputDataLength As Integer Dim compression As CodecsCompression Dim callback As CodecsCompressDataCallback instance.StartCompress(width, height, bitsPerPixel, order, viewPerspective, inputDataLength, outputData, outputDataIndex, outputDataLength, compression, callback) |
C# | |
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public void StartCompress( int width, int height, int bitsPerPixel, RasterByteOrder order, RasterViewPerspective viewPerspective, int inputDataLength, byte[] outputData, int outputDataIndex, int outputDataLength, CodecsCompression compression, CodecsCompressDataCallback callback ) |
C++/CLI | |
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public: void StartCompress( int width, int height, int bitsPerPixel, RasterByteOrder order, RasterViewPerspective viewPerspective, int inputDataLength, array<byte>^ outputData, int outputDataIndex, int outputDataLength, CodecsCompression compression, CodecsCompressDataCallback^ callback ) |
Parameters
- width
- The image being compressed width in pixels.
- height
- The image being compressed height in pixels.
- bitsPerPixel
- The image being compressed bits/pixel value.
- order
- The image being compressed byte order.
- viewPerspective
- The image being compressed view perspective value.
- inputDataLength
- Size in bytes of the input image data.
- outputData
- Array of bytes which will be filled with the compressed data.
- outputDataIndex
- Index into outputData where the compressed data should be inserted.
- outputDataLength
- Size of outputData in bytes.
- compression
Type of compression to use. Valid values are:
Value Meaning CodecsCompression.Cmp LEAD CMP compression format CodecsCompression.Jpeg444 JPEG File Interchange Format using YUV 4:4:4 color spacing CodecsCompression.Jpeg422 JPEG File Interchange Format using YUV 4:2:2 color spacing CodecsCompression.Jpeg411 JPEG File Interchange Format using YUV 4:1:1 color spacing CodecsCompression.TifJpeg444 JPEG JTIF using YUV 4:4:4 color spacing CodecsCompression.TifJpeg422 JPEG JTIF using YUV 4:2:2 color spacing CodecsCompression.TifJpeg411 JPEG JTIF using YUV 4:1:1 color spacing CodecsCompression.Lead0 LEAD 1 bit, lossless compression CodecsCompression.Lead1 LEAD 1 bit, excellent compression CodecsCompression.TiffCcitt TIFF CCITT CodecsCompression.TiffCcittG3Fax1Dim CCITT Group 3 one dimensional CodecsCompression.TiffCcittG3Fax2Dim CCITT Group 3 two dimensional CodecsCompression.TiffCcittG4Fax CCITT Group 4 two dimensional - callback
- The callback method responsible for writing or handling the compressed data.
This example demonstrates low-level image compression using StartCompress(Int32,Int32,Int32,RasterByteOrder,RasterViewPerspective,Int32,Byte[],Int32,Int32,CodecsCompression,CodecsCompressDataCallback), Compress(Byte[],Int32) and StopCompress. The callback method for writing the output is included at the end of the example
Visual Basic | Copy Code |
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Public Sub CompressExample() Dim codecs As RasterCodecs = New RasterCodecs() Dim srcFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "Image1.cmp") Dim destFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "Image1_CompressData.cmp") ' Load the image to at 24-bits per pixel Dim image As RasterImage = codecs.Load(srcFileName, 24, CodecsLoadByteOrder.Bgr, 1, 1) If image.ViewPerspective <> RasterViewPerspective.TopLeft Then image.ChangeViewPerspective(RasterViewPerspective.TopLeft) End If ' Create the output file _compressStream = File.Create(destFileName) ' Calculate the bytes per line in the input buffer, without padding Dim lineBytes As Integer = image.Width * 3 ' Allocate a buffer for the incoming uncompressed data. Note that we ' are compressing 16 lines at a time. You should always use multiples of 16 Dim inBuffer As Byte() = New Byte(16 * lineBytes - 1) {} ' Allocate an output buffer. This is where the compressed data will ' go. Note that this allocates 1024-byte packets. Dim outBuffer As Byte() = New Byte(1023) {} ' Lock down the image image.Access() ' Initialize the compression engine codecs.Options.Jpeg.Save.CmpQualityFactorPredefined = CodecsCmpQualityFactorPredefined.QualityAndSize codecs.StartCompress(image.Width, image.Height, image.BitsPerPixel, image.Order, image.ViewPerspective, 16 * lineBytes, outBuffer, 0, outBuffer.Length, CodecsCompression.Cmp, AddressOf MyCodecsCompressDataCallback) ' Compress the data Dim i As Integer = 0 Do While i < image.Height ' i is incremented at the end ' Compression of the 16-line chunk starts here Dim j As Integer = 0 Dim inBufferIndex As Integer = 0 Do While (i + j) < image.Height AndAlso j < 16 ' Get one line at time image.GetRow(i + j, inBuffer, inBufferIndex, lineBytes) ' Move to next line inBufferIndex += lineBytes j += 1 Loop ' This is the main function that will do the actual Compression codecs.Compress(inBuffer, 0) i += 16 Loop ' Reset the compression engine codecs.StopCompress() ' Release the image and close the file image.Release() _compressStream.Close() ' Clean up codecs.Dispose() End Sub Private _compressStream As FileStream Private _compressBuffer As Byte() Private Function MyCodecsCompressDataCallback(ByVal width As Integer, ByVal height As Integer, ByVal bitsPerPixel As Integer, ByVal order As RasterByteOrder, ByVal viewPerspective As RasterViewPerspective, ByVal buffer As RasterNativeBuffer) As Boolean ' Write data to the file If _compressBuffer Is Nothing OrElse _compressBuffer.Length < buffer.Length Then _compressBuffer = New Byte(CType(buffer.Length, Integer) - 1) {} End If Marshal.Copy(buffer.Data, _compressBuffer, 0, CType(buffer.Length, Integer)) _compressStream.Write(_compressBuffer, 0, CType(buffer.Length, Integer)) Return True End Function Public NotInheritable Class LEAD_VARS Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images" End Class |
C# | Copy Code |
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public void CompressExample() { RasterCodecs codecs = new RasterCodecs(); string srcFileName = Path.Combine(LEAD_VARS.ImagesDir, "Image1.cmp"); string destFileName = Path.Combine(LEAD_VARS.ImagesDir, "Image1_CompressData.cmp"); // Load the image to at 24-bits per pixel RasterImage image = codecs.Load(srcFileName, 24, CodecsLoadByteOrder.Bgr, 1, 1); if(image.ViewPerspective != RasterViewPerspective.TopLeft) image.ChangeViewPerspective(RasterViewPerspective.TopLeft); // Create the output file _compressStream = File.Create(destFileName); // Calculate the bytes per line in the input buffer, without padding int lineBytes = image.Width * 3; // Allocate a buffer for the incoming uncompressed data. Note that we // are compressing 16 lines at a time. You should always use multiples of 16 byte[] inBuffer = new byte[16 * lineBytes]; // Allocate an output buffer. This is where the compressed data will // go. Note that this allocates 1024-byte packets. byte[] outBuffer = new byte[1024]; // Lock down the image image.Access(); // Initialize the compression engine codecs.Options.Jpeg.Save.CmpQualityFactorPredefined = CodecsCmpQualityFactorPredefined.QualityAndSize; codecs.StartCompress( image.Width, image.Height, image.BitsPerPixel, image.Order, image.ViewPerspective, 16 * lineBytes, outBuffer, 0, outBuffer.Length, CodecsCompression.Cmp, MyCodecsCompressDataCallback); // Compress the data int i = 0; while(i < image.Height) // i is incremented at the end { // Compression of the 16-line chunk starts here int j = 0; int inBufferIndex = 0; while((i + j) < image.Height && j < 16) { // Get one line at time image.GetRow(i + j, inBuffer, inBufferIndex, lineBytes); // Move to next line inBufferIndex += lineBytes; j++; } // This is the main function that will do the actual Compression codecs.Compress(inBuffer, 0); i += 16; } // Reset the compression engine codecs.StopCompress(); // Release the image and close the file image.Release(); _compressStream.Close(); // Clean up codecs.Dispose(); } FileStream _compressStream; byte[] _compressBuffer; bool MyCodecsCompressDataCallback(int width, int height, int bitsPerPixel, RasterByteOrder order, RasterViewPerspective viewPerspective, RasterNativeBuffer buffer) { // Write data to the file if(_compressBuffer == null || _compressBuffer.Length < buffer.Length) _compressBuffer = new byte[(int)buffer.Length]; Marshal.Copy(buffer.Data, _compressBuffer, 0, (int)buffer.Length); _compressStream.Write(_compressBuffer, 0, (int)buffer.Length); return true; } static class LEAD_VARS { public const string ImagesDir = @"C:\Users\Public\Documents\LEADTOOLS Images"; } |
SilverlightCSharp | Copy Code |
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SilverlightVB | Copy Code |
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This method initializes the buffered compression engine. The compression is then carried out using the Compress(Byte[],Int32) method. It is ended by the StopCompress method.
If order is set to to RasterByteOrder.Bgr and viewPerspective is RasterViewPerspective.TopLeft then the data that you put into the input buffer must be RasterByteOrder.Bgr and loaded from top left.
The compression process starts after the first call to Compress(Byte[],Int32). The callback is called when the output buffer is filled with compressed data or after completing the compression process. callback is responsible for emptying the output buffer - storing it, sending it, or doing other processing.
The following is a flow chart that shows the relationship of these methods:
Call StopCompress to end the compression process started by a call to StartCompress(Int32,Int32,Int32,RasterByteOrder,RasterViewPerspective,Int32,Byte[],Int32,Int32,CodecsCompression,CodecsCompressDataCallback).
The quality factor of the compressed data is obtained as follows:
This method does not support signed data images.
Target Platforms: Silverlight, Windows XP, Windows Server 2003 family, Windows Server 2008 family, Windows Vista, Windows 7, MAC OS/X (Intel Only)