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GetRowColumnCompressed(Byte[],UInt16[],Int32,Int32,Int32,Int32) Method
See Also  Example
Leadtools Namespace > RasterImage Class > GetRowColumnCompressed Method : GetRowColumnCompressed(Byte[],UInt16[],Int32,Int32,Int32,Int32) Method



workBuffer
Optional work buffer. Allocating the work buffer speeds processing if you call this method more than once, because if you do not allocate a work buffer, the method allocates and frees a temporary buffer each time it is called. The size of this buffer should be the same as the BytesPerLine property. Pass a null reference (Nothing in Visual Basic) to runBuffer if you do not want to use a work buffer.
runBuffer
The output buffer, which will be filled with 1-bit compressed image data. Calculate the required size of this buffer as follows: bytes required = (Width + 3) * 2.
runBufferOffset
Index into runBuffer where the get operation should start.
row
The number of the row to retrieve. The first row is 0, and the last row is 1 less than the image height.
column
The column offset within the row to retrieve. The first column offset is 0, and the last column offset is 1 less than the image width.
width
The number of pixels to retrieve.
Retrieves a row (or part of a row) of 1-bit compressed data from an image that has been loaded in its compressed format.

Syntax

Visual Basic (Declaration)  
<CLSCompliantAttribute(False)>
Public Overloads Function GetRowColumnCompressed( _
   ByVal workBuffer() As Byte, _
   ByVal runBuffer() As UShort, _
   ByVal runBufferOffset As Integer, _
   ByVal row As Integer, _
   ByVal column As Integer, _
   ByVal width As Integer _
) As Integer
Visual Basic (Usage) Copy Code
Dim instance As RasterImage
Dim workBuffer() As Byte
Dim runBuffer() As UShort
Dim runBufferOffset As Integer
Dim row As Integer
Dim column As Integer
Dim width As Integer
Dim value As Integer
 
value = instance.GetRowColumnCompressed(workBuffer, runBuffer, runBufferOffset, row, column, width)
C#  
[CLSCompliantAttribute(false)]
public int GetRowColumnCompressed( 
   byte[] workBuffer,
   ushort[] runBuffer,
   int runBufferOffset,
   int row,
   int column,
   int width
)
C++/CLI  
[CLSCompliantAttribute(false)]
public:
int GetRowColumnCompressed( 
   array<byte>^ workBuffer,
   array<ushort>^ runBuffer,
   int runBufferOffset,
   int row,
   int column,
   int width
) 

Parameters

workBuffer
Optional work buffer. Allocating the work buffer speeds processing if you call this method more than once, because if you do not allocate a work buffer, the method allocates and frees a temporary buffer each time it is called. The size of this buffer should be the same as the BytesPerLine property. Pass a null reference (Nothing in Visual Basic) to runBuffer if you do not want to use a work buffer.
runBuffer
The output buffer, which will be filled with 1-bit compressed image data. Calculate the required size of this buffer as follows: bytes required = (Width + 3) * 2.
runBufferOffset
Index into runBuffer where the get operation should start.
row
The number of the row to retrieve. The first row is 0, and the last row is 1 less than the image height.
column
The column offset within the row to retrieve. The first column offset is 0, and the last column offset is 1 less than the image width.
width
The number of pixels to retrieve.

Return Value

The number of pixels processed.

Example

This example demonstrates the low-level methods for accessing 1-bit compressed bitmap data. It demonstrates the ability to get and set partial rows, and the ability to process partial rows in buffer-to-buffer processing. The result of the method is an inverted rectangle in the middle of the image.

Visual Basic Copy Code
Public Sub GetRowColumnCompressedExample()
   RasterCodecs.Startup()
   Dim codecs As RasterCodecs = New RasterCodecs()
   ' Load the bitmap, at 1 bit per pixel, compressed
   codecs.Options.Load.Compressed = True
   Dim image As RasterImage = codecs.Load(LeadtoolsExamples.Common.ImagesPath.Path + "OCR1.TIF", 1, CodecsLoadByteOrder.Bgr, 1, 1)

   Dim xOffset As Integer ' Column offset of the rectangle to process.
   Dim xSize As Integer ' Pixel width of the rectangle to process.
   Dim yOffset As Integer ' Row offset of the rectangle to process.
   Dim ySize As Integer ' Pixel height of the rectangle to process.
   Dim i, n As Integer ' Counters.

   Dim buffer As Byte() ' Buffer to hold the expanded row.
   Dim runBuffer As System.UInt16() ' Buffer to hold the compressed row.
   Dim workBuffer As Byte() ' Work buffer.

   ' This example does not work with rotated view perspectives.
   If (image.ViewPerspective <> RasterViewPerspective.TopLeft) OrElse (image.ViewPerspective <> RasterViewPerspective.BottomLeft) Then
      image.ChangeViewPerspective(RasterViewPerspective.TopLeft)
   End If

   ' Specify a rectangle in the middle right part of the displayed image.
   xOffset = image.Width \ 3
   xSize = image.Width - xOffset
   yOffset = image.Height \ 3
   ySize = image.Height \ 3
   ' Adjust the YOffset if the view perspective is bottom left.
   If image.ViewPerspective = RasterViewPerspective.BottomLeft Then
      yOffset = image.Height - yOffset - ySize
   End If

   If image.IsGlobalMemory Then
      image.Access()
   End If
   ' Allocate the buffers.
   buffer = New Byte((xSize + 7) \ 8 - 1) {}
   runBuffer = New System.UInt16((xSize + 3) * 2 - 1) {}
   workBuffer = New Byte(image.BytesPerLine - 1) {}
   ' Invert the colors of pixels in the left half of the rectangle.
   ' Notice that we get the whole rectangle, but process only half of it.
   i = yOffset
   Do While i < (yOffset + ySize)
      image.GetRowColumnCompressed(workBuffer, runBuffer, 0, i, xOffset, xSize)
      RasterRleCompressor.ExpandRow(runBuffer, buffer, 0, 0, xSize)
      n = 0
      Do While n < (xSize / 16)
         buffer(n) = buffer(n) Xor Convert.ToByte(&HFF)
         n += 1
      Loop
      RasterRleCompressor.CompressRow(runBuffer, buffer, 0, 0, xSize)
      image.SetRowColumnCompressed(workBuffer, runBuffer, 0, i, xOffset, xSize)

      i += 1
   Loop
   If image.IsGlobalMemory Then
      image.Release()
   End If

   codecs.Save(image, LeadtoolsExamples.Common.ImagesPath.Path + "IMAGE1_getrowcolcompresed.BMP", RasterImageFormat.Bmp, 0)

   image.Dispose()
   codecs.Dispose()
   RasterCodecs.Shutdown()
End Sub
C# Copy Code
public void GetRowColumnCompressedExample() 

   RasterCodecs.Startup(); 
   RasterCodecs codecs = new RasterCodecs(); 
   // Load the bitmap, at 1 bit per pixel, compressed 
   codecs.Options.Load.Compressed = true; 
   RasterImage image = codecs.Load(LeadtoolsExamples.Common.ImagesPath.Path + "OCR1.TIF", 1, Leadtools.Codecs.CodecsLoadByteOrder.Bgr, 1, 1); 
 
   int xOffset;   // Column offset of the rectangle to process. 
   int xSize;     // Pixel width of the rectangle to process. 
   int yOffset;   // Row offset of the rectangle to process. 
   int ySize;     // Pixel height of the rectangle to process. 
   int i, n;       // Counters. 
 
   byte[] buffer;      // Buffer to hold the expanded row. 
   ushort[] runBuffer; // Buffer to hold the compressed row. 
   byte[] workBuffer;  // Work buffer. 
 
   // This example does not work with rotated view perspectives. 
   if((image.ViewPerspective != RasterViewPerspective.TopLeft) || (image.ViewPerspective != RasterViewPerspective.BottomLeft)) 
      image.ChangeViewPerspective(RasterViewPerspective.TopLeft); 
 
   // Specify a rectangle in the middle right part of the displayed image. 
   xOffset = image.Width / 3; 
   xSize = image.Width - xOffset; 
   yOffset = image.Height / 3; 
   ySize = image.Height / 3; 
   // Adjust the YOffset if the view perspective is bottom left. 
   if(image.ViewPerspective == RasterViewPerspective.BottomLeft) 
   { 
      yOffset = image.Height - yOffset - ySize; 
   } 
 
   if(image.IsGlobalMemory) 
      image.Access(); 
   // Allocate the buffers. 
   buffer = new Byte[(xSize + 7) / 8]; 
   runBuffer = new ushort[(xSize + 3) * 2]; 
   workBuffer = new Byte[image.BytesPerLine]; 
   // Invert the colors of pixels in the left half of the rectangle. 
   // Notice that we get the whole rectangle, but process only half of it. 
   for(i = yOffset; i < (yOffset + ySize); i++) 
   { 
      image.GetRowColumnCompressed(workBuffer, runBuffer, 0, i, xOffset, xSize); 
      RasterRleCompressor.ExpandRow(runBuffer, buffer, 0, 0, xSize); 
      for(n = 0; n < (xSize / 16); n++) 
         buffer[n] ^= 0xFF; 
      RasterRleCompressor.CompressRow(runBuffer, buffer, 0, 0, xSize); 
      image.SetRowColumnCompressed(workBuffer, runBuffer, 0, i, xOffset, xSize); 
 
   } 
   if(image.IsGlobalMemory) 
      image.Release(); 
 
   codecs.Save(image, LeadtoolsExamples.Common.ImagesPath.Path + "IMAGE1_getrowcolcompresed.BMP", RasterImageFormat.Bmp, 0); 
 
   image.Dispose(); 
   codecs.Dispose(); 
   RasterCodecs.Shutdown(); 
}

Remarks

This method is available in the (Document/Medical only).

This method is useful for working with 1-bit images that are loaded in their compressed formats for faster loading and display.

For more information, refer to Speeding Up 1-Bit Documents.

Requirements

Target Platforms: Microsoft .NET Framework 3.0, Windows XP, Windows Server 2003 family, Windows Server 2008 family

See Also