- 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. bytes required = lines * ((Width + 3) * 2). 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.
- runBufferOffset
- Offset into runBuffer where the copy 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.
- lines
- Number of rows to retrieve.
Visual Basic (Declaration) | |
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<CLSCompliantAttribute(False)> Overloads Public Sub GetRowCompressed( _ ByVal workBuffer() As Byte, _ ByVal runBuffer() As UShort, _ ByVal runBufferOffset As Integer, _ ByVal row As Integer, _ ByVal lines As Integer _ ) |
Visual Basic (Usage) | Copy Code |
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Dim instance As RasterImage Dim workBuffer() As Byte Dim runBuffer() As UShort Dim runBufferOffset As Integer Dim row As Integer Dim lines As Integer instance.GetRowCompressed(workBuffer, runBuffer, runBufferOffset, row, lines) |
C# | |
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[CLSCompliantAttribute(false)] public void GetRowCompressed( byte[] workBuffer, ushort[] runBuffer, int runBufferOffset, int row, int lines ) |
C++/CLI | |
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[CLSCompliantAttribute(false)] public: void GetRowCompressed( array<byte>^ workBuffer, array<ushort>^ runBuffer, int runBufferOffset, int row, int lines ) |
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. bytes required = lines * ((Width + 3) * 2). 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.
- runBufferOffset
- Offset into runBuffer where the copy 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.
- lines
- Number of rows to retrieve.
This example demonstrates the low-level methods for accessing 1-bit compressed image data. It demonstrates the ability to get and put rows, and the ability to process rows in buffer-to-buffer processing. The result of the function is an the first 50 lines are inverted.
Visual Basic | Copy Code |
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Public Sub GetRowCompressedExample() 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(Path.Combine(LEAD_VARS.ImagesDir, "OCR1.TIF"), 1, CodecsLoadByteOrder.Bgr, 1, 1) ' 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 ' Adjust the YOffset if the view perspective is bottom left. Dim nRow As Integer = 500 ' first row to get. Dim nYSize As Integer = 500 ' number of rows to get. If image.ViewPerspective = RasterViewPerspective.BottomLeft Then nRow = image.Height - nRow - nYSize End If ' Allocate the buffers. Dim pBuffer As Byte() = New Byte(Convert.ToInt32((((image.Width + 31) And Not (31)) / 8)) * nYSize - 1) {} ' Buffer to hold the expanded row. Dim pRunBuffer As System.UInt16() = New System.UInt16(((image.Width + 3) * 2) * nYSize - 1) {} ' Buffer to hold the compressed row. If image.IsGlobalMemory Then image.Access() End If ' Get the top nRow lines. image.GetRowCompressed(Nothing, pRunBuffer, 0, nRow, nYSize) ' Expand the compressed data. RasterRleCompressor.ExpandRows(pRunBuffer, pBuffer, 0, image.Width, nYSize) ' Invert the data. Dim n As Integer = 0 Do While n < (image.BytesPerLine * nYSize) pBuffer(n) = pBuffer(n) Xor Convert.ToByte(&HFF) n += 1 Loop ' Compress the inverted data. RasterRleCompressor.CompressRows(pRunBuffer, pBuffer, 0, image.Width, nYSize) ' Put the inverted, compressed data back into the image. image.SetRowCompressed(Nothing, pRunBuffer, 0, nRow, nYSize) If image.IsGlobalMemory Then image.Release() End If codecs.Save(image, Path.Combine(LEAD_VARS.ImagesDir, "IMAGE1_getrowcompresed.BMP"), RasterImageFormat.Bmp, 0) image.Dispose() codecs.Dispose() End Sub 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 GetRowCompressedExample() { RasterCodecs codecs = new RasterCodecs(); // Load the bitmap, at 1 bit per pixel, compressed codecs.Options.Load.Compressed = true; RasterImage image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "OCR1.TIF"), 1, Leadtools.Codecs.CodecsLoadByteOrder.Bgr, 1, 1); // This example does not work with rotated view perspectives. if((image.ViewPerspective != RasterViewPerspective.TopLeft) || (image.ViewPerspective != RasterViewPerspective.BottomLeft)) image.ChangeViewPerspective(RasterViewPerspective.TopLeft); // Adjust the YOffset if the view perspective is bottom left. int nRow = 500; // first row to get. int nYSize = 500; // number of rows to get. if(image.ViewPerspective == RasterViewPerspective.BottomLeft) nRow = image.Height - nRow - nYSize; // Allocate the buffers. byte[] pBuffer = new byte[Convert.ToInt32((((image.Width + 31) & ~(31)) / 8)) * nYSize]; // Buffer to hold the expanded row. ushort[] pRunBuffer = new ushort[((image.Width + 3) * 2) * nYSize]; // Buffer to hold the compressed row. if(image.IsGlobalMemory) image.Access(); // Get the top nRow lines. image.GetRowCompressed(null, pRunBuffer, 0, nRow, nYSize); // Expand the compressed data. RasterRleCompressor.ExpandRows(pRunBuffer, pBuffer, 0, image.Width, nYSize); // Invert the data. for(int n = 0; n < (image.BytesPerLine * nYSize); n++) pBuffer[n] ^= 0xff; // Compress the inverted data. RasterRleCompressor.CompressRows(pRunBuffer, pBuffer, 0, image.Width, nYSize); // Put the inverted, compressed data back into the image. image.SetRowCompressed(null, pRunBuffer, 0, nRow, nYSize); if(image.IsGlobalMemory) image.Release(); codecs.Save(image,Path.Combine(LEAD_VARS.ImagesDir,"IMAGE1_getrowcompresed.BMP"), RasterImageFormat.Bmp, 0); image.Dispose(); codecs.Dispose(); } 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 is available in the (Document/Medical only) Toolkits.
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.
Target Platforms: Silverlight, Windows XP, Windows Server 2003 family, Windows Server 2008 family, Windows Vista, Windows 7, MAC OS/X (Intel Only), Windows Phone 7