LEADTOOLS (Leadtools assembly)
LEAD Technologies, Inc

GetRow(Int32,IBuffer,Int32,Int32) Method

Example 





Leadtools Namespace > RasterImage Class > GetRow Method : GetRow(Int32,IBuffer,Int32,Int32) Method
The number of the row to retrieve. The first row is 0, and the last row is 1 less than the image height.
Buffer to hold the image data that this method gets. The size of this buffer must be large enough to hold the image data.
The zero-based index into the buffer where the get operation should start.

The number of bytes in the row to retrieve. To get a full row, use the value in the BytesPerLine property

When getting less than full row, you must consider the bits per pixel. For a 1-bit image, each byte represents 8 pixels. For a 4-bit image, each byte represents 2 pixels. For an 8-bit image, each byte represents 1 pixel. For a 16-bit image, every 2 bytes represents one pixel. For 24-bit images, every three bytes represents one pixel. For a 32-bit image, every four bytes represents one pixel. For 48-bit images, every six bytes represents one pixel. For 64-bit images, every eight bytes represents one pixel.

You can use the BitsPerPixel property with integer math to calculate the number of bytes needed for a particular number of pixels. For example:

            NumberOfBytes = (Image.BitsPerPixel * NumberOfPixels) / 8;
            if((Image.BitsPerPixel * NumberOfPixels) % 8)
               NumberOfBytes = NumberOfBytes + 1; // Round up if necessary for a 1- or 4-bit image

Retrieves one or more rows of image data from this RasterImage into a managed memory buffer. .NET support WinRT support
Syntax
public int GetRow( 
   int row,
   IBuffer buffer,
   int bufferIndex,
   int bufferCount
)
'Declaration
 
Public Overloads Function GetRow( _
   ByVal row As Integer, _
   ByVal buffer As IBuffer, _
   ByVal bufferIndex As Integer, _
   ByVal bufferCount As Integer _
) As Integer
'Usage
 
Dim instance As RasterImage
Dim row As Integer
Dim buffer As IBuffer
Dim bufferIndex As Integer
Dim bufferCount As Integer
Dim value As Integer
 
value = instance.GetRow(row, buffer, bufferIndex, bufferCount)
public int GetRow( 
   int row,
   IBuffer buffer,
   int bufferIndex,
   int bufferCount
)
 function Leadtools.RasterImage.GetRow(Int32,IBuffer,Int32,Int32)( 
   row ,
   buffer ,
   bufferIndex ,
   bufferCount 
)

public:
int GetRow( 
   int row,
   IBuffer^ buffer,
   int bufferIndex,
   int bufferCount
)

Parameters

row
The number of the row to retrieve. The first row is 0, and the last row is 1 less than the image height.
buffer
Buffer to hold the image data that this method gets. The size of this buffer must be large enough to hold the image data.
bufferIndex
The zero-based index into the buffer where the get operation should start.
bufferCount

The number of bytes in the row to retrieve. To get a full row, use the value in the BytesPerLine property

When getting less than full row, you must consider the bits per pixel. For a 1-bit image, each byte represents 8 pixels. For a 4-bit image, each byte represents 2 pixels. For an 8-bit image, each byte represents 1 pixel. For a 16-bit image, every 2 bytes represents one pixel. For 24-bit images, every three bytes represents one pixel. For a 32-bit image, every four bytes represents one pixel. For 48-bit images, every six bytes represents one pixel. For 64-bit images, every eight bytes represents one pixel.

You can use the BitsPerPixel property with integer math to calculate the number of bytes needed for a particular number of pixels. For example:

            NumberOfBytes = (Image.BitsPerPixel * NumberOfPixels) / 8;
            if((Image.BitsPerPixel * NumberOfPixels) % 8)
               NumberOfBytes = NumberOfBytes + 1; // Round up if necessary for a 1- or 4-bit image

Return Value

The number of bytes copied.
Remarks

This method copies image data from the RasterImage object to a buffer that you specify. The data is copied exactly as it is stored in the image. The image memory must be locked when you use this method. Normally, you can call Access to lock the memory before starting an operation that uses this method. Then call Release when the operation is finished.

Note: The data in the buffer will be padded to BytesPerLine.

Use the BytesPerLine property of the RasterImage object to determine the byte count of each line. Color order is determined by the Order property. This value can be RasterByteOrder.Rgb, RasterByteOrder.Bgr, RasterByteOrder.Gray or RasterByteOrder.RommRasterByteOrder.Gray is only valid for 12 and 16-bit grayscale images. Support for 12 and 16-bit grayscale images is only available in the Document/Medical Imaging editions.

Example
  
Public Sub GetRowTest()
      Dim codecs As RasterCodecs = New RasterCodecs()
      Dim image As RasterImage = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "IMAGE1.CMP"))

      Dim row1 As Byte() = New Byte(image.BytesPerLine - 1) {}
      Dim row2 As Byte() = New Byte(image.BytesPerLine - 1) {}

      If image.IsGlobalMemory Then
         image.Access()
      End If
      Dim y As Integer = 0
      Do While y < image.Height \ 2
         image.GetRow(y, row1, 0, row1.Length)
         image.GetRow(image.Height - y - 1, row2, 0, row2.Length)

         image.SetRow(y, row2, 0, row2.Length)
         image.SetRow(image.Height - y - 1, row1, 0, row1.Length)
         y += 1
      Loop
      If image.IsGlobalMemory Then
         image.Release()
      End If

      codecs.Save(image, Path.Combine(LEAD_VARS.ImagesDir, "IMAGE1_getrow.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
public void GetRowTest()
   {
      RasterCodecs codecs = new RasterCodecs();
      RasterImage image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "IMAGE1.CMP"));

      byte[] row1 = new byte[image.BytesPerLine];
      byte[] row2 = new byte[image.BytesPerLine];

      if(image.IsGlobalMemory)
         image.Access();
      for(int y = 0; y < image.Height / 2; y++)
      {
         image.GetRow(y, row1, 0, row1.Length);
         image.GetRow(image.Height - y - 1, row2, 0, row2.Length);

         image.SetRow(y, row2, 0, row2.Length);
         image.SetRow(image.Height - y - 1, row1, 0, row1.Length);
      }
      if(image.IsGlobalMemory)
         image.Release();

      codecs.Save(image, Path.Combine(LEAD_VARS.ImagesDir, "IMAGE1_getrow.BMP"), RasterImageFormat.Bmp, 0);

      image.Dispose();
      codecs.Dispose();
   }

static class LEAD_VARS
{
   public const string ImagesDir = @"C:\Users\Public\Documents\LEADTOOLS Images";
}
RasterImageExamples.prototype.GetRowTest = function ( )
{
   Tools.SetLicense ( ) ;

   with (Leadtools) {
      with (Leadtools.Codecs) {
         var codecs = new RasterCodecs();

         var srcFileName = "Assets\\Image1.cmp";
         var image;
         return Tools.AppInstallFolder().getFileAsync(srcFileName).then(function (loadFile) {
            return codecs.loadAsync(LeadStreamFactory.create(loadFile))
         })
            .then(function (img) {
               image = img;

               var row1 = new Array(image.BytesPerLine);
               var row2 = new Array(image.BytesPerLine);

               if (image.isGlobalMemory)
                  image.accessData();
               for (var y = 0; y < image.height / 2; y++) {
                  image.getRow(y, row1, 0, row1.length);
                  image.getRow(image.height - y - 1, row2, 0, row2.length);

                  image.setRow(y, row2, 0, row2.length);
                  image.setRow(image.height - y - 1, row1, 0, row1.length);
               }
               if (image.isGlobalMemory)
                  image.releaseData();

               return Tools.AppLocalFolder().createFileAsync("IMAGE1_getrow.BMP")
            })
            .then(function (saveFile) {
               var saveStream = LeadStreamFactory.create(saveFile);
               return codecs.saveAsync(image, saveStream, RasterImageFormat.bmp, 24)
            })
            .then(function () {

               image.close();
               codecs.close();
            });
      }
   }
}
[TestMethod]
public async Task GetRowTest()
{
   RasterCodecs codecs = new RasterCodecs();
   string srcFileName = @"Assets\Image1.cmp";
   StorageFile loadFile = await Tools.AppInstallFolder.GetFileAsync(srcFileName);
   RasterImage image = await codecs.LoadAsync(LeadStreamFactory.Create(loadFile));

   byte[] row1 = new byte[image.BytesPerLine];
   byte[] row2 = new byte[image.BytesPerLine];

   if (image.IsGlobalMemory)
      image.AccessData();
   for (int y = 0; y < image.Height / 2; y++)
   {
      image.GetRow(y, row1, 0, row1.Length);
      image.GetRow(image.Height - y - 1, row2, 0, row2.Length);

      image.SetRow(y, row2, 0, row2.Length);
      image.SetRow(image.Height - y - 1, row1, 0, row1.Length);
   }
   if (image.IsGlobalMemory)
      image.ReleaseData();

   StorageFile saveFile = await Tools.AppLocalFolder.CreateFileAsync("IMAGE1_getrow.BMP");
   ILeadStream saveStream = LeadStreamFactory.Create(saveFile);
   await codecs.SaveAsync(image, saveStream, RasterImageFormat.Bmp, 24);

   image.Dispose();
   codecs.Dispose();
}
public void GetRowTest(RasterImage image, Stream destStream)
{
   byte[] row1 = new byte[image.BytesPerLine];
   byte[] row2 = new byte[image.BytesPerLine];
   if (image.IsGlobalMemory)
      image.Access();
   for (int y = 0; y < image.Height / 2; y++)
   {
      image.GetRow(y, row1, 0, row1.Length);
      image.GetRow(image.Height - y - 1, row2, 0, row2.Length);

      image.SetRow(y, row2, 0, row2.Length);
      image.SetRow(image.Height - y - 1, row1, 0, row1.Length);
   }
   if (image.IsGlobalMemory)
      image.Release();

   RasterCodecs codecs = new RasterCodecs();
   codecs.Save(image, destStream, RasterImageFormat.Bmp, 0);

   image.Dispose();
}
Public Sub GetRowTest(ByVal image As RasterImage, ByVal destStream As Stream)
   Dim row1 As Byte() = New Byte(image.BytesPerLine - 1){}
   Dim row2 As Byte() = New Byte(image.BytesPerLine - 1){}
   If image.IsGlobalMemory Then
      image.Access()
   End If
   Dim y As Integer = 0
   Do While y < image.Height / 2
      image.GetRow(y, row1, 0, row1.Length)
      image.GetRow(image.Height - y - 1, row2, 0, row2.Length)

      image.SetRow(y, row2, 0, row2.Length)
      image.SetRow(image.Height - y - 1, row1, 0, row1.Length)
      y += 1
   Loop
   If image.IsGlobalMemory Then
      image.Release()
   End If

   Dim codecs As RasterCodecs = New RasterCodecs()
   codecs.Save(image, destStream, RasterImageFormat.Bmp, 0)

   image.Dispose()
End Sub
Requirements

Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

See Also

Reference

RasterImage Class
RasterImage Members
Overload List

 

 

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