GetRow(int,IntPtr,int) Method

Summary

Retrieves one or more rows of image data from this RasterImage into un unmanaged memory buffer.

Syntax

C++

Java

public int GetRow( 
   int row, 
   IntPtr buffer, 
   int bufferCount 
)

Public Overloads Function GetRow( _ 
   ByVal row As Integer, _ 
   ByVal buffer As IntPtr, _ 
   ByVal bufferCount As Integer _ 
) As Integer

public long getRow( 
  int row,  
  byte[] buffer,  
  long bufferCount 
)

public: 
int GetRow(  
   int row, 
   IntPtr buffer, 
   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
Pointer to an unmanaged memory buffer to hold the image data that this method gets. The size of this buffer must be large enough to hold the image data.

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 * (Image.Width * Image.Height + 7) / 8;

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.Romm. RasterByteOrder.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.