Public Overloads Function SetRowColumn( _
ByVal row As Integer, _
ByVal column As Integer, _
ByVal buffer As IntPtr, _
ByVal bufferCount As Integer _
) As Integer
The number of the row to update. The first row is 0, and the last row is 1 less than the image height.
The column offset within the row to update. The first column offset is 0, and the last column offset is 1 less than the image width.
Pointer to an unmanaged memory buffer containing the image data. The buffer should contain uncompressed data regardless of whether the image is compressed or not.
The number of bytes to update. Consider the bits per pixel, and avoid specifying a number that goes past the end of the row.
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 a 48-bit image, every six bytes represents one pixel. For a 64-bit image, every eight bytes represents one pixel.
The number of bytes put.
By using this low-level method to update any part of a row, you can write a procedure that updates a single pixel or a rectangular area within the image.
This method accepts an offset parameter ( column) in pixels and a length ( bufferCount) in bytes. Therefore, you must consider the bits per pixel of the image when specifying these parameters. The following table describes the rules:
|Bits Per Pixel||Column Offset (in Pixels)||Bytes to Get|
|1||Must be a multiple of 8 (such as 0, 8, or 16).||Can be any number up to the end of the row. Consider that there are 8 pixels per byte.|
|4||Must be an even number (such as 0, 2, or 4).||Can be any number up to the end of the row. Consider that there are 2 pixels per byte.|
|8||Can be any column within the image.||Can be any number up to the end of the row. Consider that there is 1 pixel per byte.|
|16||Can be any column within the image.||Must be a multiple of 2 (such as 2, 4, or 6), because there are 2 bytes per pixel.|
|24||Can be any column within the image.||Must be a multiple of 3 (such as 3, 6, or 9), because there are 3 bytes per pixel.|
|32||Can be any column within the image.||Must be a multiple of 4 (such as 4, 8, or 12), because there are 4 bytes per pixel.|
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: To calculate the correct size for a single row of image data:
(((Width * BitsPerPixel) + 31) >> 3)) & ~3
(((Width * BitsPerPixel) + 7) / 8)
For more information, refer to Introduction to Image Processing With LEADTOOLS.
For an example, refer to GetRowColumn.
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