BitmapData type

The description of the pixels that Bitmap.LockBits has locked in memory: their size, layout and address.

The type mirrors the GDI+ BitmapData structure. A program declares a variable of the type, passes it to LockBits, and reads the pixels from the address in Scan0. UnlockBits takes it back.

Fields

Field Type Meaning
Width Long The width of the locked area in pixels.
Height Long The height of the locked area in pixels.
Stride Long The number of bytes from the start of one row to the start of the next. It is a multiple of 4, and negative when the rows run from the bottom up.
PixelFormat PixelFormat The pixel format of the locked data.
Scan0 LongPtr The address of the first pixel. The pixel (x, y) of a format with b bytes per pixel is at Scan0 + y * Stride + x * b.
Reserved LongPtr Reserved by GDI+. A program leaves it alone. 
Dim user As GdiPlusUser = GdiPlusUser()

Dim bmp As Bitmap = Bitmap(4!, 4!)
bmp.Pixel(2, 1) = Color(255, 1, 2, 3)

Dim bd As BitmapData
bmp.LockBits GpRect(0, 0, 4, 4), ImageLockModeRead, PixelFormat32bppARGB, bd
Dim v As Long
GetMem4 bd.Scan0 + 1 * bd.Stride + 2 * 4, v       ' the pixel (2, 1)
bmp.UnlockBits bd
Debug.Print bd.Width & " " & bd.Height & " " & bd.Stride
Debug.Print Hex$(v)
' Output:
' 4 4 16
' FF010203

See Also