convert VB6 function to VB.NET

  • Thread starter Thread starter Joao Tomas
  • Start date Start date
J

Joao Tomas

Please, can someone help me to translate this single function to VB.NET ?


' DECLARATIONS


Private Const BMP_MAGIC_COOKIE As Short = 19778

Private Structure BITMAPFILEHEADER '14 bytes
Dim bfType As Short
Dim bfSize As Integer
Dim bfReserved1 As Short
Dim bfReserved2 As Short
Dim bfOffBits As Integer
End Structure

Private Structure BITMAPINFOHEADER '40 bytes
Dim biSize As Integer
Dim biWidth As Integer
Dim biHeight As Integer
Dim biPlanes As Short
Dim biBitCount As Short
Dim biCompression As Integer
Dim biSizeImage As Integer
Dim biXPelsPerMeter As Integer
Dim biYPelsPerMeter As Integer
Dim biClrUsed As Integer
Dim biClrImportant As Integer
End Structure


Private Structure RGBQUAD
Dim Red As Byte
Dim Green As Byte
Dim Blue As Byte
Dim Reserved As Byte
End Structure

Private Structure BITMAP
Dim bmType As Integer
Dim bmWidth As Integer
Dim bmHeight As Integer
Dim bmWidthBytes As Integer
Dim bmPlanes As Short
Dim bmBitsPixel As Short
Dim bmBits As Integer
End Structure


Private Const BI_RGB As Integer = 0

Private Declare Function GetProcessHeap Lib "kernel32.dll" () As Integer
'handle

Private Declare Function HeapAlloc Lib "kernel32.dll" (ByVal hHeap As
Integer, ByVal dwFlags As Integer, ByVal dwBytes As Integer) As Integer

Private Declare Function HeapFree Lib "kernel32.dll" (ByVal hHeap As
Integer, ByVal dwFlags As Integer, ByVal lpMem As Integer) As Integer

Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (ByRef
dest As IntPtr, ByVal fromAddress As String, ByVal bytesToCopy As Long)

Private Const HEAP_ZERO_MEMORY As Integer = &H8S

Private m_memBits() As Byte
Private m_memBitmapInfo() As Byte
Private m_bih As BITMAPINFOHEADER
Private m_bfh As BITMAPFILEHEADER


'FUNCTION


Public Function CreateFromPackedDIBPointer(ByRef pDIB As Long) As Boolean

Debug.Assert pDIB <> 0

'Creates a full-color (no palette) DIB from a pointer to a full-color memory
DIB

'get the BitmapInfoHeader

Call CopyMemory(ByVal VarPtr(m_bih.biSize), ByVal pDIB, Len(m_bih))
If m_bih.biBitCount < 16 Then
Debug.Print "Error! DIB was less than 16 colors."
Exit Function 'only supports high-color or full-color dibs
End If

'now get the bitmap bits

If m_bih.biSizeImage < 1 Then Exit Function 'return False
ReDim m_memBits(0 To m_bih.biSizeImage - 1)
Call CopyMemory(m_memBits(0), ByVal pDIB + 40, m_bih.biSizeImage)

'and BitmapInfo variable-length UDT

ReDim m_memBitmapInfo(0 To 39) 'don't need first 14 bytes (fileinfo)
Call CopyMemory(m_memBitmapInfo(0), m_bih, Len(m_bih))

'create a file header
With m_bfh
.bfType = BMP_MAGIC_COOKIE
.bfSize = 55 + m_bih.biSizeImage 'size of file as written to disk
.bfReserved1 = 0&
.bfReserved2 = 0&
.bfOffBits = 54 'BitmapInfoHeader + BitmapFileHeader
End With

'and return True
CreateFromPackedDIBPointer = True

End Function
 
Define the struct with 'Sequential' Layout.

Functions would be simple DllImport's.

What's the problem that you are facing?
 
You may want to use 'memcpy' defined in 'user32.dll' (or 'kernel32.dll'...
just slipping from my mind)..
 
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