Public Class ScreenCapture
' The ScreenCapture class allows you to take screenshots (printscreens)
' of the desktop or of individual windows.
'
' Usage:
'
' PictureBox1.Image = ScreenCapture.GrabScreen()
' PictureBox1.Image = ScreenCapture.GrabActiveWindow()
' PictureBox1.Image = ScreenCapture.GrabWindow(SomeHwnd)
'
' PictureBox1.Image = ScreenCapture.GrabScreen(X, Y, Width, Height)
' PictureBox1.Image = ScreenCapture.GrabScreen(Rect)
' PictureBox1.Image = ScreenCapture.GrabScreen(Location, Size)
#Region "Constants"
Private Const HORZRES As Integer = 8
Private Const VERTRES As Integer = 10
Private Const SRCCOPY = &HCC0020
Private Const SRCINVERT = &H660046
Private Const USE_SCREEN_WIDTH = -1
Private Const USE_SCREEN_HEIGHT = -1
#End Region
#Region "API's"
Private Structure RECT
Public Left As Int32
Public Top As Int32
Public Right As Int32
Public Bottom As Int32
End Structure
Private Declare Function CreateDC Lib "gdi32" Alias "CreateDCA" (ByVal lpDriverName As String, ByVal lpDeviceName As String, ByVal lpOutput As String, ByVal lpInitData As String) As Integer
Private Declare Function CreateCompatibleDC Lib "GDI32" (ByVal hDC As Integer) As Integer
Private Declare Function DeleteDC Lib "GDI32" (ByVal hDC As Integer) As Integer
Private Declare Function GetWindowDC Lib "user32" Alias "GetWindowDC" (ByVal hwnd As Long) As Integer
Private Declare Function ReleaseDC Lib "user32" Alias "ReleaseDC" (ByVal hwnd As Long, ByVal hdc As Long) As Long
Private Declare Function GetDeviceCaps Lib "gdi32" Alias "GetDeviceCaps" (ByVal hdc As Integer, ByVal nIndex As Integer) As Integer
Private Declare Function CreateCompatibleBitmap Lib "GDI32" (ByVal hDC As Integer, ByVal nWidth As Integer, ByVal nHeight As Integer) As Integer
Private Declare Function SelectObject Lib "GDI32" (ByVal hDC As Integer, ByVal hObject As Integer) As Integer
Private Declare Function DeleteObject Lib "GDI32" (ByVal hObj As Integer) As Integer
Private Declare Function BitBlt Lib "GDI32" (ByVal hDestDC As Integer, ByVal X As Integer, ByVal Y As Integer, ByVal nWidth As Integer, ByVal nHeight As Integer, ByVal hSrcDC As Integer, ByVal SrcX As Integer, ByVal SrcY As Integer, ByVal Rop As Integer) As Integer
Private Declare Function GetForegroundWindow Lib "user32" Alias "GetForegroundWindow" () As Integer
Private Declare Function IsWindow Lib "user32" Alias "IsWindow" (ByVal hwnd As Integer) As Long
Private Declare Function GetWindowRect Lib "user32.dll" (ByVal hWnd As Integer, ByRef lpRect As RECT) As Int32
#End Region
#Region "Public Methods."
Public Shared Function GrabScreen() As Bitmap
Return GrabScreen(0, 0, USE_SCREEN_WIDTH, USE_SCREEN_HEIGHT)
End Function
Public Shared Function GrabScreen(ByVal Rect As Rectangle) As Bitmap
Return GrabScreen(Rect.X, Rect.Y, Rect.Width, Rect.Height)
End Function
Public Shared Function GrabScreen(ByVal Location As System.Drawing.Point, ByVal Size As System.Drawing.Size) As Bitmap
Return GrabScreen(Location.X, Location.Y, Size.Width, Size.Height)
End Function
Public Shared Function GrabScreen(ByVal X As Integer, ByVal Y As Integer, ByVal Width As Integer, ByVal Height As Integer) As Bitmap
Dim hDesktopDC As Integer
Dim hOffscreenDC As Integer
Dim hBitmap As Integer
Dim hOldBmp As Integer
Dim MyBitmap As Bitmap
' Get the desktop device context.
hDesktopDC = CreateDC("DISPLAY", "", "", "")
If hDesktopDC Then
' Adjust width and height.
If Width = USE_SCREEN_WIDTH Then
Width = GetDeviceCaps(hDesktopDC, HORZRES)
End If
If Height = USE_SCREEN_HEIGHT Then
Height = GetDeviceCaps(hDesktopDC, VERTRES)
End If
' Create an offscreen device context.
hOffscreenDC = CreateCompatibleDC(hDesktopDC)
If hOffscreenDC Then
' Create a bitmap for our offscreen device context.
hBitmap = CreateCompatibleBitmap(hDesktopDC, Width, Height)
If hBitmap Then
' Copy the image and create an instance of the Bitmap class.
hOldBmp = SelectObject(hOffscreenDC, hBitmap)
BitBlt(hOffscreenDC, 0, 0, Width, Height, hDesktopDC, X, Y, SRCCOPY)
MyBitmap = Bitmap.FromHbitmap(New IntPtr(hBitmap))
' Clean up.
DeleteObject(SelectObject(hOffscreenDC, hOldBmp))
End If
DeleteDC(hOffscreenDC)
End If
DeleteDC(hDesktopDC)
End If
' Return our Bitmap instance.
Return MyBitmap
End Function
Public Shared Function GrabActiveWindow() As Bitmap
Return GrabWindow(GetForegroundWindow())
End Function
Public Shared Function GrabWindow(ByVal hWnd As Int32) As Bitmap
Dim hWindowDC As Long
Dim hOffscreenDC As Long
Dim rec As RECT
Dim nWidth As Long
Dim nHeight As Long
Dim hBitmap As Long
Dim hOldBmp As Long
Dim MyBitmap As Bitmap
' Verify if a valid window handle was provided.
If hWnd <> 0 And IsWindow(hWnd) Then
' Get the window's device context.
hWindowDC = GetWindowDC(hWnd)
If hWindowDC Then
' Get width and height.
If GetWindowRect(hWnd, rec) Then
nWidth = rec.Right - rec.Left
nHeight = rec.Bottom - rec.Top
' Create an offscreen device context.
hOffscreenDC = CreateCompatibleDC(hWindowDC)
If hOffscreenDC Then
' Create a bitmap for our offscreen device context.
hBitmap = CreateCompatibleBitmap(hWindowDC, nWidth, nHeight)
If hBitmap Then
' Copy the image and create an instance of the Bitmap class.
hOldBmp = SelectObject(hOffscreenDC, hBitmap)
BitBlt(hOffscreenDC, 0, 0, nWidth, nHeight, hWindowDC, 0, 0, SRCCOPY)
MyBitmap = Bitmap.FromHbitmap(New IntPtr(hBitmap))
' Clean up.
DeleteObject(SelectObject(hOffscreenDC, hOldBmp))
End If
DeleteDC(hOffscreenDC)
End If
End If
ReleaseDC(hWnd, hWindowDC)
End If
End If
' Return our Bitmap instance.
Return MyBitmap
End Function
#End Region
End Class
