[RESOLVED] how to make a full screen screenshot

[theonlyhugeg]

hi everybody
im working on this little application for myself... when its done i want it to take screen shots of the entire screen at a given time. like every hour for example.
right now im still stuck on the fist part. how to you take a full screen screen shot? anyone know? i know the crtl + PrtSc option, but i want to make an application which can do it by itself.
so far i only found
public sub command1_Click()
Me.PrintForm
End Sub
but thats no use as it only takes a picture of the application. i need the whole screen.
please help. have been trying to figure out for days...
thanks in advance!!

[LaVolpe]

please help. have been trying to figure out for days...
thanks in advance!!

For days? A simple search would have had you up & running in 5 minutes. Just searching this forum for Screen Capture has 12 pages of postings.

[Lord Orwell]

the simple way is using the keybd_event api call. You tell it to raise a "prt scr" keypress and it will take a snapshot of the whole screen. Ctrl-prtscr if i remember correctly doesn't take the whole screen. It takes the active window.

Note that you HAVE to use the api keybd_event for this. Sendkeys, etc. will NOT work.

[theonlyhugeg]

For days? A simple search would have had you up & running in 5 minutes. Just searching this forum for Screen Capture has 12 pages of postings.

hi
i have indeed found something very useful.
currently im using this:


Option Explicit

Private Declare Sub keybd_event Lib "user32" (ByVal bVk As Byte, ByVal _
bScan As Byte, ByVal dwFlags As Long, ByVal dwExtraInfo As Long)

Private Declare Function GetVersionExA Lib "kernel32" _
(lpVersionInformation As OSVERSIONINFO) As Integer

Private Type OSVERSIONINFO
dwOSVersionInfoSize As Long
dwMajorVersion As Long
dwMinorVersion As Long
dwBuildNumber As Long
dwPlatformId As Long
szCSDVersion As String * 128
End Type

Private Const KEYEVENTF_KEYUP = &H2
Private Const VK_SNAPSHOT = &H2C
Private Const VK_MENU = &H12

Dim blnAboveVer4 As Boolean

Private Sub Command1_Click()
If blnAboveVer4 Then
keybd_event VK_SNAPSHOT, 0, 0, 0
Else
keybd_event VK_SNAPSHOT, 1, 0, 0
End If
End Sub

Private Sub Command2_Click()
If blnAboveVer4 Then
keybd_event VK_SNAPSHOT, 1, 0, 0
Else
keybd_event VK_MENU, 0, 0, 0
keybd_event VK_SNAPSHOT, 0, 0, 0
keybd_event VK_SNAPSHOT, 0, KEYEVENTF_KEYUP, 0
keybd_event VK_MENU, 0, KEYEVENTF_KEYUP, 0
End If
End Sub

Private Sub Command3_Click()
' Load the captured image into a PictureBox and print it
Picture1.Picture = Clipboard.GetData()


End Sub

Private Sub Form_Load()
Dim osinfo As OSVERSIONINFO
Dim retvalue As Integer

osinfo.dwOSVersionInfoSize = 148
osinfo.szCSDVersion = Space$(128)
retvalue = GetVersionExA(osinfo)
If osinfo.dwMajorVersion > 4 Then blnAboveVer4 = True

Picture1.Visible = True
Command1.Caption = "Print Screen"
Command2.Caption = "Alt+Print Screen"
Command3.Caption = "Print Image"
End Sub


the print image command doesnt actually print the image, it only puts it in the picture box, and thats exactly what i want. but it doesnt show the entire screen as it wont fit. i know it is very simple to resize the screenshot into the picture box, and i knew how to do this before but i just cant remember and cant seem to find the right one which works for this method. also is there a way to safe the resized picture by itself in a predefined location without the user having to do this?
if anyone knows please help
thanks

[LaVolpe]

hmmm... Since you showed initiative, let me show you a fairly simple alternative.

1. Add a picturebox to your form, set properties > AutoRedraw=True, Visible=False, Appearance=Flat, BorderStyle=0
2. Add this code to a timer event, click event, or to a private function/sub.

' these Declarations go in the declaration section
Private Declare Function BitBlt Lib "gdi32.dll" (ByVal hDestDC As Long, ByVal x As Long, ByVal y As Long, ByVal nWidth As Long, ByVal nHeight As Long, ByVal hSrcDC As Long, ByVal xSrc As Long, ByVal ySrc As Long, ByVal dwRop As Long) As Long
Private Declare Function ReleaseDC Lib "user32.dll" (ByVal hwnd As Long, ByVal hdc As Long) As Long
Private Declare Function GetWindowDC Lib "user32.dll" (ByVal hwnd As Long) As Long
Private Declare Function GetDesktopWindow Lib "user32.dll" () As Long
Private Const CAPTUREBLT As Long = &H40000000

Private Sub Command1_Click()
    Dim dtopDC As Long, dtopHwnd As Long
    
    ' clear the picture box & resize it if needed
    Picture1.Cls
    ' adjust next line if form's scalemode is not vbTwips so picbox is screen width/height
    Picture1.Move Picture1.Left, Picture1.Top, Screen.Width, Screen.Height
    
    ' get the desktop window handle and its DC
    dtopHwnd = GetDesktopWindow
    dtopDC = GetWindowDC(dtopHwnd)
    ' paint the desktop into the hidden picturebox & release desktop DC
    BitBlt Picture1.hdc, 0, 0, Screen.Width \ Screen.TwipsPerPixelX, Screen.Height \ Screen.TwipsPerPixelY, dtopDC, 0, 0, vbSrcCopy Or CAPTUREBLT
    ReleaseDC dtopHwnd, dtopDC
    
    ' save the picture
    SavePicture Picture1.Image, "C:\screenshot.bmp"

End Sub

Edit: regarding seeing the entire screen shot. You can see above, one way to size the picbox to the screen dimensions. But you still won't get the entire image in view because form borders & titlebar will take away from the amount of space for your picbox. Of course, you could copy the screenshot into a hidden picbox (as shown above) then scale the image, say 25% or so, to a visible picbox. The hidden picbox would be used for saving fullscreen or you can save the 25% scaled version, or both.

[theonlyhugeg]

thanks for that code!
i can finally start with the real application now.