Can GDI get the mouse on a screen capture?
gregory_may
doesnt grab the Mouse Pointer, Cursor, or Tool Tips. Does anyone have a
suggestion on how to add these elements into my screen capture?
I have tested this code and it seems to perform at least 15 frames/second++
just
fine (I just need the mouse, cursor & tool tips). But, If there is a better
way, I am open!
Thanks!!!
------------
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 CreateCompatibleBitmap Lib "GDI32" (ByVal hDC As
Integer, ByVal nWidth As Integer, ByVal nHeight As Integer) As Integer
Private Declare Function GetDeviceCaps Lib "gdi32" Alias "GetDeviceCaps"
(ByVal hdc As Integer, ByVal nIndex As Integer) As Integer
Private Declare Function SelectObject Lib "GDI32" (ByVal hDC As Integer,
ByVal hObject As Integer) As Integer
Private Declare Function BitBlt Lib "GDI32" (ByVal srchDC As Integer, ByVal
srcX As Integer, ByVal srcY As Integer, ByVal srcW As Integer, ByVal srcH As
Integer, ByVal desthDC As Integer, ByVal destX As Integer, ByVal destY As
Integer, ByVal op As Integer) As Integer
Private Declare Function DeleteDC Lib "GDI32" (ByVal hDC As Integer) As
Integer
Private Declare Function DeleteObject Lib "GDI32" (ByVal hObj As Integer) As
Integer
Const SRCCOPY As Integer = &HCC0020
Private oBackground As System.Drawing.Bitmap
Private FW, FH As Integer
Public Sub CaptureScreen()
Dim hSDC, hMDC As Integer
Dim hBMP, hBMPOld As Integer
Dim r As Integer
Try
hSDC = CreateDC("DISPLAY", "", "", "")
hMDC = CreateCompatibleDC(hSDC)
FW = GetDeviceCaps(hSDC, 8)
FH = GetDeviceCaps(hSDC, 10)
hBMP = CreateCompatibleBitmap(hSDC, FW, FH)
hBMPOld = SelectObject(hMDC, hBMP)
r = BitBlt(hMDC, 0, 0, FW, FH, hSDC, 0, 0, 13369376)
hBMP = SelectObject(hMDC, hBMPOld)
r = DeleteDC(hSDC)
r = DeleteDC(hMDC)
oBackground = System.Drawing.Image.FromHbitmap(New IntPtr(hBMP))
DeleteObject(hBMP)
DeleteObject(hBMPOld)
'Seems to be a memory hole in fromHbitmap ....
GC.Collect()
Catch ex As Exception
Debug.WriteLine("General GDI+ Error")
End Try
End Sub
Mike D Sutton
> doesnt grab the Mouse Pointer, Cursor, or Tool Tips. Does anyone have a
> suggestion on how to add these elements into my screen capture?
>
> I have tested this code and it seems to perform at least 15 frames/second++
> just
> fine (I just need the mouse, cursor & tool tips). But, If there is a better
> way, I am open!
Try this:
'***
Dim CurInf As CursorInfo
Dim CurPos As PointAPI
hSDC = CreateDC("DISPLAY", "", "", "")
hMDC = CreateCompatibleDC(hSDC)
FW = GetDeviceCaps(hSDC, HORIZRES)
FH = GetDeviceCaps(hSDC, VERTRES)
hBMP = CreateCompatibleBitmap(hSDC, FW, FH)
Call DeleteDC(hSDC)
hBMPOld = SelectObject(hMDC, hBMP)
Call BitBlt(hMDC, 0, 0, FW, FH, hSDC, 0, 0, SRCCOPY)
CurInf.cbSize = Len(CurInf)
Call GetCursorInfo(CurInf)
If (CurInf.flags And CURSOR_SHOWING) Then
Call GetCursorPos(CurPos)
Call DrawIconEx(hMDC, CurPos.X, CurPos.Y, _
CurInf.hCursor, 0, 0, 0, False, DI_NORMAL)
End If
Call SelectObject(hMDC, hBMPOld)
Call DeleteDC(hMDC)
oBackground = System.Drawing.Image.FromHbitmap(New IntPtr(hBMP))
' This shouldn't be deleted until after oBackground goes out of scope
' It may also be the cause of your prior leak (Fixed a couple of GDI bugs too though)
' Call DeleteObject(hBMP)
'***
And the VB6 declares, you'll need to do any conversion of them to VB.NET i.e. find an replace "Long" for "Integer" etc:
'***
Private Declare Function GetCursorInfo Lib "User32.dll" (ByRef pCI As CursorInfo) As Long
Private Declare Function GetCursorPos Lib "User32.dll" (lpPoint As PointAPI) As Long
Private Declare Function DrawIconEx Lib "User32.dll" (ByVal hDC As Long, _
ByVal xLeft As Long, ByVal yTop As Long, ByVal hIcon As Long, _
ByVal cxWidth As Long, ByVal cyWidth As Long, ByVal istepIfAniCur As Long, _
ByVal hbrFlickerFreeDraw As Long, ByVal diFlags As Long) As Long
Private Type PointAPI
X As Long
Y As Long
End Type
Private Type CursorInfo
cbSize As Long
flags As Long
hCursor As Long
ptScreenPos As PointAPI
End Type
Private Const CURSOR_SHOWING As Long = &H1
Private Const DI_NORMAL As Long = &H3
'***
Hope this helps,
Mike
- Microsoft Visual Basic MVP -
E-Mail: ED...@mvps.org
WWW: Http://www.mvps.org/EDais/
gregory_may
g.
"Mike D Sutton" <ED...@mvps.org> wrote in message
news:Odq7RE03...@TK2MSFTNGP10.phx.gbl...
gregory_may
definition. I also moved the DeleteDC call you added until after the BitBlt
call.
There seems to be 2 problems with this code:
1) Nothing is happening in Call GetCursorInfo(CurInf).
2) if I Omit the gc.collect, things slow down and there is a leak some place
(I am OK having GC.Collect here, its just WEIRD the code needs the
GC.Collect call to work at a reasonable speed).
Any thoughts on how to fix the GetCursorInfo(CurInf) call?
Thanks again!
g.
Public Class ScreenCapture
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 CreateCompatibleBitmap Lib "GDI32" (ByVal hDC As
Integer, ByVal nWidth As Integer, ByVal nHeight As Integer) As Integer
Private Declare Function GetDeviceCaps Lib "gdi32" Alias "GetDeviceCaps"
(ByVal hdc As Integer, ByVal nIndex As Integer) As Integer
Private Declare Function SelectObject Lib "GDI32" (ByVal hDC As Integer,
ByVal hObject As Integer) As Integer
Private Declare Function BitBlt Lib "GDI32" (ByVal srchDC As Integer, ByVal
srcX As Integer, ByVal srcY As Integer, ByVal srcW As Integer, ByVal srcH As
Integer, ByVal desthDC As Integer, ByVal destX As Integer, ByVal destY As
Integer, ByVal op As Integer) As Integer
Private Declare Function DeleteDC Lib "GDI32" (ByVal hDC As Integer) As
Integer
Private Declare Function DeleteObject Lib "GDI32" (ByVal hObj As Integer) As
Integer
Private Declare Function GetCursorInfo Lib "User32.dll" (ByRef pCI As
CursorInfo) As Long
Private Declare Function GetCursorPos Lib "User32.dll" (ByVal lpPoint As
PointAPI) As Long
Private Declare Function DrawIconEx Lib "User32.dll" (ByVal hDC As Long, _
ByVal xLeft As Long, ByVal yTop As Long, ByVal hIcon As Long, _
ByVal cxWidth As Long, ByVal cyWidth As Long, ByVal istepIfAniCur As Long, _
ByVal hbrFlickerFreeDraw As Long, ByVal diFlags As Long) As Long
Private Const SRCCOPY As Integer = &HCC0020
Private Const HORIZRES As Integer = 8
Private Const VERTRES As Integer = 10
Private Const CURSOR_SHOWING As Long = &H1
Private Const DI_NORMAL As Long = &H3
Private Structure PointAPI
Dim X As Long
Dim Y As Long
End Structure
Private Structure CursorInfo
Dim cbSize As Long
Dim flags As Long
Dim hCursor As Long
Dim ptScreenPos As PointAPI
End Structure
Private oBackground As System.Drawing.Bitmap
Public Sub CaptureScreen()
Dim hSDC, hMDC As Integer
Dim hBMP, hBMPOld As Integer
Dim CurInf As CursorInfo
Dim CurPos As PointAPI
Dim FW As Integer 'Width
Dim FH As Integer 'Height
Try
hSDC = CreateDC("DISPLAY", "", "", "")
hMDC = CreateCompatibleDC(hSDC)
FW = GetDeviceCaps(hSDC, HORIZRES)
FH = GetDeviceCaps(hSDC, VERTRES)
hBMP = CreateCompatibleBitmap(hSDC, FW, FH)
hBMPOld = SelectObject(hMDC, hBMP)
Call BitBlt(hMDC, 0, 0, FW, FH, hSDC, 0, 0, SRCCOPY)
Call DeleteDC(hSDC)
CurInf.cbSize = Len(CurInf)
Call GetCursorInfo(CurInf)
If (CurInf.flags And CURSOR_SHOWING) Then
Call GetCursorPos(CurPos)
Call DrawIconEx(hMDC, CurPos.X, CurPos.Y, _
CurInf.hCursor, 0, 0, 0, False, DI_NORMAL)
End If
Call SelectObject(hMDC, hBMPOld)
Call DeleteDC(hMDC)
oBackground = System.Drawing.Image.FromHbitmap(New IntPtr(hBMP))
DeleteObject(hBMP)
DeleteObject(hBMPOld)
'Seems to be a memory hole in fromHbitmap ....
'Code gets SLOW when not GC.Collect ing ... wierd.
GC.Collect()
Catch ex As Exception
Debug.WriteLine("General GDI ERROR: " & ex.Message.ToString)
End Try
End Sub
Public ReadOnly Property GetSizedScreen(ByVal s As System.Drawing.Size) As
System.Drawing.Bitmap
Get
Try
Return New System.Drawing.Bitmap(oBackground, s)
Catch ex As Exception
Debug.WriteLine("Error: ScreenCapture - GetSizedScreen")
End Try
End Get
End Property
End Class
"gregory_may" <None> wrote in message
news:ORjApd7...@tk2msftngp13.phx.gbl...
Mike D Sutton
> definition. I also moved the DeleteDC call you added until after the BitBlt
> call.
>
> There seems to be 2 problems with this code:
>
> 1) Nothing is happening in Call GetCursorInfo(CurInf).
The code was tested in VB6 before posting so it should work without problems. What's the return value on GetCursorInfo() and what
does GetLastError() return immediately after the call fails? Are you populating the structure size before passing it to
GetCursorInfo()? Have you re-declared the structure/call properly for VB.NET?
> 2) if I Omit the gc.collect, things slow down and there is a leak some place
> (I am OK having GC.Collect here, its just WEIRD the code needs the
> GC.Collect call to work at a reasonable speed).
I'm not a VB.NET developer so can't help you with that side of things (you may find more luck somewhere like
microsoft.public.dotnet.framework.drawing) however the documentation for the FromHbitmap() method specifically state that you
shouldn't delete the GDI Bitmap handle until after the GDI+ Bitmap object is destroyed. In the demo code I posted I actually
removed the DeleteObject() call which would create a GDI resource leak if you're not properly destroying it after your GDI+ Bitmap
object is being destroyed.
gregory_may
is no error, it seems to execute fine. But, below, it doesnt do anything to
the structure:
? GetCursorInfo(CurInf)
9222812402616107008
I guess its doing something, but cant tell what. Then I can execute the
following:
?curinf
{RealTimeJpegBroadcast.ScreenCapture.CursorInfo}
cbSize: 40
flags: 0
hCursor: 0
ptScreenPos: {RealTimeJpegBroadcast.ScreenCapture.PointAPI}
(CBSize got a value, but thats because we set it prior to calling this
function. Doesnt look like any of the structure got updated ....?)
?curinf.ptScreenPos
{RealTimeJpegBroadcast.ScreenCapture.PointAPI}
X: 0
Y: 0
(Doesnt look like it got the mouse either)
If you tested under VB6, I would guess the structure, but it looks identical
to your type:
Private Structure CursorInfo
Dim cbSize As Long
Dim flags As Long
Dim hCursor As Long
Dim ptScreenPos As PointAPI
End Structure
Any other thoughts?
"Mike D Sutton" <ED...@mvps.org> wrote in message
news:OqJv$IA4DH...@TK2MSFTNGP09.phx.gbl...
Mike D Sutton @ Work
> is no error, it seems to execute fine. But, below, it doesnt do anything to
> the structure:
>
> ? GetCursorInfo(CurInf)
>
> 9222812402616107008
That number is too large to fit in a 32-bit integer so I would assume your declare is incorrect. Follow up on a VB.NET group for
clarification on this issue.
> If you tested under VB6, I would guess the structure, but it looks identical
> to your type:
<snip>
If this is what you're using in VB.NET then you declares are indeed incorrect since a Long data type in VB.NET is a 64-bit integer
where as in VB6 it's a 32-bit integer (Why Microsoft felt the need to change it who knows but it needs to be taken into account as I
mentioned in my original post.) Again though, please follow up on a VB.NET group for language porting questions - they're very much
off-topic here.
gregory_may
Changing from Long to Integer did the trick!!! Thanks again!
g.
"Mike D Sutton @ Work" <ED...@mvps.org> wrote in message
news:uEOGmnF4...@TK2MSFTNGP11.phx.gbl...