Capture The Screen ! My Code is fast but not working !

[Cooker]

I combained some codes from each of you to build a really fast screen monitor , but so far It did not work !

Module

Public Declare Function BitBlt Lib "gdi32" (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
Public Declare Function CreateCompatibleDC Lib "gdi32" (ByVal hDC As Long) As Long
Public Declare Function SelectObject Lib "gdi32" (ByVal hDC As Long, ByVal hObject As Long) As Long
Public Declare Function GetWindowDC Lib "user32" (ByVal hWnd As Long) As Long
Public Declare Function ReleaseDC Lib "user32" (ByVal hWnd As Long, ByVal hDC As Long) As Long


Public Declare Function VarPtrArray Lib "msvbvm50.dll" Alias "VarPtr" (Ptr() As Any) As Long
Public Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (pDst As Any, pSrc As Any, ByVal ByteLen As Long)
Public Declare Function GetObjectAPI Lib "gdi32" Alias "GetObjectA" (ByVal hObject As Long, ByVal nCount As Long, lpObject As Any) As Long

Form : MonitorScreen

Dim ProgramDC As Long
Dim ScreenDC As Long
Dim ImageDC As Long
Dim CapErr As Long

Option Explicit

Private Type SAFEARRAYBOUND
    cElements As Long
    lLbound As Long
End Type

Private Type SAFEARRAY2D
    cDims As Integer
    fFeatures As Integer
    cbElements As Long
    cLocks As Long
    pvData As Long
    Bounds(0 To 1) As SAFEARRAYBOUND
End Type

Private Type BITMAP
    bmType As Long
    bmWidth As Long
    bmHeight As Long
    bmWidthBytes As Long
    bmPlanes As Integer
    bmBitsPixel As Integer
    bmBits As Long
End Type

Public pic() As Byte
Dim sa As SAFEARRAY2D
Dim bmp As BITMAP
Dim r As Long, g As Long, b As Long
Dim i As Integer
Dim j As Integer
Dim errmsg As Integer



Private Sub Cap_Click()
Refresher.Interval = 42
End Sub
Private Sub Form_Load()
ProgramDC = MonitorScreen.hDC
ScreenDC = GetWindowDC(0)
ImageDC = ImgField.hDC
End Sub
Private Sub Pause_Click()
Refresher.Interval = 0
End Sub
Private Sub PrtComm_Click()
Prt.Show
Prt.PrtForm.Text = ""
For i = 1 To 240
For j = 1 To 320
Prt.PrtForm.Text = pic(i, j)
Next j
Next i

End Sub

Private Sub Refresher_Timer()
CapErr = BitBlt(ImageDC, 0, 0, 320, 240, ScreenDC, 33, 214, vbSrcCopy)

GetObjectAPI ImgField.Picture, Len(bmp), bmp
With sa
    .cbElements = 1
    .cDims = 2
    .Bounds(0).lLbound = 0
    .Bounds(0).cElements = bmp.bmHeight
    .Bounds(1).lLbound = 0
    .Bounds(1).cElements = bmp.bmWidthBytes
    .pvData = bmp.bmBits
End With

CopyMemory ByVal VarPtrArray(pic), VarPtr(sa), 4

End Sub

the result is sad , PIC array contains nothing !

Thanks a lot for reading my rewbie code at first place !

[Beacon]

i was going to post this for you b4 but hesitated becuase you wanted just the image box but hey:
This is just as fast perhaps better plus has less code to capture the screen.

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

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

Public Function SaveScreen(sFile As String) As Boolean
Dim sPic As IPictureDisp
On Error GoTo Errhandler
Clipboard.Clear
keybd_event VK_MENU, 0, 0, 0
DoEvents
keybd_event VK_SNAPSHOT, 1, 0, 0
DoEvents
keybd_event VK_MENU, 0, KEYEVENTF_KEYUP, 0
DoEvents
Set sPic = Clipboard.GetData(0)
SavePicture sPic, sFile
Clipboard.Clear
Set sPic = Nothing
SaveDesktop = True
Errhandler:
End Function

Usage:

Private Sub Command5_Click()
Form1.WindowState = 2
SaveScreen "c:\my_pic.bmp"
End Sub

Hows that?

[VIP3R]

I didn't even read your code but try executing the Print Screen button from code. That's really fast 2! lol and alot less coding!

[Beacon]

nope from memory if you use sendkeys to the printscrn button or ctrl + pntscrn it gives an error or doesnt work 1 or the other.

Thats why you gots to do like i have!

And if you want to put the screen capture straight into a image box you set the image boxes path to clipboard.

i.e image1.path = clipboard.getdata or something similar too that!

[Tygur]

Executing the Print Screen button is not the way to go. It uses the clipboard, and that can get annoying for the person using the program.

VB is a perfect example of this. I don't think anybody appreciates that VB clears the clipboard as it loads up. Do you really want your program to be just as annoying?

[Tygur]

Cooker, I've been looking at your code and I'm having troule figuring out what you're trying to do in the timer. What are you trying to get into the Pic array? What do you intend on doing to it after it gets filled with whatever has to go into it? Maybe there's another way of doing whatever youre trying to do.

[Beacon]

and whats wrong with my way tygur?
Simple easy!
Better than using bitblt!
I dont say clipboard stuff his uses the memory instead if i'm correct!

[Tygur]

Your way clears the clipboard, right?
If so, that's what's wrong. I would never want to use a program that has to clear the clipboard just to capture the screen.

[Beacon]

Doesnt have too i just put that there to be sure get rid of the lines of code clipboard.clear then use it if it's that worrying.
Still works.

[Cooker]

I wanted to save the colors into an array ...
So what is the point of saving it onto the harddisk at first place .

[Beacon]

As i said above You Dont Have To Save It!

You can always use clipboard.getdata and use that to put it into your array or whatever. It's how i save my screen captures thats all!

image1.picture = clipboard.getdata or something similar!

[Cooker]

Still , I don't think pressing the printscreen 24 times a second is a good Idea ...

[Tygur]

Beacon, your code takes away whatever was in the clipboard before you tried to capture the screen. Cooker's code is in a timer. If you put your code in a timer, you effectively render the clipboard useless.

Cooker, what you mean by "save the colors into an array"? Are you trying to store the image in a variable so you can show it someplace else (or save it)? If so, there are easier ways.

[Cooker]

My aim is real time screen analyzer that capture a part of the screen , analyze it , and output the result. I need the system to refresh really fast so the system will quickly respond to anything on the screen.
A array is need for the analysis