capture and stream..

hi all

i'm wondering if it's possible for me to capture certain amount of my screan at an interval, compress it and send it accross a socket?

kindof like vnc...

is it possible in vb?

thanks

it would not be easy to do, but, as you may have guessed, anything is possible. these programs tend to only send the data that has changed. this makes the job a lot easier, as usually not too much of the screen changes.
Of course, if you are transferring graphical data, as opposed to text, it is that much harder! :wave:

Capture a part of the screen is easy, sending it across a socket is also fairly simple. Then we come to the compression part... If you capture a part (or all) of the screen VB will store it as an uncompressed bitmap file. You could use some third party tool to compress it to a JPG or GIF before sending it but you probably need to store it as a file on disk first which also takes time.

Here's a quick example on how to store a part of the screen and show it in a picture box on a form.

VB Code:

Private Declare Function GetDesktopWindow _
 Lib "user32.dll" () As Long
 
Private Declare Function GetDC _
 Lib "user32.dll" ( _
 ByVal hwnd As Long) As Long
 
Private Declare Function ReleaseDC _
 Lib "user32.dll" ( _
 ByVal hwnd As Long, _
 ByVal hdc As Long) As Long
 
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 Sub Form_Load()
    With Picture1
        .ScaleMode = vbPixels 'for easier calculations
        .AutoRedraw = True
    End With
End Sub
 
Private Sub Command1_Click()
    Capture 10, 10
End Sub
 
Private Sub Capture(ByVal x As Long, ByVal y As Long)
    'We capture the screen at position x,y and
    'use the width and height of the picture box
    Dim hDesktopDC As Long, hDesktopWnd As Long
    
    hDesktopWnd = GetDesktopWindow
    hDesktopDC = GetDC(hDesktopWnd)
    With Picture1
        BitBlt .hdc, 0, 0, .ScaleWidth, .ScaleHeight, hDesktopDC, x, y, vbSrcCopy
        .Refresh
    End With
    ReleaseDC hDesktopWnd, hDesktopDC
End Sub

Cheers,

it's much easier sending text only.

Quote:

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Originally Posted by dglienna

it's much easier sending text only.

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That's true... and that a fish enjoys water is also true :)