Thread: Moving Cursor using mouse_event()

  1. #1
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    Unhappy Moving Cursor using mouse_event()

    i am trying to move mouse cursor by capturing finger coordinate in opencv. i am not able to move the cursor to maximum screen size which is 1366*768. my webcam resolution is 640*480. my mouse pointer moves only to half of the screen. i do not know why.
    This is my code segment. mouse_pointer.x and mouse_pointer.y are the coordinate of my fore-finger.The Mouse_move is not an opencv function.
    this is the function call:

    Code:
    Mouse_Move(((1366*mouse_pointer.x)/640),((768*mouse_pointer.y)/480));
    void Mouse_Move(DWORD dx,DWORD dy)
    {
    
    DWORD event=0;
    event = MOUSEEVENTF_ABSOLUTE|MOUSEEVENTF_MOVE;
    mouse_event(event, dx*65535/Get_ScreenWidth(), dy*65535/Get_ScreenHight(), 0, 0);
    }
    Last edited by Salem; 04-18-2012 at 11:19 AM. Reason: demungled the code

  2. #2
    and the hat of int overfl Salem's Avatar
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    > Mouse_Move(((1366*mouse_pointer.x)/640),((768*mouse_pointer.y)/480));
    What type are the .x, .y members?

    Unless they're DWORD, my guess is numeric overflow.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.

  3. #3
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    This is the function prototype.
    Mouse_Move(DWORD dx, DWORD dy);
    the .x and .y are integers. what am i supposed to do ?

  4. #4
    and the hat of int overfl Salem's Avatar
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    Are those 16-bit integers?

    Because you have numeric overflow if they are.

    Another thing to consider is where "0,0" is considered to be for the different things you have.
    If the image thinks 0,0 is the centre of the image, and the mouse coordinates have 0,0 at the top-left, then this is something you have to take into account.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.

  5. #5
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    they are 32-bit integers.

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