Thread: DrawDIB Problem

  1. #1
    nisar
    Guest

    DrawDIB Problem

    hello friends

    I am using DrawDIB to draw a Bitmap. If the size of the Bitmap increases. The scrolls become very slow. If the size oif the map is small then horizontal and vertical scrolling works fine. How can i load a large bitmap without effecting the scrolls.

  2. #2
    train spotter
    Join Date
    Aug 2001
    Location
    near a computer
    Posts
    3,868
    Try experimenting with these;

    How are you drawing the image to the screen? BitBlt() or StretchBlt()

    Using a screen buffer (double buffer) system?

    Trying to scroll and draw to the screen at the same time, small increment at a time?

    Or calculating the WHOLE scroll distance then doing the drawing?

    Handling WM_ERASEBKGND msg's?

    Using InvalidateRect() with the bErase set to TRUE?

    Using GetUpdateRect() before your call to BeginPaint() to reduce the area draw?
    "Man alone suffers so excruciatingly in the world that he was compelled to invent laughter."
    Friedrich Nietzsche

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    George Best

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