Magnification Below 125% Default Win API (Between 101 - 124%)

Question

I am looking into the windows magnification api and I have been playing around with it, but I have a problem with the magnification defaults, Windows only allows you to increment in 25%'s at the lowest. Is it possible for me to increase this perhaps 1-5% at a time? Perhaps increase by one percent with the mouse scroll in and out?

Windows Lowest 25% Default][1]

Thanks in advance for your assistance.

    int xDlg = (int)((float)GetSystemMetrics(SM_CXSCREEN) * (1.0 - (1.0 / magnificationFactor)) / 2.0);
    int yDlg = (int)((float)GetSystemMetrics(SM_CYSCREEN) * (1.0 - (1.0 / magnificationFactor)) / 2.0);

    BOOL successSet = MagSetFullscreenTransform(magnificationFactor, xDlg, yDlg);
    if (successSet)
    {
        BOOL fInputTransformEnabled;
        RECT rcInputTransformSource;
        RECT rcInputTransformDest;

        if (MagGetInputTransform(&fInputTransformEnabled, &rcInputTransformSource, &rcInputTransformDest))
        {
            if (fInputTransformEnabled)
            {
                SetInputTransform(hwndDlg, fInputTransformEnabled);
            }                
        }
    }

successSet == false; when it isn't 1.1 anything lower fails and I realised 1.1 = 125% zoom.

Answer 1

Both MagSetFullscreenTransform and MagSetWindowTransform take float input arguments. There are no restrictions as far as the magnification factor resolution goes, as long as it is at least 1.0f and no larger than the upper bound.

Answer 2

There is no such limit in the magnification API. The limitations you see on-screen were chosen by the UI developer.