Enable/disable ClearType without logging out

Question

I need to enable/disable ClearType (or "Adjust the appearance and performance of Windows > Smooth edges of screen fonts") via cmd (or any script like VBS/JS) or from the registry without logging out or restarting Windows.

Maybe it's possible to enable ClearType only for one application.

Answer 1

Here's a PowerShell way to do it:

Set-ItemProperty 'HKCU:\Control Panel\Desktop\' -Name FontSmoothing -Value "2"

You'll need to log off and back on for it to take effect.

NOTE: strangely the setting doesn't show up as enabled in Performance Options, even though it's clearly turned on:

Answer 2

Just to add more options, I have the C# version, adding GetFontSmoothing to it.

    [DllImport("user32.dll", SetLastError = true)]
    static extern bool SystemParametersInfo(uint uiAction, uint uiParam, ref int pvParam, uint fWinIni);

    const uint SPI_GETFONTSMOOTHING = 74;
    const uint SPI_SETFONTSMOOTHING = 75;
    const uint SPI_UPDATEINI = 0x1;
    const UInt32 SPIF_UPDATEINIFILE = 0x1;

    private Boolean GetFontSmoothing()
    {
        bool iResult;
        int pv = 0;
        /* Call to systemparametersinfo to get the font smoothing value. */
        iResult = SystemParametersInfo(SPI_GETFONTSMOOTHING, 0, ref pv, 0);
        if (pv > 0)
        {
            //pv > 0 means font smoothing is on.
            return true;
        }
        else
        {
            //pv == 0 means font smoothing is off.
            return false;
        }
    }

    private void DisableFontSmoothing()
    {
        bool iResult;
        int pv = 0;
        /* Call to systemparametersinfo to set the font smoothing value. */
        iResult = SystemParametersInfo(SPI_SETFONTSMOOTHING, 0, ref pv, SPIF_UPDATEINIFILE);
        Console.WriteLine("Disabled: {0}", iResult);
    }

    private void EnableFontSmoothing()
    {
        bool iResult;
        int pv = 0;
        /* Call to systemparametersinfo to set the font smoothing value. */
        iResult = SystemParametersInfo(SPI_SETFONTSMOOTHING, 1, ref pv, SPIF_UPDATEINIFILE);
        Console.WriteLine("Enabled: {0}", iResult);
    }