How to Programmatically Retrieve Windows Display Scaling Factor in C#?

Accessing Windows Display Settings in C#

Windows 7 and later versions provide a Control Panel setting allowing users to adjust text and UI element sizes. C# developers often need to retrieve this setting for dynamic application behavior.

A Practical Solution

Directly using graphics.DpiX and DeviceCap.LOGPIXELSX unexpectedly returns a fixed value (96 DPI) regardless of the actual scaling. To accurately determine the scaling factor, a different approach is necessary:

<code class="language-csharp">[DllImport("gdi32.dll")]
static extern int GetDeviceCaps(IntPtr hdc, int nIndex);

public enum DeviceCap
{
    VERTRES = 10,
    DESKTOPVERTRES = 117
}

private float GetScalingFactor()
{
    using (Graphics g = Graphics.FromHwnd(IntPtr.Zero))
    {
        IntPtr desktop = g.GetHdc();
        int logicalScreenHeight = GetDeviceCaps(desktop, (int)DeviceCap.VERTRES);
        int physicalScreenHeight = GetDeviceCaps(desktop, (int)DeviceCap.DESKTOPVERTRES);
        g.ReleaseHdc(desktop);
        return (float)physicalScreenHeight / logicalScreenHeight; // e.g., 1.25 for 125% scaling
    }
}</code>

This code snippet leverages GetDeviceCaps to compare logical and physical screen heights, providing a precise scaling factor. A result of 1.25, for instance, indicates a 125% scaling level.

The above is the detailed content of How to Programmatically Retrieve Windows Display Scaling Factor in C#?. For more information, please follow other related articles on the PHP Chinese website!