/// <summary>
/// Retrieve the DPI value for the supplied window handle
/// </summary>
/// <param name="hWnd">IntPtr</param>
/// <returns>dpi value</returns>
public static uint GetDpi(IntPtr hWnd)
{
if (!User32Api.IsWindow(hWnd))
{
return(DpiHandler.DefaultScreenDpi);
}
// Use the easiest method, but this only works for Windows 10
if (WindowsVersion.IsWindows10OrLater)
{
return(GetDpiForWindow(hWnd));
}
// Use the second easiest method, but this only works for Windows 8.1 or later
if (WindowsVersion.IsWindows81OrLater)
{
var hMonitor = User32Api.MonitorFromWindow(hWnd, MonitorFrom.DefaultToNearest);
// ReSharper disable once UnusedVariable
if (GetDpiForMonitor(hMonitor, MonitorDpiType.EffectiveDpi, out var dpiX, out var dpiY))
{
return(dpiX);
}
}
// Fallback to the global DPI settings
using (var hdc = SafeDeviceContextHandle.FromHWnd(hWnd))
{
if (hdc == null)
{
return(DpiHandler.DefaultScreenDpi);
}
return((uint)Gdi32Api.GetDeviceCaps(hdc, DeviceCaps.LOGPIXELSX));
}
}
/// <summary>
/// Retrieve the DPI value for the supplied window handle
/// </summary>
/// <param name="hWnd">IntPtr</param>
/// <returns>dpi value</returns>
public static int GetDpi(IntPtr hWnd)
{
// Use the easiest method, but this only works for Windows 10
if (WindowsVersion.IsWindows10OrLater)
{
return(GetDpiForWindow(hWnd));
}
// Use the second easiest method, but this only works for Windows 8.1 or later
if (WindowsVersion.IsWindows81OrLater)
{
var hMonitor = User32Api.MonitorFromWindow(hWnd, MonitorFrom.DefaultToNearest);
uint dpiX;
uint dpiY;
if (GetDpiForMonitor(hMonitor, MonitorDpiType.EffectiveDpi, out dpiX, out dpiY))
{
return((int)dpiX);
}
}
// Fallback to the global DPI settings
using (var hdc = SafeDeviceContextHandle.FromHWnd(hWnd))
{
return(Gdi32Api.GetDeviceCaps(hdc, DeviceCaps.LOGPIXELSX));
}
}
public void TestSafeDeviceContextHandle_IntPtrZero()
{
using (var safeDeviceContextHandle = SafeDeviceContextHandle.FromHWnd(IntPtr.Zero))
{
Assert.Null(safeDeviceContextHandle);
}
}
