/// <summary>
/// Gets the DPI of the monitor nearest to a window
/// </summary>
/// <param name="hWnd">Handle to the window</param>
/// <returns>DPI of the monitor nearest to the window</returns>
private static DpiScale2 GetDpiForWindowFromNearestMonitor(IntPtr hWnd)
{
IntPtr hMon =
SafeNativeMethods.MonitorFromWindow(new HandleRef(IntPtr.Zero, hWnd), NativeMethods.MONITOR_DEFAULTTONEAREST);
uint dpiX, dpiY;
int hr = (int)UnsafeNativeMethods.GetDpiForMonitor(new HandleRef(IntPtr.Zero, hMon), MONITOR_DPI_TYPE.MDT_EFFECTIVE_DPI, out dpiX, out dpiY);
// Throw if FAILED(hr)
Marshal.ThrowExceptionForHR(hr);
return(DpiScale2.FromPixelsPerInch(dpiX, dpiY));
}
private static DpiScale2 GetSystemDpiFromDeviceCaps()
{
HandleRef hWndDesktop = new HandleRef(IntPtr.Zero, IntPtr.Zero);
HandleRef hDC = new HandleRef(IntPtr.Zero, UnsafeNativeMethods.GetDC(hWndDesktop));
if (hDC.Handle == IntPtr.Zero)
{
return(null);
}
try
{
int ppiX = UnsafeNativeMethods.GetDeviceCaps(hDC, NativeMethods.LOGPIXELSX);
int ppiY = UnsafeNativeMethods.GetDeviceCaps(hDC, NativeMethods.LOGPIXELSY);
return(DpiScale2.FromPixelsPerInch(ppiX, ppiY));
}
finally
{
UnsafeNativeMethods.ReleaseDC(hWndDesktop, hDC);
}
}
/// <summary>
/// Returns the System DPI by querying the value directly.
/// </summary>
/// <returns>The system DPI</returns>
private static DpiScale2 GetDpiForSystem()
{
uint dpi = SafeNativeMethods.GetDpiForSystem();
return(DpiScale2.FromPixelsPerInch(dpi, dpi));
}
/// <summary>
/// Gets a window's DPI by querying it directly
/// </summary>
/// <param name="hWnd">Handle to the window</param>
/// <returns>The DPI of the window</returns>
private static DpiScale2 GetDpiForWindow(IntPtr hWnd)
{
uint dpi = SafeNativeMethods.GetDpiForWindow(new HandleRef(IntPtr.Zero, hWnd));
return(DpiScale2.FromPixelsPerInch(dpi, dpi));
}