static DpiHelper()
{
// Getting the Desktop, so we shouldn't have to release this DC.
// This could potentially throw if used in a service.
IntPtr desktop = NativeMethods.GetDC(IntPtr.Zero);
// Can get these in the static constructor. They shouldn't vary window to window,
// and changing the system DPI requires a restart.
int pixelsPerInchX = NativeMethods.GetDeviceCaps(desktop, DeviceCap.LOGPIXELSX);
int pixelsPerInchY = NativeMethods.GetDeviceCaps(desktop, DeviceCap.LOGPIXELSY);
_transformToDip = Matrix.Identity;
_transformToDip.Scale(96d / (double)pixelsPerInchX, 96d / (double)pixelsPerInchY);
_transformToDevice = Matrix.Identity;
_transformToDevice.Scale((double)pixelsPerInchX / 96d, (double)pixelsPerInchY / 96d);
}
public static Standard.SafeDC GetDC(IntPtr hwnd)
{
Standard.SafeDC dC = null;
try
{
dC = NativeMethods.GetDC(hwnd);
}
finally
{
if (dC != null)
{
dC.Hwnd = hwnd;
}
}
if (dC.IsInvalid)
{
Standard.HRESULT.E_FAIL.ThrowIfFailed();
}
return(dC);
}
public static SafeDC GetDC(IntPtr hwnd)
{
SafeDC dc = null;
try
{
dc = NativeMethods.GetDC(hwnd);
}
finally
{
if (dc != null)
{
dc.Hwnd = hwnd;
}
}
if (dc.IsInvalid)
{
// GetDC does not set the last error...
HRESULT.E_FAIL.ThrowIfFailed();
}
return(dc);
}
