如何在WPF中获得DPI？
http://blogs.msdn.com/jaimer/archive/2007/03/07/getting-system-dpi-in-wpf-app.aspx似乎有效
PresentationSource source = PresentationSource.FromVisual(this);
double dpiX, dpiY;
if (source != null) {
dpiX = 96.0 * source.CompositionTarget.TransformToDevice.M11;
dpiY = 96.0 * source.CompositionTarget.TransformToDevice.M22;
}
var dpiXProperty = typeof(SystemParameters).GetProperty("DpiX", BindingFlags.NonPublic | BindingFlags.Static);
var dpiYProperty = typeof(SystemParameters).GetProperty("Dpi", BindingFlags.NonPublic | BindingFlags.Static);
var dpiX = (int)dpiXProperty.GetValue(null, null);
var dpiY = (int)dpiYProperty.GetValue(null, null);
使用.NET 4.6.2 Preview及更高版本，您可以调用VisualTreeHelper.GetDpi(Visual visual)。它返回一个DpiScale结构，它告诉你给定的Visual将被渲染的DPI。
我发现获得“真实”监视器dpi的唯一方法如下。所有其他提到的技术只是说96对大多数监视器来说都不正确。
public class ScreenInformations
{
public static uint RawDpi { get; private set; }
static ScreenInformations()
{
uint dpiX;
uint dpiY;
GetDpi(DpiType.RAW, out dpiX, out dpiY);
RawDpi = dpiX;
}
/// <summary>
/// Returns the scaling of the given screen.
/// </summary>
/// <param name="dpiType">The type of dpi that should be given back..</param>
/// <param name="dpiX">Gives the horizontal scaling back (in dpi).</param>
/// <param name="dpiY">Gives the vertical scaling back (in dpi).</param>
private static void GetDpi(DpiType dpiType, out uint dpiX, out uint dpiY)
{
var point = new System.Drawing.Point(1, 1);
var hmonitor = MonitorFromPoint(point, _MONITOR_DEFAULTTONEAREST);
switch (GetDpiForMonitor(hmonitor, dpiType, out dpiX, out dpiY).ToInt32())
{
case _S_OK: return;
case _E_INVALIDARG:
throw new ArgumentException("Unknown error. See https://msdn.microsoft.com/en-us/library/windows/desktop/dn280510.aspx for more information.");
default:
throw new COMException("Unknown error. See https://msdn.microsoft.com/en-us/library/windows/desktop/dn280510.aspx for more information.");
}
}
//https://msdn.microsoft.com/en-us/library/windows/desktop/dd145062.aspx
[DllImport("User32.dll")]
private static extern IntPtr MonitorFromPoint([In]System.Drawing.Point pt, [In]uint dwFlags);
//https://msdn.microsoft.com/en-us/library/windows/desktop/dn280510.aspx
[DllImport("Shcore.dll")]
private static extern IntPtr GetDpiForMonitor([In]IntPtr hmonitor, [In]DpiType dpiType, [Out]out uint dpiX, [Out]out uint dpiY);
const int _S_OK = 0;
const int _MONITOR_DEFAULTTONEAREST = 2;
const int _E_INVALIDARG = -2147024809;
}
/// <summary>
/// Represents the different types of scaling.
/// </summary>
/// <seealso cref="https://msdn.microsoft.com/en-us/library/windows/desktop/dn280511.aspx"/>
public enum DpiType
{
EFFECTIVE = 0,
ANGULAR = 1,
RAW = 2,
}
我已经从2015年更新了我的答案。这里有一些实用程序代码，它使用Windows 10中的最新DPI函数（特别是GetDpiForWindow function，这是支持窗口/应用程序/进程的DPI_AWARENESS等的唯一方法），但是可以追溯到更早版本其中一个（每个显示器的dpi和桌面dpi）因此它仍然适用于Windows 7。
它不依赖于WPF，也不依赖于Winforms，仅限于Windows本身。
// note this class considers dpix = dpiy
public static class DpiUtilities
{
// you should always use this one and it will fallback if necessary
// https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-getdpiforwindow
public static int GetDpiForWindow(IntPtr hwnd)
{
var h = LoadLibrary("user32.dll");
var ptr = GetProcAddress(h, "GetDpiForWindow"); // Windows 10 1607
if (ptr == IntPtr.Zero)
return GetDpiForNearestMonitor(hwnd);
return Marshal.GetDelegateForFunctionPointer<GetDpiForWindowFn>(ptr)(hwnd);
}
public static int GetDpiForNearestMonitor(IntPtr hwnd) => GetDpiForMonitor(GetNearestMonitorFromWindow(hwnd));
public static int GetDpiForNearestMonitor(int x, int y) => GetDpiForMonitor(GetNearestMonitorFromPoint(x, y));
public static int GetDpiForMonitor(IntPtr monitor, MonitorDpiType type = MonitorDpiType.Effective)
{
var h = LoadLibrary("shcore.dll");
var ptr = GetProcAddress(h, "GetDpiForMonitor"); // Windows 8.1
if (ptr == IntPtr.Zero)
return GetDpiForDesktop();
int hr = Marshal.GetDelegateForFunctionPointer<GetDpiForMonitorFn>(ptr)(monitor, type, out int x, out int y);
if (hr < 0)
return GetDpiForDesktop();
return x;
}
public static int GetDpiForDesktop()
{
int hr = D2D1CreateFactory(D2D1_FACTORY_TYPE.D2D1_FACTORY_TYPE_SINGLE_THREADED, typeof(ID2D1Factory).GUID, IntPtr.Zero, out ID2D1Factory factory);
if (hr < 0)
return 96; // we really hit the ground, don't know what to do next!
factory.GetDesktopDpi(out float x, out float y); // Windows 7
Marshal.ReleaseComObject(factory);
return (int)x;
}
public static IntPtr GetDesktopMonitor() => GetNearestMonitorFromWindow(GetDesktopWindow());
public static IntPtr GetShellMonitor() => GetNearestMonitorFromWindow(GetShellWindow());
public static IntPtr GetNearestMonitorFromWindow(IntPtr hwnd) => MonitorFromWindow(hwnd, MONITOR_DEFAULTTONEAREST);
public static IntPtr GetNearestMonitorFromPoint(int x, int y) => MonitorFromPoint(new POINT { x = x, y = y }, MONITOR_DEFAULTTONEAREST);
private delegate int GetDpiForWindowFn(IntPtr hwnd);
private delegate int GetDpiForMonitorFn(IntPtr hmonitor, MonitorDpiType dpiType, out int dpiX, out int dpiY);
private const int MONITOR_DEFAULTTONEAREST = 2;
[DllImport("kernel32", CharSet = CharSet.Auto, SetLastError = true)]
private static extern IntPtr LoadLibrary(string lpLibFileName);
[DllImport("kernel32", CharSet = CharSet.Ansi, SetLastError = true)]
private static extern IntPtr GetProcAddress(IntPtr hModule, string lpProcName);
[DllImport("user32")]
private static extern IntPtr MonitorFromPoint(POINT pt, int flags);
[DllImport("user32")]
private static extern IntPtr MonitorFromWindow(IntPtr hwnd, int flags);
[DllImport("user32")]
private static extern IntPtr GetDesktopWindow();
[DllImport("user32")]
private static extern IntPtr GetShellWindow();
[StructLayout(LayoutKind.Sequential)]
private partial struct POINT
{
public int x;
public int y;
}
[DllImport("d2d1")]
private static extern int D2D1CreateFactory(D2D1_FACTORY_TYPE factoryType, [MarshalAs(UnmanagedType.LPStruct)] Guid riid, IntPtr pFactoryOptions, out ID2D1Factory ppIFactory);
private enum D2D1_FACTORY_TYPE
{
D2D1_FACTORY_TYPE_SINGLE_THREADED = 0,
D2D1_FACTORY_TYPE_MULTI_THREADED = 1,
}
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown), Guid("06152247-6f50-465a-9245-118bfd3b6007")]
private interface ID2D1Factory
{
int ReloadSystemMetrics();
[PreserveSig]
void GetDesktopDpi(out float dpiX, out float dpiY);
// the rest is not implemented as we don't need it
}
}
public enum MonitorDpiType
{
Effective = 0,
Angular = 1,
Raw = 2,
}
使用GetDeviceCaps函数：
static void Main(string[] args)
{
// 1.25 = 125%
var dpi = GetDpi() ;
}
[DllImport("user32.dll")]
public static extern int ReleaseDC(IntPtr hWnd, IntPtr hDC);
[DllImport("user32.dll")]
public static extern IntPtr GetDC(IntPtr hwnd);
[DllImport("gdi32.dll")]
static extern int GetDeviceCaps(IntPtr hdc, int nIndex);
private static float GetDpi()
{
IntPtr desktopWnd = IntPtr.Zero;
IntPtr dc = GetDC(desktopWnd);
var dpi = 100f;
const int LOGPIXELSX = 88;
try
{
dpi = GetDeviceCaps( dc, LOGPIXELSX);
}
finally
{
ReleaseDC(desktopWnd, dc);
}
return dpi / 96f;
}
这就是我在WPF中获得“比例因子”的方式我的笔记本电脑的分辨率是1920x1440。
int resHeight = System.Windows.Forms.Screen.PrimaryScreen.Bounds.Height; // 1440
int actualHeight = SystemParameters.PrimaryScreenHeight; // 960
double ratio = actualHeight / resHeight;
double dpi = resHeigh / actualHeight; // 1.5 which is true because settings says 150%
2017年1月25日下午3:54
“从桌面应用程序调用Windows 10 API”和
https://docs.microsoft.com/en-us/uwp/api/windows.devices.display.displaymonitor
“显示器类”
命名空间：Windows.Devices.Display程序集：Windows.Devices.Display.dll，Windows.dll
提供有关连接到系统的显示器设备的信息。
这些数据包括来自监视器的扩展显示标识数据（EDID，这是几乎所有监视器用于提供支持模式和一般设备信息的描述的行业标准显示描述符块）和DisplayID（这是一个较新的行业标准）的常用信息。它提供了EDID的超集。
原始DpiX 获取监视器的物理水平DPI（基于监视器的本机分辨率和物理大小）。
原始DpiY 获取监视器的物理垂直DPI（基于监视器的本机分辨率和物理大小）。
从2006年开始的Windows中的基本监视器信息
https://docs.microsoft.com/en-us/windows/desktop/wmicoreprov/msmonitorclass
MSMonitorClass类
WmiMonitorRawEEdidV1Block类
WmiMonitorBasicDisplayParams类
MaxHorizontalImageSize ( EDID byte 21 )
MaxVerticalImageSize ( EDID byte 22 )
（EDID中的尺寸在EDID详细定时描述符中以厘米为单位，以毫米为单位
12水平图像尺寸，mm，8 lsbits（0-4095 mm，161 in） 13垂直图像尺寸，mm，8 lsbits（0-4095 mm，161 in） 14位7-4水平图像尺寸，mm，4 msbits 位3-0垂直图像尺寸，mm，4 msbits
)
和