如何获取 WPF 中的 DPI？

Question

如何获取 WPF 中的 DPI？

Answer 1

https://learn.microsoft .com/en-us/archive/blogs/jaimer/getting-system-dpi-in-wpf-app 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;
}

Answer 2

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);

Answer 3

使用 .NET 4.6.2 Preview 及更高版本，您可以调用 VisualTreeHelper.GetDpi（视觉视觉）。它返回 DpiScale< /code>结构，它告诉您将呈现或已经呈现给定 Visual 的 DPI。

Answer 4

我已经更新了 2015 年的答案。以下是一些使用 Windows 10 中最新 DPI 功能的实用程序代码（特别是 GetDpiForWindow 函数，这是支持窗口/应用程序/进程等的 DPI_AWARENESS 的唯一方法），但回退到较旧的方法（每个显示器的 dpi，和桌面 dpi），因此它应该仍然适用于 Windows 7。

它不依赖于 WPF 或 Winforms，仅依赖于 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://learn.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,
}

Answer 5

我发现获得“真实”显示器 dpi 的唯一方法如下。所有其他提到的技术都只是说 96，这对于大多数显示器来说是不正确的。

 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,
}

Answer 6

这就是我如何在 WPF 中获得“比例因子”。
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 my settings says my scale is 150%

Answer 7

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;
    }

Answer 8

您可以尝试使用 ManagementClass：

public static string GetDPI()
        {
            using (ManagementClass mc = new ManagementClass("Win32_DesktopMonitor"))
            {
                using (ManagementObjectCollection moc = mc.GetInstances())
                {

                    int PixelsPerXLogicalInch = 0; // dpi for x
                    int PixelsPerYLogicalInch = 0; // dpi for y

                    foreach (ManagementObject each in moc)
                    {
                        PixelsPerXLogicalInch = int.Parse((each.Properties["PixelsPerXLogicalInch"].Value.ToString()));
                        PixelsPerYLogicalInch = int.Parse((each.Properties["PixelsPerYLogicalInch"].Value.ToString()));
                    }
                    return PixelsPerXLogicalInch + "," + PixelsPerYLogicalInch;
                }
            }
        }

Answer 9

WPF 现在可以本机提供 DPI 信息。

您可以使用 VisualTreeHelper.GetDpi(Visual)。

有关桌面应用程序中 DPI 缩放的更多信息，请参阅 MSDN 中的这篇文章
高 DPI 桌面应用程序Windows 上的开发

Answer 10

有
https:// /blogs.windows.com/buildingapps/2017/01/25/calling-windows-10-apis-desktop-application/#FJtMAIFjbtXiLQAp.97

2017 年 1 月 25 日下午 3:54

“从桌面应用程序”
和

https://learn.microsoft.com/en -us/uwp/api/windows.devices.display.displaymonitor

“显示监视器类”

命名空间：Windows.Devices.Display Assemblies：Windows.Devices.Display.dll、Windows.dll

提供有关显示监视器设备的信息连接到系统。

这些数据包括来自显示器扩展显示识别数据（EDID，这是一种行业标准显示描述符块，几乎所有显示器都使用它来提供支持的模式和一般设备信息的描述）和 DisplayID（这是一种较新的行业标准）的常用信息。提供 EDID 的超集）。

原始 DpiX
获取显示器的物理水平 DPI（基于显示器的本机分辨率和物理尺寸）。

原始 DpiY
获取显示器的物理垂直 DPI（基于显示器的本机分辨率和物理尺寸）。

Answer 11

2006 年 Windows 中的基本显示器信息

https://learn.microsoft.com /en-us/windows/desktop/wmicoreprov/msmonitorclass

MSMonitorClass 类

WmiMonitorRawEEdidV1Block 类

WmiMonitorBasicDisplayParams 类

MaxHorizontalImageSize ( EDID byte 21 )

MaxVerticalImageSize ( EDID byte 22 )

（EDID 中的大小以厘米为单位，EDID 详细时序描述符

12 中的大小以毫米为单位 水平图像大小，毫米，8 lsbits（0– 4095 毫米，161 英寸)
13 垂直图像尺寸，毫米，8 lsbits（0–4095 毫米，161 英寸）
14 位 7–4 水平图像尺寸，毫米，4 msbits
位 3–0 垂直图像大小，毫米，4 msbits

)

和

https://social.msdn.microsoft.com/Forums/vstudio/en-US/e7bb9384-b343-4543-ac0f-c98b88a7196f/ wpf-wmi-just-get-an-empty-string