winapi - 如何从 hWnd 获取显示器屏幕分辨率？

Question

如何从 hWnd 获取显示器屏幕分辨率？

我正在使用 hWnd，因为该窗口可以位于多个监视器中的任何一个上。

即 hWnd 上/左坐标位于屏幕分辨率为 800 x 600 的监视器上。

我用一种叫做 PL/B 的语言编程，它允许调用 Windows API。

可以使用哪些窗口 API？

Answer 1

这是一个适用于我的 C++ 代码示例：

HMONITOR monitor = MonitorFromWindow(hwnd, MONITOR_DEFAULTTONEAREST);
MONITORINFO info;
info.cbSize = sizeof(MONITORINFO);
GetMonitorInfo(monitor, &info);
int monitor_width = info.rcMonitor.right - info.rcMonitor.left;
int monitor_height = info.rcMonitor.bottom - info.rcMonitor.top;

Answer 2

user32函数MonitorFromWindow允许您传入一个 hwnd，并返回一个句柄到它所在的监视器（或默认值 - 有关详细信息，请参阅链接的 MSDN 文章）。有了它，您可以调用GetMonitorInfo来检索MONITORINFO 结构，其中包含详细说明其分辨率的 RECT。

有关更多详细信息，请参阅 MSDN 的多屏幕参考部分。

我会添加示例代码，但我不知道您引用的语言，也不知道 C# 示例代码对您有多大用处。如果您认为它会有所帮助，请告诉我，我会快速编写一些代码。

Answer 3

也有 GetSystemMetrics，在 msdn 上查看

Answer 4

下面是一些通过 P/Invoke 获取分辨率（以 DPI 表示）的 C# 代码：

public static void GetWindowDpi(IntPtr hwnd, out int dpiX, out int dpiY)
{
    var handle = MonitorFromWindow(hwnd, MonitorFlag.MONITOR_DEFAULTTOPRIMARY);

    GetDpiForMonitor(handle, MonitorDpiType.MDT_EFFECTIVE_DPI, out dpiX, out dpiY);
}

/// <summary>
/// Determines the function's return value if the window does not intersect any display monitor.
/// </summary>
[SuppressMessage("ReSharper", "IdentifierTypo")]
[SuppressMessage("ReSharper", "UnusedMember.Local")]
private enum MonitorFlag : uint
{
    /// <summary>Returns NULL.</summary>
    MONITOR_DEFAULTTONULL = 0,
    /// <summary>Returns a handle to the primary display monitor.</summary>
    MONITOR_DEFAULTTOPRIMARY = 1,
    /// <summary>Returns a handle to the display monitor that is nearest to the window.</summary>
    MONITOR_DEFAULTTONEAREST = 2
}

[DllImport("user32.dll")]
private static extern IntPtr MonitorFromWindow(IntPtr hwnd, MonitorFlag flag);

[SuppressMessage("ReSharper", "IdentifierTypo")]
[SuppressMessage("ReSharper", "UnusedMember.Local")]
private enum MonitorDpiType
{
    /// <summary>
    /// The effective DPI.
    /// This value should be used when determining the correct scale factor for scaling UI elements.
    /// This incorporates the scale factor set by the user for this specific display.
    /// </summary>
    MDT_EFFECTIVE_DPI = 0,
    /// <summary>
    /// The angular DPI.
    /// This DPI ensures rendering at a compliant angular resolution on the screen.
    /// This does not include the scale factor set by the user for this specific display.
    /// </summary>
    MDT_ANGULAR_DPI = 1,
    /// <summary>
    /// The raw DPI.
    /// This value is the linear DPI of the screen as measured on the screen itself.
    /// Use this value when you want to read the pixel density and not the recommended scaling setting.
    /// This does not include the scale factor set by the user for this specific display and is not guaranteed to be a supported DPI value.
    /// </summary>
    MDT_RAW_DPI = 2
}

[DllImport("user32.dll")]
private static extern bool GetDpiForMonitor(IntPtr hwnd, MonitorDpiType dpiType, out int dpiX, out int dpiY);

Answer 5

适用于高分辨率 2K 4K > 1920px 的显示器

void GetDesktopResolution(int* horizontal, int* vertical)
{

    HDC hScreenDC = GetDC(GetDesktopWindow());
    int width = GetDeviceCaps(hScreenDC, HORZRES);
    int height = GetDeviceCaps(hScreenDC, VERTRES);
    ReleaseDC(GetDesktopWindow(), hScreenDC);

    RECT desktop;
    const HWND hDesktop = GetDesktopWindow();
    GetWindowRect(hDesktop, &desktop);
    
    if (width > 2000)
    {
        const POINT ptZero = { 0, 0 };
        HMONITOR mon = MonitorFromPoint(ptZero, MONITOR_DEFAULTTOPRIMARY);

        DEVICE_SCALE_FACTOR f;// vers < win 8 = GetScaleFactorForDevice(DEVICE_PRIMARY);
        GetScaleFactorForMonitor(mon,&f);
        if (f > 110)
        {
            *horizontal = width * ((f+10) / 100.0);
            *vertical = height * ((f+10) / 100.0);
        }
        else
        {
            *horizontal = width;
            *vertical = height;
        }
    }
    else
    {
        *horizontal = desktop.right;
        *vertical = desktop.bottom;
    }
}

Answer 6

RECT windowsize;    // get the height and width of the screen
GetClientRect(hwnd, &windowsize);

int srcheight = windowsize.bottom;
int srcwidth = windowsize.right;