如何在无边框表单上创建模糊玻璃效果？

Question

如何在无边框表单上绘制平滑的模糊玻璃效果？我已经尝试了Image Processing for Dummies with C and GDI+ 页面上列出的代码，但我确定这不是我应该使用的。再多的玩弄它并没有产生任何我所追求的结果。

这基本上是我想要实现的目标：

Answer 1

我假设您正在谈论 Windows 7 / Vista，并且您希望以相同的方式实现某些 MS 程序具有的模糊透明区域。对于一般情况，您确实需要一些我不会介绍的图像处理。

对于我上面提到的情况，您不应该自己做这件事 - 这有点重新发明轮子。基本上你可以使用窗口管理器来实现这个效果（叫做aero glass），使用本文介绍的方法：http://msdn.microsoft.com/en-us/magazine/cc163435.aspx

我目前只有一台 Windows 8 机器（默认情况下他们取消了这种模糊和透明度），所以我没有测试环境来检查这一点。我将在本周晚些时候找到一个并设置一个示例代码来执行此操作，

使用桌面窗口管理器后，如果您只想模糊顶部（如图像中的部分），请使用 DwmExtendFrameIntoClientArea 将框架（默认为 aero 模糊）扩展到您的窗口中。对于自定义区域，使用 DwmEnableBlurBehindWindow

所以，如果这确实是您正在寻找的东西（Windows 7 / vista 的解决方案，与现有 MS 程序的工作方式相同），请告诉我，我稍后会更新代码。否则，如果您正在寻找通用解决方案（不仅仅是 windows vista / 7），请告诉我省去我编写此代码的工作...

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编辑：鉴于您选择手动制作效果，这里有一些基本代码可以帮助您入门

// Code was burrowed from:
//   http://stackoverflow.com/questions/19867402/how-can-i-use-enumwindows-to-find-windows-with-a-specific-caption-title
//   http://www.dotnetframework.org/default.aspx/4@0/4@0/DEVDIV_TFS/Dev10/Releases/RTMRel/ndp/fx/src/CommonUI/System/Drawing/NativeMethods@cs/1305376/NativeMethods@cs
//   http://stackoverflow.com/questions/7292757/how-to-get-screenshot-of-a-window-as-bitmap-object-in-c
//   http://stackoverflow.com/questions/798295/how-can-i-use-getnextwindow-in-c */

public static class WinAPI
{
   public delegate bool EnumWindowsProc(IntPtr hWnd, IntPtr lParam);

    [StructLayout(LayoutKind.Sequential)]
    public struct RECT
    {
        public int left;
        public int top;
        public int right;
        public int bottom;
    };

    public enum GW
    {
        GW_HWNDFIRST = 0,
        GW_HWNDLAST = 1,
        GW_HWNDNEXT = 2,
        GW_HWNDPREV = 3,
        GW_OWNER = 4,
        GW_CHILD = 5,
        GW_ENABLEDPOPUP = 6
    }

    [DllImport("User32.dll")]
    public static extern bool EnumWindows(EnumWindowsProc lpEnumFunc, IntPtr lParam);

    [DllImport("User32.dll", CharSet = CharSet.Unicode)]
    public static extern int GetWindowText(IntPtr hWnd, StringBuilder strText, int maxCount);

    [DllImport("User32.dll")]
    public static extern int GetWindowTextLength(IntPtr hWnd);

    [DllImport("User32.dll")]
    public static extern bool IsWindowVisible(IntPtr hWnd);

    [DllImport("User32.dll")]
    public static extern bool IsIconic(IntPtr hWnd);

    [DllImport("User32.dll")]
    public static extern bool GetClientRect(IntPtr hWnd, ref RECT lpRect);

    [DllImport("User32.dll")]
    public static extern bool GetWindowRect(IntPtr hWnd, ref RECT lpRect);

    [DllImport("User32.dll")]
    public static extern IntPtr GetDesktopWindow();

    [DllImport("User32.dll")]
    public static extern IntPtr GetTopWindow(IntPtr hWnd);

    public static IntPtr GetNextWindow(IntPtr hWnd, GW wCmd)
    {
        return GetWindow(hWnd, wCmd);
    }

    public static IntPtr GetWindow(IntPtr hWnd, GW wCmd)
    {
        return GetWindow(hWnd, (uint)wCmd);
    }

    [DllImport("User32.dll")]
    private static extern IntPtr GetWindow(IntPtr hWnd, uint wCmd);

    [DllImport("User32.dll")]
    public static extern bool PrintWindow(IntPtr hWnd, IntPtr hdcBlt, uint nFlags);

    [DllImport("User32.dll")]
    public static extern IntPtr GetDC(IntPtr hWnd);

    [DllImport("Gdi32.dll")]
    public static extern bool DeleteDC(IntPtr hdc);

    [DllImport("User32.dll")]
    public static extern IntPtr GetWindowDC(IntPtr hWnd);

    [DllImport("User32.dll")]
    public static extern int ReleaseDC(IntPtr hWnd, IntPtr hdc);

    [DllImport("User32.dll")]
    public static extern int GetWindowRgn(IntPtr hWnd, IntPtr hRgn);

    [DllImport("Gdi32.dll")]
    public static extern IntPtr CreateCompatibleDC(IntPtr hWnd);

    [DllImport("Gdi32.dll")]
    public static extern IntPtr CreateCompatibleBitmap(IntPtr hdc, int width, int height);

    [DllImport("Gdi32.dll")]
    public static extern IntPtr CreateBitmap(int width, int height, uint cPlanes, uint cBitsPerPel, IntPtr lpvBits);

    [DllImport("Gdi32.dll")]
    public static extern bool DeleteObject(IntPtr hGdiObj);

    [DllImport("Gdi32.dll")]
    public static extern bool SelectObject(IntPtr hdc, IntPtr hGdiObj);

    [DllImport("Gdi32.dll")]
    public static extern IntPtr CreateRectRgn(int nLeftRect, int nTopRect, int nRightRect, int nBottomRect);

    public static StringBuilder GetWindowText(IntPtr hWnd)
    {
        int length = GetWindowTextLength(hWnd);
        // Add another place to allow null terminator
        StringBuilder text = new StringBuilder(length + 1);
        GetWindowText(hWnd, text, length + 1);
        return text;    
    }

    public static bool IsWindowReallyVisible(IntPtr hWnd)
    {
        if (!IsWindowVisible(hWnd) || IsIconic(hWnd))
            return false;
        RECT area = new RECT();
        if (!GetWindowRect(hWnd, ref area))
            return true;
        if (area.left == area.right || area.bottom == area.top)
            return false;
        return true;
    }

    public enum RegionFlags
    {
        ERROR = 0,
        NULLREGION = 1,
        SIMPLEREGION = 2,
        COMPLEXREGION = 3,
    } 

}

public class ScreenShot
{
    public static List<IntPtr> GetAllWindows(Func<IntPtr, bool> filter, Func<IntPtr, bool> stop)
    {
        List<IntPtr> result = new List<IntPtr>();

        WinAPI.EnumWindows((wnd, param) =>
        {
            bool relevant = filter(wnd);
            if (relevant)
                result.Add(wnd);
            bool shouldStop = stop(wnd);
            if (shouldStop)
                Console.WriteLine("Stop");
            return !shouldStop;
        }, IntPtr.Zero);

        return result;
    }

    public static IEnumerable<IntPtr> GetWindowsByOrder(Func<IntPtr, bool> filter)
    {
        List<IntPtr> skip = new List<IntPtr>();
        List<IntPtr> result = new List<IntPtr>();
        IntPtr desktop = WinAPI.GetDesktopWindow();

        for (IntPtr wnd = WinAPI.GetTopWindow(IntPtr.Zero); wnd != IntPtr.Zero; wnd = WinAPI.GetNextWindow(wnd, WinAPI.GW.GW_HWNDNEXT))
        {
            if (result.Contains(wnd) || skip.Contains(wnd))
                break;
            else if (filter(wnd))
                result.Add(wnd);
            else
                skip.Add(wnd);
        }

        result.Add(desktop);
        return result;
    }

    public static Image GetScreenshot(IntPtr hWnd)
    {
        IntPtr hdcScreen = WinAPI.GetDC(hWnd);
        IntPtr hdc = WinAPI.CreateCompatibleDC(hdcScreen);
        WinAPI.RECT area = new WinAPI.RECT();

        WinAPI.GetWindowRect(hWnd, ref area);

        IntPtr hBitmap = WinAPI.CreateCompatibleBitmap(hdcScreen, area.right - area.left, area.bottom - area.top);
        WinAPI.SelectObject(hdc, hBitmap);

        WinAPI.PrintWindow(hWnd, hdc, 0);

        Image resultOpaque = Image.FromHbitmap(hBitmap);

        WinAPI.DeleteObject(hBitmap);
        WinAPI.DeleteDC(hdc);

        IntPtr hRegion = WinAPI.CreateRectRgn(0, 0, 0, 0);
        WinAPI.RegionFlags f = (WinAPI.RegionFlags) WinAPI.GetWindowRgn(hWnd, hRegion);
        Region region = Region.FromHrgn(hRegion);
        WinAPI.DeleteObject(hRegion);

        Bitmap result = new Bitmap(resultOpaque.Width, resultOpaque.Height, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
        Graphics g = Graphics.FromImage(result);
        g.Clear(Color.Transparent);
        if (f != WinAPI.RegionFlags.ERROR)
            g.SetClip(region, System.Drawing.Drawing2D.CombineMode.Replace);
        if (f != WinAPI.RegionFlags.NULLREGION)
            g.DrawImageUnscaled(resultOpaque, 0, 0);

        g.Dispose();
        region.Dispose();
        resultOpaque.Dispose();

        return result;
    }

/* And now for the actual code of getting screenshots of windows */
var windows = ScreenShot.GetWindowsByOrder(this.WindowFilter).Intersect(ScreenShot.GetAllWindows(this.WindowFilter, (wnd) => false)).ToList();

int index = windows.IndexOf((IntPtr)this.Handle); /* Remove all the windows behind your windows */
if (index != -1)
    windows.RemoveRange(index, windows.Count - index + 1);

windows.Reverse();

/* Get the images of all the windows */
for (int i = 0; i < windows.Count; ++i )
{
    var window = windows[i];
    using (var img = ScreenShot.GetScreenshot(window))
    {
        // Get the actual position of the window
        // Draw it's image overlayed on the other windows 9have an accumulating image)
    }
}

这在哪里仍然有错误（在我的 Windows 8.1 测试套件上）？

• 我仍然在透明度方面遇到问题 - 在其剪切区域内为半透明的窗口仍会被漆成黑色
• 我有一些未知的黑色窗口（可能是透明的）仍然出现
• 任务栏无法正确绘制

Answer 2

Winform

使用像 DwmEnableBlurBehindWindow 这样的 Win API

    [DllImport("gdi32")]
    private static extern IntPtr CreateEllipticRgn(int nLeftRect, int nTopRect, int nRightRect, int nBottomRect);
    [DllImport("dwmapi")]
    private static extern int DwmEnableBlurBehindWindow(IntPtr hWnd, ref DwmBlurbehind pBlurBehind);
    public struct DwmBlurbehind
    {
        public int DwFlags;
        public bool FEnable;
        public IntPtr HRgnBlur;
        public bool FTransitionOnMaximized;
    }
    public Form1()
    {
        InitializeComponent();
    }
    private void Form1_Load(object sender, EventArgs e)
    {
        var hr = CreateEllipticRgn(0, 0, Width, Height);
        var dbb = new DwmBlurbehind {FEnable = true, DwFlags = 1, HRgnBlur = hr, FTransitionOnMaximized = false};
        DwmEnableBlurBehindWindow(Handle, ref dbb);
    }
    protected override void OnPaint(PaintEventArgs e)
    {
        e.Graphics.FillRectangle(new SolidBrush(Color.Black), new Rectangle(0, 0, Width, Height));
    }

示例 1：

示例 2：您可以更改画笔颜色（例如：DarkRed）以获得漂亮的效果

这里要注意的是，您可以选择一个适用的区域，并且您可以拥有超过 1 个。

Wpf

您可以使用same approach。

Wpf 对着色器有更好的支持，您可以添加模糊等效果，但性能更重。此外，您的图像很可能来自 WPF 和 Blend 创建的程序。

如果我没记错的话，你不能在纯色画笔上使用像模糊这样的着色器。因此，以下不会产生相同的效果。将背景设置为 50% 透明（Window 属性 AllowsTransparency="True" 和 WindowStyle="None"）

<Window.Background>
    <SolidColorBrush Opacity="0.5" Color="White"/>
</Window.Background>

原生玻璃窗

此处描述了 Wpf 支持：http://www.paulrohde.com/native-glass-with-wpf/

我用稍微不同的方法得到了以下结果：