Win32:如何使投影荣誉非矩形“分层"窗口? [英] Win32: How to make drop shadow honor non-rectangular Layered window?

问题描述

我创建了分层窗口，方法是添加 WS_EX_LAYERED 扩展样式:

i've created a layered window by adding the the WS_EX_LAYERED extended style:

wndClass.ExStyle = wndClass.ExStyle | WS_EX_LAYERED;

Windows将使用黑色作为色度键颜色值.我要留下一个大的黑色边框，以使问题显而易见:

Windows will use black as the chroma key color value. i'm going to leave a large border of black to make the problem obvious:

在构建窗口之后，我告诉它使用黑色作为色度键颜色:

After the window is constructed, i tell it to use black as a chroma-key color:

SetLayeredWindowAttributes(hwnd, 0x00000000, 255, LWA_COLORKEY);

现在，弹出分层窗口显示为部分透明:

Now the popup layered window appears partially transparent:

问题是最后一步.我想使用 CS_DROPSHADOW 类样式，可用从Windows XP开始，要创建阴影:

The problem is the final step. i want to use CS_DROPSHADOW class style, available since Windows XP, to create a drop-shadow:

wndClass.Style = wndClass.Style | CS_DROPSHADOW;

出现阴影，但阴影围绕原始矩形窗口，并且未考虑分层窗口提供的窗口透明度:

The drop shadow appears, but the shadow surrounds the original rectangular window, and doesn't take into account the window's transparency provided by the layered window:

有人知道我错过了什么神奇的选择，这会使投影效果尊重非矩形分层窗口吗?

Does anyone know what magical option i've missed somewhere that will make the drop shadow honor the non-rectangular layered window?

此问题出现的另一个示例是当您不包括6px填充/边距时. Windows®绘制的提示窗口主题是非矩形的.这会在窗口透明的地方留下一个小的可见间隙，但不会出现阴影:

Another example of where this issue appears is when you don't include the 6px padding/margin. The hint window as drawn by Windows® themes is non-rectangular. This leaves a small visible gap where the window is transparent, but the drop shadow does not appear:

从Internet Explorer的此提示中可以看到，Microsoft设法使它起作用:

Microsoft has managed to make it work, as you can see from this hint from Internet Explorer:

更靠近Windows tooltips类提示窗口.使用 SpyXX -我可以获取其窗口矩形和类样式:

Looking closer at a Windows tooltips class hint window. Using SpyXX - i can get its window rect, and class styles:

SpyXX说:

Rectangle:     (440, 229)-(544, 249), 104x20
Restored Rect: (440, 229)-(544, 249), 104x20
Client Rect:   (0, 0)-(104, 20), 104x20

因此，所有指向窗口本身的像素均为104x20像素，而阴影位于窗口本身之外. (与CS_DROPSHADOW一致.)

So everything points to the window itself being 104x20 pixels, with the drop shadow outside the window itself. (Which is consistent with CS_DROPSHADOW.)

接下来，我可以看看tooltips窗口类的样式:

Next i can look at the styles of the tooltips window class:

Windows Styles:     94000001

    WS_POPUP        80000000
    WS_VISIBLE      10000000
    WS_CLIPSIBLINGS  4000000
    TTS_ALWAYSTIP          1

Extended Styles:    00080088

    WS_EX_LAYERED      80000
    WS_EX_TOOLWIN         80
    WS_EX_TOPMOST          8

有趣的是，它不使用 CS_SAVEBITS (0x800);这对于短寿命的小型窗口很有用.

Interestingly, it doesn't use CS_SAVEBITS (0x800); which is useful for small, short-lived, windows.

它也不使用CS_DROPSHADOW(0x20000).所以现在我想知道它是如何在自己的窗口之外绘制的?

Nor does it use CS_DROPSHADOW (0x20000). So now i wonder how is it drawing outside its own window?

注意:透明的分层窗口被记录为区域上的首选技术.

Note: Transparent layered windows is documented as the preferred technique over regions.

分层Windows已出现在Windows 2000中.XP中添加了CS_DropShadow.

Layered Windows have been around with Windows 2000. CS_DropShadow was added with XP.

推荐答案

文档记录了透明分层窗口是区域上的首选技术.

Transparent layered windows is documented as the preferred technique over regions.

但是，CS_DROPSHADOW 确实注意区域.如果您使用某个区域裁剪或以其他方式塑造窗口，则阴影将遵循新轮廓.

However, CS_DROPSHADOW does pay attention to regions. If you crop or otherwise shape your window using a region, the drop-shadow will follow the new outline.

幸运的是，您可以使用具有分层窗口的区域，并将两者结合起来即可得到您想要的效果.

Fortunately, you can use regions with layered windows, and by combining the two get the effect you're looking for.

顺便说一句:tooltips_class32 确实使用CS_DROPSHADOW-您不会在窗口样式中看到它，因为它是类样式，而不是窗口样式.

BTW: tooltips_class32 does use CS_DROPSHADOW - you won't see it in the window styles because it's a class style, not a window style.

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