如何解决使用Direct2d和Win7是否可以使用透明窗口?
我的系统是Windows 7,我想将Direct2D用于工具包项目。
我想在窗口的某些部分中创建一个按像素透明/半透明的窗口(我们可以看到透明或半透明的窗口,这些窗口在我的窗口下方)。
我看过https://docs.microsoft.com/en-us/archive/msdn-magazine/2014/june/windows-with-c-high-performance-window-layering-using-the-windows-composition-engine(请参阅此网页最底部的图像),似乎有可能,但只能使用扩展的窗口样式WS_EX_NOREDIRECTIONBITMAP,该样式在Win7上不可用(仅从win8起)。
我尝试使用的渲染目标是带有预乘alpha的bgra和扩展的窗口样式WS_EX_COMPOSITED | WS_EX_TRANSPARENT没有运气
这是我的代码(相关的代码,即渲染目标和布局的创建,位于render()函数中):
#include <iostream>
#ifdef _WIN32_WINNT
# undef _WIN32_WINNT
#endif
#define _WIN32_WINNT 0x602
#include <d2d1.h>
static HINSTANCE instance = NULL;
static HWND win = NULL;
static ID2D1Factory *factory = NULL;
static ID2D1HwndRenderTarget *rt = NULL;
LRESULT CALLBACK _window_procedure(HWND window,UINT message,WPARAM window_param,LPARAM data_param);
static void
render()
{
RECT r;
HRESULT res;
/* render target */
GetClientRect(win,&r);
D2D1_SIZE_U size = D2D1::SizeU(r.right,r.bottom);
FLOAT dpix;
FLOAT dpiy;
factory->GetDesktopDpi(&dpix,&dpiy);
D2D1_RENDER_TARGET_PROPERTIES rtp;
rtp.type = D2D1_RENDER_TARGET_TYPE_DEFAULT;
rtp.pixelFormat.format = DXGI_FORMAT_B8G8R8A8_UNORM;
rtp.pixelFormat.alphaMode = D2D1_ALPHA_MODE_PREMULTIPLIED;
rtp.dpiX = dpix;
rtp.dpiY = dpiy;
rtp.usage = D2D1_RENDER_TARGET_USAGE_NONE;
rtp.minLevel = D2D1_FEATURE_LEVEL_10;
D2D1_HWND_RENDER_TARGET_PROPERTIES wrtp;
wrtp.hwnd = win;
wrtp.pixelSize = size;
wrtp.presentOptions = D2D1_PRESENT_OPTIONS_IMMEDIATELY;
res =factory->CreateHwndRenderTarget(rtp,wrtp,&rt);
if (FAILED(res))
{
std::cout << "CreateHwndRenderTarget failed" << std::endl;
return;
}
/* brush */
ID2D1SolidColorBrush *brush;
/* rgba */
const D2D1_COLOR_F color = D2D1::ColorF(0.5,0.5,0.5);
res = rt->CreateSolidColorBrush(color,&brush);
if (FAILED(res))
{
std::cout << "CreateSolidColorBrush failed" << std::endl;
return;
}
/* ellipse */
D2D1_ELLIPSE ellipse;
D2D1_SIZE_F sz = rt->GetSize();
const float x = sz.width / 2;
const float y = sz.height / 2;
const float radius = std::min(x,y);
ellipse = D2D1::Ellipse(D2D1::Point2F(x,y),radius,radius);
rt->BeginDraw();
rt->Clear( D2D1::ColorF(D2D1::ColorF::SkyBlue,0.5f) );
rt->FillEllipse(ellipse,brush);
rt->EndDraw();
}
LRESULT CALLBACK
_window_procedure(HWND window,LPARAM data_param)
{
switch (message)
{
case WM_CLOSE:
PostQuitMessage(0);
return 0;
case WM_KEYUP:
if (window_param == 'Q')
{
PostQuitMessage(0);
}
return 0;
/* GDI notifications */
case WM_PAINT:
{
RECT rect;
std::cout << "paint" << std::endl;
if (GetUpdateRect(window,&rect,FALSE))
{
PAINTSTRUCT ps;
BeginPaint(window,&ps);
render();
EndPaint(window,&ps);
}
return 0;
}
default:
return DefWindowProc(window,message,window_param,data_param);
}
}
int main()
{
/* class */
WNDCLASS wc;
instance = GetModuleHandle(NULL);
if (!instance)
return 1;
memset (&wc,sizeof (WNDCLASS));
wc.style = CS_HREDRAW | CS_VREDRAW;
wc.lpfnWndProc = _window_procedure;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = instance;
wc.hIcon = LoadIcon (NULL,IDI_APPLICATION);
wc.hCursor = LoadCursor (NULL,IDC_ARROW);
wc.hbrBackground = (HBRUSH)(1 + COLOR_BTNFACE);
wc.lpszMenuName = NULL;
wc.lpszClassName = "D2D";
if(!RegisterClass(&wc))
goto free_library;
/* Window */
int w;
int h;
RECT r;
DWORD style;
DWORD exstyle;
w = 640;
h = 480;
style = WS_OVERLAPPEDWINDOW | WS_SIZEBOX;
exstyle = 0;
exstyle |= WS_EX_COMPOSITED | WS_EX_TRANSPARENT;
//exstyle |= WS_EX_NOREDIRECTIONBITMAP;
r.left = 0;
r.top = 0;
r.right = w;
r.bottom = h;
if (!AdjustWindowRectEx(&r,style,FALSE,exstyle))
goto unregister_class;
win = CreateWindowEx(exstyle,"D2D","Test",100,r.right - r.left,r.bottom - r.top,NULL,instance,NULL);
if (!win)
goto unregister_class;
ShowWindow(win,SW_SHOWNORMAL);
/* factory */
if (FAILED(D2D1CreateFactory(D2D1_FACTORY_TYPE_SINGLE_THREADED,&factory)))
goto destroy_win;
/* msg loop */
while(1)
{
MSG msg;
BOOL ret;
ret = PeekMessage(&msg,PM_REMOVE);
if (ret)
{
do
{
if (msg.message == WM_QUIT)
goto beach;
TranslateMessage(&msg);
DispatchMessageW(&msg);
} while (PeekMessage(&msg,PM_REMOVE));
}
}
beach:
factory->Release();
DestroyWindow(win);
UnregisterClass("D2D",instance);
FreeLibrary(instance);
return 0;
destroy_win:
DestroyWindow(win);
unregister_class:
UnregisterClass("D2D",instance);
free_library:
FreeLibrary(instance);
return 1;
}
我也不想使用分层窗口。
有人知道在Windows 7上是否可以实现我想要的吗?
谢谢
解决方法
在 Win7 上可以有一个没有 WS_EX_LAYERED
样式的透明窗口,但它有一些缺点:
-
window 必须有
WS_POPUP
样式,否则如果 Windows 样式有玻璃,窗口的背景会模糊。 -
windows上的DWM(Desktop Window Manager)必须开启,否则windows会不透明
-
虽然窗口在视觉上是透明的,但鼠标点击不会穿过 100% 透明区域。也许有解决方案,但我不知道。
// Transparent window setup #include <dwmapi.h> #pragma comment(lib,"Dwmapi") // .... MARGINS margins = { -1 }; DwmExtendFrameIntoClientArea(m_hwnd,&margins); if (FAILED(D2D1CreateFactory(D2D1_FACTORY_TYPE_SINGLE_THREADED,&pFactory))) { return -1; } // ... hr = pFactory->CreateHwndRenderTarget( D2D1::RenderTargetProperties( D2D1_RENDER_TARGET_TYPE_DEFAULT,D2D1::PixelFormat(DXGI_FORMAT_UNKNOWN,D2D1_ALPHA_MODE_PREMULTIPLIED) ),D2D1::HwndRenderTargetProperties(m_hwnd,size),&pRenderTarget );
如果您的窗口不透明,您可能关闭了 DWM 或 Windows 没有设置区域样式。
https://weblogs.asp.net/kennykerr/direct2d-and-the-desktop-window-manager
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