处理WM_NCPAINT"破坏"Vista/Aero上的DWM玻璃渲染

Question

我正在尝试创建一个窗口,WM_NCPAINT根据用户设置在具有Aero/Glass和自定义渲染帧(通过处理)之间切换.(Windows Vista).

DwmComposition已启用.我的应用程序提供了玻璃框架,但是一旦我切换设置以触发自定义WM_NCPAINT代码路径然后切换回使用DefWindowProc的WM_NCPAINT处理,原生框架现在永远停留在"Vista Basic"风格 - 它不再是半透明的标题按钮与普通的Aero/Glass按钮看起来不同.

我已经尝试了各种方法,从发送SWP_FRAMECHANGED到更改窗口样式,然后将其更改回来,隐藏它等等,但是一切都无济于事.似乎只要我处理WM_NCPAINT一个玻璃窗而不是推迟到DefWindowProc我的窗户就会永远"破碎".

我在MSDN上找到了一个C#/ WPF示例(代码点msdn dot microsoft dot com slash chrome),似乎表明只需要停止处理WM_NCPAINT并且玻璃会返回,但这似乎不适用于我自己的应用程序.

有没有办法干净地重置这个状态？我的代码是用C++编写的,住在这里:

http://bengoodger.dreamhosters.com/software/chrome/dwm/

#include <windows.h>
#include <dwmapi.h>

static const wchar_t* kWindowClass = L"BrokenGlassWindow";
static const wchar_t* kWindowTitle =
    L"BrokenGlass - Right click client area to toggle frame type.";
static const int kGlassBorderSize = 50;
static const int kNonGlassBorderSize = 40;

static bool g_glass = true;
bool IsGlass() {
  BOOL composition_enabled = FALSE;
  return DwmIsCompositionEnabled(&composition_enabled) == S_OK &&
      composition_enabled && g_glass;
}
void SetIsGlass(bool is_glass) {
  g_glass = is_glass;
}

void ToggleGlass(HWND hwnd) {
  SetWindowPos(hwnd, NULL, 0, 0, 0, 0,
               SWP_NOSIZE | SWP_NOMOVE | SWP_NOZORDER | SWP_FRAMECHANGED);
  RedrawWindow(hwnd, NULL, NULL, RDW_INVALIDATE | RDW_UPDATENOW);
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM w_param,
                         LPARAM l_param) {
  PAINTSTRUCT ps;
  HDC hdc;
  RECT wr;
  HBRUSH br;
  RECT* nccr = NULL;
  RECT dirty;
  RECT dirty_box;
  MARGINS dwmm = {0};
  WINDOWPOS* wp = NULL;

  switch (message) {
    case WM_CREATE:
      SetCursor(LoadCursor(NULL, IDC_ARROW));
      break;
    case WM_ERASEBKGND:
      return 1;
    case WM_PAINT:
      hdc = BeginPaint(hwnd, &ps);
      GetClientRect(hwnd, &wr);
      br = GetSysColorBrush(IsGlass() ? COLOR_APPWORKSPACE : COLOR_WINDOW);
      FillRect(hdc, &wr, br);
      EndPaint(hwnd, &ps);
      break;
    case WM_NCPAINT:
      if (IsGlass())
        return DefWindowProc(hwnd, message, w_param, l_param);
      GetWindowRect(hwnd, &wr);
      if (!w_param|| w_param == 1) {
        dirty = wr;
        dirty.left = dirty.top = 0;
      } else {
        GetRgnBox(reinterpret_cast<HRGN>(w_param), &dirty_box);
        if (!IntersectRect(&dirty, &dirty_box, &wr))
          return 0;
        OffsetRect(&dirty, -wr.left, -wr.top);
      }
      hdc = GetWindowDC(hwnd);
      br = CreateSolidBrush(RGB(255,0,0));
      FillRect(hdc, &dirty, br);
      DeleteObject(br);
      ReleaseDC(hwnd, hdc);
      break;
    case WM_NCACTIVATE:
      // Force paint our non-client area otherwise Windows will paint its own.
      RedrawWindow(hwnd, NULL, NULL, RDW_UPDATENOW);
      break;
    case WM_NCCALCSIZE:
      nccr = w_param ? &reinterpret_cast<NCCALCSIZE_PARAMS*>(l_param)->rgrc[0]
                     : reinterpret_cast<RECT*>(l_param);
      nccr->bottom -= IsGlass() ? kGlassBorderSize : kNonGlassBorderSize;
      nccr->right -= IsGlass() ? kGlassBorderSize : kNonGlassBorderSize;
      nccr->left += IsGlass() ? kGlassBorderSize : kNonGlassBorderSize;
      nccr->top += IsGlass() ? kGlassBorderSize : kNonGlassBorderSize;
      return WVR_REDRAW;
    case WM_RBUTTONDOWN:
      SetIsGlass(!g_glass);
      ToggleGlass(hwnd);
      break;
    case 0x31E: // WM_DWMCOMPOSITIONCHANGED:
      ToggleGlass(hwnd);
      break;    
    case 0xAE: // WM_NCUAHDRAWCAPTION:
    case 0xAF: // WM_NCUAHDRAWFRAME:
      return IsGlass() ? DefWindowProc(hwnd, message, w_param, l_param) : 0;
    case WM_WINDOWPOSCHANGED:
      dwmm.cxLeftWidth = kGlassBorderSize;
      dwmm.cxRightWidth = kGlassBorderSize;
      dwmm.cyTopHeight = kGlassBorderSize;
      dwmm.cyBottomHeight = kGlassBorderSize;
      DwmExtendFrameIntoClientArea(hwnd, &dwmm);
      break;
    case WM_DESTROY:
      PostQuitMessage(0);
      break;
    default:
      return DefWindowProc(hwnd, message, w_param, l_param);
  }
  return 0;
}

ATOM RegisterClazz(HINSTANCE instance) {
  WNDCLASSEX wcex = {0};
  wcex.cbSize = sizeof(wcex);
  wcex.style = CS_HREDRAW | CS_VREDRAW;
  wcex.lpfnWndProc = WndProc;
  wcex.hInstance = instance;
  wcex.lpszClassName = kWindowClass;
  return RegisterClassEx(&wcex);
}

int WINAPI WinMain(HINSTANCE instance, HINSTANCE, LPSTR, int show_command) {
  RegisterClazz(instance);
  HWND hwnd = CreateWindow(kWindowClass, kWindowTitle, WS_OVERLAPPEDWINDOW,
                           CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL,
                           instance, NULL);
  ShowWindow(hwnd, show_command);

  MSG msg;
  while (GetMessage(&msg, NULL, 0, 0)) {
    TranslateMessage(&msg);
    DispatchMessage(&msg);
  }
  return static_cast<int>(msg.wParam);
}

Answer 1

在Aero/Glass和自定义渲染帧之间切换时,您可以使用以下内容显式控制非客户区渲染策略:

DWMNCRENDERINGPOLICY policy = DWMNCRP_ENABLED; // DWMNCRP_DISABLED to toggle back
DwmSetWindowAttribute(hwnd, 
                      DWMWA_NCRENDERING_POLICY, 
                      (void*)&policy, 
                      sizeof(DWMNCRENDERINGPOLICY));