Win32 绘制RGB三原色图案

以前看到三原色的图案，一直很好奇是如何画出来。后来终于搞清楚了，其实很简单，实际上就是RGB三个分量的"位与"运算。

下面给出Win32绘制三原色图案的例子，特此记录在此：

 #include <windows.h>

 LRESULT CALLBACK WndProc(HWND,UINT,WPARAM,LPARAM);

 int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance,LPSTR lpCmdLine,int iCmdShow)
 {
     static TCHAR szAppName[]=TEXT("RGB_SRCPAINT");
     HWND hWnd;
     MSG msg;
     WNDCLASS wc= {sizeof(WNDCLASS)};
     wc.style=CS_HREDRAW|CS_VREDRAW;
     wc.lpfnWndProc=WndProc;
     wc.cbClsExtra=;
     wc.cbWndExtra=;
     wc.hInstance=hInstance;
     wc.hIcon=LoadIcon(NULL,IDI_APPLICATION);
     wc.hCursor=LoadCursor(NULL,IDC_ARROW);
     wc.hbrBackground=(HBRUSH)GetStockObject(WHITE_BRUSH);
     wc.lpszMenuName=NULL;
     wc.lpszClassName=szAppName;
     if(!RegisterClass(&wc)) {
         MessageBox(NULL,TEXT("error"),szAppName,MB_ICONERROR|MB_OK);
         return ;
     }
     hWnd=CreateWindow(szAppName,TEXT("RGB"),WS_OVERLAPPEDWINDOW,
                       ,,,,NULL,NULL,hInstance,NULL);

     //
     ShowWindow(hWnd,iCmdShow);
     UpdateWindow(hWnd);
     while(GetMessage(&msg,NULL,,)) {
         TranslateMessage(&msg);
         DispatchMessage(&msg);
     }
     return msg.wParam;
 }
 //
 void Circle(HDC dc,int ox,int oy,int r)
 {
     Ellipse(dc,ox-r,oy-r,ox+r,oy+r);
 }
 //
 LRESULT CALLBACK WndProc(HWND hWnd,UINT message,WPARAM wParam,LPARAM lParam)
 {
     //
     HDC hdc,hMemDC;
     HBITMAP hBitmap;
     HBRUSH hbrush;
     RECT rc= {,,,};
     PAINTSTRUCT ps;
     int ox=,oy=,r=;
     //
     switch (message) {
     case   WM_PAINT :
         hdc=BeginPaint(hWnd,&ps);
         //MemDC
         hMemDC = CreateCompatibleDC(hdc);
         hBitmap = CreateCompatibleBitmap(hdc,,);
         SelectObject(hMemDC,hBitmap);
         //ClearScreen with  Black
         hbrush = CreateSolidBrush(RGB(, , ));
         SelectObject(hMemDC,hbrush);
         FillRect(hdc,&rc,hbrush);
         //RED
         hbrush = CreateSolidBrush(RGB(, , ));
         SelectObject(hMemDC,hbrush);
         //Ellipse(hMemDC,0+200,0+200+30,100+200,100+200+30);
         Circle(hMemDC,ox,oy+0.8*r,r);
         BitBlt(hdc,,,,,hMemDC,,,SRCPAINT);
         //GREEN
         hbrush = CreateSolidBrush(RGB(, , ));
         SelectObject(hMemDC,hbrush);
         //Ellipse(hMemDC,0+200-26,0+200-15,100+200-26,100+200-15);
         Circle(hMemDC,ox-0.866*0.8*r,oy-0.5*0.8*r,r);
         BitBlt(hdc,,,,,hMemDC,,,SRCPAINT);
         //BLUE
         hbrush = CreateSolidBrush(RGB(, , ));
         SelectObject(hMemDC,hbrush);
         //Ellipse(hMemDC,0+200+26,0+200-15,100+200+26,100+200-15);
         Circle(hMemDC,ox+0.866*0.8*r,oy-0.5*0.8*r,r);
         BitBlt(hdc,,,,,hMemDC,,,SRCPAINT);
         //
         DeleteObject(hBitmap);
         DeleteDC( hMemDC );
         EndPaint (hWnd, &ps) ;

         break;
     case WM_DESTROY :
         PostQuitMessage();
         break ;
     }
     return DefWindowProc (hWnd, message, wParam, lParam) ;
 }