win32/examples/hello_win.c

   1 //+---------------------------------------------------------------------------
   2 //
   3 //  HELLO_WIN.C - Windows GUI 'Hello World!' Example
   4 //
   5 //+---------------------------------------------------------------------------
   6
   7 #include <windows.h>
   8
   9 #define APPNAME "HELLO_WIN"
  10
  11 char szAppName[] = APPNAME; // The name of this application
  12 char szTitle[]   = APPNAME; // The title bar text
  13 const char *pWindowText;
  14
  15 void CenterWindow(HWND hWnd);
  16
  17 //+---------------------------------------------------------------------------
  18 //
  19 //  Function:   WndProc
  20 //
  21 //  Synopsis:   very unusual type of function - gets called by system to
  22 //              process windows messages.
  23 //
  24 //  Arguments:  same as always.
  25 //----------------------------------------------------------------------------
  26
  27 LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
  28 {
  29     switch (message) {
  30
  31         // ----------------------- first and last
  32         case WM_CREATE:
  33             CenterWindow(hwnd);
  34             break;
  35
  36         case WM_DESTROY:
  37             PostQuitMessage(0);
  38             break;
  39
  40         // ----------------------- get out of it...
  41         case WM_RBUTTONUP:
  42             DestroyWindow(hwnd);
  43             break;
  44
  45         case WM_KEYDOWN:
  46             if (VK_ESCAPE == wParam)
  47                 DestroyWindow(hwnd);
  48             break;
  49
  50         // ----------------------- display our minimal info
  51         case WM_PAINT:
  52         {
  53             PAINTSTRUCT ps;
  54             HDC         hdc;
  55             RECT        rc;
  56             hdc = BeginPaint(hwnd, &ps);
  57
  58             GetClientRect(hwnd, &rc);
  59             SetTextColor(hdc, RGB(240,240,96));
  60             SetBkMode(hdc, TRANSPARENT);
  61             DrawText(hdc, pWindowText, -1, &rc, DT_CENTER|DT_SINGLELINE|DT_VCENTER);
  62
  63             EndPaint(hwnd, &ps);
  64             break;
  65         }
  66
  67         // ----------------------- let windows do all other stuff
  68         default:
  69             return DefWindowProc(hwnd, message, wParam, lParam);
  70     }
  71     return 0;
  72 }
  73
  74 //+---------------------------------------------------------------------------
  75 //
  76 //  Function:   WinMain
  77 //
  78 //  Synopsis:   standard entrypoint for GUI Win32 apps
  79 //
  80 //----------------------------------------------------------------------------
  81 int APIENTRY WinMain(
  82         HINSTANCE hInstance,
  83         HINSTANCE hPrevInstance,
  84         LPSTR lpCmdLine,
  85         int nCmdShow
  86         )
  87 {
  88     MSG msg;
  89     WNDCLASS wc;
  90     HWND hwnd;
  91
  92     pWindowText = lpCmdLine[0] ? lpCmdLine : "Hello Windows!";
  93
  94     // Fill in window class structure with parameters that describe
  95     // the main window.
  96
  97     ZeroMemory(&wc, sizeof wc);
  98     wc.hInstance     = hInstance;
  99     wc.lpszClassName = szAppName;
 100     wc.lpfnWndProc   = (WNDPROC)WndProc;
 101     wc.style         = CS_DBLCLKS|CS_VREDRAW|CS_HREDRAW;
 102     wc.hbrBackground = (HBRUSH)GetStockObject(BLACK_BRUSH);
 103     wc.hIcon         = LoadIcon(NULL, IDI_APPLICATION);
 104     wc.hCursor       = LoadCursor(NULL, IDC_ARROW);
 105
 106     if (FALSE == RegisterClass(&wc))
 107         return 0;
 108
 109     // create the browser
 110     hwnd = CreateWindow(
 111         szAppName,
 112         szTitle,
 113         WS_OVERLAPPEDWINDOW|WS_VISIBLE,
 114         CW_USEDEFAULT,
 115         CW_USEDEFAULT,
 116         360,//CW_USEDEFAULT,
 117         240,//CW_USEDEFAULT,
 118         0,
 119         0,
 120         hInstance,
 121         0);
 122
 123     if (NULL == hwnd)
 124         return 0;
 125
 126     // Main message loop:
 127     while (GetMessage(&msg, NULL, 0, 0) > 0) {
 128         TranslateMessage(&msg);
 129         DispatchMessage(&msg);
 130     }
 131
 132     return msg.wParam;
 133 }
 134
 135 //+---------------------------------------------------------------------------
 136
 137 //+---------------------------------------------------------------------------
 138
 139 void CenterWindow(HWND hwnd_self)
 140 {
 141     HWND hwnd_parent;
 142     RECT rw_self, rc_parent, rw_parent;
 143     int xpos, ypos;
 144
 145     hwnd_parent = GetParent(hwnd_self);
 146     if (NULL == hwnd_parent)
 147         hwnd_parent = GetDesktopWindow();
 148
 149     GetWindowRect(hwnd_parent, &rw_parent);
 150     GetClientRect(hwnd_parent, &rc_parent);
 151     GetWindowRect(hwnd_self, &rw_self);
 152
 153     xpos = rw_parent.left + (rc_parent.right + rw_self.left - rw_self.right) / 2;
 154     ypos = rw_parent.top + (rc_parent.bottom + rw_self.top - rw_self.bottom) / 2;
 155
 156     SetWindowPos(
 157         hwnd_self, NULL,
 158         xpos, ypos, 0, 0,
 159         SWP_NOSIZE|SWP_NOZORDER|SWP_NOACTIVATE
 160         );
 161 }
 162
 163 //+---------------------------------------------------------------------------