Create centering.c

firststeps/centering.c

@@ -0,0 +1,62 @@
+#include <windows.h>
+
+LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
+void CenterWindow(HWND);
+
+int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
+                    PWSTR pCmdLine, int nCmdShow) {
+                    
+    MSG  msg;    
+    WNDCLASSW wc = {0};
+    wc.lpszClassName = L"Center";
+    wc.hInstance     = hInstance;
+    wc.hbrBackground = GetSysColorBrush(COLOR_3DFACE);
+    wc.lpfnWndProc   = WndProc;
+    wc.hCursor       = LoadCursor(0, IDC_ARROW);
+  
+    RegisterClassW(&wc);
+    CreateWindowW(wc.lpszClassName, L"Center",
+                  WS_OVERLAPPEDWINDOW | WS_VISIBLE,
+                  100, 100, 250, 150, 0, 0, hInstance, 0);  
+
+    while (GetMessage(&msg, NULL, 0, 0)) {
+  
+        TranslateMessage(&msg);
+        DispatchMessage(&msg);
+    }
+
+    return (int) msg.wParam;
+}
+
+LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, 
+    WPARAM wParam, LPARAM lParam) {
+    
+  switch(msg) {
+  
+      case WM_CREATE: {
+      
+          CenterWindow(hwnd);
+          return 0;
+      }
+
+      case WM_DESTROY: {
+      
+          PostQuitMessage(0);
+          return 0;
+      }
+  }
+
+  return DefWindowProcW(hwnd, msg, wParam, lParam);
+}
+
+void CenterWindow(HWND hwnd) {
+
+    RECT rc;
+    
+    GetWindowRect(hwnd, &rc) ;
+    
+    SetWindowPos(hwnd, 0, 
+        (GetSystemMetrics(SM_CXSCREEN) - rc.right)/2,
+        (GetSystemMetrics(SM_CYSCREEN) - rc.bottom)/2,
+         0, 0, SWP_NOZORDER|SWP_NOSIZE);
+}