Chapter 1: Hello, MFC Windows Programming Model

1. Chapter 1: Hello, MFCWindows Programming Model Department of Digital Contents Sang Il Park

2. Programming Models • Procedural Programming model • Event-Driven Programming model(windows programming model)

3. Procedural Programming Model int main() { funcA(); funcB(); return 0; } { …… return; } { ….. return; } { funcC(); return; }

4. Procedural Programming Model • Starts with “Main()” function • Ends when main returns • Calls functions sequentially • Basically main function calls other functions (it determines what is called and when)

5. Event-driven Programming Model EVENT!!! Help me! Event Handling Message

6. Event-driven Programming Model int WinMain() { return 0; } Message Loop Window Procedure Message 2 Message 1 Message 3

7. Event-driven Programming Model • Begins with “WinMain()” function • Starts a massage loop in the WinMain for waiting messages • Gets messages from operating system, a user or the program. • Messages are processed by windows procedure • Ends when Quit message is given

8. Event-Driven Programming Model with more details:

9. Messages, messages and more Messages Common Windows Messages

10. A Simple Event-driven Coding Practice

11. Event-driven example • Using C++, Take an integer number as an input from the user and do as follows: • If the input is ‘1’, then print “Sejong University”, • If the input is ‘2’, then print“Digital Contents”, • If the input is ‘3’, then print “Bye~”and quit, • Take a new input and repeat.

12. Code: #include <iostream> using namespace std; int main() { int i; while(true) { cout<<"Input: "; cin>>i; switch(i) { case 1: cout<<"Sejong University"<<endl; break; case 2: cout<<"Digital Contents"<<endl; break; case 3: cout<<"Bye!"<<endl; return 0; break; default: break; } } return 0; }

13. Event-driven example • Using C++, Takes an integer number as an input from the user • If the input is ‘1’, then print “Sejong University”, • If the input is ‘2’, then print“Digital Contents”, • If the input is ‘3’, then print “Bye~”and quit, • Take a new input and repeat. Message (Event) Message (Event) Handler Windows Procedure Message Loop

14. Code: #include <iostream> using namespace std; int main() { int i; while(true) { cout<<"Input: "; cin>>i; switch(i) { case 1: cout<<"Sejong University"<<endl; break; case 2: cout<<"Digital Contents"<<endl; break; case 3: cout<<"Bye!"<<endl; return 0; break; default: break; } } return 0; } Message MessageLoop Message Handler

15. A fancier code: int main() { inti; while(true) { cout<<"Input: "; cin>>i; procedure(i); } return 0; } void procedure(intmsg) { switch(msg) { case 1: cout<<"Sejong University"<<endl; break; case 2: cout<<"Digital Contents"<<endl; break; case 3: cout<<"Bye!"<<endl; exit(0); break; default: break; } }

16. API Windows Programming(or SDK-Style)

17. Win32 ? (= Windows API) • Programming is not making everything from nothing • Programming is rather assembling existing functions and data types • Extended Functions and data types are distributed as a form of library • Ex.) 2D drawing functions (OpenCV library), 3D drawing functions (OpenGL library), Playing music functions (DirectShow library) and so on

18. Win32 ? ( = Windows API) • API (Application Programming Interface) • A library contains functions for controlling and using operating system. • Mostly C functions. • Win32 • Name of the Windows API • Collection of C functions for making windows programming (library) • Ex.) Functions for “creating new windows”, “adding a button”, “adding a new menu” and so on.

19. Begin Win32 Project • FileNewProjectWin32 Project

20. Begin Win32 Project • Application Setting

21. Begin Win32 Project • Set “Character Set ” as “Not Set ”

22. Adding “Main.cpp” #include <windows.h> LONG WINAPI WndProc (HWND, UINT, WPARAM, LPARAM); int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpszCmdLine, int nCmdShow) { WNDCLASS wc; HWND hwnd; MSG msg; wc.style = 0; wc.lpfnWndProc = (WNDPROC) WndProc; wc.cbClsExtra = 0; wc.cbWndExtra = 0; wc.hInstance = hInstance; wc.hIcon = LoadIcon (NULL, IDI_WINLOGO); wc.hCursor = LoadCursor (NULL, IDC_ARROW); wc.hbrBackground = (HBRUSH) (COLOR_WINDOW + 1); wc.lpszMenuName = NULL; wc.lpszClassName = "MyWndClass"; RegisterClass (&wc); hwnd = CreateWindow ( "MyWndClass", // WNDCLASS name "SDK Application", // Window title WS_OVERLAPPEDWINDOW, // Window style CW_USEDEFAULT, // Horizontal position CW_USEDEFAULT, // Vertical position CW_USEDEFAULT, // Initial width CW_USEDEFAULT, // Initial height HWND_DESKTOP, // Handle of parent window NULL, // Menu handle hInstance, // Application's instance handle NULL // Window-creation data ); ShowWindow (hwnd, nCmdShow); UpdateWindow (hwnd); while (GetMessage (&msg, NULL, 0, 0)) { TranslateMessage (&msg); DispatchMessage (&msg); } return msg.wParam; } LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam) { PAINTSTRUCT ps; HDC hdc; switch (message) { case WM_PAINT: hdc = BeginPaint (hwnd, &ps); Ellipse (hdc, 0, 0, 200, 100); EndPaint (hwnd, &ps); return 0; case WM_DESTROY: PostQuitMessage (0); return 0; } return DefWindowProc (hwnd, message, wParam, lParam); }

23. Compile and Run it!

24. Code looks complex, but… #include <windows.h> LONG WINAPI WndProc (HWND, UINT, WPARAM, LPARAM); int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpszCmdLine, int nCmdShow) { WNDCLASS wc; HWND hwnd; MSG msg; wc.style = 0; wc.lpfnWndProc = (WNDPROC) WndProc; wc.cbClsExtra = 0; wc.cbWndExtra = 0; wc.hInstance = hInstance; wc.hIcon = LoadIcon (NULL, IDI_WINLOGO); wc.hCursor = LoadCursor (NULL, IDC_ARROW); wc.hbrBackground = (HBRUSH) (COLOR_WINDOW + 1); wc.lpszMenuName = NULL; wc.lpszClassName = "MyWndClass"; RegisterClass (&wc); hwnd = CreateWindow ( "MyWndClass", // WNDCLASS name "SDK Application", // Window title WS_OVERLAPPEDWINDOW, // Window style CW_USEDEFAULT, // Horizontal position CW_USEDEFAULT, // Vertical position CW_USEDEFAULT, // Initial width CW_USEDEFAULT, // Initial height HWND_DESKTOP, // Handle of parent window NULL, // Menu handle hInstance, // Application's instance handle NULL // Window-creation data ); ShowWindow (hwnd, nCmdShow); UpdateWindow (hwnd); while (GetMessage (&msg, NULL, 0, 0)) { TranslateMessage (&msg); DispatchMessage (&msg); } return msg.wParam; } LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam) { PAINTSTRUCT ps; HDC hdc; switch (message) { case WM_PAINT: hdc = BeginPaint (hwnd, &ps); Ellipse (hdc, 0, 0, 200, 100); EndPaint (hwnd, &ps); return 0; case WM_DESTROY: PostQuitMessage (0); return 0; } return DefWindowProc (hwnd, message, wParam, lParam); } SAME STRUCTURE!

25. Little change in WinProc • In the switch statements of WinProc: case WM_PAINT: hdc = BeginPaint(hWnd, &ps); Ellipse (hdc, 0, 0, 200, 100); RECT rect; GetClientRect(hwnd, &rect); DrawText(hdc, "hello, Windows", -1, &rect, DT_SINGLELINE|DT_CENTER|DT_VCENTER); EndPaint(hWnd, &ps); return 0; Add this!

26. A Little more change in WinProc • In the switch statement, add more event handler: Add this case WM_LBUTTONDOWN: MessageBox(hwnd, "haha", "Test!"), MB_OK); break;

27. Result:

28. Summary: Win32 Program Structure WinMain(…)  main function { WNDCLASS …  Define a new program CreateWindows (…)  Create a window while( GetMessage (…))  Message Loop { DispatchMessage(…)  Message Handler } (Windows Procedure) }

29. Then, What is MFC ? To be continued…

30. Back in your home… • Read and try: Chapter1 – The Windows Programming modelChapter1 – Introducing MFC Chapter1 – Your First MFC Application