1. Window

2. Data types

3. Hungarian notation Window API uses hungarian notation.
Name has a suffix showing datat type
p – pointer
lp – long pointer
...

4. LPVOID – pointer to unknown type „void *“
„LPVOID reserved“ – allways pass NULL
Independent from platform data types:
QWORD – unsigned 64 bits long (qw)
DWORD - unsigned 32 bits long (dw)
WORD - unsigned 16 bits long (w)
BYTE - unsigned 8 bits long (b)
Other types:
LONG – long (l)
UINT – unsigned integer (ui)
CHAR – character (c)
STR – zero terminated string (sz)
LPSTR – pointer to string (lpsz)

5. CHAR, CCHAR, TCHAR, WCHAR... what?
Legacy
UTF-16
CHAR, CCHAR - ANSI character
TCHAR – char to describe ANSI, DBCS or UTF-16 chars
WCHAR – UTF-16 char
UCHAR – unsigned char
„This text is written in ANSI“
L„This text is written in UNICODE“

6. HANDLES All objects Windows is responsible for are stored in a table
Every object has an identificator – HANDLE
HANDLES are unsigned 32 bits value
For interoperability on 64 bits hardware handles uses lower 32 bits
Beware some new handles (e.g. HTREEITEM)

7. HACCEL – handle to accelerator table
HBITMAP – handle to bitmap
HBRUSH – handle to brush
HDC – handle to device context
HFILE – handle to file
HWND – handle to window
HINSTANCE – handle to instance (program)
HMENU – handle to menu
HPEN – handle to pen
etc.

8. Window

9. WinMain main() is gone! What a relief it‘s still there... WinMain
wWinMain

10. Parametrai hThisInstance – ID of this program
hPrevInstance – ID of the earlier instance of this program (16-bit). For NT systems it is allways NULL
lpszArgument – command-line arguments as Unicode string
nCmdShow – a flag that says whether the main application window will be minimized, maximized or shown normally.

11. How to get a window?
Register class
Create window
Run message loop

12. Notice
Every graphical part in Windows is window, meaning window class should have many options!!!

13. WNDCLASS(EX) Window as new class Structure to define window
lpszClassName = „MyClass“
Structure to define window
Registration

14. WNDCLASS[EX] structure

15. cbSize - The size, in bytes, of this structure
cbSize - The size, in bytes, of this structure. Set this member to sizeof(WNDCLASSEX). Style - The class style(s). lpfnWndProc - A pointer to the window procedure. cbClsExtra - The number of extra bytes to allocate following the window-class structure. Default is zero. cbWndExtra - The number of extra bytes to allocate following the window instance. Default is zero. hInstance - A handle to the instance that contains the window procedure for the class. hIcon - A handle to the class icon (from resource). If NULL, default icon. hCursor - A handle to the class cursor (from resource). If NULL, default mouse cursor. hbrBackground - A handle to the class background brush. If NULL, default behaviour. lpszMenuName – A Pointer to a string that specifies the resource name (or use MAKEINTRESOURCE for integer id). NULL - no menu. lpszClassName - Specifies the window class name. hIconSm - A handle to a small icon (from resource). If NULL, default behaviour

16. Registering class RegisterClass RegisterClassA (ANSI characters)
RegisterClassW (UNICODE characters)
RegisterClassEx
RegisterClassExA (ANSI characters)
RegisterClassExW (UNICODE characters)

17. Creating window CreateWindow CreateWindowA CreateWindowW
CreateWindowEx
CreateWindowExA
CreateWindowExW
ShowWindow

19. Window styles Describes behaviour of window
Unmodifiable after window has been created
Few exceptions exists
Can be combined trough “|”
Some are incompatible
Some are already combinations
A lot of styles exists

20. Examples WS_BORDER 0x00800000L window has a thin-line border
WS_CAPTION
0x00C00000L
window has a title bar (includes the WS_BORDER)
WS_CHILD
0x L
window is a child window (cannot be used with WS_POPUP)
WS_DISABLED
0x L
window is initially disabled (EnableWindow function)
WS_POPUP
0x L
windows is a pop-up (cannot be used with WS_CHILD)
WS_VISIBLE
0x L
window is initially visible (ShowWindow or SetWindowPos function)

21. Message Loop

22. Message loop System can create a message queue for thread
Message loop must be provided
Message loop retrieves messages from thread‘s message queue and dispatches them to appropriate window procedures
System directs messages to individual windows in application
Messages has MSG data type
GetMessage() – reads message from queue or waits new one
DispatchMessage() – dispatches message to win procedure
TranslateMessage () – translates virtual-key messages into character ones and posts back to message queue

24. Windows procedure The name doesn‘t matters but prototype does:
LRESULT – multiple result (depends from message)
hwnd – handle to the window
msg – message
xPARAM – additional message information (depends from message)

25. Example WM_KEYDOWN – keyboard key is pressed down:
WPARAM will keep keys value, for example „A“
LPARAM will keep command keys values (CTRL, ALT, SHIFT and repeat function)

27. Messages
SendMessage – calls the windows procedure for the specified window and does not return until window procedure processed message
PostMessage – posts a message in message queue for specified window and returns without waiting
LRESULT WINAPI SendMessage(HWND   hWnd, UINT   Msg, WPARAM wParam, LPARAM lParam )
BOOL WINAPI PostMessage(HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam )

28. More examples WM_CREATE – create window WM_PAINT – redraw window
WM_COMMAND – user action
WM_CLOSE – this command is passed to procedure DefWindowProc, which sends WM_DESTROY message

29. Macrocommands Few macros for parameters:
WORD LOWORD(DWORD) – returns low-order word
WORD HIWORD(DWORD) – returns high-order word
BYTE LOBYTE(WORD) – returns low-order byte
BYTE HIBYTE(WORD) – returns high-order byte
Second byte from wParam - HIBYTE(LOWORD(wParam));
In 64 bits system only lower 32 bits are used

30. WPARAM, LPARAM... why? 16-bits
Parameters can be passed by WORD (16 bit) or LONG (32 bits) formats
WPARAM means 16 bits
LPARAM means 32 bits
Today both are of 32 bits long