/*
  * A basic example of Win32 programmiwng in C.
  * This source code is in the PUBLIC DOMAIN and has NO WARRANTY.
  * Colin Peters <colin@bird.fu.is.saga-u.ac.jp>
  */

#include <windows.h>
#include <string.h>

/*
  * This is the window function for the main window. Whenever a message
  * is dispatched using DispatchMessage (or sent with SendMessage) this 
  * function gets called with the contents of the message.
  */
LRESULT CALLBACK
MainWndProc (HWND hwnd, UINT nMsg, WPARAM wParam, LPARAM lParam)
{
/* The window handle for the "Click Me" button. */
static HWND hwndButton = 0;
static int cx, cy;/* Height and width of our button. */

HDC hdc;/* A device context used for drawing */
PAINTSTRUCT ps;/* Also used during window drawing */
RECT rc;/* A rectangle used during drawing */
/*
  * Perform processing based on what kind of message we got.
  */
switch (nMsg)
{
case WM_CREATE:
{
/* The window is being created. Create our button
  * window now. */
TEXTMETRIC tm;

/* First we use the system fixed font size to choose
  * a nice button size. */
hdc = GetDC (hwnd);
SelectObject (hdc, GetStockObject (SYSTEM_FIXED_FONT));
GetTextMetrics (hdc, &tm);
cx = tm.tmAveCharWidth * 30;
cy = (tm.tmHeight + tm.tmExternalLeading) * 2;
ReleaseDC (hwnd, hdc);

/* Now create the button */
hwndButton = CreateWindow (
"button",/* Builtin button class */
"Click me.",
WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON,
0, 0, cx, cy,
hwnd,/* Parent is this window. */
(HMENU) 1,/* Control ID: 1 */
((LPCREATESTRUCT) lParam)->hInstance,
NULL
);

return 0;
break;
}

case WM_DESTROY:
/* The window is being destroyed, close the application
  * (the child button gets destroyed automatically). */
PostQuitMessage (0);
return 0;
break;

case WM_PAINT:
/* The window needs to be painted (redrawn). */
hdc = BeginPaint (hwnd, &ps);
GetClientRect (hwnd, &rc);

/* Draw "Hello, World" in the middle of the upper
  * half of the window. */
rc.bottom = rc.bottom / 2;
DrawText (hdc, "Hello, World!", -1, &rc,
DT_SINGLELINE | DT_CENTER | DT_VCENTER);

EndPaint (hwnd, &ps);
return 0;
break;

case WM_SIZE:
/* The window size is changing. If the button exists
  * then place it in the center of the bottom half of
  * the window. */
if (hwndButton &&
(wParam == SIZEFULLSCREEN ||
  wParam == SIZENORMAL)
    )
{
rc.left = (LOWORD(lParam) - cx) / 2;
rc.top = HIWORD(lParam) * 3 / 4 - cy / 2;
MoveWindow (
hwndButton,
rc.left, rc.top, cx, cy, TRUE);
}
break;

case WM_COMMAND:
/* Check the control ID, notification code and
  * control handle to see if this is a button click
  * message from our child button. */
if (LOWORD(wParam) == 1 &&
     HIWORD(wParam) == BN_CLICKED &&
     (HWND) lParam == hwndButton)
{
/* Our button was clicked. Close the window. */
DestroyWindow (hwnd);
}
return 0;
break;
}

/* If we don't handle a message completely we hand it to the system
  * provided default window function. */
return DefWindowProc (hwnd, nMsg, wParam, lParam);
}


int STDCALL
WinMain (HINSTANCE hInst, HINSTANCE hPrev, LPSTR lpCmd, int nShow)
{
HWND hwndMain;/* Handle for the main window. */
MSG msg;/* A Win32 message structure. */
WNDCLASSEX wndclass;/* A window class structure. */
char*szMainWndClass = "WinTestWin";
/* The name of the main window class */

/*
  * First we create a window class for our main window.
  */

/* Initialize the entire structure to zero. */
memset (&wndclass, 0, sizeof(WNDCLASSEX));

/* This class is called WinTestWin */
wndclass.lpszClassName = szMainWndClass;

/* cbSize gives the size of the structure for extensibility. */
wndclass.cbSize = sizeof(WNDCLASSEX);

/* All windows of this class redraw when resized. */
wndclass.style = CS_HREDRAW | CS_VREDRAW;

/* All windows of this class use the MainWndProc window function. */
wndclass.lpfnWndProc = MainWndProc;

/* This class is used with the current program instance. */
wndclass.hInstance = hInst;

/* Use standard application icon and arrow cursor provided by the OS */
wndclass.hIcon = LoadIcon (NULL, IDI_APPLICATION);
wndclass.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
wndclass.hCursor = LoadCursor (NULL, IDC_ARROW);

/* Color the background white */
wndclass.hbrBackground = (HBRUSH) GetStockObject (WHITE_BRUSH);

/*
  * Now register the window class for use.
  */
RegisterClassEx (&wndclass);

/*
  * Create our main window using that window class.
  */
hwndMain = CreateWindow (
szMainWndClass,/* Class name */
"This is a test",/* Caption */
WS_OVERLAPPEDWINDOW,/* Style */
CW_USEDEFAULT,/* Initial x (use default) */
CW_USEDEFAULT,/* Initial y (use default) */
CW_USEDEFAULT,/* Initial x size (use default) */
CW_USEDEFAULT,/* Initial y size (use default) */
NULL,/* No parent window */
NULL,/* No menu */
hInst,/* This program instance */
NULL/* Creation parameters */
);

/*
  * Display the window which we just created (using the nShow
  * passed by the OS, which allows for start minimized and that
  * sort of thing).
  */
ShowWindow (hwndMain, nShow);
UpdateWindow (hwndMain);

/*
  * The main message loop. All messages being sent to the windows
  * of the application (or at least the primary thread) are retrieved
  * by the GetMessage call, then translated (mainly for keyboard
  * messages) and dispatched to the appropriate window procedure.
  * This is the simplest kind of message loop. More complex loops
  * are required for idle processing or handling modeless dialog
  * boxes. When one of the windows calls PostQuitMessage GetMessage
  * will return zero and the wParam of the message will be filled
  * with the argument to PostQuitMessage. The loop will end and
  * the application will close.
          */
while (GetMessage (&msg, NULL, 0, 0))
{
TranslateMessage (&msg);
DispatchMessage (&msg);
}
return msg.wParam;
}