Windows Programming
Lecture Notes (open in IE)Comparison between command line (dos) C++ and Windows version
// std. version
#include
//entry point
void main (void)
{
printf(:\n There can be only one!!!");
}
// Windows version
//simple message box
#define WIN32_LEAN_AND_MEAN
#include
#include
//main entry point for all windows programs
int WINAPI WinMain(HINSTANCE hinstance, HINSTANCE hprevinstance, LPSTR lpcmdline, int ncmdshow)
{
//call message box API with NULL for parent
//window handle
parent message string title
| | |
MessageBox (NULL,"There can be only one!!!", "My first windows program", MB_OK|MB_ICONEXCLAMATION); <--- style options
//exit
return(0);
} // end WinMain
Window class
everything is a window , including buttons and toolbars
WNDCLASSEX winclass; // holds the class that we create
HWND handle; // generic window handle
Msg message; // generic message
Declare windows fields
Register window class
Create windows
Display window - ShowWindow(hwnd, SW_SHOW); , UpdateWindow()
Event Handler
Processing Messages
case WM_CREATE:
{
// do initialization stuff here
return(0); //return success
} break;
case WM_PAINT:
{
// simply validate the window
hdc=BeginPaint(hwnd, &ps);
// you would do all your painting here
EndPaint(hwnd, &ps);
return(0); // return success
} break;
case WM_DESTROY:
{
// kill the application, this sends the WM_QUIT message
PostQuitMessage(0);
return(0); // return success
}break;
default: break;
} //end switch
Main Event Loop
// enter main event loop
while(GetMessage(&msg,NULL,0,0))
{
// Translate any accelerator keys
TranslateMessage(&msg);
// send the message to the window proc
DispatchMessage(&msg);
} // end while
// return to the Windows desktop like this
return (msg.wParam);
Different Main Event Loop
while(TRUE)
{
// if there is a message in the queue, get it
if(PeekMessage(&msg,NULL,0,0,PM_REMOVE)
{
// test if this is a quit
if (msg.message==WM_QUIT)
break;
//translate any accelerator keys
TranslateMessage(&msg);
// send the message to the window proc
DispatchMessage(&msg);
} // end if
} // end while
Handle the windows event messages yourself by adding sections to the switch statement in the callback (WinProc). Eg. close window, force repaint, kill application
Postmessage - send to queue for normal processing
Postmessage(hwnd, WM_USER, w, l);
Sendmessage - send message to window bypassing to queue and requiring immediate response
Sendmessage(hwnd, WM_USER, w, l);
wparam and lparam are parameters and will contain information depending on the message being sent to the window
Movable Window
case WM_MOVE:
{
// extract the position
int xpos = LOWORD (lparam);
int ypos = HIWORD (lparam);
// get a graphics context
hdc=GetDC(hwnd);
// set the foreground color to green
SetTextColor(hdc, RGB(0,255,0));
// set the background color to white
SetBkColor(hdc, RGB(255,255,255));
// set the transparency mode to Opaque
SetBkMode(hdc, OPAQUE);
// draw the size of the window
sprintf(buffer, "WM_MOVE called - New Position = (%d,%d)",xpos, ypos);
TextOut(hdc,0,0,buffer, strlen(buffer));
//release the dc back
ReleaseDC (hwnd,hdc);
} break;
Keyboard
To process the key presses, use the message WM_CHAR
wparam = ASCII character code
lparam = bit code for key state
case WM_CHAR:
{
// get the character
char ascii_code = wparam;
unsigned int key_state = lparam;
//get a graphics context
hdc=GetDC(hwnd);
//set the foreground color to cyan
SetTextColor(hdc, RGB(0.255,255));
//set the background color to black
SetBkColor(hdc,RGB(0,0,0));
//set the transparency mode to OPAQUE
SetBkMode(hdc,OPAQUE);
//print the ascii code and key state
sprintf(buffer, "WM_CHAR: Character = %c", ascii_code);
TextOut(hdc,0,0,buffer,strlen(buffer));
//release the dc back
ReleaseDC(hwnd, hdc);
}break;
You can bypass the message passing state by using GetAsynchKeyState()
case WM_KEYDOWN:
{
int virtual_code = (int) wparam;
int key_bits = (int) lparam;
switch(virtual_code)
{
case VK_RIGHT:
case VK_LEFT:
default:
} // end switch
} // end case
for WM_MOUSEMOVE, wparam - button state bits, lparam - loword is x position, hiword is y position
posted by v_tel001 @ 3:42 PM
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