^A Paint Program in Visual C++^

				
//**************************************
// Name: ^A Paint Program in Visual C++^
// Description:This shows how to make a simple free-hand drawing program in Visual C++. The code is commented.
// By: Niloy Mondal
//
//This code is copyrighted and has// limited warranties.Please see http://www.Planet-Source-Code.com/vb/scripts/ShowCode.asp?txtCodeId=4600&lngWId=3//for details.//**************************************

//Programmer:- Niloy Mondal. Email:- niloygk@yahoo.com
#include <windows.h>
LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;
int lastx,lasty,x,y;		//GLOBAL VARIABLES used in drawing.
//The WinMain contains all formality stuff that must be written in almost every Windows Program.
int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
 PSTR szCmdLine, int iCmdShow)
{
static TCHAR szAppName[] = TEXT ("Paint") ;//Winddow Class name
HWND hwnd ;
MSG msg ;
WNDCLASSwndclass ;
wndclass.style = CS_HREDRAW | CS_VREDRAW ;
wndclass.lpfnWndProc = WndProc ;
wndclass.cbClsExtra = 0 ;
wndclass.cbWndExtra = 0 ;
wndclass.hInstance= hInstance ;
wndclass.hIcon = LoadIcon (NULL, IDI_APPLICATION) ;
wndclass.hCursor= LoadCursor (NULL, IDC_ARROW) ;
wndclass.hbrBackground = (HBRUSH) GetStockObject (WHITE_BRUSH) ;
wndclass.lpszMenuName = NULL ;
wndclass.lpszClassName = szAppName ;
if (!RegisterClass (&wndclass))
{
 MessageBox (NULL, TEXT ("This program requires Windows 98!"), 
szAppName, MB_ICONERROR) ;
 return 0 ;
}
hwnd = CreateWindow (szAppName, // window class name
 TEXT ("Paint in Visual C++."), // window caption
 WS_OVERLAPPEDWINDOW,// window style
 CW_USEDEFAULT,// initial x position
 CW_USEDEFAULT,// initial y position
 CW_USEDEFAULT,// initial x size
 CW_USEDEFAULT,// initial y size
 NULL,// parent window handle
 NULL,// window menu handle
 hInstance, // program instance handle
 NULL) ;// creation parameters
ShowWindow (hwnd, iCmdShow) ;
UpdateWindow (hwnd) ;
while (GetMessage (&msg, NULL, 0, 0))				//The Message Loop
{
 TranslateMessage (&msg) ;
 DispatchMessage (&msg) ;
}
return msg.wParam ;
}
void line(HDC _hdc,int x1,int y1,int x2,int y2)//This function draws line by the given four coordinates.
{
	MoveToEx(_hdc,x1,y1,NULL);
	LineTo(_hdc,x2,y2);
}
LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
HDC hdc ;
PAINTSTRUCT ps ;
RECTrect ;
	 	
switch (message)
{
	 case WM_LBUTTONDOWN:					//If Left mouse button is pressed
			lastx=LOWORD(lParam);			//Store the x-coordiante in lastx
			lasty=HIWORD(lParam);			//Store the y-coordinate in lasty
			return 0;
case WM_MOUSEMOVE:						//When mouse is moved on the client area (or form for VB users)
		 hdc = GetDC(hwnd);					//hdc is handle to device context
		 x=LOWORD(lParam);					//Store the current x 
		 y=HIWORD(lParam);					//Store the current y
		 if (wParam & MK_LBUTTON)			//If Left mouse button is down then draw
		 {	
			line(hdc,lastx,lasty,x,y);		//Draw the line frome the last pair of coordiates to current
			lastx=x;						//The current x becomes the lastx for next line to be drawn
			lasty=y;						//The current y becomes the lasty for next line to be drawn
		 }
		 ReleaseDC(hwnd,hdc);
		 return 0;
case WM_PAINT:
 hdc = BeginPaint (hwnd, &ps) ;
 GetClientRect (hwnd, &rect) ;
		 TextOut(hdc,0,0 ,"Programmer :- Niloy Mondal. Email:- niloygk@yahoo.com",53);		 		 		 
		 EndPaint (hwnd, &ps) ;
 return 0 ;
 
case WM_DESTROY:
 PostQuitMessage (0) ;
 return 0 ;
}
return DefWindowProc (hwnd, message, wParam, lParam) ;
}