Windows程序设计第五版源代码---CONNECT

源代码如下：

#include <windows.h>
#define MAXPOINTS 1000

LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM);
RECT rect;    
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow)
{
    
        
	static TCHAR szAppName[] = TEXT ("Connect");    
	HWND         hwnd;    
	MSG          msg;    
	WNDCLASS     wndclass;
   	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 Window NT!"), szAppName, MB_ICONERROR);        
    		return 0;    
    	}
    	hwnd = CreateWindow (szAppName, TEXT("Connect-the-Points Mouse Demo"),
    	                        WS_OVERLAPPEDWINDOW,                        
    	                        CW_USEDEFAULT,                        
    	                        CW_USEDEFAULT,                        
    	                        CW_USEDEFAULT,                        
    	                        CW_USEDEFAULT,                        
    	                        NULL,                        
    	                        NULL,                        
    	                        hInstance,                        
    	                        NULL
    	                     );
   	ShowWindow (hwnd, iCmdShow);    
   	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)
{
    
        
	static POINT    pt[MAXPOINTS];    
	static int      iCount;    
	HDC             hdc;    
	int             i, j;               
	PAINTSTRUCT     ps;        

	switch (message)    
	{
    
        
	case WM_LBUTTONDOWN:        
		iCount = 0;        
		InvalidateRect(hwnd, NULL, TRUE);        
		return 0;        

	case WM_MOUSEMOVE:        
		if(wParam & MK_LBUTTON && iCount < 1000)        
		{
    
                
			pt[iCount].x = LOWORD(lParam);            
			pt[iCount++].y = HIWORD(lParam);                        
			hdc = GetDC(hwnd);            
			SetPixel(hdc, LOWORD(lParam), HIWORD(lParam), 0);            
			ReleaseDC(hwnd, hdc);        
		}        
		return 0;
    	
    	case WM_LBUTTONUP:        
    		InvalidateRect(hwnd, NULL, FALSE);        
    		return 0;        

	case WM_PAINT:        
		hdc = BeginPaint(hwnd, &ps);                
		SetCursor(LoadCursor(NULL, IDC_WAIT));        
		ShowCursor(TRUE);                

		for(i = 0; i < iCount - 1; i++)            
			for(j = i + 1; j < iCount; j++)            
			{
    
                    
				MoveToEx(hdc, pt[i].x, pt[i].y, NULL);                
				LineTo(hdc, pt[j].x, pt[j].y);            
			}        
		ShowCursor(FALSE);        
		SetCursor(LoadCursor(NULL, IDC_ARROW));                

		EndPaint(hwnd, &ps);        
		return 0;        
	case WM_DESTROY:        
		PostQuitMessage(0);        
		return 0;    
	}    	
	return DefWindowProc (hwnd, message, wParam, lParam);
}

结果如图：

将鼠标指针移到客户区，按下左键，略微移动鼠标，再释放左键。按下左键快速移动鼠标，就可以得到一条经过多个点的曲线。