位图和位块传输(5)之画图程序

下面是一个很经典的程序，画图程序：可以画图，可以擦掉(来自Windows程序设计第五版)

#include<windows.h>
LRESULT CALLBACK WindowProc(
							HWND hwnd,      // handle to window
							UINT uMsg,      // message identifier
							WPARAM wParam,  // first message parameter
							LPARAM lParam   // second message parameter
							);

int WINAPI WinMain(
				   HINSTANCE hInstance,      // handle to current instance
				   HINSTANCE hPrevInstance,  // handle to previous instance
				   LPSTR lpCmdLine,          // command line
				   int nCmdShow              // show state
				   )
{
	static TCHAR szAppName[]=TEXT("leidemingzi");
	HWND hwnd;
	MSG msg;
	WNDCLASS wndclass;

	wndclass.cbClsExtra=0;
	wndclass.cbWndExtra=0;
	wndclass.hbrBackground=(HBRUSH)GetStockObject(WHITE_BRUSH);
	wndclass.hCursor=LoadCursor(NULL,IDC_ARROW);
	wndclass.hIcon=LoadIcon(NULL,IDI_ERROR);
	wndclass.hInstance=hInstance;
	wndclass.lpfnWndProc=WindowProc;
	wndclass.lpszClassName=szAppName;
	wndclass.lpszMenuName=NULL;
	wndclass.style=CS_HREDRAW|CS_VREDRAW;

	if(!RegisterClass(&wndclass))
	{
		MessageBox(NULL,TEXT("the program require the windows nt"),TEXT("tips"),MB_ICONERROR);
		return 0;
	}

	hwnd=CreateWindow(
		szAppName,  // registered class name
		TEXT("this is title"), // window name
		WS_OVERLAPPEDWINDOW,        // window style
		CW_USEDEFAULT,                // horizontal position of window
		CW_USEDEFAULT,                // vertical position of window
		CW_USEDEFAULT,           // window width
		CW_USEDEFAULT,          // window height
		NULL,      // handle to parent or owner window
		NULL,          // menu handle or child identifier
		hInstance,  // handle to application instance
		NULL		// window-creation data
		);

	ShowWindow(hwnd,nCmdShow);
	UpdateWindow(hwnd);

	while(GetMessage(&msg,NULL,0,0))
	{
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}

	return msg.wParam;
}

void GetLargestDisplayMode(int *pcxBitmap,int *pcyBitmap)
{
	DEVMODE devmode;
	int iModeNum=0;

	*pcxBitmap=*pcyBitmap=0;

	ZeroMemory(&devmode,sizeof(DEVMODE));
	devmode.dmSize=sizeof(DEVMODE);

	while(EnumDisplaySettings(NULL,iModeNum++,&devmode))
	{
		*pcxBitmap=max(*pcxBitmap,(int)devmode.dmPelsHeight);
		*pcyBitmap=max(*pcyBitmap,(int)devmode.dmPelsHeight);

	}
}

LRESULT CALLBACK WindowProc(
							HWND hwnd,      // handle to window
							UINT uMsg,      // message identifier
							WPARAM wParam,  // first message parameter
							LPARAM lParam   // second message parameter
							)
{
	static BOOL fLeftButtonDown,fRightButtonDown;
	static HBITMAP hBitmap;
	static HDC hdcMem;
	static int cxBitmap,cyBitmap,cxClient,cyClient,xMouse,yMouse;
	HDC hdc;
	PAINTSTRUCT ps;

	switch(uMsg)
	{
	case WM_CREATE:
		GetLargestDisplayMode(&cxBitmap,&cyClient);
		hdc=GetDC(hwnd);
		hBitmap=(HBITMAP)CreateCompatibleDC(hdc);
		ReleaseDC(hwnd,hdc);

		if(!hBitmap)
		{
			DeleteDC(hdcMem);
			return -1;
		}

		SelectObject(hdcMem,hBitmap);
		PatBlt(hdcMem,0,0,cxBitmap,cyBitmap,WHITENESS);

		return 0;

	case WM_SIZE:
		cxClient=LOWORD(lParam);
		cyClient=HIWORD(lParam);
		return 0;

	case WM_LBUTTONDOWN:
		if(!fRightButtonDown)
		{
			SetCapture(hwnd);
		}
		xMouse=LOWORD(lParam);
		yMouse=HIWORD(lParam);
		fLeftButtonDown=TRUE;
		return 0;

	case WM_LBUTTONUP:
		if(fLeftButtonDown)
		{
			SetCapture(NULL);

		}
		fLeftButtonDown=FALSE;
		return 0;

	case WM_RBUTTONDOWN:
		if(!fLeftButtonDown)
		{
			SetCapture(hwnd);
		}
		xMouse=LOWORD(lParam);
		yMouse=HIWORD(lParam);
		fRightButtonDown=TRUE;
		return 0;

	case WM_RBUTTONUP:
		if(fRightButtonDown)
		{
			SetCapture(NULL);
		}
		fRightButtonDown=FALSE;
		return 0;

	case WM_MOUSEMOVE:
		if(!fLeftButtonDown&&!fRightButtonDown)
		{
			return 0;
		}
		hdc=GetDC(hwnd);
		SelectObject(hdc,GetStockObject(fLeftButtonDown?BLACK_PEN:WHITE_PEN));

		SelectObject(hdcMem,GetStockObject(fLeftButtonDown?BLACK_PEN:WHITE_PEN));

		MoveToEx(hdc,xMouse,yMouse,NULL);
		MoveToEx(hdcMem,xMouse,yMouse,NULL);

		xMouse=(short)LOWORD(lParam);
		yMouse=(short)HIWORD(lParam);

		LineTo(hdc,xMouse,yMouse);
		LineTo(hdcMem,xMouse,yMouse);

		ReleaseDC(hwnd,hdc);
		return 0;


	case WM_PAINT:
		hdc=BeginPaint(hwnd,&ps);
		BitBlt(hdc,0,0,cxClient,cyClient,hdcMem,0,0,SRCCOPY);
		EndPaint(hwnd,&ps);
		return 0;

	case WM_DESTROY:
		DeleteDC(hdcMem);
		DeleteObject(hBitmap);
		PostQuitMessage(0);
		return 0;
	}

	return DefWindowProc(hwnd,uMsg,wParam,lParam);
}

不做过多的解释，自己动手敲敲，有用的。要下载Windows程序设计第五版光盘代码的朋友，可以到我的资源下载。