clip.cpp

WINDOWS2000开发人员指南源代码第五章的

// transblt.cpp : Defines the entry point for the application.
//

#include "stdafx.h"
#include "resource.h"

#define MAX_LOADSTRING 100

// Global Variables:
HINSTANCE hInst;						// current instance
TCHAR szTitle[MAX_LOADSTRING];			// The title bar text
TCHAR szWindowClass[MAX_LOADSTRING];	// The title bar text

// Foward declarations of functions included in this code module:
ATOM				MyRegisterClass(HINSTANCE hInstance);
BOOL				InitInstance(HINSTANCE, int);
LRESULT CALLBACK	WndProc(HWND, UINT, WPARAM, LPARAM);
void                OnPaint(HWND hWnd);
LRESULT CALLBACK	About(HWND, UINT, WPARAM, LPARAM);

//
// WinMain: Entry point for the application
//
int APIENTRY WinMain
(
    HINSTANCE hInstance
   ,HINSTANCE /*hPrevInstance*/
   ,LPSTR /*pCmdLine*/
   ,int nCmdShow
)
{
	MSG msg;
	HACCEL hAccelTable;

	// Initialize global strings
	LoadString(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING);
	LoadString(hInstance, IDC_CLIP, szWindowClass, MAX_LOADSTRING);
	MyRegisterClass(hInstance);

	// Perform application initialization:
	if (!InitInstance (hInstance, nCmdShow)) 
	{
		return FALSE;
	}

	hAccelTable = LoadAccelerators(hInstance, (LPCTSTR)IDC_CLIP);

	// Main message loop:
	while (GetMessage(&msg, NULL, 0, 0)) 
	{
		if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg)) 
		{
			TranslateMessage(&msg);
			DispatchMessage(&msg);
		}
	}

	return msg.wParam;
}

//
// MyRegisterClass: registers the window class
//
ATOM MyRegisterClass(HINSTANCE hInstance)
{
    WNDCLASSEX wcex;

    wcex.cbSize = sizeof(WNDCLASSEX); 

    wcex.style			= CS_HREDRAW | CS_VREDRAW;
    wcex.lpfnWndProc	= (WNDPROC)WndProc;
    wcex.cbClsExtra		= 0;
    wcex.cbWndExtra		= 0;
    wcex.hInstance		= hInstance;
    wcex.hIcon			= LoadIcon(hInstance, (LPCTSTR)IDI_CLIP);
    wcex.hCursor		= LoadCursor(NULL, IDC_ARROW);
    wcex.hbrBackground	= (HBRUSH)(COLOR_WINDOW+1);
    wcex.lpszMenuName	= (LPCSTR)IDC_CLIP;
    wcex.lpszClassName	= szWindowClass;
    wcex.hIconSm		= LoadIcon(wcex.hInstance, (LPCTSTR)IDI_SMALL);

    return RegisterClassEx(&wcex);
}

//
// InitInstance: creates the window
//
BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
    BOOL bReturn(FALSE);
    HWND hWnd;

    // Store instance handle in our global variable
    hInst = hInstance; 

    hWnd = CreateWindow(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);
    if (hWnd)
    {
        ShowWindow(hWnd, nCmdShow);
        UpdateWindow(hWnd);
        bReturn = TRUE;
    } 

   return bReturn;
}

//
//  WndProc: main window window procedure
//
LRESULT CALLBACK WndProc
(
    HWND hWnd
   ,UINT message
   ,WPARAM wParam
   ,LPARAM lParam
)
{
	int wmId, wmEvent;

	switch (message) 
	{
		case WM_COMMAND:
			wmId    = LOWORD(wParam); 
			wmEvent = HIWORD(wParam); 
			// Parse the menu selections:
			switch (wmId)
			{
				case IDM_ABOUT:
				   DialogBox(hInst, (LPCTSTR)IDD_ABOUTBOX, hWnd, (DLGPROC)About);
				   break;
				case IDM_EXIT:
				   DestroyWindow(hWnd);
				   break;
				default:
				   return DefWindowProc(hWnd, message, wParam, lParam);
			}
		break;
		
        case WM_PAINT:
			OnPaint(hWnd);
		break;
		
        case WM_DESTROY:
			PostQuitMessage(0);
		break;
		
        default:
			return DefWindowProc(hWnd, message, wParam, lParam);
   }

   return 0;
}

//
// OnPaint:  handles the painting for the window
//
void OnPaint(HWND hWnd)
{
    PAINTSTRUCT ps;
    HBITMAP hBitmapOld(NULL);

    HDC hDC = BeginPaint(hWnd, &ps);

    // get the client rect
    RECT rectClient;
    GetClientRect(hWnd, &rectClient);

    // load the transparent bitmap
    HBITMAP hBitmapTransparent = LoadBitmap(
        hInst, MAKEINTRESOURCE(IDB_TRANSPARENT));
 
    // get the dimension of the transparent bitmap so we can
    // center the window and create a clipping region 
    BITMAP bitmapTransparent;
    GetObject(hBitmapTransparent,
        sizeof(bitmapTransparent), &bitmapTransparent);

    int nLeft = 
        (rectClient.right / 2) - (bitmapTransparent.bmWidth / 2);
    int nTop =  
        (rectClient.bottom / 2) - (bitmapTransparent.bmHeight / 2);

    // set the clipping region to the size and position of the 
    //  transparent bitmap
    HRGN hrgnClip = CreateRectRgn(
        nLeft, nTop,
        nLeft + bitmapTransparent.bmWidth,
        nTop + bitmapTransparent.bmHeight);

    // select the clip region
    SelectClipRgn(hDC, hrgnClip);

    // delete the region
    DeleteObject(hrgnClip);

    // create a compatible memory dc
    HDC hDCMem = CreateCompatibleDC(hDC);

    //
    // draw an the background image in the middle of the screen
    //

    // load the background bitmap
    HBITMAP hBitmapBackground = LoadBitmap(
        hInst, MAKEINTRESOURCE(IDB_BACKGROUNDBITMAP));

    // select the bitamp into the memory dc
    hBitmapOld = (HBITMAP)SelectObject(
        hDCMem, hBitmapBackground);

    // get the dimension of the bitmap so we can center
    // it in the window
    BITMAP bitmapBackground;
    GetObject(hBitmapBackground,
        sizeof(bitmapBackground), &bitmapBackground);

    int nLeftBackground = 
        (rectClient.right / 2) - (bitmapBackground.bmWidth / 2);
    int nTopBackground =  
        (rectClient.bottom / 2) - (bitmapBackground.bmHeight / 2);

    // draw the background bitmap
    BitBlt(hDC, nLeftBackground, nTopBackground,
        bitmapBackground.bmWidth, bitmapBackground.bmHeight,
        hDCMem, 0, 0, SRCCOPY);

    //
    // Draw a transparent bitmap over the background bitmap
    //
    
    // select the transparentbitamp into the memory dc
    SelectObject(hDCMem, hBitmapTransparent);
    
    // draw the transparent bitmap
    TransparentBlt(hDC, nLeft, nTop, 
        bitmapTransparent.bmWidth, bitmapTransparent.bmHeight, 
        hDCMem, 0, 0,
        bitmapTransparent.bmWidth, bitmapTransparent.bmHeight,
        RGB(0,0,255));

    // Select the old bitmap
    SelectObject(hDCMem, hBitmapOld);

    DeleteObject(hBitmapBackground);
    DeleteObject(hBitmapTransparent);

    EndPaint(hWnd, &ps);
}

//
// Mesage handler for about box.
//
LRESULT CALLBACK About
(
    HWND hDlg
   ,UINT message
   ,WPARAM wParam
   ,LPARAM /*lParam*/
)
{
    switch (message)
    {
        case WM_INITDIALOG:
            return TRUE;

        case WM_COMMAND:
            if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL) 
            {
                EndDialog(hDlg, LOWORD(wParam));
                return TRUE;
            }
        break;
    }

    return FALSE;
}