LoadBitmap image not shown problem

This is a discussion on LoadBitmap image not shown problem within the Windows Programming forums, part of the Platform Specific Boards category; Hi guys, can you shed some light on my problem? I'm try to study (again) win32 programming and i want ...

  1. #1
    Registered User
    Join Date
    Dec 2005
    Posts
    50

    Question LoadBitmap image not shown problem

    Hi guys,

    can you shed some light on my problem?

    I'm try to study (again) win32 programming and i want to do is to show a bitmap image. i'm using LoadBitmap and it compiles but when i run no image is shown.

    i've created the necessary resource file and when debug mode it shows that there is an object created, but there is no image...

    here is the code:
    Code:
    // internet_detector.cpp : Defines the entry point for the application.
    //
    
    #include "stdafx.h"
    
    #define MAX_LOADSTRING 100
    
    // Global Variables:
    HINSTANCE hInst;								// current instance
    TCHAR szTitle[MAX_LOADSTRING];					// The title bar text
    TCHAR szWindowClass[MAX_LOADSTRING];			// the main window class name
    
    //PICTURE!
    HBITMAP g_hbmBall = NULL;
    
    // Forward declarations of functions included in this code module:
    ATOM				MyRegisterClass(HINSTANCE hInstance);
    BOOL				InitInstance(HINSTANCE, int);
    LRESULT CALLBACK	WndProc(HWND, UINT, WPARAM, LPARAM);
    INT_PTR CALLBACK	About(HWND, UINT, WPARAM, LPARAM);
    
    int APIENTRY _tWinMain(HINSTANCE hInstance,
                         HINSTANCE hPrevInstance,
                         LPTSTR    lpCmdLine,
                         int       nCmdShow)
    {
    	UNREFERENCED_PARAMETER(hPrevInstance);
    	UNREFERENCED_PARAMETER(lpCmdLine);
    
     	// TODO: Place code here.
    	MSG msg;
    	HACCEL hAccelTable;
    
    	// Initialize global strings
    	LoadString(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING);
    	LoadString(hInstance, IDC_INTERNET_DETECTOR, szWindowClass, MAX_LOADSTRING);
    	MyRegisterClass(hInstance);
    
    	// Perform application initialization:
    	if (!InitInstance (hInstance, nCmdShow))
    	{
    		return FALSE;
    	}
    
    	hAccelTable = LoadAccelerators(hInstance, MAKEINTRESOURCE(IDC_INTERNET_DETECTOR));
    
    	// Main message loop:
    	while (GetMessage(&msg, NULL, 0, 0))
    	{
    		if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg))
    		{
    			TranslateMessage(&msg);
    			DispatchMessage(&msg);
    		}
    	}
    
    	return (int) msg.wParam;
    }
    
    
    
    //
    //  FUNCTION: MyRegisterClass()
    //
    //  PURPOSE: Registers the window class.
    //
    //  COMMENTS:
    //
    //    This function and its usage are only necessary if you want this code
    //    to be compatible with Win32 systems prior to the 'RegisterClassEx'
    //    function that was added to Windows 95. It is important to call this function
    //    so that the application will get 'well formed' small icons associated
    //    with it.
    //
    ATOM MyRegisterClass(HINSTANCE hInstance)
    {
    	WNDCLASSEX wcex;
    
    	wcex.cbSize = sizeof(WNDCLASSEX);
    
    	wcex.style			= CS_HREDRAW | CS_VREDRAW;
    	wcex.lpfnWndProc	= WndProc;
    	wcex.cbClsExtra		= 0;
    	wcex.cbWndExtra		= 0;
    	wcex.hInstance		= hInstance;
    	wcex.hIcon			= LoadIcon(hInstance, MAKEINTRESOURCE(IDI_INTERNET_DETECTOR));
    	wcex.hCursor		= LoadCursor(NULL, IDC_ARROW);
    	wcex.hbrBackground	= (HBRUSH)(COLOR_WINDOW+1);
    	wcex.lpszMenuName	= MAKEINTRESOURCE(IDC_INTERNET_DETECTOR);
    	wcex.lpszClassName	= szWindowClass;
    	wcex.hIconSm		= LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_SMALL));
    
    	return RegisterClassEx(&wcex);
    }
    
    //
    //   FUNCTION: InitInstance(HINSTANCE, int)
    //
    //   PURPOSE: Saves instance handle and creates main window
    //
    //   COMMENTS:
    //
    //        In this function, we save the instance handle in a global variable and
    //        create and display the main program window.
    //
    BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
    {
       HWND hWnd;
    
       hInst = hInstance; // Store instance handle in our global variable
    
       hWnd = CreateWindow(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
          CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);
    
       if (!hWnd)
       {
          return FALSE;
       }
    
       ShowWindow(hWnd, nCmdShow);
       UpdateWindow(hWnd);
    
       return TRUE;
    }
    
    //
    //  FUNCTION: WndProc(HWND, UINT, WPARAM, LPARAM)
    //
    //  PURPOSE:  Processes messages for the main window.
    //
    //  WM_COMMAND	- process the application menu
    //  WM_PAINT	- Paint the main window
    //  WM_DESTROY	- post a quit message and return
    //
    //
    LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
    {
    	int wmId, wmEvent;
    	PAINTSTRUCT ps;
    	HDC hdc;
    
    	HWND hWndEdit;
    
    	switch (message)
    	{
    
    	case WM_COMMAND:
    		wmId    = LOWORD(wParam);
    		wmEvent = HIWORD(wParam);
    		// Parse the menu selections:
    		switch (wmId)
    		{
    		case IDM_ABOUT:
    			DialogBox(hInst, MAKEINTRESOURCE(IDD_ABOUTBOX), hWnd, About);
    			break;
    		case IDM_EXIT:
    			DestroyWindow(hWnd);
    			break;
    		default:
    			return DefWindowProc(hWnd, message, wParam, lParam);
    		}
    		break;
    	case WM_PAINT:
    		{
    			BITMAP bm;
    			hdc = BeginPaint(hWnd, &ps);
    			HDC hdc = BeginPaint(hWnd, &ps);
    
    			HDC hdcMem = CreateCompatibleDC(hdc);
    			HBITMAP hbmOld = (HBITMAP)SelectObject(hdcMem, g_hbmBall);
    
    			GetObject(g_hbmBall, sizeof(bm), &bm);
    			BitBlt(hdc, 0, 0, bm.bmWidth, bm.bmHeight, hdcMem, 0, 0, SRCCOPY);
    			SelectObject(hdcMem, hbmOld);
    			DeleteDC(hdcMem);
    
    			EndPaint(hWnd, &ps);
    		}
    		break;
    
    	case WM_DESTROY:
    		DeleteObject(g_hbmBall);
    		PostQuitMessage(0);
    		break;
    
    	//ADDITIONAL CASES:
    
    	case WM_CREATE:
    	{
    		
    		//image
    		g_hbmBall = LoadBitmap(GetModuleHandle(NULL), MAKEINTRESOURCE( IDB_RED ));
    
    		if(g_hbmBall == NULL)
    		MessageBox(hWnd,  TEXT("Could not load IDB_BALL!"), TEXT ("Error"), MB_OK |
    		MB_ICONEXCLAMATION);
    
    		//text
    		hWndEdit = CreateWindow(TEXT("Edit"), TEXT("Hello World"),
    		WS_BORDER | WS_CHILD | WS_VISIBLE,
    		100, 20, 140, 20, hWnd, NULL, NULL, NULL);
    
    	}
    	break;
    
    	default:
    		return DefWindowProc(hWnd, message, wParam, lParam);
    	}
    	return 0;
    }
    
    // Message handler for about box.
    INT_PTR CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
    {
    	UNREFERENCED_PARAMETER(lParam);
    	switch (message)
    	{
    	case WM_INITDIALOG:
    		return (INT_PTR)TRUE;
    
    	case WM_COMMAND:
    		if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL)
    		{
    			EndDialog(hDlg, LOWORD(wParam));
    			return (INT_PTR)TRUE;
    		}
    		break;
    	}
    	return (INT_PTR)FALSE;
    }
    i'm using visual c++ 2008 express edition to compile.

  2. #2
    Kernel hacker
    Join Date
    Jul 2007
    Location
    Farncombe, Surrey, England
    Posts
    15,677
    Which hdc did you intend on using, and are both valid?
    Code:
    			hdc = BeginPaint(hWnd, &ps);
    			HDC hdc = BeginPaint(hWnd, &ps);
    I don't know very much about about WinAPI, but
    Quote Originally Posted by MSDN
    Each call to BeginPaint must have a corresponding call to the EndPaint function.
    --
    Mats
    Compilers can produce warnings - make the compiler programmers happy: Use them!
    Please don't PM me for help - and no, I don't do help over instant messengers.

  3. #3
    Registered User Codeplug's Avatar
    Join Date
    Mar 2003
    Posts
    4,645
    I see this after a quick glance:
    Code:
            hdc = BeginPaint(hWnd, &ps);
            HDC hdc = BeginPaint(hWnd, &ps);
    You should call BeginPain() only once.....which you probably know

    [edit]I'm the slower poster [/edit]
    gg

  4. #4
    Registered User
    Join Date
    Dec 2005
    Posts
    50
    awww... my bad...

    that solves the problem completely...

    thank you!!!

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