Create a new window after pressing a button.

[Johnzzz]

Hello world!!

I am a beginner in creating windows programming. At the moment I am trying to obtain an application that displays a bmp file into a pop-up window after an action like a button or a selected menu.

The main code is here (the resource files are not relevant for the problem!):

#include <windows.h>
#include "resource.h"

LRESULT CALLBACK WindowProcedure (HWND, UINT, WPARAM, LPARAM);
LRESULT CALLBACK SplashWndProc (HWND, UINT, WPARAM, LPARAM);

HWND hMainWnd;               
HWND hSplashWnd;             
HWND hWndButton;             
HBITMAP hSplashBMP;      
HDC hSplashDC;
HDC hMemoryDC;
LONG BitmapWidth, BitmapHeight;


char szClassName[ ] = "WindowsApp";
char SplashClassName[] = "SplashWindowClass";


int WINAPI WinMain (HINSTANCE hThisInstance,
                    HINSTANCE hPrevInstance,
                    LPSTR lpszArgument,
                    int nFunsterStil)

{

    MSG messages;            
    WNDCLASSEX wincl;        
    WNDCLASSEX    splashwincl;  


    wincl.hInstance = hThisInstance;
    wincl.lpszClassName = szClassName;
    wincl.lpfnWndProc = WindowProcedure;      
    wincl.style = CS_DBLCLKS;
    wincl.cbSize = sizeof (WNDCLASSEX);
    wincl.hIcon = LoadIcon (hThisInstance, MAKEINTRESOURCE(IDI_ICON));
    wincl.hIconSm = LoadIcon (hThisInstance, MAKEINTRESOURCE(IDI_ICON));
    wincl.hCursor = LoadCursor (NULL, IDC_ARROW);
    wincl.lpszMenuName = MAKEINTRESOURCE(IDR_MENU);
    wincl.cbClsExtra = 0;                      
    wincl.cbWndExtra = 0;                      
    wincl.hbrBackground = (HBRUSH) COLOR_BACKGROUND;

    if (!RegisterClassEx (&wincl))
        return 0;

    splashwincl.cbSize           = sizeof(WNDCLASSEX);
    splashwincl.style            = 0;
    splashwincl.lpfnWndProc      = (WNDPROC)SplashWndProc;
    splashwincl.cbClsExtra       = 0;
    splashwincl.cbWndExtra       = 0;
    splashwincl.hInstance        = hThisInstance;
    splashwincl.hIcon            = NULL;
    splashwincl.hIconSm          = NULL;
    splashwincl.hCursor          = LoadCursor(NULL, IDC_ARROW);
    splashwincl.hbrBackground    = NULL;
    splashwincl.lpszMenuName     = NULL;
    splashwincl.lpszClassName    = SplashClassName;

    if (!RegisterClassEx(&splashwincl))
    {
        MessageBox(NULL, "Failed To Register The Splash Window Class.", "Error", MB_OK | MB_ICONERROR);
        return 0;
    }

    RECT DesktopRect;
    GetWindowRect(GetDesktopWindow(), &DesktopRect);    

    int mainWinRows = 256;
    int mainWinCols = 256;
    
    hMainWnd = CreateWindowEx (
           WS_EX_CLIENTEDGE,    /* Extended possibilites for variation */
           szClassName,         /* Classname */
           "Pinzas v2.0",       /* Title Text */
           WS_OVERLAPPEDWINDOW, /* default window */
           1,       /* Windows decides the position *///(DesktopRect.right - mainWinRows) / 2
           1,       /* where the window ends up on the screen *///(DesktopRect.bottom - mainWinCols) / 2
           mainWinCols,         /* The programs width */
           mainWinRows,         /* and height in pixels */
           HWND_DESKTOP,        /* The window is a child-window to desktop */
           NULL,                /* No menu */
           hThisInstance,       /* Program Instance handler */
           NULL                 /* No Window Creation data */
           );
    
    if (!hMainWnd)
    {
        MessageBox(NULL, "Window Creation Failed.", "Error", MB_OK | MB_ICONERROR);
        return 0;
    }


    hSplashBMP = LoadBitmap(hThisInstance, MAKEINTRESOURCE(BITMAP_ID));

    if (!hSplashBMP)
    {
        MessageBox(NULL, "Failed To Load Bitmap", "Error", MB_OK | MB_ICONERROR);
        return 0;
    }
    
    BITMAP Bitmap;
    GetObject(hSplashBMP, sizeof(BITMAP), &Bitmap);
    BitmapWidth = Bitmap.bmWidth;
    BitmapHeight = Bitmap.bmHeight;

    HWND hSplashWnd = CreateWindowEx(
    0,
    SplashClassName,
    "Modulator",
    WS_POPUP,
    (DesktopRect.right - BitmapWidth) / 2,
    (DesktopRect.bottom - BitmapHeight) / 2,
    Bitmap.bmWidth,
    Bitmap.bmHeight,
    HWND_DESKTOP,
    NULL,
    hThisInstance,
    NULL);
    
    if (!hSplashWnd)
    {
        MessageBox(NULL, "Splash Window Creation Failed.", "Error", MB_OK | MB_ICONERROR);
        return 0;
    }
    
    hSplashDC = GetDC(hSplashWnd);
    hMemoryDC = CreateCompatibleDC(hSplashDC);
    SelectObject(hMemoryDC, (HGDIOBJ)hSplashBMP);

    ShowWindow (hMainWnd, SW_SHOW);
    
    while (GetMessage (&messages, NULL, 0, 0))
    {
        /* Translate virtual-key messages into character messages */
        TranslateMessage(&messages);
        /* Send message to WindowProcedure */
        DispatchMessage(&messages);
    }
    
    // Free memory for the bitmap
    DeleteObject(hSplashBMP);
    ReleaseDC(hSplashWnd, hSplashDC);
    ReleaseDC(hSplashWnd, hMemoryDC);
    /* The program return-value is 0 - The value that PostQuitMessage() gave */
    return messages.wParam;
}



LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)                  /* handle the messages */
    {

        case WM_CREATE:
        {
            HINSTANCE hInstance = (HINSTANCE)GetWindowLong(hwnd, GWL_HINSTANCE);

            hWndButton = CreateWindowEx(
            0, 
            "BUTTON", 
            "Plot", 
            WS_VISIBLE | WS_CHILD, 
            10, 
            50, 
            80, 
            20, 
            hwnd, 
            (HMENU) IDB_BUTTON, 
            hInstance, 
            NULL); 
        }
        break;

        case WM_COMMAND: 
        {
            switch (LOWORD(wParam))
            {
                case IDB_BUTTON:
                {
                    switch (HIWORD(wParam))
                    {
                        case BN_CLICKED:
                            //MessageBox(NULL, "Selected Button", "Success", MB_OK | MB_ICONINFORMATION);
                            // Load the splash to the screen
                            ShowWindow (hSplashWnd, SW_SHOWNORMAL);
                        break; 
                    }
                }
                break;
                
                case IDM_FILE_EXIT: 
                    PostMessage(hwnd, WM_CLOSE, 0, 0);
                break; 

                case IDM_ITEM: 
                     ShowWindow (hSplashWnd, SW_SHOWNORMAL);
                break; 
                
            }
            return 0;
        } 
        break;
        
        case WM_DESTROY:
            PostQuitMessage (0);       /* send a WM_QUIT to the message queue */
            break;
            
        default:                      /* for messages that we don't deal with */
            return DefWindowProc (hwnd, message, wParam, lParam);
    }

    return 0;
}

LRESULT CALLBACK SplashWndProc( HWND    hwnd,
                                UINT    message,
                                WPARAM  wParam,          
                                LPARAM  lParam )
{
    HDC hdc;
    PAINTSTRUCT ps;

    switch (message)
    {
        case WM_PAINT:
             hdc = BeginPaint(hwnd, &ps);
             BitBlt(hdc, 0, 0, BitmapWidth, BitmapHeight, hMemoryDC, 0, 0, SRCCOPY); 
             EndPaint(hwnd, &ps);
        break;

        case WM_DESTROY:
        PostQuitMessage (0);       /* send a WM_QUIT to the message queue */
        break;

        default:
            return (DefWindowProc(hwnd, message, wParam, lParam));
    }
    return 0;
}

The problem is that the popup window does not appear!!. But if I include the sentence ShowWindow inside the WinMain it does appear; but what I want to do is to have the ability to control the display.

What is wrong with my code?, or is it a better way of doing this?

Thanks a lot.