Moving Bitmaps

I've got a bitmap and when you use the up and sown arrow keys the image moves up and down the screen. It moves down ok, but there seems to be a problem with moving up the screen where part of the image make a mark up the screen.

main.cpp

Code:

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#include <windows.h>
#include <string.h>
#include <stdio.h>

/*  Declare Windows procedure  */
LRESULT CALLBACK WindowProcedure (HWND, UINT, WPARAM, LPARAM);

/*  Make the class name into a global variable  */
char szClassName[ ] = "WindowsApp";
HBITMAP Bitmap;
HINSTANCE hInst;

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

{
    HWND hwnd;              /* This is the handle for our window */
    MSG messages;            /* Here messages to the application are saved */
    WNDCLASSEX wincl;        /* Data structure for the windowclass */

    /* The Window structure */
    wincl.hInstance = hThisInstance;
    wincl.lpszClassName = szClassName;
    wincl.lpfnWndProc = WindowProcedure;      /* This function is called by windows */
    wincl.style = CS_DBLCLKS;                /* Catch double-clicks */
    wincl.cbSize = sizeof (WNDCLASSEX);

    /* Use default icon and mouse-pointer */
    wincl.hIcon = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hCursor = LoadCursor (NULL, IDC_ARROW);
    wincl.lpszMenuName = NULL;                /* No menu */
    wincl.cbClsExtra = 0;                      /* No extra bytes after the window class */
    wincl.cbWndExtra = 0;                      /* structure or the window instance */
    /* Use Windows's default color as the background of the window */
    wincl.hbrBackground = (HBRUSH) GetStockObject (COLOR_WINDOW+1);

    /* Register the window class, and if it fails quit the program */
    if (!RegisterClassEx (&wincl))
        return 0;
       
    hInst = hThisInstance;

    /* The class is registered, let's create the program*/
    hwnd = CreateWindowEx (
          0,                  /* Extended possibilites for variation */
          szClassName,        /* Classname */
          "Windows App",      /* Title Text */
          WS_OVERLAPPEDWINDOW, /* default window */
          CW_USEDEFAULT,      /* Windows decides the position */
          CW_USEDEFAULT,      /* where the window ends up on the screen */
          544,                /* The programs width */
          375,                /* 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 */
          );

    /* Make the window visible on the screen */
    ShowWindow (hwnd, nFunsterStil);

    /* Run the message loop. It will run until GetMessage() returns 0 */
    while (GetMessage (&messages, NULL, 0, 0))
    {
        /* Translate virtual-key messages into character messages */
        TranslateMessage(&messages);
        /* Send message to WindowProcedure */
        DispatchMessage(&messages);
    }

    /* The program return-value is 0 - The value that PostQuitMessage() gave */
    return messages.wParam;
}


/*  This function is called by the Windows function DispatchMessage()  */



int CharacterX = 10;
int CharacterY = 110;
int CharacterXWidth = 27;
int CharacterYWidth = 27;



void charactermove (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam);
void charactermovement (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam);

LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
   
    switch (message)                  /* handle the messages */
    {
        case WM_CREATE:
            Bitmap = LoadBitmap(hInst, "Bitmap");
            break;
        case WM_LBUTTONDOWN:
            charactermove(hwnd, message, wParam, lParam);
            break;
       
        case WM_KEYDOWN:
           
           
                 
           
            if (GetAsyncKeyState( VK_DOWN ))
            {
               
                  DeleteObject(Bitmap);
                  CharacterY++;
                 
                 
                 
                 
                  charactermove (hwnd, message, wParam, lParam);
                  return 0;
                  }
                 
                 
            else if (GetAsyncKeyState( VK_UP ))
            {
                  DeleteObject(Bitmap);
                  CharacterY--;
                 
                 
                 
                 
                 
                 
                  charactermove (hwnd, message, wParam, lParam);
                  return 0;
                  }
                 
                 
           
           
            break;
           
        case WM_DESTROY:
            DeleteObject(Bitmap);
            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;
}

void charactermove (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    HDC DC, memDC;
   
    DeleteObject(Bitmap);
    Rectangle(DC, 0, 0, 1000, 1000);
    Bitmap = LoadBitmap(hInst, "Bitmap");
   
   
                         
                   
             
   
   
    DC = GetDC(hwnd);
            memDC = CreateCompatibleDC(DC);
            SelectObject(memDC, Bitmap);
            BitBlt(DC, CharacterX, CharacterY, CharacterXWidth, CharacterYWidth, memDC, 0, 0, SRCCOPY);
            ReleaseDC(hwnd, DC);
            DeleteDC(memDC);
            }

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images.rc

Code:

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#include <windows.h>

Bitmap BITMAP img.bmp

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Does anybody know how to get rid of this

You have to erase the image before you redraw it. You can draw a filled rectangle over it that is the same color as the background. You can also make a call to InvalidateRect(NULL, TRUE); The TRUE is for erasing the screen. The NULL means that it should clear the whole window. This will send a call to WM_PAINT. This means that you don't have to delete the bitmap and reload it. You can just redraw it at the new position. You may want to keep track of the time so that you can control how fast the bitmap moves. This means that you can use WM_TIMER. If the arrow is pressed down then you use InvalidateRect. I hope this helps you.

when i put invlidaterect() in it says cannot convert int to const rect

Actually you would call InvalidateRect() as InvalidateRect(hwnd, NULL, TRUE), if you wanted to erase the entire background.

Sorry about that. I forgot that you needed the HWND hwnd. You get the point though. Let me know if it works for you.