Releasing memory allocated with Image.load method in MFC - mfc

Question

In MFC I'm loading a .PNG image and thereafter, I'm displaying it with a static control as below:
CImage Img;
Img.Load(_T(abc.png"));
CBitMap Bmp;
Bmp.Attach(Img.Detach());
CStatic dispImg;
dispImg.SetBitmap(Bmp);
In this way I've several images which I'm displaying with the static control repetitively
which is causing significant memory leak within my application. I found several clues by googling, but I couldn't decide the best option for releasing memory. Could anybody please guide me with the best approach.

Answer 1

This code is incomplete. Using a CStatic in this way will never work. It isn't created.
If you realy want help that macthes your question give a more detailed description.
When you use CStatic::SetBitmap ypu must free the HBITMAP handle that is returned by the function. Just read the docs. So if you use this samne CStatic in a Loop and always assign a new Bitmap to the CStatic this may cause a leak.

Answer 2

As xMRi suggested I'm freeing HBITMAP handle returned by CStatic::SetBitmap. In my test app there is a CStatic control member m_pic, a method ChangePic which sets a Bitmap and a button control for changing the image based on a value of a boolean variable SetBlueImg. Defination of ChangePic as below:
void CPNGTestDlg::ChangePic(Cstring img)
{
CImage Img;
Img.Load(img);
CBitmap Bmp;
Bmp.Attach(Img.Detach());
HBITMAP hBmp=m_pic.SEtBitmap(Bmp);
if(hBmp!=NULL) DeleteObject(hBmp);
}
Click event of the button is defined as below:
void CPNGTest::OnBnClickedChngPic()
{
if(SetBlueImg)
{
ChangePic(_T("Blue.png"));
SetBlueImg=false;
}
else
{
ChangePic(_T("Red.png"));
SetBlueImg=true;
}
}
Initial value of SetBlueImg=true and in OnInitDialog() I called ChangePic(_T("Red.png"));
I ran the application and continuously clicking the button to change current image but still I can see memory leaks through windows task manager. Hike of memory is by 4KB after clicking button 40/50 times or sometimes unpredictably. Please, point out where I'm missing something which is causing the leaks.

Answer 3

To get rid of overlapped images when replacing one image on a Static Control with another one, I initially followed the steps below:
ShowWindow(SW_HIDE)
SetBitmap()
ShowWindow(SW_SHOW)
but I didn't know whether this is a correct way to solve the image overlapping. I searched a bit by googling and found the following way:
Copying area on the parent window behind the static control before it is drawn for the first time.
Copying the image back to the parent every time the static control needs to be redrawn.

Answer 4

The HBITMAP object has to be deleted when the dialog is destroyed.
void CMFCAppDlg::OnDestroy()
{
CDialogEx::OnDestroy();
DeleteObject(m_pic.GetBitmap());
}