Question

MFC doc/view architecture, sdi (more precisely multiple top-level windows).

In my view class, I set my “playground” (i.e. logical space) with SetScrollSizes(); Then I want to limit maximum frame window size to that of view’s maximum size.

Here is what I’m doing but I think there might be better solution, please advice:

I’m implementing OnGetMinMaxInfo() in my CMainFrame. There I try to get active view’s scroll sizes, and set lpMMI->ptMaxTrackSize appropriately. Below is the code:

void CMainFrame::OnGetMinMaxInfo(MINMAXINFO* lpMMI)
{
    // Call base version:

    CFrameWndEx::OnGetMinMaxInfo(lpMMI);

    // Get active view:

    CScrollView *pScrollView = (CScrollView *)GetActiveView();

    if (pScrollView && pScrollView->IsKindOf(RUNTIME_CLASS(CMyFckinView)))
    {
        // Get total size of playground:

        CSize sizePlayground = pScrollView->GetTotalSize();

        // Test if the size is non-zero, i.e. there is at least one node displayed:

        if (sizePlayground.cx && sizePlayground.cy/* && !IsPrintPreview()*/)
        {
            // Set maximum window size to match our playground size:

            CRect rectClient, rectWindow;

            pScrollView->GetClientRect(&rectClient);
            this->GetWindowRect(&rectWindow);

            if (rectWindow.top > -5000 && rectWindow.left > -5000) // Avoid when minimized...
            {
                lpMMI->ptMaxTrackSize.x = sizePlayground.cx + (rectWindow.Width() -  rectClient.Width());
                lpMMI->ptMaxTrackSize.y = sizePlayground.cy + (rectWindow.Height() - rectClient.Height());

                return;
            }
        }
    }
}

This works but has one problem: When print preview is displayed (standard MFC print preview), I obviously want to allow free window resizing, so I use runtime info GetActiveView()->IsKindOf(…) to determine that active view is really my view, and not print-preview’s view (which is CPreviewViewEx). But when I close the print preview, OnGetMinMaxInfo is not called, so I’m unable to adjust frame size according to my view again. As soon as I move the window OnGetMinMaxInfo gets called again and correctly adjusts frame size, but without manually moving the window old size (to which the print preview was sized to) is retained and has ugly artifact.

What can I do? Basically if I could trap the moment when print preview is closed, I could use following trick:

// Trigger the WM_MINMAXINFO message:

CFrameWnd *pFrame = GetParentFrame();
RECT rectWindow;
pFrame->GetWindowRect(&rectWindow);
pFrame->MoveWindow(&rectWindow);

But I don’t know how to trap print-preview closure.

What I’m trying to accomplish seems quite standard: who would want to have frame window resized bigger than view’s logical size (set by SetScrollSizes())? So there should be some more natural solution maybe?

Answer 1

In your CMyFckinView, handle a message that is reliably sent when the print preview is closed and then post a user message to the mainframe which will trigger your “force minmax” code. Perhaps WM_FOCUS or WM_ACTIVATE?