MFC SDI image view issues.

Question

0.00/5 (No votes)

See more:

Hi,

I'm using the MFC ribbon template to create a SDI application.
I add a new class(Cchildview) which is inherit from CWnd to mainframe.cpp.

in my mainframe.h
CChildView m_wndView

C++

// create a view to occupy the client area of the frame
	if (!m_wndView.Create(NULL, NULL, AFX_WS_DEFAULT_VIEW,
		CRect(0, 0, 0, 0), this, AFX_IDW_PANE_FIRST, NULL))
	{
		TRACE0("Failed to create view window\n");
		return -1;
	}

in my childview.cpp, it will load the img and display in onpaint function as below.

C++

void CChildView::OnPaint()
{
	CString szFilename("baseimg.bmp");
	HBITMAP hBmp = (HBITMAP)::LoadImage(NULL, szFilename,
		IMAGE_BITMAP, 0, 0,
		LR_LOADFROMFILE | LR_CREATEDIBSECTION);

	CBitmap bmp;
	bmp.Attach(hBmp);

	CClientDC dc(this);
	CDC bmDC;
	bmDC.CreateCompatibleDC(&dc);
	CBitmap *pOldbmp = bmDC.SelectObject(&bmp);

	BITMAP  bi;
	bmp.GetBitmap(&bi);

	dc.BitBlt(0, 0, bi.bmWidth, bi.bmHeight, &bmDC, 0, 0, SRCCOPY);

	bmDC.SelectObject(pOldbmp);
}

My image is able to show at screen. But when I adjust the separator boarder, My image is disappear, and if i readjust again, it able to display, then if i adjust again, it will show again @@.
Any idea why will this happen?

What I have tried:

use other method to load the image. result still same.

Posted 3-Mar-20 22:14pm

Member 12275258

Updated 4-Mar-20 15:49pm

Add a Solution

2 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Shao Voon Wong · Answer 1 · 2020-03-04T00:42:00

Solution 1

Instead of

C++

CClientDC dc(this);

try

C++

CPaintDC dc(this);

Posted 4-Mar-20 0:42am

Shao Voon Wong

Comments

Member 12275258 4-Mar-20 9:52am

I had try below method, but still having same problem.

I load the bitmap at precreatewindows

BOOL CChildView::PreCreateWindow(CREATESTRUCT& cs)
{
	if (!CWnd::PreCreateWindow(cs))
		return FALSE;

	cs.dwExStyle |= WS_EX_CLIENTEDGE;
	cs.style &= ~WS_BORDER;
	cs.lpszClass = AfxRegisterWndClass(CS_HREDRAW | CS_VREDRAW | CS_DBLCLKS,
		::LoadCursor(NULL, IDC_ARROW), HBRUSH(COLOR_WINDOW + 1), NULL);

	//if (!ggtest)
	//{
	ggtest = true;
	CImage image;
	image.Load(_T("baseimg.bmp"));
	//CBitmap bitmap;
	m_Bitmap.Attach(image.Detach());
	//}


	return TRUE;
}

and OnPaint change to this.

void CChildView::OnPaint()
{

	CPaintDC PaintDC(this);
	HDC hDC = ::GetDC(NULL);
	// Bitmap for drawing.
	CBitmap Drawing;
	Drawing.CreateCompatibleBitmap(&PaintDC, 1600, 1200);
	COLORREF m_BkColor;
	m_BkColor = BLACK;
	// Double buffering.
	CDC MemDC1;
	CDC MemDC2;
	MemDC1.CreateCompatibleDC(&PaintDC);
	MemDC2.CreateCompatibleDC(&PaintDC);
	MemDC2.SetStretchBltMode(HALFTONE);
	MemDC2.SetBkColor(m_BkColor);
	CBitmap* pBitmap1 = MemDC1.SelectObject(&m_Bitmap);
	CBitmap* pBitmap2 = MemDC2.SelectObject(&Drawing);

	// Copy scale bitmap.
	MemDC2.StretchBlt(0, 0, 1600, 1200, &MemDC1, 0, 0, 1600, 1200, SRCCOPY);
	
	// Copy memory buffer to display.
	PaintDC.BitBlt(0, 0, 1600, 1200, &MemDC2, 0, 0, SRCCOPY);

	// Release buffers.
	MemDC1.SelectObject(pBitmap1);
	MemDC2.SelectObject(pBitmap2);
}

but the problem still persist...

Shao Voon Wong 4-Mar-20 19:16pm

You can try overriding your WM_SIZE handler so that it redraws your View after resize is done.

BEGIN_MESSAGE_MAP(CChildView, CView)
	ON_WM_SIZE() // add this line to your message map
END_MESSAGE_MAP()

void CChildView::OnSize(UINT nType, int cx, int cy)
{
    CView::OnSize(nType, cx, cy);
    Invalidate(TRUE); // add this line to redraw your CChildView
}

Member 12275258 4-Mar-20 21:50pm

Hi,

Thx you, but still having the same problem if apply OnSize().

Member 12275258 · Answer 2 · 2020-03-04T15:50:00

Solution 2

Hi,

I already solved it by just load and display (Ondraw function) the image in view class.

Thank You.

Posted 4-Mar-20 15:50pm

Member 12275258

Comments

Shao Voon Wong 4-Mar-20 22:55pm

By right, you only load the image once and display it in OnDraw().