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CResizableDialog

, 25 Jul 2012 CPOL
A CDialog derived class to implement resizable dialogs with MFC
// ResizableLayout.cpp: implementation of the CResizableLayout class.
//
/////////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2000-2001 by Paolo Messina
// (http://www.geocities.com/ppescher - ppescher@yahoo.com)
//
// The contents of this file are subject to the Artistic License (the "License").
// You may not use this file except in compliance with the License. 
// You may obtain a copy of the License at:
// http://www.opensource.org/licenses/artistic-license.html
//
// If you find this code useful, credits would be nice!
//
/////////////////////////////////////////////////////////////////////////////

#include "stdafx.h"
#include "ResizableLayout.h"

#ifdef _DEBUG
#undef THIS_FILE
static char THIS_FILE[]=__FILE__;
#define new DEBUG_NEW
#endif

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

#define BS_TYPEMASK SS_TYPEMASK

void CResizableLayout::AddAnchor(HWND hWnd, CSize sizeTypeTL, CSize sizeTypeBR)
{
	CWnd* pParent = GetResizableWnd();

	// child window must be valid
	ASSERT(::IsWindow(hWnd));
	// must be child of parent window
	ASSERT(::IsChild(pParent->GetSafeHwnd(), hWnd));
	// top-left anchor must be valid
	ASSERT(sizeTypeTL != NOANCHOR);

	// get control's window class
	CString st;
	GetClassName(hWnd, st.GetBufferSetLength(MAX_PATH), MAX_PATH);
	st.ReleaseBuffer();

	// add the style 'clipsiblings' to a GroupBox
	// to avoid unnecessary repainting of controls inside
	if (st == "Button")
	{
		DWORD style = GetWindowLong(hWnd, GWL_STYLE);
		if ((style & BS_TYPEMASK) == BS_GROUPBOX)
			SetWindowLong(hWnd, GWL_STYLE, style | WS_CLIPSIBLINGS);
	}

	// window classes that don't redraw client area correctly
	// when the hor scroll pos changes due to a resizing
	BOOL bHScroll = FALSE;
	if (st == "ListBox")
		bHScroll = TRUE;

	// window classes that need refresh when resized
	BOOL bRefresh = NeedsRefresh(hWnd);

	// get parent window's rect
	CRect rectParent;
	GetTotalClientRect(&rectParent);
	// and child control's rect
	CRect rectChild;
	::GetWindowRect(hWnd, &rectChild);
	pParent->ScreenToClient(&rectChild);

	// go calculate margins
	CSize sizeMarginTL, sizeMarginBR;

	if (sizeTypeBR == NOANCHOR)
		sizeTypeBR = sizeTypeTL;
	
	// calculate margin for the top-left corner

	sizeMarginTL.cx = rectChild.left - rectParent.Width() * sizeTypeTL.cx / 100;
	sizeMarginTL.cy = rectChild.top - rectParent.Height() * sizeTypeTL.cy / 100;
	
	// calculate margin for the bottom-right corner

	sizeMarginBR.cx = rectChild.right - rectParent.Width() * sizeTypeBR.cx / 100;
	sizeMarginBR.cy = rectChild.bottom - rectParent.Height() * sizeTypeBR.cy / 100;

	// add to the list
	LayoutInfo layout(hWnd, sizeTypeTL, sizeMarginTL,
		sizeTypeBR, sizeMarginBR, bHScroll, bRefresh);
	// always add before callbacks
	m_arrLayout.InsertAt(m_iFirstCallback++, layout);
}

// one callback control cannot rely upon another callback control's
// size and/or position (they're updated all together at the end)
void CResizableLayout::AddAnchorCallback(UINT nCallbackID)
{
	// add to the list
	LayoutInfo layout;
	layout.nCallbackID = nCallbackID;
	// callbacks added to tail (for efficiency)
	m_arrLayout.Add(layout);
}

BOOL CResizableLayout::ArrangeLayoutCallback(LayoutInfo& /*layout*/)
{
	ASSERT(FALSE);
	// must be overridden, if callback is used
	
	return FALSE;	// no output data
}

void CResizableLayout::ArrangeLayout()
{
	CWnd* pParent = GetResizableWnd();

	// get parent window's rect
	CRect rectParent;
	GetTotalClientRect(&rectParent);

	// init some vars
	int i, count = m_arrLayout.GetSize();
	HDWP hdwp = BeginDeferWindowPos(count);

	for (i=0; i<count; ++i)
	{
		LayoutInfo layout = m_arrLayout[i];
		
		if (layout.hWnd == NULL)	// callback
		{
			if (i == m_iFirstCallback)	// first time only
			{
				// update previous controls
				EndDeferWindowPos(hdwp);
				// start again for callback controls
				hdwp = BeginDeferWindowPos(count-i);
			}
			// callbacks are added at the end, so that
			// you don't have multiple screen updates

			if (!ArrangeLayoutCallback(layout))	// request data
				continue;
		}

		CRect rectChild, newrc;
		CWnd* pWnd = CWnd::FromHandle(layout.hWnd); // temporary solution

		pWnd->GetWindowRect(&rectChild);
		pParent->ScreenToClient(&rectChild);
		
		// calculate new top-left corner

		newrc.left = layout.sizeMarginTL.cx + rectParent.Width() * layout.sizeTypeTL.cx / 100;
		newrc.top = layout.sizeMarginTL.cy + rectParent.Height() * layout.sizeTypeTL.cy / 100;
		
		// calculate new bottom-right corner

		newrc.right = layout.sizeMarginBR.cx + rectParent.Width() * layout.sizeTypeBR.cx / 100;
		newrc.bottom = layout.sizeMarginBR.cy + rectParent.Height() * layout.sizeTypeBR.cy / 100;

		if (!newrc.EqualRect(&rectChild))
		{
			if (layout.bAdjHScroll)
			{
				// needs repainting, due to horiz scrolling
				int diff = newrc.Width() - rectChild.Width();
				int max = pWnd->GetScrollLimit(SB_HORZ);
			
				layout.bNeedRefresh = FALSE;
				if (max > 0 && pWnd->GetScrollPos(SB_HORZ) > max - diff)
				{
					layout.bNeedRefresh = TRUE;
				}
			}

			// set flags 
			DWORD flags = SWP_NOZORDER | SWP_NOACTIVATE | SWP_NOREPOSITION;
			if (layout.bNeedRefresh)
				flags |= SWP_NOCOPYBITS;
			if (newrc.TopLeft() == rectChild.TopLeft())
				flags |= SWP_NOMOVE;
			if (newrc.Size() == rectChild.Size())
				flags |= SWP_NOSIZE;
			
			hdwp = DeferWindowPos(hdwp, layout.hWnd, NULL, newrc.left, newrc.top,
				newrc.Width(), newrc.Height(), flags);
		}
	}
	// go re-arrange child windows
	EndDeferWindowPos(hdwp);
}

void CResizableLayout::EnumAndClipChildWindow(HWND hWnd, CDC* pDC)
{
	// obtain window position
	CRect rect;
	::GetWindowRect(hWnd, &rect);
	GetResizableWnd()->ScreenToClient(&rect);
	pDC->DPtoLP(&rect);

	// use window region if any
	CRgn rgn;
	rgn.CreateRectRgn(0,0,0,0);
	if (COMPLEXREGION == ::GetWindowRgn(hWnd, rgn))
	{
		rgn.OffsetRgn(rect.TopLeft());
	}
	else
	{
		rgn.SetRectRgn(&rect);
	}

	// go clipping?
	if (LikesClipping(hWnd))
		pDC->SelectClipRgn(&rgn, RGN_DIFF);
	else
		pDC->SelectClipRgn(&rgn, RGN_OR);
}

void CResizableLayout::ClipChildren(CDC *pDC)
{
	// only clips anchored controls
	for (int i=0; i<m_arrLayout.GetSize(); ++i)
	{
		HWND hWnd = m_arrLayout[i].hWnd;
		if (hWnd != NULL && ::IsWindowVisible(hWnd))
			EnumAndClipChildWindow(m_arrLayout[i].hWnd, pDC);
	}
}

void CResizableLayout::GetTotalClientRect(LPRECT lpRect)
{
	GetResizableWnd()->GetClientRect(lpRect);
}

BOOL CResizableLayout::NeedsRefresh(HWND hWnd)
{
	// get window class
	CString st;
	GetClassName(hWnd, st.GetBufferSetLength(MAX_PATH), MAX_PATH);
	st.ReleaseBuffer();

	// optimistic, no need to refresh
	BOOL bRefresh = FALSE;

	// window classes that need refresh when resized
	if (st == "Static")
	{
		DWORD style = GetWindowLong(hWnd, GWL_STYLE);

		switch (style & SS_TYPEMASK)
		{
		case SS_LEFT:
		case SS_CENTER:
		case SS_RIGHT:
		case SS_ENHMETAFILE:
		case SS_BITMAP:
			// word-wrapped text needs bRefresh
			bRefresh = TRUE;
			break;

		case SS_ICON:
		case SS_SIMPLE:
		case SS_ETCHEDHORZ:
		case SS_ETCHEDVERT:
			break;

		default:
			// centered images or text need bRefresh
			if (style & SS_CENTERIMAGE)
				bRefresh = TRUE;
		}
	}

	return bRefresh;
}

BOOL CResizableLayout::LikesClipping(HWND hWnd)
{
	// check child type
	CString st;
	GetClassName(hWnd, st.GetBufferSetLength(MAX_PATH), MAX_PATH);
	st.ReleaseBuffer();

	DWORD style = GetWindowLong(hWnd, GWL_STYLE);

	// skip windows that wants background repainted
	if (st == TOOLBARCLASSNAME && (style & TBSTYLE_TRANSPARENT))
		return FALSE;
	if (st == "Button" && (style & BS_TYPEMASK) == BS_GROUPBOX)
		return FALSE;
	if (st == "Static")
	{
		switch (style & SS_TYPEMASK)
		{
		case SS_BLACKRECT:
		case SS_GRAYRECT:
		case SS_WHITERECT:
		case SS_ETCHEDHORZ:
		case SS_ETCHEDVERT:
		case SS_BITMAP:
			break;
		case SS_ICON:
		case SS_ENHMETAFILE:
			if (style & SS_CENTERIMAGE)
				return FALSE;
			break;
		default:
			return FALSE;
		}
	}

	// assume the others like clipping
	return TRUE;
}

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

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About the Author

Paolo Messina
Software Developer RoboTech srl
Italy Italy
Paolo began programming at the age of 9 with a glorious 8086 and GW-BASIC, then he played a bit with C, ASM and Pascal. He tought himself MFC and Windows programming, to exploit his studies of C++. Always attracted by low-level programming and Assembly, he's beginning to appreciate the joys of templates and STL. At work he changed his mind about Java, discovered Eclipse IDE, and now think it's cool.
 
He lives in Follonica, Italy.
 
He has been abroad in the U.S. to work on his final thesis before graduating. For seven months he was playing with airplanes and automatic control at the Unversity of Illinois at Urbana-Champaign.
 
He graduated in Computer Science Engineering at the University of Pisa, Italy, in December 2003.
 
Currently working for an edutainment robotics company (www.robotechsrl.com).
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