ECAD

// Filename: ScrollHelper.cpp
// 2005-07-01 nschan Initial revision.
// 2005-09-08 nschan Added GetClientRectSB() function.

#include "stdafx.h"
#include "debug.h"
#include "Scroller.h"

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

// ............................................................................
void WinScroller::SetTargetSize(int targetWidth, int targetHeight)
{
	scroller_target_size = CSize(targetWidth, targetHeight);

	//if (m_attachWnd != NULL && ::IsWindow(m_attachWnd->m_hWnd))
	//	UpdateScrollInfo();
}

// ............................................................................
BOOL WinScroller::OnMouseWheel(CSize ratio, CPoint ptMouse)
{
	if (m_attachWnd == NULL)
		return FALSE;

	//TODO, should be otional to zoom on current mouse position
	::ScreenToClient(m_attachWnd->GetSafeHwnd(), &ptMouse);

	CRect rect;
	GetClientRectSB(m_attachWnd, rect);

	CPoint new_size(::MulDiv(ratio.cy, scroller_target_size.cx, ratio.cx), ::MulDiv(ratio.cy, scroller_target_size.cy, ratio.cx));
	std::cout << "new scroll size: " << scroller_target_size << std::endl;
	if (bEnabled)
	{
		scroller_target_size = new_size;
		CPoint new_cent(ptMouse + m_scrollPos);
		CPoint new_spos(::MulDiv(ratio.cy, new_cent.x, ratio.cx), ::MulDiv(ratio.cy, new_cent.y, ratio.cx));
		m_scrollPos = new_spos;
	}
	else
	{
		auto x = new_size.x - scroller_target_size.cx;
		x = ::MulDiv(x, ptMouse.x, scroller_target_size.cx);
		m_scrollPos.cx += x;
		auto y = new_size.y - scroller_target_size.cy;
		y = ::MulDiv(y, ptMouse.y, scroller_target_size.cy);
		m_scrollPos.cy += y;
		scroller_target_size = new_size;
	}

	UpdateScrollInfo();
	return TRUE;
}

// ............................................................................
bool WinScroller::UpdateScrollInfo()
{
	if (m_attachWnd == NULL)
		return false;

	// Get the width/height of the attached wnd that includes the area
	// covered by the scrollbars (if any). The reason we need this is
	// because when scrollbars are present, both cx/cy and GetClientRect()
	// when accessed from OnSize() do not include the scrollbar covered
	// areas. In other words, their values are smaller than what you would
	// expect.
	CRect rect;
	GetClientRectSB(m_attachWnd, rect);
	scroller_screen_size.SetSize(rect.Width(), rect.Height());

	std::cout << "UpdateScrollInfo: "
		<< " target: " << scroller_target_size
		<< " screen: " << scroller_screen_size
		<< " pos: " << GetScrollPos() << std::endl;
	CSize windowSize(rect.Width(), rect.Height());

	if (!bEnabled && bInit)
		return false;

	CSize deltaPos(0, 0);
	UpdateScrollBar(SB_HORZ, windowSize.cx, scroller_target_size.cx, scroller_screen_size.cx, m_scrollPos.cx, deltaPos.cx);

	UpdateScrollBar(SB_VERT, windowSize.cy, scroller_target_size.cy, scroller_screen_size.cy, m_scrollPos.cy, deltaPos.cy);
	bInit = true;
	return false;
}

// ............................................................................
void WinScroller::UpdateScrollBar(int bar, int windowSize, int displaySize,
                                    LONG& pageSize, LONG& scrollPos, LONG& deltaPos)
{
	//std::cout << "UpdateScrollBar: " << displaySize << std::endl;
    int scrollMax= 0;
    deltaPos= 0;
    if ( windowSize < displaySize && bEnabled )
    {
        scrollMax= displaySize - 1;
        pageSize= windowSize;
        scrollPos= min( scrollPos, displaySize - pageSize - 1 );
        deltaPos= m_attachWnd->GetScrollPos( bar ) - scrollPos;
    }
    else
    {
        // Force the scrollbar to go away.
        pageSize= 0;
        scrollPos= 0;
        deltaPos= m_attachWnd->GetScrollPos( bar );
    }

	SCROLLINFO si= { 0 };
    si.cbSize=	sizeof( SCROLLINFO );
    si.fMask=	SIF_ALL;    // SIF_ALL = SIF_PAGE | SIF_RANGE | SIF_POS;
    si.nMin=	0;
    si.nMax=	scrollMax;
    si.nPage=	pageSize;
    si.nPos=	scrollPos;
    m_attachWnd->SetScrollInfo( bar, &si, TRUE );
}

// ............................................................................
int WinScroller::Get32BitScrollPos(int bar, CScrollBar* pScrollBar)
{
    // Code below is from MSDN Article ID 152252, "How To Get
    // 32-bit Scroll Position During Scroll Messages".

    // First determine if the user scrolled a scroll bar control
    // on the window or scrolled the window itself.
    ASSERT( m_attachWnd != NULL );
    HWND hWndScroll;
    if ( pScrollBar == NULL )
        hWndScroll = m_attachWnd->m_hWnd;
    else
        hWndScroll = pScrollBar->m_hWnd;

    SCROLLINFO si;
    si.cbSize = sizeof(SCROLLINFO);
    si.fMask = SIF_TRACKPOS;
    ::GetScrollInfo(hWndScroll, bar, &si);

    int scrollPos = si.nTrackPos;

    return scrollPos;
}

// ............................................................................
void WinScroller::OnHScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar)
{
    if ( m_attachWnd == NULL )
        return;

    const int lineOffset = 2;

    // Compute the desired change or delta in scroll position.
    int deltaPos = 0;
    switch( nSBCode )
    {
    case SB_LINELEFT:
        // Left scroll arrow was pressed.
        deltaPos = -lineOffset;
        break;

    case SB_LINERIGHT:
        // Right scroll arrow was pressed.
        deltaPos = lineOffset;
        break;

    case SB_PAGELEFT:
        // User clicked inbetween left arrow and thumb.
        deltaPos = -scroller_screen_size.cx;
        break;

    case SB_PAGERIGHT:
        // User clicked inbetween thumb and right arrow.
        deltaPos = scroller_screen_size.cx;
        break;

    case SB_THUMBTRACK:
        // Scrollbar thumb is being dragged.
        deltaPos = Get32BitScrollPos(SB_HORZ, pScrollBar) - m_scrollPos.cx;
        break;

    case SB_THUMBPOSITION:
        // Scrollbar thumb was released.
        deltaPos = Get32BitScrollPos(SB_HORZ, pScrollBar) - m_scrollPos.cx;
        break;

    default:
        // We don't process other scrollbar messages.
        return;
    }

    // Compute the new scroll position.
    int newScrollPos = m_scrollPos.cx + deltaPos;

    // If the new scroll position is negative, we adjust
    // deltaPos in order to scroll the window back to origin.
    if ( newScrollPos < 0 )
        deltaPos = -m_scrollPos.cx;

    // If the new scroll position is greater than the max scroll position,
    // we adjust deltaPos in order to scroll the window precisely to the
    // maximum position.
    int maxScrollPos = scroller_target_size.cx - scroller_screen_size.cx;
    if ( newScrollPos > maxScrollPos )
        deltaPos = maxScrollPos - m_scrollPos.cx;

    // Scroll the window if needed.
    if ( deltaPos != 0 )
    {
        m_scrollPos.cx += deltaPos;
        m_attachWnd->SetScrollPos(SB_HORZ, m_scrollPos.cx, TRUE);
        m_attachWnd->ScrollWindow(-deltaPos, 0);
    }
}

// ............................................................................
void WinScroller::OnVScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar)
{
    if ( m_attachWnd == NULL )
        return;

    const int lineOffset = 60;

    // Compute the desired change or delta in scroll position.
    int deltaPos = 0;
    switch( nSBCode )
    {
    case SB_LINEUP:
        // Up arrow button on scrollbar was pressed.
        deltaPos = -lineOffset;
        break;

    case SB_LINEDOWN:
        // Down arrow button on scrollbar was pressed.
        deltaPos = lineOffset;
        break;

    case SB_PAGEUP:
        // User clicked inbetween up arrow and thumb.
        deltaPos = -scroller_screen_size.cy;
        break;

    case SB_PAGEDOWN:
        // User clicked inbetween thumb and down arrow.
        deltaPos = scroller_screen_size.cy;
        break;

    case SB_THUMBTRACK:
        // Scrollbar thumb is being dragged.
        deltaPos = Get32BitScrollPos(SB_VERT, pScrollBar) - m_scrollPos.cy;
        break;

    case SB_THUMBPOSITION:
        // Scrollbar thumb was released.
        deltaPos = Get32BitScrollPos(SB_VERT, pScrollBar) - m_scrollPos.cy;
        break;

    default:
        // We don't process other scrollbar messages.
        return;
    }

    // Compute the new scroll position.
    int newScrollPos = m_scrollPos.cy + deltaPos;

    // If the new scroll position is negative, we adjust
    // deltaPos in order to scroll the window back to origin.
    if ( newScrollPos < 0 )
        deltaPos = -m_scrollPos.cy;

    // If the new scroll position is greater than the max scroll position,
    // we adjust deltaPos in order to scroll the window precisely to the
    // maximum position.
    int maxScrollPos = scroller_target_size.cy - scroller_screen_size.cy;
    if ( newScrollPos > maxScrollPos )
        deltaPos = maxScrollPos - m_scrollPos.cy;

    // Scroll the window if needed.
    if ( deltaPos != 0 )
    {
        m_scrollPos.cy += deltaPos;
        m_attachWnd->SetScrollPos(SB_VERT, m_scrollPos.cy, TRUE);
        m_attachWnd->ScrollWindow(0, -deltaPos);
    }
}

// ............................................................................
// Helper function to get client rect with possible
// modification by adding scrollbar width/height.
void GetClientRectSB( CWnd* pWnd, CRect& rect )
{
    ASSERT( pWnd != NULL );

    CRect winRect;
    pWnd->GetWindowRect( &winRect );
    pWnd->ScreenToClient( &winRect );

    pWnd->GetClientRect( &rect );

    int cxSB = ::GetSystemMetrics( SM_CXVSCROLL );
    int cySB = ::GetSystemMetrics( SM_CYHSCROLL );

    if( winRect.right >= rect.right + cxSB )
        rect.right+= cxSB;
    if( winRect.bottom >= rect.bottom + cySB )
        rect.bottom+= cySB;
}

// ............................................................................
void WinScroller::ScrollToOrigin( bool scrollLeft, bool scrollTop )
{
    if ( m_attachWnd == NULL )
        return;

    if ( scrollLeft )
    {
        if ( scroller_target_size.cx > 0 && scroller_screen_size.cx > 0 && m_scrollPos.cx > 0 )
        {
            int deltaPos = -m_scrollPos.cx;
            m_scrollPos.cx += deltaPos;
            m_attachWnd->SetScrollPos(SB_HORZ, m_scrollPos.cx, TRUE);
            m_attachWnd->ScrollWindow(-deltaPos, 0);
        }
    }

    if ( scrollTop )
    {
        if ( scroller_target_size.cy > 0 && scroller_screen_size.cy > 0 && m_scrollPos.cy > 0 )
        {
            int deltaPos = -m_scrollPos.cy;
            m_scrollPos.cy += deltaPos;
            m_attachWnd->SetScrollPos(SB_VERT, m_scrollPos.cy, TRUE);
            m_attachWnd->ScrollWindow(0, -deltaPos);
        }
    }
}

// END