#pragma once

//////////////////////////////////////////////////
// CMemDC - memory DC
//
// Author: Keith Rule
// Email:  keithr@europa.com
// Copyright 1996-2002, Keith Rule
//
// You may freely use or modify this code provided this
// Copyright is included in all derived versions.
//
// History - 10/3/97 Fixed scrolling bug.
//               Added print support. - KR
//
//       11/3/99 Fixed most common complaint. Added
//            background color fill. - KR
//
//       11/3/99 Added support for mapping modes other than
//            MM_TEXT as suggested by Lee Sang Hun. - KR
//
//       02/11/02 Added support for CScrollView as supplied
//             by Gary Kirkham. - KR
//
// This class implements a memory Device Context which allows
// flicker free drawing.

class xCMemDC : public CDC {
private:
    CBitmap    m_bitmap;        // Offscreen bitmap
    CBitmap* m_oldBitmap; // bitmap originally found in CMemDC
    CDC* m_pDC;           // Saves CDC passed in constructor
    CRect      m_rect;          // Rectangle of drawing area.
    //BOOL       m_bMemDC;        // TRUE if CDC really is a Memory DC.
public:

    xCMemDC(CDC* pDC, const CRect* pRect = NULL) : CDC()
    {
        ASSERT(pDC != NULL);

        // Some initialization
        m_pDC = pDC;
        m_oldBitmap = NULL;
        //m_bMemDC = !pDC->IsPrinting();

        // Get the rectangle to draw
        if (pRect == NULL) {
            pDC->GetClipBox(&m_rect);
        } else {
            m_rect = *pRect;
        }

        //if (m_bMemDC) {
            // Create a Memory DC
            CreateCompatibleDC(pDC);
            pDC->LPtoDP(&m_rect);

            m_bitmap.CreateCompatibleBitmap(pDC, m_rect.Width(),
                m_rect.Height());
            m_oldBitmap = SelectObject(&m_bitmap);

            SetMapMode(pDC->GetMapMode());

            SetWindowExt(pDC->GetWindowExt());
            SetViewportExt(pDC->GetViewportExt());

            pDC->DPtoLP(&m_rect);
            SetWindowOrg(m_rect.left, m_rect.top);
        //} else {
            // Make a copy of the relevant parts of the current 
            // DC for printing
            //m_bPrinting = pDC->m_bPrinting;
            //m_hDC = pDC->m_hDC;
            //m_hAttribDC = pDC->m_hAttribDC;
        //}

        // Fill background 
        //FillSolidRect(m_rect, pDC->GetBkColor());
    }

    ~xCMemDC()
    {
        //if (m_bMemDC) {
            // Copy the offscreen bitmap onto the screen.
            m_pDC->BitBlt(m_rect.left, m_rect.top,
                m_rect.Width(), m_rect.Height(),
                this, m_rect.left, m_rect.top, SRCCOPY);

            //Swap back the original bitmap.
            SelectObject(m_oldBitmap);
        //} else {
            // All we need to do is replace the DC with an illegal
            // value, this keeps us from accidentally deleting the 
            // handles associated with the CDC that was passed to 
            // the constructor.              
            //m_hDC = m_hAttribDC = NULL;
        //}
    }

    // Allow usage as a pointer    
    xCMemDC* operator->()
    {
        return this;
    }

    // Allow usage as a pointer    
    operator xCMemDC* ()
    {
        return this;
    }
};
