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#ifndef _MEMDC_H_
#define _MEMDC_H_
//////////////////////////////////////////////////
// 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.
namespace KRule {
class CMemDC : 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:
CMemDC(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 relevent 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());
}
~CMemDC()
{
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
CMemDC* operator->()
{
return this;
}
// Allow usage as a pointer
operator CMemDC*()
{
return this;
}
};
} // namespace KRule
#endif
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Graduated at the Faculty of Electrical Engineering and Computing, University of Zagreb (Croatia) and received M.Sc. degree in electronics. For several years he was research and lecturing assistant in the fields of solid state electronics and electronic circuits, published several scientific and professional papers, as well as a book "Physics of Semiconductor Devices - Solved Problems with Theory" (in Croatian).
During that work he gained interest in C++ programming language and have co-written
"C++ Demystified" (in Croatian), 1
st edition published in 1997, 2
nd in 2001, 3
rd in 2010,
4th in 2014.
After book publication, completely switched to software development, programming mostly in C++ and in C#.
In 2016 coauthored the book
"Python for Curious" (in Croatian).