DoubleBuffering.cpp

#include "pch.h"
#include "framework.h"
#include "DoubleBuffering.h"
#include "DoubleBufferingDlg.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#endif

BEGIN_MESSAGE_MAP(CDoubleBufferingApp, CWinApp)
	ON_COMMAND(ID_HELP, &CWinApp::OnHelp)
END_MESSAGE_MAP()

CDoubleBufferingApp::CDoubleBufferingApp() : m_rect(CRect(0, 0, 10, 10))
{
}

CDoubleBufferingApp theApp;

BOOL CDoubleBufferingApp::InitInstance()
{
	CWinApp::InitInstance();
	SetRegistryKey(_T("MyApp"));
	CDoubleBufferingDlg* dlg = new CDoubleBufferingDlg(this);
	m_pMainWnd = dlg;
	dlg->Create(IDD_DOUBLEBUFFERING_DIALOG);
	dlg->ShowWindow(SW_SHOW);
	return DoLoop();
}

BOOL CDoubleBufferingApp::DoLoop()
{
	MSG msg;
	BOOL ret;
	while ((ret = GetMessage(&msg, nullptr, 0, 0)) != 0) {
		if (ret == -1)
			continue;
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}
	return (BOOL)msg.wParam;
}

void CDoubleBufferingApp::StartAnimation()
{
	GetDlg()->StartAnimation();
}

void CDoubleBufferingApp::StopAnimation()
{
	GetDlg()->StopAnimation();
}

CDoubleBufferingDlg* CDoubleBufferingApp::GetDlg()
{
	return (CDoubleBufferingDlg*)m_pMainWnd;
}

void CDoubleBufferingApp::MoveRect(CRect client_rect)
{
	m_rect.OffsetRect(10, 10);
	if (m_rect.top > client_rect.bottom)
		m_rect.MoveToY(0);
	if (m_rect.left > client_rect.right)
		m_rect.MoveToX(0);
	GetDlg()->Invalidate();
	GetDlg()->UpdateWindow();
}

CRect CDoubleBufferingApp::GetRect()
{
	return m_rect;
}

DoubleBuffering.h

#pragma once

#include "resource.h"

class CDoubleBufferingDlg;

class CDoubleBufferingApp : public CWinApp
{
public:
	CDoubleBufferingApp();
	virtual ~CDoubleBufferingApp() {}
	virtual BOOL InitInstance();
	virtual void MoveRect(CRect client_rect);
	virtual CRect GetRect();
	virtual void StartAnimation();
	virtual void StopAnimation();

private:
	virtual CDoubleBufferingDlg* GetDlg();
	virtual BOOL DoLoop();

private:
	CRect m_rect;

	DECLARE_MESSAGE_MAP()
};

extern CDoubleBufferingApp theApp;

DoubleBufferingDlg.cpp

#include "pch.h"
#include "framework.h"
#include "DoubleBuffering.h"
#include "DoubleBufferingDlg.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#endif

CDoubleBufferingDlg::CDoubleBufferingDlg(CDoubleBufferingApp * app, CWnd* pParent)
	: CDialogEx(IDD_DOUBLEBUFFERING_DIALOG, pParent),
	  m_app(app)
{
	m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
}

void CDoubleBufferingDlg::DoDataExchange(CDataExchange* pDX)
{
	CDialogEx::DoDataExchange(pDX);
}

BEGIN_MESSAGE_MAP(CDoubleBufferingDlg, CDialogEx)
	ON_WM_PAINT()
	ON_WM_QUERYDRAGICON()
	ON_WM_TIMER()
	ON_WM_ERASEBKGND()
END_MESSAGE_MAP()

BOOL CDoubleBufferingDlg::OnInitDialog()
{
	CDialogEx::OnInitDialog();
	SetIcon(m_hIcon, TRUE);
	SetIcon(m_hIcon, FALSE);
	return TRUE;
}

void CDoubleBufferingDlg::OnPaint()
{
	if (IsIconic()) {
		OnPaintIconic();
		return;
	}
	CPaintDC dc(this);
	DrawRect(&dc);
}

void CDoubleBufferingDlg::DrawRect(CDC * dc)
{
	CDC bufdc;
	bufdc.CreateCompatibleDC(dc);
	CRect cli_rect;
	GetClientRect(cli_rect);
	CBitmap bufbm;
	bufbm.CreateCompatibleBitmap(dc, cli_rect.Width(), cli_rect.Height());
	CBitmap* saved_bm = bufdc.SelectObject(&bufbm);
	{
		CBrush brush_white;
		brush_white.CreateSolidBrush(RGB(255, 255, 255));
		bufdc.FillRect(cli_rect, &brush_white);
		CBrush brush_red;
		brush_red.CreateSolidBrush(RGB(255, 0, 0));
		CRect rect = m_app->GetRect();
		bufdc.FillRect(rect, &brush_red);
		dc->BitBlt(0, 0, cli_rect.Width(), cli_rect.Height(), &bufdc, 0, 0, SRCCOPY);
	}
	bufdc.SelectObject(saved_bm);
}

void CDoubleBufferingDlg::OnPaintIconic()
{
	CPaintDC dc(this);
	SendMessage(WM_ICONERASEBKGND, reinterpret_cast<WPARAM>(dc.GetSafeHdc()), 0);
	int cxIcon = GetSystemMetrics(SM_CXICON);
	int cyIcon = GetSystemMetrics(SM_CYICON);
	CRect rect;
	GetClientRect(&rect);
	int x = (rect.Width() - cxIcon + 1) / 2;
	int y = (rect.Height() - cyIcon + 1) / 2;
	dc.DrawIcon(x, y, m_hIcon);
}

HCURSOR CDoubleBufferingDlg::OnQueryDragIcon()
{
	return static_cast<HCURSOR>(m_hIcon);
}

void CDoubleBufferingDlg::OnTimer(UINT_PTR id)
{
	CRect rect;
	GetClientRect(&rect);
	m_app->MoveRect(rect);
}

void CDoubleBufferingDlg::StartAnimation()
{
	SetTimer((UINT_PTR)this, 33, NULL);
}

void CDoubleBufferingDlg::StopAnimation()
{
	KillTimer((UINT_PTR)this);
}

void CDoubleBufferingDlg::OnCancel()
{
	PostQuitMessage(0);
}

void CDoubleBufferingDlg::OnOK()
{
	m_app->StartAnimation();
}

BOOL CDoubleBufferingDlg::OnEraseBkgnd(CDC* pDC)
{
	return TRUE;
}

DoubleBufferingDlg.h

#pragma once

class CDoubleBufferingApp;

class CDoubleBufferingDlg : public CDialogEx
{
public:
	CDoubleBufferingDlg(CDoubleBufferingApp* app, CWnd* pParent = nullptr);
	virtual ~CDoubleBufferingDlg() {}
	afx_msg void OnTimer(UINT_PTR id);
	virtual void StartAnimation();
	virtual void StopAnimation();
	virtual void OnCancel() override;
	virtual void OnOK() override;

#ifdef AFX_DESIGN_TIME
	enum { IDD = IDD_DOUBLEBUFFERING_DIALOG };
#endif

protected:
	virtual void DoDataExchange(CDataExchange* pDX);
	virtual BOOL OnInitDialog();
	afx_msg void OnPaint();
	afx_msg HCURSOR OnQueryDragIcon();
	virtual void OnPaintIconic();
	virtual void DrawRect(CDC* dc);

protected:
	CDoubleBufferingApp* m_app;
	HICON m_hIcon;

	DECLARE_MESSAGE_MAP()
public:
	afx_msg BOOL OnEraseBkgnd(CDC* pDC);
};