MFC动态画矩形（响应WM_MOUSEMOVE）

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wwkaven 2023-07-14 18:50:28 博主文章分类：GDI+ ©著作权

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VS2010，基于对话框工程MFC示例

GDI版：

1、DrawRectDlg.h

// DrawRectDlg.h : 头文件
//

#pragma once


// CDrawRectDlg 对话框
class CDrawRectDlg : public CDialogEx
{
// 构造
public:
	CDrawRectDlg(CWnd* pParent = NULL);	// 标准构造函数

// 对话框数据
	enum { IDD = IDD_DRAWRECT_DIALOG };

	protected:
	virtual void DoDataExchange(CDataExchange* pDX);	// DDX/DDV 支持


// 实现
protected:
	HICON m_hIcon;

	CPoint m_ptbegin;
	CPoint m_ptEnd;
	BOOL m_blBtnDown;
	CDC m_dcMemory;

	

	// 生成的消息映射函数
	virtual BOOL OnInitDialog();
	afx_msg void OnSysCommand(UINT nID, LPARAM lParam);
	afx_msg void OnPaint();
	afx_msg HCURSOR OnQueryDragIcon();
	DECLARE_MESSAGE_MAP()
public:
	afx_msg void OnLButtonDown(UINT nFlags, CPoint point);
	afx_msg void OnLButtonUp(UINT nFlags, CPoint point);
	afx_msg void OnMouseMove(UINT nFlags, CPoint point);
};

2、DrawRectDlg.cpp

// DrawRectDlg.cpp : 实现文件
//

#include "stdafx.h"
#include "DrawRect.h"
#include "DrawRectDlg.h"
#include "afxdialogex.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#endif


// 用于应用程序“关于”菜单项的 CAboutDlg 对话框

class CAboutDlg : public CDialogEx
{
public:
	CAboutDlg();

// 对话框数据
	enum { IDD = IDD_ABOUTBOX };

	protected:
	virtual void DoDataExchange(CDataExchange* pDX);    // DDX/DDV 支持

// 实现
protected:
	DECLARE_MESSAGE_MAP()
};

CAboutDlg::CAboutDlg() : CDialogEx(CAboutDlg::IDD)
{
}

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

BEGIN_MESSAGE_MAP(CAboutDlg, CDialogEx)
END_MESSAGE_MAP()


// CDrawRectDlg 对话框




CDrawRectDlg::CDrawRectDlg(CWnd* pParent /*=NULL*/)
	: CDialogEx(CDrawRectDlg::IDD, pParent)
	, m_ptbegin(0, 0)
	, m_ptEnd(0, 0)
	, m_blBtnDown(FALSE)
{
	m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
}

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

BEGIN_MESSAGE_MAP(CDrawRectDlg, CDialogEx)
	ON_WM_SYSCOMMAND()
	ON_WM_PAINT()
	ON_WM_QUERYDRAGICON()
	ON_WM_LBUTTONDOWN()
	ON_WM_LBUTTONUP()
	ON_WM_MOUSEMOVE()
END_MESSAGE_MAP()


// CDrawRectDlg 消息处理程序

BOOL CDrawRectDlg::OnInitDialog()
{
	CDialogEx::OnInitDialog();

	// 将“关于...”菜单项添加到系统菜单中。

	// IDM_ABOUTBOX 必须在系统命令范围内。
	ASSERT((IDM_ABOUTBOX & 0xFFF0) == IDM_ABOUTBOX);
	ASSERT(IDM_ABOUTBOX < 0xF000);

	CMenu* pSysMenu = GetSystemMenu(FALSE);
	if (pSysMenu != NULL)
	{
		BOOL bNameValid;
		CString strAboutMenu;
		bNameValid = strAboutMenu.LoadString(IDS_ABOUTBOX);
		ASSERT(bNameValid);
		if (!strAboutMenu.IsEmpty())
		{
			pSysMenu->AppendMenu(MF_SEPARATOR);
			pSysMenu->AppendMenu(MF_STRING, IDM_ABOUTBOX, strAboutMenu);
		}
	}

	// 设置此对话框的图标。当应用程序主窗口不是对话框时，框架将自动
	//  执行此操作
	SetIcon(m_hIcon, TRUE);			// 设置大图标
	SetIcon(m_hIcon, FALSE);		// 设置小图标

	// TODO: 在此添加额外的初始化代码

	return TRUE;  // 除非将焦点设置到控件，否则返回 TRUE
}

void CDrawRectDlg::OnSysCommand(UINT nID, LPARAM lParam)
{
	if ((nID & 0xFFF0) == IDM_ABOUTBOX)
	{
		CAboutDlg dlgAbout;
		dlgAbout.DoModal();
	}
	else
	{
		CDialogEx::OnSysCommand(nID, lParam);
	}
}

// 如果向对话框添加最小化按钮，则需要下面的代码
//  来绘制该图标。对于使用文档/视图模型的 MFC 应用程序，
//  这将由框架自动完成。

void CDrawRectDlg::OnPaint()
{
	if (IsIconic())
	{
		CPaintDC dc(this); // 用于绘制的设备上下文

		SendMessage(WM_ICONERASEBKGND, reinterpret_cast<WPARAM>(dc.GetSafeHdc()), 0);

		// 使图标在工作区矩形中居中
		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;

		// 绘制图标
		dc.DrawIcon(x, y, m_hIcon);
	}
	else
	{
		CPaintDC dc(this);

		CRect rc(m_ptbegin, m_ptEnd);
		rc.NormalizeRect();
		dc.Rectangle(&rc);

		CDialogEx::OnPaint();
	}
}

//当用户拖动最小化窗口时系统调用此函数取得光标
//显示。
HCURSOR CDrawRectDlg::OnQueryDragIcon()
{
	return static_cast<HCURSOR>(m_hIcon);
}



void CDrawRectDlg::OnLButtonDown(UINT nFlags, CPoint point)
{
	// TODO: 在此添加消息处理程序代码和/或调用默认值
	m_ptbegin = point;
	m_blBtnDown = TRUE;

	CDC* pDC = GetDC();

	CRect rcClient;
	GetClientRect(&rcClient);

	CBitmap oBitmap;
	oBitmap.CreateCompatibleBitmap(pDC, rcClient.Width(), rcClient.Height());

	if (m_dcMemory.m_hDC != NULL)
	{
		m_dcMemory.DeleteDC();
	}
	m_dcMemory.CreateCompatibleDC(pDC);
	m_dcMemory.SelectObject(&oBitmap);
	m_dcMemory.BitBlt(0, 0, rcClient.Width(), rcClient.Height(), pDC, 0, 0, SRCCOPY);

	oBitmap.DeleteObject();

	ReleaseDC(pDC);

	CDialogEx::OnLButtonDown(nFlags, point);
}


void CDrawRectDlg::OnLButtonUp(UINT nFlags, CPoint point)
{
	// TODO: 在此添加消息处理程序代码和/或调用默认值
	m_ptEnd = point;
	m_blBtnDown = FALSE;
	m_dcMemory.DeleteDC();
	Invalidate();

	CDialogEx::OnLButtonUp(nFlags, point);
}


void CDrawRectDlg::OnMouseMove(UINT nFlags, CPoint point)
{
	// TODO: 在此添加消息处理程序代码和/或调用默认值
	if (m_blBtnDown)
	{
		CDC* pDC = GetDC();

		CRect rcClient;
		GetClientRect(&rcClient);

		pDC->BitBlt(0, 0, rcClient.Width(), rcClient.Height(), &m_dcMemory, 0, 0, SRCCOPY);
		CRect rc(m_ptbegin, point);
		rc.NormalizeRect();
		pDC->Rectangle(&rc);

		ReleaseDC(pDC);
	}


	CDialogEx::OnMouseMove(nFlags, point);
}

3、源码：

GDI+版：

4、GDI_Plus_DrawRectDlg.h

// GDI_Plus_DrawRectDlg.h : 头文件
//

#pragma once

#include "gdiplus.h"  
#pragma comment(lib, "gdiplus.lib")  
using namespace Gdiplus;  

// CGDI_Plus_DrawRectDlg 对话框
class CGDI_Plus_DrawRectDlg : public CDialogEx
{
// 构造
public:
	CGDI_Plus_DrawRectDlg(CWnd* pParent = NULL);	// 标准构造函数

// 对话框数据
	enum { IDD = IDD_GDI_PLUS_DRAWRECT_DIALOG };

	protected:
	virtual void DoDataExchange(CDataExchange* pDX);	// DDX/DDV 支持


// 实现
protected:
	HICON m_hIcon;

	ULONG_PTR m_gdiplusToken; 

	Point m_ptBegin;
	Point m_ptEnd;
	BOOL m_bLBtnDown;
	CDC m_dcMemory;

	// 生成的消息映射函数
	virtual BOOL OnInitDialog();
	afx_msg void OnSysCommand(UINT nID, LPARAM lParam);
	afx_msg void OnPaint();
	afx_msg HCURSOR OnQueryDragIcon();
	DECLARE_MESSAGE_MAP()
public:
	afx_msg void OnDestroy();
	afx_msg void OnLButtonDown(UINT nFlags, CPoint point);
	afx_msg void OnLButtonUp(UINT nFlags, CPoint point);
	afx_msg BOOL OnEraseBkgnd(CDC* pDC);
	afx_msg void OnMouseMove(UINT nFlags, CPoint point);
};

5、GDI_Plus_DrawRectDlg.cpp

// GDI_Plus_DrawRectDlg.cpp : 实现文件
//

#include "stdafx.h"
#include "GDI_Plus_DrawRect.h"
#include "GDI_Plus_DrawRectDlg.h"
#include "afxdialogex.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#endif


// 用于应用程序“关于”菜单项的 CAboutDlg 对话框

class CAboutDlg : public CDialogEx
{
public:
	CAboutDlg();

// 对话框数据
	enum { IDD = IDD_ABOUTBOX };

	protected:
	virtual void DoDataExchange(CDataExchange* pDX);    // DDX/DDV 支持

// 实现
protected:
	DECLARE_MESSAGE_MAP()
};

CAboutDlg::CAboutDlg() : CDialogEx(CAboutDlg::IDD)
{
}

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

BEGIN_MESSAGE_MAP(CAboutDlg, CDialogEx)
END_MESSAGE_MAP()


// CGDI_Plus_DrawRectDlg 对话框




CGDI_Plus_DrawRectDlg::CGDI_Plus_DrawRectDlg(CWnd* pParent /*=NULL*/)
	: CDialogEx(CGDI_Plus_DrawRectDlg::IDD, pParent)
	, m_bLBtnDown(FALSE)
{
	m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);

	// init gdi+
	GdiplusStartupInput input;  
	GdiplusStartup(&m_gdiplusToken, &input, NULL);

	m_ptBegin = Point(0, 0);
	m_ptEnd = Point(0, 0);
}

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

BEGIN_MESSAGE_MAP(CGDI_Plus_DrawRectDlg, CDialogEx)
	ON_WM_SYSCOMMAND()
	ON_WM_PAINT()
	ON_WM_QUERYDRAGICON()
	ON_WM_DESTROY()
	ON_WM_LBUTTONDOWN()
	ON_WM_LBUTTONUP()
	ON_WM_ERASEBKGND()
	ON_WM_MOUSEMOVE()
END_MESSAGE_MAP()


// CGDI_Plus_DrawRectDlg 消息处理程序

BOOL CGDI_Plus_DrawRectDlg::OnInitDialog()
{
	CDialogEx::OnInitDialog();

	// 将“关于...”菜单项添加到系统菜单中。

	// IDM_ABOUTBOX 必须在系统命令范围内。
	ASSERT((IDM_ABOUTBOX & 0xFFF0) == IDM_ABOUTBOX);
	ASSERT(IDM_ABOUTBOX < 0xF000);

	CMenu* pSysMenu = GetSystemMenu(FALSE);
	if (pSysMenu != NULL)
	{
		BOOL bNameValid;
		CString strAboutMenu;
		bNameValid = strAboutMenu.LoadString(IDS_ABOUTBOX);
		ASSERT(bNameValid);
		if (!strAboutMenu.IsEmpty())
		{
			pSysMenu->AppendMenu(MF_SEPARATOR);
			pSysMenu->AppendMenu(MF_STRING, IDM_ABOUTBOX, strAboutMenu);
		}
	}

	// 设置此对话框的图标。当应用程序主窗口不是对话框时，框架将自动
	//  执行此操作
	SetIcon(m_hIcon, TRUE);			// 设置大图标
	SetIcon(m_hIcon, FALSE);		// 设置小图标

	// TODO: 在此添加额外的初始化代码

	return TRUE;  // 除非将焦点设置到控件，否则返回 TRUE
}

void CGDI_Plus_DrawRectDlg::OnSysCommand(UINT nID, LPARAM lParam)
{
	if ((nID & 0xFFF0) == IDM_ABOUTBOX)
	{
		CAboutDlg dlgAbout;
		dlgAbout.DoModal();
	}
	else
	{
		CDialogEx::OnSysCommand(nID, lParam);
	}
}

// 如果向对话框添加最小化按钮，则需要下面的代码
//  来绘制该图标。对于使用文档/视图模型的 MFC 应用程序，
//  这将由框架自动完成。

void CGDI_Plus_DrawRectDlg::OnPaint()
{
	if (IsIconic())
	{
		CPaintDC dc(this); // 用于绘制的设备上下文

		SendMessage(WM_ICONERASEBKGND, reinterpret_cast<WPARAM>(dc.GetSafeHdc()), 0);

		// 使图标在工作区矩形中居中
		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;

		// 绘制图标
		dc.DrawIcon(x, y, m_hIcon);
	}
	else
	{
		CPaintDC dc(this);

		CRect rc(m_ptBegin.X, m_ptBegin.Y, m_ptEnd.X, m_ptEnd.Y);
		rc.NormalizeRect();

		Pen pen(Color::Red, 2);
		Graphics graphics(dc.m_hDC);
		graphics.DrawRectangle(&pen, Rect(rc.left, rc.top, rc.Width(), rc.Height()));

		CDialogEx::OnPaint();
	}
}

//当用户拖动最小化窗口时系统调用此函数取得光标
//显示。
HCURSOR CGDI_Plus_DrawRectDlg::OnQueryDragIcon()
{
	return static_cast<HCURSOR>(m_hIcon);
}



void CGDI_Plus_DrawRectDlg::OnDestroy()
{
	CDialogEx::OnDestroy();

	// TODO: 在此处添加消息处理程序代码
	GdiplusShutdown(m_gdiplusToken);  
}


void CGDI_Plus_DrawRectDlg::OnLButtonDown(UINT nFlags, CPoint point)
{
	// TODO: 在此添加消息处理程序代码和/或调用默认值
	m_ptBegin = Point(point.x, point.y);
	m_bLBtnDown = TRUE;

	CDC* pDC = GetDC();

	CRect rcClient;
	GetClientRect(&rcClient);

	CBitmap oBitmap;
	oBitmap.CreateCompatibleBitmap(pDC, rcClient.Width(), rcClient.Height());

	m_dcMemory.CreateCompatibleDC(pDC);
	m_dcMemory.SelectObject(&oBitmap);
	m_dcMemory.BitBlt(0, 0, rcClient.Width(), rcClient.Height(), pDC, 0, 0, SRCCOPY);

	oBitmap.DeleteObject();

	ReleaseDC(pDC);

	CDialogEx::OnLButtonDown(nFlags, point);
}


void CGDI_Plus_DrawRectDlg::OnLButtonUp(UINT nFlags, CPoint point)
{
	// TODO: 在此添加消息处理程序代码和/或调用默认值
	m_ptEnd = Point(point.x, point.y);
	m_bLBtnDown = FALSE;
	m_dcMemory.DeleteDC();
	Invalidate();

	CDialogEx::OnLButtonUp(nFlags, point);
}


BOOL CGDI_Plus_DrawRectDlg::OnEraseBkgnd(CDC* pDC)
{
	// TODO: 在此添加消息处理程序代码和/或调用默认值

	return TRUE;
	//return CDialogEx::OnEraseBkgnd(pDC);
}


void CGDI_Plus_DrawRectDlg::OnMouseMove(UINT nFlags, CPoint point)
{
	// TODO: 在此添加消息处理程序代码和/或调用默认值

	if (m_bLBtnDown)
	{
		CDC* pDC = GetDC();

		CRect rcClient;
		GetClientRect(&rcClient);

		pDC->BitBlt(0, 0, rcClient.Width(), rcClient.Height(), &m_dcMemory, 0, 0, SRCCOPY);

		CRect rc(m_ptBegin.X, m_ptBegin.Y, point.x, point.y);
		rc.NormalizeRect();

		Pen pen(Color::Red, 2);
		Graphics graphics(pDC->m_hDC);
		graphics.DrawRectangle(&pen, Rect(rc.left, rc.top, rc.Width(), rc.Height()));

		ReleaseDC(pDC);
	}

	CDialogEx::OnMouseMove(nFlags, point);
}

6、源码：