VC 6.0 下MFC基于对话框 绘制图形

附录表

一、具体步骤：

1、选择菜单栏的“新建”，选择MFC项目名为DrawGraphics，并设置为基于对话框的项目，如图-1、图-2所示；

图-1

图-2

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2、按下键盘上的Ctrl+W键，调出类向导，选择“Add Class”，并点击“New”添加一个颜色按钮类CColorButton，继承自CButton类，如图-3所示：

图-3

3、在CColorButton中添加如下成员变量： COLORREF color; //按钮颜色 CPoint arrays[4]; //按钮顶点坐标 BOOL IsShow; //是否显示按钮 BOOL IsPressed; //按钮是否被按下

4、右击CColorButton类，选择Add Virtul function ，重写其DraItem函数，如图-4，图-5所示：

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图-4

图-5

5、为其Drawitem函数中添加如下代码： CRect rect; GetClientRect(rect); CDC dc; dc.Attach(lpDrawItemStruct->hDC); arrays[0]=CPoint(rect.left,rect.top); arrays[1]=CPoint(rect.right,rect.top); arrays[2]=CPoint(rect.right,rect.bottom); arrays[3]=CPoint(rect.left,rect.bottom); //设置背景透明 dc.SetBkMode(TRANSPARENT); if (IsShow) { //创建一个位图画刷 CBrush brush(color); dc.SelectObject(&brush); CPen pen(PS_NULL,1,color); dc.SelectObject(&pen); dc.Rectangle(rect);

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if(IsPressed) { CPen pen(PS_DASHDOTDOT,3,RGB(0,0,0)); dc.SelectObject(&pen); dc.MoveTo(arrays[0]); for(int i=1;i<4;i++) { dc.LineTo(arrays[i]); } dc.LineTo(arrays[0]); } else { CPen pen(PS_DASHDOTDOT,2,color); dc.SelectObject(&pen); dc.MoveTo(arrays[0]); for(int i=1;i<4;i++) { dc.LineTo(arrays[i]); } dc.LineTo(arrays[0]); } //绘制按钮文本 CString str; GetWindowText(str); dc.SetTextColor(RGB(255-GetRValue(color),255-GetGValue(color),255-GetBValue(color))); dc.DrawText(str,CRect(0,0,rect.right,rect.bottom),DT_CENTER|DT_VCENTER|DT_SINGLELINE); }

6、为CColorButton添加属性设置函数：

void CColorButton::SetDrawColor(COLORREF m_color,BOOL IsShow) { this->color = m_color; this->IsShow=IsShow; }

7、为CColorButton添加WM_LBUTTONDOWN和WM_LBUTTONUP消息，其消息处理函数如下：

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void CColorButton::OnLButtonDown(UINT nFlags, CPoint point) { // TODO: Add your message handler code here and/or call default IsPressed = true; CButton::OnLButtonDown(nFlags, point); }

void CColorButton::OnLButtonUp(UINT nFlags, CPoint point) { // TODO: Add your message handler code here and/or call default IsPressed = false; CButton::OnLButtonUp(nFlags, point); }

8、为DrawGraphics项目的中的对话框资源拖拽如下控件，如图-6所示，并按表-1设置其相关ID；

图-6

ID

IDC_RADIO_RECT IDC_RADIO_ROUND IDC_RADIO_LINE IDC_RADIO_SELF IDC_RADIO_SLOIDLINE IDC_RADIO_DOTTEDLINE IDC_COMBO_LINEVALUE

作用及类别 矩形单选按钮 圆形单选按钮 直线单选按钮 涂鸦单选按钮 实线单选按钮 虚线单选按钮 线条粗细下拉列表

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IDC_STATIC_LINEEXAMPLE 显示线条粗细的Picture控件 IDC_CHECK_BORDER 是否有边界复选框 IDC_RADIO_SOLID 填充单选按钮 IDC_RADIO_GRADIENT 渐变单选按钮 IDC_RADIO_NULL 无填充单选按钮 IDC_BUTTON_FORECOLOR 前景色按钮 IDC_BUTTON_BKCOLOR 背景色按钮 IDC_RADIO_PEN 画笔单选按钮 IDC_RADIO_CLEAR 清空画板单选按钮 IDC_STATIC_GRAPHICS 画板区（Picture控件）

9、打开类向导，按图-7所示，为相关控件添加关联成员：

表-1

10、在CDrawGraphicsDlg类的OninitDialog函数中添加初始化代码： BOOL CDrawGraphicsDlg:OnInitDialog() { /*.........省略无关代码..........

.....................................................*/ // TODO: Add extra initialization here

CButton *cb; //设置相关按钮的默认选中状态 cb=(CButton *)GetDlgItem(IDC_RADIO_RECT); cb->SetCheck(1); cb=(CButton *)GetDlgItem(IDC_RADIO_SLOIDLINE); cb->SetCheck(1);

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cb=(CButton *)GetDlgItem(IDC_CHECK_BORDER); cb->SetCheck(1);

cb=(CButton *)GetDlgItem(IDC_RADIO_SOLID); cb->SetCheck(1); cb=(CButton *)GetDlgItem(IDC_RADIO_PEN); cb->SetCheck(1); m_ComboLineValue.SetCurSel(3);

m_ForeColor=RGB(255,0,0); m_BkColor=RGB(0,0,255); m_ForeCButton.SetDrawColor(m_ForeColor,TRUE); //设置前背景色按钮的颜色 m_BkCButton.SetDrawColor(m_BkColor,TRUE); m_IsPressed=FALSE; m_nWidth=4; m_nPenStyle=PS_SOLID; return TRUE; // return TRUE unless you set the focus to a control }

10、为CDrawGraphicsDlg添加WM_LBUTTONDOWN和WM_LBUTTONUP，WM_MOUSEMOVE消息，其消息处理函数如下：

void CDrawGraphicsDlg:OnLButtonDown(UINT nFlags, CPoint point) { // TODO: Add your message handler code here and/or call default m_IsPressed=TRUE; SetCursor(m_Hcursor); if (IsDlgButtonChecked(IDC_RADIO_SELF)) { m_pOld=point; } else if (IsDlgButtonChecked(IDC_RADIO_LINE)) {

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m_pOld=point; m_PointOrigin=point; }else if (IsDlgButtonChecked(IDC_RADIO_RECT)) { m_pOld=point; m_PointOrigin=point; }else if (IsDlgButtonChecked(IDC_RADIO_ROUND)) { m_pOld=point; m_PointOrigin=point; } CDialog::OnLButtonDown(nFlags, point); }

void CDrawGraphicsDlg:OnLButtonUp(UINT nFlags, CPoint point) { // TODO: Add your message handler code here and/or call default m_IsPressed=FALSE; ClipCursor(NULL); //解除鼠标的限定 CClientDC dc(this); CPen pen(m_nPenStyle,m_nWidth,m_ForeColor);

dc.SelectObject(&pen);

if (IsDlgButtonChecked(IDC_RADIO_LINE)) //选择的为画直线 { dc.SetROP2(R2_NOT); //逆转当前屏幕颜色来画线的绘图方式 dc.MoveTo(m_PointOrigin); dc.LineTo(m_pOld);//擦去上一次的临时线 dc.SetROP2(R2_COPYPEN);//缺省绘图模式，像素为画笔颜色 dc.MoveTo(m_PointOrigin); dc.LineTo(point);//绘制固定线 }

else if (IsDlgButtonChecked(IDC_RADIO_RECT)) //选择的为画矩形 { dc.SelectObject(GetStockObject(NULL_BRUSH));//选择空话刷 dc.SetROP2(R2_NOT); CRect Oldrect(m_PointOrigin,m_pOld); dc.Rectangle(&Oldrect); //清除之前的矩形绘图

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dc.SetROP2(R2_COPYPEN); CBrush brush(m_BkColor);

dc.SelectObject(&brush); //画这次的矩形 if (IsDlgButtonChecked(IDC_RADIO_NULL)) //如果选择无填充的话，使用空画刷

dc.SelectObject(GetStockObject(NULL_BRUSH)); CRect Nowrect(m_PointOrigin,point); dc.Rectangle(&Nowrect);

if (IsDlgButtonChecked(IDC_RADIO_GRADIENT))//如果选择渐变的话，调用渐变函数

DrawGradient(dc.GetSafeHdc(),Nowrect,m_ForeColor,m_BkColor,1);

}else if(IsDlgButtonChecked(IDC_RADIO_ROUND))//如果选择绘制椭圆 {

dc.SelectObject(GetStockObject(NULL_BRUSH)); dc.SetROP2(R2_NOT); CRect Oldrect(m_PointOrigin,m_pOld); dc.Ellipse(&Oldrect);

dc.SetROP2(R2_COPYPEN); CBrush brush(m_BkColor); dc.SelectObject(&brush); if (IsDlgButtonChecked(IDC_RADIO_NULL))

dc.SelectObject(GetStockObject(NULL_BRUSH)); CRect Nowrect(m_PointOrigin,point); if (IsDlgButtonChecked(IDC_RADIO_GRADIENT))//如果选择渐变的话，调用渐变函数

DrawGradient(dc.GetSafeHdc(),Nowrect,m_ForeColor,m_BkColor,1); dc.Ellipse(&Nowrect); }

InvalidateMyRect();//刷新工具区 CDialog::OnLButtonUp(nFlags, point); }

void CDrawGraphicsDlg:OnMouseMove(UINT nFlags, CPoint point)

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{ // TODO: Add your message handler code here and/or call default if (m_IsPressed&&point.x>205)//如果鼠标移动位置到达画板区 { CRect rect; m_Graphics.GetClientRect(&rect); m_Graphics.ClientToScreen(&rect); ClipCursor(rect);//限定光标在指定矩形 } CClientDC dc(this); if (m_IsPressed&&IsDlgButtonChecked(IDC_RADIO_SELF))//如果选择了涂鸦 { CPen pen(m_nPenStyle,m_nWidth,m_ForeColor); //创建画笔 dc.SelectObject(&pen); //选入画笔 dc.MoveTo(m_pOld); dc.LineTo(point);//绘制轨迹 m_pOld=point;//将当前点设置为旧点 }

else if(m_IsPressed&&IsDlgButtonChecked(IDC_RADIO_LINE))//如果选择了直线 { dc.SetROP2(R2_NOT);//逆转当前屏幕颜色来画线的绘图方式 dc.MoveTo(m_PointOrigin); dc.LineTo(m_pOld); //擦去上一次的线 dc.MoveTo(m_PointOrigin); dc.LineTo(point);//绘制这一次的临时线 m_pOld=point; }

else if(m_IsPressed&&IsDlgButtonChecked(IDC_RADIO_RECT))//如果选择了矩形 { dc.SetROP2(R2_NOT); CPen pen(PS_DOT,1,m_ForeColor); dc.SelectObject(&pen); dc.SelectObject(GetStockObject(HOLLOW_BRUSH)); CRect Oldrect(m_PointOrigin,m_pOld); dc.Rectangle(&Oldrect);

CRect Nowrect(m_PointOrigin,point); dc.Rectangle(&Nowrect); m_pOld=point; pen.DeleteObject();

}else if (m_IsPressed&&IsDlgButtonChecked(IDC_RADIO_ROUND))//如果选择了圆

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{ CClientDC dc(this); dc.SetROP2(R2_NOT); CPen pen(PS_DOT,1,m_ForeColor); dc.SelectObject(&pen); dc.SelectObject(GetStockObject(HOLLOW_BRUSH)); CRect Oldrect(m_PointOrigin,m_pOld); dc.Ellipse(&Oldrect); CRect Nowrect(m_PointOrigin,point); dc.Ellipse(&Nowrect); m_pOld=point; pen.DeleteObject(); } CDialog::OnMouseMove(nFlags, point); }

11、为背景色、前景色、无填充、实线、虚线、边框、清空画板按钮添加按钮单击消息，响应函数如下：

void CDrawGraphicsDlg:OnButtonBkcolor() { // TODO: Add your control notification handler code here CColorDialog cdg; if (cdg.DoModal()==IDOK) //调用颜色对话框 { m_BkColor=cdg.GetColor(); //更改背景色 m_BkCButton.SetDrawColor(m_BkColor,TRUE);//更改背景色按钮颜色 InvalidateMyRect(); //刷新工具区 } }

void CDrawGraphicsDlg:OnButtonForecolor() { // TODO: Add your control notification handler code here CColorDialog cdg; if (cdg.DoModal()==IDOK) { m_ForeColor=cdg.GetColor(); m_ForeCButton.SetDrawColor(m_ForeColor,TRUE); InvalidateMyRect(); } }

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void CDrawGraphicsDlg:OnRadioNull() { // TODO: Add your control notification handler code here if (!IsDlgButtonChecked(IDC_CHECK_BORDER)) //无填充时不能也无边框 { CButton *cb=(CButton *)GetDlgItem(IDC_CHECK_BORDER); cb->SetCheck(1); } }

void CDrawGraphicsDlg:OnRadioSloidline() { // TODO: Add your control notification handler code here CString str[9]={\ m_ComboLineValue.ResetContent(); for (int i=0;i<9;i++) m_ComboLineValue.AddString(str[i]); m_ComboLineValue.SetCurSel(3); m_nWidth=4; m_nPenStyle=PS_SOLID; InvalidateMyRect(); }

void CDrawGraphicsDlg:OnRadioDottedline() { // TODO: Add your control notification handler code here for (int i=11;i>0;i--) m_ComboLineValue.DeleteString(i); m_ComboLineValue.SetCurSel(0); m_nWidth=1; m_nPenStyle=PS_DOT; InvalidateMyRect(); }

void CDrawGraphicsDlg:OnCheckBorder() { // TODO: Add your control notification handler code here if (IsDlgButtonChecked(IDC_CHECK_BORDER)) m_nPenStyle=PS_SOLID; else {

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m_nPenStyle=PS_NULL; if (IsDlgButtonChecked(IDC_RADIO_NULL)) //既不能无边框也不能无填充 { CButton *cb=(CButton *)GetDlgItem(IDC_CHECK_BORDER); cb->SetCheck(1); } } }

void CDrawGraphicsDlg:OnRadioClear() { // TODO: Add your control notification handler code here Invalidate(TRUE); }

12、为选择画笔宽度的下拉列表添加CBN_SELCHAGE消息，消息处理函数如下：

void CDrawGraphicsDlg:OnRadioSloidline() { // TODO: Add your control notification handler code here CString str[9]={\ m_ComboLineValue.ResetContent(); for (int i=0;i<9;i++) m_ComboLineValue.AddString(str[i]); m_ComboLineValue.SetCurSel(3); m_nWidth=4; m_nPenStyle=PS_SOLID; InvalidateMyRect(); }

13、为CDrawGraphicsDlg类添加如下的两个自定义函数InvalidateMyRect以及DrawGradient，分别用来刷新工具区和绘制渐变：

void CDrawGraphicsDlg:InvalidateMyRect() //将工具区部分刷新 { CRect invaRect; invaRect.top=0; invaRect.bottom=500; invaRect.left=0; invaRect.right=205;

InvalidateRect(invaRect,TRUE); }

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void CDrawGraphicsDlg:DrawGradient(HDC pDc, const RECT &rect, COLORREF begin, COLORREF end, const int &width)

{ RECT rcstep; //设置每次填充的矩形 HBRUSH br; //创建画刷句柄 int n,m; float step=0.0; int nred=0,ngreen=0,nblue=0; float red=0.0,green=0.0,blue=0.0; nred=(GetRValue(begin)-GetRValue(end)); ngreen=(GetGValue(begin)-GetGValue(end)); nblue=(GetBValue(begin)-GetBValue(end)); step=(float)abs(rect.top-rect.bottom)/(float)width; red=nred/(float)step; green=ngreen/(float)step; blue=nblue/(float)step; for (int start=0;start<=step;start++) //一块快绘制矩形 { n=min((int)(rect.top+start*width),rect.bottom); m=min((int)(rect.top+(start+1)*width),rect.bottom); ::SetRect(&rcstep,rect.left,n,rect.right+1,m); br=CreateSolidBrush(RGB(nred-red*start,ngreen-green*start,nblue-blue*start)); //选择笔刷颜色

HBRUSH oldbr=(HBRUSH)::SelectObject(pDc,br); FillRect(pDc,&rcstep,br);//用新颜色填充矩形区 ::SelectObject(pDc,oldbr); DeleteObject(br); } }

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二、运行结果：

1、 绘图效果：

2、选择颜色对话框以及清空画图板功能：

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