一个在widegets平台上实现的时钟程序

 

在当今IT产业发展两大方向，嵌入式和Web（无线和有线）都离不开跨平台的概念。对于C++程序员来说，Widegets是一个非常好的跨平台的开发库。这里我给大家介绍一个简单的Widgets开发的市中小程序，借此可以对比一下它和MFC的共同点和区别。

 

1.主线程创建的对比

 

  我们知道一般来说，使用MFC的程序员会使用MFC固有的设计模式来实现程序(比如说：视图文档)，所以主线程的实现有系统框架自动生成了，程序简单的情况下不用操心。所以有了CWinApp的基类派生出主线程的类生成全局对象供程序员编写对外的交互，也就是说当Windows调用了WinMain函数的时候，CWinApp的基类派生类的对象被构造，成为了全局对象。

 

  而Widgets对于主线程的实现和MFC很类似，但又有区别。 在概念上和MFC是很相近的，有自己的主线程基类wxApp派生出全局的子类对象和外界交互。具体实现上不太一样。

 

 例如：

 

   MFC的例子

     //H文件子类的定义：class CMyViewerApp : public CWinApp{public:.......//CPP文件//之后会有一个全局对象：CMyViewerApp theApp;  

 

  Widgets的例子

     //H文件class ClockDlgApp : public wxApp{public:bool OnInit();int OnExit();};.......//CPPIMPLEMENT_APP(ClockDlgApp)//告诉Widgets去创建程序的对象

 

2.Dialog对象的创建的对比

   MFC大家很熟悉了，模态对话框是在构造后，使用DoModal创建，非模态对话框使用Create.

   所以这里主要说说Widgets对话框的创建。

    bool ClockDlgApp::OnInit(){ClockDlg* dialog = new ClockDlg(NULL);//set parent wndSetTopWindow(dialog);dialog->Show(true);return true;}

 

3.始终函数的实现

   Widgets使用的绘图函数调用方式和MFC很类似

   void ClockDlg::ClockDlgPaint(wxPaintEvent& event){SetBackgroundStyle(wxBG_STYLE_CUSTOM);//wxPaintDC dc(this);wxBufferedPaintDC dc(this);// Get window dimensionswxSize sz = GetClientSize();wxPoint center = wxPoint(sz.x / 2, sz.y / 2);wxCoord radius = wxMin(sz.x / 2 - 20, sz.y / 2 - 20);radius = wxMax(radius, 50);float factor = wxMax(radius/60.0, 1.0);// create a few colorswxColour lightblue = wxColour(220, 245, 255);wxColour darkblue = wxColour(0, 0, 120);// draw lightblue backgrounddc.SetPen(lightblue);dc.SetBrush(lightblue);dc.DrawRectangle(0, 0, sz.x, sz.y);// draw clock border//draw black borddc.SetPen(*wxBLACK_PEN);dc.SetBrush(*wxBLACK_BRUSH);dc.DrawCircle(center, radius);//draw white backgrounddc.SetPen(*wxBLACK_PEN);dc.SetBrush(*wxBLUE_BRUSH);dc.DrawCircle(center, toInt(radius - 3.0 * factor));PaintOther(center, radius, factor, dc);// paint lines for minutesfloat r_outer = radius - 3 * factor;float r_inner_sec = radius - 5 * factor; float r_inner_min = radius - 7 * factor;float r_inner_hour = radius - 10 * factor;float r_inner_text = radius - 15 * factor;int linewidth = 1;for (int r = 1; r <= 300; r ++){float s = sin(r/300.0*2.0*pi);float c = -cos(r/300.0*2.0*pi);//draw seconds little line linewidth = wxMax(toInt(factor / 4), 1);dc.SetPen(wxPen(*wxWHITE, linewidth));wxPoint outer = wxPoint(toInt(r_outer * s), toInt(r_outer * c));wxPoint inner = wxPoint(toInt(r_inner_sec * s), toInt(r_inner_sec * c));dc.DrawLine(center + inner, center + outer);//draw minutes little lineif(r % 5 == 0){linewidth = wxMax(toInt(factor)/2, 1);dc.SetPen(wxPen(*wxWHITE, linewidth));outer = wxPoint(toInt(r_outer * s), toInt(r_outer * c));inner = wxPoint(toInt(r_inner_min * s), toInt(r_inner_min * c));dc.DrawLine(center + inner, center + outer);}if (r % 25 == 0){linewidth = wxMax(toInt(factor), 1);dc.SetPen(wxPen(*wxWHITE, linewidth));// paint larger lines for the hoursouter = wxPoint(toInt(r_outer * s), toInt(r_outer * c));inner = wxPoint(toInt(r_inner_hour * s), toInt(r_inner_hour * c));dc.DrawLine(center + inner, center + outer);//dc.SetBrush(*wxWHITE_BRUSH);// paint value of the hourwxString hour;hour.Printf("%02d", r / 5);dc.SetFont(wxFont(toInt(5 * factor), wxFONTFAMILY_MODERN, wxFONTSTYLE_NORMAL, wxFONTWEIGHT_BOLD, false, "tahoma", wxFONTENCODING_DEFAULT));// calculate the size of the text and paint it in the windowwxCoord w = 0, h = 0;dc.GetTextExtent(hour, &w, &h);wxPoint text_pos = wxPoint(toInt(r_inner_text * s - w / 2), toInt(r_inner_text * c - h / 2));dc.DrawText(hour, center + text_pos);//dc.DrawRotatedText(hour, center.x + text_pos.x, center.y + text_pos.y, (60-r)/60.0*360); // cool :)}}// draw hour, minute and second hand of the clockwxDateTime time = wxDateTime::Now(); int h = time.GetHour();int m = time.GetMinute();int s = time.GetSecond();int r = 1;/* int h_deg = toInt((h % 12) / 12.0 * 360);int m_deg = toInt(m / 60.0 * 360.0);int s_deg = toInt(s / 60.0 * 360.0);*/float h_rad = (h % 12 + m / 60.0 + s / 3600.0) / 12.0 * 2.0 * pi;float m_rad = (m / 60.0 + s / 3600.0) * 2.0 * pi; float s_rad = s / 60.0 * 2.0 * pi;// show digital time in captionwxString title;title.Printf("Clock %i:%.2i:%.2i", h, m, s);SetTitle(title);//draw hour handr = toInt(factor * 20);linewidth = wxMax(toInt(factor * 5), 1);dc.SetPen(wxPen(*wxLIGHT_GREY, linewidth));dc.DrawLine(center, center + wxPoint(toInt(r * sin(h_rad)), toInt(r * -cos(h_rad))));//draw munite's handr = toInt(factor * 40);linewidth = wxMax(toInt(factor * 2), 1);dc.SetPen(wxPen(*wxLIGHT_GREY, linewidth));dc.DrawLine(center, center + wxPoint(toInt(r * sin(m_rad)), toInt(r * -cos(m_rad))));//draw second's handr = toInt(factor * 50);linewidth = wxMax(toInt(factor), 1);wxColour yello(255, 255, 0);dc.SetPen(wxPen(yello, linewidth));dc.DrawLine(center, center + wxPoint(toInt(r * sin(s_rad)), toInt(r * -cos(s_rad))));r = toInt(factor * 8);dc.SetPen(wxPen(yello, factor));dc.DrawLine(center, center + wxPoint(toInt(r * -sin(s_rad)), toInt(r * cos(s_rad))));//draw little yellow circledc.SetPen(yello);dc.SetBrush(yello);dc.DrawCircle(center, 2 * factor);//// credits for wxWidgets/*dc.SetTextForeground(darkblue);dc.SetFont(wxFont(8, wxFONTFAMILY_MODERN, wxFONTSTYLE_NORMAL, wxFONTWEIGHT_BOLD, false, "arial", wxFONTENCODING_DEFAULT));dc.DrawRotatedText("", toInt(sz.x - 5 - 10), toInt(sz.y - 5), 90);*/}

 

   void ClockDlg::PaintOther(wxPoint center, wxCoord radius, float factor, wxBufferedPaintDC& dc){//wxBufferedPaintDC dc(this);// create a few colorswxColour mywhite = wxColour(255, 255, 255);wxColour myyellow = wxColour(244, 216, 11);wxColour myblack = wxColour(0, 0, 0);wxColour myGray = wxColour(197,192,188);// draw lightblue backgrounddc.SetPen(myyellow);dc.SetBrush(mywhite);dc.DrawRectangle(center.x + radius - 35*factor, center.y - 4*factor, 12*factor, 10*factor);wxDateTime time = wxDateTime::Now(); int date = time.GetDay();int month = time.GetMonth() + 1;int weekday = time.GetWeekDay();int hour = time.GetHour();wxString strDate;strDate.Printf("%d", date);//dc.SetTextForeground(darkblue);dc.SetFont(wxFont(toInt(5 * factor), wxFONTFAMILY_MODERN, wxFONTSTYLE_NORMAL, wxFONTWEIGHT_BOLD, false, "arial", wxFONTENCODING_DEFAULT));dc.DrawRotatedText(strDate, center.x + radius - 34*factor, center.y - 3*factor, 0);wxPoint monthcenter;monthcenter.x = center.x;monthcenter.y = center.y - radius/2.5;dc.SetPen(mywhite);dc.SetBrush(myblack);dc.DrawCircle(monthcenter, radius/4);int linewidth = wxMax(toInt(factor), 1);dc.SetPen(myGray);dc.SetBrush(myGray);dc.DrawCircle(monthcenter, radius/40);float r_inner_month_text = radius/4 - 5 * factor;float r_outer = radius/4;float r_inner_month = radius/4 - 3 * factor; for (int r = 1; r <= 12; r ++){float s = sin(r/12.0*2.0*pi); float c = -cos(r/12.0*2.0*pi);wxString Month;Month.Printf("%02d", r);dc.SetFont(wxFont(toInt(3 * factor), wxFONTFAMILY_MODERN, wxFONTSTYLE_NORMAL, wxFONTWEIGHT_BOLD, false, "tahoma", wxFONTENCODING_DEFAULT));dc.SetTextForeground(myyellow);// calculate the size of the text and paint it in the windowif(r%3 == 0){wxCoord w = 0, h = 0;dc.GetTextExtent(Month, &w, &h);wxPoint text_pos = wxPoint(toInt(r_inner_month_text * s - w / 2), toInt(r_inner_month_text * c - h / 2));dc.DrawText(Month, monthcenter + text_pos); }linewidth = wxMax(toInt(factor / 4), 1);dc.SetPen(wxPen(*wxWHITE, linewidth));wxPoint outer = wxPoint(toInt(r_outer * s), toInt(r_outer * c));wxPoint inner = wxPoint(toInt(r_inner_month * s), toInt(r_inner_month * c));dc.DrawLine(monthcenter + inner, monthcenter + outer);}float month_rad = (month + date / 30.0 ) / 12.0 * 2.0 * pi;int r = toInt(factor * 10);dc.SetPen(wxPen(*wxLIGHT_GREY, linewidth));dc.DrawLine(monthcenter, monthcenter + wxPoint(toInt(r * sin(month_rad)), toInt(r * -cos(month_rad))));wxPoint weekcenter;weekcenter.x = center.x - radius/3.5;weekcenter.y = center.y + radius/3.5;dc.SetPen(*wxBLACK_PEN);dc.SetBrush(mywhite);dc.DrawCircle(weekcenter, radius/4);dc.SetPen(*wxGREY_PEN);dc.SetBrush(*wxBLUE_BRUSH);dc.DrawCircle(weekcenter, radius/6);dc.SetPen(myyellow);dc.SetBrush(myyellow);dc.DrawCircle(weekcenter, radius/45);float r_inner_week_text = radius/6 - 3 * factor;for (int r = 1; r <= 7; r ++){float s = sin(r/7.0*2.0*pi); float c = -cos(r/7.0*2.0*pi);dc.SetFont(wxFont(toInt(2.5 * factor), wxFONTFAMILY_MODERN, wxFONTSTYLE_NORMAL, wxFONTWEIGHT_BOLD, false, "tahoma", wxFONTENCODING_DEFAULT));dc.SetTextForeground(myyellow);wxCoord w = 0, h = 0;if(r == 1){dc.GetTextExtent("M", &w, &h);wxPoint text_pos = wxPoint(toInt(r_inner_week_text * s - w/2 ), toInt(r_inner_week_text * c - h/2));dc.DrawText("M", weekcenter + text_pos); }else if(r == 2){dc.GetTextExtent("T", &w, &h);wxPoint text_pos = wxPoint(toInt(r_inner_week_text * s - w/2 ), toInt(r_inner_week_text * c - h/2));dc.DrawText("T", weekcenter + text_pos); }else if(r == 3){dc.GetTextExtent("W", &w, &h);wxPoint text_pos = wxPoint(toInt(r_inner_week_text * s - w/2 ), toInt(r_inner_week_text * c - h/2));dc.DrawText("W", weekcenter + text_pos); }else if(r == 4){dc.GetTextExtent("T", &w, &h);wxPoint text_pos = wxPoint(toInt(r_inner_week_text * s - w/2 ), toInt(r_inner_week_text * c - h/2));dc.DrawText("T", weekcenter + text_pos); }else if(r == 5){dc.GetTextExtent("F", &w, &h);wxPoint text_pos = wxPoint(toInt(r_inner_week_text * s - w/2 ), toInt(r_inner_week_text * c - h/2));dc.DrawText("F", weekcenter + text_pos); }else if(r == 6){dc.GetTextExtent("S", &w, &h);wxPoint text_pos = wxPoint(toInt(r_inner_week_text * s - w/2 ), toInt(r_inner_week_text * c - h/2));dc.DrawText("S", weekcenter + text_pos); }else if(r == 7){dc.GetTextExtent("S", &w, &h);wxPoint text_pos = wxPoint(toInt(r_inner_week_text * s - w/2 ), toInt(r_inner_week_text * c - h/2));dc.DrawText("S", weekcenter + text_pos); }linewidth = wxMax(toInt(factor / 4), 1);dc.SetPen(wxPen(*wxBLACK, linewidth));wxPoint outer = wxPoint(toInt(r_outer * s), toInt(r_outer * c));wxPoint inner = wxPoint(toInt(r_inner_month * s), toInt(r_inner_month * c));dc.DrawLine(weekcenter + inner, weekcenter + outer);}float week_rad = (weekday + hour / 24.0 ) / 7.0 * 2.0 * pi;r = toInt(factor * 9);dc.SetPen(myyellow);dc.DrawLine(weekcenter, weekcenter + wxPoint(toInt(r * sin(week_rad)), toInt(r * -cos(week_rad))));r = toInt(factor * 4);dc.DrawLine(weekcenter, weekcenter + wxPoint(toInt(r * -sin(week_rad)), toInt(r * cos(week_rad))));}

 

  以上两个函数实现了对于始终面板的描绘。

效果如下图所示：

 

 

 

还有就是Widgets的消息映射机制也和MFC非常相似，有机会大家一起交流。呵呵