练手WPF（一）——模拟时钟与数字时钟的制作（上）

一、Visual Studio创建一个WPF项目。

简单调整一下MainWindow.xaml文件。主要使用了两个Canvas控件，分别用于显示模拟和数字时钟，命名为AnalogCanvas、digitCanvas。代码如下：

<Window x:Class="MoonClock.MainWindow"
    ...
        Title="Moon Clock" Height="600" Width="1280" WindowStartupLocation="CenterScreen">
    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="*" />
            <ColumnDefinition Width="*" />
        </Grid.ColumnDefinitions>
        <Canvas Grid.Column="0" Name="AnalogCanvs" Width="500" Height="500" />
        <Canvas Grid.Column="1" Name="digitCanvas" Width="600" Height="300" />
    </Grid>
</Window>

二、模拟时钟先来。

（1）在MainWindow.xaml.cs先定义几个字段变量

// 共用字段
DispatcherTimer timer = new DispatcherTimer();  // 计时器
DateTime CurrTime = DateTime.Now;                   // 当前时间

// 模拟时钟字段定义
double radius = ;                              // 圆半径
double angle = ;                               // 角度
Point Opos = new Point();                       // 原点位置
Line HourLine, MinuLine, SecdLine;           // 时针、分针、秒针

这几个变量足够了。

（2）在构造函数初始化变量

public MainWindow()
{
    InitializeComponent();

    // 原点位置
    Opos = new Point(, );

    // 初始化计时器
    timer.Interval = TimeSpan.FromMilliseconds();
    timer.Tick += Timer_Tick;

    // 初始化时钟针
    HourLine = new Line();
    MinuLine = new Line();
    SecdLine = new Line();
}

（3）定义几个画表盘的方法

都是先定义图形，然后添加到AngleCanvas中显示出来

/// <summary>
/// 画表盘外圆
/// </summary>
private void DrawCircle()
{
    Ellipse ellipse = new Ellipse();
    ellipse.Stroke = Brushes.DarkGray;
    ellipse.StrokeThickness = ;
    ellipse.Width = ;
    ellipse.Height = ;
    ellipse.Fill = Brushes.Gray;

    Canvas.SetLeft(ellipse, );
    Canvas.SetTop(ellipse, );

    AnalogCanvs.Children.Add(ellipse);

    Ellipse ellipse1 = new Ellipse();
    ellipse1.Stroke = Brushes.Gray;
    ellipse1.StrokeThickness = ;
    ellipse1.Width = ;
    ellipse1.Height = ;

    Canvas.SetLeft(ellipse1, -);
    Canvas.SetTop(ellipse1, -);
    AnalogCanvs.Children.Add(ellipse1);
}

/// <summary>
/// 圆形表心圆
/// </summary>
private void DrawOCircle()
{
    Ellipse ellipseO = new Ellipse();
    ellipseO.Width = ;
    ellipseO.Height = ;
    ellipseO.Fill = Brushes.DarkGray;

    Canvas.SetLeft(ellipseO, Opos.X - );
    Canvas.SetTop(ellipseO, Opos.Y - );

    if (AnalogCanvs.Children.Contains(ellipseO))
        AnalogCanvs.Children.Remove(ellipseO);
    AnalogCanvs.Children.Add(ellipseO);
}

/// <summary>
/// 画圆表盘数字
/// </summary>
 private void DrawDigit()
{
     double x, y;
     for (int i=; i<; i++)
     {
          angle = WrapAngle(i * 360.0 / 12.0) - 90.0;
          angle = ConvertDegreesToRadians(angle);

          x = Opos.X + Math.Cos(angle) * (radius - ) - ;
          y = Opos.Y + Math.Sin(angle) * (radius - ) - ;

          TextBlock digit = new TextBlock();
          digit.FontSize = ;
          digit.Text = i.ToString();

          // 数字12位置校正
          if (i == )
          {
               Canvas.SetLeft(digit, x - );
          }
          else
          {
              Canvas.SetLeft(digit, x);
          }
          Canvas.SetTop(digit, y);
          AnalogCanvs.Children.Add(digit);
     }
}

这里ConvertDegreesToRadians方法后面再定义，用于将角度值转换为弧度。

继续画：

/// <summary>
/// 画圆表刻度
/// </summary>
private void DrawGridLine()
{
    double x1 = , y1 = ;
    double x2 = , y2 = ;

    for (int i = ; i < ; i++)
    {
        double angle1 = WrapAngle(i * 360.0 / 60.0) - ;
        angle1 = ConvertDegreesToRadians(angle1);

        if (i %  == )
        {
            x1 = Math.Cos(angle1) * (radius - );
            y1 = Math.Sin(angle1) * (radius - );
        }
        else
        {
            x1 = Math.Cos(angle1) * (radius - );
            y1 = Math.Sin(angle1) * (radius - );
        }

        x2 = Math.Cos(angle1) * (radius - );
        y2 = Math.Sin(angle1) * (radius - );

        Line line = new Line();
        line.X1 = x1;
        line.Y1 = y1;
        line.X2 = x2;
        line.Y2 = y2;
        line.Stroke = Brushes.Black;
        line.StrokeThickness = ;

        Canvas.SetLeft(line, Opos.X);
        Canvas.SetTop(line, Opos.Y);
        AnalogCanvs.Children.Add(line);

    }
}

以上两个画刻度和画表盘数字方法原理是一样的，就是先计算角度，再与半径计算为位置，之后将刻度或数字图形画到AngleCanvas中。

（4）是时候画时针了。

先来短黑粗的小时针

/// <summary>
/// 画时针
/// </summary>
private void DrawHourLine()
{
    int hour = CurrTime.Hour;
    int minu = CurrTime.Minute;
    double dminu = minu / 60.0;         // 根据分钟数增加时针偏移
    double dhour = hour + dminu;

    double hour_angle = WrapAngle(dhour * (360.0 / 12.0) - 90.0);
    hour_angle = ConvertDegreesToRadians(hour_angle);

    double x = Math.Cos(hour_angle) * (radius - );
    double y = Math.Sin(hour_angle) * (radius - );

    HourLine.X1 = ;
    HourLine.Y1 = ;
    HourLine.X2 = x;
    HourLine.Y2 = y;
    HourLine.Stroke = Brushes.Black;
    HourLine.StrokeThickness = ;

    Canvas.SetLeft(HourLine, Opos.X);
    Canvas.SetTop(HourLine, Opos.Y);
    if(AnalogCanvs.Children.Contains(HourLine))
    {
        AnalogCanvs.Children.Remove(HourLine);
    }
    AnalogCanvs.Children.Add(HourLine);
}

其中注释句用于根据分钟数增加小时指针的偏移。如果没有增加这一偏移，会是每小时跳一次小时指针，现实中的模拟时钟是不存在这种情况的。

再来秒钟指针：

/// <summary>
/// 画秒针
/// </summary>
private void DrawSecondLine()
{
    int second = CurrTime.Second;

    // 秒针正方向点
    double se_angle = WrapAngle(second * (360.0 / 60.0) - );
    se_angle = ConvertDegreesToRadians(se_angle);
    double sec_x = Math.Cos(se_angle) * (radius - );
    double sec_y = Math.Sin(se_angle) * (radius - );

    // 秒针反方向点
    se_angle = WrapAngle(second * (360.0 / 60.0) + );
    se_angle = ConvertDegreesToRadians(se_angle);
    double sec_x_ = Math.Cos(se_angle) * (radius - );
    double sec_y_ = Math.Sin(se_angle) * (radius - );

    SecdLine.X1 = sec_x_;
    SecdLine.Y1 = sec_y_;
    SecdLine.X2 = sec_x;
    SecdLine.Y2 = sec_y;
    SecdLine.Stroke = Brushes.Red;
    SecdLine.StrokeThickness = ;

    Canvas.SetLeft(SecdLine, Opos.X);
    Canvas.SetTop(SecdLine, Opos.Y);
    if (AnalogCanvs.Children.Contains(SecdLine))
    {
        AnalogCanvs.Children.Remove(SecdLine);
    }
    AnalogCanvs.Children.Add(SecdLine);
}

反方向点用于确定秒钟指针经过原点另一端的位置。一般秒钟在圆点两端都会伸出，只是两端长短不同而已。

分钟就留给有心人练手吧，这里就不贴了。

（5）接近最后——两个辅助方法

/// <summary>
/// 角度360度进制
/// </summary>
/// <param name="angle"></param>
/// <returns></returns>
private double WrapAngle(double angle)
{
    return angle % ;
}

/// <summary>
/// 将角度转为弧度
/// </summary>
/// <param name="degrees"></param>
/// <returns></returns>
private double ConvertDegreesToRadians(double degrees)
{
    double radians = (Math.PI / ) * degrees;

    return radians;
}

（6）更新方法：方法中的几项内容是需要根据时间更新的。

/// <summary>
/// 更新小时针、分针、秒针
/// </summary>
private void Update()
{
    DrawHourLine();
    DrawMinuteLine();
    DrawSecondLine();
    DrawOCircle();
}

（7）定义计时器事件

/// <summary>
/// 计时器事件
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void Timer_Tick(object sender, EventArgs e)
{
    // 更新当前时间
    CurrTime = DateTime.Now;
// 更新圆盘时针
    Update();
}

看最后效果