修改

Question

我正在做一个Wpf应用程序，我创建一个具有眼睛形状的控件，我在画布中放置一个椭圆（眼睛），我的目的是当鼠标的光标进入画布时椭圆跟随光标鼠标你有什么建议如何执行这项任务？非常感谢你的关注。

干杯

修改

我在Xaml中更新了我的代码：

<Window Height="480" Title="Window2" Width="640" x:Class="WpfApplication5.Window2"
   x:Name="Window" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
   xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
  <Window.Resources>
    <Storyboard x:Key="OnLoaded1">
      <DoubleAnimationUsingKeyFrames Storyboard.TargetName="ctrCircle" 
        Storyboard.TargetProperty="(UIElement.RenderTransform).( TransformGroup.Children)[3].(TranslateTransform.X)">
        <EasingDoubleKeyFrame KeyTime="0:0:0.8" Value="1">
          <EasingDoubleKeyFrame.EasingFunction>
            <ExponentialEase EasingMode="EaseOut" />
          </EasingDoubleKeyFrame.EasingFunction>
      </EasingDoubleKeyFrame>
      </DoubleAnimationUsingKeyFrames>
      <DoubleAnimationUsingKeyFrames Storyboard.TargetName="ctrCircle" 
          Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[3].(TranslateTransform.Y)">
        <EasingDoubleKeyFrame KeyTime="0:0:0.8" Value="1">
        <EasingDoubleKeyFrame.EasingFunction>
            <ExponentialEase EasingMode="EaseOut" />
          </EasingDoubleKeyFrame.EasingFunction>
        </EasingDoubleKeyFrame>
      </DoubleAnimationUsingKeyFrames>
    </Storyboard>
    <Style TargetType="Ellipse">
      <Setter Property="RenderTransform">
        <Setter.Value>
          <ScaleTransform ScaleX="1" ScaleY="1"/>
        </Setter.Value>
      </Setter>
      <Setter Property="RenderTransformOrigin" Value="0.5,0.5"/>
    </Style>
  </Window.Resources>

  <Canvas MouseMove="mov" x:Name="LayoutRoot">
    <Border ackground="Black" B="" Canvas.Left="178" Canvas.Top="103" 
      CornerRadius="250" Height="255.5" Width="290" x:Name="border_eye">
      <Ellipse Fill="#FFFFC600" Height="12" HorizontalAlignment="Left" 
        Margin="0" RenderTransformOrigin="0.5,0.5" Stroke="{x:Null}" 
        VerticalAlignment="Center" Visibility="Visible" Width="12" x:Name="ctrCircle">
        <Ellipse.RenderTransform>
          <TransformGroup>
            <ScaleTransform />
            <SkewTransform />
            <RotateTransform />
            <TranslateTransform />                 
          </TransformGroup>
        </Ellipse.RenderTransform>
      </Ellipse>
    </Border>
  </Canvas>
</Window>

并在后面的代码中：

private void mov(object sender, MouseEventArgs e)
    {
 System.Windows.Point pt = e.GetPosition((Canvas)sender);
      Storyboard invokeStoryboard = this.Resources["OnLoaded1"] as Storyboard;
        ((DoubleAnimationUsingKeyFrames)invokeStoryboard.Children[0]).KeyFrames[0].Value = pt.X;
        ((DoubleAnimationUsingKeyFrames)invokeStoryboard.Children[1]).KeyFrames[0].Value = pt.Y;
        invokeStoryboard.Begin();
    }

现在我的目的是当我在画布区域（LayoutRoot）中移动鼠标时，Ellipse（ctrCircle）仅在Border（border_eye）内部移动并且不会克服“border_eye”的区域这种效果类似于眼睛

您是否有任何输入来完成此步骤？

非常感谢

度过愉快的一天。

干杯

Answer 1

以下是如何使用Rx framework在WPF画布中进行操作的示例。使用Rx而不是附加到鼠标移动事件直接允许您缓冲事件，并且每10毫秒更新一次Pupil位置，从而减少整体CPU负载。

Xaml

<UserControl
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    x:Class="namespace.EyeDemo"
    x:Name="UserControl"
    d:DesignWidth="640" d:DesignHeight="480">

    <Canvas x:Name="LayoutRoot" Background="GreenYellow">
        <Ellipse Fill="Black" Width="120" Height="70" Canvas.Left="90" Canvas.Top="115"/>
        <Ellipse x:Name="Eye" Fill="Black" Width="100" Height="50" Canvas.Left="100" Canvas.Top="125"/>
        <Ellipse x:Name="Pupil" Fill="Red" Height="20" Canvas.Left="139" Canvas.Top="138" Width="20"/>
    </Canvas>
</UserControl>

和背后的代码

/// <summary>
/// Interaction logic for EyeDemo.xaml
/// </summary>
public partial class EyeDemo : UserControl
{
    public EyeDemo()
    {
        this.InitializeComponent();

        double majorRadius = Eye.Width / 2d;
        double minorRadius = Eye.Height / 2d;
        Point center = new Point( Canvas.GetLeft( Eye ) + majorRadius, Canvas.GetTop( Eye ) + minorRadius );

        // create event streams for mouse down/up/move using reflection
        // to keep taking mouse move events and return the X, Y positions
        var mouseMove = from evt in Observable.FromEvent<MouseEventArgs>( LayoutRoot, "PreviewMouseMove" )
                        select (Point?)evt.EventArgs.GetPosition( this );

        // subscribe to the stream of position changes and modify the Canvas.Left and Canvas.Top
        // use the bound by elipse function to restrain the pupil to with the eye.
        mouseMove.BufferWithTime( TimeSpan.FromMilliseconds( 10 ) ).Select( p => BoundByElipse( majorRadius, minorRadius, center, p.LastOrDefault() ) )
            .ObserveOnDispatcher().Subscribe( pos =>
              {
                  if( pos.HasValue )
                  {
                      Canvas.SetLeft( Pupil, pos.Value.X - Pupil.Width / 2d );
                      Canvas.SetTop( Pupil, pos.Value.Y - Pupil.Height / 2d );
                  }
              } );
    }

    private Point? BoundByElipse( double majorRadius, double minorRadius, Point center, Point? point )
    {
        if( point.HasValue )
        {
            // Formular for an elipse is  x^2 / a^2 + y^2 / b^2 = 1
            // where a = majorRadius and b = minorRadius
            // Using this formular we can work out if the point is with in the elipse 
            // or find the boundry point closest to the point

            // Find the location of the point relative to the center.
            Point p = new Point( point.Value.X - center.X, point.Value.Y - center.Y );
            double a = majorRadius;
            double b = minorRadius;

            double f = p.X * p.X / (a * a) + p.Y * p.Y / (b * b);
            if( f <= 1 )
            {
                // the point is with in the elipse;
                return point;
            }
            else
            {
                // the point is outside the elipse, therefore need to find the closest location on the boundry.
                double xdirection = point.Value.X > center.X ? 1 : -1;
                double ydirection = point.Value.X > center.X ? 1 : -1;

                double r = p.X / p.Y;

                double x = p.Y != 0 ? Math.Sqrt( r * r * a * a * b * b / (r * r * b * b + a * a) ) : a;
                double y = r != 0 ? x / r : (point.Value.Y > center.Y ? -b : b);

                return new Point( center.X + xdirection * x, center.Y + ydirection * y );
            }
        }
        else
        {
            return null;
        }
    }
}

Answer 2

使用MouseMove并确保Canvas具有用于命中测试的背景。

XAML：

<Canvas MouseMove="Canvas_MouseMove"
        Background="Transparent">
    <Ellipse x:Name="eye"
             Width="50"
             Height="20"
             Fill="Blue" />
</Canvas>

代码隐藏：

private void Canvas_MouseMove( object sender, System.Windows.Input.MouseEventArgs e )
{
   var pos = e.GetPosition((Canvas)sender);
   Canvas.SetLeft(eye, pos.X);
   Canvas.SetTop(eye, pos.Y);
}

Answer 3

您执行此操作的方式几乎是正确的，但在使用动画后无法修改动画的属性。您必须使用Clone()创建一个新动画并进行修改，删除旧动画，然后应用新修改过的动画。

对象跟随鼠标的光标

修改

3 个答案: