WPF实现烟花效果，有谁能提供思路吗

Question

WPF怎么实现效果，怎么使用WPF实现这样的一个烟花效果呢，麻烦告知下。谢谢。

Answer 1

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在WPF中创建烟花效果可以通过使用Storyboard、Path和DoubleAnimationUsingKeyFrames等控件和动画来实现。下面是一个简单的步骤指南和示例代码，用于创建一个基本的烟花绽放效果。你可以根据需求进行调整和优化。

首先，我们需要创建一个XAML文件（例如：MainWindow.xaml）并定义一个Grid作为根容器：

<Window x:Class="Fireworks.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="Fireworks" Height="800" Width="1200">
    <Grid>
        <!-- Firework effects will be added here -->
    </Grid>
</Window>

接下来，在App.xaml.cs中设置窗口的背景为黑色，这样烟花效果更明显：

using System.Windows;

namespace Fireworks
{
    public partial class App : Application
    {
        protected override void OnStartup(StartupEventArgs e)
        {
            base.OnStartup(e);
            MainWindow mainWindow = new MainWindow();
            mainWindow.Background = Brushes.Black;
            mainWindow.Show();
        }
    }
}

然后，我们在MainWindow.xaml中添加一个按钮，点击后启动烟花效果：

<Button Content="Start Fireworks" Click="Button_Click" HorizontalAlignment="Center" VerticalAlignment="Center"/>

在MainWindow.xaml.cs中编写按钮点击事件处理程序，创建烟花效果：

using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Shapes;

namespace Fireworks
{
    public partial class MainWindow : Window
    {
        private List<Path> fireworks = new List<Path>();

        public MainWindow()
        {
            InitializeComponent();
        }

        private async void Button_Click(object sender, RoutedEventArgs e)
        {
            for (int i = 0; i < 50; i++)
            {
                // 创建一个新的烟花路径
                Path firework = CreateFirework();
                fireworks.Add(firework);

                // 将烟花添加到网格中
                Grid.SetZIndex(firework, fireworks.Count); // 设置层叠顺序
                this.ContentPanel.Children.Add(firework);

                // 开始烟花动画
                await AnimateFirework(firework);
            }
        }

        private Path CreateFirework()
        {
            // 创建一个椭圆形状作为烟花
            PathGeometry geometry = new PathGeometry();
            var figure = new PathFigure();
            figure.StartPoint = new Point(0, 0);
            figure.Segments.Add(new LineSegment(new Point(10, 10), true));
            geometry.Figures.Add(figure);

            Path path = new Path();
            path.Data = geometry;
            path.Stroke = Brushes.White;
            path.StrokeThickness = 2;
            path.Fill = Brushes.Red;
            return path;
        }

        private async Task AnimateFirework(Path firework)
        {
            // 烟花绽放动画
            Storyboard storyboard = new Storyboard();

            DoubleAnimationUsingKeyFrames scaleAnimation = new DoubleAnimationUsingKeyFrames();
            EasingDoubleKeyFrame startFrame = new EasingDoubleKeyFrame { KeyTime = KeyTime.FromTimeSpan(TimeSpan.Zero), Value = 1 };
            EasingDoubleKeyFrame endFrame = new EasingDoubleKeyFrame { KeyTime = KeyTime.FromTimeSpan(TimeSpan.FromSeconds(1)), Value = 3 };
            scaleAnimation.KeyFrames.Add(startFrame);
            scaleAnimation.KeyFrames.Add(endFrame);
            Storyboard.SetTarget(scaleAnimation, firework);
            Storyboard.SetTargetProperty(scaleAnimation, new PropertyPath("(UIElement.RenderTransform).(ScaleTransform.ScaleX)"));
            storyboard.Children.Add(scaleAnimation);

            DoubleAnimationUsingKeyFrames rotateAnimation = new DoubleAnimationUsingKeyFrames();
            EasingDoubleKeyFrame startRotationFrame = new EasingDoubleKeyFrame { KeyTime = KeyTime.FromTimeSpan(TimeSpan.Zero), Value = 0 };
            EasingDoubleKeyFrame endRotationFrame = new EasingDoubleKeyFrame { KeyTime = KeyTime.FromTimeSpan(TimeSpan.FromSeconds(1)), Value = Math.PI * 2 };
            rotateAnimation.KeyFrames.Add(startRotationFrame);
            rotateAnimation.KeyFrames.Add(endRotationFrame);
            Storyboard.SetTarget(rotateAnimation, firework);
            Storyboard.SetTargetProperty(rotateAnimation, new PropertyPath("(UIElement.RenderTransform).(RotateTransform.Angle)"));
            storyboard.Children.Add(rotateAnimation);

            // 烟火移动动画
            TranslateTransform transform = new TranslateTransform();
            firework.RenderTransform = transform;
            DoubleAnimation positionAnimation = new DoubleAnimation();
            positionAnimation.From = new Random().NextDouble() * this.Width;
            positionAnimation.To = this.Width + 100;
            positionAnimation.Duration = TimeSpan.FromSeconds(2);
            Storyboard.SetTarget(positionAnimation, firework);
            Storyboard.SetTargetProperty(positionAnimation, new PropertyPath("(UIElement.RenderTransform).(TranslateTransform.X)"));
            storyboard.Children.Add(positionAnimation);

            // 结束动画后删除烟火
            storyboard.Completed += (_, __) => fireworks.Remove(firework);
            storyboard.Begin();
        }
    }
}

这个例子中的烟花效果非常基础，仅包含一个简单的爆炸和移动动画。你可以通过增加更多的形状、颜色变化、速度变化以及随机性来增强效果。如果你想要更复杂的烟花效果，可能需要使用粒子系统库，如AvaloniaFX的ParticleSystem，或者考虑使用GPU加速的库，如SharpDX。