WPF - 椭圆几何图形动画在 C# 中使用情节提要

Question

我需要用 ScaleTransform 在 C# 中缩放椭圆几何，但它不起作用。代码如下：

XAML：

<Image x:Name="rock" Stretch="None">
    <Image.Clip>
        <EllipseGeometry x:Name="rockClip" RadiusX="100" RadiusY="100" Center="200,150">
            <EllipseGeometry.Transform>
                    <ScaleTransform/>
            </EllipseGeometry.Transform>
        </EllipseGeometry>
    </Image.Clip>
</Image>

C#：

DoubleAnimation scaleX = new DoubleAnimation();
scaleX.BeginTime = TimeSpan.FromMilliseconds(fromMills);
scaleX.Duration = new Duration(TimeSpan.FromMilliseconds(2000));
scaleX.From = 0.0;
scaleX.To = 1.0;
scaleX.SetValue(Storyboard.TargetProperty, rockClip);
scaleX.SetValue(Storyboard.TargetPropertyProperty, new PropertyPath("(EllipseGeometry.Transform).(ScaleTransform.ScaleX)"));
DoubleAnimation scaleY = new DoubleAnimation();
scaleY.BeginTime = TimeSpan.FromMilliseconds(fromMills);
scaleY.Duration = new Duration(TimeSpan.FromMilliseconds(2000));
scaleY.From = 0.0;
scaleY.To = 1.0;
scaleY.SetValue(Storyboard.TargetProperty, rockClip);
scaleY.SetValue(Storyboard.TargetPropertyProperty, new PropertyPath("(EllipseGeometry.Transform).(ScaleTransform.ScaleY)"));
Storyboard storyboard = new Storyboard();
storyboard.Children.Add(scaleX);
storyboard.Children.Add(scaleY);
storyboard.Completed += storyboard_Completed;
animation.Begin();

storyboard_Completed事件被触发，但椭圆几何体上没有动画。

问题出在哪里？

我只能以这种方式对椭圆几何图形进行动画处理：

DoubleAnimation scale = new DoubleAnimation();
scale.From = 0;
scale.To = 40;
scale.Duration = new Duration(TimeSpan.FromMilliseconds(5000));
rockClip.BeginAnimation(EllipseGeometry.RadiusXProperty, scale);
rockClip.BeginAnimation(EllipseGeometry.RadiusYProperty, scale);

我需要把这个双动画放在故事板中，但我不知道怎么做。

谢谢。

Answer 1

如果使用图像控件（而不是几何图形）作为目标元素，则它有效：

var scaleX = new DoubleAnimation();
scaleX.BeginTime = TimeSpan.FromMilliseconds(fromMills);
scaleX.Duration = TimeSpan.FromSeconds(2);
scaleX.From = 0.0;
scaleX.To = 1.0;
Storyboard.SetTarget(scaleX, rock);
Storyboard.SetTargetProperty(scaleX, new PropertyPath("Clip.Transform.ScaleX"));
var scaleY = new DoubleAnimation();
scaleY.BeginTime = TimeSpan.FromMilliseconds(fromMills);
scaleY.Duration = TimeSpan.FromSeconds(2);
scaleY.From = 0.0;
scaleY.To = 1.0;
Storyboard.SetTarget(scaleY, rock);
Storyboard.SetTargetProperty(scaleY, new PropertyPath("Clip.Transform.ScaleY"));
var storyboard = new Storyboard();
storyboard.Children.Add(scaleX);
storyboard.Children.Add(scaleY);
storyboard.Begin();

---

但是，最简单的方法可能是命名 ScaleTransform。

<EllipseGeometry.Transform>
    <ScaleTransform x:Name="scale"/>
</EllipseGeometry.Transform>

并像这样运行动画：

var scaleAnimation = new DoubleAnimation
{
    BeginTime = TimeSpan.FromMilliseconds(fromMills),
    Duration = TimeSpan.FromSeconds(2),
    From = 0.0,
    To = 1.0
};
scale.BeginAnimation(ScaleTransform.ScaleXProperty, scaleAnimation);
scale.BeginAnimation(ScaleTransform.ScaleYProperty, scaleAnimation);

---

编辑：为了通过情节提要对RadiusX和RadiusY属性进行动画处理，您可以编写以下内容：

var radiusXAnimation = new DoubleAnimation();
radiusXAnimation.BeginTime = TimeSpan.FromMilliseconds(fromMills);
radiusXAnimation.Duration = TimeSpan.FromSeconds(2);
radiusXAnimation.From = 0;
radiusXAnimation.To = 100;
Storyboard.SetTarget(radiusXAnimation, rock);
Storyboard.SetTargetProperty(radiusXAnimation, new PropertyPath("Clip.RadiusX"));
var radiusYAnimation = new DoubleAnimation();
radiusYAnimation.BeginTime = TimeSpan.FromMilliseconds(fromMills);
radiusYAnimation.Duration = TimeSpan.FromSeconds(2);
radiusYAnimation.From = 0;
radiusYAnimation.To = 100;
Storyboard.SetTarget(radiusYAnimation, rock);
Storyboard.SetTargetProperty(radiusYAnimation, new PropertyPath("Clip.RadiusY"));
var storyboard = new Storyboard();
storyboard.Children.Add(radiusXAnimation);
storyboard.Children.Add(radiusYAnimation);
storyboard.Begin();