WPF:在角度动画之前更改RotateTransform中心

Question

我尝试为我的用户控件做一个简单的旋转动画.当控件获得键盘焦点时,将触发此动画.我希望它围绕它的中心旋转.

问题是,我在加载动画的控件左下角设置了原始中心点.因此,为了纠正这个问题,我将中心设置在触发器IsFocused的控件中间.

但我的GetKeyboardFocus动画保留了原始中心.

触发器是在eventtrigger之后执行的吗？或者我做错了什么.

<UserControl x:Class="testtuile.rectangle"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
         mc:Ignorable="d" 
         d:DesignHeight="300" d:DesignWidth="300" Height="150" Width="300" Padding="4" Focusable="True" MouseDown="UserControl_MouseDown" IsTabStop="True">
<UserControl.RenderTransform>
    <RotateTransform Angle="0" CenterX="0" CenterY="150"></RotateTransform>
</UserControl.RenderTransform>
<UserControl.Style>
    <Style>
        <Style.Triggers>
            <Trigger Property="Control.IsFocused" Value="True">
                <Setter Property="Control.BorderBrush" Value="Gold"></Setter>
                <Setter Property="Control.BorderThickness" Value="2"></Setter>
                <Setter Property="Control.RenderTransform">
                    <Setter.Value>
                        <RotateTransform CenterX="150" CenterY="75"/>
                    </Setter.Value>
                </Setter>
            </Trigger>
        </Style.Triggers>
    </Style>
</UserControl.Style>
<UserControl.Triggers>
    <EventTrigger RoutedEvent="Loaded">
        <EventTrigger.Actions>
            <BeginStoryboard>
                <Storyboard>
                    <DoubleAnimation
                        Storyboard.TargetProperty="(RenderTransform).(RotateTransform.Angle)"
                        From="90" To="0" Duration="0:0:0.8" 
                        AutoReverse="False" 
                    />
                    <DoubleAnimation
                        Storyboard.TargetProperty="Opacity"
                        From="0" Duration="0:0:0.6"
                        AutoReverse="False"
                    />
                </Storyboard>
            </BeginStoryboard>
        </EventTrigger.Actions>
    </EventTrigger>
    <EventTrigger RoutedEvent="GotKeyboardFocus">
        <EventTrigger.Actions>
            <BeginStoryboard Name="ButtonFocusedAnimation">
                <Storyboard>

                    <DoubleAnimation
                        Storyboard.TargetProperty="(RenderTransform).(RotateTransform.Angle)"
                        From="-2" To="2" Duration="0:0:1" 
                        AutoReverse="True" RepeatBehavior="Forever" 
                    />
                </Storyboard>
            </BeginStoryboard>
        </EventTrigger.Actions>
    </EventTrigger>
    <EventTrigger RoutedEvent="LostKeyboardFocus">
        <StopStoryboard BeginStoryboardName="ButtonFocusedAnimation" />
    </EventTrigger>
</UserControl.Triggers>

<Grid Background="Aquamarine">


</Grid>

谢谢您的帮助.

Answer 1

您不必在动画之前更改它.要旋转圆形中心点设置UIElement.RenderTransformOrigin为UserControl:

<UserControl RenderTransformOrigin="0.5,0.5" ...>

获取或设置RenderTransform声明的任何可能的渲染变换的中心点,相对于元素的边界

然后

RenderTransformOrigin对Point结构值的使用有些不规范,因为Point不表示坐标系中的绝对位置.相反,0到1之间的值被解释为每个x,y轴中当前元素范围的因子.例如,(0.5,0.5)将使渲染变换在元素上居中,或者(1,1)将渲染变换放在元素的右下角