.net-4.0 - 为 SolidColorBrush 设置动画时遇到问题

Question

我有以下代码：

<Grid.Background>
                <DrawingBrush Stretch="Uniform">
                    <DrawingBrush.Drawing>
                        <DrawingGroup>
                            <GeometryDrawing Brush="{Binding Path=SegmentBackground, ElementName=Segment, Mode=OneWay}" x:Name="SegmentDrawing" Geometry="M 278.229,141.688C 278.229,128.798 276.451,116.324 273.128,104.497L 228.906,122.309C 230.417,128.8 231.216,135.565 231.216,142.517C 231.216,147.98 230.723,153.328 229.778,158.518L 275.262,170.2C 277.206,161.002 278.229,151.464 278.229,141.688 Z ">
                                <GeometryDrawing.Pen>
                                    <Pen LineJoin="Round" Brush="#FF000000"/>
                                </GeometryDrawing.Pen>
                            </GeometryDrawing>
                        </DrawingGroup>
                    </DrawingBrush.Drawing>
                </DrawingBrush>
            </Grid.Background>

我的问题很简单，我想为 GeometryDrawingBrush 的 Brush 属性设置动画。绘图是我的控件的主要视觉效果，我希望画笔的颜色发生变化以反映它的状态（正常、过度等）。