使用 RotateTransform 从中心旋转 DrawingBrush

Question

我有一个我希望旋转的指南针的 UserControl。我试图从中心旋转它，并且 Google 找到了大量关于使用 RenderTransformOrigin="0.5,0.5" 实现此目的的参考。但由于某种原因，这不起作用。它只是以角为原点旋转 UserControl。

如果我在 UserControl 中设置 CenterX="150" 和 CenterY="150"，它就可以工作。但是后来我还必须将主要window中UserControl的高度和宽度设置为300。

无论调用 UserControl 时设置的高度和宽度设置如何，如何使 UserControl 从其中心点旋转？我也更愿意在 UserControl 中设置 RenderTransformOrigin 而不是在调用它时。

（简化）用户控件 XAML:

<UserControl x:Class="Poseidon.Views.CompassUserControl"
             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" 
             xmlns:local="clr-namespace:Poseidon.Views"
             mc:Ignorable="d" 
             d:DesignHeight="300" d:DesignWidth="300">

    <Grid>
        <Grid.Resources>
            <DrawingBrush x:Key="Compass_ver1">
                <DrawingBrush.Drawing>
                    <DrawingGroup>
                        <DrawingGroup.Children>
                            <GeometryDrawing Brush="#FF000000" Geometry="M 375.286,151.366C 486.487,151.366 576.634,241.513 576.634,352.714C 576.634,463.915 486.487,554.061 375.286,554.061C 264.085,554.061 173.939,463.915 173.939,352.714C 173.939,241.513 264.085,151.366 375.286,151.366 Z "/>
                            <GeometryDrawing Geometry="M 375.286,151.366C 486.487,151.366 576.634,241.513 576.634,352.714C 576.634,463.915 486.487,554.061 375.286,554.061C 264.085,554.061 173.939,463.915 173.939,352.714C 173.939,241.513 264.085,151.366 375.286,151.366 Z ">
                                <GeometryDrawing.Pen>
                                    <Pen Thickness="0.755907" LineJoin="Round" Brush="#FF000000"/>
                                </GeometryDrawing.Pen>
                            </GeometryDrawing>
                            <GeometryDrawing Brush="#FFFFFFFF" Geometry="M 382.484,188.872C 472.971,192.847 543.103,269.425 539.128,359.912C 535.153,450.399 458.575,520.531 368.088,516.556C 277.601,512.58 207.469,436.003 211.444,345.516C 215.42,255.029 291.997,184.897 382.484,188.872 Z "/>
                            <GeometryDrawing Geometry="M 382.484,188.872C 472.971,192.847 543.103,269.425 539.128,359.912C 535.153,450.399 458.575,520.531 368.088,516.556C 277.601,512.58 207.469,436.003 211.444,345.516C 215.42,255.029 291.997,184.897 382.484,188.872 Z ">
                                <GeometryDrawing.Pen>
                                    <Pen Thickness="0.755907" LineJoin="Round" Brush="#FF000000"/>
                                </GeometryDrawing.Pen>
                            </GeometryDrawing>
                            <GeometryDrawing Brush="#FF000000" Geometry="M 375.286,227.352L 389.511,202.805L 403.736,178.258L 375.286,178.258L 346.836,178.258L 361.061,202.805L 375.286,227.352 Z "/>
                            <GeometryDrawing Geometry="M 375.286,227.352L 389.511,202.805L 403.736,178.258L 375.286,178.258L 346.836,178.258L 361.061,202.805L 375.286,227.352 Z ">
                                <GeometryDrawing.Pen>
                                    <Pen Thickness="0.755907" LineJoin="Round" Brush="#FF000000"/>
                                </GeometryDrawing.Pen>
                            </GeometryDrawing>
                        </DrawingGroup.Children>
                    </DrawingGroup>
                </DrawingBrush.Drawing>
            </DrawingBrush>
        </Grid.Resources>
        <Rectangle Fill="{StaticResource Compass_ver1}">
            <Rectangle.RenderTransform>
                <RotateTransform Angle="{Binding FlightData.Value.Heading}" />
            </Rectangle.RenderTransform>
        </Rectangle>
    </Grid>
</UserControl>

主要windowXAML:

<local:CompassUserControl DataContext="{Binding Rov}" Height="100" Width="100" RenderTransformOrigin="0.5,0.5"/>

Answer 1

RenderTransformOrigin 属性获取或设置 RenderTransform 属性声明的任何变换的中心点，相对于您应用的元素的边界变换：https://msdn.microsoft.com/en-us/library/system.windows.uielement.rendertransformorigin(v=vs.110).aspx

所以-正如@Maxim 所建议的-您应该在 UserControl:

中设置 Rectangle 元素的 RenderTransformOrigin 属性

<Rectangle Fill="{StaticResource Compass_ver1}" RenderTransformOrigin="0.5, 0.5">
    <Rectangle.RenderTransform>
        <RotateTransform Angle="{Binding FlightData.Value.Heading}" />
    </Rectangle.RenderTransform>
</Rectangle>

使用 RotateTransform 从中心旋转 DrawingBrush

Rotating DrawingBrush from center using RotateTransform

c#

wpf

xaml

user-controls