MatrixTransform 内部的 MatrixTransform 行为不是我所期望的

Question

我目前有一个绑定到 MatrixTransform 的 Border。当滚动鼠标滚轮时，它基本上会缩放 MatrixTransform。在边框内部，我有一个水平和垂直居中的矩形。当缩放边框变换时，我将矩形的变换设置为等于边框的反转。 ides 是为了保持矩形大小相同并且位于中心。我当前的解决方案将使矩形保持相同的大小，但随着您不断缩放，它会逐渐远离中心。似乎矩形变换不知道边框变换，这有意义吗？

这是几张图像，第一张是初始图像，第二张是缩放几次后的图像（请注意，矩形保持相同大小，但不再居中）。

我试图解决的基本想法就像谷歌地图应用程序一样，当你放大时，城市名称大小保持不变。

这是我的所有代码，如果您愿意，您应该能够将其拉入并运行它：

MainPage.xaml

<UserControl x:Class="InvertedZoomTest.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:InvertedZoomTest"
mc:Ignorable="d">

<UserControl.DataContext>
    <local:MainPage_ViewModel/>
</UserControl.DataContext>

<Border BorderBrush="Pink" Background="Gray" VerticalAlignment="Center" HorizontalAlignment="Center"  BorderThickness="2" MouseWheel="Border_MouseWheel" Height="100" Width="100" RenderTransform="{Binding MainTransform}">
    <Rectangle x:Name="rectangle" Canvas.Top="43" Canvas.Left="43" Fill="Red" Height="10" Width="10" HorizontalAlignment="Center" VerticalAlignment="Center" RenderTransform="{Binding TextTransform}"/>
</Border>

MainPage.xaml.cs

public partial class MainPage : UserControl
{
    public MainPage()
    {
        InitializeComponent();
    }

    private MainPage_ViewModel viewModel
    {
        get
        {
            return this.DataContext as MainPage_ViewModel;
        }
    }

    private void Border_MouseWheel(object sender, MouseWheelEventArgs e)
    {
        if (e.Delta > 0)
        {
            this.viewModel.ZoomRatio += .1;
        }
        else
        {
            this.viewModel.ZoomRatio -= .1;
        }

        this.viewModel.UpdateTextScale();
    }
}

MainPage_ViewModel.cs

public class MainPage_ViewModel : INotifyPropertyChanged
{
    public MatrixTransform TextTransform
    {
        get { return _textTransform; }
        set
        {
            if (value != _textTransform)
            {
                _textTransform = value;
                OnPropertyChanged("TextTransform");
            }
        }
    }
    private MatrixTransform _textTransform = new MatrixTransform();

    public MatrixTransform MainTransform
    {
        get
        {
            return _mainTransform;
        }
        set
        {
            if (value != _mainTransform)
            {
                _mainTransform = value;
                OnPropertyChanged("MainTransform");
            }
        }
    }
    private MatrixTransform _mainTransform = new MatrixTransform();

    public void UpdateTextScale()
    {
        var scaleX = (double)(ZoomRatio);
        var scaleY = (double)(ZoomRatio);

        Matrix updatedMainTransformMatrix = new Matrix(scaleX, 0, 0, scaleY, 0, 0);
        this.MainTransform.Matrix = updatedMainTransformMatrix;
        OnPropertyChanged("MainTransform");

        this.TextTransform = MainTransform.Inverse as MatrixTransform;
        OnPropertyChanged("TextTransform");
    }

    public double ZoomRatio
    {
        get
        {
            return zoomRatio;
        }
        set
        {
            zoomRatio = value;
            OnPropertyChanged("ZoomRatio");

            UpdateTextScale();
        }
    }
    private double zoomRatio = 1;


    public event PropertyChangedEventHandler PropertyChanged;

    public void OnPropertyChanged(string propertyName)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

我做错了什么会使这个矩形从中心移动吗？任何帮助将不胜感激！

更新 出于好奇，我在矩形周围包裹了一个边框，并在宽度和宽度上进行了元素到元素的绑定。高度。您会在下图中注意到矩形上的变换似乎在左上角有一个原点，这有意义吗？

新的 XAML：

<Border BorderBrush="Pink" Background="Gray" VerticalAlignment="Center" HorizontalAlignment="Center"  BorderThickness="2" MouseWheel="Border_MouseWheel" Height="100" Width="100" RenderTransform="{Binding MainTransform}">
    <Border BorderBrush="Green" BorderThickness="1" Height="{Binding ElementName=rectangle, Path=Height}" Width="{Binding ElementName=rectangle, Path=Width}">
        <Rectangle x:Name="rectangle" Canvas.Top="43" Canvas.Left="43" Fill="Red" Height="10" Width="10" HorizontalAlignment="Center" VerticalAlignment="Center" RenderTransform="{Binding TextTransform}"/>
    </Border>
</Border>

结果图像：

Answer 1

我明白了这一点。我只需要将矩形的 RenderTransformOrigin 设置为中心。

<Border BorderBrush="Pink" Background="Gray" VerticalAlignment="Center" HorizontalAlignment="Center"  BorderThickness="2" MouseWheel="Border_MouseWheel" Height="100" Width="100" RenderTransform="{Binding MainTransform}"> 
<Border BorderBrush="Green" BorderThickness="1" Height="{Binding ElementName=rectangle, Path=Height}" Width="{Binding ElementName=rectangle, Path=Width}"> 
    <Rectangle x:Name="rectangle" Canvas.Top="43" Canvas.Left="43" Fill="Red" Height="10" Width="10" HorizontalAlignment="Center" VerticalAlignment="Center" RenderTransform="{Binding TextTransform}" RenderTransformOrigin=".5,.5"/> 
</Border>