TranslateTransform cancels ScaleTransform

本文关键字：ScaleTransform cancels TranslateTransform | 更新日期: 2023-09-27 17:50:50

我是WPF的新手，经过相当多的玩，我终于得到了我的控制安排的方式，我想在我正在工作的项目。我有一个显示图像的矩形。鼠标滚轮用ScaleTransform动画缩放图像，鼠标点击/拖动在屏幕上移动图像。问题是，如果我将图像向上或向下缩放，然后尝试移动它，它会自动将自己缩放回1(原始大小)。当它缩放时有没有办法移动它呢?编辑:我尝试将ScaleTransform和TranslateTransform设置为TransformGroup，但仍然不起作用。

我遇到的另一个问题是，如果图像大于父容器，它超出了界限，我尝试在父容器上设置ClipToBounds = True，但它不起作用。

代码:

private void Window_MouseWheel_1(object sender, MouseWheelEventArgs e)
{
    if (e.Delta > 0)
    {
        ScaleTransform scaleP = new ScaleTransform();
        scaleP.CenterX = e.GetPosition(this).X;
        scaleP.CenterY = e.GetPosition(this).Y;
        rect.RenderTransform = scaleP;
        DoubleAnimation dblAnimX = new DoubleAnimation();
        dblAnimX.From = scaleXFrom;
        dblAnimX.To = scaleXTo + 0.1;
        scaleXFrom = scaleXTo +0.1;
        scaleXTo += 0.1;
        Duration = new Duration(TimeSpan.FromSeconds(0.15));
        DoubleAnimation dblAnimY = new DoubleAnimation();
        dblAnimY.From = scaleYFrom;
        dblAnimY.To = scaleYTo + 0.1;
        scaleYFrom = scaleYTo +0.1;
        scaleYTo += 0.1;
        Duration = new Duration(TimeSpan.FromSeconds(0.15));
        scaleP.BeginAnimation(ScaleTransform.ScaleXProperty, dblAnimX);
        scaleP.BeginAnimation(ScaleTransform.ScaleYProperty, dblAnimY);
    }
    else
    {
        ScaleTransform scaleM = new ScaleTransform();
        scaleM.CenterX = e.GetPosition(this).X;
        scaleM.CenterY = e.GetPosition(this).Y;
        rect.RenderTransform = scaleM;                           
        DoubleAnimation dblAnimX = new DoubleAnimation();
        dblAnimX.From = scaleXFrom;
        dblAnimX.To = scaleXTo -0.1;
        scaleXFrom = scaleXTo -0.1;
        scaleXTo -= 0.1;
        dblAnimX.Duration = new Duration(TimeSpan.FromSeconds(0.15));
        DoubleAnimation dblAnimY = new DoubleAnimation();
        dblAnimY.From = scaleYFrom;
        dblAnimY.To = scaleYTo - 0.1;
        scaleYFrom = scaleYTo -0.1;
        scaleYTo -= 0.1;
        Duration = new Duration(TimeSpan.FromSeconds(0.15));
        scaleM.BeginAnimation(ScaleTransform.ScaleXProperty, dblAnimX);
        scaleM.BeginAnimation(ScaleTransform.ScaleYProperty, dblAnimY);
    }
}
private void rect_MouseMove_1(object sender, MouseEventArgs e)
{
    if (e.LeftButton == MouseButtonState.Pressed)
    {
        System.Windows.Point p = e.GetPosition(this);
        TranslateTransform tt = new TranslateTransform();
        tt.X = (p.X - mouseDownX);
        tt.Y = (p.Y - mouseDownY);
        rect.RenderTransform = tt;
    }
}

TranslateTransform cancels ScaleTransform

或者使用MatrixTransform:

var matrix = Matrix.Identity;
matrix.Scale(1.5, 2.5);
matrix.Translate(30, 60);
rect.RenderTransform = new MatrixTransform(matrix);

或者更短:

var matrix = new Matrix(1.5, 0, 0, 2.5, 30, 60);
rect.RenderTransform = new MatrixTransform(matrix);

或者更好的是，你避免每次都设置一个新的RenderTransform，只是更新变换矩阵:

// set RenderTransform once in constructor
rect.RenderTransform = new MatrixTransform()
...
// update matrix in event handler
((MatrixTransform)rect.RenderTransform).Matrix = new Matrix(...);

由于您提供的代码太长，我没有根据您的情况改编下面的示例。如果可以的话，请考虑只发布关键的部分。

要组合不同类型的Transform，可以使用TransformGroup，按此方式。

void Button_Click_1(object sender, RoutedEventArgs e)
{
    var button = sender as Button;
    var transformGroup = new TransformGroup();
    var scale = new ScaleTransform(1.5, 2.5);
    var translate = new TranslateTransform(30, 60);
    transformGroup.Children.Add(scale);
    transformGroup.Children.Add(translate);
    button.RenderTransform = transformGroup;
}

我也试图使用MatrixTransform与鼠标事件，并成功地使其工作如下:

public partial class MainWindow : Window
{
    ....
    // MyMatrixTransform could directly be defined in the xaml file        
    private MatrixTransform MyMatrixTransform = new MatrixTransform();
    public MainWindow()
    {
        InitializeComponent();
        MyMatrixTransform= new MatrixTransform();
        // MyCanvasArea is a canvas defined in the xaml file
        MyCanvasArea.RenderTransform = MyMatrixTransform;
        .....
    }
    // canvas_MouseWheel is attached to canvas in the xaml file as follow
    // <Canvas x:Name="MyCanvasArea" MouseWheel="canvas_MouseWheel" />
    void canvas_MouseWheel(object sender, MouseWheelEventArgs e)
    {
        if (e.Delta > 0)
        {
            Matrix matrix = MyMatrixTransform.Matrix;
            matrix.Scale(1.1, 1.1);
            MyMatrixTransform.Matrix = matrix;
        }
        else
        {
            Matrix matrix = MyMatrixTransform.Matrix;
            matrix.Scale(0.9, 0.9);
            MyMatrixTransform.Matrix = matrix;
        }
    }
    ....
}

可以在MatrixTransform中直接访问矩阵字段，但是我找不到方法。

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