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WPF自定義控件實現(xiàn)ItemsControl魚眼效果

更新時間：2024年01月03日 09:37:55 作者：阿金啊

這篇文章主要為大家詳細(xì)介紹了WPF如何通過自定義控件實現(xiàn)ItemsControl魚眼效果,文中的示例代碼講解詳細(xì),需要的可以參考一下

原理

先獲取鼠標(biāo)在控件中的坐標(biāo)，在獲取其每一項相對于ItemsControl的坐標(biāo)，然后計算每一項離當(dāng)前鼠標(biāo)的距離，在根據(jù)這個距離，對其每一項進(jìn)行適當(dāng)?shù)目s放

實現(xiàn)

創(chuàng)建一個類，命名為FishEyeItemsControl

public class FishEyeItemsControl : ItemsControl

添加應(yīng)用魚眼效果方法（控制其控件的縮放）

private void ApplyFishEyeEffect(UIElement element, double strength, double additionalScale = 0.0)
{
    // 將魚眼效果應(yīng)用于控件的正中心位置

    // 獲取控件的寬度和高度
    double width = element.RenderSize.Width;
    double height = element.RenderSize.Height;

    // 計算控件的正中心位置
    double centerX = width / 2.0;
    double centerY = height / 2.0;

    // 創(chuàng)建 ScaleTransform 對象并設(shè)置縮放中心為控件的正中心
    ScaleTransform scaleTransform = new ScaleTransform();
    scaleTransform.CenterX = centerX;
    scaleTransform.CenterY = centerY;

    // 根據(jù)強(qiáng)度調(diào)整縮放比例
    scaleTransform.ScaleX = strength + additionalScale;
    scaleTransform.ScaleY = strength + additionalScale;

    // 將 ScaleTransform 應(yīng)用于控件的 RenderTransform
    element.RenderTransform = scaleTransform;
}

當(dāng)鼠標(biāo)移入到ItemsControl區(qū)域內(nèi)時，計算其項距離鼠標(biāo)距離，實現(xiàn)魚眼效果

CalculateStrength方法可根據(jù)實際需求進(jìn)行更改

protected override void OnMouseMove(MouseEventArgs e)
{
    base.OnMouseMove(e);
    Point mousePosition = e.GetPosition(this);
    hoveredIndex = -1;

    for (int i = 0; i < Items.Count; i++)
    {
        UIElement element = ItemContainerGenerator.ContainerFromIndex(i) as UIElement;

        if (element != null)
        {
            Point itemPosition = element.TranslatePoint(new Point(element.RenderSize.Width / 2, element.RenderSize.Height / 2), this);
            double distance = CalculateDistance(mousePosition, itemPosition);
            double strength = CalculateStrength(distance);

            ApplyFishEyeEffect(element, strength, Scale);

            if (distance < element.RenderSize.Width)
            {
                hoveredIndex = i;
            }
        }
    }
}

private double CalculateDistance(Point p1, Point p2)
{
    double dx = p1.X - p2.X;
    double dy = p1.Y - p2.Y;
    return Math.Sqrt(dx * dx + dy * dy);
}

private double CalculateStrength(double distance)
{
    // 根據(jù)距離計算變換的強(qiáng)度
    var strength = 1.0;
    strength = Math.Exp(-distance / 100);
    return strength;
}

當(dāng)鼠標(biāo)離開ItemsControl時，進(jìn)行效果還原

protected override void OnMouseLeave(MouseEventArgs e)
{
    base.OnMouseLeave(e);

    for (int i = 0; i < Items.Count; i++)
    {
        UIElement element = ItemContainerGenerator.ContainerFromIndex(i) as UIElement;

        if (element != null)
        {
            ApplyFishEyeEffect(element, 1.0);
        }
    }
    hoveredIndex = -1;
}

添加背景色，如果未設(shè)置，當(dāng)鼠標(biāo)處于兩個項之間的空間會觸發(fā)OnMouseLeave

public FishEyeItemsControl()
{
    this.Background = Brushes.Transparent;
}

屬性

依賴屬性Scale是為了在Xaml中動態(tài)修改其效果

private int hoveredIndex = -1;

#region DependencyProperty

public double Scale
{
    get { return (double)GetValue(ScaleProperty); }
    set { SetValue(ScaleProperty, value); }
}

// Using a DependencyProperty as the backing store for Scale.  This enables animation, styling, binding, etc...
public static readonly DependencyProperty ScaleProperty =
    DependencyProperty.Register("Scale", typeof(double), typeof(FishEyeItemsControl), new FrameworkPropertyMetadata(1.0, FrameworkPropertyMetadataOptions.BindsTwoWayByDefault));

#endregion

Xaml

<zWorkUi:FishEyeItemsControl
      Width="800"
      Height="600"
      ItemsSource="{Binding TestList}">
      <zWorkUi:FishEyeItemsControl.ItemsPanel>
          <ItemsPanelTemplate>
              <WrapPanel />
          </ItemsPanelTemplate>
      </zWorkUi:FishEyeItemsControl.ItemsPanel>
      <zWorkUi:FishEyeItemsControl.ItemTemplate>
          <DataTemplate>
              <Border
                  Width="50"
                  Height="50"
                  Margin="20,20"
                  Background="Red" />
          </DataTemplate>
      </zWorkUi:FishEyeItemsControl.ItemTemplate>
  </zWorkUi:FishEyeItemsControl>