WPF自定义控件之ItemsControl鱼眼效果

WPF自定义控件之ItemsControl鱼眼效果已关闭评论
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所属分类：.NET技术

摘要

先获取鼠标在控件中的坐标，在获取其每一项相对于ItemsControl的坐标，然后计算每一项离当前鼠标的距离，在根据这个距离，对其每一项进行适当的缩放

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原理

实现

创建一个类，命名为FishEyeItemsControl

public class FishEyeItemsControl : ItemsControl

添加应用鱼眼效果方法（控制其控件的缩放）

private void ApplyFishEyeEffect(UIElement element, double strength, double additionalScale = 0.0) {     // 将鱼眼效果应用于控件的正中心位置      // 获取控件的宽度和高度     double width = element.RenderSize.Width;     double height = element.RenderSize.Height;      // 计算控件的正中心位置     double centerX = width / 2.0;     double centerY = height / 2.0;      // 创建 ScaleTransform 对象并设置缩放中心为控件的正中心     ScaleTransform scaleTransform = new ScaleTransform();     scaleTransform.CenterX = centerX;     scaleTransform.CenterY = centerY;      // 根据强度调整缩放比例     scaleTransform.ScaleX = strength + additionalScale;     scaleTransform.ScaleY = strength + additionalScale;      // 将 ScaleTransform 应用于控件的 RenderTransform     element.RenderTransform = scaleTransform; }

当鼠标移入到ItemsControl区域内时，计算其项距离鼠标距离，实现鱼眼效果

CalculateStrength方法可根据实际需求进行更改

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) {     // 根据距离计算变换的强度     var strength = 1.0;     strength = Math.Exp(-distance / 100);     return strength; }

当鼠标离开ItemsControl时，进行效果还原

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，如果未设置，当鼠标处于两个项之间的空间会触发OnMouseLeave

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

属性

依赖属性Scale是为了在Xaml中动态修改其效果

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>