缩放和平移问题翻译/ ScaleTransform WPF

1 回答

• 0

  以下简单派生的Canvas会将其子元素排列在由 Canvas.Left 和 Canvas.Top 属性值给出的变换位置 . 转换由 ChildPositionTransform 依赖项属性应用 .

  public class ZoomCanvas : Canvas
  {
      public static readonly DependencyProperty ChildPositionTransformProperty =
          DependencyProperty.Register(
              "ChildPositionTransform", typeof(Transform), typeof(ZoomCanvas),
              new FrameworkPropertyMetadata(
                  Transform.Identity, FrameworkPropertyMetadataOptions.AffectsArrange));
  
      public Transform ChildPositionTransform
      {
          get { return (Transform)GetValue(ChildPositionTransformProperty); }
          set { SetValue(ChildPositionTransformProperty, value); }
      }
  
      protected override Size ArrangeOverride(Size finalSize)
      {
          foreach (UIElement element in InternalChildren)
          {
              var x = GetLeft(element);
              var y = GetTop(element);
              var pos = new Point(double.IsNaN(x) ? 0d : x, double.IsNaN(y) ? 0d : y);
              ArrangeElement(element, ChildPositionTransform.Transform(pos));
          }
  
          return finalSize;
      }
  
      private void ArrangeElement(UIElement element, Point position)
      {
          element.Arrange(new Rect(position, element.DesiredSize));
      }
  }
  

  现在，您还可以通过优化ArrangeElement方法来考虑子元素的 HorizontalAlignment 和 VerticalAlignment 属性 .

  private void ArrangeElement(UIElement element, Point position)
  {
      if (element is FrameworkElement)
      {
          switch (((FrameworkElement)element).HorizontalAlignment)
          {
              case HorizontalAlignment.Center:
                  position.X -= element.DesiredSize.Width / 2;
                  break;
  
              case HorizontalAlignment.Right:
                  position.X -= element.DesiredSize.Width;
                  break;
  
              default:
                  break;
          }
  
          switch (((FrameworkElement)element).VerticalAlignment)
          {
              case VerticalAlignment.Center:
                  position.Y -= element.DesiredSize.Height / 2;
                  break;
  
              case VerticalAlignment.Bottom:
                  position.Y -= element.DesiredSize.Height;
                  break;
  
              default:
                  break;
          }
      }
  
      element.Arrange(new Rect(position, element.DesiredSize));
  }
  

  回复于 2024-04-29T14:22:08+08:00