在Adorner上绘图

2023-11-20 07:26 26阅读 0赞

第一种，我们可以使用VisualCollection，它是一种轻量级的绘图方式。那么如何在adorner上使用VisualCollection呢？

首先要重写属性与方法：

private VisualCollection visualChildren;
            protected override int VisualChildrenCount
            {
                get
                {
                    return this.visualChildren.Count;
                }
            }
    
            protected override Visual GetVisualChild(int index)
            {
                return this.visualChildren[index];
            }

添加一个子元素Canvas,然后在Canvs上面绘图

private Pen drawingPen;  
     private Canvas adornerCanvas;
    
      public ConnectionAdorner(DesignerCanvas designer, Connection connection)
                : base(designer)
            {
                
                adornerCanvas = new Canvas();
                this.visualChildren = new VisualCollection(this);
                this.visualChildren.Add(adornerCanvas);
    
                drawingPen = new Pen(Brushes.LightSlateGray, 1);
                drawingPen.LineJoin = PenLineJoin.Round;
            }

第二种就是直接重写OnRender方法，使用DrawingContext绘图

protected override void OnRender(DrawingContext dc)
            {
                base.OnRender(dc);
                dc.DrawGeometry(null, drawingPen, this.pathGeometry);
    
                // without a background the OnMouseMove event would not be fired
                // Alternative: implement a Canvas as a child of this adorner, like
                // the ConnectionAdorner does.
                dc.DrawRectangle(Brushes.Transparent, null, new Rect(RenderSize));
            }

在Adorner上绘图

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