关于计算定义的面积 （VBA/ActiveX）

从用户处获取点指定的区域

• 在循环中使用该方法从用户那里获取点。GetPoint
• 根据用户提供的点创建轻量级折线。使用该方法创建折线。AddLightweightPolyline
• 使用该属性获取新创建的折线的面积。Area
• 使用该方法擦除折线。Erase

计算由用户输入的点定义的区域

本示例提示用户输入 5 个点。然后，从输入的点中创建折线。折线是闭合的，折线的面积显示在消息框中。

Sub Ch3_CalculateDefinedArea()
  Dim p1 As Variant
  Dim p2 As Variant
  Dim p3 As Variant
  Dim p4 As Variant
  Dim p5 As Variant

  ' Get the points from the user
  p1 = ThisDrawing.Utility.GetPoint(, vbCrLf & "First point: ")
  p2 = ThisDrawing.Utility.GetPoint(p1, vbCrLf & "Second point: ")
  p3 = ThisDrawing.Utility.GetPoint(p2, vbCrLf & "Third point: ")
  p4 = ThisDrawing.Utility.GetPoint(p3, vbCrLf & "Fourth point: ")
  p5 = ThisDrawing.Utility.GetPoint(p4, vbCrLf & "Fifth point: ")

  ' Create the 2D polyline from the points
  Dim polyObj As AcadLWPolyline
  Dim vertices(0 To 9) As Double
  vertices(0) = p1(0): vertices(1) = p1(1)
  vertices(2) = p2(0): vertices(3) = p2(1)
  vertices(4) = p3(0): vertices(5) = p3(1)
  vertices(6) = p4(0): vertices(7) = p4(1)
  vertices(8) = p5(0): vertices(9) = p5(1)
  Set polyObj = ThisDrawing.ModelSpace.AddLightWeightPolyline(vertices)
  polyObj.Closed = True
  ThisDrawing.Application.ZoomAll

  ' Display the area for the polyline
  MsgBox "The area defined by the points is " & _
  polyObj.Area, , "Calculate Defined Area"
End Sub