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计算定义区域（.NET）

2024-5-18 18:48| 发布者: admin| 查看: 191| 评论: 0|原作者: admin|来自: AutoCAD

计算定义区域（.NET）

如果要计算的面积基于用户指定的点，则可以考虑在内存中创建一个对象，例如轻量级折线，然后在丢弃对象之前查询该对象的面积。以下步骤说明如何实现此目的：

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。创建新的折线对象。指定顶点的数量和它们应位于的点。
使用该属性获取新创建的折线的面积。Area
使用其方法处理折线。Dispose

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。由于折线未添加到块中，因此需要在命令结束之前对其进行处置。

VB.NET

Imports Autodesk.AutoCAD.ApplicationServices
Imports Autodesk.AutoCAD.DatabaseServices
Imports Autodesk.AutoCAD.Geometry
Imports Autodesk.AutoCAD.EditorInput
Imports Autodesk.AutoCAD.Runtime
 
<CommandMethod("CalculateDefinedArea")> _
Public Sub CalculateDefinedArea()
    '' Prompt the user for 5 points
    Dim acDoc As Document = Application.DocumentManager.MdiActiveDocument
 
    Dim pPtRes As PromptPointResult
    Dim colPt As Point2dCollection = New Point2dCollection
    Dim pPtOpts As PromptPointOptions = New PromptPointOptions("")
 
    '' Prompt for the first point
    pPtOpts.Message = vbLf & "Specify first point: "
    pPtRes = acDoc.Editor.GetPoint(pPtOpts)
    colPt.Add(New Point2d(pPtRes.Value.X, pPtRes.Value.Y))
 
    '' Exit if the user presses ESC or cancels the command
    If pPtRes.Status = PromptStatus.Cancel Then Exit Sub
 
    Dim nCounter As Integer = 1
 
    While (nCounter <= 4)
        '' Prompt for the next points
        Select Case nCounter
            Case 1
                pPtOpts.Message = vbLf & "Specify second point: "
            Case 2
                pPtOpts.Message = vbLf & "Specify third point: "
            Case 3
                pPtOpts.Message = vbLf & "Specify fourth point: "
            Case 4
                pPtOpts.Message = vbLf & "Specify fifth point: "
        End Select
 
        '' Use the previous point as the base point
        pPtOpts.UseBasePoint = True
        pPtOpts.BasePoint = pPtRes.Value
 
        pPtRes = acDoc.Editor.GetPoint(pPtOpts)
        colPt.Add(New Point2d(pPtRes.Value.X, pPtRes.Value.Y))
 
        If pPtRes.Status = PromptStatus.Cancel Then Exit Sub
 
        '' Increment the counter
        nCounter = nCounter + 1
   End While
 
    '' Create a polyline with 5 points
    Using acPoly As Polyline = New Polyline()
        acPoly.AddVertexAt(0, colPt(0), 0, 0, 0)
        acPoly.AddVertexAt(1, colPt(1), 0, 0, 0)
        acPoly.AddVertexAt(2, colPt(2), 0, 0, 0)
        acPoly.AddVertexAt(3, colPt(3), 0, 0, 0)
        acPoly.AddVertexAt(4, colPt(4), 0, 0, 0)
 
        '' Close the polyline
        acPoly.Closed = True
 
        '' Query the area of the polyline
        Application.ShowAlertDialog("Area of polyline: " & _
                                    acPoly.Area.ToString())
 
        '' Dispose of the polyline
    End Using
End Sub

C#

using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.Geometry;
using Autodesk.AutoCAD.EditorInput;
using Autodesk.AutoCAD.Runtime;
 
[CommandMethod("CalculateDefinedArea")]
public static void CalculateDefinedArea()
{
    // Prompt the user for 5 points
    Document acDoc = Application.DocumentManager.MdiActiveDocument;
 
    PromptPointResult pPtRes;
    Point2dCollection colPt = new Point2dCollection();
    PromptPointOptions pPtOpts = new PromptPointOptions("");
 
    // Prompt for the first point
    pPtOpts.Message = "\nSpecify first point: ";
    pPtRes = acDoc.Editor.GetPoint(pPtOpts);
    colPt.Add(new Point2d(pPtRes.Value.X, pPtRes.Value.Y));
 
    // Exit if the user presses ESC or cancels the command
    if (pPtRes.Status == PromptStatus.Cancel) return;
 
    int nCounter = 1;
 
    while (nCounter <= 4)
    {
        // Prompt for the next points
        switch(nCounter)
        {
            case 1:
                pPtOpts.Message = "\nSpecify second point: ";
                break;
            case 2:
                pPtOpts.Message = "\nSpecify third point: ";
                break;
            case 3:
                pPtOpts.Message = "\nSpecify fourth point: ";
                break;
            case 4:
                pPtOpts.Message = "\nSpecify fifth point: ";
                break;
        }
 
        // Use the previous point as the base point
        pPtOpts.UseBasePoint = true;
        pPtOpts.BasePoint = pPtRes.Value;
 
        pPtRes = acDoc.Editor.GetPoint(pPtOpts);
        colPt.Add(new Point2d(pPtRes.Value.X, pPtRes.Value.Y));
 
        if (pPtRes.Status == PromptStatus.Cancel) return;
 
        // Increment the counter
        nCounter = nCounter + 1;
    }
 
    // Create a polyline with 5 points
    using (Polyline acPoly = new Polyline())
    {
        acPoly.AddVertexAt(0, colPt[0], 0, 0, 0);
        acPoly.AddVertexAt(1, colPt[1], 0, 0, 0);
        acPoly.AddVertexAt(2, colPt[2], 0, 0, 0);
        acPoly.AddVertexAt(3, colPt[3], 0, 0, 0);
        acPoly.AddVertexAt(4, colPt[4], 0, 0, 0);
 
        // Close the polyline
        acPoly.Closed = true;
 
        // Query the area of the polyline
        Application.ShowAlertDialog("Area of polyline: " +
                                    acPoly.Area.ToString());
 
        // Dispose of the polyline
    }
}

VBA/ActiveX 代码参考

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。与 AutoCAD .NET API 示例不同，折线不是在内存中创建的，而是作为数据库驻留对象创建并添加到模型空间中。因此，在获得折线的面积后，将其删除。

Sub 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 & "Specify first point: ")
    p2 = ThisDrawing.Utility.GetPoint(p1, vbCrLf & "Specify second point: ")
    p3 = ThisDrawing.Utility.GetPoint(p2, vbCrLf & "Specify third point: ")
    p4 = ThisDrawing.Utility.GetPoint(p3, vbCrLf & "Specify fourth point: ")
    p5 = ThisDrawing.Utility.GetPoint(p4, vbCrLf & "Specify 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
 
    ' Display the area for the polyline
    MsgBox "The area defined by the points is " & _
           polyObj.Area, , "Calculate Defined Area"
 
    ' Remove the polyline
    polyObj.Delete
End Sub