StartTangent Property （ActiveX）

签名

工 务 局：

object.StartTangent

对象

类型：样条

此属性适用的对象。

属性值

只读：不

类型：变体（双精度的三元素数组）

表示样条的起始切线的方向矢量。

言论

当样条升高时，它将从插值（拟合）样条转换为控制点样条。这意味着在高程之后，样条不再具有拟合切线，并且样条的和属性不再可访问。编辑控制点样条的唯一方法是通过属性或理论方法。StartTangentEndTangentControlPointsSetControlPointGetControlPoint

例子

工 务 局：

Sub Example_StartTangent()
    ' This example creates a spline. It then queries the current setting for
    ' the StartTangent, and then changes the StartTangent to a new value.

    ' Create the spline
    Dim splineObj As AcadSpline
    Dim startTan(0 To 2) As Double
    Dim endTan(0 To 2) As Double
    Dim fitPoints(0 To 8) As Double
    Dim msg As String
    
    startTan(0) = 0.5: startTan(1) = 0.5: startTan(2) = 0
    endTan(0) = 0.5: endTan(1) = 0.5: endTan(2) = 0
    fitPoints(0) = 1: fitPoints(1) = 1: fitPoints(2) = 0
    fitPoints(3) = 5: fitPoints(4) = 5: fitPoints(5) = 0
    fitPoints(6) = 10: fitPoints(7) = 0: fitPoints(8) = 0
    Set splineObj = ThisDrawing.ModelSpace.AddSpline(fitPoints, startTan, endTan)
    
    ThisDrawing.Regen True
    GoSub GETPOINTS
    MsgBox "The StartTangent for the spline is  " & msg, vbInformation, "StartTangent Example"

    Dim newTan(0 To 2) As Double
    newTan(0) = 1.5: newTan(1) = 0.707: newTan(2) = 2
    
    ' Change the start tangent of Spline to (1.5, 0.707, 2)
    splineObj.EndTangent = newTan
    
    ThisDrawing.Regen True
    GoSub GETPOINTS
    MsgBox "The StartTangent has been changed to " & msg, vbInformation, "StartTangent Example"

    Exit Sub

GETPOINTS:
    Dim count As Integer
    msg = ""
    ' Get the coordinates from the start tangent
    For count = 0 To 2
        msg = msg & Format(splineObj.StartTangent(count), "0.###") & ", "
    Next
    msg = VBA.Left(msg, Len(msg) - 2)
    Return
End Sub

Visual LISP:

(vl-load-com)
(defun c:Example_StartTangent()
    ;; This example creates a spline. It then queries the current setting for
    ;; the StartTangent, and then changes the StartTangent to a new value.
    (setq acadObj (vlax-get-acad-object))
    (setq doc (vla-get-ActiveDocument acadObj))
  
    ;; Create the spline
    (setq startTan (vlax-3d-point 0.5 0.5 0)
          endTan (vlax-3d-point 0.5 0.5 0)
          fitPoints (vlax-make-safearray vlax-vbDouble '(0 . 8)))
    (vlax-safearray-fill fitPoints '(1 1 0
				                                 5 5 0
				                                 10 0 0
				                                )
    )
    
    ;; Create the spline
    (setq modelSpace (vla-get-ModelSpace doc))
    (setq splineObj (vla-AddSpline modelSpace fitPoints startTan endTan))

    (vla-ZoomAll acadObj)

    (setq msg "")

    ;; Get the coordinates from the start tangent
    (setq startTangent (vlax-safearray->list (vlax-variant-value (vla-get-StartTangent splineObj))))
    (setq msg (strcat msg (rtos (nth 0 startTangent) 2 3) ","
		                        (rtos (nth 1 startTangent) 2 3) ","
		                        (rtos (nth 2 startTangent) 2 3)))

    (alert (strcat "The StartTangent for the spline is " msg))

    ;; Change the start tangent of Spline to (1.5,0.707,2)
    (setq newTan (vlax-3d-point 1.5 0.707 2))
    (vla-put-StartTangent splineObj newTan)

    (vla-Regen doc :vlax-true)

    (setq msg "")
    (setq startTangent (vlax-safearray->list (vlax-variant-value (vla-get-StartTangent splineObj))))
    (setq msg (strcat msg (rtos (nth 0 startTangent) 2 3) ","
		                        (rtos (nth 1 startTangent) 2 3) ","
		                        (rtos (nth 2 startTangent) 2 3)))

    (alert (strcat "The StartTangent has been changed to " msg))
)