StrokeIntersection.BeginIndex 屬性

取得或設定 StrokeIntersection 結構的開始點。

命名空間： Microsoft.Ink
組件： Microsoft.Ink (在 Microsoft.Ink.dll 中)

語法

'宣告
Public Property BeginIndex As Single
'用途
Dim instance As StrokeIntersection
Dim value As Single

value = instance.BeginIndex

instance.BeginIndex = value

public float BeginIndex { get; set; }

public:
property float BeginIndex {
    float get ();
    void set (float value);
}

/** @property */
public float get_BeginIndex()
/** @property */
public  void set_BeginIndex(float value)

public function get BeginIndex () : float
public function set BeginIndex (value : float)

屬性值

型別：System.Single
交集起點的浮點索引。

備註

如果筆劃的起點是在交集區內，這個值就是 -1。

浮點索引是表示筆劃中兩點之間某個位置的浮點值。舉例來說，如果 0.0 是筆劃的第一點，而 1.0 是筆劃的第二點，0.5 即為第一點和第二點之間的中間處。同樣地，浮點索引值 37.25 則表示筆劃中沿著 37 和 38 兩點間線條上百分之 25 的位置。

範例

這個範例會刪除傳遞的 Stroke 物件中位於指定之矩形 (英文) 結構內的所有區段。這是透過檢查 StrokeIntersection 結構，找出傳遞之 Stroke 物件的分割位置以及要刪除的區段來完成的。

Private Sub DeleteInsideRectangle(ByVal S As Stroke, ByVal R As Rectangle)
    ' get the StrokeIntersection array
    Dim SI() As StrokeIntersection = S.GetRectangleIntersections(R)
    ' examine each StrokeIntersection
    ' must work backwards through the array so that when splitting, 
    ' the remaining intersections are still valid for S
    For k As Integer = SI.Length - 1 To 0 Step -1

        Dim enterRect As Single = SI(k).BeginIndex
        Dim exitRect As Single = SI(k).EndIndex

        ' check if the whole stroke is inside the rectangle
        ' if so, delete the stroke
        If enterRect = -1 And exitRect = -1 Then
            S.Ink.DeleteStroke(S)
            Continue For
        End If

        ' check if a segment enters and exits the rectangle
        ' if so, split and delete the segment inside the rectangle
        If enterRect > 0 And exitRect > 0 Then
            ' the stroke resulting from split() is outside, keep it
            S.Split(exitRect)
            ' the stroke from this split() is inside, delete it
            Dim temp As Stroke = S.Split(enterRect)
            temp.Ink.DeleteStroke(temp)
            Continue For
        End If

        ' check if stroke starts inside the rectangle and goes outside
        ' if so, split and delete the segment inside the rectangle
        If enterRect = -1 And exitRect > 0 Then
            ' the stroke resulting from split() is outside, keep it
            S.Split(exitRect)
            ' delete the remaining segment of the stroke
            S.Ink.DeleteStroke(S)
            Continue For
        End If

        ' check if stroke starts outside the rectangle and ends inside
        ' if so, split and delete the segment inside the rectangle
        If enterRect > 0 And exitRect = -1 Then
            Dim temp2 As Stroke = S.Split(enterRect)
            temp2.Ink.DeleteStroke(temp2)
        End If
    Next
End Sub

private void DeleteInsideRectangle(Stroke S, Rectangle R)
{
    // get the StrokeIntersection array
    StrokeIntersection[] SI = S.GetRectangleIntersections(R);

    // examine each StrokeIntersection
    // must work backwards through the array so that when splitting, 
    // the remaining intersections are still valid for S
    for (int k = SI.Length - 1; k >= 0; k--)
    {
        float enterRect = SI[k].BeginIndex;
        float exitRect = SI[k].EndIndex;

        // check if the whole stroke is inside the rectangle
        // if so, delete the stroke
        if (enterRect == -1 && exitRect == -1)
        {
            S.Ink.DeleteStroke(S);
            continue;
        }

        // check if a segment enters and exits the rectangle
        // if so, split and delete the segment inside the rectangle
        if (enterRect > 0 && exitRect > 0)
        {
            // the stroke resulting from split() is outside, keep it
            S.Split(exitRect);
            // the stroke from this split() is inside, delete it
            Stroke temp = S.Split(enterRect);
            temp.Ink.DeleteStroke(temp);
            continue;
        }

        // check if stroke starts inside the rectangle and goes outside
        // if so, split and delete the segment inside the rectangle
        if (enterRect == -1 && exitRect > 0)
        {
            // the stroke resulting from split() is outside, keep it
            S.Split(exitRect);
            // delete the remaining segment of the stroke
            S.Ink.DeleteStroke(S);
            continue;
        }

        // check if stroke starts outside the rectangle and ends inside
        // if so, split and delete the segment inside the rectangle
        if (enterRect > 0 && exitRect == -1)
        {
            Stroke temp2 = S.Split(enterRect);
            temp2.Ink.DeleteStroke(temp2);
        }
    }
}