StrokeIntersection.BeginIndex 属性

获取或设置 StrokeIntersection 结构的起点。

命名空间：  Microsoft.Ink
程序集：  Microsoft.Ink（在 Microsoft.Ink.dll 中）

语法

声明
Public Property BeginIndex As Single
用法
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)

属性值

类型：System.Single
相交段起点的浮点索引。

备注

如果笔画起始于相交区域内部，则此值为 –1。

浮点索引是一个浮点值，表示笔画中两点之间的某个位置。例如，如果 0.0 是笔画中的第一个点，而 1.0 是笔画中的第二个点，则 0.5 位于第一个点和第二个点的正中间。与之类似，浮点索引值 37.25 表示位于笔画点 37 和 38 之间连线的 25% 的位置。

示例

此示例将删除传入的 Stroke 对象在指定 Rectangle 结构内的所有线段。此示例通过检查 StrokeIntersection 结构来确定对传入的 Stroke 对象进行拆分的位置以及要删除的线段，从而实现此操作。

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);
        }
    }
}

平台

Windows Vista

.NET Framework 和 .NET Compact Framework 并不是对每个平台的所有版本都提供支持。有关支持的版本的列表，请参见.NET Framework 系统要求。

版本信息

.NET Framework

受以下版本支持：3.0

另请参见

参考

StrokeIntersection 结构

StrokeIntersection 成员

Microsoft.Ink 命名空间

StrokeIntersection.EndIndex