Ink.NearestPoint 方法 (Point, Single%, Single%)

發行項
10/29/2008

傳回最接近指定點的 Stroke 物件，並傳回 Stroke 物件上最接近指定點的點，同時傳回指定點與 Ink 物件之 Stroke 物件上最接近點間的距離。

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

語法

'宣告
Public Function NearestPoint ( _
    point As Point, _
    <OutAttribute> ByRef pointOnStroke As Single, _
    <OutAttribute> ByRef distanceFromPacket As Single _
) As Stroke
'用途
Dim instance As Ink
Dim point As Point
Dim pointOnStroke As Single
Dim distanceFromPacket As Single
Dim returnValue As Stroke

returnValue = instance.NearestPoint(point, _
    pointOnStroke, distanceFromPacket)

public Stroke NearestPoint(
    Point point,
    out float pointOnStroke,
    out float distanceFromPacket
)

public:
Stroke^ NearestPoint(
    Point point, 
    [OutAttribute] float% pointOnStroke, 
    [OutAttribute] float% distanceFromPacket
)

public Stroke NearestPoint(
    Point point,
    /** @attribute OutAttribute */ /** @ref */float pointOnStroke,
    /** @attribute OutAttribute */ /** @ref */float distanceFromPacket
)

public function NearestPoint(
    point : Point, 
    pointOnStroke : float, 
    distanceFromPacket : float
) : Stroke

參數

point
型別：System.Drawing.Point
Ink 物件內指定的點，以筆墨空間座標表示。

pointOnStroke
型別：System.Single%
Stroke 物件上最接近 Ink 物件內指定點的點。

distanceFromPacket
型別：System.Single%
指定點與 Ink 物件中最接近之 Stroke 物件間的距離。

傳回值

型別：Microsoft.Ink.Stroke
包含 Point 的 Stroke，最接近 Ink 物件中的指定點。如果多個筆劃包含的 Point 與已知 Point (英文) 有相同的距離，這個結果的值就是任意值。

備註

distanceFromPacket 參數是描述指定點到 Stroke 物件的封套之間的距離。這是兩個點之間的距離，減去 Stroke 物件 DrawingAttributes 之 Width 屬性的一半。

範例

在這個範例中，如果 Stroke 物件包含的點位於筆墨控制項中心 500 HIMETRIC 單位內，則 Stroke 物件的色彩會變更為紅色。此外會建立新的 Stroke 物件，從所探索到最接近筆墨控制項中心的 Stroke 物件延伸到筆墨控制項中心。

Dim inkControl As Control = mInkOverlay.AttachedControl
' get the center of the ink control
Dim centerPt As Point = New Point(inkControl.Width / 2, inkControl.Height / 2)
Using g As Graphics = inkControl.CreateGraphics()
    ' convert center point to ink space coordinates
    mInkOverlay.Renderer.PixelToInkSpace(g, centerPt)
End Using
' get the nearest stroke
Dim pointOnStroke As Single
Dim distanceFromPacket As Single
Dim nStroke As Stroke = mInkOverlay.Ink.NearestPoint(centerPt, pointOnStroke, distanceFromPacket)
' nStroke will be null if there aren't any strokes
If Not IsNothing(nStroke) And distanceFromPacket <= 500.0 Then
    ' change the color of the nearest stroke to red
    nStroke.DrawingAttributes.Color = Color.Red
    'Dim ptIdx As Integer = DirectCast(Math.Round(pointOnStroke, MidpointRounding.ToEven), Integer)

    Dim ptIdx As Integer = CType(Math.Round(pointOnStroke, MidpointRounding.ToEven), Integer)

    ' create points from the center to the nearest point on the stroke
    Dim connectPts() As Point = _
            { _
                centerPt, _
                nStroke.GetPoint(ptIdx) _
            }
    ' create the stroke
    mInkOverlay.Ink.CreateStroke(connectPts)
    inkControl.Invalidate()
End If

Control inkControl = mInkOverlay.AttachedControl;
// get the center of the ink control
Point centerPt = new Point(inkControl.Width / 2, inkControl.Height / 2);
using (Graphics g = inkControl.CreateGraphics())
{
    // convert center point to ink space coordinates
    mInkOverlay.Renderer.PixelToInkSpace(g, ref centerPt);
}
// get the nearest stroke
float pointOnStroke;
float distanceFromPacket;
Stroke nStroke = mInkOverlay.Ink.NearestPoint(centerPt, out pointOnStroke, out distanceFromPacket);

// nStroke will be null if there aren't any strokes
if (nStroke != null && distanceFromPacket <= 500.0)
{
    // change the color of the nearest stroke to red
    nStroke.DrawingAttributes.Color = Color.Red;
    int ptIdx = (int)Math.Round(pointOnStroke, MidpointRounding.ToEven);
    // create points from the center to the nearest point on the stroke
    Point[] connectPts = new Point[2] 
    {
        centerPt, 
        nStroke.GetPoint(ptIdx)
    };
    // create the stroke
    mInkOverlay.Ink.CreateStroke(connectPts);
    inkControl.Invalidate();
}