HitTest(Point, Single) Method [InkDisp Class]
HitTest(Point, Single) Method [InkDisp Class] |
Retrieves the InkStrokes collection that are either completely inside or intersected by a known circle.
Declaration
[C++]
HRESULT HitTestCircle (
[in] long x,
[in] long y,
[in] float radius,
[out, retval] IInkStrokes **Strokes
);
[Microsoft® Visual Basic® 6.0]
Public Function HitTestCircle( _
x As Long, _
y As Long, _
radius As Single _
) As InkStrokes;
Parameters
radius
[in] The radius of the circle to use in the hit test, in ink space units.
x
[in] The x-position of the center of the hit test circle in ink space units.
y
[in] The y-position of the center of the hit test circle in ink space units.
Strokes
[out] Returns the collection of strokes that are either completely inside or intersected by the specified circle.
Return Value
| HRESULT value | Description |
|---|---|
| S_OK | Success. |
| E_POINTER | A parameter contained an invalid pointer. |
| E_INK_EXCEPTION | An exception occurred inside the method. |
| E_INVALIDARG | Invalid display handle. |
| E_UNEXPECTED | Unexpected parameter or property type. |
Remarks
If a stroke intersects the circle, the complete stroke is returned.
The method computes the intersection, considering the full set of drawing attributes that apply to the stroke, including the full pen width, Bezier smoothing (if present), and shape of the pen tip.
After a rotation or shear transform has been performed on a stroke or a collection of strokes, the transformed x- and y-coordinates are no longer concentric with the original coordinates. Because of this, the radius argument should not be calculated from the x- or y-coordinates.
To determine which points of a known stroke intersect the test area, call the HitTest method of the IInkStrokeDisp object.
The application must always pass in a destination pointer for the resulting collection of strokes. If there are no intersections, the collection has a count of zero.
Example
[Visual Basic 6.0]
This Visual Basic 6.0 example shows how to find the InkStrokes collection that is associated with the smallest set of IInkRecognitionAlternate objects that include the strokes selected by clicking the mouse in the drawing space of Form1, where the ink strokes have been recognized and the result is in an IInkRecognitionResult object, theRecognitionResult. This example starts with a standard exe application, adds a reference to the Microsoft Tablet PC Type Library, and has a text box Text1 and a check box HitTestMode added to the form. When the check box is unchecked, ink is collected and recognized, with the top alternate placed in the text box. When the check box is checked, a click with the mouse or a tap with the pen will use HitTest(Point, Single) to find the collection of strokes within a hit test radius of 200 ink space units and color it red.
Option Explicit
Dim WithEvents theInkCollector As InkCollector
Dim WithEvents theRecognizerContext As InkRecognizerContext
Dim theRecognitionResult As IInkRecognitionResult
Dim hasRecoResult As Boolean
Dim theStrokes As InkStrokes
Private Sub HitTestMode_Click()
theInkCollector.Enabled = Not theInkCollector.Enabled
End Sub
Private Sub Form_Load()
ScaleMode = vbPixels
'Initialize the InkCollector
Set theInkCollector = New InkCollector
theInkCollector.hWnd = Me.hWnd
theInkCollector.Enabled = True
'Create new RecognizerContext
Dim theRecognizers As New InkRecognizers
Dim theRecognizer As IInkRecognizer
Set theRecognizer = theRecognizers.GetDefaultRecognizer
Set theRecognizerContext = theRecognizer.CreateRecognizerContext
'Initialize the recognizer's strokes
'and assign them to the RecognizerContext
Set theStrokes = theInkCollector.ink.Strokes
Set theRecognizerContext.Strokes = theStrokes
'Clear the hit test check box
HitTestMode.Value = 0
hasRecoResult = False
End Sub
Private Sub Form_MouseDown( _
Button As Integer, Shift As Integer, X As Single, Y As Single)
Dim inkX As Long
Dim inkY As Long
Dim hitStrokes As InkStrokes
Dim AltStrokes As InkStrokes
' Convert the mouse down to ink space coordinates
If hasRecoResult And HitTestMode.Value = 1 Then
inkX = CLng(X)
inkY = CLng(Y)
theInkCollector.Renderer.PixelToInkSpace Form1.hDC, inkX, inkY
'Get the stroke set hit by the mouse (within a radius
'of 200 HIMETRIC) and color it red.
Set hitStrokes = theInkCollector.ink.HitTestCircle(inkX, inkY, 200)
If hitStrokes.Count > 0 Then
Set AltStrokes = _
theRecognitionResult.TopAlternate.GetStrokesFromStrokeRanges(hitStrokes)
Dim theStroke As IInkStrokeDisp
For Each theStroke In theInkCollector.ink.Strokes
theStroke.DrawingAttributes.Color = RGB(0, 0, 0)
Next
For Each theStroke In AltStrokes
theStroke.DrawingAttributes.Color = RGB(255, 0, 0)
Next
Form1.Refresh
End If
End If
End Sub
Private Sub theRecognizerContext_RecognitionWithAlternates( _
ByVal RecognitionResult As IInkRecognitionResult, _
ByVal CustomData As Variant, _
ByVal RecognitionStatus As MSINKAUTLib.InkRecognitionStatus)
Set theRecognitionResult = RecognitionResult
'Update the text box with the top result
Text1.Text = theRecognitionResult.TopString
hasRecoResult = True
End Sub
Private Sub theInkCollector_Stroke( _
ByVal Cursor As MSINKAUTLib.IInkCursor, _
ByVal Stroke As MSINKAUTLib.IInkStrokeDisp, _
Cancel As Boolean)
'When a new stroke is collected, add it to
'the RecognizerContext's strokes collection
theStrokes.Add Stroke
'Tell the RecognizerContext to recognize
theRecognizerContext.BackgroundRecognizeWithAlternates
End Sub