DeleteStrokes Method
DeleteStrokes Method |
Deletes a InkStrokes collection from the Strokes collection of the InkDisp object.
Declaration
[C++]
HRESULT DeleteStrokes (
[in, optional, defaultvalue(0)] IInkStrokes* strokes
);
[Microsoft® Visual Basic® 6.0]
Public Sub DeleteStrokes([strokes As InkStrokes])
Parameters
strokes
[in] Specifies the collection of strokes to delete from the InkDisp object. The default value is NULL (Nothing in Visual Basic 6.0, which must be specified if using latebinding).
Return Value
| HRESULT value | Description |
|---|---|
| S_OK | Success. |
| E_POINTER | A parameter contained an invalid pointer. |
| E_OUTOFMEMORY | Cannot allocate memory that is used to perform the operation. |
| E_FAIL | An unspecified error occurred. |
| E_INK_MISMATCHED_INK_OBJECT | The InkDisp object of the strokes must match the known InkDisp object. |
| E_INK_EXCEPTION | An exception occurred inside the method. |
| E_UNEXPECTED | Unexpected parameter or property type. |
Remarks
This method deletes all of the strokes in the InkDisp object if no InkStrokes collection is passed in. To delete only one stroke at a time, call the DeleteStroke method.
The InkDisp object renumbers the indices of the remaining strokes in the InkDisp object if the strokes that were deleted do not fall at the end of the InkDisp object's collection of strokes.
Note: The contents of a InkStrokes collection become invalid when strokes that are contained in the collection are deleted from the InkDisp object.
DeleteStrokes can result in an error if called while the user is actively laying down ink.
Example
[Visual Basic 6.0]
This Visual Basic 6.0 example uses a command button Command1 to invoke a function, DeleteStrokesOnLeft, that deletes all of the strokes in the InkDisp object, theInkCollector.Ink, that are to the left of the ptLeft parameter in ink space, and returns a count of the deleted strokes.
Dim theInkCollector As InkCollector
Private Sub Command1_Click()
' On button press, delete all strokes with points
' to the left of a line at x=5000 in ink space
DeleteStrokesOnLeft 5000
Form1.Refresh
End Sub
Private Sub Form_Load()
Set theInkCollector = New InkCollector
theInkCollector.hWnd = Me.hWnd
theInkCollector.Enabled = True
End Sub
Public Function DeleteStrokesOnLeft( _
ByVal ptLeft As Long _
) As Long
Dim i As Integer
Dim ptTest As Long
Dim stroke As IInkStrokeDisp
Dim strokesToDelete As InkStrokes
Dim ptStrokePoints As Variant
' Create an object to hold strokes to be deleted
Set strokesToDelete = theInkCollector.Ink.CreateStrokes
For Each stroke In theInkCollector.Ink.Strokes
' The points are returned as an array of Long,
' in the form of x1, y1, x2, y2, ...
ptStrokePoints = stroke.GetPoints
' Determine the final x,y pair starting at 0
Dim pointUBound As Long
pointUBound = (UBound(ptStrokePoints) - 1) \ 2
For i = 0 To pointUBound
' Get the next point x value
ptTest = ptStrokePoints(i * 2)
' If there is a point in this stroke left of the parameter,
If ptTest < ptLeft Then
' add this stroke to the collection to delete
strokesToDelete.Add stroke
' then exit, because we don't need to test further.
Exit For
End If
Next
Next
If 0 < strokesToDelete.Count Then
' Delete the strokes we collected on the left
theInkCollector.Ink.DeleteStrokes strokesToDelete
End If
DeleteStrokesOnLeft = strokesToDelete.Count
End Function