InkOverlay.HitTestSelection Method

Article
10/19/2012

Returns a value that indicates which part of a selection, if any, was hit during a hit test.

Namespace: Microsoft.Ink
Assembly: Microsoft.Ink (in Microsoft.Ink.dll)

Syntax

'Declaration
Public Function HitTestSelection ( _
    X As Integer, _
    Y As Integer _
) As SelectionHitResult
'Usage
Dim instance As InkOverlay 
Dim X As Integer 
Dim Y As Integer 
Dim returnValue As SelectionHitResult 

returnValue = instance.HitTestSelection(X, _
    Y)

public SelectionHitResult HitTestSelection(
    int X,
    int Y
)

public:
SelectionHitResult HitTestSelection(
    int X, 
    int Y
)

public function HitTestSelection(
    X : int, 
    Y : int
) : SelectionHitResult

Parameters

X
Type: System.Int32

The x-position, in pixels, of the hit test.

Y
Type: System.Int32

The y-position, in pixels, of the hit test.

Return Value

Type: Microsoft.Ink.SelectionHitResult
A member of the SelectionHitResult enumeration, which specifies which part of a selection, if any, was hit during a hit test.

Remarks

This method is only useful if the InkOverlay.EditingMode property is set to Select.

Note

When running an ink app on a Windows XP desktop machine that is set to 120dpi, the HitTestSelection method is off by a scaling factor when the point supplied is converted from ink space to pixel space.

Examples

In this example, when the MouseDown event fires, a check is made to see if EditingMode is set to Select. If so, the HitTestSelection method is called to determine which part of the selection (if any) has been hit. If the hit occurs on any of the four main compass directions, as specified by the SelectionHitResult enumeration, the stroke objects that are selected are changed to a different color.

Private Sub mInkObject_MouseDown(ByVal sender As Object, ByVal e As CancelMouseEventArgs)

    If InkOverlayEditingMode.Select = mInkObject.EditingMode Then 
        Select Case mInkObject.HitTestSelection(e.X, e.Y)
            Case SelectionHitResult.North
                ChangeSelectionColor(Color.Green)
            Case SelectionHitResult.East
                ChangeSelectionColor(Color.Red)
            Case SelectionHitResult.South
                ChangeSelectionColor(Color.Purple)
            Case SelectionHitResult.West
                ChangeSelectionColor(Color.Blue)
        End Select 
    End If 
End Sub 

Private Sub ChangeSelectionColor(ByVal color As Color)
    Dim DA As DrawingAttributes = mInkObject.DefaultDrawingAttributes.Clone()
    DA.Color = color
    mInkObject.Selection.ModifyDrawingAttributes(DA)
    Using G As Graphics = CreateGraphics()
        ' Get the bounding box of the selection. The default is 
        ' to include the width of the strokes in the calculation. 
        ' The returned rectangle is measured in ink units. 
        Dim rInkUnits As Rectangle = mInkObject.Selection.GetBoundingBox()

        ' In selection mode, the selected strokes are drawn inflated 
        ' GetBoundingBox() does not take this into account 
        ' Rectangle rInkUnits is inflated to compensate
        rInkUnits.Inflate(53, 53)

        Dim topLeft As Point = rInkUnits.Location
        Dim bottomRight As Point = rInkUnits.Location + rInkUnits.Size

        ' get a Renderer object to make the conversion 
        Dim R As Renderer = New Renderer()

        ' convert the points to pixels
        R.InkSpaceToPixel(G, topLeft)
        R.InkSpaceToPixel(G, bottomRight)

        ' create a rectangle that is in pixels 
        Dim rPixelUnits As Rectangle = _
            New Rectangle(topLeft, New Size(bottomRight.X - topLeft.X, bottomRight.Y - topLeft.Y))

        ' Redraw the strokes
        mInkObject.Draw(rPixelUnits)

    End Using 
End Sub

private void mInkObject_MouseDown(object sender, CancelMouseEventArgs e)
{
    if (InkOverlayEditingMode.Select == mInkObject.EditingMode)
    {
        switch (mInkObject.HitTestSelection(e.X, e.Y))
        {
            case SelectionHitResult.North:
                ChangeSelectionColor(Color.Green);
                break;
            case SelectionHitResult.East:
                ChangeSelectionColor(Color.Red);
                break;
            case SelectionHitResult.South:
                ChangeSelectionColor(Color.Purple);
                break;
            case SelectionHitResult.West:
                ChangeSelectionColor(Color.Blue);
                break;
        }
    }
}

private void ChangeSelectionColor(Color color)
{
    DrawingAttributes DA = mInkObject.DefaultDrawingAttributes.Clone();
    DA.Color = color;
    mInkObject.Selection.ModifyDrawingAttributes(DA);
    using (Graphics G = CreateGraphics())
    {
        // Get the bounding box of the selection. The default is 
        // to include the width of the strokes in the calculation. 
        // The returned rectangle is measured in ink units.
        Rectangle rInkUnits = mInkObject.Selection.GetBoundingBox();

        // In selection mode, the selected strokes are drawn inflated 
        // GetBoundingBox() does not take this into account 
        // Rectangle rInkUnits is inflated to compensate
        rInkUnits.Inflate(53, 53);

        Point topLeft = rInkUnits.Location;
        Point bottomRight = rInkUnits.Location + rInkUnits.Size;

        // get a Renderer object to make the conversion
        Renderer R = new Renderer();

        // convert the points to pixels
        R.InkSpaceToPixel(G, ref topLeft);
        R.InkSpaceToPixel(G, ref bottomRight);

        // create a rectangle that is in pixels
        Rectangle rPixelUnits =
            new Rectangle(topLeft, new Size(bottomRight.X - topLeft.X, bottomRight.Y - topLeft.Y));

        // Redraw the strokes
        mInkObject.Draw(rPixelUnits);

    } 
}

Platforms

Windows 7, Windows Vista, Windows Server 2008 R2, Windows Server 2008

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Version Information

.NET Framework

Supported in: 3.0

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