InkOverlay.Draw Method

  • Article

InkOverlay.Draw Method

Sets a rectangle in which to redraw the ink within the InkOverlay object.

Definition

Visual Basic .NET Public Sub Draw( _
ByVal rDrawRect As Rectangle _
)
C# public void Draw(
Rectangle rDrawRect
);
Managed C++ public: void Draw(
Rectangle *rDrawRect
);

Parameters

rDrawRect System.Drawing.Rectangle. The rectangle in which to redraw the ink, in pixel coordinates.

Exceptions

ObjectDisposedException Leave Site: The InkOverlay object is disposed.

Remarks

When the rDrawRect parameter is null (Nothing in Microsoft® Visual Basic® .NET), the entire window is redrawn.

A good use of this method is to redraw strokes that have been programmically changed. You can also call the Control.Invalidate Leave Site method, but this causes a redrawing off all of the InkOverlay object's strokes. You can also call the Renderer.Draw method for this purpose, but the Renderer object is not able to draw any strokes as selected because it has no knowledge of which strokes are in the Selection collection.

Note: The AutoRedraw property must be set to true for the drawing to occur.

Examples

[C#]

This C# example is a method that changes the color of all the strokes in a Strokes collection that belong to the Ink object associated with an InkOverlay object, theInkOverlay. Changing the DrawingAttributes property of a Stroke object is not automatically and immediately visible. You can call the Invalidate Leave Site or Refresh Leave Site method on the control associated with theInkOverlay, but this causes a redrawing of all the Stroke objects in theInkOverlay. To achieve better performance, use the Draw method on the bounding box of the Strokes collection. Note that this means converting the bounding box from ink space coordinates to pixel coordinates.

private void ChangeColor(Strokes theStrokes, Color newColor)
{
    // Change the color of theStrokes
    foreach (Stroke stroke in theStrokes)
    {
        stroke.DrawingAttributes.Color = newColor;
    }

    // Convert bounding box to pixel coordinates
    Graphics g = CreateGraphics();
    Rectangle strokesBounds = theStrokes.GetBoundingBox();
    Point topLeft = strokesBounds.Location;
    Point bottomRight = strokesBounds.Location + strokesBounds.Size;
    theInkOverlay.Renderer.InkSpaceToPixel(g, ref topLeft);
    theInkOverlay.Renderer.InkSpaceToPixel(g, ref bottomRight);
    g.Dispose()
    strokesBounds = new Rectangle(topLeft,
        new Size(bottomRight.X - topLeft.X, bottomRight.Y - topLeft.Y));

    // Redraw the strokes
    theInkOverlay.Draw(strokesBounds);
}

[VB.NET]

This Visual Basic .NET example is a method that changes the color of all the strokes in a Strokes collection that belong to the Ink object associated with an InkOverlay object, theInkOverlay. Changing the DrawingAttributes property of a Stroke object is not automatically and immediately visible. You can call the Invalidate Leave Site or Refresh Leave Site method on the control associated with theInkOverlay, but this causes a redrawing of all the Stroke objects in theInkOverlay. To achieve better performance, use the Draw method on the bounding box of the Strokes collection. Note that this means converting the bounding box from ink space coordinates to pixel coordinates.

Private Sub ChangeColor(ByVal theStrokes As Strokes, ByVal newColor As Color)
    ' Change the color of theStrokes
    Dim theStroke As Stroke
    For Each theStroke In theStrokes
        theStroke.DrawingAttributes.Color = newColor
    Next

    'Convert bounding box to pixel coordinates
    Dim g As Graphics = CreateGraphics()
    Dim strokesBounds As Rectangle = theStrokes.GetBoundingBox()
    Dim topLeft As Point = strokesBounds.Location
    Dim bottomRight As Point = New Point(strokesBounds.Right, strokesBounds.Bottom)
    theInkOverlay.Renderer.InkSpaceToPixel(g, topLeft)
    theInkOverlay.Renderer.InkSpaceToPixel(g, bottomRight)
    g.Dispose()
    strokesBounds = New Rectangle(topLeft, _
        New Size(bottomRight.X - topLeft.X, bottomRight.Y - topLeft.Y))

    'Redraw the strokes
    theInkOverlay.Draw(strokesBounds)

    End Sub

See Also