WPF DrawGeometry does not draw stroke

Question

I hope this question was not asked before, I searched everywhere.

My problem is that I'm drawing a set of coordinates on my wpf usercontrol with points, I managed to fill my polygon with background color but not with a stroke. Stoke for some reason is not drawing?

Here is my code on the OnRender event using the DrawingContext

System.Windows.Media.Pen penDrawing = new System.Windows.Media.Pen(System.Windows.Media.Brushes.OrangeRed, 2);

                            drawingContext.DrawGeometry(System.Windows.Media.Brushes.LightSeaGreen, penDrawing, streamGeometry);

Code in detail

StreamGeometry streamGeometry = new StreamGeometry();

System.Windows.Point firstCoordinate = new System.Windows.Point();

System.Windows.Point lastCoordinateAdded = new System.Windows.Point();

bool isMainPolygon = true;

using (StreamGeometryContext geometryContext = streamGeometry.Open())
{
    PointCollection points = new PointCollection();

    firstCoordinate = new System.Windows.Point(coordinatePoints.ProjectedCoordinates[0].X, coordinatePoints.ProjectedCoordinates[0].Y);

    geometryContext.BeginFigure(firstCoordinate, true, true);

    System.Windows.Media.Pen penDrawing = new System.Windows.Media.Pen(System.Windows.Media.Brushes.OrangeRed, 5);

    penDrawing.EndLineCap = PenLineCap.Round;

    penDrawing.DashCap = PenLineCap.Round;

    penDrawing.LineJoin = PenLineJoin.Round;

    penDrawing.StartLineCap = PenLineCap.Round;

    penDrawing.MiterLimit = 10.0;

    for (int i = 1; i < coordinatePoints.ProjectedCoordinates.Count; i++)
    {
        lastCoordinateAdded = new System.Windows.Point() { X = coordinatePoints.ProjectedCoordinates[i].X, Y = coordinatePoints.ProjectedCoordinates[i].Y };

        points.Add(lastCoordinateAdded);

        //////Check to see if Polygon is done drawing
        if (firstCoordinate == lastCoordinateAdded)
        {
            geometryContext.PolyLineTo(points, true, true);

            //drawingContext.DrawGeometry(isMainPolygon ? System.Windows.Media.Brushes.Green : System.Windows.Media.Brushes.White, pen, streamGeometry);

            streamGeometry.Freeze();

            drawingContext.DrawGeometry(null, penDrawing, streamGeometry);

            points = new PointCollection();

            streamGeometry = new StreamGeometry();

            if (i + 1 < coordinatePoints.ProjectedCoordinates.Count)
            {
                i++;

                isMainPolygon = false;

                firstCoordinate = new System.Windows.Point(coordinatePoints.ProjectedCoordinates[i].X, coordinatePoints.ProjectedCoordinates[i].Y);

                geometryContext.BeginFigure(firstCoordinate, true, true);
            }
        }
    }

    geometryContext.PolyLineTo(points, true, true);
}

coordinatePoints.State = Enums.CoordinateEnum.None;

}

I will glad to provide more details.

Thanks a million.

It's the OrangeRed that you are not seeing? Why not make its size more than 2? — Rui, Feb 13 '14 at 14:04
@Rui i would like to see the code that generates the geometry. are the figure segments set to stroked? — Gusdor, Feb 13 '14 at 14:09
What is the extent of the geometry? I believe the stroke width might be scaled down so much to fit the extent that it becomes invisible. — 500 - Internal Server Error, Feb 13 '14 at 14:41
It might be possible I am doing a scale transformation, but i did set the stroke size to something like 100. I did remove the fill just to null to see if I can see the stroke no luck though. Thanks for the help guys — Ockert, Feb 14 '14 at 06:21
@500 - Internal Server Error Thanks a million i increased the stoke size to 200 and when zooming in i could see the line. If you post as answer i will mark as correct one :) — Ockert, Feb 14 '14 at 06:33

score 1 · Answer 1 · answered Feb 13 '14 at 14:13

1

When you create you geometry, make sure you set the stroked parameter on the StreamGeometryContext.LineTo method.

// Draw a line to the next specified point.
ctx.LineTo(new Point(100, 100), true /* is stroked */, false /* is smooth join */);
//                              ↑
//                              This parameter needs to be true.

answered Feb 13 '14 at 14:13

Gusdor

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I added the full length of code in the method, I did set the PolyLineTo property IsStroked to true. – Ockert Feb 14 '14 at 06:24

score 0 · Accepted Answer · answered Feb 14 '14 at 20:46

0

As with everything, WPF scales the width of lines, so if the stroke width is too narrow relative to the extent of the geometry, the stroke can become invisible.

answered Feb 14 '14 at 20:46

500 - Internal Server Error

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WPF DrawGeometry does not draw stroke

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