Point geometry in WPF

February 27, 2023

I’m creating a geometry of lines and ellipses, now I want to add points to this geometry. I’m creating Ellipses with small radius to do this. But the problem is I’m applying transforms to this geometry. So when I translate and scale, the points get a lot bigger. How do I add points to this geometry such that it doesn’t gets bigger while scaling.

This is how I’m creating the point geometry:

public static Path PointsGeometry(List<Point> Locations, Transform transform)
    {
        GeometryGroup geometries = new GeometryGroup();
        foreach (Point Location in Locations)
        {
            geometries.Children.Add(new EllipseGeometry
                {
                    Center = Location,
                    RadiusX = .5,
                    RadiusY = .5,
                }
            );
        }

        geometries.Transform = transform;

        Path path = new Path
        {
            Fill = Brushes.WhiteSmoke,
            Data = geometries,
        };

        return path;
    }

>Solution :

In order to draw "dots", you may draw lines with zero length and round stroke caps:

public static Path PointsGeometry(
    IEnumerable<Point> locations, Transform transform)
{
    var geometries = new GeometryGroup { Transform = transform };

    foreach (Point location in locations)
    {
        geometries.Children.Add(new LineGeometry
        {
            StartPoint = location,
            EndPoint = location
        });
    }

    var path = new Path
    {
        Stroke = Brushes.WhiteSmoke,
        StrokeThickness = 2,
        StrokeStartLineCap = PenLineCap.Round,
        StrokeEndLineCap = PenLineCap.Round,
        Data = geometries,
    };

    return path;
}

Or with a PathGeometry instead of a GeometryGroup:

public static Path PointsGeometry(
    IEnumerable<Point> locations, Transform transform)
{
    var geometry = new PathGeometry { Transform = transform };

    foreach (Point location in locations)
    {
        var figure = new PathFigure { StartPoint = location };
        figure.Segments.Add(new LineSegment(location, true));
        geometry.Figures.Add(figure);
    }

    var path = new Path
    {
        Stroke = Brushes.WhiteSmoke,
        StrokeThickness = 2,
        StrokeStartLineCap = PenLineCap.Round,
        StrokeEndLineCap = PenLineCap.Round,
        Data = geometry,
    };

    return path;
}