/// <summary>
        /// Translates a way.
        /// </summary>
        /// <param name="scene">The scene to add primitives to.</param>
        /// <param name="projection">The projection used to convert the objects.</param>
        /// <param name="way"></param>
        private void TranslateWay(Scene2D scene, IProjection projection, CompleteWay way)
        {
            // build the rules.
            List<MapCSSRuleProperties> rules =
                this.BuildRules(new MapCSSObject(way));

            // validate what's there.
            if (rules.Count == 0)
            {
                return;
            }

            // get x/y.
            double[] x = null, y = null;
            if (x == null)
            { // pre-calculate x/y.
                x = new double[way.Nodes.Count];
                y = new double[way.Nodes.Count];
                for (int idx = 0; idx < way.Nodes.Count; idx++)
                {
                    x[idx] = projection.LongitudeToX(
                        way.Nodes[idx].Coordinate.Longitude);
                    y[idx] = projection.LatitudeToY(
                        way.Nodes[idx].Coordinate.Latitude);
                }

                // simplify.
                if (x.Length > 2)
                {
                    double[][] simplified = SimplifyCurve.Simplify(new double[][] {x, y}, 0.0001);
                    x = simplified[0];
                    y = simplified[1];
                }
            }

            // add the z-index.
            foreach (var rule in rules)
            {
                float minZoom = (float)projection.ToZoomFactor(rule.MinZoom);
                float maxZoom = (float)projection.ToZoomFactor(rule.MaxZoom);

                int zIndex ;
                if (!rule.TryGetProperty<int>("zIndex", out zIndex))
                {
                    zIndex = 0;
                }

                // interpret the results.
                if (x != null)
                { // there is a valid interpretation of this way.
                    int color;
                    if (way.IsOfType(MapCSSTypes.Area))
                    { // the way is an area. check if it can be rendered as an area.
                        int fillColor;
                        if (rule.TryGetProperty("fillColor", out fillColor))
                        { // render as an area.
                            scene.AddPolygon(this.CalculateSceneLayer(OffsetArea, zIndex), minZoom, maxZoom, x, y, fillColor, 1, true);
                            if (rule.TryGetProperty("color", out color))
                            {
                                scene.AddPolygon(this.CalculateSceneLayer(OffsetCasing, zIndex), minZoom, maxZoom, x, y, color, 1, false);
                            }
                        }
                    }

                    // the way has to rendered as a line.
                    LineJoin lineJoin;
                    if (!rule.TryGetProperty("lineJoin", out lineJoin))
                    {
                        lineJoin = LineJoin.Miter;
                    }
                    int[] dashes;
                    if (!rule.TryGetProperty("dashes", out dashes))
                    {
                        dashes = null;
                    }
                    if (rule.TryGetProperty("color", out color))
                    {
                        float casingWidth;
                        int casingColor;
                        if (!rule.TryGetProperty("casingWidth", out casingWidth))
                        {
                            casingWidth = 0;
                        }
                        if(!rule.TryGetProperty("casingColor", out casingColor))
                        { // casing: use the casing layer.
                            casingColor = -1;
                        }
                        float width;
                        if (!rule.TryGetProperty("width", out width))
                        {
                            width = 1;
                        }
                        if (casingWidth > 0)
                        { // adds the casing
                            scene.AddLine(this.CalculateSceneLayer(OffsetCasing, zIndex),
                                minZoom, maxZoom, x, y, casingColor, width + (casingWidth * 2), lineJoin, dashes);
                        }
                        if (dashes == null)
                        { // dashes not set, use line offset.
                            scene.AddLine(this.CalculateSceneLayer(OffsetLine, zIndex),
                                minZoom, maxZoom, x, y, color, width, lineJoin, dashes);
                        }
                        else
                        { // dashes set, use line pattern offset.
                            scene.AddLine(this.CalculateSceneLayer(OffsetLinePattern, zIndex),
                                minZoom, maxZoom, x, y, color, width, lineJoin, dashes);
                        }

                        int textColor;
                        int fontSize;
                        string nameTag;
                        if (!rule.TryGetProperty("fontSize", out fontSize))
                        {
                            fontSize = 10;
                        }
                        if (rule.TryGetProperty("text", out nameTag) &&
                            rule.TryGetProperty("textColor", out textColor))
                        {
                            int haloColor;
                            int? haloColorNullable = null;
                            if (rule.TryGetProperty("textHaloColor", out haloColor))
                            {
                                haloColorNullable = haloColor;
                            }
                            int haloRadius;
                            int? haloRadiusNullable = null;
                            if (rule.TryGetProperty("textHaloRadius", out haloRadius))
                            {
                                haloRadiusNullable = haloRadius;
                            }
                            string name;
                            if (way.Tags.TryGetValue(nameTag, out name))
                            {
                                scene.AddTextLine(this.CalculateSceneLayer(OffsetLineText, zIndex),
                                    minZoom, maxZoom, x, y, textColor, fontSize, name, haloColorNullable, haloRadiusNullable);
                            }
                        }
                    }
                }
            }
        }
        /// <summary>
        /// Translates OSM objects into basic renderable primitives.
        /// </summary>
        /// <param name="scene">The scene to add primitives to.</param>
        /// <param name="projection">The projection used to convert the objects.</param>
        /// <param name="osmGeo">The osm object.</param>
        /// <returns></returns>
        public override void Translate(Scene2D scene, IProjection projection, CompleteOsmGeo osmGeo)
        {
            // set the scene backcolor.
            scene.BackColor = this.GetCanvasColor().Value;

            if (osmGeo == null) { return; }

            // store the object count.
            int countBefore = scene.Count;

            // interpret the osm-objects.
            switch (osmGeo.Type)
            {
                case CompleteOsmType.Node:
                    this.TranslateNode(scene, projection, osmGeo as CompleteNode);
                    break;
                case CompleteOsmType.Way:
                    this.TranslateWay(scene, projection, osmGeo as CompleteWay);
                    break;
                case CompleteOsmType.Relation:
                    this.TranslateRelation(scene, projection, osmGeo as CompleteRelation);
                    break;
                case CompleteOsmType.ChangeSet:
                    break;
                default:
                    throw new ArgumentOutOfRangeException();
            }

            // interpret the osmGeo object and check if it makes up an area.
            GeometryCollection collection = _geometryInterpreter.Interpret(osmGeo);
            foreach (Geometry geometry in collection)
            {
                if (geometry is LineairRing)
                { // a simple lineair ring.
                    this.TranslateLineairRing(scene, projection, geometry as LineairRing);
                }
                else if (geometry is Polygon)
                { // a simple polygon.
                    this.TranslatePolygon(scene, projection, geometry as Polygon);
                }
                else if (geometry is MultiPolygon)
                { // a multipolygon.
                    this.TranslateMultiPolygon(scene, projection, geometry as MultiPolygon);
                }
            }

            // check if any objects have been added to the scene.
            if (scene.Count <= countBefore)
            { // no objects have been added. Apply default styles if needed.
                if (osmGeo.Type == CompleteOsmType.Node &&
                    _mapCSSFile != null &&
                    _mapCSSFile.DefaultPoints)
                { // apply default points style.
                    CompleteNode node = (osmGeo as CompleteNode);
                    scene.AddPoint(this.CalculateSceneLayer(OffsetPoint, 0), float.MinValue, float.MaxValue,
                        projection.LongitudeToX(node.Coordinate.Longitude), projection.LatitudeToY(node.Coordinate.Latitude),
                        SimpleColor.FromKnownColor(KnownColor.Black).Value, 2);
                }
                else if (osmGeo.Type == CompleteOsmType.Way &&
                    _mapCSSFile != null &&
                    _mapCSSFile.DefaultLines)
                { // apply default lines style.
                    CompleteWay way = (osmGeo as CompleteWay);
                    // get x/y.
                    double[] x = null, y = null;
                    if (x == null)
                    { // pre-calculate x/y.
                        x = new double[way.Nodes.Count];
                        y = new double[way.Nodes.Count];
                        for (int idx = 0; idx < way.Nodes.Count; idx++)
                        {
                            x[idx] = projection.LongitudeToX(
                                way.Nodes[idx].Coordinate.Longitude);
                            y[idx] = projection.LatitudeToY(
                                way.Nodes[idx].Coordinate.Latitude);
                        }

                        // simplify.
                        if (x.Length > 2)
                        {
                            double[][] simplified = SimplifyCurve.Simplify(new double[][] { x, y }, 0.0001);
                            x = simplified[0];
                            y = simplified[1];
                        }
                    }
                    scene.AddLine(this.CalculateSceneLayer(OffsetLine, 0), float.MinValue, float.MaxValue,
                        x, y, SimpleColor.FromKnownColor(KnownColor.Red).Value, 1, LineJoin.Round, null);
                }
            }
        }