// Read:
CtbFile ctb = new CtbFile("input.ctb"); 
// Write:
ctb.WriteTo("output.ctb");

    /// <summary>
    /// Example for using different colors for some color indexes.
    /// </summary>
    public class IndexedColorExchanger {
        private readonly IDictionary<short, ArgbColor> indexToColorMapping;

        /// <summary>
        /// Initializes a new instance of the <see cref="IndexedColorExchanger"/> class.
        /// </summary>
        /// <param name="colorMap">The color map, which only contains the colors indexes to be exchanged.</param>
        public IndexedColorExchanger(IDictionary<short, ArgbColor> colorMap) {
            indexToColorMapping = colorMap;
        }

        /// <summary>
        /// Gets the plot style.
        /// </summary>
        /// <remarks>This method can be used as a <see cref="GraphicsConfig.PlotStyleManager"/>.</remarks>
        /// <param name="plotPropertyOwner">The plot property owner (usually an entity).</param>
        /// <param name="drawContext">The draw context.</param>
        /// <returns>The plot style.</returns>
        public IPlotStyle GetPlotStyle(IPlotPropertyOwner plotPropertyOwner, DrawContext drawContext) {
            EntityColor entityColor = plotPropertyOwner.GetEntityColor(drawContext);
            if (entityColor.ColorType == ColorType.ByColorIndex) {
                ArgbColor substitutionColor;
                if (indexToColorMapping.TryGetValue(entityColor.ColorIndex, out substitutionColor)) {
                    return new OverrideColorPlotStyle(substitutionColor, plotPropertyOwner, drawContext);
                }
            }
            return new DefaultPlotStyle(plotPropertyOwner, drawContext);
        }
    }

    /// <summary>
    /// Plot manager class allowing to exchange line weights by color index.
    /// </summary>
    /// <remarks>
    /// Use <see cref="ApplyLineWeightPlotting"/> how to prepare any 
    /// <see cref="GraphicsConfig"/> to use exchanged line weights.
    /// </remarks>
    public class LineWeightChanger {
        private readonly IDictionary<short, short> indexToLineWeightMapping;

        /// <summary>
        /// Initializes a new instance of the <see cref="LineWeightChanger"/> class.
        /// </summary>
        /// <param name="indexToLineWeightMapping">
        /// The exchanged line weights.
        /// Keys are color indices, values are exchanged line weights in 100th of mm.
        /// If a color index is not present in this map, the entity's effective line weight is taken.
        /// </param>
        public LineWeightChanger(IDictionary<short, short> indexToLineWeightMapping) {
            this.indexToLineWeightMapping = indexToLineWeightMapping;
        }

        /// <summary>
        /// Gets the plot style.
        /// </summary>
        /// <remarks>This method can be used as a <see cref="GraphicsConfig.PlotStyleManager"/>.</remarks>
        /// <param name="plotPropertyOwner">The plot property owner (usually an entity).</param>
        /// <param name="drawContext">The draw context.</param>
        /// <returns>The plot style.</returns>
        public IPlotStyle GetPlotStyle(IPlotPropertyOwner plotPropertyOwner, DrawContext drawContext) {
            EntityColor entityColor = plotPropertyOwner.GetEntityColor(drawContext);
            if (entityColor.ColorType == ColorType.ByColorIndex) {
                short substitutionLineWeight;
                if (indexToLineWeightMapping.TryGetValue(entityColor.ColorIndex, out substitutionLineWeight)) {
                    switch (substitutionLineWeight) {
                        case LineWeight.ByBlock:
                            substitutionLineWeight = drawContext.ByBlockLineWeight;
                            break;
                        case LineWeight.ByLayer:
                            DxfLayer layer = plotPropertyOwner.GetLayer(drawContext);
                            substitutionLineWeight = layer.GetLineWeight(drawContext.Config);
                            break;
                        case LineWeight.Standard:
                            substitutionLineWeight = drawContext.Config.DefaultLineWeight;
                            break;
                    }
                    return new OverrideLineWeightPlotStyle(substitutionLineWeight, plotPropertyOwner, drawContext);
                }
            }
            return new DefaultPlotStyle(plotPropertyOwner, drawContext);
        }

        /// <summary>
        /// Prepare a graphics configuration which uses line weight mapping.
        /// </summary>
        /// <param name="config">The graphics configuration, unchanged.</param>
        /// <param name="indexToLineWeightMapping">Line weight mapping to use.</param>
        /// <return>Clone of <paramref name="config"/>, prepared to exchange line weights.</return>
        public static GraphicsConfig ApplyLineWeightPlotting(GraphicsConfig config, IDictionary<short, short> indexToLineWeightMapping) {
            LineWeightChanger changer = new LineWeightChanger(indexToLineWeightMapping);
            GraphicsConfig result = (GraphicsConfig)config.Clone();
            result.PlotStyleManager = changer.GetPlotStyle;
            return result;
        }
    }