Different custom colors for a WPF line plot

Question

Dear Sir,
I am trying to create a WPF graph with different colors for different points of time , example  Black 0-10,red 11-20, green 21-30...
I saw the nifty video and download the range masking cursor but got stuck. 
Thank you
George MAsiello

Answer 1

Here's a quick mockup of the custom renderer version (sorry I did not have time to translate it to VB myself):
    public class CustomRenderer : PlotRenderer {
        private static readonly DataRequirements _dataRequirements = new DataRequirements(
            DataCulling.PreserveLines, DataDecimation.CoLinear,
            new DataDimension( DataDimensionSource.IndexData, DataDimensionScale.IndependentScale ),
            new DataDimension( DataDimensionSource.SampleData, DataDimensionScale.DependentScale ) );
        // The color ranges we want to show on the plot.
        private readonly Tuple<Color, double>[] _colorRanges = new[] {
            Tuple.Create( Colors.Black, 10.0 ),
            Tuple.Create( Colors.Red, 20.0 ),
            Tuple.Create( Colors.Green, 30.0 ),
        private readonly RenderTargetOptions[] _rangeOptions;
        public CustomRenderer( ) {
            // Create render options for each range color.
            _rangeOptions = _colorRanges.Select( colorRange => new RenderTargetOptions( this,
                RenderTargetOption.CreateValue( RenderTargetOptionsProperty.Stroke, new SolidColorBrush( colorRange.Item1 ) ),
                RenderTargetOption.CreateValue( RenderTargetOptionsProperty.StrokeThickness, 1.0 ) ) )
            .ToArray( );
        public override SupportedRenderModes SupportedRenderModes {
            get { return SupportedRenderModes.VectorAndRaster; }
        public override DataRequirements GetDataRequirements( ) {
            return _dataRequirements;
        protected override Freezable CreateInstanceCore( ) {
            return new CustomRenderer( );
        protected override void RenderLegendCore( LegendRenderArgs renderArgs ) { }
        protected override void RenderGraphCore( PlotRenderArgs renderArgs ) {
            // Get the time axis for the renderer.
            Plot plot = (Plot)renderArgs.Plot;
            var timeAxis = plot.GraphParent.GetAxis( plot, Orientation.Horizontal );
            var dataMapper = (IDataMapper<double>)timeAxis.GetDataMapper( plot.GraphParent );
            int startIndex = 0;
            var xData = renderArgs.RelativeData[0];
            var yData = renderArgs.RelativeData[1];
            var renderTarget = renderArgs.RenderTarget;
            for( int i = 0; i < _colorRanges.Length - 1; ++i ) {
                // Draw all data below the current range with the associated color.
                int endIndex = startIndex;
                double range = _colorRanges[i].Item2;
                double offset = dataMapper.Map( range );
                while( endIndex < xData.Size && xData[endIndex] <= offset )
                    ++endIndex;
                RenderSegment( startIndex, endIndex, xData, yData, renderTarget, _rangeOptions[i] );
                startIndex = endIndex;
            // Draw all remaining data with the last color range.
            RenderSegment( startIndex, xData.Size, xData, yData, renderTarget, _rangeOptions.Last( ) );
        private static void RenderSegment( int startIndex, int endIndex, Buffer<double> xData, Buffer<double> yData, IRenderTarget renderTarget, RenderTargetOptions options ) {
            int length = endIndex - startIndex;
            if( length <= 0 )
                return;
            // Join current range with previous.
            if( startIndex > 0 ) {
                --startIndex;
                ++length;
            using( Buffer<double> xSegment = xData.Slice( startIndex, length ) )
            using( Buffer<double> ySegment = yData.Slice( startIndex, length ) )
                renderTarget.DrawLines( options, xSegment, ySegment );
~ Paul H