ValueRangePalette zoom out issue

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ehdrnsep
Posts: 48
Joined: Mon Jan 12, 2015 6:52 am

ValueRangePalette zoom out issue

Post by ehdrnsep » Fri Jan 20, 2017 7:35 am

Hello..

It is displayed in green when zoom out.
When it is zoom out, the data appears to be incorrect.
Can not I show the palette precisely on the chart?
Attachments
zoom out
zoom out
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default
default
1.png (12.92 KiB) Viewed 7766 times

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ArctionPasi
Posts: 1365
Joined: Tue Mar 26, 2013 10:57 pm
Location: Finland

Re: ValueRangePalette zoom out issue

Post by ArctionPasi » Sun Jan 22, 2017 7:17 am

Hello,

the coloring of XY line is made screen-coordinate based. Therefore, when zooming out a lot, the other side of a thick line may have different color than the other. It is a limitation of the palette-coloring feature.

You may want to try if using series.CustomLinePointColoringAndShaping event works better for your purpose. The CustomLinePointColoringAndShaping assumes screen coordinates too. You can convert data point values to screen coordinates with yAxis.ValueToCoord method, and screen coordinates to values with yAxis.CoordToValue method. In the event, you can get color as series.ValueRangePalette.GetColorByValue().
LightningChart Support Team, PT

ehdrnsep
Posts: 48
Joined: Mon Jan 12, 2015 6:52 am

Re: ValueRangePalette zoom out issue

Post by ehdrnsep » Mon Jan 23, 2017 2:03 am

Thank you for answer.

I try used CustomLinePointColoringAndShaping event.
It works well.
How does "PaletteType.Uniform" apply when using the CustomLinePointColoringAndShaping event?
It seems to be "PaletteType.Gradient" by default.
I attach my sample code .

Code: Select all

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using Arction.WinForms.Charting;
using Arction.WinForms.Charting.SeriesXY;
using Arction.WinForms.Charting.Axes;
using System.Diagnostics;

namespace AboutCustomLinePointColoringAndShaping
{
    public partial class Form1 : Form
    {
        LightningChartUltimate chart;

        public Form1()
        {
            InitializeComponent();
            this.chart = new LightningChartUltimate();
            chart.BeginUpdate();
            chart.Dock = DockStyle.Fill;
            chart.ViewXY.XAxes[0].ValueType = AxisValueType.Number;
            var series = new PointLineSeries();

            //Quantity of points
            int pointCount = 501;
            //Data interval 
            const double xInterval = 0.1;
            SeriesPoint[] points = new SeriesPoint[pointCount];
            double x;
            //Generate some data

            for (int point = 0; point < pointCount; point++)
            {
                x = (double)point * xInterval;
                points[point].X = x;
                points[point].Y = 50.0 + 30.0 * Math.Sin(x / 5.0) + 1.0 * Math.Sin(x * 5.0) + 15.0 * Math.Cos(x);
            }

            series.Points = points;

            ValueRangePalette palette = new ValueRangePalette();
            palette.Steps.Clear();
            palette.Type = PaletteType.Uniform;
            
            palette.Steps.Add(new PaletteStep(palette, Color.White, 0));
            palette.Steps.Add(new PaletteStep(palette, Color.Red, 40));
            palette.Steps.Add(new PaletteStep(palette, Color.Blue, 70));
            palette.Steps.Add(new PaletteStep(palette, Color.Lime, 100));
            series.ValueRangePalette = palette;
            series.UsePalette = false;

            series.CustomLinePointColoringAndShaping += Series_CustomLinePointColoringAndShaping;
            chart.ViewXY.PointLineSeries.Add(series);
            chart.ViewXY.ZoomToFit();
            this.Controls.Add(chart);
            chart.EndUpdate();
        }

        private void Series_CustomLinePointColoringAndShaping(object sender, CustomLinePointColoringAndShapingEventArgs e)
        {
            Stopwatch sw = Stopwatch.StartNew();
            PointLineSeries series = (PointLineSeries)e.Series;

            AxisY axisY = series.OwnerView.YAxes[series.AssignYAxisIndex];
            AxisX axisX = series.OwnerView.XAxes[series.AssignXAxisIndex];
            PointFloat[] coords = e.Coords;
            double yValue;
            Color color;
            for (int i = 0; i < coords.Length; i++)
            {
                bool isFind = false;
                PointFloat point = coords[i];
                LineSeriesCoordinateSolveResult res = series.SolveYCoordAtXCoord((int)point.X);
                if (res.SolveStatus == LineSeriesSolveStatus.OK)
                {
                    yValue = series.Points[res.MinIndex].Y;
                    if (series.ValueRangePalette.GetColorByValue(yValue, out color))
                    {
                        e.Colors[i] = color.ToArgb();
                        isFind = true;
                    }
                }

                if (isFind == false)
                {
                    e.Colors[i] = series.LineStyle.Color.ToArgb();
                }
            }
            sw.Stop();
            Debug.WriteLine(sw.Elapsed.ToString());
        }
    }
}


ehdrnsep
Posts: 48
Joined: Mon Jan 12, 2015 6:52 am

Re: ValueRangePalette zoom out issue

Post by ehdrnsep » Mon Jan 23, 2017 4:40 am

I have confirmed that it changes according to ValueRangePalette.Type.
However, when "ValueRangePalette.Type = PaletteType.Uniform", a gradient effect occurs.
Attachments
123.png
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ArctionPasi
Posts: 1365
Joined: Tue Mar 26, 2013 10:57 pm
Location: Finland

Re: ValueRangePalette zoom out issue

Post by ArctionPasi » Mon Jan 23, 2017 8:06 am

When a sharp color change is required, you'll need to add two points with same coordinates. Blue and Red. Otherwise GPU interpolates colors between two coordinates.
LightningChart Support Team, PT