Hi Plamen,
Yes, the following code snippet shows how to create a simple line chart that is populated with data according to the current zoom range:
using System;
using System.Windows.Forms;
using Nevron.Chart;
using Nevron.Chart.WinForm;
using Nevron.GraphicsCore;
namespace WindowsFormsApplication22
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
double[] Values;
double[] XValues;
NLineSeries Line;
NCartesianChart Chart;
private void Form1_Load(object sender, EventArgs e)
{
Values = new double[100000];
XValues = new double[100000];
Random rand = new Random();
for (int i = 0; i < Values.Length; i++)
{
Values[i] = 500 + 500 * Math.Sin(i / 10000.0);
XValues[i] = i;
}
NChartControl1.Document.RootPanel.ChildPanels.Clear();
// create a simple header
NLabel header = new NLabel("Some Header Text");
header.Margins = new NMarginsL(10, 10, 10, 10);
header.Dock = DockStyle.Top;
NChartControl1.Panels.Add(header);
Chart = new NCartesianChart();
NRangeSelection rs = new NRangeSelection();
rs.VerticalValueSnapper = new NAxisRulerMinMaxSnapper();
Chart.RangeSelections.Add(rs);
NChartControl1.Panels.Add(Chart);
// associate chart with the legend
Chart.Dock = DockStyle.Fill;
Chart.Margins = new NMarginsL(10, 0, 10, 10);
Chart.BoundsMode = BoundsMode.Stretch;
Line = new NLineSeries();
Line.DataLabelStyle.Visible = false;
Line.SamplingMode = SeriesSamplingMode.Enabled;
Line.UseXValues = true;
Chart.Series.Add(Line);
NOrdinalScaleConfigurator scale = Chart.Axis(StandardAxis.PrimaryX).ScaleConfigurator as NOrdinalScaleConfigurator;
scale.RoundToTickMax = false;
scale.RoundToTickMin = false;
Chart.Axis(StandardAxis.PrimaryX).ScrollBar.Visible = true;
Chart.Axis(StandardAxis.PrimaryX).View = new NRangeAxisView(new NRange1DD(0, Values.Length), true, true);
Chart.Axis(StandardAxis.PrimaryY).View = new NRangeAxisView(new NRange1DD(0, 1000), true, true);
Chart.PaintCallback = new NCustomPaintCallback(this);
NChartControl1.Controller.Selection.Clear();
NChartControl1.Controller.Selection.SelectedObjects.Add(Chart);
NChartControl1.Controller.Tools.Add(new NAxisScrollTool());
NDataZoomTool dzt = new NDataZoomTool();
NChartControl1.Controller.Tools.Add(dzt);
}
class NCustomPaintCallback : NPaintCallback
{
Form1 Form;
public NCustomPaintCallback(Form1 form)
{
Form = form;
}
public override void OnBeforePaint(NPanel panel, NPanelPaintEventArgs eventArgs)
{
NRange1DD range = Form.Chart.Axis(StandardAxis.PrimaryX).Scale.RulerRange;
int count = Form.Line.XValues.Count;
if (count > 0)
{
if (((double)Form.Line.XValues[0] == (int)range.Begin &&
(double)Form.Line.XValues[count - 1] == (int)range.End))
{
return;
} }
Form.Line.Values.Clear();
Form.Line.XValues.Clear();
int length = (int)Math.Round(range.End - range.Begin);
double[] yValues = new double[length];
double[] xValues = new double[length];
Array.Copy(Form.Values, (int)range.Begin, yValues, 0, length);
Array.Copy(Form.XValues, (int)range.Begin, xValues, 0, length);
Form.Line.Values.AddRange(yValues);
Form.Line.XValues.AddRange(xValues);
Form.NChartControl1.Document.Calculate();
Form.NChartControl1.Refresh();
}
}
}
}
The idea is simple:
1. You have to fix the view ranges on both the x and y axes. In the code above this is done by:
Chart.Axis(StandardAxis.PrimaryX).View = new NRangeAxisView(new NRange1DD(0, Values.Length), true, true);
Chart.Axis(StandardAxis.PrimaryY).View = new NRangeAxisView(new NRange1DD(0, 1000), true, true);
2. Then on before paint the code checks the current zoom range of the x axis and populates the data for that range in the line values and xvalues arrays
Hope this helps.