c# - OxyPlot自动缩放

AutoScale OxyPlot图表。
例如，我有这样的事情。

using OxyPlot;
using OxyPlot.Axes;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using OxyPlot.Wpf;
using PlotControllerTest.Properties;
using System.Diagnostics;
namespace PlotControllerTest
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
///
public class Chart
{
    public PlotController myController { get; set; }
    private OxyPlot.Series.LineSeries LS;
    OxyPlot.Axes.LinearAxis LAY;
    OxyPlot.Axes.LinearAxis LAX;
    private int i = 0;
    public PlotModel PlotModel {get;set;}
    public Chart()
    {

        PlotModel = new PlotModel();
        myController = new PlotController();
        myController.UnbindAll();
        myController.BindMouseDown(OxyMouseButton.Left, OxyPlot.PlotCommands.PanAt);
        LS = new OxyPlot.Series.LineSeries();
        LAY = new OxyPlot.Axes.LinearAxis()
        {
            Position = OxyPlot.Axes.AxisPosition.Left,
            AbsoluteMaximum = 100,
            AbsoluteMinimum = 1,
        };
        LAX = new OxyPlot.Axes.LinearAxis()
        {
            Position = OxyPlot.Axes.AxisPosition.Bottom,
            AbsoluteMaximum = 200,
            AbsoluteMinimum = 1,
            MinorStep=5,
        };
        PlotModel.Series.Add(LS);
        PlotModel.Axes.Add(LAY);
        PlotModel.Axes.Add(LAX);
    }
    public void BeginAddPoints()
    {
        Random rnd = new Random();
        do
        {
            int temp=rnd.Next(1, 100);
            LS.Points.Add(new DataPoint( ++i,temp));
            System.Threading.Thread.Sleep(100);

            Update();
        } while (i<30);
        Update();
    }
    public void Update()
    {
        PlotModel.InvalidatePlot(true);
    }
}
public partial class MainWindow : Window
{
    Chart TChart;
    delegate void BeginUpdate();
    private Stopwatch stopwatch = new Stopwatch();
    private long lastUpdateMilliSeconds;
    public MainWindow()
    {

        TChart = new Chart();
        BeginUpdate BU = new BeginUpdate(TChart.BeginAddPoints);
        IAsyncResult result = BU.BeginInvoke(null,null);
        DataContext = TChart;
        CompositionTarget.Rendering += CompositionTargetRendering;
        InitializeComponent();
    }
    private void CompositionTargetRendering(object sender, EventArgs e)
    {
        if (stopwatch.ElapsedMilliseconds > lastUpdateMilliSeconds + 300)
        {
            TChart.Update();
        }
    }
}

}

XAML代码看起来像

<Window x:Class="PlotControllerTest.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:oxy="http://oxyplot.org/wpf"
    Title="MainWindow" Height="350" Width="525">
<Grid>
    <oxy:PlotView Model="{Binding PlotModel}" DefaultTrackerTemplate="{x:Null}" Controller="{Binding myController}"></oxy:PlotView>
</Grid>

拖动后如何实现Y轴的自动缩放？例如，当我在窗口中拖动图表时，仅出现一条线（（1,2,4，（4,4））。 Y轴将显示2到4。

最佳答案

首先，您将无法使用正在使用的控制器来进行任何缩放，因为它会阻止任何平移/缩放功能。默认情况下，在右键单击上平移，并在鼠标滚轮上缩放。同样，您在创建时的plotmodel将自动绘制所有点，因此无需重新缩放。但是，假设您有一种平移和缩放的方法，可以自动重新计算y轴上应具有的最大值，如下所示：

首先创建一个AdustYExtent方法：

private void AdjustYExtent(OxyPlot.Series.LineSeries lserie, OxyPlot.Axes.LinearAxis xaxis, OxyPlot.Axes.LinearAxis yaxis)
    {
        if (xaxis != null && yaxis != null && lserie.Points.Count() != 0)
        {
            double istart = xaxis.ActualMinimum;
            double iend = xaxis.ActualMaximum;

            var ptlist = lserie.Points.FindAll(p => p.X >= istart && p.X <= iend);

            double ymin = double.MaxValue;
            double ymax = double.MinValue;
            for (int i = 0; i <= ptlist.Count()-1; i++)
            {
                ymin = Math.Min(ymin, ptlist[i].Y);
                ymax = Math.Max(ymax, ptlist[i].Y);
            }

            var extent = ymax - ymin;
            var margin = extent * 0; //change the 0 by a value to add some extra up and down margin

            yaxis.Zoom(ymin - margin, ymax + margin);
        }
    }

首先要做的是找到适合当前所见XAxis范围的所有点并将它们存储在ptlist值中。然后迭代此列表并找到相应的max和min y。然后，您只需要将那些最大值和最小值应用于y轴即可。注意我用来允许在顶部和底部放置额外空间的边距值。

现在，您必须将此方法绑定到x轴的AxisChanged事件。在Chart（）中将轴添加到绘图之前，添加

LAX.AxisChanged += (sender, e) => AdjustYExtent(LS, LAX, LAY); ;

现在，它应该根据您的x轴自动缩放y轴。

关于c# - OxyPlot自动缩放，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/29608087/