c# - WPF DynamicDataDisplay - 使用标记缓慢绘图

Question

在使用标记时，我很难等待 D3 中的 ChartPlotter 显示自己。当然，我正在尝试绘制 Gazillion 记录(好吧，700,000 条记录)。当只使用一条线时，一切都很好(20 秒左右)。使用标记时，我们说的是 5 分钟。这是 Not Acceptable 。

有什么想法吗？

这是我所做的，下面有解释。

public static string MakeSimplePlot(double[][] xData, double[][] yData, string[] legend, string xAxisTitle, string yAxisTitle, bool[] showLines, bool[] showMarkers)
    {
        ChartPlotter plotter = new ChartPlotter();

        plotter.MainHorizontalAxis = new HorizontalAxis();
        plotter.MainVerticalAxis = new VerticalAxis();

        HorizontalAxisTitle horizontalAxisTitle = new HorizontalAxisTitle();
        horizontalAxisTitle.Content = xAxisTitle;
        plotter.AddChild(horizontalAxisTitle);

        VerticalAxisTitle verticalAxisTitle = new VerticalAxisTitle();
        verticalAxisTitle.Content = yAxisTitle;
        plotter.AddChild(verticalAxisTitle);

        Color[] plotColors = new Color[13] { Colors.Blue, Colors.Red, Colors.Green, Colors.Chartreuse, Colors.Yellow, Colors.Violet, Colors.Tan, Colors.Silver, Colors.Salmon, Colors.Lime, Colors.Brown, Colors.Chartreuse, Colors.DarkGray };

        for (int seriesCounter = 0; seriesCounter < legend.Count(); seriesCounter++)
        {
            DataFile clearedInputs = ClearExcess(new DataFile(xData[seriesCounter], yData[seriesCounter]));
            xData[seriesCounter] = clearedInputs.time;
            yData[seriesCounter] = clearedInputs.data;

            var xDataSource = new EnumerableDataSource<double>(xData[seriesCounter]);
            xDataSource.SetXMapping(x => x);

            var yDataSource = new EnumerableDataSource<double>(yData[seriesCounter]);
            yDataSource.SetYMapping(x => x);

            CompositeDataSource plotSeries = new CompositeDataSource(xDataSource, yDataSource);

            CirclePointMarker circlePointMarker = new CirclePointMarker();
            circlePointMarker.Fill = new SolidColorBrush(plotColors[seriesCounter]);
            circlePointMarker.Pen = new Pen(circlePointMarker.Fill, 0);

            circlePointMarker.Size = (showMarkers[seriesCounter] == false) ? 0 : 8;
            int lineWidth = (showLines[seriesCounter] == false) ? 0 : 2;

            if (showMarkers[seriesCounter] == false)
            {
                plotter.AddLineGraph(plotSeries, new Pen(circlePointMarker.Fill, lineWidth), new PenDescription("Dummy"));
            }
            else
            {
                plotter.AddLineGraph(plotSeries, new Pen(circlePointMarker.Fill, lineWidth), circlePointMarker, new PenDescription("Dummy"));
            }
        }

        UIParameters.plotWindow.mainGrid.Children.Clear();
        UIParameters.plotWindow.mainGrid.RowDefinitions.Clear();
        UIParameters.plotWindow.mainGrid.Children.Add(plotter);
        plotter.Viewport.FitToView();

        plotter.LegendVisible = false;
        plotter.NewLegendVisible = false;            

        if (legend.Count() > 1)
        {
            ShowLegend(legend, plotColors);
        }

        UIParameters.plotWindow.WindowState = WindowState.Minimized;
        UIParameters.plotWindow.WindowState = WindowState.Normal;

        string filename = Path.ChangeExtension(Path.GetTempFileName(), "png");

        RenderTargetBitmap targetBitmap = new RenderTargetBitmap((int)UIParameters.plotWindow.mainGrid.ActualWidth, (int)UIParameters.plotWindow.mainGrid.ActualHeight, 96d, 96d, PixelFormats.Default);
        targetBitmap.Render(UIParameters.plotWindow.mainGrid);
        PngBitmapEncoder encoder = new PngBitmapEncoder();
        encoder.Frames.Add(BitmapFrame.Create(targetBitmap));
        using (var fileStream = File.Open(filename, FileMode.OpenOrCreate))
        {
            encoder.Save(fileStream);
            UIParameters.plotWindow.mainGrid.Clip = null;

            GC.Collect();
            GC.WaitForPendingFinalizers();
            GC.Collect();

            targetBitmap.Freeze();

            if (targetBitmap != null) targetBitmap.Clear();
            targetBitmap = null;
            GC.Collect();
            GC.WaitForPendingFinalizers();

            GC.Collect();
            GC.WaitForPendingFinalizers();
        }

        return filename;
    }

解释:

1. 我隐藏绘图仪图例并使用 ShowLegend 制作我自己的图例，因为图例不会显示是否只有标记(我错了吗？)
2. 我最小化和最大化绘图窗口，否则绘图不会更新，或者它更新但不会保存到文件中。如果我移动窗口(我猜是某种重绘事件)，这也有效，但由于该过程是自动的，因此用户没有任何交互。我尝试使无效，但无济于事。想法？

谢谢!

Answer 1

我编写了自己的类来隐藏屏幕外的标记。当屏幕上没有大量标记时，这是一种虚拟化技术，可以将性能提高十倍。它看起来像这样:

using System;
using System.Windows;
using System.Windows.Media;
using Microsoft.Research.DynamicDataDisplay.DataSources;
using Microsoft.Research.DynamicDataDisplay.PointMarkers;
using Microsoft.Research.DynamicDataDisplay.Common;

namespace Microsoft.Research.DynamicDataDisplay.Charts {
public class FilteredMarkerPointsGraph : MarkerPointsGraph {
    public FilteredMarkerPointsGraph()
        : base() {
        ;
    }

    public FilteredMarkerPointsGraph(IPointDataSource dataSource)
        : base(dataSource) {
        ;
    }

    protected override void OnRenderCore(DrawingContext dc, RenderState state) {
        // base.OnRenderCore
        if (DataSource == null) return;
        if (Marker == null) return;

        var left = Viewport.Visible.Location.X;
        var right = Viewport.Visible.Location.X + Viewport.Visible.Size.Width;
        var top = Viewport.Visible.Location.Y;
        var bottom = Viewport.Visible.Location.Y + Viewport.Visible.Size.Height;

        var transform = Plotter2D.Viewport.Transform;

        DataRect bounds = DataRect.Empty;
        using (IPointEnumerator enumerator = DataSource.GetEnumerator(GetContext())) {
            Point point = new Point();
            while (enumerator.MoveNext()) {
                enumerator.GetCurrent(ref point);                                       

                if (point.X >= left && point.X <= right && point.Y >= top && point.Y <= bottom)
                {
                    enumerator.ApplyMappings(Marker);

                    Point screenPoint = point.DataToScreen(transform);

                    bounds = DataRect.Union(bounds, point);
                    Marker.Render(dc, screenPoint);
                }
            }
        }

        Viewport2D.SetContentBounds(this, bounds);
    }
}

确保在 XAML 中调用 FilteredMarkerPointsGraph 而不是 MarkerPointsGraph!

编辑

1. 我不确定您需要什么带标记的图例，我实际上没有在我的任何图表中使用过图例，但您的解决方案似乎没问题。

2. 重绘剧情其实很容易。

我发现执行此操作的最佳方法是在您的代码后面有一个表示数据源的属性，并将图表的数据源绑定(bind)到该属性。每次更新或重新分配数据源时，让您的代码实现 INotifyPropertyChanged 并调用 OnPropertyChanged。这将强制绘图仪观察绑定(bind)并重新绘制图形。

例子:

EnumerableDataSource<Point> m_d3DataSource;
public EnumerableDataSource<Point> D3DataSource {
get {
    return m_d3DataSource;
}
set {                
    //you can set your mapping inside the set block as well             
    m_d3DataSource = value;
    OnPropertyChanged("D3DataSource");
}
}     

protected void OnPropertyChanged(PropertyChangedEventArgs e) {
    PropertyChangedEventHandler handler = PropertyChanged;
    if (handler != null) {
        handler(this, e);
    }
} 

protected void OnPropertyChanged(string propertyName) {
    OnPropertyChanged(new PropertyChangedEventArgs(propertyName));
}  

关于您使用标记的表现。很难准确指出是什么导致了您的表现问题，但我的建议是尝试使用不同的数据源。我一直在使用 EnumerableDataSource 并且它总是非常有效。尝试将您的数据引入单个对象并在您的 set block 中设置映射，如上所示使用:

value.SetYMapping(k => Convert.ToDouble(k.yData));
value.SetXMapping(k => Convert.ToDouble(k.xData));

您唯一需要担心的是 Enumerable 数据源中的映射，D3 应该会为您处理剩下的事情。