I am having trouble getting the heatmap to save to SVG. Axes, legend, and labels show but no heatmap itself. Any thoughts?

Nevermind. Just updated to the latest code base and looks like it was fixed.

Hi everybody,

I'm currently blocked by an issue that is I want to get a list of screen points from the list of data points. My list of data points is filled and is valued but when I apply a tranform to get screen points, the result is always 0,0 per each point. Can you tell me why?

Here is my code :

foreach (DataPoint dp in series.Points)
{
      Console.WriteLine(dp);
      Console.WriteLine(this.xAxis.Transform(dp.X, dp.Y, this.yAxis));
}

And the result in console :

41695 1.3715
0 0
41696 1.3697
0 0
41697 1.37545
0 0
41700 1.37595
0 0
41701 1.37375
0 0
41702 1.3737
0 0
41703 1.37945
0 0
41704 1.3867
0 0
41707 1.3875
0 0
41708 1.38665
0 0
41709 1.3881
0 0
41710 1.3885
0 0
41711 1.389
0 0
41714 1.39145
0 0
41715 1.39265
0 0
41716 1.3882
0 0
41717 1.38045
0 0
41718 1.3784
0 0
41721 1.38145
0 0
41722 1.3831
0 0
41723 1.3803
0 0
41724 1.37595
0 0
41725 1.37455
0 0
41728 1.3762

I made this after giving model to the plot view and after adding series. I add that my x axis is a DateTime axis and my Y axis is a linear axis.

Finally I need to get the real points coordonates.

Thank's for help.

The transforms on the axes are defined when rendering (since they depend on the width/height of the client area). Are you trying to transform before the plot is rendered? Maybe you can subscribe to the Axis.TransformChanged event and do this after the transform has been set?

Hi objo,
I started to use oxyplot not long ago, thanks for the great library.
While developing I traced into oxyplot source and make some changes. Need to know if the changes are good, and could it be included into official trunk?

1. Added "Resolution" properties to LineSeries to give option on lower resolution drawing in high data count use case.
   
2. BoxPlotSeries GetNearestPoint TrackerHitResult.Text should return DateTime for DateTimeAxis.
   

 -                            result.DataPoint.X,
+                            this.XAxis != null ? this.XAxis.GetValue(result.DataPoint.X) : result.DataPoint.X,

1. RenderingExtension DrawClippedLine exception when trying to draw a line with single point. So I added a check for single point case and create an offset just like what the code did in latter single point case. Not sure if this is the best way.

// render the line if we are leaving the clipping region););
                    if (!clipping.IsInside(s1))
                    {
                        if (pts.Count > 0)
                        {
                          // Check if the line contains a single point
                          if (pts.Count == 1) {
                            // Add a second point to make sure the line is being rendered as a small dot
                            pts.Add(new ScreenPoint(pts[0].X + 1, pts[0].Y));
                            pts[0] = new ScreenPoint(pts[0].X - 1, pts[0].Y);
                          }

                            rc.DrawLine(
                                pts, stroke, strokeThickness, lineStyle.GetDashArray(), lineJoin, aliased);
                            if (pointsRendered != null)
                            {
                                pointsRendered(pts);
                            }

                            pts = new List<ScreenPoint>();
                        }
                    }

thanks for the bug reports and correction code! I have corrected #2 and #3, and added examples to make sure it works.
How did you implement lower resolution in #1? The LineSeries has a MinimumSegmentLength property that works in screen coordinates.
Are you sampling the input data points - I think this could be handled by the application, not by the plotting library.

Hi objo,
Thanks for the updated code, your changes are much elegant by moving the single point handling to a separate method.

As for #1 (resolution), I simply added a Resolution property to LineSeries and pass it along to RenderingExtensions.DrawMarkers.

            if (this.MarkerType != MarkerType.None)
            {
                rc.DrawMarkers(
                    pointsToRender, 
                    clippingRect, 
                    this.MarkerType, 
                    this.MarkerOutline, 
                    new[] { this.MarkerSize }, 
                    this.MarkerFill, 
                    this.MarkerStroke, 
                    this.MarkerStrokeThickness,
                    this.Resolution); // added Resolution property and pass it to draw markers
            }

Some background on my intention: I realize the 100K performance test is only good for non-markers line series. When there is markers, the performance degraded drastically due to markers drawing, obviously markers drawing requires much heavier processing than simple line drawing. Hence I try to reduce the number of markers when they overlapped, which is what DrawMarkers resolution argument is doing. Honestly the resolution method that I use (resolution 5) is just slight better than the original code, still not good enough for my application but I will look at possible way to improve that later.


I was considering handling in application code, but found DrawMarkers method to be resolution capable, so i just reuse it. After take a look at MinimumSegmentLeght, it is mainly to optimize line drawing, the markers drawing is not affected by this property, if I read it correctly... But I do see that I can use ScreenPointHelper.ResamplePoints to get resample screenpoints and pass it to DrawMarkers, what do you think?

ok, I added a MarkerResolution property to the LineSeries.
Note: the last argument of the DrawMarkers method should also be provided when using the resolution argument (otherwise you will get marker flickering when panning)

Thanks objo, that works great!

I would like to show multiple independent plots using a listbox. I have a collection of PlotModels (collection derives from ObservableCollection) as my resource and ItemsSource for the ListBox. I set the ItemTemplate of the ListBox to a DataTemplate containing just the Plot control binding Model to the item. The PlotModels are initialized in the Window constructor in code behind. Rather than seeing the Plot at runtime, there is blank space. If I take the Plot out of the ListBox, it works fine on its own.

Is this possibly related to this issue? DataTemplate Issue

This sounds like a bug, and I guess it is related to the DataTemplate issue.
Can you try to turn off virtualization in the ListBox control?
Does the same thing happen if you use an ItemsControl?
Can you create a small example we can use to test (I know it only takes 10min... :-)

The XAML:

<Window x:Class="WpfApplication1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:oxy="clr-namespace:OxyPlot.Wpf;assembly=OxyPlot.Wpf"
        xmlns:local="clr-namespace:WpfApplication1"
        Title="MainWindow" Height="350" Width="525">
  <Window.Resources>
    <local:PlotCollection x:Key="Plots" />
  </Window.Resources>
  <ListBox ItemsSource="{DynamicResource Plots}" ScrollViewer.CanContentScroll="False"
           VirtualizingStackPanel.IsVirtualizing="False">
    <ListBox.ItemTemplate>
      <DataTemplate>
        <oxy:Plot Model="{Binding}" />
      </DataTemplate>
    </ListBox.ItemTemplate>
  </ListBox>
</Window>

Additional code:

  public class PlotCollection : System.Collections.ObjectModel.ObservableCollection<OxyPlot.PlotModel> {
    public PlotCollection() {
      this.Add(new OxyPlot.PlotModel("Title 0"));
      this.Add(new OxyPlot.PlotModel("Title 1"));
      this.Add(new OxyPlot.PlotModel("Title 2"));
      this[0].Series.Add(new OxyPlot.Series.LineSeries("Series 0"));
      this[1].Series.Add(new OxyPlot.Series.LineSeries("Series 1"));
      this[2].Series.Add(new OxyPlot.Series.LineSeries("Series 2"));
      (this[0].Series[0] as OxyPlot.Series.LineSeries).Points.Add(
        new OxyPlot.DataPoint(0, 0));
      (this[0].Series[0] as OxyPlot.Series.LineSeries).Points.Add(
        new OxyPlot.DataPoint(1, 1));
      (this[1].Series[0] as OxyPlot.Series.LineSeries).Points.Add(
        new OxyPlot.DataPoint(0, 0));
      (this[1].Series[0] as OxyPlot.Series.LineSeries).Points.Add(
        new OxyPlot.DataPoint(1, 1));
      (this[2].Series[0] as OxyPlot.Series.LineSeries).Points.Add(
        new OxyPlot.DataPoint(0, 0));
      (this[2].Series[0] as OxyPlot.Series.LineSeries).Points.Add(
        new OxyPlot.DataPoint(1, 1));
    }
  }

Thanks for the code!
I think you have to set the height of the plot control. But there is also something else that must be done...
It works for ItemsControl, but I am not sure why it doesn't for a ListBox.

The height requirement makes sense, it needs something to determine the size. I'm at a loss concerning the ListBox, but I think the ItemsControl will be good enough for what I needed.

I am working on an Android app using MonoDroid. I am in need of a good plotting library, and I have used OxyPlot in my WPF apps before, so I came to check if there was a MonoDroid version - and indeed there is.

I know it is an "alpha", so I was wondering what known limitations and bugs it has, just so I can be aware of them as I start trying to integrate it into my project?