How hide labels? about livecharts2

[beto-rodriguez]

the empty space is not caused by the axis, it is caused by the series, notice all the series have a blank distance between the start of the axis and the first point of the series.

Series.DataPadding should do the trick, docs are not ready yet, but you can try something like:

new LineSeries<int> 
{ 
    Values = new []{ 1, 5, 4, 2, 7, 4, 6, 8 },
    DataPadding = new System.Drawing.PointF(0, 1)
}

for both X and Y axes: 0 means nothing, 1 means the Axis tick, an Axis tick is the distance between the labels in the axis (even if there are not visible labels, the tick is calculated).

[FanIT]

@beto-rodriguez thank you. It's works great. And thank for continuing the project.

[beto-rodriguez]

I have also seen this issue, I am not sure yet, but I think this is an Avalonia issue.

The problem is when the chart clears the canvas with a transparent color, Avalonia has not drawn anything behind our chart control, then we get this result.

The workaround I built for the library, is that based on the Background color of the chart I pull a color to clear the canvas:

This is the workaround, and it is not working in your case because it was not able to build a color from null, just set a color for now, or open an issue in Avalonia, I am not completely sure yet, but I am almost sure that the issue is theirs.
https://github.com/beto-rodriguez/LiveCharts2/blob/master/src/skiasharp/LiveChartsCore.SkiaSharp.Avalonia/CartesianChart.axaml.cs#L325

[FanIT]

@beto-rodriguez
I would wantn't to open a new issue, but i have a question.
I set Background="{x:Null}" for CartesianChart to achieve a background of my window, but the CartesianChart is ignoring backround of the window and becomes completely transparent. I need to get the translucent, black background.

<Window xmlns="https://github.com/avaloniaui"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:lvc="using:LiveChartsCore.SkiaSharpView.Avalonia"
        xmlns:cm="using:AvaloniaTest"
        mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
        x:Class="AvaloniaTest.MainWindow" Title="AvaloniaTest" TransparencyLevelHint="AcrylicBlur" Background="{x:Null}">
    <Window.DataContext>
        <cm:ChartModel />
    </Window.DataContext>
    <Grid>
        <Rectangle Fill="Black" Stroke="Black" Opacity="0.7" />
        <lvc:CartesianChart Series="{Binding Series}" XAxes="{Binding YAxis}"
                            YAxes="{Binding XAxis}" IsHitTestVisible="False"
                            Background="{x:Null}">
      </lvc:CartesianChart>
    </Grid>
</Window>

Without CartesianChart

With CartesianChart

[FanIT]

Thanks for answered. I solved the problem by setting a color with alpha-canal.

CartesianChart cartesianChart = this.FindControl<CartesianChart>("CartesianChart");
cartesianChart.Background = new SolidColorBrush(new Color(128,0, 0, 0));

[FanIT]

@beto-rodriguez, sorry. I have one more question.
I'm using LiveChart 2 for real time chart and watching a memory leak and increasing cpu load.
I'm add a new ObservablePoint and remove a first in a ObservableCollection every second.
Should i somehow clearing CartesianChart or do some other an actions for to free the memory?

[beto-rodriguez]

it should be handled automatically by tue library, let me try to reproduce

[beto-rodriguez]

Thanks for the report again @FanIT I found 2 issues, one that was affecting all the platforms, and another one that was an Avalonia specific issue, you were facing both in your case.

Please let me know if everything is working properly now.

fixed somewhere in 387892f

[FanIT]

I builded LiveChartsCore.SkiaSharpView.dll and LiveChartsCore.SkiaSharpView.Avalonia.dll from fresh source code and tested with JetBrains dotMemory.
I still watching a memory leak.
Total used:
Start - 51.4 mb
10 minutes - 80.9 mb
20 minutes - 114.3 mb
30 minutes - 150.8 mb
40 minutes - 180.5 mb
50 minutes - 215.6 mb
End - Total used 291.7 mb, Heap generation 2 - 235 mb.
Maybe i'm doing something wrong?
I can provide my test code or any required data.
My chart model.

class ChartModel
    {
        private Random random;
        private int index = 0;

        public ObservableCollection<ObservablePoint> observableValues { get; set; }

        public ChartModel()
        {
            random = new Random();

            observableValues = new();

            for (byte b = 0; b < 50; b++)
            {
                observableValues.Add(new ObservablePoint(index++, b));
            }

            Series = new ObservableCollection<ISeries>
            {
                new LineSeries<ObservablePoint>
                {
                    Values = observableValues,
                    Fill = new SolidColorPaintTask(SKColors.Blue),
                    Stroke = null,
                    GeometryFill = null,
                    GeometryStroke = null,
                    DataPadding = new PointF(0, 1)
                }
            };
        }

        public void Add()
        {
            observableValues.RemoveAt(0);
            observableValues.Add(new ObservablePoint(index++, random.NextDouble()));
        }

        public ObservableCollection<ISeries> Series { get; set; }

        public List<Axis> XAxis { get; set; } = new List<Axis>
        {
            new Axis
            {
                IsVisible = false
            }
        };

        public List<Axis> YAxis { get; set; } = new List<Axis>
        {
            new Axis
            {
                IsVisible = false
            }
        };
    }

[beto-rodriguez]

OK I'll keep investigating.

[beto-rodriguez]

@FanIT How are you calling the Add method, I just tested the AvaloniaSample project, in the lines AutomaticUpdates sample, just clicked on "Constant changes", this sample is similar to the code you shared, I see no memory leak after 30 mins running.

I will let it more time running, and will document my results here, but at first instance I think that the issue is gone.

[beto-rodriguez]

50 mins running, no memory leak found, tested with dot memory 2021.1

[FanIT]

Many thanks you and sorry. Probably the problem was in Avalonia. I updated to Avalonia 0.10.4 and no longer see the memory leak.
I'm calling Add in DispatcherTimer of Avalonia.Threading a every second.

Avalonia.Threading.DispatcherTimer timer = new DispatcherTimer();
            timer.Interval = new TimeSpan(0, 0, 1);
            timer.Tick += (object? sender, EventArgs e) => { chart.Add(); };
            timer.Start();

I tested 1 hour and every 10 minutes doing snapshot.