Category: JavaScript

How to display data labels vertically and support Chinese，As shown in Fig

Hello, how do I remove the shadow from tooltips, generated by the VerticalSliceModifier?

Thanks!

Good evening. Lately I’ve been troubleshooting a problem with page memory usage increasing. Over time, the memory grows exponentially and reaches several gigabytes. To explain the problem, we need to describe how we use charts:

On our website in real time, depending on our algorithm, the charts replace each other. The user constantly sees 4 charts, which are constantly replaced by others. Adding new charts occurs unnoticed by the user and only after the graph is fully loaded and drawn does it replace the previous one. That is, the user actually sees 4 charts, but there may be more on the page. After replacing the desired chart, the old one is deleted using surface.delete() and removing all dependencies.

At first, when creating a chart, I used the create() method. After a number of attempts to avoid memory accumulation and re-reading the documentation, I came to the conclusion that it is possible, since all graphs are created using create() – they have a common wasm and since there cannot be a situation in which all charts will be deleted (at least 4 are always present ), then wasm memory is not freed. Tell me if I’m right about this.

Afterwards, I decided to try to create charts using createSingle() with a reliable method, which now, since each graph has its own wasm, memory will be freed. Perhaps this was the case, but I can’t say for sure, because now after some time the page began to reload automatically with the appearance of an error, the screenshot of which I attached. This is most likely due to a wasm limitation on the page when using createSingle. Although it’s strange, when you delete the chart, the amount of wasm should decrease. And even with a limit of 16 copies, this should be enough. Please explain this error to me as well, perhaps the problem with rebooting can be somehow solved by you (I’m not sure that this should happen)

Thank you very much in advance for your answer. Have a good day!

This demo was very helpful in working export out. I have a followup question. For a specific user request, I’m currently attempting something along these lines (current state; there’s some spaghetti-against-the-wall method going on at the moment):

const previousTheme = surface.themeProvider;

    const exportTheme = {
        ...previousTheme,
        sciChartBackground:"Transparent",
        gridBackgroundBrush:"Transparent",
        axisBandsFill: "Transparent"
    }

    surface.applyTheme(exportTheme);
    surface.background = "Transparent";

    new Promise(r => setTimeout(r, 1000)).then(() => {
        try {
            const node = document.getElementById('scichart-stuff');
            if (!node)
                return;
            domtoimage
                .toPng(node )
                .then(function (blob) {
                    saveAs(blob, 'plot.png');
                })
                .catch(function (error) {
                    console.error('Problem exporting/saving image of plot', error);
                });
        } finally {
            surface.applyTheme(previousTheme);
        }
    })

I am able to see the update (after adding the delay) on the screen, but the export appears to be ignoring the values I’m setting. I’m wondering what I might be missing in terms of the interactions of these libraries.

I’m a C# developer looking to evaluate working with SciChartJS for a possible future project.

I’ve created a .NET Blazor Project working with JavaScript Interop and I would like to extend the CustomChartModifier2D in TypeScript.

I’ve not used npm to install SciChart into the project, rather I’m using the CDN approach in my _Host.cshtml file.

<script src="https://cdn.jsdelivr.net/npm/[email protected]/index.min.js" crossorigin="anonymous"></script>

I’ve been searching online for a SciChartJS TypeScript definition file so that I can leverage TS Strongly Typed system in my test project.

Is there one? Or do I need to build my own, or even is there an already made example of extending SciChart with TypeScript somewhere I’ve missed?

Thank you

Hi –

I could not find an example in the various examples your provide

I have several charts in different components

When a component is closed I want to ensure the chart is destroyed and there is not potential for memory leak

What is this best way of doing this?

Thanks

Hello,

I found an issue with very high memory usage by the application. after some tests I found the problem and moved it to a separate example(https://codepen.io/PodaRocheK/pen/PoVmzvP?editors=0011). Please check this code and observe the memory usage on this page. With prolonged use (after 10 minutes), it is clear that more and more memory is used. After hours, the memory used may already be more than several gigabytes. Tell me what the problem is, maybe I’m doing something wrong. Maybe I’m somehow storing old data incorrectly or adding it incorrectly.

This example is not a working example, it has been sped up in order to quickly identify the problem. In our example, an unnecessary data update will occur once every few seconds and after a night of inactivity, the entire page will die. Please tell me what the problem is.

Thank you!

Hi Folks,

Wanted to ensure I’m working in the right direction here. Requirement is to add inline series labels on the plot surface. It’s an awkward requirement at times, but it keeps coming up with because other providers do this sometimes.

I’ve been playing with the examples of using data labels ( https://github.com/ABTSoftware/SciChart.JS.Examples/blob/master/Examples/src/components/Examples/Charts2D/TooltipsAndHittest/UsingVerticalSliceModifier/index.tsx ).

This might work. It’s a little strange since I only need to show at most one label per series. So I use the data label provider I assume and have to manually space them along the index range.

The only alternative I’m aware of is the annotations api, which of course is quite robust and probably a little too fancy for this case.

Appreciate any thoughts on the approach here — thanks!

EDIT: Attached very contrived example. The idea is to supply a label to name the series inline (apparently a legend is not sufficient), but in a way that is reasonably useful visually (similar to the spacing capabilities in the data labels api). The text would be some piece of metadata that is derived from the series (or at least has a 1:1 relationship with the series).

When I’m using a BoxAnnotation, and it is selected, I can see that the borders are shown expanding past the chart area, on top of the axes.
Ideally they would have the same behaviour as the normal stroke, and keep constrained to the chart area.

Codepen showing the issue: https://codepen.io/jrfv/full/bGzqvoE

Am I missing some configuration to make this work?

Thanks!

Hi,

I am facing another issue with dataLabels in latest version of Scichart. I saw another question with similar is already posted and the fix is released.

Can you check this code.

I tried to reproduce the issue with the vue js example code, codesandbox. But the issues is behaving differently in example code, codesandbox, and my existing project.

codesandbox: https://codesandbox.io/s/scichart-error-6xc6jw?file=/src/index.ts
codesandbox:- Text in the bottom area are displayed and top area no labes are displayed.

I am attaching the vue js file also. Please check the file also, On the example no labels are displayed.

I am attaching the video of my project also, Here the labels are invisible sometimes, sometimes the labels are showing not properly. Video Link: https://drive.google.com/file/d/1vZ0lO5xdmN9VfFGXMaoTPfTgqRytrEAl/view?usp=sharing

I am using SciChartSurface.create() to create chart and it works well. However, I got the webGL memory issue randomly – WebGL memory issue. I am trying to apply a workaround to use SciChartSurface.createSinge() instead. The createSingle() function doesn’t work for me, the chart cannot be rendered.

const { sciChartSurface, wasmContext } = await SciChartSurface.createSinlge(`${chartId}-chart-root`, { theme: themeObj });

There is no error showing in the developer tool console. I have no idea what’s wrong.

Hello everyone,

I have 2 HorizontalLineAnnotations on the chart as price indicators. Sometimes i need to add to some label more data on the second line of the text. You can see example of correct annotation’s label. How can i add ‘\n’ or ‘
‘ to the text for such result?

Thank you a lot!

Hello everyone. A similar question has already been asked just below the forum, but there is no answer. I have dynamically added diagrams. However, I am interested in the possibility of adding buttons for closing and collapsing diagrams directly to the chart panel. I need the option to close any selected chart. How can this be implemented and written? Thank you.

Can I implement a feature in SciChart that allows me to pause and resume rendering activity on a SciChart renderable surface when a user clicks on the SciChart renderable surface?

I’m looking on https://demo.scichart.com/javascript-multi-pane-stock-charts-sync-technique
I have a q react application. Can I add/remove subcharts(indicator panes) dynamically?

I’m using an example of RealtimeTickingStockCharts

https://github.com/ABTSoftware/SciChart.JS.Examples/tree/master/Examples/src/components/Examples/Charts2D/CreateStockCharts/RealtimeTickingStockCharts

I’ve added a modifier

new YAxisDragModifier({
            dragMode: EDragMode.Scaling,
        }),

I see icon changed to arrows but scaling does not work. What should I check ?

Hi everyone,

I am using SciChart trial in Angular and I find it so powerful
Thanks for developing this
However, I am having some troubles using it with plotting realtime stock data

From having searched around I found that it is recommended to use CategoryAxis for stock charts to avoid gaps on days without data
However, how do I append/update the data with new data coming in
XYDataSeries.append takes a number for the x-value

In the code below, assume “addNewData” is called every second
How do I properly add the new data with the new DateTime and also format it however i would like

Thanks for your help

  sciChartSurface.xAxes.add(new CategoryAxis(wasmContext));
  sciChartSurface.yAxes.add(new NumericAxis(wasmContext,{
    axisAlignment: EAxisAlignment.Left,
  }));

  addNewData(){
    const x = new Number(new Date()).toString()
    if(this.sciChartSurface){
      const series = this.sciChartSurface.renderableSeries.get(0);
      const dataSeries = <XyDataSeries> series.dataSeries;
      const x = dataSeries.count();
      const y = Math.random()
      dataSeries.append(x, y)
      this.sciChartSurface.zoomExtents()
    }
  }

Hello,

Can you show this example(https://codepen.io/PodaRocheK/pen/yLGxGEL?editors=0011) and tell me, why metadata labels are not displayed in some cases? May be you can tell me how to do it correctly? A have similar chart with a lot of datapoints and can’t understand why labels show only in some time(20s or > 1m after start the chart)

Thank you!

Error from chart in div instrument_candle_chart_2
RuntimeError: call_indirect to a signature that does not match (evaluating ‘invoker(fn, thisWired, arg0Wired, arg1Wired, arg2Wired, arg3Wired, arg4Wired, arg5Wired, arg6Wired, arg7Wired, arg8Wired)

error here: OhlcSeriesDrawingProvider.prototype.draw:

this.nativeDrawingProvider.DrawPointsVec(nativeContext, xDrawValues, openValues, highValues, lowValues, closeValues, renderPassData.xCoordinateCalculator.nativeCalculator, renderPassData.yCoordinateCalculator.nativeCalculator, this.args);

Imagine I have a chart with a RolloverModifier, such that I see the point marker, and also a CursorModifier so I see the axis labels with the exact value I’m hovering.
This chart has the axis title hidden, and also the labels hidden, so I can really only see them trough the CursorModifier axis labels.
Since the axis title and labels are hidden, the axis labels spawn inside the chart, and the point marker from the RolloverModifier may be drawn on top of the labels.

I’d like to properly control drawing order here, so my axis labels get prioritised.
Is there a way to do so?

Codepen example: https://codepen.io/jrfv/full/VwqVBdo

Hello,

I need to customize the text for some points on a XyScatterRenderableSeries graph. The problem is that the dataLabelProvider available for XyScatterRenderableSeries is BaseDataLabelProvider, but it doesn’t have a metaDataSelector method and I can’t do it with it. Interestingly, using LineSeriesDataLabelProvider I was able to add text for the points I needed using metadata, but another problem arose. In this case, if there is only one point on the graph, the text will not be drawn.

Here is a small example of how text is drawn for different numbers of points. https://codepen.io/PodaRocheK/pen/jOXYGMJ?editors=0011

Can you advise me on how to display text near points more correctly in the case when I use XyScatterRenderableSeries and often this text should disappear or appear near some points. Thanks a lot!

Hi,
the Tooltip from the rolloverModifier shows for the Open-Values the Label “Open”.

I would like to be able to change that. There might be serveral reasons for that. Maybe the shown data are not “openValues” or the word “open” needs to be translated into another language.

I managed to edit the title of a FastCandlestickRenderableSeries by setting a title and get it into the variable like this:

rolloverTitle = newtitle;
renderableSeries0.rolloverModifierProps.tooltipTitle = rolloverTitle;

unfortunately i did not find a way to set the name/label for the open-,low-,close-, or high-values of this Series.

Can someone give ma a hint how to do this?

Hi,

EDataLabelSkipMode Customization is possible with some time range limit?
When i checked the documentation saw the options to skip the label for overlaping. Is it possible can add some index to skip the values. Eg: for Time chart One value is displayed in the chart at 10:30:00. So if i add some index value to skip the next 1 min data. So based on skip index next available value can ba displayed in chart. (10:31:00 or next available value). Can you implement this option to skip ?

Dear Andrew,

Thank you for the past answers. I have a new question. I have a heatmap with 2 line charts at its left aand top position. the top line chart plot the horizontal values where the mouse if hovering and left chart displays vertical values from the mouse position.

This is working great, but the issue is the heatmap is not always square and I am trying the aligh the line charts with the heatmap dimensions

two issues,

1. the heatmap X/Y dimension are not always same, in fact I have a function which listens to the changing heatmap zoom factor and makes sure the X/Y are always “square” as we want to show the heatmap with square pixels. (see video #2) https://youtu.be/wXStF-7bWsw

2. As I dynamically chage the size of the plot the… the proportion of actual chart area to axis lable changes thus varying the overlap. (see video #1) https://youtu.be/loAVpYSRJ38

Let me know if you need more information,

Best,

Pramod

Good afternoon. Please tell me how can I change the Z index of the annotations so that the box annotation can overlap the text. Now no matter how I try to do it, the text is always above the rectangles. Does the JS version have some layers with annotations that can be changed by they Z like in this question – https://www.scichart.com/questions/wpf/changing-an-annotations-z-index

Unfortunately, I did not find this functionality in the JS version.

In our app we have a feature by which user can add indicators. These indicators can consist of 2 or a maximum of 4 lines.

We don’t want to render svg tooltips(which setted up by the default) with data for each line, instead of that we get point data and pass it to our app inner service that can render indicator legend.

To prevent default tooltips from being displayed we set for each renderable series of an indicator the following values.

rolloverModifierProps.width = 0; rolloverModifierProps.height = 0;

But of course tooltips are still rendered in the DOM and this leads to performance issues when we have 3 or more indicators of this type.

My question is the following

How we can render only circles svg for rollover modifier and completely dont render svg for tooltips in the DOM?

This is what the indicators look like

Hi,

I am facing a issue with latest version of SciChart. Because of this type error not able to build the project. Can you check this error.

I’m trying to add an AxisMarkerAnnotations for some line series on my chart.

I was following these questions answered here:
https://www.scichart.com/questions/js/adding-axis-markers-to-fastlinerenderableseries
https://www.scichart.com/questions/js/price-indicators-on-yaxis

I managed to render the axis marker for my series. Now I’m trying to the set the Y value of the marker annotation as the value where the line intersects the Y Axis.
I want the marker value to be the last value of the series, only if the xAxis.visibleRange.max > series.XdataRange.max.

The two attached images show the desired feature.
One shows the marker annotation with the Y1 being the one where the line intersects the YAxis.
The other shows the marker annotation with the Y1 being the last value of the line, because it is visible.

I read some answers here on the forum about using the HitTest API to do this, but I couldn’t make it work on my JS app