Using CursorModifier Crosshairs

Demonstrates how to create crosshairs on mouseover using SciChart.js, High Performance JavaScript Charts

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drawExample.ts

index.html

vanilla.ts

ExampleDataProvider.ts

theme.ts

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1import { appTheme } from "../../../theme";
2import { ExampleDataProvider } from "../../../ExampleData/ExampleDataProvider";
3import {
4    NumericAxis,
5    NumberRange,
6    SciChartSurface,
7    XyDataSeries,
8    ENumericFormat,
9    FastLineRenderableSeries,
10    EllipsePointMarker,
11    CursorModifier,
12    ZoomPanModifier,
13    ZoomExtentsModifier,
14    MouseWheelZoomModifier,
15    SeriesInfo,
16    CursorTooltipSvgAnnotation,
17} from "scichart";
18
19export const drawExample = async (rootElement: string | HTMLDivElement) => {
20    // Create a SciChartSurface with X,Y Axis
21    const { sciChartSurface, wasmContext } = await SciChartSurface.create(rootElement, {
22        theme: appTheme.SciChartJsTheme,
23    });
24
25    sciChartSurface.xAxes.add(
26        new NumericAxis(wasmContext, {
27            growBy: new NumberRange(0.05, 0.05),
28            labelFormat: ENumericFormat.Decimal,
29            labelPrecision: 4,
30        })
31    );
32
33    sciChartSurface.yAxes.add(
34        new NumericAxis(wasmContext, {
35            growBy: new NumberRange(0.1, 0.1),
36            labelFormat: ENumericFormat.Decimal,
37            labelPrecision: 4,
38        })
39    );
40
41    // Add some data
42    const data1 = ExampleDataProvider.getFourierSeriesZoomed(0.6, 0.13, 5.0, 5.15);
43    sciChartSurface.renderableSeries.add(
44        new FastLineRenderableSeries(wasmContext, {
45            dataSeries: new XyDataSeries(wasmContext, {
46                xValues: data1.xValues,
47                yValues: data1.yValues,
48                dataSeriesName: "First Line Series",
49            }),
50            strokeThickness: 3,
51            stroke: appTheme.VividSkyBlue,
52            pointMarker: new EllipsePointMarker(wasmContext, {
53                width: 7,
54                height: 7,
55                strokeThickness: 0,
56                fill: appTheme.VividSkyBlue,
57            }),
58        })
59    );
60
61    const data2 = ExampleDataProvider.getFourierSeriesZoomed(0.5, 0.12, 5.0, 5.15);
62    sciChartSurface.renderableSeries.add(
63        new FastLineRenderableSeries(wasmContext, {
64            dataSeries: new XyDataSeries(wasmContext, {
65                xValues: data2.xValues,
66                yValues: data2.yValues,
67                dataSeriesName: "Second Line Series",
68            }),
69            strokeThickness: 3,
70            stroke: appTheme.VividOrange,
71            pointMarker: new EllipsePointMarker(wasmContext, {
72                width: 7,
73                height: 7,
74                strokeThickness: 0,
75                fill: appTheme.VividOrange,
76            }),
77        })
78    );
79
80    const data3 = ExampleDataProvider.getFourierSeriesZoomed(0.4, 0.11, 5.0, 5.15);
81    sciChartSurface.renderableSeries.add(
82        new FastLineRenderableSeries(wasmContext, {
83            dataSeries: new XyDataSeries(wasmContext, {
84                xValues: data3.xValues,
85                yValues: data3.yValues,
86                dataSeriesName: "Third Line Series",
87            }),
88            strokeThickness: 3,
89            stroke: appTheme.MutedPink,
90            pointMarker: new EllipsePointMarker(wasmContext, {
91                width: 7,
92                height: 7,
93                strokeThickness: 0,
94                fill: appTheme.MutedPink,
95            }),
96        })
97    );
98
99    // Here is where we add cursor behaviour
100    //
101    sciChartSurface.chartModifiers.add(
102        // Add the CursorModifier (crosshairs) behaviour
103        new CursorModifier({
104            // Defines if crosshair is shown
105            crosshairStroke: appTheme.VividOrange,
106            crosshairStrokeThickness: 1,
107            showXLine: true,
108            showYLine: true,
109            // Shows the default tooltip
110            showTooltip: true,
111            tooltipContainerBackground: appTheme.VividOrange,
112            tooltipTextStroke: appTheme.ForegroundColor,
113            // Defines the axis label colours
114            axisLabelFill: appTheme.VividOrange,
115            axisLabelStroke: appTheme.ForegroundColor,
116            // Shows an additional legend in top left of the screen
117            tooltipLegendTemplate: getTooltipLegendTemplate,
118            // Use SVG to render the tooltip & axis labels of the CursorModifier
119            isSvgOnly: true,
120        }),
121        // Add further zooming and panning behaviours
122        new ZoomPanModifier({ enableZoom: true }),
123        new ZoomExtentsModifier(),
124        new MouseWheelZoomModifier()
125    );
126
127    return { sciChartSurface, wasmContext };
128};
129
130// Override the standard tooltip displayed by CursorModifier
131const getTooltipLegendTemplate = (seriesInfos: SeriesInfo[], svgAnnotation: CursorTooltipSvgAnnotation) => {
132    let outputSvgString = "";
133
134    // Foreach series there will be a seriesInfo supplied by SciChart. This contains info about the series under the house
135    seriesInfos.forEach((seriesInfo, index) => {
136        const lineHeight = 30;
137        const y = 20 + index * lineHeight;
138        // Use the series stroke for legend text colour
139        const textColor = seriesInfo.stroke;
140        // Use the seriesInfo formattedX/YValue for text on the
141        outputSvgString += `<text x="8" y="${y}" font-size="16" font-family="Verdana" fill="${textColor}">
142            ${seriesInfo.seriesName}: X=${seriesInfo.formattedXValue}, Y=${seriesInfo.formattedYValue}
143        </text>`;
144    });
145
146    return `<svg width="100%" height="100%">
147                ${outputSvgString}
148            </svg>`;
149};
150

Using Cursor Modifier Tooltips - JavaScript

Overview

This example demonstrates how to integrate SciChart.js into a JavaScript application to create high-performance, interactive charts. The implementation utilizes WebAssembly for efficient rendering as explained in the Performance Tips & Tricks documentation. Key features include the configuration of numeric axes, multiple fast line series, and advanced cursor behavior with custom tooltip support.

Technical Implementation

The chart is asynchronously initialized by creating a SciChartSurface along with X and Y axes configured through NumericAxis and NumberRange, ensuring precise label formatting (see The Numeric Axis for more details). Multiple FastLineRenderableSeries are added with corresponding XyDataSeries and EllipsePointMarker to effectively display data. The example adds several interactive chart modifiers including CursorModifier for crosshair behavior, ZoomPanModifier, ZoomExtentsModifier, and MouseWheelZoomModifier for intuitive zooming and panning. Custom tooltips are implemented by overriding the default behavior using an SVG template, as detailed in Customizing the CursorModifier Tooltip Container Appearance.

Features and Capabilities

This implementation provides dynamic updates with interactive zooming, panning, and detailed tooltips that display a legend for the underlying series. Advanced customization is achieved by dynamically generating SVG annotations for the tooltip, allowing a clear display of series names and formatted data values. Performance optimizations and resource management strategies using WebAssembly are employed to ensure smooth interactions.

Integration and Best Practices

The example follows best practices for asynchronous initialization and resource cleanup. A cleanup function is returned after the chart is created, and calling sciChartSurface.delete() ensures that resources are properly disposed of when the chart is no longer needed, thus preventing memory leaks. Developers can refer to the Getting Started with SciChart JS guide for further understanding of initializing and managing chart resources. Additionally, the axis configuration and tooltip customization patterns leveraged in this example align with the recommended approaches discussed in the SciChart documentation.

By using JavaScript, this example clearly illustrates how to build an interactive, high-performance chart with advanced visual customizations and robust user interaction capabilities.

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