Using CursorModifier Crosshairs

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

Fullscreen

Edit

 Edit

Docs

drawExample.ts

index.tsx

ExampleDataProvider.ts

theme.ts

Copy to clipboard
Minimise
Fullscreen
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 in React

Overview

This example demonstrates how to integrate SciChart.js into a React application using the <SciChartReact/> component. It sets up a chart with X and Y numeric axes, renders multiple line series, and implements crosshair/cursor functionality along with customized tooltips. The example highlights how to leverage high-performance WebAssembly (WASM) rendering within a React environment.

Technical Implementation

The chart is created asynchronously through the drawExample function, which initializes a SciChartSurface with a chosen theme and adds NumericAxis configured with precise label formats. Three line series are added with distinct styling and point markers. The key feature is the use of the CursorModifier to provide crosshair behavior along with a custom tooltip legend, overridden via a dedicated function getTooltipLegendTemplate to display formatted series data. In addition, zoom and pan modifiers (ZoomPanModifier, ZoomExtentsModifier, and MouseWheelZoomModifier) are incorporated to enhance user interaction. This asynchronous pattern and separation of chart drawing logic from React components follows best practices for React integration and is detailed further in Creating a SciChart React Component from the Ground Up.

Features and Capabilities

The example emphasizes advanced tooltip customization through the CursorModifier, enabling dynamic display of series information as the user moves the mouse over the chart. In addition, it demonstrates advanced zooming and panning controls for detailed data inspection, which can be explored further in Advanced Zoom and Pan with SciChart.js. The use of a custom tooltip legend template allows for a clearly formatted, data-driven tooltip display.

Integration and Best Practices

Developers can see how the <SciChartReact/> component is used to seamlessly integrate high performance charts into a React application, maintaining separation of concerns by offloading chart rendering to a dedicated asynchronous function. The example emphasizes performance optimization through the use of a WebAssembly (WASM) context, as outlined in Deploying Wasm and Data Files with your app. Custom tooltips and legends are implemented by leveraging the CursorModifier, with complete API details available in the CursorModifier documentation.

SciChart Ltd, 16 Beaufort Court, Admirals Way, Docklands, London, E14 9XL.