JavaScript Chart with BaseValue Axes

1import {
2    AnnotationDragDeltaEventArgs,
3    BaseValueAxis,
4    CoordinateCalculatorBase,
5    CursorModifier,
6    ELabelPlacement,
7    EllipsePointMarker,
8    EXyDirection,
9    FastLineRenderableSeries,
10    MouseWheelZoomModifier,
11    NumberRange,
12    NumericAxis,
13    SciChartSurface,
14    VerticalLineAnnotation,
15    XDataSeries,
16    XyDataSeries,
17    ZoomExtentsModifier,
18    ZoomPanModifier,
19} from "scichart";
20import { ExampleDataProvider } from "../../../ExampleData/ExampleDataProvider";
21import { appTheme } from "../../../theme";
22
23/**
24 * Generate baseValues for a non-linear scale based on a power law
25 * @param visibleRange The visible range to generate values for
26 * @param base The base for the power law (e.g., 10 for powers of 10)
27 * @returns An array of values based on the power law, including zero if in range
28 */
29const generatePowerLawBaseValues = (
30    visibleRange: NumberRange,
31    base: number = 10,
32    minimumPower: number = 1
33): number[] => {
34    const baseValues: number[] = [];
35
36    // Generate negative powers
37    if (visibleRange.min < 0) {
38        const lowPower = Math.ceil(Math.log(Math.abs(visibleRange.min)) / Math.log(base));
39        const max =
40            visibleRange.max >= 0 ? minimumPower : Math.floor(Math.log(Math.abs(visibleRange.max)) / Math.log(base));
41        for (let power = lowPower; power >= minimumPower; power--) {
42            const value = -Math.pow(base, power);
43            baseValues.push(value);
44        }
45    }
46
47    // Add zero if it's within the range
48    if (visibleRange.min <= 0 && visibleRange.max >= 0) {
49        baseValues.push(0);
50    }
51
52    // Generate positive powers
53    if (visibleRange.max > 0) {
54        const highPower = Math.ceil(Math.log(Math.abs(visibleRange.max)) / Math.log(base));
55        const min =
56            visibleRange.min <= 0 ? minimumPower : Math.floor(Math.log(Math.abs(visibleRange.min)) / Math.log(base));
57        for (let power = minimumPower; power <= highPower; power++) {
58            const value = Math.pow(base, power);
59            baseValues.push(value);
60        }
61    }
62    return baseValues;
63};
64
65export const drawExample = async (rootElement: string | HTMLDivElement) => {
66    const { sciChartSurface, wasmContext } = await SciChartSurface.create(rootElement, {
67        theme: appTheme.SciChartJsTheme,
68    });
69
70    const xAxis = new BaseValueAxis(wasmContext, {
71        id: "BaseValueAxis",
72        visibleRange: new NumberRange(-0.1, 10.1),
73        flippedCoordinates: false,
74        labelPrecision: 3,
75        cursorLabelPrecision: 2,
76        baseValues: [0, 1, 2, 3, 4, 4.5, 4.6, 4.7, 4.8, 4.9, 5, 5.1, 5.2, 5.3, 5.4, 5.5, 6, 7, 8, 9, 10],
77        // autoTicks: true,
78        // majorDelta: 10,
79        // minorDelta: 2,
80        // labelProvider: new NumericLabelProvider()
81    });
82    sciChartSurface.xAxes.add(xAxis);
83    const baseXValues = xAxis.getBaseValues() as XDataSeries;
84
85    // Generate baseYValues using power law with base 10
86    const initialVisibleRange = new NumberRange(-500, 500);
87    const powerLawBase = 10;
88    const baseYValueSeries = new XDataSeries(wasmContext, {
89        xValues: generatePowerLawBaseValues(initialVisibleRange, powerLawBase),
90    });
91
92    const yAxis = new BaseValueAxis(wasmContext, {
93        visibleRange: initialVisibleRange,
94        minorsPerMajor: 9,
95        baseValues: baseYValueSeries,
96        autoTicks: false,
97    });
98    yAxis.visibleRangeChanged.subscribe((data) => {
99        baseYValueSeries.clear();
100        baseYValueSeries.appendRange(
101            generatePowerLawBaseValues(yAxis.visibleRange.union(initialVisibleRange), powerLawBase)
102        );
103    });
104
105    yAxis.tickProvider.getMajorTicks = (
106        minorDelta: number,
107        majorDelta: number,
108        visibleRange: NumberRange,
109        coordCalc?: CoordinateCalculatorBase
110    ) => {
111        const ticks = generatePowerLawBaseValues(visibleRange, powerLawBase);
112        return ticks;
113    };
114
115    yAxis.tickProvider.getMinorTicks = (
116        minorDelta: number,
117        majorDelta: number,
118        visibleRange: NumberRange,
119        coordCalc?: CoordinateCalculatorBase
120    ) => {
121        const majors = generatePowerLawBaseValues(visibleRange, powerLawBase);
122        const minors: number[] = [];
123        for (let i = 0; i < majors.length - 1; i++) {
124            const cur = majors[i];
125            const next = majors[i + 1];
126            const mpm = yAxis.minorsPerMajor + (next === 0 || cur === 0 ? 1 : 0);
127            const step = (next - cur) / mpm;
128            for (let j = 1; j < mpm; j++) {
129                minors.push(cur + step * j);
130            }
131        }
132        return minors;
133    };
134
135    sciChartSurface.yAxes.add(yAxis);
136
137    const lineSeries = new FastLineRenderableSeries(wasmContext, {
138        stroke: "white",
139        pointMarker: new EllipsePointMarker(wasmContext, {
140            width: 9,
141            height: 9,
142            strokeThickness: 0,
143            fill: "steelblue",
144            stroke: "LightSteelBlue",
145        }),
146    });
147
148    lineSeries.rolloverModifierProps.tooltipTextColor = "black";
149
150    sciChartSurface.renderableSeries.add(lineSeries);
151
152    const { xValues, yValues } = ExampleDataProvider.getNoisySinewave(1000, 10, 10, 150, 20);
153    lineSeries.dataSeries = new XyDataSeries(wasmContext, { xValues: xValues, yValues });
154
155    // We use a hidden numeric axis synced to the BaseValue x axis to position the vertical line
156    const linearXAxis = new NumericAxis(wasmContext, {
157        isVisible: false,
158        visibleRange: xAxis.visibleRange,
159    });
160    sciChartSurface.xAxes.add(linearXAxis);
161    xAxis.visibleRangeChanged.subscribe((data) => (linearXAxis.visibleRange = data.visibleRange));
162
163    const magnifierAnnotation = new VerticalLineAnnotation({
164        xAxisId: linearXAxis.id,
165        x1: 5,
166        stroke: appTheme.MutedOrange,
167        strokeThickness: 3,
168        labelValue: "Drag Me!",
169        showLabel: true,
170        labelPlacement: ELabelPlacement.Top,
171        isEditable: true,
172        onDrag: (args: AnnotationDragDeltaEventArgs) => {
173            // Update the BaseValues adding more points around the annotation x coordinate, effectively zooming in that area and compressing elsewhere
174            const newBaseValues: number[] = [];
175            for (let x = 0; x <= 10; x++) {
176                if (x < args.sender.x1 - 0.5 || x > args.sender.x1 + 0.5) {
177                    newBaseValues.push(x);
178                } else {
179                    for (let d = -0.5; d <= 0.5; d += 0.1) {
180                        newBaseValues.push(args.sender.x1 + d);
181                    }
182                }
183            }
184            baseXValues.clear();
185            baseXValues.appendRange(newBaseValues);
186        },
187    });
188
189    sciChartSurface.annotations.add(magnifierAnnotation);
190
191    sciChartSurface.chartModifiers.add(
192        new ZoomPanModifier({ xyDirection: EXyDirection.XyDirection, includedXAxisIds: [xAxis.id] })
193    );
194    sciChartSurface.chartModifiers.add(new ZoomExtentsModifier({ includedXAxisIds: [xAxis.id] }));
195    sciChartSurface.chartModifiers.add(new MouseWheelZoomModifier({ includedXAxisIds: [xAxis.id] }));
196    sciChartSurface.chartModifiers.add(new CursorModifier({ showAxisLabels: true }));
197
198    return { sciChartSurface, wasmContext };
199};
200