JavaScript Vector Field Plot

1import {
2    NumberRange,
3    SciChartSurface,
4    NumericAxis,
5    CentralAxesLayoutManager,
6    FastLineSegmentRenderableSeries,
7    IStrokePaletteProvider,
8    EStrokePaletteMode,
9    parseColorToUIntArgb,
10    IRenderableSeries,
11    TPaletteProviderDefinition,
12    EPaletteProviderType,
13    XyDataSeries,
14    ZoomPanModifier,
15    ZoomExtentsModifier,
16    MouseWheelZoomModifier,
17    FastTriangleRenderableSeries,
18    ETriangleSeriesDrawMode,
19    CursorModifier,
20    TCursorTooltipDataTemplate,
21    SeriesInfo,
22    XySeriesInfo,
23} from "scichart";
24
25import { appTheme } from "../../../theme";
26
27const lineStartColor = appTheme.VividBlue; //"red";
28const lineEndColor = appTheme.VividOrange; //"blue";
29
30class LineSegmentPaletteProvider implements IStrokePaletteProvider {
31    public readonly strokePaletteMode = EStrokePaletteMode.GRADIENT;
32    private readonly palettedStart = parseColorToUIntArgb(lineStartColor);
33    private readonly palettedEnd = parseColorToUIntArgb(lineEndColor);
34
35    public onAttached(parentSeries: IRenderableSeries): void {}
36
37    public onDetached(): void {}
38
39    public overrideStrokeArgb(xValue: number, yValue: number, index: number): number {
40        return index % 2 === 0 ? this.palettedStart : this.palettedEnd;
41    }
42
43    public toJSON(): TPaletteProviderDefinition {
44        return { type: EPaletteProviderType.Custom, customType: "MyPaletteProvider" };
45    }
46}
47
48// Tooltip Data Template
49const tooltipDataTemplate: TCursorTooltipDataTemplate = (seriesInfos: SeriesInfo[]) => {
50    const valuesWithLabels: string[] = [];
51    seriesInfos.forEach((si) => {
52        const xySI = si as XySeriesInfo;
53        if (xySI.isWithinDataBounds) {
54            if (!isNaN(xySI.yValue) && xySI.isHit) {
55                valuesWithLabels.push(
56                    `start (${xySI.xValue},${xySI.yValue}) end (${xySI.point2xValue},${xySI.point2yValue})`
57                );
58            }
59        }
60    });
61    return valuesWithLabels;
62};
63
64function addArrowheads(xValues: number[], yValues: number[], arrowLength = 0.2, arrowAngle = Math.PI / 12) {
65    function distance(x1: number, y1: number, x2: number, y2: number) {
66        return Math.hypot(x2 - x1, y2 - y1);
67    }
68
69    const arrows = [];
70    for (let i = 0; i < xValues.length; i += 2) {
71        // Line start and end
72        const x1 = xValues[i];
73        const y1 = yValues[i];
74        const x2 = xValues[i + 1];
75        const y2 = yValues[i + 1];
76
77        // Direction of the line
78        const dx = x2 - x1;
79        const dy = y2 - y1;
80        const lineAngle = Math.atan2(dy, dx);
81
82        // Arrowhead points
83        const angle1 = lineAngle + Math.PI - arrowAngle;
84        const angle2 = lineAngle + Math.PI + arrowAngle;
85
86        const arrowPoint1 = [x2 + arrowLength * Math.cos(angle1), y2 + arrowLength * Math.sin(angle1)];
87        const arrowPoint2 = [x2 + arrowLength * Math.cos(angle2), y2 + arrowLength * Math.sin(angle2)];
88
89        // Arrowhead: [tip, base1, base2]
90        arrows.push([
91            [x2, y2], // Tip of the arrow
92            arrowPoint1, // First base point
93            arrowPoint2, // Second base point
94        ]);
95    }
96    return arrows;
97}
98
99export const drawExample = async (rootElement: string | HTMLDivElement) => {
100    // Create a SciChartSurface
101    const { sciChartSurface, wasmContext } = await SciChartSurface.create(rootElement, {
102        theme: appTheme.SciChartJsTheme,
103    });
104
105    // configure central axes
106    const layoutManager = new CentralAxesLayoutManager();
107
108    sciChartSurface.layoutManager = layoutManager;
109
110    const xMin = -15;
111    const xMax = 15;
112    const yMin = -10;
113    const yMax = 10;
114
115    const growBy = new NumberRange(0.1, 0.1);
116
117    const xAxis = new NumericAxis(wasmContext, {
118        axisBorder: { color: "white", borderBottom: 1 },
119        drawMajorBands: false,
120        drawMajorGridLines: false,
121        drawMinorGridLines: false,
122        growBy,
123    });
124    sciChartSurface.xAxes.add(xAxis);
125
126    const yAxis = new NumericAxis(wasmContext, {
127        axisBorder: { color: "white", borderRight: 1 },
128        drawMajorBands: false,
129        drawMajorGridLines: false,
130        drawMinorGridLines: false,
131        growBy,
132    });
133    sciChartSurface.yAxes.add(yAxis);
134
135    const multiplier = 0.01;
136
137    const linesXValues: number[] = [];
138    const linesYValues: number[] = [];
139
140    for (let x = xMin; x <= xMax; x++) {
141        for (let y = yMin; y <= yMax; y++) {
142            // start point
143            // dataSeries.append(x, y);
144            linesXValues.push(x);
145            linesYValues.push(y);
146            // end point
147            const xEnd = x + (x * x - y * y - 4) * multiplier;
148            const yEnd = y + 2 * x * y * multiplier;
149
150            linesXValues.push(xEnd);
151            linesYValues.push(yEnd);
152        }
153    }
154
155    const lineSegmentSeries = new FastLineSegmentRenderableSeries(wasmContext, {
156        dataSeries: new XyDataSeries(wasmContext, {
157            xValues: linesXValues,
158            yValues: linesYValues,
159        }),
160        strokeThickness: 2,
161        paletteProvider: new LineSegmentPaletteProvider(),
162    });
163
164    const arrowheads = addArrowheads(linesXValues, linesYValues);
165
166    //console.log(arrowheads.flat());
167
168    const arrowheadsXvalues = arrowheads.flat().map((d) => d[0]);
169    const arrowheadsYvalues = arrowheads.flat().map((d) => d[1]);
170
171    const polygonSeries = new FastTriangleRenderableSeries(wasmContext, {
172        dataSeries: new XyDataSeries(wasmContext, {
173            xValues: arrowheadsXvalues,
174            yValues: arrowheadsYvalues,
175        }),
176        isDigitalLine: false,
177        opacity: 1,
178        fill: lineEndColor,
179        drawMode: ETriangleSeriesDrawMode.List, // Polygon / List / Strip
180    });
181
182    sciChartSurface.renderableSeries.add(lineSegmentSeries);
183
184    sciChartSurface.renderableSeries.add(polygonSeries);
185
186    sciChartSurface.chartModifiers.add(new ZoomPanModifier());
187    sciChartSurface.chartModifiers.add(new ZoomExtentsModifier());
188    sciChartSurface.chartModifiers.add(new MouseWheelZoomModifier());
189    sciChartSurface.chartModifiers.add(new CursorModifier({ showTooltip: true, tooltipDataTemplate }));
190
191    return { sciChartSurface, wasmContext };
192};
193