secure-sharing/SecureSharing/wwwroot/plugins/sparklines/sparkline.mjs

export default class Sparkline {
    constructor(element, options = {}) {
        this.element = element;
        this.options = {...Sparkline.options, ...options};

        {
            this.element.innerHTML = "<canvas></canvas>";
            this.canvas = this.element.firstChild;
            this.context = this.canvas.getContext("2d");
            this.ratio = window.devicePixelRatio || 1;

            if (this.options.tooltip) {
                this.canvas.style.position = "relative";
                this.canvas.addEventListener('mousemove', e => {
                    const x = e.offsetX || e.layerX || 0;
                    const delta = ((this.options.width - this.options.dotRadius * 2) / (this._points.length - 1));
                    const index = minmax(0, Math.round((x - this.options.dotRadius) / delta), this._points.length - 1);

                    this.canvas.title = this.options.tooltip(this._points[index], index, this._points);
                }, false);
            }
        }
    }

    get points() {
        return this._points;
    }

    set points(points) {
        this.draw(points);
    }

    static init(element, options) {
        return new Sparkline(element, options);
    }

    static draw(element, points, options) {
        const sparkline = new Sparkline(element, options);
        sparkline.draw(points);
        return sparkline;
    }

    draw(points = []) {
        this._points = points;

        this.canvas.width = this.options.width * this.ratio;
        this.canvas.style.width = `${this.options.width}px`;

        const pxHeight = this.options.height || this.element.offsetHeight;
        this.canvas.height = pxHeight * this.ratio;
        this.canvas.style.height = `${pxHeight}px`;

        const lineWidth = this.options.lineWidth * this.ratio;
        const offsetX = Math.max(this.options.dotRadius * this.ratio, lineWidth / 2);
        const offsetY = Math.max(this.options.dotRadius * this.ratio, lineWidth / 2);
        const width = this.canvas.width - offsetX * 2;
        const height = this.canvas.height - offsetY * 2;

        const minValue = Math.min.apply(Math, points);
        const maxValue = Math.max.apply(Math, points);
        const bottomValue = this.options.minValue != undefined ? this.options.minValue : Math.min(minValue, this.options.maxMinValue != undefined ? this.options.maxMinValue : minValue);
        const topValue = this.options.maxValue != undefined ? this.options.maxValue : Math.max(maxValue, this.options.minMaxValue != undefined ? this.options.minMaxValue : maxValue);
        let minX = offsetX;
        let maxX = offsetX;

        let x = offsetX;
        const y = index => (topValue === bottomValue)
            ? offsetY + height / 2
            : (offsetY + height) - ((points[index] - bottomValue) / (topValue - bottomValue)) * height;
        const delta = width / (points.length - 1);

        const line = (style, x, y) => {
            if (!style) return;

            this.context.save();
            this.context.strokeStyle = style.color || 'black';
            this.context.lineWidth = (style.width || 1) * this.ratio;
            this.context.globalAlpha = style.alpha || 1;
            this.context.beginPath();
            this.context.moveTo(style.direction != 'right' ? offsetX : x, y);
            this.context.lineTo(style.direction != 'left' ? width + offsetX : x, y);
            this.context.stroke();
            this.context.restore();
        }

        const dot = (color, lineStyle, x, y) => {
            this.context.beginPath();
            this.context.fillStyle = color;
            this.context.arc(x, y, this.options.dotRadius * this.ratio, 0, Math.PI * 2, false);
            this.context.fill();
            line(lineStyle, x, y);
        }

        this.context.save();

        this.context.strokeStyle = this.options.lineColor;
        this.context.fillStyle = this.options.lineColor;
        this.context.lineWidth = lineWidth;
        this.context.lineCap = 'round';
        this.context.lineJoin = 'round';

        if (this.options.fillBelow && points.length > 1) {
            this.context.save();
            this.context.beginPath();
            this.context.moveTo(x, y(0));
            for (let i = 1; i < points.length; i++) {
                x += delta;

                minX = points[i] == minValue ? x : minX;
                maxX = points[i] == maxValue ? x : maxX;

                this.context.lineTo(x, y(i));
            }
            this.context.lineTo(width + offsetX, height + offsetY + lineWidth / 2);
            this.context.lineTo(offsetX, height + offsetY + lineWidth / 2);
            this.context.fill();
            if (this.options.fillLighten > 0) {
                this.context.fillStyle = 'white';
                this.context.globalAlpha = this.options.fillLighten;
                this.context.fill();
                this.context.globalAlpha = 1;
            } else if (this.options.fillLighten < 0) {
                this.context.fillStyle = 'black';
                this.context.globalAlpha = -this.options.fillLighten;
                this.context.fill();
            }
            this.context.restore();
        }

        x = offsetX;
        this.context.beginPath();
        this.context.moveTo(x, y(0));
        for (let i = 1; i < points.length; i++) {
            x += delta;
            this.context.lineTo(x, y(i));
        }
        this.context.stroke();

        this.context.restore();

        line(this.options.bottomLine, 0, offsetY);
        line(this.options.topLine, 0, height + offsetY + lineWidth / 2);

        dot(this.options.startColor, this.options.startLine, offsetX + (points.length == 1 ? width / 2 : 0), y(0));
        dot(this.options.endColor, this.options.endLine, offsetX + (points.length == 1 ? width / 2 : width), y(points.length - 1));
        dot(this.options.minColor, this.options.minLine, minX + (points.length == 1 ? width / 2 : 0), y(points.indexOf(minValue)));
        dot(this.options.maxColor, this.options.maxLine, maxX + (points.length == 1 ? width / 2 : 0), y(points.indexOf(maxValue)));
    }
}

Sparkline.options = {
    width: 100,
    height: null,
    lineColor: "black",
    lineWidth: 1.5,
    startColor: "transparent",
    endColor: "black",
    maxColor: "transparent",
    minColor: "transparent",
    minValue: null,
    maxValue: null,
    minMaxValue: null,
    maxMinValue: null,
    dotRadius: 2.5,
    tooltip: null,
    fillBelow: true,
    fillLighten: 0.5,
    startLine: false,
    endLine: false,
    minLine: false,
    maxLine: false,
    bottomLine: false,
    topLine: false,
    averageLine: false
};

function minmax(a, b, c) {
    return Math.max(a, Math.min(b, c));
}