thi-ng/umbrella

import type { NumericArray } from "@thi.ng/api";
import { ensureArray } from "@thi.ng/arrays/ensure-array";
import { peek } from "@thi.ng/arrays/peek";
import { fitClamped } from "@thi.ng/math/fit";
import { minMax } from "@thi.ng/math/interval";
import { max as $max } from "@thi.ng/transducers/max";
import { min as $min } from "@thi.ng/transducers/min";
import type { BlendFn } from "./api.js";
import { barChartVLines } from "./bars.js";
import { Canvas } from "./canvas.js";
import { formatCanvas } from "./format.js";
import { blendBarsVAdd, blitBarsV } from "./image.js";
import { textLines } from "./text.js";

export interface PlotBarsVOpts {
    min: number;
    max: number;
    blend?: BlendFn;
}

export interface PlotSpec {
    data: NumericArray;
    color: number;
}

export const plotBarChartV = (
    canv: Canvas,
    opts: PlotBarsVOpts,
    ...plots: PlotSpec[]
) => {
    const channel = canv.empty();
    const blend = opts.blend || blendBarsVAdd;
    for (let plot of plots) {
        channel.clear();
        textLines(
            channel,
            0,
            0,
            barChartVLines(channel.height, plot.data, opts.min, opts.max),
            plot.color
        );
        blitBarsV(canv, channel, 0, 0, blend);
    }
    return canv;
};

export const plotLineChart = (
    canvas: Canvas,
    x: number,
    y: number,
    height: number,
    vals: Iterable<number>,
    min?: number,
    max?: number,
    format = canvas.format
) => {
    const $vals = ensureArray(vals);
    min = min !== undefined ? min : $min($vals);
    max = max !== undefined ? max : $max($vals);
    height--;
    format <<= 16;
    const { x1, x2 } = peek(canvas.clipRects);
    for (let i = 0, n = $vals.length - 1; i < n; i++) {
        const xx = x + i;
        if (xx < x1) continue;
        if (xx > x2) break;
        const ya = Math.round(fitClamped($vals[i], min, max, height, 0)) + y;
        const yb =
            Math.round(fitClamped($vals[i + 1], min, max, height, 0)) + y;
        if (ya === yb) {
            canvas.setAt(xx, ya, 0x2500 | format); // ─
        } else {
            // vline to new Y
            let [y1, y2] = minMax(ya, yb);
            while (++y1 < y2) canvas.setAt(xx, y1, 0x2502 | format); // │
            // end points
            canvas.setAt(xx, ya, (ya < yb ? 0x256e : 0x256f) | format); // ╮ ╯
            canvas.setAt(xx, yb, (ya < yb ? 0x2570 : 0x256d) | format); // ╰ ╭
        }
    }
};

export const lineChartStr = (
    height: number,
    vals: Iterable<number>,
    min?: number,
    max?: number
) => {
    const $vals = ensureArray(vals);
    const surf = new Canvas($vals.length, height);
    plotLineChart(surf, 0, 0, height, $vals, min, max);
    return formatCanvas(surf);
};