@jbrowse/plugin-wiggle/esm/drawLine.js

JBrowse 2 wiggle adapters, tracks, etc.

import { readConfObject } from '@jbrowse/core/configuration';
import { clamp, featureSpanPx } from '@jbrowse/core/util';
import { checkStopToken } from '@jbrowse/core/util/stopToken';
import { getScale } from './util';
const fudgeFactor = 0.3;
const clipHeight = 2;
export function drawLine(ctx, props) {
    const { features, regions, bpPerPx, scaleOpts, height: unadjustedHeight, ticks: { values }, displayCrossHatches, colorCallback, config, offset = 0, stopToken, } = props;
    const region = regions[0];
    const width = (region.end - region.start) / bpPerPx;
    const height = unadjustedHeight - offset * 2;
    const clipColor = readConfObject(config, 'clipColor');
    const scale = getScale({ ...scaleOpts, range: [0, height] });
    const domain = scale.domain();
    const niceMin = domain[0];
    const niceMax = domain[1];
    const toY = (n) => clamp(height - (scale(n) || 0), 0, height) + offset;
    let lastVal;
    let prevLeftPx = Number.NEGATIVE_INFINITY;
    const reducedFeatures = [];
    let start = performance.now();
    for (const feature of features.values()) {
        if (performance.now() - start > 400) {
            checkStopToken(stopToken);
            start = performance.now();
        }
        const [leftPx, rightPx] = featureSpanPx(feature, region, bpPerPx);
        if (Math.floor(leftPx) !== Math.floor(prevLeftPx) || rightPx - leftPx > 1) {
            reducedFeatures.push(feature);
            prevLeftPx = leftPx;
        }
        const score = feature.get('score');
        const lowClipping = score < niceMin;
        const highClipping = score > niceMax;
        const w = rightPx - leftPx + fudgeFactor;
        const c = colorCallback(feature, score);
        ctx.beginPath();
        ctx.strokeStyle = c;
        const startPos = lastVal !== undefined ? lastVal : score;
        if (!region.reversed) {
            ctx.moveTo(leftPx, toY(startPos));
            ctx.lineTo(leftPx, toY(score));
            ctx.lineTo(rightPx, toY(score));
        }
        else {
            ctx.moveTo(rightPx, toY(startPos));
            ctx.lineTo(rightPx, toY(score));
            ctx.lineTo(leftPx, toY(score));
        }
        ctx.stroke();
        lastVal = score;
        if (highClipping) {
            ctx.fillStyle = clipColor;
            ctx.fillRect(leftPx, offset, w, clipHeight);
        }
        else if (lowClipping && scaleOpts.scaleType !== 'log') {
            ctx.fillStyle = clipColor;
            ctx.fillRect(leftPx, height - clipHeight, w, height);
        }
    }
    if (displayCrossHatches) {
        ctx.lineWidth = 1;
        ctx.strokeStyle = 'rgba(200,200,200,0.5)';
        for (const tick of values) {
            ctx.beginPath();
            ctx.moveTo(0, Math.round(toY(tick)));
            ctx.lineTo(width, Math.round(toY(tick)));
            ctx.stroke();
        }
    }
    return {
        reducedFeatures,
    };
}