Function calculateHeatColor

Lib/profiling/sampling/_heatmap_assets/heatmap.js:325–340

* Calculate heat color for given intensity (0-1) * Hot spans (>30%) get warm orange, cold spans get dimmed gray * @param {number} intensity - Value between 0 and 1 * @returns {string} rgba color string

(intensity)

 * @returns {string} rgba color string
 */
function calculateHeatColor(intensity) {
    // Hot threshold: only spans with >30% of max samples get color
    if (intensity > 0.3) {
        // Normalize intensity above threshold to 0-1
        const normalizedIntensity = (intensity - 0.3) / 0.7;
        // Warm orange-red with increasing opacity for hotter spans
        const alpha = 0.25 + normalizedIntensity * 0.35;  // 0.25 to 0.6
        const hotColor = getComputedStyle(document.documentElement).getPropertyValue('--span-hot-base').trim();
        return `rgba(${hotColor}, ${alpha})`;
    } else if (intensity > 0) {
        // Cold spans: very subtle gray, almost invisible
        const coldColor = getComputedStyle(document.documentElement).getPropertyValue('--span-cold-base').trim();
        return `rgba(${coldColor}, 0.1)`;
    }
    return 'transparent';
}

/**
 * Apply intensity-based heat colors to source spans