Function createParticleArc

js/script.js:1485–1502

(start, arcLength, count, randomness, particleFactory)

// Helper used to semi-randomly spread particles over an arc
// Values are flexible - `start` and `arcLength` can be negative, and `randomness` is simply a multiplier for random addition.
function createParticleArc(start, arcLength, count, randomness, particleFactory) {
	const angleDelta = arcLength / count;
	// Sometimes there is an extra particle at the end, too close to the start. Subtracting half the angleDelta ensures that is skipped.
	// Would be nice to fix this a better way.
	const end = start + arcLength - angleDelta * 0.5;

	if (end > start) {
		// Optimization: `angle=angle+angleDelta` vs. angle+=angleDelta
		// V8 deoptimises with let compound assignment
		for (let angle = start; angle < end; angle = angle + angleDelta) {
			particleFactory(angle + Math.random() * angleDelta * randomness);
		}
	} else {
		for (let angle = start; angle > end; angle = angle + angleDelta) {
			particleFactory(angle + Math.random() * angleDelta * randomness);
		}
	}
}

//获取字体点阵信息
function getWordDots(word) {