format()

in _docs/assets/js/railroad.js [796:891]

• 90 lines of code
• 11 McCabe index (conditional complexity)

	format(x,y,width) {
		// Hook up the two sides if this is narrower than its stated width.
		var gaps = determineGaps(width, this.width);
		new Path(x,y).h(gaps[0]).addTo(this);
		new Path(x+gaps[0]+this.width,y+this.height).h(gaps[1]).addTo(this);
		x += gaps[0];

		const first = this.items[0];
		const last = this.items[this.items.length-1];
		const allButFirst = this.items.slice(1);
		const allButLast = this.items.slice(0, -1);

		// upper track
		var upperSpan = (sum(allButLast, x=>x.width+(x.needsSpace?20:0))
			+ (this.items.length - 2) * Options.AR*2
			- Options.AR
		);
		new Path(x,y)
			.arc('se')
			.v(-(this._upperTrack - Options.AR*2))
			.arc('wn')
			.h(upperSpan)
			.addTo(this);

		// lower track
		var lowerSpan = (sum(allButFirst, x=>x.width+(x.needsSpace?20:0))
			+ (this.items.length - 2) * Options.AR*2
			+ (last.height > 0 ? Options.AR : 0)
			- Options.AR
		);
		var lowerStart = x + Options.AR + first.width+(first.needsSpace?20:0) + Options.AR*2;
		new Path(lowerStart, y+this._lowerTrack)
			.h(lowerSpan)
			.arc('se')
			.v(-(this._lowerTrack - Options.AR*2))
			.arc('wn')
			.addTo(this);

		// Items
		for(const [i, item] of enumerate(this.items)) {
			// input track
			if(i === 0) {
				new Path(x,y)
					.h(Options.AR)
					.addTo(this);
				x += Options.AR;
			} else {
				new Path(x, y - this._upperTrack)
					.arc('ne')
					.v(this._upperTrack - Options.AR*2)
					.arc('ws')
					.addTo(this);
				x += Options.AR*2;
			}

			// item
			var itemWidth = item.width + (item.needsSpace?20:0);
			item.format(x, y, itemWidth).addTo(this);
			x += itemWidth;

			// output track
			if(i === this.items.length-1) {
				if(item.height === 0) {
					new Path(x,y)
						.h(Options.AR)
						.addTo(this);
				} else {
					new Path(x,y+item.height)
					.arc('se')
					.addTo(this);
				}
			} else if(i === 0 && item.height > this._lowerTrack) {
				// Needs to arc up to meet the lower track, not down.
				if(item.height - this._lowerTrack >= Options.AR*2) {
					new Path(x, y+item.height)
						.arc('se')
						.v(this._lowerTrack - item.height + Options.AR*2)
						.arc('wn')
						.addTo(this);
				} else {
					// Not enough space to fit two arcs
					// so just bail and draw a straight line for now.
					new Path(x, y+item.height)
						.l(Options.AR*2, this._lowerTrack - item.height)
						.addTo(this);
				}
			} else {
				new Path(x, y+item.height)
					.arc('ne')
					.v(this._lowerTrack - item.height - Options.AR*2)
					.arc('ws')
					.addTo(this);
			}
		}
		return this;
	}