src/vs/editor/contrib/colorPicker/browser/colorPickerWidget.ts/SaturationBox/onDidChangePosition
class SaturationBox:	private onDidChangePosition(left: number, top: number): void {
		const s = Math.max(0, Math.min(1, left / this.width));
		const v = Math.max(0, Math.min(1, 1 - (top / this.height)));

		this.paintSelection(s, v);
		this._onDidChange.fire({ s, v });
	}