In The Lady of Shallot what sight in the mirror causes the Lady to say that she is half sick of shadows?

In "The Lady of Shalott," the sight that makes her feel "half sick of shadows" is the reflection of Sir Lancelot, who is riding by her tower. She has been observing the world only through a mirror, which distorts and limits her experiences. His vibrant presence captivates her, stirring a longing for real connection and life beyond her isolated existence. This moment marks her desire to break free from her confinement and engage with the world directly.