How does the setting reinforce Mrs. Mallard's feelings after she learns about the death of her husband?

In this very short story by Kate Chopin, there are several examples of how the setting reinforces the way Mrs. Mallard feels after she learns about her husband's death. At the opening of the story, Mrs. Mallard is told by her sister and friend that her husband has been killed in a train accident. After learning this news, Mrs. Mallard retreats to an empty room. 

Almost immediately, we begin to see signs of the setting reinforcing and reflecting her mood through specific imagery. A "comfortable, roomy" armchair accepts her shocked body. She looks out the window and sees that the trees are "all aquiver with new spring life," the air smells like rain, and the birds are singing. These details about spring are important because spring is the season of renewal; Mrs. Mallard's life is changing, like winter changes to spring, because she feels free and new after her husband's death. 

As she contemplates her changed situation, she regularly returns to view the "patches of blue sky" she sees through the window, suggesting she feels peaceful and hopeful since blue is the color of peace. Then Mrs. Mallard feels that something is approaching her—something she cannot name—"creeping out of the sky, reaching toward her through the sounds, the scents, the color that filled the air." Her apprehension about her future—a future without the constraints of her present life—is reflected in the swirl of sounds, smells, and colors outside her window.

Finally, that open window represents all of the wonderful possibilities of a future without her husband. Near the end of the story, just before the surprising arrival of her husband, the narrator tells us that Mrs. Mallard is "drinking in a very elixir of life" through this window. An "elixir" is a magical potion, so in this sense the window is offering her a delicious, welcome change in the same way her new life as a widow is welcome and full of delicious possibilities. 

In this story, then, the room to which she retreats and the world she sees outside her window reveal Mrs. Mallard's inner thoughts at the same time they reinforce them through imagery.