The word "easy" here does not mean "simple", nor does it mean "casual", but it means quickly, "in a blink of an eye" or "inadvertently".
This kind of usage is very common in poetry, such as Lu You's "Yanxi Lou" poem: "Thousands of miles have followed the rules and become long-term guests, and the autumn wind is easy to come back every year." Sima Guang's "The mind is slowly chasing away Hong" , Don’t come easy to the four autumn winds.” That is to say, the year has passed quickly, and in a blink of an eye, it is the season of autumn wind again.
As for the "half window" and "horizontal branches", they are used to build the aesthetic beauty of the poem. In the window, the horizontal branches are half-hidden, like a painting.
It is easy to get a strong fragrance close to the painting screen, and the branches cover half of the window. These two poems are related. The translation is - inadvertently, the branches cover half of the window, and inadvertently the screen is filled with Strong aroma.
Easily, in a blink of an eye, inadvertently, describe the author's psychological state of time. In fact, the speed of time remains unchanged, but the author suddenly realized that time had passed... A hundred-year-old life It’s easy to grow old, it’s worth having a glass of wine - I also wrote a sentence to express the feeling of "easy".