I prefer them a little longer, 11" or right about where the bottom bisects the knees.
Not too slim, not too baggy.

/\  I live in poplin walk shorts just like those ....

just checked a pair of my J. Press poplins from the early '00s, they're 18 inches overall and have an inseam of 8.5 inches, they're great for me ... have had multiple pairs of these in navy, tan, and oyster over the years ....

and now a pair of J. Press madras shorts at 19.75 inches overall with an inseam of 9.25 inches, excellent pair in Dress Gordon ....

my Birdwells are 17 inches overall with a seven-inch inseam, that was the standard mid-sized length ....

currently wearing some old gray six-pocket sailing shorts, 18 inches overall with an inseam of 7.5 inches, these are probably the shortest I have but they're old-school sailing shorts, I have them in gray, navy, tan, and white, I use them as swim trunks as well:

    In 1965, Sportif began as a small business in southern California, headed by John G. Kirsch. In true entrepreneurial style, Kirsch sold tennis shorts from the back of the family's station                                                wagon, gradually building a reputation for quality and comfort. As this reputation grew, so did the market for high-quality outdoor clothing. Tennis shorts led to hiking, which led to  fishing and nautical apparel…and so the Sportif brand took shape. By 1968, Sportif had developed the first stretch fabric in the outdoor/boating industry, and its Original 6-Pocket Stretch Shorts were becoming a staple for outdoorsmen nationwide. In the early 70’s, John moved with his wife and children to the Sierra Nevadas, where his blossoming manufacturing business took root. For the next two decades, Sportif would continue to be an innovator in the outdoor clothing industry, as one of the first companies to utilize Gore-Tex and sun-protective fabrics. In the world of private label contracting, Sportif established itself as a premier manufacturer for companies like Eddie Bauer, L.L. Bean, and others.