Samsung is rumored to be working on the Galaxy P30 and P30+ phones, which will be its first with an in-display fingerprint reader. A few more details have emerged about those two, which will likely go official before the end of the year (and thus before the new Galaxy S flagships).
The Samsung Galaxy P30 (SM-G6200) will come with 64GB or 128GB storage and in four paint jobs: Blue, Red, Pink and Black. They will be gradients rather than solid colors, similar to the recent incarnations of the Galaxy A9 Star.
Note that these will reportedly use LCD displays rather than OLEDs, but the fingerprint reader is an optical unit (current optical readers work only on OLED screens). Insider info claims that Samsung will use ultrasonic readers for the new Galaxy S flagship and the company is well known for its Super AMOLED displays, so going with LCD is a strange move.vivo's in display optical fingerprint reader solution
The Galaxy P-series will most likely launch in China first, where a highly competitive field of phones with in display FP readers has taken shape. Chances are that we'll never see the P-series launch in the West, where penetration of in-display readers is fairly low (at least until the new Galaxy S phones launch in a few months).