When the size of the area is standard, which is in most cases, you can use a standard linear drain. They are available in many sizes: 24”, 28”, 32”, 36”, 48”, 58”. Drains don't need to run the full length of the wall, which allows you to use a standard length in most projects.
Can you put a linear drain in the middle of the shower?
Linear drains can be placed in the center of the shower, as seen in the bathroom below by Tego Bathroom Solutions, as long as they are parallel to the opening of the shower.