@Kent1Cooper wrote:
....
A no-routine-required suggestion, if the spacings should be the same in both directions : Draw a User-defined both-directions Hatch pattern .... place sprinklers at the intersections of the Lines resulting from Exploding the Hatch pattern.
Here's an example in a shape similar to the one marked, whether actually accomplished by way of a Hatch pattern or by calculation somehow:

Of course, the size of the spacing grid relative to the room is arbitrary, but the same issues could occur at any relationship between room size and sprinkler spacing.
I put the Hatch pattern origin at the middle of the shape's bounding box, and it goes from there. There are some heads ridiculously close to walls, and some areas around the perimeter that are probably not covered adequately. The grid positioning could be moved around in various ways to try to improve on those faults, but "fixing" one issue is likely to cause others elsewhere.
I can imagine that the best you'll be able to do is a routine that gives a first-pass layout similar to this, and you will need to make adjustments.
I tried rotating the pattern to be parallel to the longest edge, thinking that might give a more efficient layout. Given the same size grid, still generated from the middle of the bounding box:

Obviously, the middle of the bounding box is not always going to be the best place to put the Hatch pattern origin. A routine could perhaps be made to put the first row of heads a half-spacing off the longest edge, and go from there, but the positioning in the other direction would be a challenge, and the same kinds of "issues" will no doubt occur along other edges.
Kent Cooper, AIA