F# script to compute image aspect ratio

aspect_ration.fs

open System

let resolutions = 
    [
        ((1,1), (1080 , 1080));
        ((3,2), (1080 , 720));
        ((4,3), (1024 , 768));
        ((16,9), (1920 , 1080));
        ((16,10), (1920 , 1200));
    ]
let resolutions_with_ratio = 
    resolutions
    |> List.map (fun ((x :int, y:int),(h,v)) -> (float x/ float y, ((x,y),(h,v))))


let findClosestRatio ratio =
    resolutions_with_ratio
        |> List.map 
            (fun (orig_ratio, data) -> 
                (abs (ratio - orig_ratio), orig_ratio, data))
        |> List.minBy (fun (distance, aspect, data) -> distance)

[<EntryPoint>]
let main(args) =    
    match args with
    | [|_; resolution|] ->
        printf $"Requested resolution is {resolution}\n"
        match resolution.Split [|'x'|] with
        | [|x;y|] ->
            printf $"Comparing resolution {x} x {y} to various aspect ratios...\n"
            match (System.Int32.TryParse x, System.Int32.TryParse y) with
            | ((true, xInt), (true, yInt)) ->
                let max, min = Math.Max(xInt, yInt), Math.Min(xInt, yInt)
                let ratio = float max / float min
                printf $"Resolution {xInt} * {yInt} has normalized ratio %0.3f{ratio}\n"
                
                let distance, closest_ratio, ((x_r, y_r),(h,v)) = 
                    findClosestRatio ratio
                
                printf $"Closest ratio is %0.3f{closest_ratio} with distance %0.1f{distance/closest_ratio * 100.}%% \n"
                printf $"Aspect is {x_r}:{y_r} --> Closest monitor resolution is {h}x{v}\n"
            | _ ->  failwith "The 'resolution' parameter should use the format 1234x5678"
        | _ -> failwith "The 'resolution' parameter should use the format 1234x5678"
    | _ -> failwith "Usage aspect_ratio <resolution>"

    0