program Project1;

{$APPTYPE CONSOLE}

uses
  StrUtils;

type
  TMyOSPlatform = (Windows, OSX, iOS, Android);

  TProperties = (Width, Height, MarginLeft);

const
  PropValues: array[TMyOSPlatform, TProperties] of Double = (
    (121, 22, 40), (128, 24, 40), (138, 24, 40), (140, 28, 40)
  );

  PropNames: array[TProperties] of string = ('Width', 'Height', 'MarginLeft');

const
  IDAktPlatform = TMyOSPlatform.Windows;

function ByPlatform(const Prop: string): Single;
begin
  Result := PropValues[IDAktPlatform, TProperties(IndexText(Prop, PropNames))];
end;

begin
end.