Generate srcset images for a variety of resolutions from OCaml
anil.recoil.org
1(** Image entry management for responsive image generation.
2
3 This module provides types and functions for managing image entries
4 that contain metadata about responsive images including their dimensions
5 and size variants. *)
6
7(** {1 Types} *)
8
9(** String map for storing image variants keyed by filename. *)
10module MS : Map.S with type key = string
11
12(** An image entry representing a source image and its generated variants.
13
14 Each entry tracks:
15 - The output filename ([name])
16 - A URL-safe identifier ([slug])
17 - The original source path ([origin])
18 - Image dimensions as [(width, height)]
19 - A map of variant filenames to their dimensions *)
20type t = {
21 name : string;
22 slug : string;
23 origin : string;
24 dims : int * int;
25 variants : (int * int) MS.t;
26}
27
28(** {1 Constructors} *)
29
30val v : string -> string -> string -> (int * int) MS.t -> int * int -> t
31(** [v name slug origin variants dims] creates a new image entry.
32
33 @param name The output filename (e.g., ["photo.webp"])
34 @param slug A URL-safe identifier derived from the filename
35 @param origin The original source file path
36 @param variants Map of variant filenames to their [(width, height)] dimensions
37 @param dims The base image dimensions as [(width, height)] *)
38
39(** {1 Accessors} *)
40
41val name : t -> string
42(** [name entry] returns the output filename. *)
43
44val slug : t -> string
45(** [slug entry] returns the URL-safe identifier. *)
46
47val origin : t -> string
48(** [origin entry] returns the original source file path. *)
49
50val dims : t -> int * int
51(** [dims entry] returns the base image dimensions as [(width, height)]. *)
52
53val variants : t -> (int * int) MS.t
54(** [variants entry] returns the map of variant filenames to dimensions. *)
55
56(** {1 JSON Serialization} *)
57
58val json_t : t Jsont.t
59(** JSON codec for a single image entry. *)
60
61val list : t list Jsont.t
62(** JSON codec for a list of image entries. *)
63
64val list_to_json : t list -> (string, string) result
65(** [list_to_json entries] serializes a list of entries to a JSON string.
66
67 Returns [Ok json_string] on success, or [Error message] if encoding fails. *)
68
69val list_of_json : string -> (t list, string) result
70(** [list_of_json json_string] parses a JSON string into a list of entries.
71
72 Returns [Ok entries] on success, or [Error message] if parsing fails. *)