Implement listing of page info in JSON

cpdfcommand.ml

@@ -3489,7 +3489,7 @@ let go () =
       | (_, pagespec, _, _, _, _)::_, _ ->
           let pdf = get_single_pdf args.op true in
             let range = parse_pagespec_allow_empty pdf pagespec in
-              Cpdfpage.output_page_info pdf range
+              Cpdfpage.output_page_info ~json:args.format_json pdf range
       | _ -> error "list-bookmarks: bad command line"
       end
   | Some Metadata ->

cpdfpage.ml

@@ -154,7 +154,7 @@ let change_pattern_matrices_page pdf tr page =
     {page with Pdfpage.resources = change_pattern_matrices_resources pdf tr page.Pdfpage.resources used}
 
 (* Output information for each page *)
-let output_page_info pdf range =
+let output_page_info ?(json=false) pdf range =
   let pages = Pdfpage.pages_of_pagetree pdf
   and labels = Pdfpagelabels.read pdf in
     let getbox page box =
@@ -173,6 +173,28 @@ let output_page_info pdf range =
     and rotation page =
       Pdfpage.int_of_rotation page.Pdfpage.rotate
     in
+      let json_entry_of_pnum pnum =
+        let getbox_json page box =
+          match getbox page box with
+          | "" -> `Null
+          | s ->
+            let a, b, c, d = Cpdfcoord.parse_rectangle (Pdf.empty ()) s in
+              `List [`Float a; `Float b; `Float c; `Float d]
+        in
+        let page = select pnum pages in
+          `Assoc
+            [("Page", `Int pnum);
+             ("Label", (`String (try Pdfpagelabels.pagelabeltext_of_pagenumber pnum labels with Not_found -> "")));
+             ("MediaBox", getbox_json page "/MediaBox");
+             ("CropBox", getbox_json page "/CropBox");
+             ("BleedBox", getbox_json page "/BleedBox");
+             ("TrimBox", getbox_json page "/TrimBox");
+             ("ArtBox", getbox_json page "/ArtBox");
+             ("Rotation", `Int (rotation page))]
+      in
+        if json then
+          flprint (Cpdfyojson.Safe.pretty_to_string (`List (map json_entry_of_pnum range)))
+        else
           iter
             (fun pnum ->
                let page = select pnum pages in

cpdfpage.mli

@@ -1,7 +1,7 @@
 (** Working with pages *)
 
 (** Print page info (Mediabox etc) to standard output. *)
-val output_page_info : Pdf.t -> int list -> unit
+val output_page_info : ?json:bool -> Pdf.t -> int list -> unit
 
 (** Given a function from page number and page to page, a document, and a list
 of page numbers to apply it to, apply the function to all those pages. *)