From 7916bcfee1938017cb36907ed6f4106a8bb3024c Mon Sep 17 00:00:00 2001
From: John Whitington <john@coherentgraphics.co.uk>
Date: Thu, 4 Aug 2022 18:16:04 +0200
Subject: [PATCH] more

---
 Changes        |  1 +
 cpdfaddtext.ml | 39 +++++++++++++++++++++++++++++++++++----
 2 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/Changes b/Changes
index bb3ab0c..9056eb8 100644
--- a/Changes
+++ b/Changes
@@ -2,6 +2,7 @@
 
 Extended features:
 
+o Add links to parts of text with -add-text
 o Allow -utf8 with -split-bookmarks -o @B.pdf to produce UTF8 filenames
 o -merge-add-bookmarks now works with unicode filenames
 o Better transformation of some annotation types
diff --git a/cpdfaddtext.ml b/cpdfaddtext.ml
index a627600..547cb12 100644
--- a/cpdfaddtext.ml
+++ b/cpdfaddtext.ml
@@ -282,6 +282,7 @@ let extract_url line =
       if rest = [] then error "bad URL syntax in text" else
       (text, url, tl rest)
 
+(* multiple %URL[a|b] *)
 let get_urls_line line =
   let line = explode line in
   let urls = ref [] in
@@ -303,6 +304,8 @@ let get_urls_line line =
     loop line;
     (implode (rev !outline), rev !urls)
 
+ 
+(* Get all URLs for all lines *)
 let get_urls lines =
   let urls = ref [] in
   let linesout = ref [] in
@@ -375,7 +378,7 @@ let addtext
         | Some d -> d
       in
         let unique_fontname = Pdf.unique_key "F" fontdict in
-          let ops =
+          let ops, urls =
             let text = process_text time text (replace_pairs pdf filename bates batespad num page) in
               let calc_textwidth text =
                 match font with
@@ -440,10 +443,12 @@ let addtext
                         match font with
                         | Some f ->
                             ops longest_w metrics (x +. shift_x) (y +. shift_y) rotate (hoffset +. joffset) voffset outline linewidth
-                            unique_fontname unique_extgstatename colour fontsize text
+                            unique_fontname unique_extgstatename colour fontsize text,
+                            urls
                         | None ->
                             ops longest_w metrics (x +. shift_x) (y +. shift_y) rotate (hoffset +. joffset) voffset outline linewidth
-                            fontname None colour fontsize text 
+                            fontname None colour fontsize text,
+                            urls
           in
             let newresources =
               match font with
@@ -454,7 +459,33 @@ let addtext
                     Pdf.add_dict_entry resources' "/Font" newfontdict
               | None -> page.Pdfpage.resources
           in
-            let page = {page with Pdfpage.resources = newresources} in
+            (* Build annotations from URL data (get_urls and some sense of metrics) *)
+            let annot (minx, miny, maxx, maxy) url =
+              Pdf.Dictionary
+                [("/Subtype", Pdf.Name "/Link");
+                 ("/Rect", Pdf.Array [Pdf.Real minx; Pdf.Real miny; Pdf.Real maxx; Pdf.Real maxy]);
+                 ("/BS", Pdf.Dictionary [("/W", Pdf.Integer 0)]);
+                 ("/A", Pdf.Dictionary [("/URI", Pdf.String url);
+                                        ("/Type", Pdf.Name "/Action");
+                                        ("/S", Pdf.Name "/URI")])]
+            in
+            let annots =
+              map (fun (linenum, url, s, e) -> Pdf.Indirect (Pdf.addobj pdf (annot (0., 0., 100., 100.) url))) urls
+            in
+            let newrest =
+              if annots = [] then page.Pdfpage.rest else
+                let existing =
+                  match Pdf.lookup_direct pdf "/Annots" page.Pdfpage.rest with
+                  | Some (Pdf.Array a) -> a
+                  | _ -> []
+                in
+                  Pdf.add_dict_entry page.Pdfpage.rest "/Annots" (Pdf.Array (annots @ existing))
+            in
+            let page =
+              {page with
+                 Pdfpage.resources = newresources;
+                 Pdfpage.rest = newrest}
+            in
               if underneath
                 then Pdfpage.prepend_operators pdf ops ~fast:fast page
                 else Pdfpage.postpend_operators pdf ops ~fast:fast page