pkgs: add watermark

2 files changed, 38 insertions, 0 deletions

diff --git a/pkgs/default.nix b/pkgs/default.nix
index 649c9c1..f4712ce 100644
--- a/pkgs/default.nix
+++ b/pkgs/default.nix
@@ -31,6 +31,8 @@ super: let
       };
       wallpapers = super.callPackage ./static/wallpapers {};
     };
+
+    watermark = super.callPackage ./watermark {};
   };
 in
   self
diff --git a/pkgs/watermark/default.nix b/pkgs/watermark/default.nix
new file mode 100644
index 0000000..6188ddb
--- /dev/null
+++ b/pkgs/watermark/default.nix
@@ -0,0 +1,36 @@
+{
+  writeShellApplication,
+  coreutils,
+  imagemagick,
+  pdftk,
+}:
+writeShellApplication {
+  name = "watermark";
+  runtimeInputs = [coreutils imagemagick pdftk];
+  text = ''
+    if [[ $1 == --help || $1 == -h ]]
+    then
+      echo "usage: watermark <receiver> <target> <output>"
+      exit 0
+    fi
+    receiver="$1"
+    target="$2"
+    output="$3"
+    dir=$(mktemp -d)
+    pdftk "$target" burst output "$dir"/
+    for page in "$dir"/*.pdf
+    do
+      magick -density 150 "$page" -flatten "$page".jpg
+      magick -size 280x160 \
+             xc:none \
+             -fill '#50505050' \
+             -pointsize 25 \
+             -font Dejavu-Sans \
+             -gravity NorthWest -draw "text 20,20 '$(date +%Y-%m-%d)'" \
+             -gravity SouthEast -draw "text 10,30 '$receiver'" \
+             miff:- \
+        | magick composite -tile - "$page".jpg "$page".jpg
+    done
+    magick "$dir"/*.jpg "$output"
+  '';
+}