scan2pdf: be explicit about output size and units

diff --git a/scan2pdf b/scan2pdf
index 908a722b2e1a7231989d9aa01877cbe3f1b527f1..0dc7dc5eeba415a68ff7c9bac6f330af93e1147c 100755 (executable)
--- a/scan2pdf
+++ b/scan2pdf
@@ -61,6 +61,8 @@ convert \
     -colors 32 \
     -black-threshold 60% \
     -fuzz 20% -fill white -opaque white \
+    -units PixelsPerInch \
+    -density "$RESOLUTION" \
     -extent "$((RESOLUTION * 17/2))x$((RESOLUTION * 11))" \
     -compress zip \
     "$OUTFILE"