Account for dimensions of background pdf

tools/README.md

@@ -6,11 +6,12 @@ The following binaries are required running these tools:
  * ssh
  * scp
  * convert or rsvg-convert
+ * optional: ghostscript and pdfinfo to account for original pdf dimensions
 
 If you are using a Debian-based Linux system, the following command should
 install all requirements:
 
-	sudo apt-get install python3 librsvg2-bin pdftk openssh-client
+	sudo apt-get install python3 librsvg2-bin pdftk openssh-client ghostscript
 
 ## rM2svg
 

tools/exportNotebook

@@ -5,6 +5,7 @@
 # - convert (imagemagick)
 # - pdftk (pdftk)
 # - rsvg-convert (optional, to avoid rasterizing of lines)
+# - gs & pdfinfo (optional, to account for original pdf size)
 
 if [[ $# -eq 0 ]] ; then
     echo "Usage: ./exportNotebook (Partial)NotebookName AdditionalrM2svgArguments"
@@ -47,8 +48,32 @@ echo "Exporting notebook ${filename} ($(wc -l "${tmpfolder}"/*.pagedata | cut -d
 
 if [ -f "${tmpfolder}"/*.pdf ]
 then
+    ln -s "${tmpfolder}/"*.pdf "${tmpfolder}/background_original.pdf"
     echo "Found underlying document PDF, using as background."
-    cp "${tmpfolder}/"*.pdf "${tmpfolder}/background.pdf"
+
+    if command -v "gs" > /dev/null && command -v "pdfinfo" > /dev/null
+    then
+        # Read PDF dimensions for scale correction
+        size=$(pdfinfo ${tmpfolder}/background_original.pdf | grep "Page size" | awk '{print $3,$5}')
+        width=$(echo ${size} | cut -f1 -d " ")
+        height=$(echo ${size} | cut -f2 -d " ")
+
+        # Calculate new width and necessary offset (rM dimensions: 1404x1872)
+        new_width=$(echo "scale=5; ${height} / 1872 * 1404" | bc)
+        offset=$(echo "scale=5; ${new_width} - ${width}" | bc)
+
+        echo "Original PDF dimensions are (${width}x${height}), correcting by offset of ${offset} to fit rM foreground."
+
+        # Add offset to background.pdf to match foreground dimensions
+        gs -q -sDEVICE=pdfwrite -dBATCH -dNOPAUSE -sOutputFile=${tmpfolder}/background_with_offset.pdf \
+        -dDEVICEWIDTHPOINTS=${new_width} -dDEVICEHEIGHTPOINTS=${height} -dFIXEDMEDIA \
+        -c "{${offset} 0 translate}" \
+        -f "${tmpfolder}/background_original.pdf"
+
+        ln -s ${tmpfolder}/background_with_offset.pdf ${tmpfolder}/background.pdf
+    else
+        ln -s ${tmpfolder}/background_original.pdf ${tmpfolder}/background.pdf
+    fi
 else
     # Getting template files
     sort -u "${tmpfolder}"/*.pagedata | while read -r tpl; do
@@ -73,7 +98,7 @@ fi
 filename=$(basename -s .pdf ${filename//\"/})
 
 # Use multistamp instead of multibackground to preserve transparency
-pdftk "${tmpfolder}"/foreground.pdf multistamp "${tmpfolder}"/background.pdf output "${filename}.pdf"
+pdftk "${tmpfolder}"/background.pdf multistamp "${tmpfolder}"/foreground.pdf output "${filename}.pdf"
 
 filesize=$(ls -la "${filename}.pdf" | awk '{print $5}' | numfmt --to=iec-i --suffix=B --format="%.3f")
 echo "Written ${filesize} to ${filename}.pdf"