I would like to use inkscape's command-line actions to pad an image a given amount. I tried

inkscape --actions "export-margin:100;export-do" example.svg

but it doesn't seem to do anything. What's going wrong?

I think that's a bitmap export option, so would work if exporting to png ? 

I see. I need to export/save SVGs with a margin. Any hint on how to do that?

It's something that I can do with a single command line. 

It requires a scripting line in bash / powershell before the command line.

I don't know which OS you are using ?

> I don't know which OS you are using ?

I'm on Linux/zsh, but if it's getting more complex I wouldn't mind switching to a small Python script either. I just have no clue what SVG properties would have to be adjusted.

Ok. For a Single Inkscape command call the following script with resize for a user provided %x and %y

It uses a trick to insert a dummy rectangle in the root, centred with a percentage height and width. 

The percentage would be based on the original document size. 

Usage: pad_svg.sh Sourcefolder Percentage_x Percentage_y

It creates a folder 'out' in the current folder and dumps the output files there. 

In order to pad by user provided values instead of percentages, it would require another command call before this code. That would have to be parsed, and the percentage calculated and fed into this script.

if [ $# -lt 3 ]; then
    >&2 echo "Usage: pad_svg.sh Sourcefolder Percentage_x Percentage_y"
    exit 1
fi

# Create a temp folder
temp_folder=$(mktemp -d -t)
echo $temp_folder

# Make an output folder if does not exist
mkdir -p ./out

# Pad by percentage
percentage_x=$2
percentage_y=$3
#----------------------------------------

# Get only files with an .svg extension in the given folder

for f in $1/*.svg; do 

echo $f

# Test that the file is actually file / exists

test -f $f || continue

# Copy the file to the temp folder

cp $f $temp_folder

# Get just the filename ingoring the path

base_name=$(basename $f)

echo $base_name

# Remove the closing </svg> tag

sed -i '/<\/svg>/d' $temp_folder/$base_name

# Add a framing rectangle which we can resize canvas to

# Work out the values for x and y in the rectangle so we can centre frame horizontally and vertically

rect_x=$(bc <<< "-($percentage_x - 100)/2")
rect_y=$(bc <<< "scale=3;-($percentage_y - 100)/2")

rect_string=$(echo '<rect id="temp_frame_rect" x="'$rect_x'%" y="'$rect_y'%" width="'$percentage_x'%" height="'$percentage_y'%" stroke="green" stroke-width="0.001" fill="none"></rect>')

printf '%s\n' "$rect_string" >> $temp_folder/$base_name

# Replace the closing </svg> tag

echo '</svg>' >> $temp_folder/$base_name

output_name=$(printf '%s\n' "${base_name%.svg}_padded.svg")

echo $output_name

# Create an Inkscape action list with export to the out folder, then run Inkscape on the tempfile

actions_list="select-by-id:temp_frame_rect;object-to-path;fit-canvas-to-selection;delete;export-filename:out/${output_name};export-do"

inkscape --actions=$actions_list $temp_folder/$base_name

done

# Remove the temp_folder
trap 'rm -rf "$temp_folder"' EXIT