PDF PostScript filter

Webservice for editing PostScript in PDFs on the fly, implemented purely in TypeScript.

Setup

npm install
npm run build

Once successfully built, deploy the public folder as-is.

Custom filters

Filters are always executed for every line of PostScript in the PDF, and consist of two parts:

• Selection function: decides whether a line should be edited or not
• Mapping function: function to apply to each line where the selection function returned true

Example filter

Selection function:

// check wether the line includes a copyright sign
return line.includes("Td [(\\251)]");

Mapping function:

// replace all PostScript text elements with empty elements (still having the same length)
return line.replace(/\([\w\\&,]+\)/g, m => `(${" ".repeat(m.length)})`);