Add Bates Numbers to PDF Pages Add Bates numbers to every page of a PDF document.

The tool utilizes the pdf-lib library to load and manipulate PDF documents client-side, ensuring confidentiality and security. When a file is dropped into the tool, it is loaded into a PDFDocument object using the `load` method with the `ignoreEncryption` option set to true. This allows the tool to access the document's pages and apply Bates numbering. The tool then embeds the Helvetica font into the document using the `embedFont` method, which is necessary for rendering the Bates numbers.

The Bates numbers are generated by iterating through each page and applying the formula: prefix + padded number + suffix. The padding is achieved using the `padStart` method, which adds leading zeros to the specified digit count. Text positioning is calculated based on page dimensions and font metrics, with six possible positions supported: bottom-right, bottom-center, bottom-left, top-right, top-center, and top-left. For each position, the x and y coordinates are calculated accordingly, taking into account a margin of 30 pixels to avoid overlapping with document content.

The tool uses the `drawText` method to render the Bates numbers on each page, with a font size that is configurable from 6pt to 20pt. The text color is set to a subtle gray (0.3, 0.3, 0.3) using the `rgb` function from pdf-lib, which helps avoid interfering with document content. Once all pages have been processed, the modified PDFDocument object is saved to a byte array using the `save` method, and a blob URL is created to facilitate downloading the resulting PDF file.

The tool's client-side processing relies on browser APIs such as `arrayBuffer` and `URL.createObjectURL` to handle file loading and saving. The React library is used for building the user interface, with components like `FileDropzone`, `InputWithHelp`, and `SelectWithHelp` providing a user-friendly experience for customizing Bates numbering options. By leveraging these technologies, the tool provides a robust and customizable solution for adding sequential identification numbers to PDF documents.