Rotate All Pages in Your PDF Online Rotate all pages.

The tool works by using the `pdf-lib` library to load and manipulate PDF documents in the browser. When a user drops a PDF file into the interface, the `handleFile` function is triggered, which loads the PDF document into memory using `PDFDocument.load`. This process involves reading the PDF file as an array buffer and then parsing it into a `PDFDocument` object, which represents the document's structure and content. The `ignoreEncryption` option is set to `true` to ensure that encrypted documents can be loaded.

Once the document is loaded, the tool uses the `getPageCount` method to determine the number of pages in the document. When the user selects a rotation angle and clicks the "Rotate All" button, the `process` function is called, which applies the rotation to each page using the `setRotation` method. This involves calculating the new rotation angle for each page by adding the selected angle to the current angle and taking the result modulo 360 degrees. The rotated pages are then saved as a new PDF document using the `save` method, which generates a binary blob that can be downloaded directly from the browser.

The tool's interface is built using React, with memoized functions like `handleFile` and `process` to improve performance by reducing unnecessary re-renders. The interface also features a responsive design, with CSS classes like `glass-card` and `space-y-6` used to style the layout and appearance of the components. When the user clicks the "Download" button, the tool uses the `URL.createObjectURL` method to create a URL that can be used to download the rotated PDF document, which is then triggered by simulating a click event on an anchor element.