Set Custom Background Color for PDF Pages Add a background color to all PDF pages.

The tool works by utilizing the pdf-lib library to create a new PDF document with colored backgrounds. When a user uploads a PDF file, it is loaded into memory as an array buffer and then passed to pdf-lib's load function, which returns a PDFDocument object. This object contains information about the PDF's structure, including the number of pages. The tool then creates a new PDFDocument object using pdf-lib's create function, which will serve as the container for the modified pages. For each page in the original document, it embeds the source page into a new page of the same dimensions within the new document, draws a full-page rectangle with the selected RGB color and opacity, and then overlays the original page content using drawPage.

The hexToRgb function is used to convert the user-selected hex color value to an RGB object, which is then normalized to floats in the 0-1 range as required by pdf-lib. The opacity parameter controls the alpha value of the background rectangle, allowing for adjustable transparency. When the process function is called, it saves the new PDF document to a blob, which is then used to create a downloadable URL using the URL.createObjectURL method. The resulting PDF contains the original content and layout, but with the added colored background on each page. This approach ensures that the tool can handle PDFs with multiple pages and preserve the original formatting while adding visual distinction through colored backgrounds.

pdf-lib's embedPages function is used to embed the source pages into the new document, allowing for precise control over page dimensions and content positioning. The drawRectangle method is then used to draw the colored background rectangle on each page, taking into account the selected RGB color and opacity values. By leveraging pdf-lib's capabilities and carefully managing the conversion between hex and RGB color representations, the tool provides a reliable and efficient way to add colored backgrounds to PDF documents while maintaining their original content and layout. The use of array buffers and blobs enables efficient handling of binary data, ensuring that large PDF files can be processed without significant performance degradation.