PDF Infix Editor: Text Reflow Editing Explained

The term 'infix' in PDF editing refers to the ability to modify text within an existing document flow — inserting, deleting, or changing words while the surrounding content adjusts naturally. Traditional PDF editors treat text as fixed-position blocks: if you add or remove text, it doesn't automatically reflow into the available space, potentially creating gaps or overlaps. PDF infix editors attempt to solve this by reflowing text like a word processor, making content changes feel more natural and producing cleaner output. Iceni Technology's Infix PDF Editor was the most well-known tool in this category, offering a word-processor-like editing experience for PDFs on Windows. The technology behind infix editing is complex because PDFs are fundamentally a fixed-layout format — they describe exactly where each character appears on the page rather than describing text flow like HTML or Word documents. Reconstructing text flow from a fixed layout and then editing within that flow while maintaining the original formatting requires sophisticated algorithms. Modern browser-based editors like pdfeditor.website have incorporated similar text editing capabilities, allowing users to click on existing text elements and modify them while preserving the surrounding document layout. While the reflow behavior may not be as sophisticated as dedicated infix editors for every document type, it handles the most common editing scenarios effectively and adds signing, conversion, and page management tools that infix editors typically lack.