How to Extract PDF Coordinates for Signature Placement in C# (Without Uploading Your Files)

If you've ever tried to programmatically place a signature box on a PDF using iText7, you know the pain: you need exact llx , lly , urx , ury coordinates — and getting them right is a tedious, trial-and-error nightmare. You either hardcode guesses, write throwaway debug code, or upload your document to some random online tool (and hope it's not storing your sensitive contracts). There's a better way. The Problem iText7 uses a coordinate system with the origin at the bottom-left of the page. That means Y increases upward — the opposite of what you see visually on screen. So when you write something like: PdfFormField signatureField = PdfFormField . CreateSignature ( pdfDoc , new Rectangle ( llx , lly , width , height )); ...you're flying blind unless you know exactly where those coordinates map to visually on the page. Eyeballing it? You'll redeploy 10 times before it lands right. The Workflow That Actually Works Instead of guessing, here's the approach: Load your PDF locally in a visua