Building PDF Stamp Placement Without a Framework — Click to Place, Drag to Move

All tests run on an 8-year-old MacBook Air. Sign & Fill lets users click anywhere on a PDF page to place a stamp or signature image — then drag it to the exact position before committing. No PDF form framework. No annotation API. Just a coordinate system and a content stream injection. The coordinate problem PDF coordinates start at the bottom-left. Canvas/screen coordinates start at the top-left. Every click position needs conversion: function screenToPdfCoords ( clickX : number , clickY :