Is PDF a raster format or a vector format?
PDF supports both raster (bitmap) and vector (line) formats. When a PDF is created by printing from a vector-based application such as AutoCAD or an illustration program, the resulting PDF contains vectors describing all the lines, arcs, and shapes in the drawing. The output can be scaled with no loss of resolution, and viewers can zoom in on the lines in the drawing without seeing any ‘jaggies”. If a scanned image is converted to PDF (such as an existing paper drawing that has been scanned) then the resulting PDF image is a raster image. Zooming in will expose the individual pixels. Raster and vector formats can be combined in the same document if some pages are printed directly and others are scanned. The formats can also be combined on the same page, as when a raster image is imported into a CAD file and then printed along with vectors on the same page.
