Questions and postings pertaining to the usage of ImageMagick regardless of the interface. This includes the command-line utilities, as well as the C and C++ APIs. Usage questions are like "How do I use ImageMagick to create drop shadows?".
You PDF is likely vector based-- if so you'll need a PDF editor to add text to the image. If you intent was to rasterize the image and annotate it, use super-sampling like this: