Is there a possible test to check if a PDF file contains text or it is created by scanning paper sheets ?text : plain text that, for example, I can copy & paste while I am reading the PDF. Not searchable / hidden text. Created for example from a wordprocessor.not text : PDF from scanners, containing only JPG or TIFF. There isn't OCR, the PDF contain only images.I cannot use externals tools, because I am working on an embedded system, not linux, not windows, there arent' external libraries. I must work on bare C programming. That is why I prefer a plain function, not depending on external libraries.Is there any info into the PDF header ?My general idea is : read the first 64 Kbytes and try to compress, with a generic library. Pdf with jpg and tiff, scanned from paper, usually compress bad. Pdf of text compress well. Will that work? Are there better methods ?
PDF content : text or graphics?
compression;pdf