Dumb PDF question

[almoststew1990]

I spend a lot of my working day looking at PDFs that are say 1MB to 20MB big of drawings prepared in CAD. My work laptop is pretty meh but even so I don't understand how a 20mb PDF can take several seconds to load, and it will do it in chunks or by layers as I pan and zoom with the PDF saved on some kind of SSD? Feel free to use up 20MB of RAM and or 20MB of VRAM and just display everything at once!

What's the science / magic behind PDFs?

 

[rp2000]

Don't think of it as a file type. All files with the extension .pdf are not created equal.

All sorts of files can be "converted" or output to pdf. A 2 line notepad file turned into a pdf is gonna be a lot less complex than a 50mb CAD file created in AutoCAD or something. It's normal when you zoom in the detail increases depending on the source and it only loads the details when you zoom in or pan around.

I imagine your laptop would only perform marginally better opening the source file natively with the very expensive software that it was originally authored in. I.e. if it was a .dwg file created in AutoCAD, prior to being converted to a PDF file.

Really basic answer and some jargon may be wrong!. The rest is to do with rendering of fonts, vectors, postscript and other techhie stuff that you can read about properly elsewhere.

PDF - Wikipedia

en.m.wikipedia.org

rp2000