Why is it possible to write pdf files but not to read it?

[vinb]

Hi all,
I'm having the question you see in the title.
I don't understand why its easy to write a pdf file, but that you have to use 3rd party libs to read it.
Can someone please explain this to me?

[tobias.hunger]

Mostly this is due to the PDF format. It is pretty simple to write, but getting useful information back out is much harder. It is intended to produce exact representation of pages, so it basically (I am simplifying a lot!) "put the letter 'a' at position x and y and make sure it is w units wide and h units high, using font f". So it is really hard to turn the contents of a PDFs back into meaningful objects like text.

Plus printing is way more common than parsing PDF contents, so it makes more sense to have the first in a general purpose library like Qt.

[vinb]

Hi Tobias Hunger,

Thanks for your reply!
Then i will comfort me with QProcess and lp at the moment.