Disliking PDF

I am no fan of PDF as a file format, particularly when compared to PostScript, its older rival. There are many reasons to dislike PDF, such as:

It is the finally issue to which I wished to draw attention. Here is a PDF file. It is short, simple, and invalid. It contains the three words "Do", "not" and "vote" in three different fonts. The font used for "not" is invalid, so might not be displayed. But many PDF viewers give no warning, and display the text "Do vote", negating the (probable) meaning. A quick test gives:

chromium 75No warning, "Do not vote"
evince 3.28.2No warning, "Do vote"
gs 9.25Many warnings, "Do not vote"
gv (gs 9.25)One warning, "Do not vote"
firefox 68No warning, "Do vote"
okular 1.3.3No warning, "Do vote"
preview MacOS 10.13No warning, "vote"
safari MacOS 10.13No warning, "vote"
xpdf 3.04Four warnings, "Do vote"

So three completely different renderings with no warnings accompanying them. Similar fun can be had if one attempts to write text with no current font defined at all (rather than attempting to use as a built-in font something which one has no reason to believe will be built in, as this example does).

PDF's advantages

So what are some of the advantages of PDF over PostScript?

But to any Computer Scientist, PDF will always be dull. A Mandelbrot Set in PDF is just an image (unless one embeds a JavaScript object, which is surely cheating). A Mandelbrot Set in PostScript is probably a program which generates the set when run.

Both PostScript and PDF are trademarks of Adobe.