Would you mind listing a few? I ask because, if my memory serves correctly, the only thing DVI ever accomplished for me was to make me want to poke my eyes out.
I'll refrain from elaborating on the difference between those (it's probably best if I don't), except to say that my jaws will probably shatter the floor if you tell me you don't see the difference. :-)
(Probably worth saying that I have the same issue with PS; it's not just DVI. I do sometimes wonder if I'm the only one who sees these.)
On the other hand, given Knuth's goals of not having to re-do all the work when the technology changes, METAFONT is an “end-to-end” solution: starting with the font design (at a higher level than the outlines that are ultimately shipped for vector fonts), it goes all the way to generate the actual pixels for a given resolution (like 600 dpi or 2400 dpi), resulting in bitmap fonts (pre-rasterized) rather than vector fonts (rasterized on-the-fly by PDF viewer).
There are a few consequences of these differences, for on-screen viewing:
• Computer monitors are very low-resolution devices (even the most high-end “retina display”, “4K” or whatever) compared to print. There are several tricks required to make text look good on screen (see e.g. the chapters at rastertragedy.com for details): things like anti-aliasing/grayscaling (using pixels that are neither black nor white) and subpixel-rendering (using individual RGB subpixels that make up each screen pixel).
• There's a conflict between thinking of on-screen viewing as serving to approximate to what the printed page will look like, versus allowing deformations or even re-positioning characters from where they'd be printed, to simply look better on screen.
But all of this has nothing to do with the DVI format, ultimately (which is just an efficient encoding of the page layout, i.e. what characters from what fonts go where on the page). It's just that (1) many DVI viewers tend to use bitmap fonts for historical reasons, resulting in poor on-screen viewing, (2) some DVI viewers use their own libraries for rendering instead of using the best font-rendering libraries available on the system.
• Even if using a bitmap font, the DVI viewer has a choice: (1) it can take the bitmaps that were generated for a certain resolution (typically for print, so something like 600 dpi which is probably higher than your screen resolution), and try to render those bitmaps at the number of pixels available (with the typical problems that result), or (2) it can try to ask METAFONT to run again to generate the fonts at whatever low resolution is appropriate for your monitor (but still without anti-aliasing and subpixel rendering, as MF was designed for higher-resolution devices and doesn't bother with all that). DVI viewers seem to always take the first option, probably to prevent the user's disk from filling up with lots of bitmap fonts for every possible zoom level. So the font rendering ends up sub-par. If you print it on a high-resolution device the output will be fine.
• For screen display, the DVI viewer could choose to look up and use the corresponding vector font.
• Finally, the DVI viewer could just convert to PDF (with dvipdfm or whatever) and have the same on-screen experience as with something that was originally a PDF file. In fact, on my current macOS system, the two DVI-viewing options I have (Skim and TeXShop's viewer) both seem to do exactly that internally, and the output is excellent.
Given that dvi doesn’t involve pixels, and lets you position any character anywhere on the page, with precisely known rules for rounding into resolution-specific device-space, you’ll have to be more specific about what you’re blaming dvi itself for.
The "output device" is... my monitor?
The toolchain is TeXLive for generating the files, and the usual viewer for each file type on Windows (Acrobat Reader for PDFs, and Evince for DVI). If you think it's Evince's fault I'd love to hear better alternatives, because I haven't found a single viewer that views DVIs any differently. And for input files, you can generate files via LaTeX pretty easily:
% DVI: latex thisfile.tex
% PDF: pdflatex thisfile.tex
\documentclass{article}
\usepackage{lipsum}
\begin{document}\lipsum\end{document}
Remember, though, at the end of the day, I'm just an end-user. I just know that every time I try to view DVI and PS files I have to tear my eyes out, and that I don't have this struggle with PDFs. I neither know which particular person or place in the pipeline to assign the blame to, nor does knowing that make it any easier for me to read the text...
Oh, if that's the problem, then please just point to a better viewer for yesterday's display technology. Or even a decade ago's. I'll find you an older monitor from whatever era you had a good viewing experience on and try it on that. Because I'm one hundred percent sure an older display technology is not going to make it look better. You can see above that above pointed out that it's looked awful since 2003. I can vouch that it's consistently been awful since over a decade ago, and PDFs have consistently been fine... on every kind of display and resolution I've tried. I've absolutely never, ever had a good experience viewing DVIs.
But that's nothing to do with DVI itself; it's entirely the responsibility of the renderer.
Secondly can you please define ‘tear my eyes out’? You’ve not provided any attempt any any technical description of what it is you’re experiencing. How is anyone supposed to help you when you don’t say what the problem is?
I also remember the horrible font rendering mentioned elsewhere in the thread, but that would go away when printed or converted to PDF/PS, so I always assumed it was a bug in the viewer.
That said, I always admired how small .dvi files were in comparison to PDF, and that they loaded much faster. Kudos!
I have some .dvi files lying around from 2009, but trying to open them with evince results in
kpathsea: Running mktexpk --mfmode / --bdpi 600 --mag 1+0/600 --dpi 600 aebx12 mktexpk: No such file or directory
and 'apt search mktexpk' doesn't find anything.
So, can't open DVIs anymore, it seems :(
Moving to position is just `123 456 Td`. Placing a string at current position is just `(ABC) Tj`. Placing each glyph at different positions is just `[12 (A) 34 (B) 56 (C)] TJ`. I can do minor edits in PDF using just vim and qpdf.
Can you please write a few details about that workflow? What do you do and how? I used to create .ps "by hand" (actually writing scripts) but I've never tried to start from PDF and then edit. How do you "remove compression, object streams and whatnot"? And some useful references (for those Tj TJ etc).
> QPDF is capable of creating linearized (also known as web-optimized) files and encrypted files. It is also capable of converting PDF files with object streams (also known as compressed objects) to files with no compressed objects or to generate object streams from files that don't have them (or even those that already do). QPDF also supports a special mode designed to allow you to edit the content of PDF files in a text editor. For more details, please see the documentation links below.
$ qpdf --stream-data=uncompress input.pdf output.pdf
The reference is well Adobe's official PDF reference downloadable from its website.
PDF also supports PostScript fonts, which are already compiled for your printer.
Still, DVI is simpler for many uses. I think PDF is too complicated.