Why Adobe is Still (Partly) Evil

There are really two types of fonts, outline and bitmap.

Outline fonts are represented internally by vectors, or lines, which specify the outline of the fonts. Because of these, they are dynamically scalable (you can change the size of them however you want), and they will appear the same way they did at a smaller size. Professional typesetting requires fonts that are designed for a given size; while the outline of a scaled font will be true to its original size, it won’t necessarily look right at that size. However, for daily use, such fonts will work just fine. Adobe is the great champion of such fonts, being involved in the development of OpenType fonts (along with Microsoft, if that tells you anything), and also being the inventors and maintainers of PostScript fonts.

Bitmap fonts, on the other hand, are represented by pixels. They’re essentially a grid of pixels, and those which are supposed to be colored are colored, while those which are not supposed to be colored are not. This method has the disadvantage that dynamic scaling is not really possible; if you blow up a 10-point font to 20-points, it will look pixelated and otherwise wrong. On the other hand, if your bitmaps are generated by clearly stated rules (like in Donald E. Knuth’s superb font program Metafont), you can dynamically produced a large quantity of different sizes, all of which were designed for a particular size, and you thus reap the normal benefits of outline fonts. Unfortunately, most common programs (except for the superb TeX, LaTeX, and friends), are unable to work with such programmed bitmap fonts. (TeX and LaTeX are quite happy working with either.)

Both bitmap and outline fonts can be used in pdf documents. pdf, or “portable document format,” is a widely used standard maintained by Adobe, authors of the standard as well as its more mature and complex cousin, PostScript. pdf documents can be created with Adobe’s own software; mostly, however, I create them with free tools, most often pdftex.

Being a Linux user, I rarely use Adobe’s own pdf reader, Acrobat Reader (which I’ll henceforth call acroread, that being the command which invokes it). Linux contains large numbers of alternative readers, most of which I consider easier to use and better than acroread. My personal favorite is the basic xpdf; however, there are also kpdf, evince, and others available. Essentially, when you’re running a free operating system, there is never any real need to download a nonfree pdf reader, so I simply don’t ever run one.

Recently, though, I was at work and happened to open a document which contained the numerals of the dozenal package, numerals which I designed in the aforementioned awesome and way-ahead-of-its-time Metafont language. They looked perfectly fine in all the free pdf viewers I have thus far mentioned; however, at work I don’t have the privilege of using Linux, and therefore opened them in acroread. They looked terrible. Odd, I wondered; why are all these FOSS pdf readers perfectly able to display my bitmap fonts with admirable clarity, but Adobe’s own acroread unable to do so?

Take a look at a couple of screenshots. Here (courtesy of Outline and bitmap fonts compared) is a document with outline fonts on one side and bitmap fonts on the other. I have opened it here in acroread version 7 and taken the screenshot with the GIMP (2.6, Windows version, since I still don’t have acroread installed on any of my Linux systems).

Screenshot comparing bitmap and outline font resolutions in acroread

Now, the resolution is pretty bad on both sides, but that’s the screenshot’s fault, not acroread’s. However, even in this low quality, you can still clearly see that the bitmap side is significantly lower quality than the outline side. Now, let’s take a look at it displayed in my favorite reader, xpdf; this screenshot was taken with xwd, which I have bound to F4 (and to a menu button) on my fvwm desktop running on Debian Linux:

Comparison of outline and bitmap font display in xpdf, running on Debian Linux.

Clearly, both sides are displayed with equivalent accuracy. This is true even in other Windows-based viewers; e.g., the excellent GSview is able to render both sides of this document without any problems:

Screenshot comparing bitmap and outline fonts in GSview, running in Windows.

If anything, the bitmap font side looks better than the outline side in this example. So both bitmap and outline fonts can be displayed in pdf files with equal resolution without trouble. There is no reason why this shouldn’t be so; the aforementioned Outline and bitmap fonts compared notes that

[i]n principle, given adequate resolution, the screen preview quality of documents set in bitmap fonts, and set in outline fonts, should be comparable, since the outline fonts have to be rasterized dynamically anyway for use on a printer or a display screen.

By “rasterized,” they mean that the outline fonts have to be turned into bitmaps to be displayed anyway. Outline fonts require an extra step, called “rasterization,” to make them into bitmaps in order to display them on the screen, or print them onto paper. So Adobe is here displaying bitmaps and bitmaps, not outlines and bitmaps; yet the bitmaps which don’t need that rasterization are terrible, while those that do are excellent. What gives?

The reason is that Adobe has crippled acroread deliberately to prevent its displaying non-Adobe-type fonts properly. There is no other reasonable explanation for this performance. Adobe is responsible for two popular outline font formats and zero popular bitmap font formats; therefore, they attempt to promote their own font formats by making their extremely common pdf reader display other, non-Adobe-supported font formats badly. People think that this is the font’s fault, not Adobe’s, and consequently use Adobe’s own fonts rather than bitmap ones.

This, my friends, is evil.

The answer? Don’t use Adobe acroread. There are plenty of alternatives, whether your operating system is free or not. Mac OS-X, of course, can run any X-based application with the proper dependencies installed. If you’re using a free operating system, utilize one of the excellent pdf viewers I mentioned above, or even another if you want. If you run Windows, the aforementioned GSview will be your best choice, though there are other possibilities, such as Sumatra PDF.

The bottom line is to avoid giving our support to this large software company that is attempting to abuse its power to induce people to unwittingly believe that a perfectly valid and useful font type doesn’t work as well as the ones which it produces. In other words, it’s lying, and there’s no excuse for that, nor is there any reason to support it. Adobe is still (partly) evil; let us all attempt to support only its non-evil projects, and not its evil ones.

Praise be to Christ the King!