Thursday, November 6, 2008

Content and Presentation: Not Independent

One would like to believe that content decisions and presentation decisions are independent, but they are not. If I want to get a point across, do I present it in prose, as a code example, as a diagram, as a picture, or in some other way? If I want to focus a reader's attention on a particular aspect of a code example, do I change the font style of the relevant text (e.g., to bold or italic), the font background (i.e., to make it look like it's highlighted), or the font color? Or do I leave the font alone, give each line in the code example a number, then use prose before or after the example to describe what I want my readers to see? Depending on exactly what I want to do, I make different decisions. For recent examples, check out the code listings on one of the pages of a recent C++ article I published.

Speaking of code listings, one of the most important presentation decisions I have to make involves code formatting. Decisions on indentation and line breaks are critical, and my experience over many years with a number of publishers is that letting anybody edit my code examples is a sure way to publish broken code. (When I was a columnist for C++ Report, I had to fight over every column with some ninny who had "editor" on his business card and hence felt qualified to edit what I wrote, notwithstanding the fact that he didn't know C++ and was unable to understand what I was writing about.) In retrospect, this may be why I've become so accustomed to producing camera-ready copy: it avoids my having to verify that what I wrote is what ultimately gets published. I'm not perfect, of course, and my books' errata lists provide ample testimony to that, but my experience is that I am much more careful about what goes out with my name on it than anybody else.

One of the places where authors must make critical presentation decisions involves content that is dependent on the capabilities of the output device being used to present the content. For example, here's a table I used in a recent article:

Actually, that's what was published. What I submitted looked a lot nicer, in my opinion:

But consider how this table would "appear" if rendered as speech. (For an example of how a table can sound, click on the "listen" link at the top of Mike Hendrickson's "State of the Computer Book Market" blog entry from February 22, download the mp3, and start listening about 3 minutes into the audio stream.)

As an author, I know that the point of the table is to demonstrate that the "empty" objects I'm discussing in the article may be quite large: up to several thousand bytes. The table is a good way to show that to readers, but for listeners, I'd omit the table and use a prose summary instead. In fact, I already have such a summary in the article:
If such objects are not optimized away, Table 1 demonstrates that their size could be significant (up to many thousands of bytes per feature set), an artifact of the use of virtual inheritance in the current implementation.
For an audio stream, I'd simply omit the table and modify the text above as follows:
If such objects are not optimized away, their size could be significant (up to many thousands of bytes per feature set), an artifact of the use of virtual inheritance in the current implementation.
This suggests another feature I want to have as an author: conditional content. I want to be able to say:
  if (rendering for a print device)
produce this text and show this table
produce this other text and don't show the table
In both cases, the conceptual content is the same. It's the way that information is presented that differs, and it's a decision I, as an author, am best in a position to make. (If I could find an editor who'd make such decisions for me such that I'd be happy with the results of the decisions, I'd gladly turn such decision-making over to him or her. As they say in the old movies, alas, good help is hard to find.)

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