Entropy is a fairly easy concept to define, the measure of disorder in a closed system, and a rather difficult concept to grasp, but one that furnishes us with wonderful insights into the way the world around us operates. The amount of entropy in the Universe is ever-increasing, the energy concentrated in our sun is constantly radiating away in light and heat, dissipating into an unusable state, absolute undifferentiation.

Sunflower
Credit: riandreu

Living things form “pockets of resistance” to the force of entropy. They do this through syntropy, or negentropy, which is the entropy we export to reduce our internal entropy; in other words, it’s the waste energy we generate to keep our soma in an organized working state. We collect the sun’s waste energy and use it to organize ourselves through syntropy.

How Much Information Entropy?
Credit: Moi

In Information Systems, entropy, known as Shannon entropy for Claude Shannon, is the measure of uncertainty in a random variable. A coin toss has one bit of entropy for the 50/50 chance of it turning up heads or tails, 0 or 1. A six-sided dice carries three bits of entropy for the possible outcomes it may produce with each roll (1 (000), 2 (001), 3 (010), 4 (011), 5 (100), 6 (101)). The weather has an amount of entropy difficult to quantify, but it varies from location to location. The weather in New York has more entropy than the weather in Southern California because Southern California has a more consistent climate. Similarly, in our first example, if we were dealing with a rigged coin, one that turned up heads more often than tails, then there would be less than one bit of entropy in each coin toss because we would expect heads more frequently than tails.

Web developers put content online to be consumed, but we have little control over the mediums consuming it. Web pages are rendered on mobile phones, printers, televisions, and their semantic content consumed by a variety of bots, each with their own requirements and best-practices for layout. Here I’ll outline three commons solutions to providing a print version of web page content.

Defining Printer-Friendly Design

First we need to define the differences between design for the screen and design for print. Computer monitors and mobile phones are very different media from paper, even when displaying static content. Screens are backlit, while paper is reflective. Web development for the screen must take into account screen resolutions, while presentation on paper must consider page dimensions and toner consumption.

Jennifer Kyrnin has a definitive list of print-friendly attributes, changes that should be made to web content before outputting it to the printed document. Here are the three I find most important, but the list can get much longer depending on your needs:

1. Eliminate dark backgrounds and darken font colors presented over them.
2. Do something with links, either display full URLs, emphasize the text, or remove them altogether.
3. Remove headers, footers, side menus, and advertising.

Server-Side Solutions

One strategy for handling both print and screen layouts of a web page is to have two methods for building the page on the server. For example, w3schools’ “PRINT” button at the bottom of each page opens a new window/tab accessing the same page, but with an “output=print” variable added to the end of the URL, which the VBScript accesses via a GET method. When the VBScript detects the “print” flag, it builds the page without all the extraneous content.