Color Reactiveness on the Desktop
Here's how to go about constructing a control panel to handle behavior sets for color-reactive desktop elements.
The user should be presented with a list of potential “states” (like Busy, Idle, Sleeping, Error, etc.) and then be given the ability to map the color of their choice to each state.
The Color Transition Table allows the user to specify the physical behavior of the Lamp or Beacon. A whole row of “C” means simply “for this behavior, the color always remains clear”. A repeating sequence of BRBRBRBRBRBR would make the lamp flash rapidly between blue and red, over and over again. To slow down the rate of blinking, use a sequence like BBBBRRRRBBBBRRRR.
The Color Transition Table also allows the user to specify the sequence of colors it will show to indicate each specific state. If you wanted to get the user's attention, you would probably want to make the lamp or beacon flash rapidly. This can be done by alternating the sequence of colors, like drum beats in a song. To use an analogy, the lights on a police car can be thought of as color-reactive elements. When the police car is in a state called “pursuit”, its behavior is red, blue, red, blue, red, blue.
To make a lamp or a beacon flash like it is on fire, a sequence like ROYOROYOR will make it strobe from red to orange to yellow to orange, repeatedly.
The Color Transition Table allows for a tremendous amount of flexibility when dictating the precise behavior of color-reactive desktop elements. By simply changing the entries in the table, you can do everything from solid colors to wild rainbow effects just by playing with the order of colors for each state.
An example behavior set is shown in Listing 1. This is what the behavior set would look like if you wanted:
Clear color for idle
Blue for sleeping
Violet for low CPU usage
Red for moderate CPU usage
Orange for heavy CPU usage
Yellow for severe CPU usage
Slow blinking green/clear for attention
Fast blinking red/clear for error
Normal blinking aqua/clear for busy
Using color as a function of CPU usage, a behavior set might look like this:
Extremely CPU-intensive: red
As a function of process state, it might be defined this way:
Segfault/dead stop: red
Waiting for user input: blue
A pager program or e-mail checker could be collapsed into a beacon that would turn green whenever you had a new message waiting. A packet sniffer could be made to flash red whenever suspect ICMP packets are received. An FTP client could use its lamp to indicate the various stages of connection to a host or the progress of a file transfer.
I propose that the GNOME desktop should not only feature this design innovation, but use it prominently in the general layout of each window as per the recommendations given here. Let's go for it! It is a simple concept to understand, simple to implement, and its function ultimately justifies its inclusion.
Since I first wrote this article, GNOME Developer Eckehart Burns has developed a color-reactive Lamp/Beacon widget to the GNOME UI library which is currently part of the GNOME CVS tree. GNOME application coders now have the ability to incorporate CR into their applications at their discretion.
All listings referred to in this article are available by anonymous download in the file ftp.linuxjournal.com/pub/lj/listings/issue58/3039.tgz.
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