Roaming Lines is a screensaver module to be used with Berkeley Systems' After Dark package. As its name suggests, Roaming Lines puts a number of bouncing, roaming lines on the main monitor. Each line is followed by a tail with Moire patterns. If the screen depth is four bits or higher, the lines are drawn in rainbow colors. And now, in version 1.2, if your system supports sound, the roaming lines make a "swish" sound when they pass through each other.
To calculate the movement of the lines, Roaming Lines places each lines' two endpoints inside an invisible wandering box, and randomly chooses velocities for each endpoint and for each box. When an endpoint collides with an edge of its box, the endpoint bounces off in a new, randomly chosen direction. When an invisible box hits the edge of the main monitor, the box bounces off the edge in a random direction.
The control panel allows you to vary the number of lines from one to five, the length of the tails from zero to one hundred (zero meaning each line is drawn alone, with no trailing tail), and the size of the wandering box from 25x25 to 240x240 - a smaller box makes the lines smaller, faster, and bouncier.
From the control panel you can also adjust the volume of the swish sound. The swish sound is designed to make sense when there are a number of small roamers with very short tails speeding around the screen. For bigger roamers, the sound loses its effect, and you'll probably want to turn the volume all the way to down.
When you press the "Other Options..." button in the control panel, you are presented with the following dialog box.
Checking "Dissolve screen" makes the screensaver blank the screen by blacking out random little squares, one at a time, as quickly as possible.
Checking "Xor tails" draws the tails in 1-bit xor mode, so that instead of white drawn over white remaining white, white on white shows up black. Xor mode works properly only in black and white, so lines in Xor mode don't get drawn in color.
Checking "Bouncier lines" makes the endpoint-box bounces more lively.
Checking "Driftier lines" makes the box-monitor bounces more lively.
Checking "Twistier lines" biases the bouncing so that one endpoint is more likely to bounce horizontally and the other is more likely to bounce vertically, on average causing more twisting.
Checking "Jumpier lines" calcuates endpoint velocities relative to the wandering box - as if it were the screen that were wandering over the box rather than the box wandering over the screen.
I've tried to make Roaming Lines the best "Roaming Lines" type screensaver avaliable. If you like it, send me a postcard from your hometown, and if you think it could be better, send me a postcard telling me why, and I'll do my best to fix it.
David Bau
777 South Avenue
Weston, MA 02193
[bau@husc9.harvard.edu] for email.
Roaming Lines is free, and may not be sold by itself or as part of any package. Electronic bulletin boards and online services which charge only connect fees for downloading time are specifically exempted from this restriction.
