Roaming Lines is a screensaver module to be used with Berkeley Systems' wonderful After Dark package. As its name suggests, Roaming Lines puts a number of bouncing, roaming lines on the 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.
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.
When you press the "Other Options..." button in the control panel, you are presented with a dialog where you can change other characterisitics of the screensaver. Checking "Dissolve screen" makes the screensaver blank the screen by blacking out random little squares, one at a time, very quickly. 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.
