A strange solid band appears when drawing a diagonal line from the upper
left corner to the lower right corner. The thickness of the line has to be
larger than 5, and smooth enabled.
Processing version is v0125. Perhaps a Java2D bug? At least, when using
the opengl renderer, the bug doesn't show up.

In any case, here is the "offending" code:

[code]
size(200, 200);
background(0);

smooth();

strokeWeight(5);
stroke(255);
line(0, 0, 200, 200);
[/code]

can you attach a screenshot (just use saveFrame() on that sketch)? what
version of java are you using?

haven't heard back so i'll close the bug. my assumption is that this is a
java2d bug, perhaps with the opengl rendering pipeline for java2d in later
releases.