1. 0135
2. Windows XP
3. Any example under Examples\Libraries\PDF Export:

/**
* Mouse Press.
*
* Saves one PDF of the contents of the display window
* each time the mouse is pressed.
*/


import processing.pdf.*;

boolean saveOneFrame = false;

void setup() {
size(600, 600);
frameRate(24);
}

void draw() {
if(saveOneFrame == true) {
beginRecord(PDF, "Line.pdf");
}

background(255);
stroke(0, 20);
strokeWeight(20.0);
line(mouseX, 0, width-mouseY, height);

if(saveOneFrame == true) {
endRecord();
saveOneFrame = false;
}
}

void mousePressed() {
saveOneFrame = true;
}


4. The PDF export library doesn't not properly render graphics to the screen, making
any PDF capture of an interactive work impossible. I've tested on multiple computers
and all exhibit this behavior.

that example works fine for me, though you seem to be alluding to problems
in your own code, not in the example. is that the case?

edit]
PDF Export MousePress example screenshot 1

Screen shot showing the example while running (no line)

(From update of edit])
screenshot showing the MousePress pdf library while running (no line)

edit]
PDF Export MousePress example screenshot 2

screen shot showing the resulting pdf (faint line)

edit]
code with pdf export bug

this is the file i'm working on... it draws as designed when import
processing.pdf.*; is commented out (3.jpg), otherwise it draws incorrectly
(4.jpg)

that's not a bug. beginRecord() does just that--it begins recording all
graphics commands to a file. there's no way for it to know what stroke and
fill you've set back in setup(). as soon as you call beginRecord(), you're
dealing with a fresh drawing surface.

we may change this someday, see bug #346, but it introduces a lot of
complexity so we have not so far.