For some reason, page 2 of this PDF document takes ages to render, while all other pages work fine.
Closed after releasing 1.8.3
Merged into 1.8-branch in revision 1542748
The radial shading is the show stopper here. I optimized the calculation of function/shading values (axial and radial shading) to speed up the rendering. I added my changes in revision 1538191. Page 2 is still the slowest one but faster than before.
Thanks for the report!
Page number 2 is the slow one.