On 10/6/07, Søren Hauberg <address@hidden> wrote:
Shai Ayal skrev:
This is basically what is used by all OpenGL systems -- octplot &
jhandles included. It is a highly non-trivial taks to "render" 3D
OpenGL in postscript, and gl2ps is the best tool to do it. All the
problems actually stem from OpenGL, not the conversion to ps. As I
noted elsewhere, using OpenGL & gl2ps will give OK results, but not
100% professional -- e.g. lines will not always join nicely, and some
numerical glitches may be noticeable -- OpenGL uses no more than
floats to do all it's calculations. This is most noticeable in 2D
plots, less so in 3D plots.
However, all that being said, the ps results are quite nice, and are
truely resolution independant vector graphics.
I'm curious: do you believe that gl2ps provides good enough output to be
used as the only way to create postscript output in Octave in some
distant future? Or can it only be a temporary solution for the GL based
projects?
I think the problem is OpenGL. It is not a high quality hardcopy
producing library -- it is a high speed screen 3D scene renderer. As
an example -- OpenGL has no concept of how to join lines -- take a
look at:
http://cairographics.org/samples/fill_and_stroke2/
In OpenGL, all the places where lines join at not 90 deg, it would
look bad (and probably even at places with 90 deg joins). A "real" 2D
hardcopy oriented library has facilities for this :
http://cairographics.org/samples/set_line_join/.
However as much as I like cairo (could you guess?) it has no support
whatsoever for 3D, and the people want 3D, and you must give the
people what they want ...
I am far from a graphics expert, but I am not aware of any 3D library
which does this (actually they are all based on OpenGL)