Re: [Plplot-general] Fast/slow plotting

[Maurice L. <mj...@br...>]

On Thursday, January 17, 2008 at 21:40:20 (+0100) Torquil Macdonald S=F8=
rensen writes:
 > Hello,
 >=20
 > I have a C++ program that simulates the movements of polygons. It ru=
ns a=20
 > plotting function e.g. every 100 iterations of the simulation. Why i=
s it that=20
 > when I use PLPLOT there is lots of flickering, but with PGPLOT it lo=
oks great=20
 > without any flickering? Is PGPLOT much faster than PLPLOT or am I do=
ing=20
 > something wrong? With plplot it is too much flickering to be able to=
 watch=20
 > the polygons move around. I have tried setting the xwin device optio=
ns=20
 > nobuffering and sync, but there was no difference.
 >=20
 > Here is a description of the code:
 > ...

The xwin device with double buffering set (-db from the command line) s=
hould
do the trick.  Do not use sync, that slows the processing of commands b=
y the X
server way down.  Another thing to keep in mind is that the axes should=
 remain
fixed throughout the run, else there will be flickering caused by the t=
icks &
axis labels moving back & forth.

This technique works extremely well on sufficiently simple plots, and n=
ot too
badly on plots of medium complexity either.  To see it in action, try z=
ooming
& panning using the TK driver / plframe extended TK.

 > void new_page() {
 > =09plclear();
 > =09plbox("bcinst", 0, 0, "bcinst", 0, 0);
 > }
 >=20
 > void plot() {
 > =09new_page();
 > =09{..calculate plot quantitie here...}
 > =09{... some plline() functions...}
 > }
 > =09
 > int main() {
 > =09plsdev("xwin");
 > =09plinit();
 > =09plenv(xmin, xmax, ymin, ymax, 1, -2);
 >=20
 > =09for(int i =3D 0; i !=3D i_max; ++i) {
 > =09=09{...simulation_code here...}
 > =09=09if(i % 100 =3D=3D 0) plot();
 > =09}
 >=20
 > =09plend();
 > =09return(0);
 > }
 >=20
 > Best regards,
 > Torquil S=F8rensen

--=20
Maurice LeBrun