On Wednesday 30 March 2005 10:39 pm, John Hunter wrote:
> JDH> - implement draw_markers and draw_lines with the new API
> JDH> (transform is done in backend).
[..snip..]
I made a first (and second) attempt at implementing draw_markers and
draw_lines in the postscript backend. The changes are in CVS, although I left
draw_markers masked as _draw_markers, it needs to be unmasked if you want to
try it out.
I found some places for speed/memory/ps-filesize improvements. With
draw_markers masked, the script below took 2.43 seconds to generate and write
the 1.5MB eps file. With draw_markers unmasked, it took 0.69 seconds to make
a 350KB eps file.
Some comments:
1) Circles are being drawn with draw_markers, but agg.path_storage has no
curve information in it? Circles are faithfully reproduced in ps output, but
it takes 50 line segments to draw each circle in plot(arange(10000),'-o').
2) I think each tickmark is listed in agg.path_storage twice, and therefore
gets rendered twice in PS.
3) I expected marker paths to be terminated with the agg.path_cmd_end_poly
code. This is not the case. What is the purpose of path_cmd_end_poly?
4) I am getting an unrecognized agg.path_commands_e code. They should be one
of 0,1,2,3,4,6,0x0F, and I am getting a value of 70. ?? I just ignore it and
PS seems to render fine.
5) Im not doing anything with vec6 = transform.as_vec6_val(). I'm not sure
what it is used for.
6) draw_lines is getting a long pathlist from agg. Rather than draw a straight
line between two points, it is doing something like
50.106 249.850 moveto
53.826 249.850 lineto
57.546 249.850 lineto
61.266 249.850 lineto
and thats just for the line in the legend! The straight line in the actual
plot has many, many intermediate points.
Feedback appreciated!
from pylab import *
from time import clock
figure(1)
plot(arange(10000),'-s')
l=legend(('1e4 markers',))
d = clock()
savefig('temp.eps')
print clock()-d
--
Darren