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Object Graphics slow??



In recent discussion about object graphics vs direct graphics it has been
generally accepted that the object graphics system is slower. In an idle
moment (ha!) I was inspired to run a couple of quick tests to see just how
much slower. Here are the results:

* Plot a line graph with 1000000 (that's 1 million) points:

Object graphics (create and draw an IDLgrplot object): 1.45 s
Direct graphics (call 'plot'): 2.90 s

* Draw 100 byte arrays, each [256, 256], in succession as gray-scale images:

Object graphics (create, draw and destroy 100 IDLgrImage objects): 2.9 s
Direct graphics (call 'tv' 100 times): 6.2 s

These examples (and I accept that they're limited) don't bear out the
general opinion.

Tests done on Windows NT, IDL 5.3, Compaq machine with Pentium II 400 MHz
CPU, 256 MB RAM.

---
Mark Hadfield
m.hadfield@niwa.cri.nz  http://katipo.niwa.cri.nz/~hadfield/
National Institute for Water and Atmospheric Research
PO Box 14-901, Wellington, New Zealand