Thanks for your reply, Problem solved! I am now deleting all '_patches'-data beyond my viewing window's time frame which is set to 60 seconds. I call: if len(ax._patches) > (60*10): del ax._patches[:10] I have noticed that there are 10 entries made to the 'patches'-data for every bargraph I add. Can you explain this - and/or possibly direct me to a page to read up more about "_patches". Thanks for everything Leon On 2004年5月25日 10:29:41 -0500, John Hunter <jdh...@ac...> wrote: >>>>>> "Leon" == Leon Brits <leo...@ne...> writes: > > Leon> Does this help? Should I tell the axes to "not remember" > Leon> the out-of-view data? > > Yes, this appears to be your problem. Normally, I would adivse you to > update the data of your bar elements (patches.Rectangle instances). > This would avoid the overhead of creating all the extra objects. But > for stacked bar graphs this may be more hassle than it's worth. > > But you definitely do need to clear the old instances before adding > the new ones. There are two ways to do this > > ax.cla() # clear all the axes elements > > This might introduce flicker in to your graph so you'll have to test > it. A hack is to simply clear all the patch instances from the axes. > If you are not using other patch building plot commands (eg hist, > scatter, bar) this should work fine and be the fastest solution > > ax._patches = [] > > It might be worthwhile to add a more limited clear function to the > axes. cla clears everything, but in some cases (like this one) you > might just want clear the lines, or the patches, or the text. > > If you are following matplotlib-users, I just did some profiling of > animated graphs and found that text operations were eating up about > 50% of the CPU time on animated graphs. The good news is that the > vast majority of this time can be reclaimed with some fairly easy > optimizations. > > JDH