On Thu, Apr 23, 2009 at 2:32 PM, Elan Pavlov <epav...@gmail.com> wrote: > Hi Jae-Joon, > Thanks a ton! The problem is actually not the frequency of changes. > The current method uses draw_artist on each update. However, the time > for draw_artist is linear in the *number* of points so for graphs with > a large amount of data it is extremely inefficient. Your patch means > that update time is linear in the amount of data *updated* and not in > the total amount of data. > As for the ticks you have a point. In my application I actually want > ticks to be shifted (as time goes on) so indeed this is what I want.
I was more concerned about yticks (when images are shifted in x-direction). Anyhow, it should be not that difficult to handle this. > In general ticks that are shifted out can be redrawn using set_data > methods which are efficient since a tick can be defined as it's > endpoints. Basically when first calling plot() I set all of the tick > locators to Null and then just add ticks as a line (with two points) > based on the desired spacing. Changing a tick location (or if desired > redrawing it in the same location) is basically a call to > set_(x|y)data and then draw_artist for a line with two points (or a > line collection will *slightly* improve performance if needed). > Anyway, thanks again. I'll play around with it and let you know what I > run into. Yes, please. If you find this useful, I'll try to push this into the trunk. Regards, -JJ > > Elan > --- > I can no other answer make but thanks, > And thanks, and ever thanks. > -- William Shakespeare > > On Thu, Apr 23, 2009 at 1:21 PM, Jae-Joon Lee <lee.j.j...@gmail.com> wrote: >> On Mon, Apr 20, 2009 at 4:34 PM, Elan Pavlov <e...@mit.edu> wrote: >>> Hi, >>> >>> I'm trying to use matplotlib for animating data as it is received from an >>> online source (online in the algorithmic sense not internet:). I'd like >>> the graph plot to be updated with high frequency since the data changes >>> rapidly. I've used the BufferRegion with copy_from_bbox / restore_region >>> and it speeds up the plotting considerably but alas it's still not good >>> enough (with a large number of graphs and a large number of data points in >>> each graph). >>> >> >> Well, if you need your plot updated with very high frequency, MPL may >> not be your tool of choice. >> Anyhow, my first recommendation is not to update the plot frequently. >> I mean, do you have to update the plot for every changes? Can you >> update it every 10th change, for example? >> >>> What I'd like to do is to utilize the fact that the animation is updated >>> in a predictable fashion (i.e., scrolling off the screen to the left as >>> new data arrives) in order to speed up the animation. The idea would be to >>> copy the right 99% of the graph (or some other fraction) via some kind of >>> function similar to copy_from_bbox, move it 1% to the left and then plot >>> the new 1% of the data. The problem is that as far as I can tell the >>> copy_from_bbox/restore_region does not actually allow changing the area in >>> which it is restored. I've mucked around in the source files a bit but to >>> no avail. >>> >>> My question is then: >>> 1. Is there some other way to copy everything enclosed in a Bbox? or >>> 2. Is there some way to modify the region in which data reappears when >>> using restore_region? >>> 3. Perhaps I'm missing something? >>> >>> I'm sure someone else has done this since it seems pretty natural and >>> useful for a variety of applications. >> >> I'm attaching a patch that might do what you want to do. >> It implements a "restore_bbox2" method which restores a subset of the >> saved background at a specified position. >> A small example is also attached (it is based on the gtk backend). >> >> I, personally, am not sure if this kind of feature is useful. If you >> shift part of your figure, you have to be careful not to mess up with >> the coordinate system. And also be careful about what to be shifted >> and what to be not (e.g., ticks). >> >> If others find this useful, I'll commit this to the trunk with some >> api improvement. >> >> Regards, >> >> -JJ >> >> >>> >>> Elan >>> ---- >>> "If stupidity got us into this mess, why can't it get us out?" >>> - Will Rogers >>> >>> ------------------------------------------------------------------------------ >>> Stay on top of everything new and different, both inside and >>> around Java (TM) technology - register by April 22, and save >>> $200 on the JavaOne (SM) conference, June 2-5, 2009, San Francisco. >>> 300 plus technical and hands-on sessions. 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