updating only changes to a graph/image?

[John_Nowlan]

I need to build a few 'dashboardy' web pages with pretty pictures/graphs that update periodically.

I found this cookbook recipe http://wiki.pylonshq.com/display/pylonscookbook/Adding+graphical+output, but what I am wondering is, has anyone done something like this where only diffs are updated, i.e. if the graph displays a 1 hour time period that is updated every minute, is there a way to do a diff on an image and just update the changed part (the 1st and last minute)?

Sort of a diff on a binary (image) then updating/streaming only the new bits (but whole image gets replaced so is it achieving anything?).

I realize I am explaining this poorly, partly because I don't know where to begin (never used PIL, not even sure it is right tool for job), but if anyone has any pointers/guidance would like to hear!

Performance is not a problem so whole image updating will almost definitely be the way to go to get something done, but this is something I've often wondered about and figured as a Friday question it would be worth throwing out there.

I could generate 60 1 minute images then drop last and shift over, not sure if that would work & seems hacky. Other ideas or just regen the whole image each time?

[Steve Piercy]

On Jul 8, 8:23 am, John_Nowlan <john_now...@carleton.ca> wrote:
> I need to build a few 'dashboardy' web pages with pretty pictures/graphs that update periodically.
>

> I found this cookbook recipehttp://wiki.pylonshq.com/display/pylonscookbook/Adding+graphical+output, but what I am wondering is, has anyone done something like this where only diffs are updated, i.e. if the graph displays a 1 hour time period that is updated every minute, is there a way to do a diff on an image and just update the changed part (the 1st and last minute)?

Other ideas:
Try charts in HTML5 <canvas>.
http://mbostock.github.com/d3/
http://vis.stanford.edu/protovis/
http://code.google.com/apis/chart/
http://raphaeljs.com/
http://www.liquidx.net/plotkit/
http://code.google.com/p/flot/
http://www.filamentgroup.com/lab/update_to_jquery_visualize_accessible_charts_with_html5_from_designing_with/

--steve

[Bruce Wade]

http://dojotoolkit.org/documentation/tutorials/1.6/charting/ + HTML5 Canvas + WebGL for 3D

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Regards,
Bruce Wade
http://ca.linkedin.com/in/brucelwade
http://www.wadecybertech.com
http://www.warplydesigned.com
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[John_Nowlan]

Thanks for the pointers!