little arrows on quantmod charts
Hi Mark, The issue isn't the R code, it is the device (and the underlying R graphics engine). This won't be readily doable, at least not in the true sense. quantmod wasn't meant to replace RT charting, it was (like R) designed to analyze data in R _as if_ you had it in a typical charting platform. The new use of a custom internal 'layout' will allow for updates without redrawing the screen, but that has limits too. Since R uses a paint approach (overlying), you can get some strange artifacts. When R gets a better device, I will likely rewrite to take advantage of it. I am not inclined to simply replicate what is available elsewhere though (much to the surprise of some... :) ) Replotting everything every minute or so would probably be tolerable of course... but tick by tick flashing/redraw would make your office into a 1970's disco. Best, Jeff
On Fri, Oct 23, 2009 at 12:39 PM, Mark Breman <breman.mark at gmail.com> wrote:
Hi Jeff, I was thinking about if it would be possible to chart streaming price data with the new engine. For instance candles that get updated tick by tick as prices come in. I know from other development tools and charting libraries that it is very important for speed to have a renderer that does not render the entire chart, but only the areas that changed. Would something like that be possible with the new engine? Regards, -Mark- 2009/10/23 Jeff Ryan <jeff.a.ryan at gmail.com>
While this isn't yet in the released version of quantmod, the entire graphical engine underlying charting via quantmod is being rewritten. The net effect is that it will now render as one graphic, so enabling the use of charts inside of standard mfcol/layout plot regions, as well as a more robust mechanism regarding how additions get appended to charts. ?Things are much faster and quite a bit more pleasing to the eye now. Another facet of the new engine is that it will allow for base graphics to be more easily incorporated _into_ the charts. ?I will be adding wrappers to make the process easy, but it will be possible even without them. ?Currently this is a challenge in the current system (even for me -- having a decent knowledge of what I wrote.) I will also add a mechanism to add more common types of additions, like signals. ?Requests for additional features would be much appreciated!! Brave souls are invited to contact me for access and a quick example or two before the release. ?All code is on R-forge as well. Best, Jeff On Fri, Oct 23, 2009 at 12:21 AM, Wind <windspeedo99 at gmail.com> wrote:
Stock charts in quantmod are as good as other commercial softwares'. Yet I wonder how to add little arrows to the barChart. ? Something as http://www.trendprognosis.com/wp-content/uploads/2009/05/VLE0612.gif Sometimes little arrows are better than shaded area on the charts. ?Several kinds of arrows for buy, sell, stop, warning would be enough. Thanks. Wind ? ? ? ?[[alternative HTML version deleted]]
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-- Jeffrey Ryan jeffrey.ryan at insightalgo.com ia: insight algorithmics www.insightalgo.com
_______________________________________________ R-SIG-Finance at stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-sig-finance -- Subscriber-posting only. -- If you want to post, subscribe first.
Jeffrey Ryan jeffrey.ryan at insightalgo.com ia: insight algorithmics www.insightalgo.com