rect on top of quantmod series is off when changing window size

Question

i'm trying to draw a rectangle on top of a chart series drawn with quantmod.

> s<-get(getSymbols('phmd'))["2012:"]
> d<-findSupport(s,p=5,threshold=1)
> d
       low     high cnt        std
1 14.79000 14.85292   2 0.04448880
2 13.27222 13.31500   2 0.03024846
3 13.09000 13.15000   2 0.04242641
4 14.12000 14.20583   2 0.06069333
5 12.30222 12.38421   2 0.05797449
6 11.38269 11.43200   2 0.03486580
> chartSeries(s)
> u <- par("usr")
> rect(u[1],d[,'low'],u[2],d[,'high'],col=rgb(1,0,0,alpha=0.5),border=0)

the rectangles being drawn are way off when changing the window size. why is that and how can i overcome this ? please assist, Thanks.

Answer 1

I don't know very well quantmod. But I think you must add_XXX functions which add information to the plot object (chob) and re-draw it. see addLines for example.

That's said, when I use chart_Series the experimental function, I don't have a problem when I re-size the window.