srt --- slope text with function?
On 2/4/2006 3:50 PM, ivo welch wrote:
[resent, plus small addition; I do not understand why gmail sent a weird charset.] Dear R wizards: I would love to write a general function that matches the slope of a plotted line in an xy-plot at a particular x,y location. something like x<- (1:10)^2; y<- 40:50; plot( x,y, type="l", xlim=c(0,90) ) srt.at5 = text.at.current.plot.with.slope( x, y, 5); text( x[5],y[5], pos=3, srt=srt.at.5); to do this, I first need to compute the function slope around x[5], which is an easy task. alas, the harder task is that I need to scale this by the plot aspect ratio and the axes. How can a function read this from the current plot?
I haven't done this, but you can presumably work it out from the conversions implied by the "fig", "fin", "plt", and/or "usr" values.
(Has someone written such a function, perhaps more embellished, to save me the debugging effort?) Or, is there an alternative to srt, which slopes the text relative to the existing scale? *** come to think of it, what I would really like is the ability of text to 'snake' itself along the line itself. I doubt that this is easily possible, but I just wanted to ask.
Using strsplit and strwidth you should be able to do it, but it will probably look quite ugly. Duncan Murdoch