zm function

Launch interaction on a plot

Allow to zoom/navigate in any open plot. The controls should be intuitive:

• zoom in:scroll up, or right click if no scrolling weel.
• zoom out:scroll down, or Hold left + right click if no working weel.
• move:left click and move

zm(type = "navigation", rp = NULL)

Arguments

• type: the type of interaction with the plot. Possible types are:

  • sessionfor console menu
  • navigationfor mouse interaction

  Or any short names for these. By default will try to launch a "navigation" session.

• rp: plot to navigate, saved using rp<-recordPlot(). By default (NULL) will use the current device.

Returns

The recording of the final plot. Can be reploted using replayPlot(). The most useful may be to get the xlim and ylim of the final plot. That can be simply got using: par("usr") after zm() ends.

Details

By default, zm() try to open a mouse interactive session. If the current device is not interactive, will try to replot the current plot in a X11(type="Xlib") device. If it fails it will open a console menu based interactive session.

Zoom handle multiple plots on a device together. You need to navigate the last one plotted and all the other plots will be navigated according to the last one: that can be pretty amazing too if you want to explore multiple layers at the same time.

Note

This function relies on pretty low level functions in R that change quite often with new versions. New version of R can break this package but I got used to it and fix it quickly.

In case you close the device before striking q, just hit Ctrl-C on the command line.

Examples

## Not run:

# basic example
plot(rnorm(1000),rnorm(1000)) # could be any plot
zm() # navigate the plot

# use the same xlim/ylim as ended up in the zoom session
xylim<-par("usr") # xmin,xmax,ymin,ymax of the final version of the plot
dev.off()
plot(rnorm(1000),rnorm(1000),xlim=xylim[1:2],ylim=xylim[3:4])

# navigate two layers of data at the same time
par(mfrow=c(1,2))
plot(1,type="n",xlim=c(-3,3),ylim=c(-3,3),main="First Track")
polygon(c(-1,1,1,-1)*2,c(-1,-1,1,1)*2,col="blue")
lines(rnorm(100),rnorm(100))
plot(1,type="n",xlim=c(-3,3),ylim=c(-3,3),main="Second Track")
polygon(c(-1,1,1,-1)*2,c(-1,-1,1,1)*2,col="green")
lines(rnorm(100),rnorm(100))
zm() # it flickers quite a bit as it needs to replot everything every time...

# one might want to use the older interface
# if attached to cairo under linux or MacOS
# it is also sometimes helpful to just define a square you want to zoom on
zm(type="s")
## End(Not run)

Author(s)

Corentin M. Barbu