R quantmod chartSeries newTA chob - modify legend and axis (primary and secundary) - r

Question

This is an advanced question.
I use my own layout for the chartSeries quantmod function, and I can even create my own newTA. Everything works fine. But ...
What I want to do but I can't:
a) Manipulate the legend of each of the 3 charts:
- move to other corner, (from "topleft" to "topright")
- change the content
- remove completely if needed ...
b) My indicator generates 2 legends:
value1
value2
same as above ... how could I modify them? how could I delete them?
c) control position and range of yaxis (place it on the left / right
or even remove them
same when there is a secundary axis on the graph
d) Modify main legend (the one in the top right
where is written the range of dates
A working sample code:
# Load Library
library(quantmod)
# Get Data
getSymbols("SPY", src="yahoo", from = "2010-01-01")
# Create my indicator (30 values)
value1 <- rnorm(30, mean = 50, sd = 25)
value2 <- rnorm(30, mean = 50, sd = 25)
# merge with the first 30 rows of SPY
dataset <- merge(first(SPY, n = 30),
value1,
value2)
# **** data has now 8 columns:
# - Open
# - High
# - Low
# - Close
# - Volume
# - Adjusted
# - a (my indicator value 1)
# - b (my indicator value 2)
#
# create my TA function - This could also be achieve using the preFUN option of newTA
myTAfun <- function(a){
# input: a: function will receive whole dataset
a[,7:8] # just return my indicator values
}
# create my indicator to add to chartSeries
newMyTA <- newTA(FUN = myTAfun, # chartSeries will pass whole dataset,
# I just want to process the last 2 columns
lty = c("solid", "dotted"),
legend.name = "My_TA",
col = c("red", "blue")
)
# define my layout
layout(matrix(c(1, 2, 3), 3, 1),
heights = c(2.5, 1, 1.5)
)
# create the chart
chartSeries(dataset,
type = "candlesticks",
main = "",
show.grid = FALSE,
name = "My_Indicator_Name",
layout = NULL, # bypass internal layout
up.col = "blue",
dn.col = "red",
TA = c(newMyTA(),
addVo()
),
plot = TRUE,
theme = chartTheme("wsj")
)
I have tried using legend command, and also the option legend.name (with very limited control of the output).
I have had a look at the chob object returned by chartSeries, but I can't figure out what to do next ...
Image below:

Answer 1

After some time learning a little bit more about R internals, S3 and S4 objects, and quantmod package, I've come up with the solution. It can be used to change anything in the graph.
A) If the legend belongs to a secundary indicator window:
Do not print the chartSeries (type option plot = FALSE) and get the returned "chob" object.
In one of the slots of the "chob" object there is a "chobTA" object with 2 params related to legend. Set them to NULL.
Finally, call the hidden function chartSeries.chob
In my case:
#get the chob object
my.chob <- chartSeries(dataset,
type = "candlesticks",
main = "",
show.grid = FALSE,
name = "My_Indicator_Name",
layout = NULL, # bypass internal layout
up.col = "blue",
dn.col = "red",
TA = c(newMyTA(),
addVo()
),
plot = FALSE, # do not plot, just get the chob
#plot = TRUE,
theme = chartTheme("wsj")
)
#if the legend is in a secundary window, and represents
#an indicator created with newTA(), this will work:
my.chob#passed.args$TA[[1]]#params$legend <- NULL
my.chob#passed.args$TA[[1]]#params$legend.name <- NULL
quantmod:::chartSeries.chob(my.chob)
B) In any other case, it is possible to modify "chartSeries.chob", "chartTA", "chartBBands", etc and then call chartSeries.chob
In my case:
fixInNamespace("chartSeries.chob", ns = "quantmod")
quantmod:::chartSeries.chob(my.chob)
It is just enough with adding "#" at the beginning of the lines related to legend().
That's it.