[R] help simplifying complex graphic arguments to a function

[baptiste auguie]

I'm facing a similar challenge with a grid.table function (see example
below). I envisaged two routes,

1- rather than assigning a list of properties for each cell, I would
define a matrix for each property. For instance, the default could be,

fill = matrix("grey90", nrow(values), ncol(values)) # or an array if
more than 2D
col = matrix("red", nrow(values), ncol(values))
col.text = matrix("black", nrow(values), ncol(values))

The drawing of each cell would look like,

for( ii in 1:nrow){
 for (jj in 1:ncol){
  grid.rect(gp=gpar(fill = fill[ii, jj], col = col[ii, jj]))
  grid.text(values[ii, jj], gp = gpar(col= col.text[ii, jj]))
  # or whatever grid function you need
   }
}

2- Create the table with default values, but give a name to each grob
and allow for subsequent editing of individual gpar() properties.
(as suggested in sec. 7.3.10 "avoiding argument explosion" of Paul
Murrell's R graphics book)

Perhaps a structure like a gTree can help (in my case I wanted the
table header to have different settings than the rest of the table).

Best,

baptiste


source("http://gridextra.googlecode.com/svn/trunk/R/tableGrob.r")

 tc  = textConnection("
      carat   VeryLongWordIndeed color clarity depth
 14513  1.35 Ideal     J     VS2  61.4
 28685  0.30  Good     G    VVS1  64.0
 50368  0.75 Ideal     F     SI2  59.2")
 d = read.table(tc,head=T)
 close(tc)

grid.newpage()
g = grid.table(d)

grid.ls(g) # not much of a clue which is which... let's edit a random
one (numbers probably session-dependent)
grid.edit("GRID.tableGrob.556::table.header.left::GRID.cellGrob.718::GRID.rect.717",
gp=gpar(fill="red"))



2009/8/17 Michael Friendly <friendly at yorku.ca>:
> I'm working on a package to produce graphic displays of 2- and 3-way tables
> and need some help/advice on how to simplify the specification of a complex
> argument that gives the drawing details for each cell of the table.
> Prototypes of two functions, 'tableplot' and 'cellgram' are given below.
>
> The essential idea is that for a given table ('values'), the cells can be
> be of different 'types' (integers: 1, 2, ..., max(types)).  An argument
> 'patterns' is a list of max(types) lists, where patterns[[k]] is presently
> a list of 10 graphic parameters specifying shapes, colors, fill, background
> color,
> etc. that are passed as arguments to the cellgram function.
>
> The difficulty is that it's too hard to remember the order and meaning
> of the cellgram arguments to be passed in the patterns argument to
> tableplot,
> and often quite a few of these will take their default values, but-- as
> presently written-- all must be specified.
>
> The actual implementation of these functions use grid graphics, and I know
> from other grid-based packages that use named specifications like
>
> gp = gpar(shape=1, shape.col="black", shape.lty=2, ...)
>
> are commonly used, but I'm unable to see how to re-write these functions to
> take advantage of that form.  To be specific, I need to re-write cellgram
> to take two arguments
>
> cellgram(cell.values, cell.pattern)
>
> and then be able to extract the current arguments from cell.pattern within
> this function.
>
>
> tableplot <- function(
>
>   values,               # Matrix of values to plot; can be a matrix, or an
> array of 3 dimensions.
>   types,          # Matrix of pattern designations (i.e., what pattern for
> each cell).
> #    patterns,             # List of lists; each list specifies one pattern.
>   patterns = list(list(0, "black", 1, "white", "white", 0, 0.5, "grey80",
> "no", 1)),
>   ...){
>
> #
>   #---Draw cellgrams.
>
>   for (i in 1:dim(values)[1]){
>       for (j in 1:dim(values)[2]){
>
>           pattern = patterns[[types[i,j]]]
>           cellgram(cell       = values[i,j,],
>                  shape      = pattern[[1]],
>                  shape.col = pattern[[2]],
>                  shape.lty = pattern[[3]],
>                  cell.fill = pattern[[4]],
>                  back.fill = pattern[[5]],
>                  label     = pattern[[6]],
>                  label.size= pattern[[7]],
>                  ref.col     = pattern[[8]],
>                  ref.grid     = pattern[[9]],
>                  scale.max = pattern[[10]]
>                  )
>           }
>       }
>
> }
>
> cellgram = function(
>
>   #-- Arguments that may be vectorized:
>
>   cell,                   #-- cell value(s)
>   shape=0,               #-- shape of cell value(s); 0=circle, 1=diamond,
> 2=square, 3=cross
>   shape.col="black", #-- color of shape(s), outline only
>   shape.lty=1,         #-- line type used for shape(s)
>
>   #-- Arguments that can not be vectorized:
>
>   scale.max=1,     shape.lwd=1,       #-- line width of shape(s)
>   cell.fill="white", #-- inside color of smallest shape in a cell
>   back.fill="white", #-- background color of cell
>   label=0,           #-- how many cell values will be printed; max is 4
>   label.size=0.7,    #-- size of text labels
>   ref.col="grey80",  #-- color for ref lines
>   ref.grid=TRUE,     #-- to draw ref lines or not
>   neg.col="white",   #-- fill color for negative cell value
>   frame.col="black", #-- color of frame around cell
>   frame.lwd="0.5"    #-- line width of frame around cell
>   t.col="black",     #-- color of cell labels  [[ should be: label.col]]
>   )
> {
> # ...
> }
>
>
> --
> Michael Friendly     Email: friendly AT yorku DOT ca Professor, Psychology
> Dept.
> York University      Voice: 416 736-5115 x66249 Fax: 416 736-5814
> 4700 Keele Street    http://www.math.yorku.ca/SCS/friendly.html
> Toronto, ONT  M3J 1P3 CANADA
>
> ______________________________________________
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> and provide commented, minimal, self-contained, reproducible code.
>



-- 
_____________________________

Baptiste Auguié

School of Physics
University of Exeter
Stocker Road,
Exeter, Devon,
EX4 4QL, UK

http://newton.ex.ac.uk/research/emag