| draw.leg {IDPmisc} | R Documentation |
Produces (and possibly draws) a Grid frame grob which is a legend that
can be placed in other Grid plots. draw.leg is a
slightly enhanced version of draw.key in
package lattice V 0.12-3.
draw.leg(key, draw=FALSE, vp=NULL)
key |
A list determining the key. See details below and the
documentation for xyplot.
|
draw |
logical, whether the grob is to be drawn. |
vp |
viewport |
Three new components are added to the list key of the original code
in package lattice V 0.12-3: between.rows,
between.title, adj.title. They allow to format the
legend in a more flexible way. To ease the use of draw.leg, the
full description of draw.key and the here
interesting part of xyplot are also included:
The key essentially consists of a number of columns, possibly
divided into blocks, each containing some rows. The contents of the
key are determined by (possibly repeated) components named
``rectangles'', ``lines'', ``points'' or ``text''. Each of these
must be lists with relevant graphical parameters (see later)
controlling their appearance. The key list itself can contain
graphical parameters, these would be used if relevant graphical
components are omitted from the other components.
The length (number of rows) of each such column (except ``text''s)
is taken to be the largest of the lengths of the graphical
components, including the ones specified outside (see the entry for
rep below for details on this). The ``text'' component has to
have a character or expression vector as its first component, and
the length of this vector determines the number of rows.
The graphical components that can be included in key (and
also in the components named ``text'', ``lines'', ``points'' and
``rectangles'' as appropriate) are:
cex=1
col="black"
lty=1
lwd=1
font=1
fontface
fontfamily
pch=8
adj=0
type="l"
size=5
angle=0
density=-1
adj, angle and density are currently
unimplemented. size determines the width of columns of
rectangles and lines in character widths. type is relevant
for lines; "l" denotes a line, "p" denotes a point,
and "b" and "o" both denote both together.
Other possible components of key are:
betweentitlerepTRUE. By default, it's assumed that
all columns in the key (except the ``text''s) will have the same
number of rows, and all components are replicated to be as long
as the longest. This can be suppressed by specifying
rep=FALSE, in which case the length of each column will
be determined by components of that column alone.
cex.titlebackgroundborderborder is
TRUE, and no border is drawn if it is FALSE (the
default)
transparent=FALSEcolumnsbetween.columnsbetween.
between.rowsbetween.titleadj.titleadj.title
= 0 adjusts the title to the left, adj.title
= 1 adjusts the title to the right and adj.title
= 0.5 (=default) centers the title.
dividetype is
"b" or "o" in lines.
A Grid frame object (that inherits from ``grob'')
Deepayan Sarkar, modified by Rene Locher
grid.newpage()
key <- draw.leg(key = list(rectangles = list(col=1:3,
size = 2,
lwd = 0.5),
text=list(LETTERS[1:3]),
cex=1.2,
between=2,
between.rows=0.5,
between.title=0.7,
title = "component",
cex.title = 1.4,
transparent = TRUE))
vp.key <- viewport(x = convertX(unit(1,"npc")-unit(1,"cm"),"cm"),
y = convertY(unit(1,"cm"),"cm"),
width=grobWidth(key),
height=grobHeight(key),
just=c("right","bottom"))
pushViewport(vp.key)
grid.draw(key)
popViewport()
##----------------------------------------
## another example, where the title is left adjusted
key <- draw.leg(key = list(rectangles = list(col=1:3,
size = 4,
lwd = 0.5),
text=list(letters[1:3]),
lines=list(col=1:3),
cex=2,
between=2,
between.rows=0.5,
between.title=0.7,
title = "component",
adj.title = 0,
cex.title = 2.4,
transparent = TRUE))
vp.key <- viewport(x = 0,
y = unit(1,"cm"),
width=grobWidth(key),
height=grobHeight(key),
just=c("left","bottom"))
grid.newpage()
pushViewport(vp.key)
grid.draw(key)
popViewport()