The grid package
What is the `grid` package?
Author: Paul Murrell Part of the 14 base packages.
Grid graphics provides an alternative to the standard R graphics. The user is able to define arbitrary rectangular regions (called viewports) on the graphics device and define a number of coordinate systems for each region. Drawing can be specified to occur in any viewport using any of the available coordinate systems.
What makes `grid` great?
- Perfect control over the over output
- Your imagination sets the limit
- Code professional info-graphics
Basics
Everything is arranged around viewports. A viewport has:
- x/y position
- width/height
- encapsulation
library(grid)
grid.newpage()
pushViewport(viewport(x=.6, y=.5, width=.6, height=.6))
grid.rect(gp = gpar(fill="steelblue"))
grid.rect(width=unit(2, "cm"), height=unit(2, "cm"),
x=0, y=0, just=c(0,0),
gp = gpar(fill="lightyellow"))
grid.rect(width=unit(2, "cm"), height=unit(2, "cm"),
x=1, y=1, just=c(1,1),
gp = gpar(fill="yellow"))
upViewport()
Viewports 4 sub-elements - why?
Adding text to boxes without viewports:
grid.newpage()
pushViewport(viewport(x=.5, y=.5, width=.9, height=.9))
grid.rect(gp = gpar(fill="steelblue"))
grid.rect(width=unit(2, "cm"), height=unit(2, "cm"),
x=0, y=0, just=c(0,0),
gp = gpar(fill="lightyellow"))
grid.text("BL",
x=unit(1, "cm"),
y=unit(1, "cm"))
grid.rect(width=unit(2, "cm"), height=unit(2, "cm"),
x=1, y=1, just=c(1,1),
gp = gpar(fill="yellow"))
grid.text("TR",
x=unit(1, "npc") - unit(1, "cm"),
y=unit(1, "npc") - unit(1, "cm"))
upViewport()
What about:
- Re-sizing?
- Component isolation?
Viewports 4 sub-elements - how?
Adding text to boxes with viewports:
grid.newpage()
pushViewport(viewport(x=.5, y=.5, width=.9, height=.9))
grid.rect(gp = gpar(fill="steelblue"))
pushViewport(
viewport(x=0, y=0,
width=unit(2, "cm"), height=unit(2, "cm"),
just=c(0,0)))
grid.rect(gp = gpar(fill="lightyellow"))
grid.text("BL")
upViewport()
pushViewport(
viewport(x=1, y=1,
width=unit(2, "cm"), height=unit(2, "cm"),
just=c(1,1)))
grid.rect(gp = gpar(fill="yellow"))
grid.text("TR")
upViewport()
upViewport()
Viewports allow encapsulating
box <- function(box_label,
x, y, height, width,
just) {
pushViewport(
viewport(x=x, y=y,
width=width, height,
just=just))
grid.rect(gp = gpar(fill="lightyellow"))
grid.text(box_label)
upViewport()
}
library(grid)
grid.newpage()
pushViewport(viewport(x=.5, y=.5, width=.9, height=.9))
grid.rect(gp = gpar(fill="steelblue"))
box("BL",
x=0, y=0,
width=unit(2, "cm"), height=unit(2, "cm"),
just=c(0,0))
box("TR",
x=1, y=1,
width=unit(2, "cm"), height=unit(2, "cm"),
just=c(1,1))
upViewport()
Encapsulating side benefits
boxFancy <- function(box_label,
x, y, height, width,
just) {
pushViewport(
viewport(x=x, y=y,
width=width, height,
just=just))
grid.rect(gp = gpar(fill="lightyellow"))
grid.text(box_label,
gp=gpar(cex=3))
width = convertUnit(unit(1, "npc"), "cm")
pushViewport(viewport(x = 0, y=0, just=c(0,0),
width=.5, clip="on"))
grid.rect(gp=gpar(fill="yellow", col=NA))
grid.text(box_label,
gp=gpar(cex=3, col="red"),
vp=viewport(width = width, x=0,y=0,
just=c(0,0)))
upViewport()
grid.rect(gp = gpar(fill=NA))
upViewport()
}
library(grid)
grid.newpage()
boxFancy("Some random text",
x=0.5, y=0.5,
width=unit(.8, "npc"), height=unit(.8, "npc"),
just=c(0.5,0.5))
Core parts 4 a flowchart
library(Gmisc)
grid.newpage()
pushViewport(vp = viewport(gp = gpar(cex = 2)))
box <- list(
boxGrob("This box autosizes to the\ntext within",
y=unit(.95, "npc"), bjust="top"),
boxPropGrob("This box can show a porportion",
label_left = "Left",
label_right = "Right",
prop=.3,
y=unit(0.05, "npc"), bjust="bottom"))
lapply(box, grid.draw)
Core parts 4 a flowchart - positions
grid.newpage()
pushViewport(vp = viewport(gp = gpar(cex = 2)))
lapply(box, grid.draw)
draw_coords <- function(box)
with(attr(box, "coords"), {
grd_circ <- function(x,y,fill)
grid.circle(x=x, y=y, gp=gpar(fill=fill),
r=unit(2, "mm"))
grd_circ(x=x, y=y, "black")
grd_circ(x=x, y=top, "yellow")
grd_circ(x=x, y=bottom, "yellow")
grd_circ(x=left, y=y, "orange")
grd_circ(x=right, y=y, "orange")
if ("left_x" %in% ls()) {
grd_circ(x=left_x, y=top, "blue")
grd_circ(x=left_x, y=bottom, "blue")
grd_circ(x=right_x, y=top, "purple")
grd_circ(x=right_x, y=bottom, "purple")
}
})
lapply(box, draw_coords)
flowchart - connect
grid.newpage()
pushViewport(
vp=viewport(gp=gpar(cex=2)))
lapply(box, grid.draw)
lapply(box, draw_coords)
connectGrob(start=box[[1]],
end=box[[2]],
type="v")
flowchart - connect to prop
grid.newpage()
pushViewport(
vp=viewport(gp=gpar(cex=2)))
lapply(box, grid.draw)
lapply(box, draw_coords)
connectGrob(start=box[[1]],
end=box[[2]],
type="v",
subelmnt="left")
connectGrob(start=box[[1]],
end=box[[2]],
type="v",
subelmnt="right")
Finally a flowchart
grid.newpage()
distance <- unit(.2, "npc")
boxs <- list()
boxs$start_pop <- boxGrob("Start pop.\nn = 145 patients", y=1, bjust="top")
boxs$included <-
boxGrob("Included n = 78 patients", bjust="top",
y=attr(boxs$start_pop, "coords")$bottom - distance)
boxs$excluded <-
boxGrob("Excluded:\n - 40 CHF\n - 7 prev. hist.\n - 20 misc.",
y=attr(boxs$start_pop, "coords")$bottom - unit(.1, "npc"),
x=1, bjust="right", just="left")
boxs$groups <-
boxPropGrob("Randomized",
label_left=sprintf("Treatment\n %d patients",
round(78*.3)),
label_right=sprintf("Control\n %d patients",
78 - round(78*.3)),
prop=.3, bjust="top",
y=attr(boxs$included, "coords")$bottom - distance)
boxs$fup_trtmnt <-
with(attr(boxs$groups, "coords"),
boxGrob("Treatment 1 year: \n - 1 patients died",
x=left_x,
bjust="bottom", y=0))
boxs$fup_control <-
with(attr(boxs$groups, "coords"),
boxGrob("Controls 1 year: \n - 2 patients died",
x=right_x,
bjust="bottom", y=0))
lapply(boxs, grid.draw)
Finally a flowchart - connecting the dots
grid.newpage()
lapply(boxs, grid.draw)
connectGrob(start=boxs$start_pop, end=boxs$included,
type="v")
connectGrob(start=boxs$start_pop, end=boxs$excluded,
type="L")
connectGrob(start=boxs$included, end=boxs$groups,
type="v")
connectGrob(start=boxs$groups, end=boxs$fup_trtmnt,
type="v", subelmnt="left")
connectGrob(start=boxs$groups, end=boxs$fup_control,
type="v", subelmnt="right")
Smoothness is fiction part 1
grid.newpage()
no_points <- c(100)
clrs <- colorRampPalette(c("darkred", "darkblue"))(length(no_points))
for (i in length(no_points):1) {
l <-
data.frame(x = c(.1, -.1, .6, 1),
y = c(.9, -.5, 0, 1)) %>%
gnrlBezierPoints(length_out = no_points[i])
grid.lines(l[,1], l[,2],
gp=gpar(col=clrs[i], lwd = 4))
}
Smoothness is fiction part 2
grid.newpage()
no_points <- c(100, 10)
clrs <- colorRampPalette(c("darkred", "darkblue"))(length(no_points))
for (i in length(no_points):1) {
l <-
data.frame(x = c(.1, -.1, .6, 1),
y = c(.9, -.5, 0, 1)) %>%
gnrlBezierPoints(length_out = no_points[i])
grid.lines(l[,1], l[,2],
gp=gpar(col=clrs[i], lwd = 4))
}
Smoothness is fiction part 3
grid.newpage()
no_points <- c(100, 10, 5)
clrs <- colorRampPalette(c("darkred", "darkblue"))(length(no_points))
for (i in length(no_points):1) {
l <-
data.frame(x = c(.1, -.1, .6, 1),
y = c(.9, -.5, 0, 1)) %>%
gnrlBezierPoints(length_out = no_points[i])
grid.lines(l[,1], l[,2],
gp=gpar(col=clrs[i], lwd = 4))
}
Summary
- Perfect positioning
- Encapsulate into grobs
- Build complexity within viewports
- Sky is the limit
