Save png of ggplot2 object with no margins

Question

I am writing a web application which needs precise dimensions for its figures. I decided to make the figures with ggplot2 because they require specialized text from R. I would like for the figures created to have no margins as they will be rotated via JavaScript. I used this page for an idea of how to cut down on the margins: https://kohske.wordpress.com/2010/12/25/drawing-on-full-region-in-ggplot2/ but was unable to print to a .png file without borders. Here's the sample code.

library(ggplot2)
library(gtable)

circle <- function(center = c(0,0),diameter = 1, npoints = 100){
  r = diameter / 2
  tt <- seq(0,2*pi,length.out = npoints)
  xx <- center[1] + r * cos(tt)
  yy <- center[2] + r * sin(tt)
  data.frame(x = xx, y = yy)
}



dat <- circle(c(0,0),1,npoints = 1000)

plot1 <- ggplot(dat,aes(x,y)) + 
  geom_path() +
  theme(axis.text.y=element_blank(),
        axis.text.x=element_blank(),
        axis.ticks=element_blank(),
        axis.ticks.length = unit(0,"null"),
        axis.ticks.margin = unit(0,"null"),
        axis.title.x=element_blank(),
        axis.title.y=element_blank(),
        legend.position="none",
        panel.background = element_blank(),
        panel.grid = element_blank(),
        title = element_blank(),
        panel.grid.major = element_blank(),
        panel.grid.minor = element_blank(),
        panel.margin = unit(0,"null"),
        plot.margin = rep(unit(0,"null"),4),
        axis.ticks.length = unit(0,"cm"),
        axis.ticks.margin = unit(0,"cm"))

png("plot.png", width=434, height=434)
print(plot1)
dev.off()

This outputs a circle with a decent sized border. Let me be precise about what I would like, a png which is 434x434 px with a circle which has no borders (e.g. the diameter of the circle is 434px). I could create a larger file then crop it down, but I will be making ~50 of these graphics. Thanks for your help!

You could select just the plot panel from the ggplot layout. [See when-using-ggplot-in-r-how-do-i-remove-margins-surrounding-the-plot-area](http://stackoverflow.com/questions/31254533/when-using-ggplot-in-r-how-do-i-remove-margins-surrounding-the-plot-area/31256788#31256788) — Sandy Muspratt, Sep 28 '15 at 21:02

score 2 · Accepted Answer · answered Sep 28 '15 at 01:35

2

You can also do:

scale_x_continuous(expand=c(0,0)) +
scale_y_continuous(expand=c(0,0)) +
labs(x=NULL, y=NULL, title=NULL) +

answered Sep 28 '15 at 01:35

hrbrmstr

77,368
11
139
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score 1 · Answer 2 · answered Sep 28 '15 at 01:33

1

You can get rid of the margin by changing your plot.margin to this:

plot.margin = unit(rep(-1.25,4),"lines"),

answered Sep 28 '15 at 01:33

eipi10

91,525
24
209
285

score 0 · Answer 3 · answered Sep 28 '15 at 01:49

library(ggplot2)
library(gtable)

circle <- function(center = c(0,0),diameter = 1, npoints = 100){
  r = diameter / 2
  tt <- seq(0,2*pi,length.out = npoints)
  xx <- center[1] + r * cos(tt)
  yy <- center[2] + r * sin(tt)
  data.frame(x = xx, y = yy)
}

dat <- circle(c(0,0),0.5,npoints = 1000)

plot1 <- par(mar=c(0,0,0,0))
plot1 <- ggplot(dat,aes(x,y)) + 
  geom_path() +
  theme(axis.text.y=element_blank(),panel.margin = unit(c(0,0,0,0), "lines"),
        axis.text.x=element_blank(),
        axis.ticks=element_blank(),
        axis.ticks.length = unit(0,"null"),
        axis.ticks.margin = unit(0,"null"),
        axis.title.x=element_blank(),
        axis.title.y=element_blank(),
        legend.position="none",
        panel.background = element_blank(),
        panel.grid = element_blank(),
        title = element_blank(),
        panel.grid.major = element_blank(),
        panel.grid.minor = element_blank(),
        panel.margin = unit(0,"null"),
        plot.margin = rep(unit(0,"null"),4),
        axis.ticks.length = unit(0,"cm"),
        axis.ticks.margin = unit(0,"cm")) + scale_x_continuous(expand=c(0,0)) +
        scale_y_continuous(expand=c(0,0)) + labs(x=NULL, y=NULL, title=NULL)


png("plot.png", width=434, height=434)
print(plot1)
dev.off()

score 0 · Answer 4 · answered Sep 29 '15 at 09:03

0

here's another option,

library(ggplot2)
library(grid)
p <- qplot(1,1, geom="blank")+annotation_custom(circleGrob())
png("test.png", width=434, height=434)
grid.draw(ggplotGrob(p)[3,4])
dev.off()

answered Sep 29 '15 at 09:03

baptiste

75,767
19
198
294

Save png of ggplot2 object with no margins

4 Answers4