I want to build a tiff file with text only and no margins around the text, using R.
I tried :
library(ggplot2)
plt <- ggplot() +
geom_text(aes(x=0,y=0,label="test")) +
theme_void()
ggsave(plt,filename="test.tif",bg="transparent")
However, there are large margins (I have added the borderline to highlight these margins):
What I want to get is a file with the image of the text, without any margin:
Is there a way to create such a tiff file, using ggplot, plot or any other R function?
This is pretty close, in base R: thanks to @r2evans for code to auto-adjust the width/height of the image:
txt <- "hello world"
tiff("test.tiff", strwidth(txt, units="in"),
strheight(txt, units="in"), units="in", res=300)
par(mar = rep(0,4))
plot(0:1, 0:1, type = "n", ann = FALSE, axes=FALSE)
text(0.5, 0.5, txt)
dev.off()
txt <- "hello world"; dev.new(); tiff("test.tiff", strwidth(txt, units="in"), strheight(txt, units="in"), units="in", res=300); par(..); plot(..); text(0.5, 0.5, txt); dev.off(). The call to dev.new() is purely to have a base-graphics canvas available, we don't need anything in it.
strwidth()/strheight() but hadn't quite gotten there yet.
dev.new() is redundant. Also, plot.new(); plot.window(0:1, 0:1) instead plot() might be more concise.dev.new() may not be redundant for RStudio IDE users? I believe the IDE does a lot of trickery under the hood for graphics management ... perhaps if (!length(dev.list())) dev.new() insteaddev.new(). I'm on Linux though.You can use the library magick with an empty canvas - annotate text and trim of the margins and it will give
I tried methods described here and here but they used R's devices like tiff but the strwidth / strheight methods were very unsatisfactory, also aligning the text along a grid or even ggplot2 turned out to still leave unwanted margins or even cut off text.
words <- c("The", "Turing", "test,", "originally", "called", "the", "imitation",
"game", "by", "Alan", "Turing", "in", "1949,[2]", "is", "a",
"test", "of", "a", "machine's", "ability", "a", "b", "c", "d",
"e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q",
"r", "s", "t", "u", "v", "w", "x", "y", "z")
library(magick)
text2tiff <- function(
text,
font_size = 500,
font_family = "Arial",
backgroundColor = "white",
textColor = "black")
{
width <- ceiling(strwidth(text, units = "inches", family = font_family,ps = par(ps = font_size)) * 96 + 200)
height <- ceiling(strheight(text, units = "inches", family = font_family, ps = par(ps = font_size)) * 96 + 200)
canvas <- image_blank(width = width, height = height, color = backgroundColor)
text_image <- image_annotate(canvas, # Annotate text
text,
font = font_family,
size = font_size,
color = textColor,
gravity = "center")
image_write(image_trim(text_image), # Trim image to remove margins
path = paste0(gsub("[^[:alnum:]]", "", text), ".tiff"), # take text as img name
format = "tiff")
}
for(i in 1:length(words)) text2tiff(words[i])
Update: Thanks for your comment: According to the answer of @Tim G we could us ggplot and magick :
library(ggplot2)
library(magick)
plt <- ggplot() +
geom_text(aes(x = 0, y = 0, label = "hello world"), size = 10) +
scale_x_continuous(expand = c(0, 0)) +
scale_y_continuous(expand = c(0, 0)) +
theme_void() +
theme(plot.margin = margin(0, 0, 0, 0, "pt"))
# temporary file
temp_file <- tempfile(fileext = ".tif")
ggsave(temp_file, plot = plt, bg = "white",
width = 4, height = 2, units = "in", dpi = 300)
img <- image_read(temp_file)
img_cropped <- image_trim(img) # Crop the image to remove whitespace
image_write(img_cropped, "test_cropped.tif") # Save the cropped image
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First answer:
With `ggplot2` we could remove extra space by setting `expand = c(0,0)` and remove some padding by setting `plot.margin()`:
library(ggplot2)
library(grid)
plt <- ggplot() +
geom_text(aes(x = 0, y = 0, label = "hello world"), size = 10) +
scale_x_continuous(expand = c(0, 0)) +
scale_y_continuous(expand = c(0, 0)) +
theme_void() +
theme(plot.margin = margin(0, 0, 0, 0, "pt"))
ggsave("test.tif", plot = plt, bg = "white",
width = 2, height = 1, units = "in", dpi = 300)
