easiest way to rotate a PNG file 90 degrees within R

Question

what's the most painless way to programmatically open a PNG file on my computer, rotate it 90 degrees, then save it as another PNG file - with no loss of quality and no other changes? it's a five-second task in microsoft paint but all of the plotting, raster, image, device answers to related SO questions have me confused about the simplest way to do this? thanks

Victorp · Accepted Answer · 2017-07-07T10:11:09.757

4

Try package magick :

library(magick)
newlogo <- image_read("https://www.r-project.org/logo/Rlogo.png")
newlogo <- image_scale(newlogo, "400x400") # logo is too big

# rotate
image_rotate(newlogo, 90)

# save    
image_rotate(newlogo, 45) %>% image_write("newlogoRotated.png")

I think that's the easiest way !

edited Jul 07 '17 at 10:11

answered Jul 07 '17 at 10:01

Victorp

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Uh... why the scale? That will produce a different image – leonbloy Jul 10 '17 at 19:28
The original logo is 800x700, a little large for RStudio viewer, it's just for the demo – Victorp Jul 10 '17 at 19:34

score 1 · Answer 2 · answered Jul 21 '17 at 08:05

1

It's also possible to use the Bioconductor package EBImage, as in the following example.

library(EBImage)

# open
img <- readImage("https://www.r-project.org/logo/Rlogo.png")

# rotate
img <- rotate(img, 90)

# save    
writeImage(img, "Rlogo.png")

answered Jul 21 '17 at 08:05

aoles

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easiest way to rotate a PNG file 90 degrees within R

2 Answers2