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Read, write and join or combine images. All image functions are vectorized, meaning they operate either on a single frame or a series of frames (e.g. a collage, video, or animation). Besides paths and URLs, image_read() supports commonly used bitmap and raster object types.

Usage

image_read(
  path,
  density = NULL,
  depth = NULL,
  strip = FALSE,
  coalesce = TRUE,
  defines = NULL
)

image_read_svg(path, width = NULL, height = NULL)

image_read_pdf(path, pages = NULL, density = 300, password = "")

image_read_video(path, fps = 1, format = "png")

image_write(
  image,
  path = NULL,
  format = NULL,
  quality = NULL,
  depth = NULL,
  density = NULL,
  comment = NULL,
  flatten = FALSE,
  defines = NULL,
  compression = NULL
)

image_convert(
  image,
  format = NULL,
  type = NULL,
  colorspace = NULL,
  depth = NULL,
  antialias = NULL,
  matte = NULL,
  interlace = NULL
)

image_data(image, channels = NULL, frame = 1)

image_raster(image, frame = 1, tidy = TRUE)

image_display(image, animate = TRUE)

image_browse(image, browser = getOption("browser"))

image_strip(image)

image_blank(width, height, color = "none", pseudo_image = "", defines = NULL)

image_destroy(image)

image_join(...)

image_attributes(image)

image_get_artifact(image, artifact = "")

demo_image(path)

Arguments

path

a file, url, or raster object or bitmap array

density

resolution to render pdf or svg

depth

color depth (either 8 or 16)

strip

drop image comments and metadata

coalesce

automatically image_coalesce() gif images

defines

a named character vector with extra options to control reading. These are the -define key{=value} settings in the command line tool. Use an empty string for value-less defines, and NA to unset a define.

width

in pixels

height

in pixels

pages

integer vector with page numbers. Defaults to all pages.

password

user password to open protected pdf files

fps

how many images to capture per second of video. Set to NULL to get all frames from the input video.

format

output format such as "png", "jpeg", "gif", "rgb" or "rgba".

image

magick image object returned by image_read() or image_graph()

quality

number between 0 and 100 for jpeg quality. Defaults to 75.

comment

text string added to the image metadata for supported formats

flatten

should image be flattened before writing? This also replaces transparency with background color.

compression

a string with compression type from compress_types

type

string with imagetype value from image_types for example grayscale to convert into black/white

colorspace

string with a colorspace from colorspace_types for example "gray", "rgb" or "cmyk"

antialias

enable anti-aliasing for text and strokes

matte

set to TRUE or FALSE to enable or disable transparency

interlace

string with interlace

channels

string with image channel(s) for example "rgb", "rgba", "cmyk","gray", or "ycbcr". Default is either "gray", "rgb" or "rgba" depending on the image

frame

integer setting which frame to extract from the image

tidy

converts raster data to long form for use with geom_raster. If FALSE output is the same as as.raster().

animate

support animations in the X11 display

browser

argument passed to browseURL

color

a valid color string such as "navyblue" or "#000080". Use "none" for transparency.

pseudo_image

string with pseudo image specification for example "radial-gradient:purple-yellow"

...

several images or lists of images to be combined

artifact

string with name of the artifact to extract, see the image_deskew for an example.

Details

All standard base vector methods such as [, [[, c(), as.list(), as.raster(), rev(), length(), and print() can be used to work with magick image objects. Use the standard img[i] syntax to extract a subset of the frames from an image. The img[[i]] method is an alias for image_data() which extracts a single frame as a raw bitmap matrix with pixel values.

For reading svg or pdf it is recommended to use image_read_svg() and image_read_pdf() if the rsvg and pdftools R packages are available. These functions provide more rendering options (including rendering of literal svg) and better quality than built-in svg/pdf rendering delegates from imagemagick itself.

X11 is required for image_display() which is only works on some platforms. A more portable method is image_browse() which opens the image in a browser. RStudio has an embedded viewer that does this automatically which is quite nice.

Image objects are automatically released by the garbage collector when they are no longer reachable. Because the GC only runs once in a while, you can also call image_destroy() explicitly to release the memory immediately. This is usually only needed if you create a lot of images in a short period of time, and you might run out of memory.

Examples

# Download image from the web
frink <- image_read("https://jeroen.github.io/images/frink.png")
worldcup_frink <- image_fill(frink, "orange", "+100+200", 20)
image_write(worldcup_frink, "output.png")

# extract raw bitmap array
bitmap <- frink[[1]]

# replace pixels with #FF69B4 ('hot pink') and convert back to image
bitmap[,50:100, 50:100] <- as.raw(c(0xff, 0x69, 0xb4, 0xff))
image_read(bitmap)
#> # A tibble: 1 × 7
#>   format width height colorspace matte filesize density
#>   <chr>  <int>  <int> <chr>      <lgl>    <int> <chr>  
#> 1 PNG      220    445 sRGB       TRUE         0 72x72  

# Plot to graphics device via legacy raster format
raster <- as.raster(frink)
par(ask=FALSE)
plot(raster)


# Read bitmap arrays from from other image packages
curl::curl_download("https://jeroen.github.io/images/example.webp", "example.webp")
if(require(webp)) image_read(webp::read_webp("example.webp"))
#> Loading required package: webp
#> # A tibble: 1 × 7
#>   format width height colorspace matte filesize density
#>   <chr>  <int>  <int> <chr>      <lgl>    <int> <chr>  
#> 1 PNG      550    404 sRGB       TRUE         0 72x72  
unlink(c("example.webp", "output.png"))
if(require(rsvg)){
tiger <- image_read_svg("http://jeroen.github.io/images/tiger.svg")
svgtxt <- '<?xml version="1.0" encoding="UTF-8"?>
<svg width="400" height="400" viewBox="0 0 400 400" fill="none">
 <circle fill="steelblue" cx="200" cy="200" r="100" />
 <circle fill="yellow" cx="200" cy="200" r="90" />
</svg>'
circles <- image_read_svg(svgtxt)
}
#> Loading required package: rsvg
#> Linking to librsvg 2.48.9
if(require(pdftools))
image_read_pdf(file.path(R.home('doc'), 'NEWS.pdf'), pages = 1, density = 100)
#> Loading required package: pdftools
#> Using poppler version 0.86.1
#> # A tibble: 1 × 7
#>   format width height colorspace matte filesize density
#>   <chr>  <int>  <int> <chr>      <lgl>    <int> <chr>  
#> 1 PNG      850   1100 sRGB       TRUE         0 100x100
# create a solid canvas
image_blank(600, 400, "green")
#> # A tibble: 1 × 7
#>   format width height colorspace matte filesize density
#>   <chr>  <int>  <int> <chr>      <lgl>    <int> <chr>  
#> 1 png      600    400 sRGB       FALSE        0 72x72  
image_blank(600, 400, pseudo_image = "radial-gradient:purple-yellow")
#> # A tibble: 1 × 7
#>   format          width height colorspace matte filesize density
#>   <chr>           <int>  <int> <chr>      <lgl>    <int> <chr>  
#> 1 RADIAL-GRADIENT   600    400 sRGB       FALSE        0 72x72  
image_blank(200, 200, pseudo_image = "gradient:#3498db-#db3a34",
  defines = c('gradient:direction' = 'east'))
#> # A tibble: 1 × 7
#>   format   width height colorspace matte filesize density
#>   <chr>    <int>  <int> <chr>      <lgl>    <int> <chr>  
#> 1 GRADIENT   200    200 sRGB       FALSE        0 72x72