How Do You Make the Code of a Photo to Show Up as a Photo Again in R
The magick packet provide a modern and simple toolkit for image processing in R. It wraps the ImageMagick STL which is the most comprehensive open-source image processing library available today.
The ImageMagick library has an overwhelming amount of functionality. Magick exposes a decent subset of it, but information technology is impossible to document everything in detail. This article introduces some basic concepts and examples to become started.
Installing magick
On Windows or macOS the parcel is nearly hands installed via CRAN.
install.packages("magick") The binary CRAN packages work out of the box and take most important features enabled. Use magick_config to run into which features and formats are supported by your version of ImageMagick.
library(magick) ## Linking to ImageMagick 6.9.12.3 ## Enabled features: cairo, fontconfig, freetype, heic, lcms, pango, raw, rsvg, webp ## Disabled features: fftw, ghostscript, x11 str(magick::magick_config()) ## Listing of 24 ## $ version :Form 'numeric_version' subconscious list of 1 ## ..$ : int [i:4] 6 9 12 3 ## $ modules : logi FALSE ## $ cairo : logi TRUE ## $ fontconfig : logi TRUE ## $ freetype : logi Truthful ## $ fftw : logi FALSE ## $ ghostscript : logi Fake ## $ heic : logi TRUE ## $ jpeg : logi TRUE ## $ lcms : logi Truthful ## $ libopenjp2 : logi TRUE ## $ lzma : logi TRUE ## $ pangocairo : logi TRUE ## $ pango : logi Truthful ## $ png : logi TRUE ## $ raw : logi TRUE ## $ rsvg : logi TRUE ## $ tiff : logi True ## $ webp : logi Truthful ## $ wmf : logi FALSE ## $ x11 : logi Fake ## $ xml : logi Truthful ## $ nil-configuration: logi TRUE ## $ threads : int 1 Build from source
On Linux you demand to install the ImageMagick++ library: on Debian/Ubuntu this is called libmagick++-dev:
sudo apt-get install libmagick++-dev On Fedora or CentOS/RHEL we demand ImageMagick-c++-devel:
sudo yum install ImageMagick-c++-devel To install from source on macOS yous need imagemagick@six from homebrew.
brew install imagemagick@6 Unfortunately the current imagemagick@6 configuration on homebrew disables a bunch of features, including librsvg and fontconfig. Therefore the quality of fonts and svg rendering might exist suboptimal. The is not a problem for the CRAN binary bundle.
Epitome IO
What makes magick so magical is that it automatically converts and renders all common prototype formats. ImageMagick supports dozens of formats and automatically detects the type. Use magick::magick_config() to list the formats that your version of ImageMagick supports.
Read and write
Images can be read directly from a file path, URL, or raw vector with image data with image_read. The image_info office shows some meta information about the image, similar to the imagemagick identify command line utility.
library(magick) tiger <- image_read_svg('http://jeroen.github.io/images/tiger.svg', width = 350) impress(tiger) ## format width height colorspace matte filesize density ## 1 PNG 350 350 sRGB TRUE 0 72x72
Nosotros use image_write to export an image in any format to a file on disk, or in retention if path = NULL.
# Render svg to png bitmap image_write(tiger, path = "tiger.png", format = "png") If path is a filename, image_write returns path on success such that the consequence can be piped into part taking a file path.
Converting formats
Magick keeps the image in memory in its original format. Specify the format parameter image_write to convert to another format. You lot tin can as well internally convert the image to another format before, earlier applying transformations. This tin be useful if your original format is lossy.
tiger_png <- image_convert(tiger, "png") image_info(tiger_png) ## format width pinnacle colorspace matte filesize density ## 1 PNG 350 350 sRGB TRUE 0 72x72 Note that size is currently 0 considering ImageMagick is lazy (in the good sense) and does non render until information technology has to.
Preview
IDE's with a congenital-in web browser (such as RStudio) automatically display magick images in the viewer. This results in a great interactive image editing environment.
Alternatively, on Linux you tin can use image_display to preview the image in an X11 window. Finally image_browse opens the image in your system's default application for a given type.
# X11 only image_display(tiger) # System dependent image_browse(tiger) Another method is converting the image to a raster object and plot it on R's graphics brandish. However this is very tiresome and only useful in combination with other plotting functionality. Run into #raster beneath.
Transformations
The best way to become a sense of available transformations is walk through the examples in the ?transformations assist page in RStudio. Below a few examples to get a sense of what is possible.
Cut and edit
Several of the transformation functions accept an geometry parameter which requires a special syntax of the form AxB+C+D where each element is optional. Some examples:
-
image_crop(image, "100x150+50"): crop outwidth:100pxandheight:150pxstarting+50pxfrom the left -
image_scale(prototype, "200"): resize proportionally to width:200px -
image_scale(epitome, "x200"): resize proportionally to height:200px -
image_fill(image, "blueish", "+100+200"): overflowing fill with blue starting at the betoken atx:100, y:200 -
image_border(frink, "carmine", "20x10"): adds a border of 20px left+correct and 10px pinnacle+bottom
The full syntax is specified in the Magick::Geometry documentation.
# Example paradigm frink <- image_read("https://jeroen.github.io/images/frink.png") impress(frink) ## format width pinnacle colorspace matte filesize density ## 1 PNG 220 445 sRGB TRUE 73494 72x72
# Add together 20px left/right and 10px top/bottom image_border(image_background(frink, "hotpink"), "#000080", "20x10")
# Trim margins image_trim(frink)
# Passport pica image_crop(frink, "100x150+50") 
# Resize image_scale(frink, "300") # width: 300px
image_scale(frink, "x300") # peak: 300px 
# Rotate or mirror image_rotate(frink, 45)
image_flip(frink)
image_flop(frink)
# Brightness, Saturation, Hue image_modulate(frink, brightness = lxxx, saturation = 120, hue = 90)
# Paint the shirt orange image_fill(frink, "orangish", indicate = "+100+200", fuzz = 20)
With image_fill we tin can flood fill starting at pixel point. The fuzz parameter allows for the fill to cantankerous for adjacent pixels with similarish colors. Its value must be betwixt 0 and 256^2 specifying the max geometric distance between colors to be considered equal. Hither we give professor frink an orange shirt for the World Loving cup.
Filters and effects
ImageMagick also has a agglomeration of standard effects that are worth checking out.
# Add randomness image_blur(frink, 10, 5)
image_noise(frink)
# Silly filters image_charcoal(frink) 
image_oilpaint(frink)
image_negate(frink)
Kernel convolution
The image_convolve() function applies a kernel over the image. Kernel convolution means that each pixel value is recalculated using the weighted neighborhood sum defined in the kernel matrix. For example lets wait at this simple kernel:
kern <- matrix(0, ncol = 3, nrow = 3) kern[1, two] <- 0.25 kern[2, c(1, 3)] <- 0.25 kern[3, two] <- 0.25 kern ## [,1] [,two] [,3] ## [1,] 0.00 0.25 0.00 ## [2,] 0.25 0.00 0.25 ## [3,] 0.00 0.25 0.00 This kernel changes each pixel to the mean of its horizontal and vertical neighboring pixels, which results in a slight blurring effect in the right-manus image beneath:
img <- image_resize(logo, "300x300") img_blurred <- image_convolve(img, kern) image_append(c(img, img_blurred)) 
Or employ whatsoever of the standard kernels
img %>% image_convolve('Sobel') %>% image_negate() 
img %>% image_convolve('DoG:0,0,2') %>% image_negate() 
Text notation
Finally information technology can be useful to print some text on meridian of images:
# Add some text image_annotate(frink, "I similar R!", size = seventy, gravity = "southwest", color = "green")
# Customize text image_annotate(frink, "CONFIDENTIAL", size = xxx, color = "red", boxcolor = "pink", degrees = sixty, location = "+50+100")
# Fonts may crave ImageMagick has fontconfig image_annotate(frink, "The quick brownish fob", font = 'Times', size = 30)
Fonts that are supported on most platforms include "sans", "mono", "serif", "Times", "Helvetica", "Trebuchet", "Georgia", "Palatino"or "Comic Sans".
Combining with pipes
Each of the epitome transformation functions returns a modified re-create of the original paradigm. It does not affect the original prototype.
frink <- image_read("https://jeroen.github.io/images/frink.png") frink2 <- image_scale(frink, "100") image_info(frink) ## format width height colorspace matte filesize density ## 1 PNG 220 445 sRGB Truthful 73494 72x72 image_info(frink2) ## format width top colorspace matte filesize density ## 1 PNG 100 202 sRGB TRUE 0 72x72 Hence to combine transformations you need to concatenation them:
examination <- image_rotate(frink, ninety) examination <- image_background(examination, "bluish", flatten = Truthful) test <- image_border(test, "red", "10x10") examination <- image_annotate(examination, "This is how nosotros combine transformations", colour = "white", size = xxx) print(exam) ## format width summit colorspace matte filesize density ## 1 PNG 465 240 sRGB TRUE 0 72x72
Using magrittr pipage syntax makes it a bit more readable
image_read("https://jeroen.github.io/images/frink.png") %>% image_rotate(270) %>% image_background("bluish", flatten = TRUE) %>% image_border("crimson", "10x10") %>% image_annotate("The same matter with pipes", color = "white", size = thirty)
Epitome Vectors
The examples above business organization single images. Still all functions in magick accept been vectorized to back up working with layers, compositions or animation.
The standard base methods [ [[, c() and length() are used to manipulate vectors of images which can then be treated as layers or frames.
# Download earth gif and make it a flake smaller for vignette globe <- image_read("https://jeroen.github.io/images/world.gif") %>% image_scale("200x") %>% image_quantize(128) length(earth) ## [ane] 44 globe
head(image_info(earth)) ## format width height colorspace matte filesize density ## 1 GIF 200 200 RGB Imitation 0 72x72 ## 2 GIF 200 200 RGB TRUE 0 72x72 ## 3 GIF 200 200 RGB TRUE 0 72x72 ## 4 GIF 200 200 RGB Truthful 0 72x72 ## 5 GIF 200 200 RGB True 0 72x72 ## 6 GIF 200 200 RGB True 0 72x72 rev(earth) %>% image_flip() %>% image_annotate("meanwhile in Australia", size = 20, color = "white")
Layers
We can stack layers on summit of each other as nosotros would in Photoshop:
bigdata <- image_read('https://jeroen.github.io/images/bigdata.jpg') frink <- image_read("https://jeroen.github.io/images/frink.png") logo <- image_read("https://jeroen.github.io/images/Rlogo.png") img <- c(bigdata, logo, frink) img <- image_scale(img, "300x300") image_info(img) ## format width elevation colorspace matte filesize density ## i JPEG 300 225 sRGB Imitation 0 72x72 ## two PNG 300 232 sRGB TRUE 0 72x72 ## 3 PNG 148 300 sRGB Truthful 0 72x72 A mosaic prints images on pinnacle of one another, expanding the output sheet such that that everything fits:
image_mosaic(img)
Flattening combines the layers into a single prototype which has the size of the first epitome:
image_flatten(img)
Flattening and mosaic let for specifying alternative composite operators:
image_flatten(img, 'Add together')
image_flatten(img, 'Modulate') 
image_flatten(img, 'Minus') 
Combining
Appending means simply putting the frames side by side to each other:
image_append(image_scale(img, "x200"))
Use stack = TRUE to position them on elevation of each other:
image_append(image_scale(img, "100"), stack = TRUE) 
Composing allows for combining 2 images on a specific position:
bigdatafrink <- image_scale(image_rotate(image_background(frink, "none"), 300), "x200") image_composite(image_scale(bigdata, "x400"), bigdatafrink, starting time = "+180+100")
Pages
When reading a PDF document, each page becomes an element of the vector. Note that PDF gets rendered while reading so you lot demand to specify the density immediately.
manual <- image_read_pdf('https://cloud.r-project.org/web/packages/magick/magick.pdf', density = 72) image_info(manual) ## format width height colorspace matte filesize density ## 1 PNG 612 792 sRGB TRUE 0 72x72 ## 2 PNG 612 792 sRGB True 0 72x72 ## iii PNG 612 792 sRGB TRUE 0 72x72 ## 4 PNG 612 792 sRGB TRUE 0 72x72 ## 5 PNG 612 792 sRGB Truthful 0 72x72 ## 6 PNG 612 792 sRGB TRUE 0 72x72 ## vii PNG 612 792 sRGB True 0 72x72 ## 8 PNG 612 792 sRGB TRUE 0 72x72 ## nine PNG 612 792 sRGB Truthful 0 72x72 ## 10 PNG 612 792 sRGB True 0 72x72 ## 11 PNG 612 792 sRGB True 0 72x72 ## 12 PNG 612 792 sRGB TRUE 0 72x72 ## xiii PNG 612 792 sRGB TRUE 0 72x72 ## xiv PNG 612 792 sRGB TRUE 0 72x72 ## 15 PNG 612 792 sRGB TRUE 0 72x72 ## sixteen PNG 612 792 sRGB True 0 72x72 ## 17 PNG 612 792 sRGB True 0 72x72 ## 18 PNG 612 792 sRGB TRUE 0 72x72 ## 19 PNG 612 792 sRGB Truthful 0 72x72 ## 20 PNG 612 792 sRGB TRUE 0 72x72 ## 21 PNG 612 792 sRGB TRUE 0 72x72 ## 22 PNG 612 792 sRGB TRUE 0 72x72 ## 23 PNG 612 792 sRGB TRUE 0 72x72 ## 24 PNG 612 792 sRGB TRUE 0 72x72 ## 25 PNG 612 792 sRGB True 0 72x72 ## 26 PNG 612 792 sRGB TRUE 0 72x72 ## 27 PNG 612 792 sRGB TRUE 0 72x72 ## 28 PNG 612 792 sRGB TRUE 0 72x72 ## 29 PNG 612 792 sRGB TRUE 0 72x72 ## 30 PNG 612 792 sRGB TRUE 0 72x72 ## 31 PNG 612 792 sRGB TRUE 0 72x72 ## 32 PNG 612 792 sRGB TRUE 0 72x72 ## 33 PNG 612 792 sRGB Truthful 0 72x72 ## 34 PNG 612 792 sRGB Truthful 0 72x72 ## 35 PNG 612 792 sRGB True 0 72x72 ## 36 PNG 612 792 sRGB TRUE 0 72x72 ## 37 PNG 612 792 sRGB TRUE 0 72x72 ## 38 PNG 612 792 sRGB TRUE 0 72x72 ## 39 PNG 612 792 sRGB True 0 72x72 ## 40 PNG 612 792 sRGB Truthful 0 72x72 ## 41 PNG 612 792 sRGB TRUE 0 72x72 ## 42 PNG 612 792 sRGB True 0 72x72 ## 43 PNG 612 792 sRGB Truthful 0 72x72 ## 44 PNG 612 792 sRGB TRUE 0 72x72 manual[1]
Animation
Instead of treating vector elements as layers, we can also make them frames in an animation!
image_animate(image_scale(img, "200x200"), fps = 1, dispose = "previous") 
Morphing creates a sequence of n images that gradually morph one prototype into another. It makes animations
newlogo <- image_scale(image_read("https://jeroen.github.io/images/Rlogo.png")) oldlogo <- image_scale(image_read("https://jeroen.github.io/images/Rlogo-erstwhile.png")) image_resize(c(oldlogo, newlogo), '200x150!') %>% image_background('white') %>% image_morph() %>% image_animate(optimize = TRUE)
If y'all read in an existing GIF or Video file, each frame becomes a layer:
# Foreground image assistant <- image_read("https://jeroen.github.io/images/banana.gif") banana <- image_scale(banana, "150") image_info(banana) ## format width height colorspace matte filesize density ## one GIF 150 148 sRGB True 0 72x72 ## 2 GIF 150 148 sRGB Truthful 0 72x72 ## 3 GIF 150 148 sRGB TRUE 0 72x72 ## iv GIF 150 148 sRGB TRUE 0 72x72 ## 5 GIF 150 148 sRGB Truthful 0 72x72 ## half dozen GIF 150 148 sRGB True 0 72x72 ## 7 GIF 150 148 sRGB TRUE 0 72x72 ## viii GIF 150 148 sRGB True 0 72x72 Manipulate the individual frames and put them back into an blitheness:
# Background prototype background <- image_background(image_scale(logo, "200"), "white", flatten = Truthful) # Combine and flatten frames frames <- image_composite(background, banana, start = "+70+30") # Turn frames into animation animation <- image_animate(frames, fps = 10, optimize = Truthful) print(animation) ## format width height colorspace matte filesize density ## 1 gif 200 155 sRGB TRUE 0 72x72 ## two gif 94 105 sRGB TRUE 0 72x72 ## 3 gif 125 122 sRGB True 0 72x72 ## 4 gif 108 118 sRGB Truthful 0 72x72 ## 5 gif 108 105 sRGB TRUE 0 72x72 ## 6 gif 92 105 sRGB Truthful 0 72x72 ## vii gif 113 123 sRGB True 0 72x72 ## 8 gif 119 118 sRGB Truthful 0 72x72
Animations can be saved every bit GIF of MPEG files:
image_write(animation, "Rlogo-assistant.gif") Drawing and Graphics
A relatively recent addition to the package is a native R graphics device which produces a magick epitome object. This tin can either exist used like a regular device for making plots, or alternatively to open a device which draws onto an existing image using pixel coordinates.
Graphics device
The image_graph() function opens a new graphics device similar to eastward.chiliad.png() or x11(). It returns an image object to which the plot(s) will be written. Each "page" in the plotting device volition become a frame in the prototype object.
# Produce paradigm using graphics device fig <- image_graph(width = 400, height = 400, res = 96) ggplot2::qplot(mpg, wt, information = mtcars, colour = cyl) dev.off() We can easily post-process the figure using regular prototype operations.
# Combine out <- image_composite(fig, frink, start = "+70+thirty") impress(out) ## # A tibble: 1 × 7 ## format width superlative colorspace matte filesize density ## <chr> <int> <int> <chr> <lgl> <int> <chr> ## ane PNG 400 400 sRGB TRUE 0 96x96
Drawing device
Another style to apply the graphics device is to draw on top of an exiting image using pixel coordinates.
# Or paint over an existing paradigm img <- image_draw(frink) rect(20, 20, 200, 100, border = "cerise", lty = "dashed", lwd = 5) abline(h = 300, col = 'blue', lwd = 'ten', lty = "dotted") text(30, 250, "Hoiven-Glaven", family = "monospace", cex = 4, srt = ninety) palette(rainbow(11, end = 0.9)) symbols(rep(200, 11), seq(0, 400, 40), circles = runif(xi, 5, 35), bg = i:11, inches = Imitation, add together = TRUE) dev.off() print(img) ## # A tibble: 1 × seven ## format width height colorspace matte filesize density ## <chr> <int> <int> <chr> <lgl> <int> <chr> ## 1 PNG 220 445 sRGB TRUE 0 72x72
By default image_draw() sets all margins to 0 and uses graphics coordinates to match image size in pixels (width x height) where (0,0) is the superlative left corner. Notation that this ways the y centrality increases from top to bottom which is the opposite of typical graphics coordinates. Yous tin override all this past passing custom xlim, ylim or mar values to image_draw.
Blithe Graphics
The graphics device supports multiple frames which makes it easy to create blithe graphics. The code below shows how you would implement the example from the very cool gganimate packet using the magick graphics device.
library(gapminder) library(ggplot2) img <- image_graph(600, 340, res = 96) datalist <- split(gapminder, gapminder$year) out <- lapply(datalist, function(data){ p <- ggplot(data, aes(gdpPercap, lifeExp, size = popular, colour = continent)) + scale_size("population", limits = range(gapminder$popular)) + geom_point() + ylim(20, 90) + scale_x_log10(limits = range(gapminder$gdpPercap)) + ggtitle(data$year) + theme_classic() print(p) }) dev.off() animation <- image_animate(img, fps = 2, optimize = TRUE) print(animation) ## # A tibble: 12 × seven ## format width height colorspace matte filesize density ## <chr> <int> <int> <chr> <lgl> <int> <chr> ## one gif 600 340 sRGB TRUE 0 96x96 ## 2 gif 385 243 sRGB Truthful 0 96x96 ## 3 gif 395 237 sRGB TRUE 0 96x96 ## 4 gif 374 232 sRGB TRUE 0 96x96 ## v gif 393 225 sRGB Truthful 0 96x96 ## 6 gif 373 234 sRGB TRUE 0 96x96 ## 7 gif 354 234 sRGB Truthful 0 96x96 ## eight gif 308 210 sRGB Truthful 0 96x96 ## ix gif 320 260 sRGB TRUE 0 96x96 ## 10 gif 331 218 sRGB Truthful 0 96x96 ## 11 gif 356 208 sRGB True 0 96x96 ## 12 gif 347 208 sRGB True 0 96x96
To write information technology to a file y'all would merely do:
image_write(blitheness, "gapminder.gif") Raster Images
Magick images can besides be converted to raster objects for utilise with R'due south graphics device. Thereby we tin can combine it with other graphics tools. Nonetheless do note that R's graphics device is very slow and has a very different coordinate system which reduces the quality of the paradigm.
Base of operations R rasters
Base R has an as.raster format which converts the image to a vector of strings. The paper Raster Images in R Graphics past Paul Murrell gives a nice overview.
plot(every bit.raster(frink))
# Impress over another graphic plot(cars) rasterImage(frink, 21, 0, 25, 80)
The filigree package
The grid packet makes it easier to overlay a raster on the graphics device without having to adapt for the x/y coordinates of the plot.
library(ggplot2) library(grid) qplot(speed, dist, information = cars, geom = c("point", "shine")) ## `geom_smooth()` using method = 'loess' and formula 'y ~ x' grid.raster(frink)
forehandproff1944.blogspot.com
Source: https://cran.r-project.org/package=magick/vignettes/intro.html
0 Response to "How Do You Make the Code of a Photo to Show Up as a Photo Again in R"
Post a Comment