mikefc

minisvg

minisvg is a package for building SVG documents in R.

Overview

Need to build R6 object alternate initialisation
SVG elements stag
SVG elements SVGElement$new() svg_elem()
SVG document SVGDocument$new() svg_doc()

Quick Examples

SVG Entity code result
SVG elements stag$circle(cx=0, cy=0, r=20) <circle cx="0" cy="0" r="20" />
SVG elements SVGElement$new('circle', cx=0, cy=0, r=20) <circle cx="0" cy="0" r="20" />
SVG elements svg_elem('circle', cx=0, cy=0, r=20) <circle cx="0" cy="0" r="20" />
SVG document doc <- SVGDocument$new(); doc$add('circle', cx=0, cy=0, r=20) <svg> <circle cx="0" cy="0" r="20" /></svg>
SVG document svg_doc(stag$circle(cx=0, cy=0, r=20)) <svg> <circle cx="0" cy="0" r="20" /></svg>

Installation

You can install minisvg from GitHub with:

# install.packages("devtools")
devtools::install_github("coolbutuseless/minisvg")

stag helper (autocomplete SVG element creation)

The stag helper is similar to shiny::tag and minihtml::htag

svg_prop helper (autocomplete SVG attribute creation)

The svg_prop helper uses autocomplete to help remember the property attributes of many SVG elements, along with their possible values.

Interface

  • Individual elements can be created in a number of ways. E.g. creating a defs block
    • As a stand-alone element
      • new_elem <- SVGElement$new('defs', style = 'color: black;')
      • new_elem <- svg_elem('defs', style = 'color: black;')
      • new_elem <- stag$defs(style = 'color: black;')
    • As a sub-element of an existing document or element - the element is created, added to the parent document (or element) and returned.
      • doc <- SVGDocument$new(); new_elem <- doc$add('defs', style = 'color: black;')
      • doc <- SVGDocument$new(); new_elem <- doc$defs(style = 'color: black;')
      • elem <- SVGElement$new('xxx'); new_elem <- elem$add('defs', style = 'color: black;')
      • elem <- SVGElement$new('xxx'); new_elem <- elem$defs(style = 'color: black;')
  • $add() creates an element and adds it to the parent (and returns it)
    • new_elem <- doc$add('defs')
  • $append() appends the given elements as children
    • new_elem <- stag$defs(); doc$append(new_elem, ...)
  • $new(name, ...), $update(...) and $add(name, ...) all accept ... where
    • named arguments are added as attributes of this node
    • unnamed argument are added as children of this node

Hello World SVG Example

This first example demonstrates:

  • initialising a document of a certain size
  • using methods on the SVGDocument object to create a circle
  • using the $append() method to add the border rectangle
  • creating the border rectangle using the stag$rect helper
  • using the svg_prop helper (and autocomplete) to assist in remembering what the stroke width parameter is called
  • adding text
  • adding a rotation transformation to the text
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# Create a document, add a border and a circle
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
doc <- SVGDocument$new(width = 400, height = 400)
doc$circle(cx=200, cy=200, r=100, fill = 'yellow')
doc$append(
  stag$rect(
    x = 0, y = 0, width = 400, height = 400, fill = 'none', 
    stroke = 'black', svg_prop$`stroke-width`$set(12)
  )
)

#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# Add some text to the document
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mytext <- doc$text("Hello world", x= 160, y = 210, size = 30)

#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# Manipulate the text object to add some animation to it
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mytext$animateTransform(
  attributeName = 'transform',
  type          = 'rotate',
  from          = "0 200 200",
  to            = "360 200 200",
  dur           = 5,
  repeatCount   = 'indefinite'
)
<?xml version="1.0" encoding="UTF-8"?>
<svg width="400" height="400" viewBox="0 0 400 400" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
  <circle fill="yellow" cx="200" cy="200" r="100" />
  <rect fill="none" stroke="black" stroke-width="12" x="0" y="0" width="400" height="400" />
  <text size="30" x="160" y="210">
    Hello world
    <animateTransform attributeName="transform" from="0 200 200" to="360 200 200" type="rotate" dur="5" repeatCount="indefinite" />
  </text>
</svg>

Parsing SVG text into a minisvg document

minisvg uses xml2 to parse SVGL text (or file) into a minisvg document.

my_svg <- "<svg><circle cx='10' cy='10' r='5'/></svg>"
doc <- minisvg::parse_svg_doc(my_svg)
doc$update(fill = "none")$
  add(name = 'rect')

print(doc)
<?xml version="1.0" encoding="UTF-8"?>
<svg width="400" height="400" viewBox="0 0 400 400" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" fill="none">
  <circle cx="10" cy="10" r="5" />
  <rect />
</svg>

70s wallpaper is my jam!

This is a reproduction of a 70s wallpaper pattern.

This example demonstrates:

  • Using svg_doc() as an alternative to SVGDocument$new()
  • Creating a <defs><pattern> object and applying it to a rectangle
doc <- svg_doc(width = 800, height = 800) 
doc$rect(x=0, y=0, width="100%", height="100%", fill='#9B8A54')

pat  <- stag$defs()$pattern(id = 'motif', width=400, height=400, patternUnits = 'userSpaceOnUse')
patg <- pat$g()

patg$circle(cx=  0, cy=  0, r=138, fill= 'white')
patg$circle(cx=  0, cy=400, r=138, fill= 'white')
patg$circle(cx=400, cy=  0, r=138, fill= 'white')
patg$circle(cx=400, cy=400, r=138, fill= 'white')
patg$circle(cx=200, cy=200, r=138, fill= 'white')

patg$circle(cx=  0, cy=  0, r=90, fill= 'none', stroke = '#4a3322', stroke_width=35)
patg$circle(cx=  0, cy=400, r=90, fill= 'none', stroke = '#4a3322', stroke_width=35)
patg$circle(cx=400, cy=  0, r=90, fill= 'none', stroke = '#4a3322', stroke_width=35)
patg$circle(cx=400, cy=400, r=90, fill= 'none', stroke = '#4a3322', stroke_width=35)
patg$circle(cx=200, cy=200, r=90, fill= 'none', stroke = '#4a3322', stroke_width=35)

patg$circle(cx=200, cy=  0, r=90, fill= 'none', stroke = '#4a3322', stroke_width=10)
patg$circle(cx=  0, cy=200, r=90, fill= 'none', stroke = '#4a3322', stroke_width=10)
patg$circle(cx=400, cy=200, r=90, fill= 'none', stroke = '#4a3322', stroke_width=10)
patg$circle(cx=200, cy=400, r=90, fill= 'none', stroke = '#4a3322', stroke_width=10)

doc$append(pat)

doc$rect(x=0, y=0, width="100%", height="100%", fill=pat) 
<?xml version="1.0" encoding="UTF-8"?>
<svg width="800" height="800" viewBox="0 0 800 800" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
  <rect fill="#9B8A54" x="0" y="0" width="100%" height="100%" />
  <pattern id="motif" width="400" height="400" patternUnits="userSpaceOnUse">
    <g>
      <circle fill="white" cx="0" cy="0" r="138" />
      <circle fill="white" cx="0" cy="400" r="138" />
      <circle fill="white" cx="400" cy="0" r="138" />
      <circle fill="white" cx="400" cy="400" r="138" />
      <circle fill="white" cx="200" cy="200" r="138" />
      <circle fill="none" stroke="#4a3322" stroke-width="35" cx="0" cy="0" r="90" />
      <circle fill="none" stroke="#4a3322" stroke-width="35" cx="0" cy="400" r="90" />
      <circle fill="none" stroke="#4a3322" stroke-width="35" cx="400" cy="0" r="90" />
      <circle fill="none" stroke="#4a3322" stroke-width="35" cx="400" cy="400" r="90" />
      <circle fill="none" stroke="#4a3322" stroke-width="35" cx="200" cy="200" r="90" />
      <circle fill="none" stroke="#4a3322" stroke-width="10" cx="200" cy="0" r="90" />
      <circle fill="none" stroke="#4a3322" stroke-width="10" cx="0" cy="200" r="90" />
      <circle fill="none" stroke="#4a3322" stroke-width="10" cx="400" cy="200" r="90" />
      <circle fill="none" stroke="#4a3322" stroke-width="10" cx="200" cy="400" r="90" />
    </g>
  </pattern>
  <rect fill="url('#motif')" x="0" y="0" width="100%" height="100%" />
</svg>

References