Reusable Graphics

Overview

How can we make reusable graphics?

What can we do with reusable graphics?

What does "reusable graphics" mean?

Reusing Raster Images

R -> PNG

png("xyplot.png")
xyplot(mpg ~ disp, mtcars)
dev.off()

Reusing Raster Images

PNG -> R

library(png)
map <- readPNG("map.png")
plot(data)
rasterImage(map)

Reusing Vector Images

R -> PDF

pdf("xyplot.pdf")
xyplot(mpg ~ disp, mtcars)
dev.off()

Reusing Vector Images

PostScript -> R

library(grImport)
PostScriptTrace("chess_game.eps", 
                "chess_game.xml")
chess <- readPicture("chess_game.xml")
pawn <- chess[119]
xyplot(..., 
       panel=function(...) {
                 grid.symbols(pawn, ...)
             })

Reusing Marked Up Images

R -> R

library(grid)
library(lattice)
xyplot(mpg ~ disp, mtcars)

Reusing Marked Up Images

xyplot(mpg ~ disp, mtcars)
grid.ls()

viewport[ROOT]
  rect[plot_01.background]
  viewport[plot_01.toplevel.vp]
    viewport[plot_01.xlab.vp]
      text[plot_01.xlab]
    viewport[plot_01.ylab.vp]
      text[plot_01.ylab]

Reusing Marked Up Images

xyplot(mpg ~ disp, mtcars)
grid.edit("plot_01.ylab", rot=0)

Reusing Marked Up Images

R -> SVG

library(gridSVG)
xyplot(mpg ~ disp, mtcars)
grid.export("svg-plot.svg")

Reusing Marked Up Images

<svg>
  <rect id="plot_01.background.1.1"/>
  <g id="plot_01.toplevel.vp.1">
    <g id="plot_01.xlab.vp.1">
      <text id="plot_01.xlab.1">
        disp
      </text>
...

Reusing Marked Up Images

xyplot(mpg ~ disp, mtcars)
grid.garnish("plot_01.xyplot.points.panel.1.1", 
             title=rownames(mtcars))
grid.export("svg-plot.svg")

Reusing Marked Up Images

SVG -> R

library(XML)
svg <- xmlParse("Multilingualism.svg")
polys <- getNodeSet(svg, "//svg:polygon")
invisible(lapply(polys[!retain], remove))
saveXML(svg, "Multilingualism-Auckland.svg")

Licencing

It is important to remember to provide permission for others to use your graphic

versus ©

Summary

Reusable graphics are better than dead-end graphics

Choosing the right format is important
- Vector is better than raster

Adding mark up (labels and structure) is also important
- SVG is better than PDF

Acknowledgements

The NASA light data is from Steve Mosher
The Google Map tile is copyright 2011 Google, Map Data and copyright 2011 Tele Atlas.
The chess board image (by Jose Hevia) is from the Open Clip Art Library
Chess ranking data are from the FIDE Top 100 Players for June 2013
The map of Multilingualism in New Zealand was created by Paul Behrens for the Royal Society of New Zealand
R packages: grid, lattice, png, grImport, gridSVG, and XML
Slides based on Paul Rouget's dzslides template and built using Yihui Xie's knitr package
Google Web Fonts: Droid Sans, Inconsolata, and Special Elite