tagcloud (version 0.1)

tagcloud: Generate a tag / word cloud plot

Description

Functions to create and display plots called tag clouds, word clouds or weighted lists, in which a usually large number of words is displayed in size correlated with a numerical value (for example, frequency in a text or enrichment of a GO term). This makes it easier to visualize the prominence of certain tags or words. Also, it looks kind of nice.

Usage

tagcloud( tags, weights = 1, 
          algorithm = "oval", scale = "auto", 
          order = "size", sel= NULL,
          wmin = NULL, wmax = NULL, floor = 1, ceiling = 3, 
          family = NULL, col = NULL, fvert = 0, 
          plot = TRUE, add = FALSE)
## S3 method for class 'tagcloud':
plot( x, family = NULL, add = FALSE, with.box = FALSE, col = NULL, \dots )
## S3 method for class 'tagcloud':
summary( object, ... )
## S3 method for class 'tagcloud':
print( x, ... )

Arguments

tags

A character vector containing words or tags to be shown on the plot.

weights

A numeric vector giving the relative proportions of text size corresponding to the given tag.

x,object

An object of the type produced by tagcloud.

...

Further arguments to be passed to downstream methods.

algorithm

Name of the algorithm to use. Can be "oval", "fill", "random" or "list". See Details.

scale

If "auto", text expansion will be calculated automatically to fit the available space. Otherwise, a numeric value used to modify the calculated text sizes; tune scale to achieve a better fit.

order

Determines in which order the tags will be drawn. Can be "size", "keep", "random", "height" or "width". See Details.

sel

An integer or boolean vector indicating which terms from the provided list will be used to plot. The vectors col and weights will be filtered accordingly.

wmin

All items in the weights vector smaller than wmin will be changed to wmin

wmax

All items in the weights vector larger than wmax will be changed to wmax

floor

Minimal text size. See Details.

ceiling

Maximal text size. See Details.

family

Font family to use, a vector containing font families to use for each tag. For the tagcloud function, the special keyword "random" can be used to assign random families.

col

Color or a vector containing colors to use for drawing the tags.

fvert

Fraction of tags which will be rotated by 90 degrees counterclockwise.

plot

If FALSE, no plot will be produced.

add

If TRUE, the tags will be added to the current plot instead of creating a new plot.

with.box

If TRUE, a rectangle will be plotted around each tag.

Value

• tagcloud returns an object of the tagcloud-class, which really is a data frame with the following columns:
  • tags
  { -- the tags, words or phrases shown on the plot}

• weights
  -- a numeric vector that is used to calculate the size of the plotted tags
• family
  -- name of the font family to be used in plotting
• vertical
  -- whether the tag should be rotated by 90 degrees counter-clockwise
• x,y
  -- coordinates of the left lower corner of the tags bounding box
• w,h
  -- width and height of the bounding box
• cex
  -- text expansion factor, see par
• s
  -- surface of the tag (width x height)

subsection

• Algorithms
• Calculation of tag sizes

itemize

• oval

item

• fill
• random
• list
• clist

code

summary

Details

The package tagcloud creates and plots tag clouds (word clouds). The algorithms in the package have been designed specifically with long tags (such as GO Term descriptions) in mind.

Term ordering{ The available arguments are as follows:

• size

{ -- tags are ordered by size, that is, their effective width multiplied by their effective height. Default.} keep{ -- keep the order from the list of words provided} random{ -- randomize the tag list} width{ -- order by effective screen width} height{ -- order by effective screen height} }

By default, prior to plotting terms are ordered by size.

See Also

editor.tagcloud -- interactive editing of tagcloud objects.

strmultline -- splitting multi-word sentences into lines for a better cloud display.

smoothPalette -- mapping values onto a color gradient.

Examples

# a rather boring tag cloud
data( gambia )
terms <- gambia$Term
tagcloud( terms )

# tag cloud with weights relative to P value
# colors relative to odds ratio, from light
# grey to black
weights <- -log( gambia$Pvalue )
colors  <- smoothPalette( gambia$OddsRatio, max=4 )
tagcloud( terms, weights, col= colors, algorithm= "oval" )

# tag cloud filling the whole plot
tagcloud( terms, weights, col= colors, algorithm= "fill" )

# just a list of only the first ten terms
tagcloud( terms, weights, sel= 1:10,
          col= colors, algorithm= "list", order= "width" )

# oval, with line breaks in terms
terms <- strmultline( gambia$Term )
tagcloud( terms, weights, col= colors, algorithm= "oval" )

# shows available font families, scaled according to
# the total disk space occupied by the fonts
require( extrafont )
ft <- fonttable()
fi <- file.info( fonttable()$fontfile )
families <- unique( ft$FamilyName )
sizes    <- sapply( families,function( x ) sum( fi[ ft$FamilyName == x, "size" ] ) )
tagcloud( families, sizes, family= families )