Warren Seen

The version I posted yesterday had a dodgy tag cloud implementation that I was experimenting with. I’ve reworked it this morning between other tasks and am much happier now. I imported some delicious bookmarks to populate the db a bit more and the result is this:

Much better!

Initially, the tag cloud was overpowered by one tag because I was using a linear weighting, but once I switched to using a logarithmic weighting, things looked a lot better.

This is how the tag cloud is rendered, using Markaby:

# Render the tag cloud view
def tag_cloud(tags = nil)
  @tags ||= tags
  max = 0
  @tags.each do |t|
    max = t.taggings.length if t.taggings.length > max
  end

  div.cloud do
    @tags.each do |t|
      weight = Math.log10(t.taggings.length) / Math.log10(max.to_f)
      _cloud_tag(t, weight)
    end
  end
end

# Generate tag HTML
def _tag(name, style = nil)
  a.tag(name, :href => R(Tags, name), :title => "All entries tagged '#{name}'", :style => style)
end

# Generate the HTML for the tag in the cloud
def _cloud_tag(tag,weight)
  _tag(tag.name,style_for_weight(weight))
  self << " "
end

# Generate a CSS style string
def style_for_weight(weight)
  n = 0xff/2 + (0xff/2*weight).to_i
  "font-size:#{0.5 + weight}em;color:rgb(#{n},#{n},#{n})"
end

This entry was posted on Monday, April 2nd, 2007 at 5:26 pm and is filed under camping, programming, ruby. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.