GChart

github.com/jbarnette/gchart

Description

GChart exposes the Google Chart API via a friendly Ruby interface. It can generate the URL for a given chart (for webpage use), or download the generated PNG (for offline use).

Simple Examples

# line chart
g = GChart.line :data => [0, 10, 100]

# bar chart
g = GChart.bar :data => [100, 1000, 10000]

# pie chart (pie3d for a fancier look)
g = GChart.pie :data => [33, 33, 34]

# venn diagram (asize, bsize, csize, ab%, bc%, ca%, abc%)
g = GChart.venn :data => [100, 80, 60, 30, 30, 30, 10]

# scatter plot (x coords, y coords [, sizes])
g = GChart.scatter(
      :data => [[1, 2, 3, 4, 5], [5, 4, 3, 2, 1], [1, 2, 3, 4, 5]])

# map chart
g = GChart.map :area => 'usa', :data => { 'NY' => 1, 'VA' => 3, 'CA' => 2 }

# meter
g = GChart.meter :data => 70, :label => "70%"

# chart title
g = GChart.line :title => "Awesomeness over Time", :data => [0, 10, 100]

# data set legend
g = GChart.line :data   => [[1, 2], [3, 4]],
                :legend => ["Monkeys", "Ferrets"]

# data set colors
g = GChart.line :data   => [[0, 10, 100], [100, 10, 0]],
                :colors => ["ff0000", "0000ff"]

g.to_url            # generate the chart's URL, or
g.fetch             # get the bytes, or
g.write "foo.png"   # write to a file (defaults to "chart.png")
g.write stream      # write to anything that quacks like IO

Detailed Examples

Simple Line Chart with 2 data sets

chart = GChart.line do |g|
  g.data   = [[0, 1, 2, 3, 4, 5, 6], [3, 2, 4, 1, 5, 0, 6]]
  g.colors = [:red,                  :yellow]
  g.legend = ["Line",                "Wonkiness"]

  g.width             = 600
  g.height            = 150
  g.entire_background = "f4f4f4"

  g.axis(:left) { |a| a.range = 0..6 }

  g.axis :bottom do |a|
    a.labels          = ["Mon", "Tue", "Thu", "Sun"]
    a.label_positions = [0,     16.67, 50,    100]
    a.text_color      = :black
  end

  g.axis :bottom do |a|
    a.labels          = ["Week 42"]
    a.label_positions = [50]
  end
end

Complex Line Chart with multiple axes

chart = GChart.line do |g|
  g.data   = [data_array1, data_array2, data_array3]
  g.colors = [:red,        :green,      :blue]
  g.legend = ["Set 1",     "Set 2",     "Set 3"]

  g.width  = 950
  g.height = 315

  g.entire_background = "434"
  g.chart_background  = "aba"

  g.axis(:left) do |a|
    a.range      = 0..100
    a.text_color = :red
    a.font_size  = 9
  end

  g.axis(:right) do |a|
    a.font_size       = 8
    a.label_positions = [250, 500, 750]
    a.labels          = %w(250 500 750)
    a.range           = 0..1000
    a.text_alignment  = :right
    a.text_color      = :green
  end

  g.axis(:top) do |a|
    a.labels    = %w(2008)
    a.positions = [50]
  end

  bottom1        = g.axis :bottom
  bottom1.labels = dates_array

  bottom1.range_markers = [
    [0..33.33,     'ff000044'],
    [33.33..66.67, '00ff0044'],
    [66.67..100,   '0000ff44']
  ]

  # We "manually" create our 2nd bottom axis...

  bottom2                 = GChart::Axis.create :bottom
  bottom2.labels          = %w(Dates)
  bottom2.label_positions = [50]

  # ...and therefore need to also add it to our axes "manually".
  g.axes << bottom2
end

url = chart.to_url

Axis Labeling

Charts which support an axis concept can be labeled. Supported types are line charts, bar charts, radar charts and scatter plots. See GChart::Axis for more information.

TODO

Add grid lines, linear stripes, shape markers, gradient fills
Make venn data specification friendlier
Make documentation more digestible

There are lots of missing features. Until they’re implemented, you can directly specify query parameters using the :extras key, e.g.,

# provides a legend for each data set
g = GChart.line :data   => [[1, 2], [3, 4]],
                :extras => { "chdl" => "First|Second" }

License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the ‘Software’), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED ‘AS IS’, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.