Class: GoogleChart::Base

Inherits:
Object
  • Object
show all
Defined in:
lib/google_chart/base.rb

Direct Known Subclasses

BarChart, LineChart, PieChart, VennDiagram

Constant Summary collapse

BASE_URL = 
"http://chart.apis.google.com/chart?"
SIMPLE_ENCODING = 
'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'.split('')
COMPLEX_ENCODING_ALPHABET = 
'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-.'.split('')
@@complex_encoding = 
[]

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(chart_size, chart_title) ⇒ Base

Returns a new instance of Base.



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# File 'lib/google_chart/base.rb', line 18

def initialize(chart_size, chart_title)
    self.params = Hash.new
    @labels = []
    @data   = []
    @colors = []
    @axis   = []
    self.chart_size    = chart_size
    self.chart_title   = chart_title
    self.data_encoding = :simple
    self.show_legend   = true
    self.show_labels   = false
end

Instance Attribute Details

#chart_size ⇒ Object

Returns the value of attribute chart_size.



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# File 'lib/google_chart/base.rb', line 16

def chart_size
  @chart_size
end

#chart_title ⇒ Object

Returns the value of attribute chart_title.



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# File 'lib/google_chart/base.rb', line 16

def chart_title
  @chart_title
end

#chart_type ⇒ Object

Returns the value of attribute chart_type.



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# File 'lib/google_chart/base.rb', line 16

def chart_type
  @chart_type
end

#data_encoding ⇒ Object

Returns the value of attribute data_encoding.



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# File 'lib/google_chart/base.rb', line 16

def data_encoding
  @data_encoding
end

#params ⇒ Object

Returns the value of attribute params.



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# File 'lib/google_chart/base.rb', line 16

def params
  @params
end

#show_labels ⇒ Object

Returns the value of attribute show_labels.



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# File 'lib/google_chart/base.rb', line 16

def show_labels
  @show_labels
end

#show_legend ⇒ Object

Returns the value of attribute show_legend.



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# File 'lib/google_chart/base.rb', line 16

def show_legend
  @show_legend
end

Instance Method Details

#axis(type, options = {}) ⇒ Object

Adds an axis to the graph. Not applicable for Pie Chart (GoogleChart::PieChart) or Venn Diagram (GoogleChart::VennDiagram)

type

is a symbol which can be one of :x, :y, :right, :top

options

is a hash containing the options (see below)

Options

Not all the options are mandatory.

:labels

An array containing the labels for the axis

:position

An Array containing the positions for the labels

:range

An array containing 2 elements, the start value and end value

axis styling options have to be specified as follows

:color

Hexadecimal RGB value for the color to represent the data for the axis labels

:font_size

Font size of the labels in pixels

:alignment

can be one of :left, :center or :right

Examples

lc.axis :y, :range => [0,6], :color => 'ff00ff', :font_size => 16, :alignment => :center



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# File 'lib/google_chart/base.rb', line 125

def axis(type, options = {})
  raise "Illegal axis type" unless [:x, :y, :right, :top].member?(type)          
  @axis << [type, options]
end

#data(name, value, color = nil) ⇒ Object

Adds the data to the chart, according to the type of the graph being generated.

name

is a string containing a label for the data.

value

is either a number or an array of numbers containing the data. Pie Charts and Venn Diagrams take a single number, but other graphs require an array of numbers

color (optional)

is a hexadecimal RGB value for the color to represent the data

Examples

for GoogleChart::LineChart (normal)

lc.data "Trend 1", [1,2,3,4,5], 'ff00ff'

for GoogleChart::LineChart (XY chart)

lc.data "Trend 2", [[4,5], [2,2], [1,1], [3,4]], 'ff00ff'

for GoogleChart::PieChart

lc.data "Apples", 5, 'ff00ff'
lc.data "Oranges", 7, '00ffff'



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# File 'lib/google_chart/base.rb', line 75

def data(name, value, color=nil)
    @data << value
    @labels << name
    @colors << color if color
end

#fill(bg_or_c, type, options = {}) ⇒ Object

Adds a background or chart fill. Call this option twice if you want both a background and a chart fill

bg_or_c

Can be one of :background or :chart depending on the kind of fill requested

type

Can be one of :solid, :gradient or :stripes

options

: Options depend on the type of fill selected above

Options

For :solid type

  • A :color option which specifies the RGB hex value of the color to be used as a fill. For e.g lc.fill(:chart, :solid, {:color => 'ffcccc'})

For :gradient type

  • An <tt>:angle</p>, which is the angle of the gradient between 0(horizontal) and 90(vertical)

  • A :color option which is a 2D array containing the colors and an offset each, which specifies at what point the color is pure where: 0 specifies the right-most chart position and 1 the left-most. e,g lc.fill :background, :gradient, :angle => 0, :color => [['76A4FB',1],['ffffff',0]]

For :stripes type

  • An <tt>:angle</p>, which is the angle of the stripe between 0(horizontal) and 90(vertical)

  • A :color option which is a 2D array containing the colors and width value each, which must be between 0 and 1 where 1 is the full width of the chart. for e.g lc.fill :chart, :stripes, :angle => 90, :color => [ ['76A4FB',0.2], ['ffffff',0.2] ]



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# File 'lib/google_chart/base.rb', line 97

def fill(bg_or_c, type, options = {})
    case bg_or_c
        when :background
            @background_fill = "bg," + process_fill_options(type, options)
        when :chart
            @chart_fill = "c," + process_fill_options(type, options)
    end
end

#grid(options = {}) ⇒ Object

Adds a grid to the graph. Applicable only for Line Chart (GoogleChart::LineChart) and Scatter Chart (available soon)

options

is a hash containing the options (see below)

Options

:xstep

X axis step size

:ystep

Y axis step size

:length_segment (optional)

Length of the line segement. Useful with the :length_blank value to have dashed lines

:length_blank (optional)

Length of the blank segment. use 0 if you want a solid grid

Examples

lc.grid :x_step => 5, :y_step => 5, :length_segment => 1, :length_blank => 0



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# File 'lib/google_chart/base.rb', line 144

def grid(options={})
  @grid_str = "#{options[:x_step].to_f},#{options[:y_step].to_f}"
  if options[:length_segment] or options[:length_blank]
     @grid_str += ",#{options[:length_segment].to_f},#{options[:length_blank].to_f}"
  end
end

#to_url(extras = {}) ⇒ Object

Generates the URL string that can be used to retrieve the graph image in PNG format. Use this after assigning all the properties to the graph You can pass in additional params as a hash for features that may not have been implemented For e.g

lc = GoogleChart::LineChart.new('320x200', "Line Chart", false)
lc.data "Trend 1", [5,4,3,1,3,5,6], '0000ff'
lc.data "Trend 2", [1,2,3,4,5,6], '00ff00'
lc.data "Trend 3", [6,5,4,3,2,1], 'ff0000'
puts lc.to_url({:chm => "000000,0,0.1,0.11"}) # Single black line as a horizontal marker



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# File 'lib/google_chart/base.rb', line 40

def to_url(extras={})
    params.clear
    set_size
    set_type
    set_colors
    set_fill_options
    add_axis
    add_grid  
    add_data
    add_labels(@labels) if show_labels
    add_legend(@labels) if show_legend
    add_title  if chart_title.to_s.length > 0 
    
    params.merge!(extras)
    query_string = params.map { |k,v| "#{k}=#{URI.escape(v.to_s)}" }.join('&')
    BASE_URL + query_string
end