Class SVG::Graph::Pie
In: lib/SVG/Graph/Pie.rb
Parent: Graph

Create presentation quality SVG pie graphs easily

Synopsis

  require 'SVG/Graph/Pie'

  fields = %w(Jan Feb Mar)
  data_sales_02 = [12, 45, 21]

  graph = SVG::Graph::Pie.new({
          :height => 500,
    :width  => 300,
    :fields => fields,
  })

  graph.add_data({
          :data => data_sales_02,
    :title => 'Sales 2002',
  })

  print "Content-type: image/svg+xml\r\n\r\n"
  print graph.burn();

Description

This object aims to allow you to easily create high quality SVG pie graphs. You can either use the default style sheet or supply your own. Either way there are many options which can be configured to give you control over how the graph is generated - with or without a key, display percent on pie chart, title, subtitle etc.

Examples

www.germane-software/repositories/public/SVG/test/single.rb

See also

Author

Sean E. Russell <serATgermaneHYPHENsoftwareDOTcom>

Copyright 2004 Sean E. Russell This software is available under the Ruby license

Methods

Constants

RADIANS = Math::PI/180

Attributes

datapoint_font_size  [RW]  The font size of the data point labels
expand_gap  [RW]  The amount of space between expanded wedges
expand_greatest  [RW]  If true, expand the largest pie wedge
expanded  [RW]  If true, "explode" the pie (put space between the wedges)
shadow_offset  [RW]  Sets the offset of the shadow from the pie chart
show_actual_values  [RW]  If true, display the actual field values in the data labels
show_data_labels  [RW]  If true, display the data labels on the chart
show_key_actual_values  [RW]  If true, display the actual value of the field in the key
show_key_data_labels  [RW]  If true, display the labels in the key
show_key_percent  [RW]  If true, display the percentage value of the wedges in the key
show_percent  [RW]  If true, display the percentage value of each pie wedge in the data labels
show_shadow  [RW]  If true, displays a drop shadow for the chart

Public Instance methods

Adds a data set to the graph.

  graph.add_data( { :data => [1,2,3,4] } )

Note that the :title is not necessary. If multiple data sets are added to the graph, the pie chart will display the sums of the data. EG:

  graph.add_data( { :data => [1,2,3,4] } )
  graph.add_data( { :data => [2,3,5,9] } )

is the same as:

  graph.add_data( { :data => [3,5,8,13] } )

[Source]

     # File lib/SVG/Graph/Pie.rb, line 111
111:       def add_data arg
112:         arg[:data].each_index {|idx|
113:           @data[idx] = 0 unless @data[idx]
114:           @data[idx] += arg[:data][idx]
115:         }
116:       end

Defaults are those set by Graph::initialize, and

show_shadow
true
shadow_offset
10
show_data_labels
false
show_actual_values
false
show_percent
true
show_key_data_labels
true
show_key_actual_values
true
show_key_percent
false
expanded
false
expand_greatest
false
expand_gap
10
show_x_labels
false
show_y_labels
false
datapoint_font_size
12

[Source]

    # File lib/SVG/Graph/Pie.rb, line 73
73:       def set_defaults
74:         init_with(
75:           :show_shadow                  => true,
76:           :shadow_offset                => 10, 
77:           
78:           :show_data_labels           => false,
79:           :show_actual_values     => false,
80:           :show_percent                 => true,
81: 
82:           :show_key_data_labels   => true,
83:           :show_key_actual_values => true,
84:           :show_key_percent                 => false,
85:           
86:           :expanded                                     => false,
87:           :expand_greatest                  => false,
88:           :expand_gap             => 10,
89:           
90:           :show_x_labels          => false,
91:           :show_y_labels          => false,
92:           :datapoint_font_size    => 12
93:         )
94:         @data = []
95:       end

Protected Instance methods

[Source]

     # File lib/SVG/Graph/Pie.rb, line 147
147:       def add_defs defs
148:         gradient = defs.add_element( "filter", {
149:           "id"=>"dropshadow",
150:           "width" => "1.2",
151:           "height" => "1.2",
152:         } )
153:         gradient.add_element( "feGaussianBlur", {
154:           "stdDeviation" => "4",
155:           "result" => "blur"
156:         })
157:       end

[Source]

     # File lib/SVG/Graph/Pie.rb, line 187
187:       def draw_data
188:         @graph = @root.add_element( "g" )
189:         background = @graph.add_element("g")
190:         midground = @graph.add_element("g")
191: 
192:         diameter = @graph_height > @graph_width ? @graph_width : @graph_height
193:         diameter -= expand_gap if expanded or expand_greatest
194:         diameter -= datapoint_font_size if show_data_labels
195:         diameter -= 10 if show_shadow
196:         radius = diameter / 2.0
197: 
198:         xoff = (width - diameter) / 2
199:         yoff = (height - @border_bottom - diameter)
200:         yoff -= 10 if show_shadow
201:         @graph.attributes['transform'] = "translate( #{xoff} #{yoff} )"
202: 
203:         wedge_text_pad = 5
204:         wedge_text_pad = 20 if show_percent and show_data_labels
205: 
206:         total = 0
207:         max_value = 0
208:         @data.each {|x| 
209:           max_value = max_value < x ? x : max_value
210:           total += x 
211:         }
212:         percent_scale = 100.0 / total
213: 
214:         prev_percent = 0
215:         rad_mult = 3.6 * RADIANS
216:         @config[:fields].each_index { |count|
217:           value = @data[count]
218:           percent = percent_scale * value
219: 
220:           radians = prev_percent * rad_mult
221:           x_start = radius+(Math.sin(radians) * radius)
222:           y_start = radius-(Math.cos(radians) * radius)
223:           radians = (prev_percent+percent) * rad_mult
224:           x_end = radius+(Math.sin(radians) * radius)
225:           x_end -= 0.00001 if @data.length == 1
226:           y_end = radius-(Math.cos(radians) * radius)
227:           path = "M#{radius},#{radius} L#{x_start},#{y_start} "+
228:             "A#{radius},#{radius} "+
229:             "0, #{percent >= 50 ? '1' : '0'},1, "+
230:             "#{x_end} #{y_end} Z"
231: 
232: 
233:           wedge = @foreground.add_element( "path", {
234:             "d" => path,
235:             "class" => "fill#{count+1}"
236:           })
237: 
238:           translate = nil
239:           tx = 0
240:           ty = 0
241:           half_percent = prev_percent + percent / 2
242:           radians = half_percent * rad_mult
243: 
244:           if show_shadow
245:             shadow = background.add_element( "path", {
246:               "d" => path,
247:               "filter" => "url(#dropshadow)",
248:               "style" => "fill: #ccc; stroke: none;"
249:             })
250:             clear = midground.add_element( "path", {
251:               "d" => path,
252:               "style" => "fill: #fff; stroke: none;"
253:             })
254:           end
255: 
256:           if expanded or (expand_greatest && value == max_value)
257:             tx = (Math.sin(radians) * expand_gap)
258:             ty = -(Math.cos(radians) * expand_gap)
259:             translate = "translate( #{tx} #{ty} )"
260:             wedge.attributes["transform"] = translate
261:             clear.attributes["transform"] = translate if clear
262:           end
263: 
264:           if show_shadow
265:             shadow.attributes["transform"] = 
266:               "translate( #{tx+shadow_offset} #{ty+shadow_offset} )"
267:           end
268:           
269:           if show_data_labels and value != 0
270:             label = ""
271:             label += @config[:fields][count] if show_key_data_labels
272:             label += " ["+value.to_s+"]" if show_actual_values
273:             label += " "+percent.round.to_s+"%" if show_percent
274: 
275:             msr = Math.sin(radians)
276:             mcr = Math.cos(radians)
277:             tx = radius + (msr * radius)
278:             ty = radius - (mcr * radius)
279: 
280:             if expanded or (expand_greatest && value == max_value)
281:               tx += (msr * expand_gap)
282:               ty -= (mcr * expand_gap)
283:             end
284:             @foreground.add_element( "text", {
285:               "x" => tx.to_s,
286:               "y" => ty.to_s,
287:               "class" => "dataPointLabel",
288:               "style" => "stroke: #fff; stroke-width: 2;"
289:             }).text = label.to_s
290:             @foreground.add_element( "text", {
291:               "x" => tx.to_s,
292:               "y" => ty.to_s,
293:               "class" => "dataPointLabel",
294:             }).text = label.to_s
295:           end
296: 
297:           prev_percent += percent
298:         }
299:       end

We don‘t need the graph

[Source]

     # File lib/SVG/Graph/Pie.rb, line 160
160:       def draw_graph
161:       end

[Source]

     # File lib/SVG/Graph/Pie.rb, line 308
308:       def get_css
309:         return ".dataPointLabel{\n        fill: #000000;\n        text-anchor:middle;\n        font-size: \#{datapoint_font_size}px;\n        font-family: \"Arial\", sans-serif;\n        font-weight: normal;\n}\n\n/* key - MUST match fill styles */\n.key1,.fill1{\n        fill: #ff0000;\n        fill-opacity: 0.7;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key2,.fill2{\n        fill: #0000ff;\n        fill-opacity: 0.7;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key3,.fill3{\n        fill-opacity: 0.7;\n        fill: #00ff00;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key4,.fill4{\n        fill-opacity: 0.7;\n        fill: #ffcc00;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key5,.fill5{\n        fill-opacity: 0.7;\n        fill: #00ccff;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key6,.fill6{\n        fill-opacity: 0.7;\n        fill: #ff00ff;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key7,.fill7{\n        fill-opacity: 0.7;\n        fill: #00ff99;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key8,.fill8{\n        fill-opacity: 0.7;\n        fill: #ffff00;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key9,.fill9{\n        fill-opacity: 0.7;\n        fill: #cc6666;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key10,.fill10{\n        fill-opacity: 0.7;\n        fill: #663399;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key11,.fill11{\n        fill-opacity: 0.7;\n        fill: #339900;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key12,.fill12{\n        fill-opacity: 0.7;\n        fill: #9966FF;\n        stroke: none;\n        stroke-width: 1px;     \n}\n"
310:       end

[Source]

     # File lib/SVG/Graph/Pie.rb, line 167
167:       def get_x_labels
168:         [""]
169:       end

[Source]

     # File lib/SVG/Graph/Pie.rb, line 163
163:       def get_y_labels
164:         [""]
165:       end

[Source]

     # File lib/SVG/Graph/Pie.rb, line 171
171:       def keys
172:         total = 0
173:         #max_value = 0
174:         @data.each {|x| total += x }
175:         percent_scale = 100.0 / total
176:         count = -1
177:         @config[:fields].collect{ |x|
178:           count += 1
179:           v = @data[count]
180:           perc = show_key_percent ? " "+(v * percent_scale).round.to_s+"%" : ""
181:           x + " [" + v.to_s + "]" + perc
182:         }
183:       end

[Source]

     # File lib/SVG/Graph/Pie.rb, line 302
302:       def round val, to
303:         up = 10**to.to_f
304:         (val * up).to_i / up
305:       end

[Validate]