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

Create presentation quality SVG line graphs easily

Synopsis

  require 'SVG/Graph/Line'

  fields = %w(Jan Feb Mar);
  data_sales_02 = [12, 45, 21]
  data_sales_03 = [15, 30, 40]

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

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

  graph.add_data({
          :data => data_sales_03,
    :title => 'Sales 2003',
  })

  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 line 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, data elements at each point, title, subtitle etc.

Examples

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

Notes

The default stylesheet handles upto 10 data sets, if you use more you must create your own stylesheet and add the additional settings for the extra data sets. You will know if you go over 10 data sets as they will have no style and be in black.

See also

Author

Sean E. Russell <serATgermaneHYPHENsoftwareDOTcom>

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

Methods

Attributes

area_fill  [RW]  Fill in the area under the plot if true
show_data_points  [RW]  Show a small circle on the graph where the line goes from one point to the next.
stacked  [RW] 
 Accumulates each data set. (i.e. Each point increased by sum of
all previous series at same point). Default is 0, set to ‘1’ to show.

Public Class methods

The constructor takes a hash reference, fields (the names for each field on the X axis) MUST be set, all other values are defaulted to those shown above - with the exception of style_sheet which defaults to using the internal style sheet.

[Source]

    # File lib/SVG/Graph/Line.rb, line 85
85:         def initialize config
86:             raise "fields was not supplied or is empty" unless config[:fields] &&
87:             config[:fields].kind_of?(Array) &&
88:             config[:fields].length > 0
89:             super
90:         end

Public Instance methods

In addition to the defaults set in Graph::initialize, sets

show_data_points
true
show_data_values
true
stacked
false
area_fill
false

[Source]

     # File lib/SVG/Graph/Line.rb, line 97
 97:         def set_defaults
 98:         init_with(
 99:         :show_data_points   => true,
100:         :show_data_values   => true,
101:         :stacked            => false,
102:         :area_fill          => false
103:         )
104:         
105: 
106:         self.top_align = self.top_font = self.right_align = self.right_font = 1
107:         end

Protected Instance methods

[Source]

     # File lib/SVG/Graph/Line.rb, line 175
175:       def calc_coords(field, value, width = field_width, height = field_height)
176:         coords = {:x => 0, :y => 0}
177:         coords[:x] = width * field
178:         coords[:y] = @graph_height - value * height
179:       
180:         return coords
181:       end

[Source]

     # File lib/SVG/Graph/Line.rb, line 149
149:       def calculate_left_margin
150:         super
151:         label_left = @config[:fields][0].length / 2 * font_size * 0.6
152:         @border_left = label_left if label_left > @border_left
153:       end

[Source]

     # File lib/SVG/Graph/Line.rb, line 183
183:       def draw_data
184:         minvalue = min_value
185:         fieldheight = (@graph_height.to_f - font_size*2*top_font) / 
186:                          (get_y_labels.max - get_y_labels.min)
187:         fieldwidth = field_width
188:         line = @data.length
189: 
190:         prev_sum = Array.new(@config[:fields].length).fill(0)
191:         cum_sum = Array.new(@config[:fields].length).fill(-minvalue)
192: 
193:         for data in @data.reverse
194:           lpath = ""
195:           apath = ""
196: 
197:           if not stacked then cum_sum.fill(-minvalue) end
198:           
199:           data[:data].each_index do |i|
200:             cum_sum[i] += data[:data][i]
201:             
202:             c = calc_coords(i, cum_sum[i], fieldwidth, fieldheight)
203:             
204:             lpath << "#{c[:x]} #{c[:y]} "
205:           end
206:         
207:           if area_fill
208:             if stacked then
209:               (prev_sum.length - 1).downto 0 do |i|
210:                 c = calc_coords(i, prev_sum[i], fieldwidth, fieldheight)
211:                 
212:                 apath << "#{c[:x]} #{c[:y]} "
213:               end
214:           
215:               c = calc_coords(0, prev_sum[0], fieldwidth, fieldheight)
216:             else
217:               apath = "V#@graph_height"
218:               c = calc_coords(0, 0, fieldwidth, fieldheight)
219:             end
220:               
221:             @graph.add_element("path", {
222:               "d" => "M#{c[:x]} #{c[:y]} L" + lpath + apath + "Z",
223:               "class" => "fill#{line}"
224:             })
225:           end
226:         
227:           @graph.add_element("path", {
228:             "d" => "M0 #@graph_height L" + lpath,
229:             "class" => "line#{line}"
230:           })
231:           
232:           if show_data_points || show_data_values
233:             cum_sum.each_index do |i|
234:               if show_data_points
235:                 @graph.add_element( "circle", {
236:                   "cx" => (fieldwidth * i).to_s,
237:                   "cy" => (@graph_height - cum_sum[i] * fieldheight).to_s,
238:                   "r" => "2.5",
239:                   "class" => "dataPoint#{line}"
240:                 })
241:               end
242:               make_datapoint_text( 
243:                 fieldwidth * i, 
244:                 @graph_height - cum_sum[i] * fieldheight - 6,
245:                 cum_sum[i] + minvalue
246:               )
247:             end
248:           end
249: 
250:           prev_sum = cum_sum.dup
251:           line -= 1
252:         end
253:       end

[Source]

     # File lib/SVG/Graph/Line.rb, line 256
256:       def get_css
257:         return "/* default line styles */\n.line1{\n        fill: none;\n        stroke: #ff0000;\n        stroke-width: 1px;     \n}\n.line2{\n        fill: none;\n        stroke: #0000ff;\n        stroke-width: 1px;     \n}\n.line3{\n        fill: none;\n        stroke: #00ff00;\n        stroke-width: 1px;     \n}\n.line4{\n        fill: none;\n        stroke: #ffcc00;\n        stroke-width: 1px;     \n}\n.line5{\n        fill: none;\n        stroke: #00ccff;\n        stroke-width: 1px;     \n}\n.line6{\n        fill: none;\n        stroke: #ff00ff;\n        stroke-width: 1px;     \n}\n.line7{\n        fill: none;\n        stroke: #00ffff;\n        stroke-width: 1px;     \n}\n.line8{\n        fill: none;\n        stroke: #ffff00;\n        stroke-width: 1px;     \n}\n.line9{\n        fill: none;\n        stroke: #ccc6666;\n        stroke-width: 1px;     \n}\n.line10{\n        fill: none;\n        stroke: #663399;\n        stroke-width: 1px;     \n}\n.line11{\n        fill: none;\n        stroke: #339900;\n        stroke-width: 1px;     \n}\n.line12{\n        fill: none;\n        stroke: #9966FF;\n        stroke-width: 1px;     \n}\n/* default fill styles */\n.fill1{\n        fill: #cc0000;\n        fill-opacity: 0.2;\n        stroke: none;\n}\n.fill2{\n        fill: #0000cc;\n        fill-opacity: 0.2;\n        stroke: none;\n}\n.fill3{\n        fill: #00cc00;\n        fill-opacity: 0.2;\n        stroke: none;\n}\n.fill4{\n        fill: #ffcc00;\n        fill-opacity: 0.2;\n        stroke: none;\n}\n.fill5{\n        fill: #00ccff;\n        fill-opacity: 0.2;\n        stroke: none;\n}\n.fill6{\n        fill: #ff00ff;\n        fill-opacity: 0.2;\n        stroke: none;\n}\n.fill7{\n        fill: #00ffff;\n        fill-opacity: 0.2;\n        stroke: none;\n}\n.fill8{\n        fill: #ffff00;\n        fill-opacity: 0.2;\n        stroke: none;\n}\n.fill9{\n        fill: #cc6666;\n        fill-opacity: 0.2;\n        stroke: none;\n}\n.fill10{\n        fill: #663399;\n        fill-opacity: 0.2;\n        stroke: none;\n}\n.fill11{\n        fill: #339900;\n        fill-opacity: 0.2;\n        stroke: none;\n}\n.fill12{\n        fill: #9966FF;\n        fill-opacity: 0.2;\n        stroke: none;\n}\n/* default line styles */\n.key1,.dataPoint1{\n        fill: #ff0000;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key2,.dataPoint2{\n        fill: #0000ff;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key3,.dataPoint3{\n        fill: #00ff00;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key4,.dataPoint4{\n        fill: #ffcc00;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key5,.dataPoint5{\n        fill: #00ccff;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key6,.dataPoint6{\n        fill: #ff00ff;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key7,.dataPoint7{\n        fill: #00ffff;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key8,.dataPoint8{\n        fill: #ffff00;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key9,.dataPoint9{\n        fill: #cc6666;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key10,.dataPoint10{\n        fill: #663399;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key11,.dataPoint11{\n        fill: #339900;\n        stroke: none;\n        stroke-width: 1px;     \n}\n.key12,.dataPoint12{\n        fill: #9966FF;\n        stroke: none;\n        stroke-width: 1px;     \n}\n"
258:       end

[Source]

     # File lib/SVG/Graph/Line.rb, line 145
145:       def get_x_labels
146:         @config[:fields]
147:       end

[Source]

     # File lib/SVG/Graph/Line.rb, line 155
155:       def get_y_labels
156:         maxvalue = max_value
157:         minvalue = min_value
158:         range = maxvalue - minvalue
159:         top_pad = range == 0 ? 10 : range / 20.0
160:         scale_range = (maxvalue + top_pad) - minvalue
161: 
162:         scale_division = scale_divisions || (scale_range / 10.0)
163: 
164:         if scale_integers
165:           scale_division = scale_division < 1 ? 1 : scale_division.round
166:         end
167: 
168:         rv = []
169:         maxvalue = maxvalue%scale_division == 0 ? 
170:           maxvalue : maxvalue + scale_division
171:         minvalue.step( maxvalue, scale_division ) {|v| rv << v}
172:         return rv
173:       end

[Source]

     # File lib/SVG/Graph/Line.rb, line 111
111:         def max_value
112:             max = 0
113:             
114:             if (stacked == true) then
115:               sums = Array.new(@config[:fields].length).fill(0)
116:             
117:               @data.each do |data|
118:                 sums.each_index do |i|
119:                   sums[i] += data[:data][i].to_f
120:                 end
121:               end
122:               
123:               max = sums.max
124:             else
125:               max = @data.collect{|x| x[:data].max}.max
126:             end
127:             
128:             return max
129:         end

[Source]

     # File lib/SVG/Graph/Line.rb, line 131
131:       def min_value
132:         min = 0
133:         
134:         if (min_scale_value.nil? == false) then
135:           min = min_scale_value
136:         elsif (stacked == true) then
137:           min = @data[-1][:data].min
138:         else
139:           min = @data.collect{|x| x[:data].min}.min
140:         end
141: 
142:         return min
143:       end

[Validate]