Class Gruff::Base
In: lib/gruff/base.rb
Parent: Object
StackedMixin StackedBar SideStackedBar StackedArea AccumulatorBar Base Scene Pie Area PhotoBar Bullet Spider SideBar Net Bar Dot Line Pie Observable Group SideBar StandardError IncorrectNumberOfDatasetsException Magick Bar Layer BarConversion lib/gruff/stacked_area.rb lib/gruff/scene.rb lib/gruff/spider.rb lib/gruff/pie.rb lib/gruff/bullet.rb lib/gruff/area.rb lib/gruff/net.rb lib/gruff/bar_conversion.rb lib/gruff/side_bar.rb lib/gruff/bar.rb lib/gruff/line.rb lib/gruff/stacked_bar.rb lib/gruff/dot.rb lib/gruff/side_stacked_bar.rb lib/gruff/photo_bar.rb lib/gruff/base.rb lib/gruff/accumulator_bar.rb lib/gruff/mini/bar.rb lib/gruff/mini/side_bar.rb lib/gruff/mini/pie.rb Legend Mini Deprecated Gruff dot/m_17_0.png

Methods

Included Modules

Magick Deprecated

Classes and Modules

Module Gruff::Base::StackedMixin

Constants

DEBUG = false   Draw extra lines showing where the margins and text centers are
DATA_LABEL_INDEX = 0   Used for navigating the array of data to plot
DATA_VALUES_INDEX = 1
DATA_COLOR_INDEX = 2
LEGEND_MARGIN = TITLE_MARGIN = 20.0   Space around text elements. Mostly used for vertical spacing
LABEL_MARGIN = 10.0
DEFAULT_MARGIN = 20.0
DEFAULT_TARGET_WIDTH = 800
THOUSAND_SEPARATOR = ','

Attributes

additional_line_values  [RW]  Experimental
bottom_margin  [RW]  Blank space below the graph
center_labels_over_point  [RW]  Used internally for spacing.

By default, labels are centered over the point they represent.

colors  [RW]  Get or set the list of colors that will be used to draw the bars or lines.
font  [R]  Font used for titles, labels, etc. Works best if you provide the full path to the TTF font file. RMagick must be built with the Freetype libraries for this to work properly.

Tries to find Bitstream Vera (Vera.ttf) in the location specified by ENV[‘MAGICK_FONT_PATH’]. Uses default RMagick font otherwise.

The font= method below fulfills the role of the writer, so we only need a reader here.

font_color  [RW] 
has_left_labels  [RW]  Used internally for horizontal graph types.
hide_legend  [RW]  Prevent drawing of the legend
hide_line_markers  [RW]  Prevent drawing of line markers
hide_line_numbers  [RW]  Prevent drawing of line numbers
hide_title  [RW]  Prevent drawing of the title
labels  [RW]  A hash of names for the individual columns, where the key is the array index for the column this label represents.

Not all columns need to be named.

Example: 0 => 2005, 3 => 2006, 5 => 2007, 7 => 2008

left_margin  [RW]  Blank space to the left of the graph
legend_box_size  [RW]  Optionally set the size of the colored box by each item in the legend. Default is 20.0

Will be scaled down if graph is smaller than 800px wide.

legend_font_size  [RW]  Optionally set the size of the font. Based on an 800x600px graph. Default is 20.

Will be scaled down if graph is smaller than 800px wide.

legend_margin  [RW]  Blank space below the legend
marker_color  [RW]  The color of the auxiliary lines
marker_count  [RW]  The number of horizontal lines shown for reference
marker_font_size  [RW]  The font size of the labels around the graph
maximum_value  [RW]  You can manually set a maximum value, such as a percentage-based graph that always goes to 100.

If you use this, you must set it after you have given all your data to the graph object.

minimum_value  [RW]  You can manually set a minimum value instead of having the values guessed for you.

Set it after you have given all your data to the graph object.

no_data_message  [RW]  Message shown when there is no data. Fits up to 20 characters. Defaults to "No Data."
right_margin  [RW]  Blank space to the right of the graph
sort  [RW]  Set to false if you don‘t want the data to be sorted with largest avg values at the back.
stacked  [RW]  Experimental
title  [RW]  The large title of the graph displayed at the top
title_font_size  [RW]  The font size of the large title at the top of the graph
title_margin  [RW]  Blank space below the title
top_margin  [RW]  Blank space above the graph
x_axis_label  [RW]  A label for the bottom of the graph
y_axis_increment  [RW]  Manually set increment of the horizontal marking lines
y_axis_label  [RW]  A label for the left side of the graph

Public Class methods

If one numerical argument is given, the graph is drawn at 4/3 ratio according to the given width (800 results in 800x600, 400 gives 400x300, etc.).

Or, send a geometry string for other ratios (‘800x400’, ‘400x225’).

Looks for Bitstream Vera as the default font. Expects an environment var of MAGICK_FONT_PATH to be set. (Uses RMagick‘s default font otherwise.)

[Source]

     # File lib/gruff/base.rb, line 182
182:     def initialize(target_width=DEFAULT_TARGET_WIDTH)
183:       if not Numeric === target_width
184:         geometric_width, geometric_height = target_width.split('x')
185:         @columns = geometric_width.to_f
186:         @rows = geometric_height.to_f
187:       else
188:         @columns = target_width.to_f
189:         @rows = target_width.to_f * 0.75
190:       end
191: 
192:       initialize_ivars
193: 
194:       reset_themes
195:       theme_keynote
196:     end

Public Instance methods

Add a color to the list of available colors for lines.

Example:

 add_color('#c0e9d3')

[Source]

     # File lib/gruff/base.rb, line 264
264:     def add_color(colorname)
265:       @colors << colorname
266:     end

Parameters are an array where the first element is the name of the dataset and the value is an array of values to plot.

Can be called multiple times with different datasets for a multi-valued graph.

If the color argument is nil, the next color from the default theme will be used.

NOTE: If you want to use a preset theme, you must set it before calling data().

Example:

  data("Bart S.", [95, 45, 78, 89, 88, 76], '#ffcc00')

[Source]

     # File lib/gruff/base.rb, line 457
457:     def data(name, data_points=[], color=nil)
458:       data_points = Array(data_points) # make sure it's an array
459:       @data << [name, data_points, (color || increment_color)]
460:       # Set column count if this is larger than previous counts
461:       @column_count = (data_points.length > @column_count) ? data_points.length : @column_count
462: 
463:       # Pre-normalize
464:       data_points.each_with_index do |data_point, index|
465:         next if data_point.nil?
466: 
467:         # Setup max/min so spread starts at the low end of the data points
468:         if @maximum_value.nil? && @minimum_value.nil?
469:           @maximum_value = @minimum_value = data_point
470:         end
471: 
472:         # TODO Doesn't work with stacked bar graphs
473:         # Original: @maximum_value = larger_than_max?(data_point, index) ? max(data_point, index) : @maximum_value
474:         @maximum_value = larger_than_max?(data_point) ? data_point : @maximum_value
475:         @has_data = true if @maximum_value >= 0
476: 
477:         @minimum_value = less_than_min?(data_point) ? data_point : @minimum_value
478:         @has_data = true if @minimum_value < 0
479:       end
480:     end

Sets the font for graph text to the font at font_path.

[Source]

     # File lib/gruff/base.rb, line 255
255:     def font=(font_path)
256:       @font = font_path
257:       @d.font = @font
258:     end

Set instance variables for this object.

Subclasses can override this, call super, then set values separately.

This makes it possible to set defaults in a subclass but still allow developers to change this values in their program.

[Source]

     # File lib/gruff/base.rb, line 204
204:     def initialize_ivars
205:       # Internal for calculations
206:       @raw_columns = 800.0
207:       @raw_rows = 800.0 * (@rows/@columns)
208:       @column_count = 0
209:       @marker_count = nil
210:       @maximum_value = @minimum_value = nil
211:       @has_data = false
212:       @data = Array.new
213:       @labels = Hash.new
214:       @labels_seen = Hash.new
215:       @sort = true
216:       @title = nil
217: 
218:       @scale = @columns / @raw_columns
219: 
220:       vera_font_path = File.expand_path('Vera.ttf', ENV['MAGICK_FONT_PATH'])
221:       @font = File.exists?(vera_font_path) ? vera_font_path : nil
222: 
223:       @marker_font_size = 21.0
224:       @legend_font_size = 20.0
225:       @title_font_size = 36.0
226:       
227:       @top_margin = @bottom_margin = @left_margin = @right_margin = DEFAULT_MARGIN
228:       @legend_margin = LEGEND_MARGIN
229:       @title_margin = TITLE_MARGIN
230: 
231:       @legend_box_size = 20.0
232: 
233:       @no_data_message = "No Data"
234: 
235:       @hide_line_markers = @hide_legend = @hide_title = @hide_line_numbers = false
236:       @center_labels_over_point = true
237:       @has_left_labels = false
238: 
239:       @additional_line_values = []
240:       @additional_line_colors = []
241:       @theme_options = {}
242: 
243:       @x_axis_label = @y_axis_label = nil
244:       @y_axis_increment = nil
245:       @stacked = nil
246:       @norm_data = nil
247:     end

Sets the top, bottom, left and right margins to margin.

[Source]

     # File lib/gruff/base.rb, line 250
250:     def margins=(margin)
251:       @top_margin = @left_margin = @right_margin = @bottom_margin = margin
252:     end

Replace the entire color list with a new array of colors. Also aliased as the colors= setter method.

If you specify fewer colors than the number of datasets you intend to draw, ‘increment_color’ will cycle through the array, reusing colors as needed.

Note that (as with the ‘theme’ method), you should set up your color list before you send your data (via the ‘data’ method). Calls to the ‘data’ method made prior to this call will use whatever color scheme was in place at the time data was called.

Example:

 replace_colors ['#cc99cc', '#d9e043', '#34d8a2']

[Source]

     # File lib/gruff/base.rb, line 282
282:     def replace_colors(color_list=[])
283:       @colors = color_list
284:       @color_index = 0
285:     end

You can set a theme manually. Assign a hash to this method before you send your data.

 graph.theme = {
   :colors => %w(orange purple green white red),
   :marker_color => 'blue',
   :background_colors => %w(black grey)
 }

:background_image => ‘squirrel.png’ is also possible.

(Or hopefully something better looking than that.)

[Source]

     # File lib/gruff/base.rb, line 300
300:     def theme=(options)
301:       reset_themes()
302: 
303:       defaults = {
304:         :colors => ['black', 'white'],
305:         :additional_line_colors => [],
306:         :marker_color => 'white',
307:         :font_color => 'black',
308:         :background_colors => nil,
309:         :background_image => nil
310:       }
311:       @theme_options = defaults.merge options
312: 
313:       @colors = @theme_options[:colors]
314:       @marker_color = @theme_options[:marker_color]
315:       @font_color = @theme_options[:font_color] || @marker_color
316:       @additional_line_colors = @theme_options[:additional_line_colors]
317: 
318:       render_background
319:     end

A color scheme plucked from the colors on the popular usability blog.

[Source]

     # File lib/gruff/base.rb, line 342
342:     def theme_37signals
343:       # Colors
344:       @green = '#339933'
345:       @purple = '#cc99cc'
346:       @blue = '#336699'
347:       @yellow = '#FFF804'
348:       @red = '#ff0000'
349:       @orange = '#cf5910'
350:       @black = 'black'
351:       @colors = [@yellow, @blue, @green, @red, @purple, @orange, @black]
352: 
353:       self.theme = {
354:         :colors => @colors,
355:         :marker_color => 'black',
356:         :font_color => 'black',
357:         :background_colors => ['#d1edf5', 'white']
358:       }
359:     end

A greyscale theme

[Source]

     # File lib/gruff/base.rb, line 424
424:     def theme_greyscale
425:       # Colors
426:       @colors = [
427:                  '#282828', #
428:                  '#383838', #
429:                  '#686868', #
430:                  '#989898', #
431:                  '#c8c8c8', #
432:                  '#e8e8e8', #
433:                 ]
434: 
435:       self.theme = {
436:         :colors => @colors,
437:         :marker_color => '#aea9a9', # Grey
438:         :font_color => 'black',
439:         :background_colors => 'white'
440:       }
441:     end

A color scheme similar to the popular presentation software.

[Source]

     # File lib/gruff/base.rb, line 322
322:     def theme_keynote
323:       # Colors
324:       @blue = '#6886B4'
325:       @yellow = '#FDD84E'
326:       @green = '#72AE6E'
327:       @red = '#D1695E'
328:       @purple = '#8A6EAF'
329:       @orange = '#EFAA43'
330:       @white = 'white'
331:       @colors = [@yellow, @blue, @green, @red, @purple, @orange, @white]
332: 
333:       self.theme = {
334:         :colors => @colors,
335:         :marker_color => 'white',
336:         :font_color => 'white',
337:         :background_colors => ['black', '#4a465a']
338:       }
339:     end

A color scheme similar to that used on the popular podcast site.

[Source]

     # File lib/gruff/base.rb, line 383
383:     def theme_odeo
384:       # Colors
385:       @grey = '#202020'
386:       @white = 'white'
387:       @dark_pink = '#a21764'
388:       @green = '#8ab438'
389:       @light_grey = '#999999'
390:       @dark_blue = '#3a5b87'
391:       @black = 'black'
392:       @colors = [@grey, @white, @dark_blue, @dark_pink, @green, @light_grey, @black]
393: 
394:       self.theme = {
395:         :colors => @colors,
396:         :marker_color => 'white',
397:         :font_color => 'white',
398:         :background_colors => ['#ff47a4', '#ff1f81']
399:       }
400:     end

A pastel theme

[Source]

     # File lib/gruff/base.rb, line 403
403:     def theme_pastel
404:       # Colors
405:       @colors = [
406:                  '#a9dada', # blue
407:                  '#aedaa9', # green
408:                  '#daaea9', # peach
409:                  '#dadaa9', # yellow
410:                  '#a9a9da', # dk purple
411:                  '#daaeda', # purple
412:                  '#dadada' # grey
413:                 ]
414: 
415:       self.theme = {
416:         :colors => @colors,
417:         :marker_color => '#aea9a9', # Grey
418:         :font_color => 'black',
419:         :background_colors => 'white'
420:       }
421:     end

A color scheme from the colors used on the 2005 Rails keynote presentation at RubyConf.

[Source]

     # File lib/gruff/base.rb, line 363
363:     def theme_rails_keynote
364:       # Colors
365:       @green = '#00ff00'
366:       @grey = '#333333'
367:       @orange = '#ff5d00'
368:       @red = '#f61100'
369:       @white = 'white'
370:       @light_grey = '#999999'
371:       @black = 'black'
372:       @colors = [@green, @grey, @orange, @red, @white, @light_grey, @black]
373: 
374:       self.theme = {
375:         :colors => @colors,
376:         :marker_color => 'white',
377:         :font_color => 'white',
378:         :background_colors => ['#0083a3', '#0083a3']
379:       }
380:     end

Return the graph as a rendered binary blob.

[Source]

     # File lib/gruff/base.rb, line 492
492:     def to_blob(fileformat='PNG')
493:       draw()
494:       return @base_image.to_blob do
495:         self.format = fileformat
496:       end
497:     end

Writes the graph to a file. Defaults to ‘graph.png‘

Example:

  write('graphs/my_pretty_graph.png')

[Source]

     # File lib/gruff/base.rb, line 486
486:     def write(filename="graph.png")
487:       draw()
488:       @base_image.write(filename)
489:     end

Protected Instance methods

Return a calculation of center

[Source]

     # File lib/gruff/base.rb, line 756
756:     def center(size)
757:       (@raw_columns - size) / 2
758:     end

Overridden by subclasses to do the actual plotting of the graph.

Subclasses should start by calling super() for this method.

[Source]

     # File lib/gruff/base.rb, line 506
506:     def draw
507:       make_stacked if @stacked
508:       setup_drawing
509: 
510:       debug {
511:         # Outer margin
512:         @d.rectangle( @left_margin, @top_margin,
513:                       @raw_columns - @right_margin, @raw_rows - @bottom_margin)
514:         # Graph area box
515:         @d.rectangle( @graph_left, @graph_top, @graph_right, @graph_bottom)
516:       }
517:     end

Draw the optional labels for the x axis and y axis.

[Source]

     # File lib/gruff/base.rb, line 630
630:     def draw_axis_labels
631:       unless @x_axis_label.nil?
632:         # X Axis
633:         # Centered vertically and horizontally by setting the
634:         # height to 1.0 and the width to the width of the graph.
635:         x_axis_label_y_coordinate = @graph_bottom + LABEL_MARGIN * 2 + @marker_caps_height
636: 
637:         # TODO Center between graph area
638:         @d.fill = @font_color
639:         @d.font = @font if @font
640:         @d.stroke('transparent')
641:         @d.pointsize = scale_fontsize(@marker_font_size)
642:         @d.gravity = NorthGravity
643:         @d = @d.annotate_scaled( @base_image,
644:                                  @raw_columns, 1.0,
645:                                  0.0, x_axis_label_y_coordinate,
646:                                  @x_axis_label, @scale)
647:         debug { @d.line 0.0, x_axis_label_y_coordinate, @raw_columns, x_axis_label_y_coordinate }
648:       end
649: 
650:       unless @y_axis_label.nil?
651:         # Y Axis, rotated vertically
652:         @d.rotation = 90.0
653:         @d.gravity = CenterGravity
654:         @d = @d.annotate_scaled( @base_image,
655:                                  1.0, @raw_rows,
656:                                  @left_margin + @marker_caps_height / 2.0, 0.0,
657:                                  @y_axis_label, @scale)
658:         @d.rotation = -90.0
659:       end
660:     end

Draws column labels below graph, centered over x_offset

[Source]

     # File lib/gruff/base.rb, line 857
857:     def draw_label(x_offset, index)
858:       return if @hide_line_markers
859: 
860:       if !@labels[index].nil? && @labels_seen[index].nil?
861:         y_offset = @graph_bottom + LABEL_MARGIN
862: 
863:         @d.fill = @font_color
864:         @d.font = @font if @font
865:         @d.stroke('transparent')
866:         @d.font_weight = NormalWeight
867:         @d.pointsize = scale_fontsize(@marker_font_size)
868:         @d.gravity = NorthGravity
869:         @d = @d.annotate_scaled(@base_image,
870:                                 1.0, 1.0,
871:                                 x_offset, y_offset,
872:                                 @labels[index], @scale)
873:         @labels_seen[index] = 1
874:         debug { @d.line 0.0, y_offset, @raw_columns, y_offset }
875:       end
876:     end

Draws a legend with the names of the datasets matched to the colors used to draw them.

[Source]

     # File lib/gruff/base.rb, line 764
764:     def draw_legend
765:       return if @hide_legend
766: 
767:       @legend_labels = @data.collect {|item| item[DATA_LABEL_INDEX] }
768: 
769:       legend_square_width = @legend_box_size # small square with color of this item
770: 
771:       # May fix legend drawing problem at small sizes
772:       @d.font = @font if @font
773:       @d.pointsize = @legend_font_size
774: 
775:       label_widths = [[]] # Used to calculate line wrap
776:       @legend_labels.each do |label|
777:         metrics = @d.get_type_metrics(@base_image, label.to_s)
778:         label_width = metrics.width + legend_square_width * 2.7
779:         label_widths.last.push label_width
780: 
781:         if sum(label_widths.last) > (@raw_columns * 0.9)
782:           label_widths.push [label_widths.last.pop]
783:         end
784:       end
785: 
786:       current_x_offset = center(sum(label_widths.first))
787:       current_y_offset =  @hide_title ?
788:       @top_margin + title_margin :
789:         @top_margin + title_margin + @title_caps_height
790: 
791:       @legend_labels.each_with_index do |legend_label, index|
792: 
793:         # Draw label
794:         @d.fill = @font_color
795:         @d.font = @font if @font
796:         @d.pointsize = scale_fontsize(@legend_font_size)
797:         @d.stroke('transparent')
798:         @d.font_weight = NormalWeight
799:         @d.gravity = WestGravity
800:         @d = @d.annotate_scaled( @base_image,
801:                                  @raw_columns, 1.0,
802:                                  current_x_offset + (legend_square_width * 1.7), current_y_offset,
803:                                  legend_label.to_s, @scale)
804: 
805:         # Now draw box with color of this dataset
806:         @d = @d.stroke('transparent')
807:         @d = @d.fill @data[index][DATA_COLOR_INDEX]
808:         @d = @d.rectangle(current_x_offset,
809:                           current_y_offset - legend_square_width / 2.0,
810:                           current_x_offset + legend_square_width,
811:                           current_y_offset + legend_square_width / 2.0)
812: 
813:         @d.pointsize = @legend_font_size
814:         metrics = @d.get_type_metrics(@base_image, legend_label.to_s)
815:         current_string_offset = metrics.width + (legend_square_width * 2.7)
816: 
817:         # Handle wrapping
818:         label_widths.first.shift
819:         if label_widths.first.empty?
820:           debug { @d.line 0.0, current_y_offset, @raw_columns, current_y_offset }
821: 
822:           label_widths.shift
823:           current_x_offset = center(sum(label_widths.first)) unless label_widths.empty?
824:           line_height = [@legend_caps_height, legend_square_width].max + legend_margin
825:           if label_widths.length > 0
826:             # Wrap to next line and shrink available graph dimensions
827:             current_y_offset += line_height
828:             @graph_top += line_height
829:             @graph_height = @graph_bottom - @graph_top
830:           end
831:         else
832:           current_x_offset += current_string_offset
833:         end
834:       end
835:       @color_index = 0
836:     end

Draws horizontal background lines and labels

[Source]

     # File lib/gruff/base.rb, line 663
663:     def draw_line_markers
664:       return if @hide_line_markers
665: 
666:       @d = @d.stroke_antialias false
667: 
668:       if @y_axis_increment.nil?
669:         # Try to use a number of horizontal lines that will come out even.
670:         #
671:         # TODO Do the same for larger numbers...100, 75, 50, 25
672:         if @marker_count.nil?
673:           (3..7).each do |lines|
674:             if @spread % lines == 0.0
675:               @marker_count = lines
676:               break
677:             end
678:           end
679:           @marker_count ||= 4
680:         end
681:         @increment = (@spread > 0) ? significant(@spread / @marker_count) : 1
682:       else
683:         # TODO Make this work for negative values
684:         @maximum_value = [@maximum_value.ceil, @y_axis_increment].max
685:         @minimum_value = @minimum_value.floor
686:         calculate_spread
687:         normalize(true)
688: 
689:         @marker_count = (@spread / @y_axis_increment).to_i
690:         @increment = @y_axis_increment
691:       end
692:       @increment_scaled = @graph_height.to_f / (@spread / @increment)
693: 
694:       # Draw horizontal line markers and annotate with numbers
695:       (0..@marker_count).each do |index|
696:         y = @graph_top + @graph_height - index.to_f * @increment_scaled
697: 
698:         @d = @d.fill(@marker_color)
699:         @d = @d.line(@graph_left, y, @graph_right, y)
700: 
701:         marker_label = index * @increment + @minimum_value.to_f
702: 
703:         unless @hide_line_numbers
704:           @d.fill = @font_color
705:           @d.font = @font if @font
706:           @d.stroke('transparent')
707:           @d.pointsize = scale_fontsize(@marker_font_size)
708:           @d.gravity = EastGravity
709: 
710:           # Vertically center with 1.0 for the height
711:           @d = @d.annotate_scaled( @base_image,
712:                                    @graph_left - LABEL_MARGIN, 1.0,
713:                                    0.0, y,
714:                                    label(marker_label), @scale)
715:         end
716:       end
717: 
718:       # # Submitted by a contibutor...the utility escapes me
719:       # i = 0
720:       # @additional_line_values.each do |value|
721:       #   @increment_scaled = @graph_height.to_f / (@maximum_value.to_f / value)
722:       #
723:       #   y = @graph_top + @graph_height - @increment_scaled
724:       #
725:       #   @d = @d.stroke(@additional_line_colors[i])
726:       #   @d = @d.line(@graph_left, y, @graph_right, y)
727:       #
728:       #
729:       #   @d.fill = @additional_line_colors[i]
730:       #   @d.font = @font if @font
731:       #   @d.stroke('transparent')
732:       #   @d.pointsize = scale_fontsize(@marker_font_size)
733:       #   @d.gravity = EastGravity
734:       #   @d = @d.annotate_scaled( @base_image,
735:       #                     100, 20,
736:       #                     -10, y - (@marker_font_size/2.0),
737:       #                     "", @scale)
738:       #   i += 1
739:       # end
740: 
741:       @d = @d.stroke_antialias true
742:     end

Shows an error message because you have no data.

[Source]

     # File lib/gruff/base.rb, line 879
879:     def draw_no_data
880:       @d.fill = @font_color
881:       @d.font = @font if @font
882:       @d.stroke('transparent')
883:       @d.font_weight = NormalWeight
884:       @d.pointsize = scale_fontsize(80)
885:       @d.gravity = CenterGravity
886:       @d = @d.annotate_scaled( @base_image,
887:                                @raw_columns, @raw_rows/2.0,
888:                                0, 10,
889:                                @no_data_message, @scale)
890:     end

Draws a title on the graph.

[Source]

     # File lib/gruff/base.rb, line 839
839:     def draw_title
840:       return if (@hide_title || @title.nil?)
841: 
842:       @d.fill = @font_color
843:       @d.font = @font if @font
844:       @d.stroke('transparent')
845:       @d.pointsize = scale_fontsize(@title_font_size)
846:       @d.font_weight = BoldWeight
847:       @d.gravity = NorthGravity
848:       @d = @d.annotate_scaled( @base_image,
849:                                @raw_columns, 1.0,
850:                                0, @top_margin,
851:                                @title, @scale)
852:     end

Used by StackedBar and child classes.

May need to be moved to the StackedBar class.

[Source]

      # File lib/gruff/base.rb, line 1016
1016:     def get_maximum_by_stack
1017:       # Get sum of each stack
1018:       max_hash = {}
1019:       @data.each do |data_set|
1020:         data_set[DATA_VALUES_INDEX].each_with_index do |data_point, i|
1021:           max_hash[i] = 0.0 unless max_hash[i]
1022:           max_hash[i] += data_point.to_f
1023:         end
1024:       end
1025: 
1026:       # @maximum_value = 0
1027:       max_hash.keys.each do |key|
1028:         @maximum_value = max_hash[key] if max_hash[key] > @maximum_value
1029:       end
1030:       @minimum_value = 0
1031:     end

Make copy of data with values scaled between 0-100

[Source]

     # File lib/gruff/base.rb, line 542
542:     def normalize(force=false)
543:       if @norm_data.nil? || force
544:         @norm_data = []
545:         return unless @has_data
546: 
547:         calculate_spread
548: 
549:         @data.each do |data_row|
550:           norm_data_points = []
551:           data_row[DATA_VALUES_INDEX].each do |data_point|
552:             if data_point.nil?
553:               norm_data_points << nil
554:             else
555:               norm_data_points << ((data_point.to_f - @minimum_value.to_f ) / @spread)
556:             end
557:           end
558:           @norm_data << [data_row[DATA_LABEL_INDEX], norm_data_points, data_row[DATA_COLOR_INDEX]]
559:         end
560:       end
561:     end

Finds the best background to render based on the provided theme options.

Creates a @base_image to draw on.

[Source]

     # File lib/gruff/base.rb, line 895
895:     def render_background
896:       case @theme_options[:background_colors]
897:       when Array
898:         @base_image = render_gradiated_background(*@theme_options[:background_colors])
899:       when String
900:         @base_image = render_solid_background(@theme_options[:background_colors])
901:       else
902:         @base_image = render_image_background(*@theme_options[:background_image])
903:       end
904:     end

Use with a theme definition method to draw a gradiated background.

[Source]

     # File lib/gruff/base.rb, line 914
914:     def render_gradiated_background(top_color, bottom_color)
915:       Image.new(@columns, @rows,
916:                 GradientFill.new(0, 0, 100, 0, top_color, bottom_color))
917:     end

Use with a theme to use an image (800x600 original) background.

[Source]

     # File lib/gruff/base.rb, line 920
920:     def render_image_background(image_path)
921:       image = Image.read(image_path)
922:       if @scale != 1.0
923:         image[0].resize!(@scale) # TODO Resize with new scale (crop if necessary for wide graph)
924:       end
925:       image[0]
926:     end

Make a new image at the current size with a solid color.

[Source]

     # File lib/gruff/base.rb, line 907
907:     def render_solid_background(color)
908:       Image.new(@columns, @rows) {
909:         self.background_color = color
910:       }
911:     end

Use with a theme to make a transparent background

[Source]

     # File lib/gruff/base.rb, line 929
929:     def render_transparent_background
930:       Image.new(@columns, @rows) do
931:         self.background_color = 'transparent'
932:       end
933:     end

Resets everything to defaults (except data).

[Source]

     # File lib/gruff/base.rb, line 936
936:     def reset_themes
937:       @color_index = 0
938:       @labels_seen = {}
939:       @theme_options = {}
940: 
941:       @d = Draw.new
942:       # Scale down from 800x600 used to calculate drawing.
943:       @d = @d.scale(@scale, @scale)
944:     end

Return a comparable fontsize for the current graph.

[Source]

     # File lib/gruff/base.rb, line 951
951:     def scale_fontsize(value)
952:       new_fontsize = value * @scale
953:       # return new_fontsize < 10.0 ? 10.0 : new_fontsize
954:       return new_fontsize
955:     end

Calculates size of drawable area and draws the decorations.

  • line markers
  • legend
  • title

[Source]

     # File lib/gruff/base.rb, line 524
524:     def setup_drawing
525:       # Maybe should be done in one of the following functions for more granularity.
526:       unless @has_data
527:         draw_no_data()
528:         return
529:       end
530: 
531:       normalize()
532:       setup_graph_measurements()
533:       sort_norm_data() if @sort # Sort norm_data with avg largest values set first (for display)
534: 
535:       draw_legend()
536:       draw_line_markers()
537:       draw_axis_labels()
538:       draw_title
539:     end

Calculates size of drawable area, general font dimensions, etc.

[Source]

     # File lib/gruff/base.rb, line 571
571:     def setup_graph_measurements
572:       @marker_caps_height = @hide_line_markers ? 0 :
573:         calculate_caps_height(@marker_font_size)
574:       @title_caps_height = @hide_title ? 0 :
575:         calculate_caps_height(@title_font_size)
576:       @legend_caps_height = @hide_legend ? 0 :
577:         calculate_caps_height(@legend_font_size)
578: 
579:       if @hide_line_markers
580:         (@graph_left,
581:          @graph_right_margin,
582:          @graph_bottom_margin) = [@left_margin, @right_margin, @bottom_margin]
583:       else
584:         longest_left_label_width = 0
585:         if @has_left_labels
586:           longest_left_label_width =  calculate_width(@marker_font_size,
587:                                                       labels.values.inject('') { |value, memo| (value.to_s.length > memo.to_s.length) ? value : memo }) * 1.25
588:         else
589:           longest_left_label_width = calculate_width(@marker_font_size,
590:                                                      label(@maximum_value.to_f))
591:         end
592: 
593:         # Shift graph if left line numbers are hidden
594:         line_number_width = @hide_line_numbers && !@has_left_labels ?
595:         0.0 :
596:           (longest_left_label_width + LABEL_MARGIN * 2)
597: 
598:         @graph_left = @left_margin +
599:           line_number_width +
600:           (@y_axis_label.nil? ? 0.0 : @marker_caps_height + LABEL_MARGIN * 2)
601: 
602:         # Make space for half the width of the rightmost column label.
603:         # Might be greater than the number of columns if between-style bar markers are used.
604:         last_label = @labels.keys.sort.last.to_i
605:         extra_room_for_long_label = (last_label >= (@column_count-1) && @center_labels_over_point) ?
606:         calculate_width(@marker_font_size, @labels[last_label]) / 2.0 :
607:           0
608:         @graph_right_margin = @right_margin + extra_room_for_long_label
609: 
610:         @graph_bottom_margin = @bottom_margin +
611:           @marker_caps_height + LABEL_MARGIN
612:       end
613: 
614:       @graph_right = @raw_columns - @graph_right_margin
615:       @graph_width = @raw_columns - @graph_left - @graph_right_margin
616: 
617:       # When @hide title, leave a title_margin space for aesthetics.
618:       # Same with @hide_legend
619:       @graph_top = @top_margin +
620:         (@hide_title  ? title_margin  : @title_caps_height  + title_margin ) +
621:         (@hide_legend ? legend_margin : @legend_caps_height + legend_margin)
622: 
623:       x_axis_label_height = @x_axis_label.nil? ? 0.0 :
624:         @marker_caps_height + LABEL_MARGIN
625:       @graph_bottom = @raw_rows - @graph_bottom_margin - x_axis_label_height
626:       @graph_height = @graph_bottom - @graph_top
627:     end

Sort with largest overall summed value at front of array so it shows up correctly in the drawn graph.

[Source]

      # File lib/gruff/base.rb, line 1003
1003:     def sort_norm_data
1004:       @norm_data.sort! { |a,b| sums(b[DATA_VALUES_INDEX]) <=> sums(a[DATA_VALUES_INDEX]) }
1005:     end

Return the sum of values in an array.

Duplicated to not conflict with active_support in Rails.

[Source]

     # File lib/gruff/base.rb, line 749
749:     def sum(arr)
750:       arr.inject(0) { |i, m| m + i }
751:     end

Private Instance methods

Returns the height of the capital letter ‘X’ for the current font and size.

Not scaled since it deals with dimensions that the regular scaling will handle.

[Source]

      # File lib/gruff/base.rb, line 1086
1086:     def calculate_caps_height(font_size)
1087:       @d.pointsize = font_size
1088:       @d.get_type_metrics(@base_image, 'X').height
1089:     end

Returns the width of a string at this pointsize.

Not scaled since it deals with dimensions that the regular scaling will handle.

[Source]

      # File lib/gruff/base.rb, line 1095
1095:     def calculate_width(font_size, text)
1096:       @d.pointsize = font_size
1097:       @d.get_type_metrics(@base_image, text.to_s).width
1098:     end

Takes a block and draws it if DEBUG is true.

Example:

  debug { @d.rectangle x1, y1, x2, y2 }

[Source]

      # File lib/gruff/base.rb, line 1049
1049:     def debug
1050:       if DEBUG
1051:         @d = @d.fill 'transparent'
1052:         @d = @d.stroke 'turquoise'
1053:         @d = yield
1054:       end
1055:     end

Returns the next color in your color list.

[Source]

      # File lib/gruff/base.rb, line 1058
1058:     def increment_color
1059:       @color_index = (@color_index + 1) % @colors.length
1060:       return @colors[@color_index - 1]
1061:     end

Return a formatted string representing a number value that should be printed as a label.

[Source]

      # File lib/gruff/base.rb, line 1065
1065:     def label(value)
1066:       label = if (@spread.to_f % @marker_count.to_f == 0) || !@y_axis_increment.nil?
1067:         value.to_i.to_s
1068:       elsif @spread > 10.0
1069:         sprintf("%0i", value)
1070:       elsif @spread >= 3.0
1071:         sprintf("%0.2f", value)
1072:       else
1073:         value.to_s
1074:       end
1075:       
1076:       parts = label.split('.')
1077:       parts[0].gsub!(/(\d)(?=(\d\d\d)+(?!\d))/, "\\1#{THOUSAND_SEPARATOR}")
1078:       parts.join('.')
1079:     end

[Validate]