projects.mako.cc - selectricity/blob - lib/gruff-0.2.8/lib/gruff/mini/legend.rb

   1 module Gruff
   2   module Mini
   3     module Legend
   4
   5       ##
   6       # The canvas needs to be bigger so we can put the legend beneath it.
   7
   8       def expand_canvas_for_vertical_legend
   9         @original_rows = @raw_rows
  10         @rows += @data.length * calculate_caps_height(scale_fontsize(@legend_font_size)) * 1.7
  11         render_background
  12       end
  13
  14       ##
  15       # Draw the legend beneath the existing graph.
  16
  17       def draw_vertical_legend
  18
  19         @legend_labels = @data.collect {|item| item[Gruff::Base::DATA_LABEL_INDEX] }
  20
  21         legend_square_width = 40.0 # small square with color of this item
  22         legend_square_margin = 10.0
  23         @legend_left_margin = 40.0
  24         legend_top_margin = 40.0
  25
  26         # May fix legend drawing problem at small sizes
  27         @d.font = @font if @font
  28         @d.pointsize = @legend_font_size
  29
  30         current_x_offset = @graph_left + @legend_left_margin
  31         current_y_offset = @original_rows + legend_top_margin
  32
  33         debug { @d.line 0.0, current_y_offset, @raw_columns, current_y_offset }
  34
  35         @legend_labels.each_with_index do |legend_label, index|
  36
  37           # Draw label
  38           @d.fill = @font_color
  39           @d.font = @font if @font
  40           @d.pointsize = scale_fontsize(@legend_font_size)
  41           @d.stroke = 'transparent'
  42           @d.font_weight = Magick::NormalWeight
  43           @d.gravity = Magick::WestGravity
  44           @d = @d.annotate_scaled( @base_image,
  45                             @raw_columns, 1.0,
  46                             current_x_offset + (legend_square_width * 1.7), current_y_offset,
  47                             truncate_legend_label(legend_label), @scale)
  48
  49           # Now draw box with color of this dataset
  50           @d = @d.stroke 'transparent'
  51           @d = @d.fill @data[index][Gruff::Base::DATA_COLOR_INDEX]
  52           @d = @d.rectangle(current_x_offset,
  53                             current_y_offset - legend_square_width / 2.0,
  54                             current_x_offset + legend_square_width,
  55                             current_y_offset + legend_square_width / 2.0)
  56
  57           current_y_offset += calculate_caps_height(@legend_font_size) * 1.7
  58         end
  59         @color_index = 0
  60       end
  61
  62       ##
  63       # Shorten long labels so they will fit on the canvas.
  64       #
  65       #   Department of Hu...
  66
  67       def truncate_legend_label(label)
  68         truncated_label = label.to_s
  69         while calculate_width(scale_fontsize(@legend_font_size), truncated_label) > (@columns - @legend_left_margin - Gruff::Base::RIGHT_MARGIN) && (truncated_label.length > 1)
  70           truncated_label = truncated_label[0..truncated_label.length-2]
  71         end
  72         truncated_label + (truncated_label.length < label.to_s.length ? "…" : '')
  73       end
  74
  75     end
  76   end
  77 end