Method: PDF::Charts::StdDev#render_on

Defined in:

lib/extensions/pdf-writer/pdf/charts/stddev.rb

#render_on(pdf) ⇒ Object

Draw the standard deviation chart on the supplied PDF document.

Raises:

• (TypeError)

# File 'lib/extensions/pdf-writer/pdf/charts/stddev.rb', line 219

def render_on(pdf)
  raise TypeError, PDF::Writer::Lang[:charts_stddev_data_empty] if @data.empty?
  data = @data.dup
  leftover_data = nil

  loop do
    # Set up the scale information.
    scale = []

    (@scale.first + @scale.step).step(@scale.last, @scale.step) do |ii|
      scale << "%01.#{@scale.label.decimal_precision}f" % ii
    end

    scales = PDF::Writer::OHash.new
    scale.each_with_index do |gg, ii|
      scales[ii] = OpenStruct.new
      scales[ii].value = gg
    end

    # Add information about the scales' locations to the scales
    # hash. Note that the count is one smaller than it should be, so we're
    # increasing it. The first scale is the bottom of the chart.
    scale_count = scale.size + 1

    label_height_adjuster = 0
    label_height_adjuster = @label.height if @show_labels

    chart_area_height = @height - label_height_adjuster
    scale_height   = chart_area_height / scale_count.to_f

    scales.each_key do |index|
      this_height = scale_height * (index + 1) + @label.height
      scales[index].line_height = this_height
      if @scale.show_labels
        scales[index].label_height = this_height -
        (@scale.label.text_size / 3.0)
      end
    end

    # How many sections do we need in this chart, and how wide will it
    # need to be?
    chunk_width = @datapoint_width
    num_chunks  = data.size
    widest_scale_label = 0

    if @scale.show_labels
      scales.each_value do |scale|
        this_width = pdf.text_width(scale.value, @scale.label.text_size)
        widest_scale_label = this_width if this_width > widest_scale_label
      end
    end

    chart_width = chunk_width * num_chunks
    total_width = chart_width + widest_scale_label + @scale.label.pad

      # What happens if the projected width of the chart is too big?
      # Figure out how to break the chart in pieces.
    if total_width > @maximum_width
      max_column_count = 0
      base_width = widest_scale_label + @scale.label.pad
      (1..(num_chunks + 1)).each do |ii|
        if (base_width + (ii * chunk_width)) > @maximum_width
          break
        else
          max_column_count += 1
        end
      end

      leftover_data = data.slice!(max_column_count, -1)

      num_chunks  = data.size
      chart_width = chunk_width * num_chunks
      total_width = chart_width + widest_scale_label + @scale.label.pad
    end

    chart_y = pdf.y - @height + @leading_gap
    chart_y += (@outer_borders.style.width * 2.0) if @outer_borders

    if chart_y < pdf.bottom_margin
      pdf.start_new_page
      chart_y = pdf.y - @height
      chart_y += (@outer_borders.style.width * 2.0) if @outer_borders
    end

    chart_x = pdf.absolute_x_middle - (total_width / 2.0) + widest_scale_label

      # Add labels, if needed.
    if @show_labels
      pdf.save_state
      pdf.fill_color! @label.background_color
      # Draw a rectangle for each label
      num_chunks.times do |ii|
        this_x = chart_x + ii * chunk_width
        pdf.rectangle(this_x, chart_y, chunk_width, @label.height).fill
      end

        # Add a border above the label rectangle.
      if @outer_borders
        pdf.stroke_style! @outer_borders.style
        pdf.line(chart_x, chart_y + @label.height, chart_x + chart_width, chart_y + @label.height).stroke
      end
      pdf.fill_color! @label.text_color

      data.each_with_index do |datum, ii|
        label = datum.label.to_s
        label_width = pdf.text_width(label, @label.text_size)
        this_x = chart_x + (ii * chunk_width) + (chunk_width / 2.0) - (label_width / 2.0)
        this_y = chart_y + (@label.height / 2.0) - (@label.text_size / 3.0)
        pdf.add_text(this_x, this_y, label, @label.text_size)
      end
      pdf.restore_state
    end

    if @inner_borders
      pdf.save_state
      pdf.stroke_color! @inner_borders.color
      pdf.stroke_style! @inner_borders.style
      (num_chunks - 1).times do |ii|
        this_x = chart_x + (ii * chunk_width) + chunk_width
        pdf.line(this_x, chart_y, this_x, chart_y + @height).stroke
      end
      pdf.restore_state
    end

    pdf.save_state
    if @outer_borders
      pdf.stroke_color! @outer_borders.color
      pdf.stroke_style! @outer_borders.style
      pdf.rectangle(chart_x, chart_y, chart_width, @height).stroke
    end

    if @scale.style
      pdf.save_state
      pdf.stroke_style! @scale.style
      scales.each_value do |scale|
        this_y = chart_y + scale.line_height
        pdf.line(chart_x, this_y, chart_x + chart_width, this_y).stroke
      end
      pdf.restore_state
    end

    if @scale.show_labels
      pdf.save_state
      scales.each_value do |scale|
        this_y = chart_y + scale.label_height
        label_width = pdf.text_width(scale.value, @scale.label.text_size)
        this_x = chart_x - label_width - @scale.label.pad
        pdf.fill_color! @scale.label.text_color
        pdf.add_text(this_x, this_y, scale.value, @scale.label.text_size)
      end
      pdf.restore_state
    end

    data.each_with_index do |datum, ii|
      avg_height    = datum.average * scale_height
      stddev_height = datum.stddev * scale_height
      this_y        = chart_y + label_height_adjuster + avg_height
      this_x        = chart_x + (ii * chunk_width) + (chunk_width / 2.0)
      line_top_y    = this_y + (stddev_height / 2.0)
      line_bot_y    = this_y - (stddev_height / 2.0)

        # Plot the dot
      if @dot
        pdf.stroke_color! @dot.color
        pdf.stroke_style! @dot.style
        pdf.circle_at(this_x, this_y, (@dot.style.width / 2.0)).fill
      end

        # Plot the bar
      if @bar
        pdf.stroke_color! @bar.color
        pdf.stroke_style! @bar.style
        pdf.line(this_x, line_top_y, this_x, line_bot_y).stroke
      end

        # Plot the crossbars
      if @upper_crossbar
        if @dot
          cb_width = @dot.style.width
        else
          cb_width = @upper_crossbar.style.width
        end
        pdf.stroke_color! @upper_crossbar.color
        pdf.stroke_style! @upper_crossbar.style
        pdf.line(this_x - cb_width, line_top_y, this_x + cb_width, line_top_y).stroke
      end
      if @lower_crossbar
        if @dot
          cb_width = @dot.style.width
        else
          cb_width = @lower_crossbar.style.width
        end
        pdf.stroke_color! @lower_crossbar.color
        pdf.stroke_style! @lower_crossbar.style

        pdf.line(this_x - cb_width, line_bot_y, this_x + cb_width, line_bot_y).stroke
      end
    end

    pdf.restore_state

    pdf.y = chart_y

    break if leftover_data.nil?

    data = leftover_data
    leftover_data = nil
  end

  pdf.y
end