Class: RubyTUI::Widgets::Sparkline

Inherits:
Object
  • Object
show all
Includes:
RubyTUI::Widget
Defined in:
lib/rubytui/widgets/sparkline.rb

Overview

Sparkline renders a mini bar chart from an array of numeric data. Each data point maps to a single column using Unicode block characters.

Examples:

spark = RubyTUI::Widgets::Sparkline.new(data: [1, 4, 2, 8, 5], max: 10)
frame.render_widget(spark, area)

Constant Summary collapse

BARS =

Bar characters from empty to full (8 levels)

[" ", "\u2581", "\u2582", "\u2583", "\u2584", "\u2585", "\u2586", "\u2587", "\u2588"].freeze

Instance Method Summary collapse

Constructor Details

#initialize(data: [], style: Style::DEFAULT, bar_style: nil, max: nil, block: nil) ⇒ Sparkline

Returns a new instance of Sparkline.

Parameters:

  • data (Array<Numeric>) (defaults to: []) —

    values; the most recent values that fit the width are drawn, right-aligned (default: [])

  • style (Style) (defaults to: Style::DEFAULT) —

    style of the empty cells above the bars (default: Style::DEFAULT)

  • bar_style (Style, nil) (defaults to: nil) —

    bar style (default: green foreground)

  • max (Numeric, nil) (defaults to: nil) —

    value drawn at full height; larger values are clamped to full height (default: nil, the largest visible value, or 1 if that is 0)

  • block (Widgets::Block, nil) (defaults to: nil) —

    optional wrapping block



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# File 'lib/rubytui/widgets/sparkline.rb', line 24

def initialize(
  data: [],
  style: Style::DEFAULT,
  bar_style: nil,
  max: nil,
  block: nil
)
  @data = data
  @style = style
  @bar_style = bar_style || Style.new.fg(Color::GREEN)
  @max = max
  @block = block
end

Instance Method Details

#render(area, buf) ⇒ void

This method returns an undefined value.

Draw one column per value, bottom-up, with eighth-cell height precision.

Parameters:

  • area (Rect) —

    the rectangular area to render into

  • buf (Buffer) —

    the buffer to write cells into



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# File 'lib/rubytui/widgets/sparkline.rb', line 43

def render(area, buf)
  return if area.empty?

  render_area = area
  if @block
    @block.render(area, buf)
    render_area = @block.inner(area)
  end

  return if render_area.empty? || @data.empty?

  width = render_area.width
  height = render_area.height

  # Use the most recent data points that fit
  visible_data = @data.last(width)
  max_val = @max || visible_data.max || 1
  max_val = 1 if max_val == 0

  visible_data.each_with_index do |val, i|
    x = render_area.x + (width - visible_data.length) + i
    next if x < render_area.x

    # Scale value to available height * 8 (for sub-character precision)
    scaled = ((val.to_f / max_val) * height * 8).round.clamp(0, height * 8)

    # Render from bottom to top
    (0...height).each do |row|
      y = render_area.bottom - 1 - row
      row_value = scaled - (row * 8)

      if row_value >= 8
        buf[x, y]&.set(BARS[8], @bar_style)
      elsif row_value > 0
        buf[x, y]&.set(BARS[row_value], @bar_style)
      else
        buf[x, y]&.set(" ", @style)
      end
    end
  end
end