Class: RubyTUI::Widgets::Chart

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

Overview

Chart renders line charts using Canvas (Braille) for high-resolution plotting. Supports multiple datasets, labeled axes, and automatic scaling.

Examples:

ds = RubyTUI::Widgets::Dataset.new(name: "load", data: [[0, 1], [1, 3], [2, 2]])
chart = RubyTUI::Widgets::Chart.new(datasets: [ds], x_axis: ["t", 0, 2], y_axis: ["y", 0, 4])
frame.render_widget(chart, area)

See Also:

Instance Method Summary collapse

Constructor Details

#initialize(datasets: [], x_axis: nil, y_axis: nil, style: Style::DEFAULT, axis_style: nil, label_style: nil, block: nil) ⇒ Chart

Returns a new instance of Chart.

Parameters:

  • datasets (Array<Dataset>) (defaults to: []) —

    series to plot; datasets with fewer than 2 points are skipped (default: [])

  • x_axis (Array(String, Numeric, Numeric), nil) (defaults to: nil) —

    [label, min, max]; +min+/+max+ may be nil for bounds computed from the data. When set, one row is reserved for the axis and the label is drawn centered on it (default: nil, bounds computed from the data and no row reserved)

  • y_axis (Array(String, Numeric, Numeric), nil) (defaults to: nil) —

    [label, min, max]; +min+/+max+ may be nil for bounds computed from the data. When set, the min/max values are drawn left of a vertical axis line and the label's first character at mid-height (default: nil, no y axis; bounds computed from the data)

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

    currently unused by rendering (default: Style::DEFAULT)

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

    axis line style (default: bright black foreground)

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

    style of axis labels and min/max values (default: white foreground)

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

    optional wrapping block



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# File 'lib/rubytui/widgets/chart.rb', line 44

def initialize(
  datasets: [],
  x_axis: nil,        # [label, min, max] or nil for auto
  y_axis: nil,        # [label, min, max] or nil for auto
  style: Style::DEFAULT,
  axis_style: nil,
  label_style: nil,
  block: nil
)
  @datasets = datasets
  @x_axis = x_axis
  @y_axis = y_axis
  @style = style
  @axis_style = axis_style || Style.new.fg(Color::BRIGHT_BLACK)
  @label_style = label_style || Style.new.fg(Color::WHITE)
  @block = block
end

Instance Method Details

#render(area, buf) ⇒ void

This method returns an undefined value.

Render the axes and draw each dataset as connected line segments on a RubyTUI::Widgets::Canvas.

Nothing is drawn, not even block, when there are no datasets.

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/chart.rb', line 69

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

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

  return if render_area.empty?

  # Reserve space for axes
  y_label_width = compute_y_label_width
  x_label_height = @x_axis ? 1 : 0
  y_label_area_width = y_label_width > 0 ? y_label_width + 1 : 0

  chart_area = Rect.new(
    x: render_area.x + y_label_area_width,
    y: render_area.y,
    width: [render_area.width - y_label_area_width, 0].max,
    height: [render_area.height - x_label_height, 0].max
  )

  return if chart_area.empty?

  # Compute data bounds
  x_min, x_max = compute_x_bounds
  y_min, y_max = compute_y_bounds

  # Draw axes
  render_y_axis(render_area, chart_area, buf, y_min, y_max)
  render_x_axis(render_area, chart_area, buf, x_min, x_max)

  # Draw data using Canvas
  canvas = Canvas.new(
    x_bounds: [x_min, x_max],
    y_bounds: [y_min, y_max]
  )

  @datasets.each do |ds|
    points = ds.data
    next if points.length < 2

    # Draw lines between consecutive points
    points.each_cons(2) do |(x1, y1), (x2, y2)|
      canvas.line(x1, y1, x2, y2, style: ds.style)
    end
  end

  canvas.render(chart_area, buf)
end