Class: Rufio::Renderer

Inherits:
Object
  • Object
show all
Defined in:
lib/rufio/renderer.rb

Overview

Renderer class - Front buffer for double buffering

Manages the front buffer (what’s currently displayed on screen) and performs differential rendering by comparing with the back buffer (Screen).

Features:

  • Diff rendering: Only updates changed lines

  • Cursor positioning: Uses ANSI escape codes

  • Flush control: Ensures all output is displayed

Instance Method Summary collapse

Constructor Details

#initialize(width, height, output: STDOUT) ⇒ Renderer

Returns a new instance of Renderer.



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# File 'lib/rufio/renderer.rb', line 15

def initialize(width, height, output: STDOUT)
  @width = width
  @height = height
  @front = Array.new(height) { " " * width }
  @output = output
end

Instance Method Details

#clear ⇒ Object

Clear the front buffer and screen



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# File 'lib/rufio/renderer.rb', line 76

def clear
  @front = Array.new(@height) { " " * @width }

  # Clear screen and move cursor to home
  @output.print "\e[2J\e[H"
  @output.flush
end

#render(screen) ⇒ Boolean

Render the screen with differential updates

Parameters:

  • screen (Screen) —

    The back buffer to render

Returns:

  • (Boolean) —

    true if rendering was performed, false if skipped



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# File 'lib/rufio/renderer.rb', line 26

def render(screen)
  # CPU最適化: Dirty rowsが空の場合は完全にスキップ
  dirty = screen.dirty_rows
  if dirty.empty?
    return false
  end

  # Phase1: Only process dirty rows (rows that have changed)
  # 全dirty rowsの出力を1つのバッファに積んでから単一の write() で書き出す。
  # STDOUT sync=true 環境で print を行ごとに呼ぶと各行で即座にフラッシュされ
  # 中間状態が表示されてちらつきが発生するため、アトミックな更新を保証する。
  buf = String.new("")
  rendered_count = 0
  dirty.each do |y|
    line = screen.row(y)
    next if line == @front[y]  # Skip if content is actually the same

    # Move cursor to line y (1-indexed) and buffer the line
    buf << "\e[#{y + 1};1H#{line}"
    @front[y] = line
    rendered_count += 1
  end

  # Phase1: Clear dirty tracking after rendering
  screen.clear_dirty

  # 単一の write() でアトミックに出力し、その後 flush する
  if rendered_count > 0
    @output.write(buf)
    @output.flush
  end

  true
end

#resize(width, height) ⇒ Object

Resize the front buffer

Parameters:

  • width (Integer) —

    New width

  • height (Integer) —

    New height



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# File 'lib/rufio/renderer.rb', line 65

def resize(width, height)
  @width = width
  @height = height
  @front = Array.new(height) { " " * width }

  # Clear entire screen
  @output.print "\e[2J\e[H"
  @output.flush
end