Class: Charming::Internal::Renderer::Differential

Inherits:
Object
  • Object
show all
Defined in:
lib/charming/internal/renderer/differential.rb

Overview

Differential renders frame updates by emitting only the lines that changed since the previous frame. On the first frame it falls back to a full repaint; when no lines changed it returns without writing anything.

Instance Method Summary collapse

Constructor Details

#initialize(output, full_renderer: FullRepaint.new(output)) ⇒ Differential

output is the terminal backend (must support ‘write_lines` for the differential path or `write_frame` for the fallback). full_renderer is the FullRepaint used for the initial frame and as a fallback when output doesn’t support partial writes.



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# File 'lib/charming/internal/renderer/differential.rb', line 13

def initialize(output, full_renderer: FullRepaint.new(output))
  @output = output
  @full_renderer = full_renderer
  @previous_frame = nil
end

Instance Method Details

#render(frame) ⇒ Object

Renders frame. The first call performs a full repaint and stores the frame. Subsequent calls compute the per-line diff and emit only changed rows. Returns nil when the frame is identical to the previous one.



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# File 'lib/charming/internal/renderer/differential.rb', line 22

def render(frame)
  frame = frame.to_s
  return render_initial(frame) unless @previous_frame
  return if frame == @previous_frame

  render_changes(frame)
end