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Architecture & Data Flow

This document explains how Rich Ruby processes text and components to generate terminal output.

1. High-Level Concept

Rich Ruby follows a pipeline: Input (Markup/Object) -> Text/Segments -> Console Options -> ANSI String -> Terminal

2. Core Entities

Rich::Console

The "brain" of the library. It holds state about the terminal's width, height, and color capabilities. It acts as the orchestrator for all rendering.

Rich::Text

A representation of text that includes "Spans" (range of characters + a Style). This is an intermediate format before splitting into segments.

Rich::Segment

The lowest-level rendering unit. A segment is a simple string paired with a Rich::Style.

  • When you render any component (Table, Panel, etc.), it ultimately breaks down into a list of Segments.
  • Segments are responsible for generating the final ANSI escape codes via Segment.render.

Rich::Style

Encapsulates foreground color, background color, and attributes (bold, etc.). Styles are immutable. Combining styles (style1 + style2) creates a new style object.

3. The Rendering Pipeline

  1. Measurement: Components (like Table) calculate the required width of each cell using Rich::Cells.cell_len.
  2. Layout: Wrapping and alignment logic is applied to fit the max_width.
  3. Segmentation: The component converts its visual structure into Rich::Segment objects.
  4. ANSI Generation: The Console takes the segments and joins them into a single string containing escape sequences.
  5. Output: The string is written to $stdout (or the configured output stream).

4. Windows Integration Logic

In lib/rich/win32_console.rb, we use Fiddle to interface with kernel32.dll:

  • VT Processing: We call GetConsoleMode and SetConsoleMode to enable ANSI support.
  • Size Detection: We call GetConsoleScreenBufferInfo to get accurate dimensions without relying on environment variables.

5. Extensibility

Developers can create new components by implementing a render (or to_segments) method that returns a collection of Rich::Segment objects. This ensures that any new component automatically inherits font-width calculation and color-downgrade support.