A terminal-based color picker application.

Terminal users often need to select colors for themes or UI components. Manually typing hex codes and guessing how they will look is slow and error-prone.

This application solves the problem by providing an interactive interface. It parses hex strings, generates palettes, and displays them visually in the terminal.

Use it to experiment with color combinations and quickly find the right hex codes.

Examples

AppColorPicker.new.run

Source Code

# frozen_string_literal: true

# SPDX-FileCopyrightText: 2025 Kerrick Long <me@kerricklong.com>
# SPDX-License-Identifier: AGPL-3.0-or-later

$LOAD_PATH.unshift File.expand_path("../../lib", __dir__)
$LOAD_PATH.unshift File.expand_path(__dir__)

require "ratatui_ruby"
require_relative "input"
require_relative "palette"
require_relative "clipboard"
require_relative "copy_dialog"
require_relative "scene"

# A terminal-based color picker application.
#
# Terminal users often need to select colors for themes or UI components.
# Manually typing hex codes and guessing how they will look is slow and error-prone.
#
# This application solves the problem by providing an interactive interface. It parses hex strings,
# generates palettes, and displays them visually in the terminal.
#
# Use it to experiment with color combinations and quickly find the right hex codes.
#
# === Examples
#
#   AppColorPicker.new.run
#
class AppColorPicker
  # Creates a new <tt>AppColorPicker</tt> instance with a default palette and clipboard.
  def initialize
    @input = Input.new
    @palette = Palette.new(@input.parse)
    @clipboard = Clipboard.new
    @dialog = CopyDialog.new(@clipboard)
    @scene = nil
  end

  # Starts the terminal session and enters the main event loop.
  #
  # This method initializes the terminal, renders the initial scene, and polls for
  # input until the user quits.
  #
  # === Example
  #
  #   app = AppColorPicker.new
  #   app.run
  #
  def run
    RatatuiRuby.run do |tui|
      @scene = Scene.new(tui)
      loop do
        render(tui)
        result = handle_input(tui)
        break if result == :quit
      end
    end
  end

  private def render(tui)
    @clipboard.tick
    tui.draw do |frame|
      @scene.render(frame, input: @input, palette: @palette, clipboard: @clipboard, dialog: @dialog)
    end
  end

  private def handle_input(tui)
    event = tui.poll_event
    @input.clear_error unless @dialog.active?

    if @dialog.active?
      handle_dialog_input(event)
    else
      handle_main_input(event)
    end
  end

  private def handle_dialog_input(event)
    result = @dialog.handle_input(event)
    case event
    in { type: :key, code: "q" } | { type: :key, code: "esc" } | { type: :key, code: "c", modifiers: ["ctrl"] }
      :quit
    else
      result
    end
  end

  private def handle_main_input(event)
    case event
    in { type: :key, code: "q" } | { type: :key, code: "esc" } | { type: :key, code: "c", modifiers: ["ctrl"] }
      :quit
    in { type: :key, code: "enter" }
      @palette = Palette.new(@input.parse)
    in { type: :key, code: "backspace" }
      @input.delete_char
    in { type: :paste, content: }
      @input.set(content)
      @palette = Palette.new(@input.parse)
    in { type: :key, code: code }
      @input.append_char(code)
    in { type: :mouse, kind: "down", button: "left", x:, y: }
      if @scene && @scene.export_rect&.contains?(x, y) && @palette.main
        @dialog.open(@palette.main.hex)
      end
    else
      nil
    end
  end
end

AppColorPicker.new.run if __FILE__ == $PROGRAM_NAME