Class: Tuile::Screen

Inherits:
Object
  • Object
show all
Defined in:
lib/tuile/screen.rb,
sig/tuile.rbs

Overview

The process-singleton runtime: one Screen per app, reached through Screen.instance. It owns everything the UI needs to exist — the #event_queue, the UI lock, the invalidation set, the terminal IO, the back #buffer, the #theme/#theme_def, the #focused component, the global-shortcut registry, and the single ScreenPane under which all UI lives. Construct one with Screen.new (or Screen.fake in tests), tear it down with Screen.close.

The component tree

Everything on screen hangs off #pane (a ScreenPane): the tiled #content (set via #content=, filling the whole terminal and laying out its own children), the modal/overlay #popups stack (opened via Component::Overlay#open, drawn on top of the content). Popups are not sized from their content — each carries its own top-down Component::Popup#declared_size — and they deliberately overdraw the content without clipping.

Tuile draws no chrome of its own: there is no status bar and no reserved row, so #content gets the whole terminal. An app that wants a status line builds one into its own layout and drives it from #on_focus_changed= (D_status_bar).

Repaint model

Components never draw to the terminal directly. They call Component#invalidate to mark themselves dirty, and when they do paint they write styled cells into #buffer. Once the event loop drains its queue, #repaint walks the invalidated set in z-order, has each component paint into the buffer, then flushes the buffer's minimal diff (only cells that changed) to the terminal in one synchronized-output batch — which is what keeps repaint flicker-free and coalesces many invalidations into a single frame per tick. See the book (ch. 2) for the why.

Thread-safety

UI-thread-confined, where "the UI thread" changes hands once: it is the loop's thread while #run_event_loop is in progress, and the thread that created the screen whenever no loop is running (#state :idle). So an app builds its tree on its own thread, hands ownership to the loop, and gets it back for teardown — the loop needn't run on the creating thread. All UI mutations — #content=, #focused=, #theme=, Component#invalidate, rect=, … — obey it via #check_locked.

A worker marshals back with screen.event_queue.submit { … }, which runs the block only while a loop is draining the queue — outside :running it silently never fires. Terminal resize, key/mouse input and OS color-scheme flips arrive as events on that same queue.

The singleton slot survives subclassing (FakeScreen < Screen), so FakeScreen — which captures output in memory — is what Screen.instance returns under test.

Direct Known Subclasses

FakeScreen

Constant Summary collapse

EDITING_KEYS =

Keys #register_global_shortcut refuses because every editable widget needs them: the registry sits above the component tree, so binding one app-wide would silently break text entry everywhere — a Component::TextArea's newline, a caret move, a deletion. ENTER is the trap worth naming: it is unprintable, so nothing else stops it, and "bind Enter to submit" is the obvious wrong way to build a default button. The right way is a handle_key on the form itself, where a focused field still gets first refusal — see Tuile::ScreenPane#handle_key.

Deliberately not reserved: HOME/END/PAGE_UP/PAGE_DOWN. They move within a widget rather than mutate its value, and binding them app-wide (scroll the log pane) is a real use case.

Returns:

  • (Array<String>) 
[
  Keys::ENTER, Keys::DELETE, *Keys::BACKSPACES,
  Keys::UP_ARROW, Keys::DOWN_ARROW, Keys::LEFT_ARROW, Keys::RIGHT_ARROW,
  Keys::CTRL_LEFT_ARROW, Keys::CTRL_RIGHT_ARROW
].freeze
@@instance =

Class variable (not class instance var) so the singleton survives subclassing — FakeScreen < Screen and Screen.instance see the same slot.

nil

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Screen

rubocop:disable Style/ClassVars



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# File 'lib/tuile/screen.rb', line 62

def initialize
  @@instance = self # rubocop:disable Style/ClassVars
  @event_queue = EventQueue.new
  @size = EventQueue::TTYSizeEvent.create.size
  @invalidated = Set.new
  # Components being repainted right now. A component may invalidate its
  # children during its repaint phase; this prevents double-draw.
  @repainting = Set.new
  # The thread that owns the UI whenever no event loop is running — i.e.
  # during :idle, at both ends of the screen's life. See {#check_locked}.
  @ui_thread = Thread.current
  @closed = false
  background = detect_background
  @color_scheme = background.scheme
  @background_color = background.color
  @color_depth = detect_color_depth
  @theme_def = ThemeDef.default
  @theme = @theme_def.for(@color_scheme)
  # Structural root of the component tree: holds tiled content and the
  # popup stack.
  @pane = ScreenPane.new
  @on_error = ->(e) { raise e }
  # App-level keyboard shortcuts dispatched by {#handle_key} before keys
  # reach the pane. See {#register_global_shortcut}.
  @global_shortcuts = {}
  # The back buffer components paint into. {#repaint} flushes its diff to
  # the terminal, so only changed cells are emitted (flicker-free on any
  # terminal). Sized to the current viewport; {#layout} resizes it.
  @buffer = Buffer.new(@size, color_depth: @color_depth)
end

Instance Attribute Details

#background_color ⇒ Color? (readonly)

The terminal's own background, as it reported it — for deriving a color from the background rather than picking one against it. A pane tinted a few percent off it sits right on any terminal, where a fixed near-neutral only sits right near the one it was tuned on:

bg = screen.background_color
sidebar.bg_color =
bg ? Color.rgb(*bg.value.map { (_1 + 10).clamp(0, 255) }) : FALLBACK_TINT

Nil is the normal case, not an edge — a terminal answering only COLORFGBG, or neither probe, reports no RGB at all. Keep a fallback.

Kept current across OS appearance flips, a frame behind: the flip report carries light/dark only, so the screen re-probes and this updates when the reply lands. A changed color then fires Component#on_theme_changed across the tree exactly as a theme swap does — a background-derived tint is a theme-derived color.

Returns:



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# File 'lib/tuile/screen.rb', line 218

def background_color
  @background_color
end

#buffer ⇒ Buffer (readonly)

@return — the back buffer components paint into (Buffer#set_text / Buffer#fill / Buffer#set_char).

Returns:



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# File 'lib/tuile/screen.rb', line 137

def buffer
  @buffer
end

#color_depth ⇒ Symbol (readonly)

How many colors this terminal can show (ColorDepth::DEPTHS), detected at construction. Buffer#flush degrades every color it emits to this, so an app may compute an RGB tint — say from #background_color — and paint with it, whatever the terminal turns out to understand.

Deliberately read-only: detection runs once and the answer can't change mid-session. Override a terminal that reports itself wrong through ColorDepth::OVERRIDE_ENV instead.

Returns:

  • (Symbol) 


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# File 'lib/tuile/screen.rb', line 133

def color_depth
  @color_depth
end

#color_scheme ⇒ Symbol (readonly)

@return — :light or :dark

Returns:

  • (Symbol) 


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# File 'lib/tuile/screen.rb', line 122

def color_scheme
  @color_scheme
end

#event_queue ⇒ EventQueue (readonly)

@return — the event queue.

Returns:



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# File 'lib/tuile/screen.rb', line 260

def event_queue
  @event_queue
end

#focused ⇒ Component?

@return — currently focused component.

Returns:



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# File 'lib/tuile/screen.rb', line 317

def focused
  @focused
end

#on_error ⇒ Proc

Handler invoked when a StandardError escapes an event handler inside the event loop (e.g. a Component::TextField's on_change raises).

The default re-raises, so the exception propagates out of #run_event_loop and crashes the script with a stacktrace — unhandled exceptions are bugs and should be surfaced loudly.

Replace it when the host has somewhere visible to put errors, e.g. a Component::LogWindow wired to Tuile.logger:

screen.on_error = lambda do |e|
Tuile.logger.error("#{e.class}: #{e.message}\n#{e.backtrace&.join("\n")}")
end

The handler runs on the event-loop thread with the UI lock held. Returning normally keeps the loop alive; raising from within the handler tears the loop down and propagates out of #run_event_loop.

@return — one-arg callable receiving the StandardError instance.

Returns:

  • (Proc) 


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# File 'lib/tuile/screen.rb', line 157

def on_error
  @on_error
end

#on_focus_changed ⇒ Proc?

Called after the focused component changes — including to and from nil, and including the focus repair that runs when a popup closes. Takes no arguments; read #focused (and walk its parent chain) for the new state.

This is the hook an app drives its own status line from. Tuile owns no status bar and reserves no row: build a Component::Label into your own layout and fill it here (D_status_bar).

screen.on_focus_changed = -> { bar.text = hint_for(screen.focused) }

Edge-triggered, like Component#on_attached: re-assigning the component that already has focus fires nothing, so a callback can be as expensive as rebuilding a hint string without a did it really change? guard of its own. That matters more than it looks — ScreenPane#content= clears focus on every content swap, which on a level-triggered hook would fire a nil→nil notification during assembly.

It runs after the active-flag cascade and on_focus, so the tree is settled. Two things a callback must tolerate: #focused being nil, and firing during #close — teardown clears focus, exactly as it fires Component#on_detached. A raising callback propagates out of #focused= and leaves focus assigned; keep it trivial, as with the attach hooks.

Returns:

  • (Proc, nil) 


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# File 'lib/tuile/screen.rb', line 373

def on_focus_changed
  @on_focus_changed
end

#pane ⇒ ScreenPane (readonly)

@return — the structural root of the component tree.

Returns:



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# File 'lib/tuile/screen.rb', line 119

def pane
  @pane
end

#size ⇒ Size (readonly)

@return — current screen size.

Returns:



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# File 'lib/tuile/screen.rb', line 180

def size
  @size
end

#theme ⇒ Theme

The color Theme built-in components read at paint time: the member of #theme_def matching the terminal background detected at construction (see TerminalBackground.detect; inconclusive means dark). While the event loop runs, terminals supporting mode 2031 push OS appearance changes (EventQueue::ColorSchemeEvent) and the screen re-picks from #theme_def.

Returns:



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# File 'lib/tuile/screen.rb', line 189

def theme
  @theme
end

#theme_def ⇒ ThemeDef

The app's ThemeDef — the dark/light Theme pair the screen picks #theme from, at startup and on every OS appearance flip. Starts as ThemeDef.default (ThemeDef::DEFAULT unless reassigned — tests do, see ThemeDef.default=). Assigning a custom definition is the durable way to theme an app: unlike a bare #theme=, it survives the user toggling the OS appearance.

Returns:



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# File 'lib/tuile/screen.rb', line 198

def theme_def
  @theme_def
end

Class Method Details

.close ⇒ void

This method returns an undefined value.



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# File 'lib/tuile/screen.rb', line 581

def self.close
  @@instance&.close
end

.fake ⇒ FakeScreen

Testing only — creates new screen, locks the UI, and prevents any redraws, so that test TTY is not painted over. FakeScreen#initialize self-installs as the singleton, so subsequent instance calls return the same object.

Returns:



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# File 'lib/tuile/screen.rb', line 551

def self.fake = FakeScreen.new

.instance ⇒ Screen

@return — the singleton instance.

Returns:



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# File 'lib/tuile/screen.rb', line 160

def self.instance
  raise Tuile::Error, "Screen not initialized; call Screen.new first" if @@instance.nil?

  @@instance
end

Instance Method Details

#add_popup(window) ⇒ void

This method returns an undefined value.

Internal — use Component::Overlay#open instead. Adds the overlay to #pane; a Component::Popup is additionally centered and focused.

@param window — any overlay, modal or not.

Parameters:



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# File 'lib/tuile/screen.rb', line 380

def add_popup(window)
  check_locked
  @pane.add_popup(window)
  # No need to fully repaint the scene: a popup simply paints over the
  # current screen contents.
end

#beep ⇒ void

This method returns an undefined value.

Rings the terminal bell (Ansi::BEL) — the signal for a keystroke that went nowhere, e.g. a letter matching no menu mnemonic while a menu is open.

return true if activate_mnemonic(key)

screen.beep   # no match: the key is swallowed, say so
true

Writes immediately rather than riding the next frame: a beep is not part of a frame, and the keystrokes worth beeping at are precisely the ones that invalidate nothing, so #repaint may never emit at all. Whether the user hears anything is the terminal's setting to make, so there is no Tuile-level enable/disable knob.



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# File 'lib/tuile/screen.rb', line 617

def beep
  check_locked
  print(Ansi::BEL)
end

#check_locked ⇒ void

This method returns an undefined value.

Raises unless the calling thread currently owns the UI (see the class-level threading contract).

screen.check_locked   # from a worker: raises; wrap the work in
                    # screen.event_queue.submit { ... } instead


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# File 'lib/tuile/screen.rb', line 282

def check_locked
  raise Tuile::Error, "Screen is closed: no UI mutation is possible after Screen#close" if @closed
  return if @event_queue.running? ? @event_queue.on_loop_thread? : Thread.current.equal?(@ui_thread)

  # `submit` is the wrong remedy with no loop running — nothing would drain
  # the queue, so the block silently never fires.
  message = if @event_queue.running?
              "UI lock not held: UI mutations must run on the event-loop thread; " \
              "marshal via screen.event_queue.submit { ... }"
            else
              "UI not owned by #{Thread.current}: no event loop is running, so UI mutations must " \
              "come from #{@ui_thread}, the thread that created this screen " \
              "(or start the event loop first)"
            end
  raise Tuile::Error, message
end

#clear ⇒ void

This method returns an undefined value.

Clears the TTY screen.



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# File 'lib/tuile/screen.rb', line 301

def clear
  print TTY::Cursor.move_to(0, 0), TTY::Cursor.clear_screen
end

#close ⇒ void

This method returns an undefined value.

Tears the screen down and vacates the singleton slot, moving #state to the terminal :closed. Unmounts the tree first, so every component gets its Component#on_detached. Idempotent.



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# File 'lib/tuile/screen.rb', line 561

def close
  return if @closed

  raise Tuile::Error, "Screen is running: stop the event loop before closing" if state == :running

  check_locked
  begin
    @pane.detach_all
  ensure
    # A raising on_detached propagates — it's a bug to fix, not something the
    # framework guards — but teardown still has to finish, or one such bug
    # leaves a half-closed screen behind and every later example fails with it.
    clear
    @pane = nil
    @closed = true
    @@instance = nil # rubocop:disable Style/ClassVars
  end
end

#content ⇒ Component?

@return — tiled content (forwarded to Tuile::ScreenPane).

Returns:



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# File 'lib/tuile/screen.rb', line 167

def content = @pane.content

#content=(content) ⇒ void

This method returns an undefined value.

@param content

Parameters:



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# File 'lib/tuile/screen.rb', line 171

def content=(content)
  # Not left to ScreenPane#content='s own checks: after #close there's no
  # pane to forward to, and NoMethodError-for-nil is a poor error.
  check_locked
  @pane.content = content
  layout
end

#cursor_position ⇒ Point?

Returns the absolute screen coordinates where the hardware cursor should sit, or nil if it should be hidden. Only the #focused component owns the cursor: there can be multiple active components (the focus path), but only one focused.

Returns:



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# File 'lib/tuile/screen.rb', line 705

def cursor_position = @focused&.cursor_position

#cursor_sequence ⇒ String

The escape sequence positioning the hardware cursor for the current focus state: hidden when nothing owns it, else moved to the focused component's Component#cursor_position and shown. Appended to each frame's flush.

Returns:

  • (String) 


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# File 'lib/tuile/screen.rb', line 790

def cursor_sequence
  pos = cursor_position
  pos.nil? ? TTY::Cursor.hide : "#{TTY::Cursor.move_to(pos.x, pos.y)}#{TTY::Cursor.show}"
end

#cycle_focus(forward:) ⇒ Boolean

Walks the current modal scope in pre-order, collects tab stops, and advances focus by one (wrapping). When the focused component isn't in the tab order (e.g. focus is parked on a popup/window chrome with no interactable widgets), Tab goes to the first stop and Shift+Tab to the last.

@param forward

@return — true if focus moved.

Parameters:

  • forward: (Boolean)

Returns:

  • (Boolean) 


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# File 'lib/tuile/screen.rb', line 765

def cycle_focus(forward:)
  check_locked
  scope = @pane.modal_popup || @pane.content
  return false if scope.nil?

  stops = []
  scope.on_tree { |c| stops << c if c.tab_stop? }
  return false if stops.empty?

  idx = @focused.nil? ? nil : stops.index(@focused)
  target = if idx.nil?
             forward ? stops.first : stops.last
           else
             stops[(idx + (forward ? 1 : -1)) % stops.size]
           end
  return false if target.equal?(@focused)

  self.focused = target
  true
end

#detect_background ⇒ TerminalBackground::Result

The startup background probe, seeding #theme and #background_color. Inconclusive detection means :dark with no color. Runs in the constructor — the OSC 11 reply arrives on stdin, which is only safe to read before EventQueue#start_key_thread owns it. FakeScreen overrides this to pin the result, keeping specs deterministic and off the test runner's TTY.

Returns:



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# File 'lib/tuile/screen.rb', line 716

def detect_background
  TerminalBackground.detect || TerminalBackground::Result.new(scheme: :dark, color: nil)
end

#detect_color_depth ⇒ Symbol

The startup color-depth probe, seeding #color_depth. Reads the environment only, so unlike #detect_background it has no timing constraint. FakeScreen overrides it to pin the result, keeping specs off whatever COLORTERM the test runner happens to carry.

Returns:

  • (Symbol) 


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# File 'lib/tuile/screen.rb', line 725

def detect_color_depth = ColorDepth.detect

#emit(str) ⇒ void

This method returns an undefined value.

Writes an assembled frame (escape string) to the terminal. The single sink for repaint output; FakeScreen overrides it to capture instead.

@param str

Parameters:

  • str (String) 


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# File 'lib/tuile/screen.rb', line 799

def emit(str)
  $stdout.write(str)
  $stdout.flush
end

#event_loop ⇒ void

This method returns an undefined value.



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# File 'lib/tuile/screen.rb', line 869

def event_loop
  @event_queue.run_loop do |event|
    case event
    when EventQueue::KeyEvent
      key = event.key
      handled = handle_key(key)
      @event_queue.stop if !handled && ["q", Keys::ESC].include?(key)
    when EventQueue::PasteEvent
      handle_paste(event.text)
    when MouseEvent
      handle_mouse(event)
    when EventQueue::TTYSizeEvent
      @size = event.size
      layout
    when EventQueue::ColorSchemeEvent
      on_color_scheme(event.scheme)
    when EventQueue::BackgroundColorEvent
      on_background_color(event.color)
    when EventQueue::EmptyQueueEvent
      repaint
    when Proc
      event.call
    end
  rescue StandardError => e
    @on_error.call(e)
  end
end

#focus_next ⇒ Boolean

Advances focus to the next Component#tab_stop? in tree order, wrapping around. Scope is the topmost popup if one is open, otherwise #content — this keeps Tab confined inside a modal popup. No-op (returns false) if the modal scope has no tab stops or no content at all.

@return — true if focus moved.

Returns:

  • (Boolean) 


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# File 'lib/tuile/screen.rb', line 442

def focus_next = cycle_focus(forward: true)

#focus_previous ⇒ Boolean

Mirror of #focus_next that walks backwards through the tab order.

@return — true if focus moved.

Returns:

  • (Boolean) 


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# File 'lib/tuile/screen.rb', line 446

def focus_previous = cycle_focus(forward: false)

#handle_key(key) ⇒ Boolean

A key has been pressed on the keyboard. Handle it, or forward to active window.

Dispatch order:

1. Tab / Shift+Tab — reserved focus navigation, intercepted before
 anything else so a focused {Component::TextField} (which swallows
 printable keys) can't trap them.
2. App-level shortcuts from {#register_global_shortcut}. An entry
 registered with `over_popups: true` always fires; one with the
 default `over_popups: false` fires only when no modal popup is open
 (otherwise the modal popup receives the key normally). A non-modal
 overlay doesn't suppress global shortcuts.
3. {ScreenPane#handle_key} — delivery to {#focused}, bubbling up the
 focus chain to the scope root.

@param key

@return — true if the key was handled by some window.

Parameters:

  • key (String)

Returns:

  • (Boolean) 


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# File 'lib/tuile/screen.rb', line 833

def handle_key(key)
  case key
  when Keys::TAB
    focus_next
    true
  when Keys::SHIFT_TAB
    focus_previous
    true
  else
    shortcut = @global_shortcuts[key]
    if !shortcut.nil? && (shortcut.over_popups || @pane.modal_popup.nil?)
      shortcut.block.call
      true
    else
      @pane.handle_key(key)
    end
  end
end

#handle_mouse(event) ⇒ void

This method returns an undefined value.

Finds target window and calls Component::Window#handle_mouse.

@param event

Parameters:



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# File 'lib/tuile/screen.rb', line 855

def handle_mouse(event) = @pane.handle_mouse(event)

#handle_paste(text) ⇒ Boolean

Delivers pasted text down the focus chain (Tuile::ScreenPane#handle_paste).

Deliberately not the key ladder: a paste is not a keystroke, so it skips Tab traversal and the global-shortcut registry entirely and goes straight to delivery. Unhandled text is dropped — there is no fallback that replays it as keys, which would put back the very ambiguity mode 2004 exists to remove.

@param text

@return — true if some component consumed it.

Parameters:

  • text (String)

Returns:

  • (Boolean) 


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# File 'lib/tuile/screen.rb', line 866

def handle_paste(text) = @pane.handle_paste(text)

#has_popup?(window) ⇒ Boolean

Internal — use Component::Overlay#open? instead.

@param window — any overlay, modal or not.

@return — true if this overlay is currently mounted.

Parameters:

Returns:

  • (Boolean) 


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# File 'lib/tuile/screen.rb', line 541

def has_popup?(window) # rubocop:disable Naming/PredicatePrefix
  check_locked
  @pane.has_popup?(window)
end

#invalidate(component) ⇒ void

This method returns an undefined value.

Invalidates a component: causes the component to be repainted on next call to #repaint.

@param component

Parameters:



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# File 'lib/tuile/screen.rb', line 309

def invalidate(component)
  check_locked
  raise TypeError, "expected Component, got #{component.inspect}" unless component.is_a? Component

  @invalidated << component unless @repainting.include? component
end

#layout ⇒ void

This method returns an undefined value.

Resizes #buffer and #pane to the current #size, invalidates the whole tree and repaints. Run whenever the terminal size changes (the EventQueue::TTYSizeEvent path) and once at startup via the first #content=.



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# File 'lib/tuile/screen.rb', line 809

def layout
  check_locked
  @buffer.resize(size) unless @buffer.size == size
  needs_full_repaint
  @pane.rect = Rect.new(0, 0, size.width, size.height)
  repaint
end

#needs_full_repaint ⇒ void

This method returns an undefined value.

Invalidates the entire attached tree, forcing every component to repaint on the next cycle. Needed whenever something overdraws the scene without clipping and then exposes what was underneath — a closing popup (#remove_popup), or a popup that shrinks or moves so its new #rect no longer covers the cells it previously painted (Component::Overlay#rect=). The popup-only fast path in #repaint can't clear those vacated cells on its own, so we accept the cost of a full repaint.



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# File 'lib/tuile/screen.rb', line 533

def needs_full_repaint
  @pane&.on_tree { invalidate _1 }
end

#on_background_color(color) ⇒ void

This method returns an undefined value.

The re-probe answered: adopt the color and restyle, since an app's background-derived tints are now a scheme behind. Deliberately keeps the previous color until the reply lands rather than blanking it on the flip — a terminal that reports mode-2031 flips but not OSC 11 would otherwise lose the color it gave us at startup, permanently.

@param color

Parameters:



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# File 'lib/tuile/screen.rb', line 750

def on_background_color(color)
  return if @background_color == color

  @background_color = color
  @pane&.on_tree { _1.__send__(:on_theme_changed) }
  needs_full_repaint
end

#on_color_scheme(scheme) ⇒ void

This method returns an undefined value.

An OS appearance flip arrived (mode-2031 report): remember the scheme, apply the matching member of #theme_def, and re-probe for the new background RGB, which the report does not carry.

The query goes out from this thread — the event-loop thread, which also owns #emit — so its bytes can never land inside a frame's synchronized-output batch. The reply comes back through the key thread as an EventQueue::BackgroundColorEvent.

@param scheme — :dark or :light.

Parameters:

  • scheme (Symbol) 


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# File 'lib/tuile/screen.rb', line 737

def on_color_scheme(scheme)
  @color_scheme = scheme
  self.theme = @theme_def.for(@color_scheme)
  print TerminalBackground::QUERY
end

#popups ⇒ ::Array[Component::Overlay]

@return — the open overlay stack — both Component::Popup modals and bare Component::Overlays — in stacking order (forwarded to Tuile::ScreenPane). The array must not be modified!

Returns:



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# File 'lib/tuile/screen.rb', line 257

def popups = @pane.popups

#print(*args) ⇒ void

This method returns an undefined value.

Writes terminal-housekeeping escapes straight to stdout: #clear, mouse-tracking start/stop, the color-scheme notify toggles, the OSC 11 background re-probe, cursor-show on teardown. Component painting does not go through here anymore — it writes into #buffer, which #repaint diffs and #emits. FakeScreen overrides this (and #emit) to capture into @prints instead of the test runner's stdout.

Flushed, like #emit: none of these escapes ends in a newline, and a buffered stdout would hold a query — one whose reply the app is waiting on — until the next frame went out.

@param args — stuff to print.

Parameters:

  • args (String) 


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# File 'lib/tuile/screen.rb', line 597

def print(*args)
  Kernel.print(*args)
  $stdout.flush
end

#register_global_shortcut(key, over_popups: false, &block) ⇒ void

This method returns an undefined value.

Registers an app-level keyboard shortcut: when key arrives, the block runs on the event-loop thread (free to mutate UI) before the key reaches any component. Re-registering a key replaces its binding.

This registry is the only keyboard mechanism above the component tree, and nothing suppresses it — so it accepts only keys no widget can need. Three groups raise at registration rather than misbehaving at runtime:

  • Printable keys — they'd hijack typing into a Component::TextField. A scope-wide one-key binding belongs on the scope root's own handle_key, where a focused field consumes it first (see Tuile::ScreenPane#handle_key).

  • TAB / SHIFT_TAB — #handle_key intercepts them for focus navigation before the registry is consulted, so a binding would never fire.

  • EDITING_KEYS — ENTER, BACKSPACE, DELETE and the arrows, which every editable widget needs.

    screen.register_global_shortcut(Keys::CTRL_L, over_popups: true) do log_popup.open end

@param key — unprintable key (e.g. Keys::CTRL_L, Keys::ESC).

@param over_popups — when true, fires even while a modal popup is open (pre-empting the popup); when false (default), suppressed while any popup is open so the popup gets the key.

Parameters:

  • key (String)
  • over_popups: (Boolean) (defaults to: false) 


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# File 'lib/tuile/screen.rb', line 476

def register_global_shortcut(key, over_popups: false, &block)
  raise ArgumentError, "block required" if block.nil?
  raise ArgumentError, "key must be a String, got #{key.inspect}" unless key.is_a?(String)
  raise ArgumentError, "key cannot be empty" if key.empty?
  if Keys.printable?(key)
    raise ArgumentError,
          "global shortcut key must be unprintable; got #{key.inspect}. " \
          "For a one-key binding, override handle_key on the scope root " \
          "(your content layout, or the popup) — a focused text field then " \
          "consumes the key first, so typing isn't hijacked."
  end
  if [Keys::TAB, Keys::SHIFT_TAB].include?(key)
    raise ArgumentError,
          "#{key == Keys::TAB ? "TAB" : "SHIFT_TAB"} is reserved for focus navigation"
  end
  if EDITING_KEYS.include?(key)
    raise ArgumentError,
          "#{key.inspect} is reserved: every editable widget needs it, and this registry " \
          "sits above the component tree with nothing to suppress it. For a default " \
          "button, handle ENTER in the form's own handle_key instead — a focused " \
          "TextArea/TextField gets first refusal there."
  end
  @global_shortcuts[key] = Shortcut.new(block: block, over_popups: over_popups)
end

#remove_popup(window) ⇒ void

This method returns an undefined value.

Internal — use Component::Overlay#close instead. Removes the overlay from #pane, repairs focus, and repaints the scene.

Does nothing if the overlay is not open on this screen.

@param window — any overlay, modal or not.

Parameters:



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# File 'lib/tuile/screen.rb', line 516

def remove_popup(window)
  check_locked
  return unless @pane.has_popup?(window)

  @pane.remove_popup(window)
  needs_full_repaint
end

#repaint ⇒ void

This method returns an undefined value.

Repaints the screen; tries to be as effective as possible, by only considering invalidated components and flushing just the changed cells of #buffer. Called once per event-loop tick (on EventQueue::EmptyQueueEvent); components should Component#invalidate and let the loop coalesce rather than call this directly.



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# File 'lib/tuile/screen.rb', line 628

def repaint
  check_locked
  # This simple TUI framework doesn't support window clipping since tiled
  # windows are not expected to overlap. If there rarely is a popup, we
  # just repaint all windows in correct order — sure they will paint over
  # other windows, but if this is done in the right order, the final
  # drawing will look okay. Not the most effective algorithm, but very
  # simple and very fast in common cases.

  did_paint = false
  until @invalidated.empty?
    # Defensive filter: a component can become detached between enqueue
    # and drain (popup close, sibling removed mid-event-handling, focus
    # repair). Detached components have no place on the screen and must
    # never paint, even though Component#invalidate already gates them
    # out — this catches the case where attachment changed since.
    @invalidated.delete_if { |c| !c.attached? }
    break if @invalidated.empty?

    did_paint = true
    popups = @pane.popups

    # Build the repaint list in z-order, leaning on the tree itself rather
    # than a depth sort. The pane's pre-order traversal already orders the
    # tiled layer (the content subtree) parent-before-child; the popups are
    # the top layer and must paint last, so we collect the tiled layer first
    # and append popups rather than taking a single pane.on_tree walk.
    popup_members = Set.new
    popups.each { |p| p.on_tree { popup_members << _1 } }

    # Tiled layer: invalidated non-popup components, in tree order.
    repaint = []
    tiled_invalidated = false
    @pane.on_tree do |c|
      next if popup_members.include?(c)
      next unless @invalidated.include?(c)

      repaint << c
      tiled_invalidated = true
    end

    # Popups on top: a layer repaints whole whenever anything *beneath* it —
    # the tiled tree, or a lower popup — repaints, else just its invalidated
    # members. Layer-by-layer rather than one tiled_invalidated bool because
    # the drain loops: a lower popup's repaint cascade re-invalidates
    # children into the *next* iteration (its gap-clearing Layout wipes and
    # re-queues a button, say), and that iteration has no tiled repaint —
    # only the full re-assert of every layer above keeps the stacking order
    # true across iterations (screen_spec pins it with two overlapping
    # popups). Overdraw into the buffer is free (only net-visible cell
    # changes reach the terminal), so reasserting layers is cheap.
    below_repainted = tiled_invalidated
    popups.each do |p|
      layer_invalidated = false
      p.on_tree { |c| layer_invalidated ||= @invalidated.include?(c) }
      p.on_tree { |c| repaint << c if below_repainted || @invalidated.include?(c) }
      below_repainted ||= layer_invalidated
    end

    @repainting = repaint.to_set
    @invalidated.clear

    repaint.each(&:repaint)
    @repainting.clear
  end
  return unless did_paint

  # Flush only the changed cells, then reposition the cursor — all inside
  # one synchronized-output batch so the terminal composites it atomically.
  emit("#{Ansi::SYNC_BEGIN}#{@buffer.flush}#{cursor_sequence}#{Ansi::SYNC_END}")
end

#run_event_loop(capture_mouse: true, bracketed_paste: true) ⇒ void

This method returns an undefined value.

Runs the event loop on the calling thread, taking over stdin (raw mode, echo off): keys and mouse events are dispatched via #handle_key / #handle_mouse, and the loop repaints once per drained tick. Returns when q or ESC is pressed unhandled. Restores terminal state on exit.

For the duration this thread owns the UI (#state is :running); ownership reverts to the creating thread once it returns.

@param capture_mouse — when true (default), enables xterm mouse tracking so clicks and scroll wheel arrive as MouseEvents and feed Component#handle_mouse. When false, no tracking escape sequence is written: the terminal keeps its native click handling, which is what you want if the app benefits more from select-to-copy than from click-to-focus. Components' handle_mouse is simply never invoked from the loop in that mode (the terminal stops sending the bytes).

@param bracketed_paste — when true (default), enables DEC private mode 2004 so pasted text arrives whole, as Component#handle_paste, instead of as one keystroke per character — which is the only way a pasted line break can be told from a typed Enter. When false, a paste streams in as keys again and a component that gives ENTER a meaning fires it once per pasted line. Turn it off only for a terminal that mishandles the mode.

Parameters:

  • capture_mouse: (Boolean) (defaults to: true)
  • bracketed_paste: (Boolean) (defaults to: true) 


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# File 'lib/tuile/screen.rb', line 411

def run_event_loop(capture_mouse: true, bracketed_paste: true)
  raise Tuile::Error, "Screen is closed: cannot run the event loop" if @closed

  # The guard above stays outside the begin: teardown for a setup that never
  # happened restores echo on a non-TTY stdin, and the ENOTTY masks the
  # real error.
  begin
    $stdin.echo = false
    print MouseEvent.start_tracking if capture_mouse
    print Keys::BRACKETED_PASTE_ON if bracketed_paste
    # Follow OS light/dark flips live: terminals supporting mode 2031
    # push color-scheme reports that the key thread turns into
    # {EventQueue::ColorSchemeEvent}s.
    print TerminalBackground::NOTIFY_ON
    $stdin.raw do
      event_loop
    end
  ensure
    print TerminalBackground::NOTIFY_OFF
    print Keys::BRACKETED_PASTE_OFF if bracketed_paste
    print MouseEvent.stop_tracking if capture_mouse
    print TTY::Cursor.show
    $stdin.echo = true
  end
end

#state ⇒ Symbol

:idle covers both ends of the screen's life — before the first #run_event_loop and after it returns — and a screen may cycle :idle → :running → :idle repeatedly. :closed is terminal.

@return — :idle (no event loop running), :running (a #run_event_loop is in progress) or :closed (after #close).

Returns:

  • (Symbol) 


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# File 'lib/tuile/screen.rb', line 267

def state
  return :closed if @closed

  @event_queue.running? ? :running : :idle
end

#unregister_global_shortcut(key) ⇒ void

This method returns an undefined value.

Removes a shortcut previously installed by #register_global_shortcut. No-op if key was not registered.

@param key

Parameters:

  • key (String) 


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# File 'lib/tuile/screen.rb', line 505

def unregister_global_shortcut(key)
  @global_shortcuts.delete(key)
end