Class: Tuile::Component::TextView

Inherits:
Tuile::Component show all
Defined in:
lib/tuile/component/text_view.rb

Overview

A read-only viewer for prose: chunks of formatted text that scroll vertically. Shape-wise a hybrid between Label (string-shaped content via #text=) and List (scroll keys, optional scrollbar, auto-scroll).

Text is modeled as a StyledString: embedded ‘n` are hard line breaks, lines wider than the viewport are word-wrapped via StyledString#wrap (style spans are preserved across wrap boundaries — unlike the older ANSI-as-bytes wrapping, color does not get dropped on continuation rows). #text= accepts a String (parsed via StyledString.parse, so embedded ANSI is honored) or a StyledString directly; #text always returns the StyledString.

For incremental updates pick the right primitive: #append (aliased as ‘<<`) is verbatim and stream-friendly — chunks are concatenated straight onto the buffer, with embedded `n` becoming hard breaks. #add_line is the “log entry” convenience — it starts the content on a fresh line by inserting a leading `n` when the buffer is non-empty. #remove_last_n_lines pops hard lines back off the tail — the inverse of building up a region with #append / #add_line, so a caller streaming reformattable content (e.g. partially-rendered Markdown that may need to retract its last paragraph) can replace the tail without rewriting the whole text. Turn on #auto_scroll to keep the latest content in view.

TextView is meant to be the content of a Window — focus indication and keyboard-hint surfacing rely on the surrounding window chrome.

Defined Under Namespace

Classes: Region

Instance Attribute Summary collapse

Attributes inherited from Tuile::Component

#key_shortcut, #on_theme_changed, #parent, #rect

Instance Method Summary collapse

Methods inherited from Tuile::Component

#active=, #active?, #attached?, #children, #cursor_position, #depth, #find_shortcut_component, #focus, #keyboard_hint, #on_child_content_size_changed, #on_child_removed, #on_focus, #on_tree, #root, #screen

Constructor Details

#initialize ⇒ TextView

Returns a new instance of TextView.



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# File 'lib/tuile/component/text_view.rb', line 32

def initialize
  super
  # Three parallel structures, kept in lockstep by every mutator:
  # `@hard_lines` is the logical model (one entry per `\n`-delimited
  # line, width-independent); `@physical_lines` is the rendered view
  # (each hard line word-wrapped to `wrap_width` and padded with
  # trailing blanks, so painting a row is a lookup); and
  # `@hard_line_wrap_counts` is an Integer-per-hard-line cache of
  # how many physical rows each hard line occupies, so a mid-buffer
  # splice can find its starting physical-row offset without
  # re-wrapping every preceding hard line.
  #
  # Invariants:
  # - `@hard_line_wrap_counts.size == @hard_lines.size`
  # - `@hard_line_wrap_counts.sum == @physical_lines.size`
  # A full rebuild ({#rewrap}) happens on {#text=} and width changes;
  # other mutators splice incrementally.
  @hard_lines = []
  @physical_lines = []
  @hard_line_wrap_counts = []
  @text = StyledString::EMPTY
  @blank_line = StyledString::EMPTY
  @top_line = 0
  @auto_scroll = false
  @follow = true
  @scrollbar_visibility = :gone
  # The view always has at least one region — an implicit default. It
  # owns whatever hard lines exist that no later region claims. App
  # code that never calls {#create_region} sees the same behavior as
  # before (a single region containing everything); apps that do call
  # {#create_region} stack additional regions at the spatial tail.
  @regions = [Region.send(:new, self)]
end

Instance Attribute Details

#auto_scroll ⇒ Boolean

Returns if true, mutating the text scrolls the viewport so the last line stays in view — but only while the viewport is already pinned to the last line (see #following?). Scroll up to read older content and appends stop yanking you back down; scroll back to the bottom and tailing resumes. Default ‘false`.

Returns:

  • (Boolean) —

    if true, mutating the text scrolls the viewport so the last line stays in view — but only while the viewport is already pinned to the last line (see #following?). Scroll up to read older content and appends stop yanking you back down; scroll back to the bottom and tailing resumes. Default ‘false`.



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# File 'lib/tuile/component/text_view.rb', line 88

def auto_scroll
  @auto_scroll
end

#content_size ⇒ Size (readonly)

Returns longest hard-line’s display width × number of hard lines. Reported on the unwrapped text — wrap-aware sizing would be circular (width depends on width). Empty text returns ‘Size.new(0, 0)`. Maintained incrementally by #text= and #append, so reads are O(1).

Returns:

  • (Size) —

    longest hard-line’s display width × number of hard lines. Reported on the unwrapped text — wrap-aware sizing would be circular (width depends on width). Empty text returns ‘Size.new(0, 0)`. Maintained incrementally by #text= and #append, so reads are O(1).



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# File 'lib/tuile/component/text_view.rb', line 394

def content_size
  @content_size
end

#scrollbar_visibility ⇒ Symbol

Returns ‘:gone` or `:visible`.

Returns:

  • (Symbol) —

    ‘:gone` or `:visible`.



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# File 'lib/tuile/component/text_view.rb', line 81

def scrollbar_visibility
  @scrollbar_visibility
end

#top_line ⇒ Integer

Returns index of the first visible physical line.

Returns:

  • (Integer) —

    index of the first visible physical line.



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# File 'lib/tuile/component/text_view.rb', line 78

def top_line
  @top_line
end

Instance Method Details

#<<(str) ⇒ self

Verbatim append, returning ‘self` for chainability (`view << a << b`).

Parameters:

Returns:

  • (self) 


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# File 'lib/tuile/component/text_view.rb', line 200

def <<(str)
  append(str)
  self
end

#add_line(str) ⇒ void

This method returns an undefined value.

Appends ‘str` as a new entry: starts a fresh hard line first (when the buffer is non-empty) and then appends `str`. Equivalent to `append(“n” + str)` on a non-empty buffer, or `append(str)` on an empty one. `nil` and `“”` produce a blank entry on a non-empty buffer and a no-op on an empty buffer (matches the old `append` semantics for “log line” callers).

Parameters:



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# File 'lib/tuile/component/text_view.rb', line 213

def add_line(str)
  parsed = StyledString.parse(str)
  if empty? || @regions.last.empty?
    # No previous line in the tail region to break away from — just
    # append. (If the tail region is empty but earlier regions have
    # content, the verbatim {#append} path already starts a fresh
    # hard line in the tail.)
    append(parsed)
  else
    append(StyledString.plain("\n") + parsed)
  end
end

#append(str) ⇒ void

This method returns an undefined value.

Appends ‘str` verbatim. Embedded `n` characters become hard line breaks; otherwise the text is concatenated onto the current last hard line. Designed for streaming use (e.g. an LLM chat window receiving partial messages — feed each chunk straight in). Accepts the same input forms as #text=; empty/`nil` input is a no-op.

For the “add an entry on a new line” pattern use #add_line.

Cost is O(appended + width-of-current-last-hard-line) — the previously last hard line is re-wrapped (because the extension may cause it to wrap differently), any additional hard lines created by embedded ‘n` are wrapped fresh. The cached #text is invalidated and rebuilt on demand.

Parameters:



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# File 'lib/tuile/component/text_view.rb', line 163

def append(str)
  screen.check_locked
  appended = StyledString.parse(str)
  return if appended.empty?

  tail_region = @regions.last
  tail_was_empty = tail_region.empty?
  new_segments = appended.lines
  width = wrap_width

  if tail_was_empty
    # An empty spatial-tail region (either a fresh buffer, or an empty
    # region the app created at the tail) means new content starts on
    # a fresh hard line — we must not extend the previous region's
    # last line.
    new_segments.each { |hl| push_hard_line(hl, width) }
    added = new_segments.size
  else
    extension = new_segments.first
    unless extension.empty?
      old_last = pop_hard_line
      push_hard_line(old_last + extension, width)
    end
    new_segments[1..].each { |hl| push_hard_line(hl, width) }
    added = new_segments.size - 1
  end

  tail_region.send(:line_count=, tail_region.line_count + added)
  @text = nil
  update_top_line_if_auto_scroll
  invalidate
  self.content_size = compute_content_size
end

#clear ⇒ void

This method returns an undefined value.

Clears the text. Equivalent to ‘text = “”`.



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# File 'lib/tuile/component/text_view.rb', line 347

def clear
  self.text = StyledString::EMPTY
end

#create_region ⇒ Region

Creates a new empty Region at the spatial tail of the document and returns its handle. Subsequent #append / #<< / #add_line calls route through this new region (since it is now the spatial tail). Earlier regions keep their content and their handles stay valid; their Tuile::Component::TextView::Region#range shifts as later regions grow.

Apps streaming logically-distinct sections (e.g. an LLM’s “thinking” vs. “assistant” output) create one region per section, hold the handles, and call ‘region.append` / `region.text=` directly when they need to grow or rewrite an earlier section.

Returns:



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# File 'lib/tuile/component/text_view.rb', line 139

def create_region
  region = Region.send(:new, self)
  @regions << region
  region
end

#empty? ⇒ Boolean

Returns true iff #text is empty (no hard lines).

Returns:

  • (Boolean) —

    true iff #text is empty (no hard lines).



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# File 'lib/tuile/component/text_view.rb', line 146

def empty? = @hard_lines.empty?

#focusable? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/tuile/component/text_view.rb', line 385

def focusable? = true

#following? ⇒ Boolean

Returns whether #auto_scroll is currently tailing. True while the viewport sits at the last line; flips to false the moment the user scrolls up, and back to true once they scroll to the bottom again. Only consulted when #auto_scroll is enabled.

Returns:

  • (Boolean) —

    whether #auto_scroll is currently tailing. True while the viewport sits at the last line; flips to false the moment the user scrolls up, and back to true once they scroll to the bottom again. Only consulted when #auto_scroll is enabled.



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# File 'lib/tuile/component/text_view.rb', line 94

def following? = @follow

#handle_key(key) ⇒ Boolean

Parameters:

  • key (String)

Returns:

  • (Boolean) 


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# File 'lib/tuile/component/text_view.rb', line 398

def handle_key(key)
  return false unless active?
  return true if super

  case key
  when *Keys::DOWN_ARROWS then move_top_line_by(1)
  when *Keys::UP_ARROWS   then move_top_line_by(-1)
  when Keys::PAGE_DOWN    then move_top_line_by(viewport_lines)
  when Keys::PAGE_UP      then move_top_line_by(-viewport_lines)
  when Keys::CTRL_D       then move_top_line_by(viewport_lines / 2)
  when Keys::CTRL_U       then move_top_line_by(-viewport_lines / 2)
  when *Keys::HOMES, "g"  then move_top_line_to(0)
  when *Keys::ENDS_, "G"  then move_top_line_to(top_line_max)
  else return false
  end
  true
end

#handle_mouse(event) ⇒ void

This method returns an undefined value.

Parameters:



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# File 'lib/tuile/component/text_view.rb', line 418

def handle_mouse(event)
  super
  case event.button
  when :scroll_down then move_top_line_by(4)
  when :scroll_up   then move_top_line_by(-4)
  end
end

#insert(at, str) ⇒ void

This method returns an undefined value.

Inserts ‘str` at hard-line index `at`. Equivalent to `replace(at…at, str)` — a no-removal splice that grows the buffer by the parsed line count. `at == hard-line count` is allowed and appends at the end; for that case #append / #add_line are usually more idiomatic.

Parameters:

  • at (Integer) —

    0-based hard-line index in ‘[0, hard-line count]`.

  • str (String, StyledString, nil) —

    content to insert.



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# File 'lib/tuile/component/text_view.rb', line 341

def insert(at, str)
  replace(at...at, str)
end

#remove_last_n_lines(n) ⇒ void

This method returns an undefined value.

Drops the last ‘n` hard lines from the buffer. The inverse of building up a tail region with #append / #add_line: a caller streaming partially-rendered content whose tail must occasionally be retracted (e.g. Markdown-to-ANSI where a new token reformats the table being built) can call `remove_last_n_lines(k)` followed by `append(new_tail)` to replace the damaged region in place.

‘n == 0` and the empty-buffer case are no-ops (no invalidation). `n >= hard-line count` empties the buffer.

Operates on **hard lines** (the ‘n`-delimited entries the buffer stores), not on wrapped physical rows — same granularity as #add_line. Cost is O(rendered-rows of the popped lines).

Parameters:

  • n (Integer) —

    number of hard lines to drop; must be >= 0.

Raises:

  • (TypeError) —

    if ‘n` isn’t an ‘Integer`.

  • (ArgumentError) —

    if ‘n` is negative.



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# File 'lib/tuile/component/text_view.rb', line 243

def remove_last_n_lines(n)
  raise TypeError, "expected Integer, got #{n.inspect}" unless n.is_a?(Integer)
  raise ArgumentError, "n must not be negative, got #{n}" if n.negative?

  screen.check_locked
  return if n.zero? || empty?

  to_drop = [n, @hard_lines.size].min
  to_drop.times { pop_hard_line }

  # Cascade-shrink regions from the spatial tail. The tail region
  # gives up lines first; if more are still owed (because the tail
  # was shorter than `to_drop`), earlier regions shrink in turn.
  remaining = to_drop
  @regions.reverse_each do |region|
    break if remaining.zero?

    take = [remaining, region.line_count].min
    region.send(:line_count=, region.line_count - take)
    remaining -= take
  end

  @text = nil
  @top_line = top_line_max if @top_line > top_line_max
  update_top_line_if_auto_scroll
  invalidate
  self.content_size = compute_content_size
end

#repaint ⇒ void

This method returns an undefined value.

Paints the text into Tuile::Component#rect.

Skips the Tuile::Component#repaint default’s auto-clear: every row is painted explicitly (with padded blanks past the last line), so the “fully draw over your rect” contract is met without an upfront wipe.



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# File 'lib/tuile/component/text_view.rb', line 432

def repaint
  return if rect.empty?

  scrollbar = if scrollbar_visible?
                VerticalScrollBar.new(rect.height, line_count: @physical_lines.size, top_line: @top_line)
              end
  (0...rect.height).each do |row|
    line = paintable_line(row + @top_line, row, scrollbar)
    screen.print TTY::Cursor.move_to(rect.left, rect.top + row), line
  end
end

#replace(range, str) ⇒ void

This method returns an undefined value.

Replaces a contiguous range of hard lines with the parsed content of ‘str`. The replacement is parsed exactly like #text= and #append: a String is run through StyledString.parse (so embedded ANSI is honored), a StyledString is used as-is, `nil` behaves like an empty replacement (the range is deleted). Embedded `“n”` in the replacement produces multiple hard lines, so a single `replace` can grow or shrink the buffer.

‘range` selects which hard lines to swap out:

  • an ‘Integer` `n` is shorthand for `n..n` (replace one existing line — `n` must be in `[0, hard-line count)`);

  • a non-empty ‘Range` of hard-line indices replaces those lines;

  • an empty ‘Range` (e.g. `2…2`, or the canonical end-insertion `hard_lines.size…hard_lines.size`) is insertion at that position — no lines are removed. #insert is a thin alias for this case.

Endpoints must be non-negative integers; ‘begin` may equal `hard-line count` (insertion at the end), `end` may not exceed `hard-line count - 1`. `nil` endpoints (beginless / endless ranges) are not accepted.

Cost is roughly ‘O(from + length + new content)`: the splice updates only the affected slice of the physical-row buffer, using the per-hard-line wrap-count cache to locate the starting offset without re-wrapping preceding lines. Lines outside the splice are never re-wrapped. #top_line is clamped if the new line count puts it past the end; #auto_scroll pins it to the bottom as usual. The call is a no-op (no invalidation) when the parsed replacement equals the covered range (vacuously true for an empty range plus empty replacement, so `replace(n…n, “”)` is a cheap no-op).

Parameters:

  • range (Range, Integer) —

    hard-line indices to replace.

  • str (String, StyledString, nil) —

    replacement content.

Raises:

  • (TypeError) —

    if ‘range` is neither an `Integer` nor a `Range`, or if a `Range` endpoint is not an `Integer`, or if `str` is not a `String`, `StyledString`, or `nil`.

  • (ArgumentError) —

    if ‘range` has a negative endpoint, extends past the last hard line, or is malformed (`end` more than one below `begin`).



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# File 'lib/tuile/component/text_view.rb', line 315

def replace(range, str)
  screen.check_locked
  from, to = normalize_replace_range(range)

  parsed = StyledString.parse(str)
  new_hard_lines = parsed.empty? ? [] : parsed.lines
  length = to - from + 1
  return if new_hard_lines == @hard_lines[from, length]

  splice_hard_lines(from, length, new_hard_lines)
  update_region_counts(from, length, new_hard_lines.size)
  @text = nil
  @top_line = top_line_max if @top_line > top_line_max
  update_top_line_if_auto_scroll
  invalidate
  self.content_size = compute_content_size
end

#tab_stop? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/tuile/component/text_view.rb', line 387

def tab_stop? = true

#text ⇒ StyledString

Returns the current text. Defaults to an empty StyledString. Internally the text is stored as an array of hard lines so #append can stay O(appended) instead of re-scanning the whole buffer; the joined StyledString returned here is reconstructed on first read after a mutation and cached, so repeated reads are O(1) but the first read after #append pays O(total spans).

Returns:

  • (StyledString) —

    the current text. Defaults to an empty StyledString. Internally the text is stored as an array of hard lines so #append can stay O(appended) instead of re-scanning the whole buffer; the joined StyledString returned here is reconstructed on first read after a mutation and cached, so repeated reads are O(1) but the first read after #append pays O(total spans).



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# File 'lib/tuile/component/text_view.rb', line 73

def text
  @text ||= build_text
end

#text=(value) ⇒ void

This method returns an undefined value.

Replaces the text. Embedded ‘n` characters become hard line breaks. A `String` is parsed via StyledString.parse (so embedded ANSI is honored); a `StyledString` is used as-is; `nil` is coerced to an empty StyledString.

Detaches every existing Region (including the original default) and installs a fresh internal default region that owns all the new hard lines. Any handle the caller was holding becomes detached and raises on use — see Tuile::Component::TextView::Region#attached?. The no-op short-circuit (matching value, same StyledString) preserves existing regions.

Parameters:



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# File 'lib/tuile/component/text_view.rb', line 108

def text=(value)
  new_text = StyledString.parse(value)
  content_unchanged = text == new_text

  # `text=` is a structural reset: even when the new content matches
  # the old, existing region handles must die — the caller said "set
  # the text," not "merge with what's there." The unchanged-content
  # path still skips the expensive rewrap / invalidate work.
  @text = new_text
  @hard_lines = new_text.empty? ? [] : new_text.lines
  @regions.each { |r| r.send(:detach!) }
  @regions = [Region.send(:new, self, @hard_lines.size)]
  return if content_unchanged

  rewrap
  update_top_line_if_auto_scroll
  invalidate
  self.content_size = compute_content_size
end