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, #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_removed, #on_focus, #on_tree, #root, #screen

Constructor Details

#initialize ⇒ TextView

Returns a new instance of TextView.



32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
 
# 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
  @content_size = Size::ZERO
  @blank_line = StyledString::EMPTY
  @top_line = 0
  @auto_scroll = false
  @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. Default ‘false`.

Returns:

  • (Boolean) —

    if true, mutating the text scrolls the viewport so the last line stays in view. Default ‘false`.



85
86
87
 
# File 'lib/tuile/component/text_view.rb', line 85

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).



382
383
384
 
# File 'lib/tuile/component/text_view.rb', line 382

def content_size
  @content_size
end

#scrollbar_visibility ⇒ Symbol

Returns ‘:gone` or `:visible`.

Returns:

  • (Symbol) —

    ‘:gone` or `:visible`.



81
82
83
 
# 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.



78
79
80
 
# 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) 


191
192
193
194
 
# File 'lib/tuile/component/text_view.rb', line 191

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:



204
205
206
207
208
209
210
211
212
213
214
215
 
# File 'lib/tuile/component/text_view.rb', line 204

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:



154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
 
# File 'lib/tuile/component/text_view.rb', line 154

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
  @content_size = compute_content_size
  update_top_line_if_auto_scroll
  invalidate
end

#clear ⇒ void

This method returns an undefined value.

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



338
339
340
 
# File 'lib/tuile/component/text_view.rb', line 338

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:



130
131
132
133
134
 
# File 'lib/tuile/component/text_view.rb', line 130

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).



137
 
# File 'lib/tuile/component/text_view.rb', line 137

def empty? = @hard_lines.empty?

#focusable? ⇒ Boolean

Returns:

  • (Boolean) 


373
 
# File 'lib/tuile/component/text_view.rb', line 373

def focusable? = true

#handle_key(key) ⇒ Boolean

Parameters:

  • key (String)

Returns:

  • (Boolean) 


386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
 
# File 'lib/tuile/component/text_view.rb', line 386

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:



406
407
408
409
410
411
412
 
# File 'lib/tuile/component/text_view.rb', line 406

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.



332
333
334
 
# File 'lib/tuile/component/text_view.rb', line 332

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.



234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
 
# File 'lib/tuile/component/text_view.rb', line 234

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
  @content_size = compute_content_size
  @top_line = top_line_max if @top_line > top_line_max
  update_top_line_if_auto_scroll
  invalidate
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.



420
421
422
423
424
425
426
427
428
429
430
 
# File 'lib/tuile/component/text_view.rb', line 420

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`).



306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
 
# File 'lib/tuile/component/text_view.rb', line 306

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
  @content_size = compute_content_size
  @top_line = top_line_max if @top_line > top_line_max
  update_top_line_if_auto_scroll
  invalidate
end

#tab_stop? ⇒ Boolean

Returns:

  • (Boolean) 


375
 
# File 'lib/tuile/component/text_view.rb', line 375

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).



73
74
75
 
# 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:



99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
 
# File 'lib/tuile/component/text_view.rb', line 99

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

  @content_size = compute_content_size
  rewrap
  update_top_line_if_auto_scroll
  invalidate
end