Class: Tuile::Component::List::Cursor

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

Overview

Tracks cursor position within the list.

Defined Under Namespace

Classes: Limited, None

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(position: 0) ⇒ Cursor

@param position — the initial cursor position.

Parameters:

  • position: (Integer) (defaults to: 0) 


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# File 'lib/tuile/component/list.rb', line 292

def initialize(position: 0)
  raise "invalid position #{position}" unless position.is_a? Integer

  @position = position
end

Instance Attribute Details

#position ⇒ Integer (readonly)

@return — 0-based line index of the current cursor position.

Returns:

  • (Integer) 


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# File 'lib/tuile/component/list.rb', line 339

def position
  @position
end

Instance Method Details

#candidate_positions(line_count) ⇒ ::Array[Integer]

@param line_count — number of lines in the list.

@return — positions the cursor can land on, in ascending order.

Parameters:

  • line_count (Integer)

Returns:

  • (::Array[Integer]) 


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# File 'lib/tuile/component/list.rb', line 344

def candidate_positions(line_count)
  (0...line_count).to_a
end

#go(new_position) ⇒ Boolean

Moves the cursor to the new position. Public only because of testing.

@param new_position — new 0-based cursor position.

@return — true if the position changed.

Parameters:

  • new_position (Integer)

Returns:

  • (Boolean) 


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# File 'lib/tuile/component/list.rb', line 386

def go(new_position)
  new_position = new_position.clamp(0, nil)
  return false if @position == new_position

  @position = new_position
  true
end

#go_down_by(lines, line_count) ⇒ Boolean

@param lines

@param line_count

Parameters:

  • lines (Integer)
  • line_count (Integer)

Returns:

  • (Boolean) 


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# File 'lib/tuile/component/list.rb', line 408

def go_down_by(lines, line_count)
  go((@position + lines).clamp(nil, line_count - 1))
end

#go_to_first ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/tuile/component/list.rb', line 419

def go_to_first
  go(0)
end

#go_to_last(line_count) ⇒ Boolean

Moves the cursor to the last reachable position. For base Tuile::Component::List::Cursor, the last line; Limited clamps to the last allowed position; None is a no-op.

@param line_count — number of lines in the list.

@return — true if the position changed.

Parameters:

  • line_count (Integer)

Returns:

  • (Boolean) 


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# File 'lib/tuile/component/list.rb', line 399

def go_to_last(line_count)
  go(line_count - 1)
end

#go_up_by(lines) ⇒ Boolean

@param lines

Parameters:

  • lines (Integer)

Returns:

  • (Boolean) 


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# File 'lib/tuile/component/list.rb', line 414

def go_up_by(lines)
  go(@position - lines)
end

#handle_key(key, line_count, viewport_lines) ⇒ Boolean

@param key — pressed keyboard key.

@param line_count — number of lines in the list.

@param viewport_lines — number of visible lines.

@return — true if the cursor moved.

Parameters:

  • key (String)
  • line_count (Integer)
  • viewport_lines (Integer)

Returns:

  • (Boolean) 


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# File 'lib/tuile/component/list.rb', line 352

def handle_key(key, line_count, viewport_lines)
  case key
  when *Keys::DOWN_ARROWS
    go_down_by(1, line_count)
  when *Keys::UP_ARROWS
    go_up_by(1)
  when *Keys::HOMES
    go_to_first
  when *Keys::ENDS_
    go_to_last(line_count)
  when Keys::CTRL_U
    go_up_by(viewport_lines / 2)
  when Keys::CTRL_D
    go_down_by(viewport_lines / 2, line_count)
  else
    false
  end
end

#handle_mouse(line, event, line_count) ⇒ Boolean

@param line — cursor is hovering over this line.

@param event — the event.

@param line_count — number of lines in the list.

@return — true if the event was handled.

Parameters:

  • line (Integer)
  • event (MouseEvent)
  • line_count (Integer)

Returns:

  • (Boolean) 


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

def handle_mouse(line, event, line_count)
  if event.button == :left
    go(line.clamp(nil, line_count - 1))
  else
    false
  end
end