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 375

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 item index of the current cursor position.

Returns:

  • (Integer) 


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# File 'lib/tuile/component/list.rb', line 422

def position
  @position
end

Instance Method Details

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

@param item_count — number of items in the list.

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

Parameters:

  • item_count (Integer)

Returns:

  • (::Array[Integer]) 


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# File 'lib/tuile/component/list.rb', line 427

def candidate_positions(item_count)
  (0...item_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 469

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(count, item_count) ⇒ Boolean

@param count

@param item_count

Parameters:

  • count (Integer)
  • item_count (Integer)

Returns:

  • (Boolean) 


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# File 'lib/tuile/component/list.rb', line 491

def go_down_by(count, item_count)
  go((@position + count).clamp(nil, item_count - 1))
end

#go_to_first ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/tuile/component/list.rb', line 502

def go_to_first
  go(0)
end

#go_to_last(item_count) ⇒ Boolean

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

@param item_count — number of items in the list.

@return — true if the position changed.

Parameters:

  • item_count (Integer)

Returns:

  • (Boolean) 


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# File 'lib/tuile/component/list.rb', line 482

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

#go_up_by(count) ⇒ Boolean

@param count

Parameters:

  • count (Integer)

Returns:

  • (Boolean) 


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# File 'lib/tuile/component/list.rb', line 497

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

#handle_key?(key, item_count, viewport_rows) ⇒ Boolean

@param key — pressed keyboard key.

@param item_count — number of items in the list.

@param viewport_rows — number of visible rows.

@return — true if the cursor moved.

Parameters:

  • key (String)
  • item_count (Integer)
  • viewport_rows (Integer)

Returns:

  • (Boolean) 


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# File 'lib/tuile/component/list.rb', line 435

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

#handle_mouse_down?(item_index, event, item_count) ⇒ Boolean

@param item_index — the item pressed on.

@param event — the event.

@param item_count — number of items in the list.

@return — true if the cursor moved.

Parameters:

Returns:

  • (Boolean) 


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# File 'lib/tuile/component/list.rb', line 458

def handle_mouse_down?(item_index, event, item_count)
  if event.button == :left
    go(item_index.clamp(nil, item_count - 1))
  else
    false
  end
end