Class: Twterm::Tab::Scrollable::Scroller

Inherits:
Object
  • Object
show all
Extended by:
Forwardable
Defined in:
lib/twterm/tab/scrollable.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Scroller

Returns a new instance of Scroller.



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# File 'lib/twterm/tab/scrollable.rb', line 50

def initialize
  @index = 0
  @offset = 0
  @no_cursor_mode = false
end

Instance Attribute Details

#delegate ⇒ Object

Returns the value of attribute delegate.



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# File 'lib/twterm/tab/scrollable.rb', line 31

def delegate
  @delegate
end

#index ⇒ Object (readonly)

Returns the value of attribute index.



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# File 'lib/twterm/tab/scrollable.rb', line 29

def index
  @index
end

#offset ⇒ Object (readonly)

Returns the value of attribute offset.



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# File 'lib/twterm/tab/scrollable.rb', line 29

def offset
  @offset
end

Instance Method Details

#after_move(&block) ⇒ Object 



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# File 'lib/twterm/tab/scrollable.rb', line 34

def after_move(&block)
  add_hook(:after_move, &block)
end

#current_item ⇒ Object 



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# File 'lib/twterm/tab/scrollable.rb', line 38

def current_item
  items[index]
end

#current_item?(i) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/twterm/tab/scrollable.rb', line 42

def current_item?(i)
  index == offset + i
end

#drawable_items ⇒ Object 



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# File 'lib/twterm/tab/scrollable.rb', line 56

def drawable_items
  items.drop(offset).take(drawable_item_count)
end

#item_appended! ⇒ Object 



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# File 'lib/twterm/tab/scrollable.rb', line 60

def item_appended!
  @index -= 1
  @offset -= 1 if @offset > 0
end

#item_prepended! ⇒ Object 



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# File 'lib/twterm/tab/scrollable.rb', line 65

def item_prepended!
  @index += 1
  @offset += 1 unless @index < 4
  # keep cursor position unless it is on the top
end

#move_down ⇒ Object 



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# File 'lib/twterm/tab/scrollable.rb', line 71

def move_down
  return if count == 0 || index == count - 1
  # return when there are no items or cursor is at the bottom

  @index += 1
  @offset += 1 if (no_cursor_mode? || cursor_on_the_downside?) && !last_item_shown?

  hook :after_move
end

#move_to_bottom ⇒ Object 



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# File 'lib/twterm/tab/scrollable.rb', line 81

def move_to_bottom
  return if count == 0 || index == count - 1

  @index = count - 1
  @offset = [count - drawable_item_count + 1, 0].max

  @offset += 1 until last_item_shown?

  hook :after_move
end

#move_to_top ⇒ Object 



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# File 'lib/twterm/tab/scrollable.rb', line 92

def move_to_top
  return if count.zero? || index.zero?

  @index = 0
  @offset = 0

  hook :after_move
end

#move_up ⇒ Object 



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# File 'lib/twterm/tab/scrollable.rb', line 101

def move_up
  return if count.zero? || index.zero?

  @index -= 1
  @offset -= 1 if cursor_on_the_upside? && !first_item_shown?

  hook :after_move
end

#no_cursor_mode? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/twterm/tab/scrollable.rb', line 46

def no_cursor_mode?
  !!@no_cursor_mode
end

#nth_item_drawable?(n) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/twterm/tab/scrollable.rb', line 110

def nth_item_drawable?(n)
  n.between?(offset, offset + drawable_item_count)
end

#respond_to_key(key) ⇒ Object 



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# File 'lib/twterm/tab/scrollable.rb', line 114

def respond_to_key(key)
  case key
  when ?d, 4
    10.times { move_down }
  when ?g
    move_to_top
  when ?G
    move_to_bottom
  when ?j, 14, Curses::Key::DOWN
    move_down
  when ?k, 16, Curses::Key::UP
    move_up
  when ?u, 21
    10.times { move_up }
  else
    return false
  end

  true
end

#set_no_cursor_mode! ⇒ Object 



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# File 'lib/twterm/tab/scrollable.rb', line 135

def set_no_cursor_mode!
  @no_cursor_mode = true
end