Class: TuiTui::ScrollList

Inherits:
Object
  • Object
show all
Defined in:
lib/tui_tui/scroll_list.rb

Overview

Cursor and viewport arithmetic shared by list-like widgets.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(count = 0) ⇒ ScrollList

Returns a new instance of ScrollList.



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# File 'lib/tui_tui/scroll_list.rb', line 8

def initialize(count = 0)
  @count = count
  @cursor = 0
  @top = 0
end

Instance Attribute Details

#count ⇒ Object

Returns the value of attribute count.



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# File 'lib/tui_tui/scroll_list.rb', line 19

def count
  @count
end

#cursor ⇒ Object (readonly)

Returns the value of attribute cursor.



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# File 'lib/tui_tui/scroll_list.rb', line 6

def cursor
  @cursor
end

#top ⇒ Object (readonly)

Returns the value of attribute top.



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# File 'lib/tui_tui/scroll_list.rb', line 6

def top
  @top
end

Instance Method Details

#at_end? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/tui_tui/scroll_list.rb', line 23

def at_end? = @cursor == last

#each_visible(height) ⇒ Object 



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# File 'lib/tui_tui/scroll_list.rb', line 44

def each_visible(height)
  return enum_for(:each_visible, height) unless block_given?

  height.times do |offset|
    index = @top + offset
    break if index >= @count

    yield index, offset
  end

  self
end

#empty? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/tui_tui/scroll_list.rb', line 21

def empty? = @count.zero?

#ensure_visible(height) ⇒ Object 



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# File 'lib/tui_tui/scroll_list.rb', line 35

def ensure_visible(height)
  return self if height <= 0

  @top = @cursor if @cursor < @top
  @top = @cursor - height + 1 if @cursor >= @top + height
  @top = 0 if @top.negative?
  self
end

#go_to(index) ⇒ Object 



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# File 'lib/tui_tui/scroll_list.rb', line 30

def go_to(index)
  @cursor = index.clamp(0, last)
  self
end

#last ⇒ Object 



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# File 'lib/tui_tui/scroll_list.rb', line 22

def last = [@count - 1, 0].max

#move(delta) ⇒ Object 



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# File 'lib/tui_tui/scroll_list.rb', line 25

def move(delta) = go_to(@cursor + delta)

#page(height) ⇒ Object 



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# File 'lib/tui_tui/scroll_list.rb', line 26

def page(height) = move(height)

#to_end ⇒ Object 



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# File 'lib/tui_tui/scroll_list.rb', line 28

def to_end = go_to(last)

#to_top ⇒ Object 



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# File 'lib/tui_tui/scroll_list.rb', line 27

def to_top = go_to(0)