class InteractiveScrollArea

Interactice scroll area which scrolls and reprints the content in response to user pressing arrow keys.

Attributes

content[R]

height[RW]

scroll_area[RW]

width[RW]

Public Class Methods

new(width, height) click to toggle source

# File lib/terminal-scroll-area/interactive_scroll_area.rb, line 13
def initialize(width, height)
  @width = width
  @height = height

  @scroll_area = ScrollArea.new(@width, @height)

  @reader = TTY::Reader.new(interrupt: :exit)
  @reader.subscribe(self)
end

Public Instance Methods

add_line(line) click to toggle source

# File lib/terminal-scroll-area/interactive_scroll_area.rb, line 40
def add_line(line)
  @scroll_area.add_line(line)
end

add_string(string) click to toggle source

# File lib/terminal-scroll-area/interactive_scroll_area.rb, line 36
def add_string(string)
  @scroll_area.add_string(string)
end

content=(new_content) click to toggle source

# File lib/terminal-scroll-area/interactive_scroll_area.rb, line 32
def content=(new_content)
  @scroll_area.content = new_content
end

keydown(_event) click to toggle source

# File lib/terminal-scroll-area/interactive_scroll_area.rb, line 44
def keydown(_event)
  @scroll_area.scroll_down
  print_in_place(@scroll_area.render)
end

keyleft(_event) click to toggle source

# File lib/terminal-scroll-area/interactive_scroll_area.rb, line 59
def keyleft(_event)
  @scroll_area.scroll_left
  print_in_place(@scroll_area.render)
end

keyright(_event) click to toggle source

# File lib/terminal-scroll-area/interactive_scroll_area.rb, line 54
def keyright(_event)
  @scroll_area.scroll_right
  print_in_place(@scroll_area.render)
end

keyup(_event) click to toggle source

# File lib/terminal-scroll-area/interactive_scroll_area.rb, line 49
def keyup(_event)
  @scroll_area.scroll_up
  print_in_place(@scroll_area.render)
end

scroll() click to toggle source

# File lib/terminal-scroll-area/interactive_scroll_area.rb, line 23
def scroll
  print_in_place(@scroll_area.render)
  TTY::Cursor.invisible do
    loop do
      @reader.read_keypress
    end
  end
end

Private Instance Methods

print_in_place(text) click to toggle source

# File lib/terminal-scroll-area/interactive_scroll_area.rb, line 66
def print_in_place(text)
  cursor = TTY::Cursor

  # Scrolling down is needed if there are less lines under
  # the terminal prompt than the content height. Or else, clearing
  # lines upwards by the content height will remove the prompt as well.
  in_place = TTY::Cursor.scroll_down * (@height - 1)
  in_place << cursor.clear_lines(@height, :up)
  in_place << cursor.save
  in_place << text
  in_place << cursor.restore

  print(in_place)
end