Class: Castaway::Timeline

Inherits:
Object
  • Object
show all
Defined in:
lib/castaway/timeline.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(resolution, fps) ⇒ Timeline

Returns a new instance of Timeline.



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# File 'lib/castaway/timeline.rb', line 9

def initialize(resolution, fps)
  @resolution = resolution
  @elements = []
  @fps = fps

  @cached_command = nil
  @cached_file = nil
end

Instance Attribute Details

#fps ⇒ Object (readonly)

Returns the value of attribute fps.



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# File 'lib/castaway/timeline.rb', line 7

def fps
  @fps
end

#resolution ⇒ Object (readonly)

Returns the value of attribute resolution.



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# File 'lib/castaway/timeline.rb', line 7

def resolution
  @resolution
end

Instance Method Details

#_link(old, new) ⇒ Object 



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# File 'lib/castaway/timeline.rb', line 60

def _link(old, new)
  # FIXME: detect whether linking is supported, and fallback to copy
  # if not.

  FileUtils.ln(old, new)
end

#_log(frame, t, msg) ⇒ Object 



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# File 'lib/castaway/timeline.rb', line 75

def _log(frame, t, msg)
  _logger.info { format('[%d:%.2fs] %s', frame, t, msg) }
end

#_logger ⇒ Object 



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# File 'lib/castaway/timeline.rb', line 67

def _logger
  @_logger ||= Logger.new('build.log').tap do |logger|
    logger.formatter = lambda do |severity, _datetime, _progname, msg|
      "#{severity}: #{msg}\n"
    end
  end
end

#add(element) ⇒ Object 



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# File 'lib/castaway/timeline.rb', line 18

def add(element)
  @elements << element
end

#duration ⇒ Object 



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# File 'lib/castaway/timeline.rb', line 22

def duration
  @elements.map(&:t2).max
end

#render_frame(frame, name: 'frame') ⇒ Object 



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# File 'lib/castaway/timeline.rb', line 26

def render_frame(frame, name: 'frame')
  t = frame / fps.to_f

  signature = nil
  tool = MiniMagick::Tool::Convert.new.tap do |convert|
    convert << '-size' << resolution.to_geometry
    convert.xc 'black'

    @elements.sort_by(&:t1).each do |element|
      next unless element.alive_at?(t)
      element.render_at(t, convert)
    end

    convert.colorspace 'sRGB'
    convert.type 'TrueColor'
    convert.depth '16'

    signature = convert.command
    convert << "PNG48:#{name}.png"
  end

  if signature != @cached_command
    _log frame, t, tool.command.join(' ')
    @cached_command = signature
    @cached_file = name
    tool.call
  else
    old = "#{@cached_file}.png"
    new = "#{name}.png"
    _log frame, t, "duplicate #{old} as #{new}"
    _link old, new
  end
end