Class: Net::RFB::FrameBuffer

Inherits:
Object
  • Object
show all
Defined in:
lib/net/rfb/frame_buffer.rb

Overview

Manage FrameBuffer pixel data for RFB protocol This is a little wrapper for the ‘Proxy` class in vncrec-ruby github.com/d-theus/vncrec-ruby

Defined Under Namespace

Classes: VNCRecAuthStub

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(io, w, h, bpp, encodings = nil) ⇒ FrameBuffer

Returns a new instance of FrameBuffer.

Parameters:

  • io (IO, #read, #sysread, #syswrite, #read_nonblock) —

    string stream from VNC server.

  • w (Integer) —

    width of the screen area

  • h (Integer) —

    height of the screen area

  • bpp (Symbol) —

    bits per pixel (BGR8 or BGRA)

  • encodings (Array<Symbol>) (defaults to: nil) —

    encoding (RAW or HEXTILE or ZRLE) default: RAW



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# File 'lib/net/rfb/frame_buffer.rb', line 17

def initialize(io, w, h, bpp, encodings = nil)
  @cb_mutex = Monitor.new
  @cb_cv = @cb_mutex.new_cond

  @encodings = encodings

  @vnc_rec_pix_fmt = convert_to_vnc_rec_pix_fmt bpp

  @proxy = VNCRec::RFB::Proxy.new(io, nil, nil, nil, [VNCRecAuthStub, nil])
  @proxy.prepare_framebuffer w, h, @vnc_rec_pix_fmt[:bpp]
end

Class Method Details

.convert_raw_pixel_data_to_rgba(px, pix_fmt) ⇒ Array<Integer>

convert raw pixel data to 32bit RGBA values according to VNC pixel format

Parameters:

  • px (String) —

    binary pixel data

  • pix_fmt (String) —

    pixel format (bgra, bgr8)

Returns:

  • (Array<Integer>) —

    array of 32bit pixel data



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# File 'lib/net/rfb/frame_buffer.rb', line 57

def self.convert_raw_pixel_data_to_rgba(px, pix_fmt)
  # see https://github.com/d-theus/vncrec-ruby/blob/master/lib/vncrec/constants.rb
  case pix_fmt.to_s
  when 'bgra'
    # convert 32bit BGRA -> 32bit RGBA
    px = px.unpack('V*')
    px.map! { |p| (p << 8) | 0xff }
  when 'bgr8'
    # convert 8bit BGR -> 32bit RGBA
    px = px.unpack('C*')
    px.map! do |p|
      r = (p & 0b00000111)
      g = (p & 0b00111000) >> 3
      b = (p & 0b11000000) >> 6
      ((r * 36) << 24) | ((g * 36) << 16) | ((b * 85) << 8) | 0xff
    end
  else
    raise "unknown pixel format #{pix_fmt.inspect}"
  end
end

Instance Method Details

#handle_response(t) ⇒ Object 



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# File 'lib/net/rfb/frame_buffer.rb', line 112

def handle_response(t)
  case t
  when 0 # ----------------------------------------------- FramebufferUpdate
    ret = handle_fb_update
    @cb_mutex.synchronize do
      @cb_cv.broadcast
    end
    ret
  when 1 # --------------------------------------------- SetColourMapEntries
    handle_set_colormap_entries
  end
end

#pixel_data ⇒ Object

raw pixel data of screen



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# File 'lib/net/rfb/frame_buffer.rb', line 41

def pixel_data
  @proxy.data
end

#request_update_fb(incremental: true, x: nil, y: nil, w: nil, h: nil, wait_for_response: false) ⇒ Object

Send request for update framebuffer.

if block given, called it with pixel data after the response received.

Parameters:

  • incremental (Boolean) (defaults to: true) —

    incremental, request just difference between previous and current framebuffer state.

  • x (Integer) (defaults to: nil)
  • y (Integer) (defaults to: nil)
  • w (Integer) (defaults to: nil)
  • h (Integer) (defaults to: nil)
  • wait_for_response (Boolean) (defaults to: false) —

    if true, wait for a FramebufferUpdate response



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# File 'lib/net/rfb/frame_buffer.rb', line 104

def request_update_fb(incremental: true, x: nil, y: nil, w: nil, h: nil, wait_for_response: false)
  @cb_mutex.synchronize do
    @proxy.fb_update_request incremental ? 1 : 0, x || 0, y || 0, w || @proxy.w, h || @proxy.h

    @cb_cv.wait if wait_for_response
  end
end

#rgba_pixel_data ⇒ Object

32bit RGBA pixel data of screen



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# File 'lib/net/rfb/frame_buffer.rb', line 46

def rgba_pixel_data
  px = pixel_data
  raise 'Error in get raw pixel_data.' unless px

  self.class.convert_raw_pixel_data_to_rgba px, @vnc_rec_pix_fmt[:string]
end

#save_pixel_data_as_png(dest = nil) ⇒ String

save current screen pixel data as PNG image

Parameters:

  • dest (String|IO|nil) (defaults to: nil) —

    destination file path, or IO-object, or nil

Returns:

  • (String) —

    PNG binary data as string when dest is null

    true

    else case



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# File 'lib/net/rfb/frame_buffer.rb', line 129

def save_pixel_data_as_png(dest = nil)
  request_update_fb(wait_for_response: true)

  image = ChunkyPNG::Image.new(@proxy.w, @proxy.h, rgba_pixel_data)

  if dest.is_a? IO
    # write to IO-object
    image.write dest
  elsif dest.is_a?(String) || dest.is_a?(Pathname)
    # write to file
    image.save dest.to_s
  elsif dest.nil?
    # return binary data as string
    return image.to_blob
  else
    raise ArgumentError, "Unsupported destination type #{dest.inspect}"
  end
  true
end

#send_initial_data ⇒ Object 



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# File 'lib/net/rfb/frame_buffer.rb', line 29

def send_initial_data
  # set encoding
  raise 'Error while setting encoding' unless set_encodings @encodings

  # set pixel format
  set_pixel_format @vnc_rec_pix_fmt

  # request all pixel data
  request_update_fb incremental: false
end

#set_encodings(*encodings) ⇒ Object

Set way of encoding video frames.

Parameters:

  • encodings (Symbol|String) —

    list of encoding of video data used to transfer.

    • :RAW

    • :HEXTILE

    • :ZRLE



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# File 'lib/net/rfb/frame_buffer.rb', line 91

def set_encodings(*encodings)
  @proxy.set_encodings [encodings].flatten.compact.map { |sym| VNCRec.const_get "ENC_#{sym}" }
end

#set_pixel_format(format) ⇒ Object

Set a way that server should use to represent pixel data

Parameters:

  • pixel (Symbol|String) —

    format:

    • :BGR8

    • :BGRA



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# File 'lib/net/rfb/frame_buffer.rb', line 82

def set_pixel_format(format)
  @proxy.set_pixel_format convert_to_vnc_rec_pix_fmt(format)
end