Module: BumpsparkHelper

Included in:
TuneupHelper
Defined in:
lib/bumpspark_helper.rb

Overview

Note: This is a modified copy of _why’s ‘bumpspark’ library, discussed and collaborated on at:

http://redhanded.hobix.com/inspect/sparklinesForMinimalists.html

Many thanks to the various collaborators; _why (concept), MenTaLguY (transparency), and jzp (png)

Instance Method Summary collapse

Instance Method Details

#build_data_url(type, data) ⇒ Object 



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# File 'lib/bumpspark_helper.rb', line 37

def build_data_url(type,data)
  data = Base64.encode64(data).delete("\n")
  return "data:#{type};base64,#{CGI.escape(data)}" 
end

#build_png(image_rows) ⇒ Object 



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# File 'lib/bumpspark_helper.rb', line 15

def build_png(image_rows)
    header = [137, 80, 78, 71, 13, 10, 26, 10].pack("C*")
    raw_data = image_rows.map { |row| [0] + row }.flatten.pack("C*")
    ihdr_data = [   image_rows.first.length,image_rows.length,
                    8,2,0,0,0].pack("NNCCCCC")
    ihdr = build_png_chunk("IHDR", ihdr_data)
  trns = build_png_chunk("tRNS", ([ 0 ]*6).pack("C6"))
  idat = build_png_chunk("IDAT", Zlib::Deflate.deflate(raw_data))
    iend = build_png_chunk("IEND", "")

    return header + ihdr + trns + idat + iend
end

#build_png_chunk(type, data) ⇒ Object

:nodoc:



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# File 'lib/bumpspark_helper.rb', line 10

def build_png_chunk(type,data)
    to_check = type + data
    return [data.length].pack("N") + to_check + [Zlib.crc32(to_check)].pack("N")
end

#bumpspark(results) ⇒ Object 



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# File 'lib/bumpspark_helper.rb', line 27

def bumpspark(results)    
   black = [0, 0, 0]
   white, red, grey = [0xFF,0xFF,0xFF], [0xFF,0,0], [0x99,0x99,0x99]
   rows = normalize(results).inject([]) do |ary, r|
     ary << [black]*15 << [black]*15
       ary.last[r/9,4] = [(r > 50 and red or grey)]*4
       ary
   end.transpose.reverse
   return build_png(rows)
end

#normalize(results) ⇒ Object 



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# File 'lib/bumpspark_helper.rb', line 42

def normalize(results)
  min, max = results.min, results.max
  width = max - min
  return [1] * results.size if width == 0
  width += (300 * 1000)
  results.map do |result|
    ((result - min) * 100 / width.to_f).to_i
  end
end