347 lines
8.0 KiB
Ruby
347 lines
8.0 KiB
Ruby
# frozen_string_literal: true
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class LetterAvatar
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class Identity
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attr_accessor :color, :letter
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def self.from_username(username)
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identity = new
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identity.color = LetterAvatar::COLORS[
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Digest::MD5.hexdigest(username)[0...15].to_i(16) % LetterAvatar::COLORS.length
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]
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identity.letter = username[0].upcase
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identity
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end
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end
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# BUMP UP if avatar algorithm changes
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VERSION = 5
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# CHANGE these values to support more pixel ratios
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FULLSIZE = 120 * 3
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POINTSIZE = 280
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class << self
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def version
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"#{VERSION}_#{image_magick_version}"
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end
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def cache_path
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"tmp/letter_avatars/#{version}"
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end
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def generate(username, size, opts = nil)
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DistributedMutex.synchronize("letter_avatar_#{version}_#{username}") do
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identity = (opts && opts[:identity]) || LetterAvatar::Identity.from_username(username)
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cache = true
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cache = false if opts && opts[:cache] == false
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size = FULLSIZE if size > FULLSIZE
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filename = cached_path(identity, size)
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return filename if cache && File.exists?(filename)
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fullsize = fullsize_path(identity)
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generate_fullsize(identity) if !cache || !File.exists?(fullsize)
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# Optimizing here is dubious, it can save up to 2x for large images (eg 359px)
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# BUT... we are talking 2400 bytes down to 1200 bytes, both fit in one packet
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# The cost of this is huge, its a 40% perf hit
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OptimizedImage.resize(fullsize, filename, size, size)
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filename
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end
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end
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def cached_path(identity, size)
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dir = "#{cache_path}/#{identity.letter}/#{identity.color.join("_")}"
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FileUtils.mkdir_p(dir)
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File.expand_path "#{dir}/#{size}.png"
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end
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def fullsize_path(identity)
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File.expand_path cached_path(identity, FULLSIZE)
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end
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def generate_fullsize(identity)
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color = identity.color
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letter = identity.letter
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filename = fullsize_path(identity)
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instructions = %W{
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-size #{FULLSIZE}x#{FULLSIZE}
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xc:#{to_rgb(color)}
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-pointsize #{POINTSIZE}
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-fill #FFFFFFCC
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-font Helvetica
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-gravity Center
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-annotate -0+26 #{letter}
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-depth 8
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#{filename}
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}
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Discourse::Utils.execute_command('convert', *instructions)
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## do not optimize image, it will end up larger than original
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filename
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end
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def to_rgb(color)
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r, g, b = color
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"rgb(#{r},#{g},#{b})"
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end
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def image_magick_version
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@image_magick_version ||=
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begin
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Thread.new do
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sleep 2
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cleanup_old
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end
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Digest::MD5.hexdigest(`convert --version` << `convert -list font`)
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end
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end
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def cleanup_old
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begin
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skip = File.basename(cache_path)
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parent_path = File.dirname(cache_path)
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Dir.entries(parent_path).each do |path|
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unless ['.', '..'].include?(path) || path == skip
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FileUtils.rm_rf(parent_path + "/" + path)
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end
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end
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rescue Errno::ENOENT
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# no worries, folder doesn't exists
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end
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end
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end
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# palette of optimally disctinct colors
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# cf. http://tools.medialab.sciences-po.fr/iwanthue/index.php
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# parameters used:
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# - H: 0 - 360
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# - C: 0 - 2
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# - L: 0.75 - 1.5
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COLORS = [[198, 125, 40],
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[61, 155, 243],
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[74, 243, 75],
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[238, 89, 166],
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[52, 240, 224],
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[177, 156, 155],
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[240, 120, 145],
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[111, 154, 78],
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[237, 179, 245],
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[237, 101, 95],
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[89, 239, 155],
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[43, 254, 70],
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[163, 212, 245],
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[65, 152, 142],
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[165, 135, 246],
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[181, 166, 38],
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[187, 229, 206],
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[77, 164, 25],
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[179, 246, 101],
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[234, 93, 37],
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[225, 155, 115],
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[142, 140, 188],
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[223, 120, 140],
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[249, 174, 27],
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[244, 117, 225],
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[137, 141, 102],
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[75, 191, 146],
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[188, 239, 142],
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[164, 199, 145],
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[173, 120, 149],
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[59, 195, 89],
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[222, 198, 220],
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[68, 145, 187],
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[236, 204, 179],
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[159, 195, 72],
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[188, 121, 189],
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[166, 160, 85],
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[181, 233, 37],
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[236, 177, 85],
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[121, 147, 160],
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[234, 218, 110],
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[241, 157, 191],
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[62, 200, 234],
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[133, 243, 34],
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[88, 149, 110],
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[59, 228, 248],
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[183, 119, 118],
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[251, 195, 45],
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[113, 196, 122],
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[197, 115, 70],
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[80, 175, 187],
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[103, 231, 238],
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[240, 72, 133],
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[228, 149, 241],
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[180, 188, 159],
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[172, 132, 85],
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[180, 135, 251],
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[236, 194, 58],
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[217, 176, 109],
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[88, 244, 199],
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[186, 157, 239],
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[113, 230, 96],
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[206, 115, 165],
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[244, 178, 163],
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[230, 139, 26],
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[241, 125, 89],
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[83, 160, 66],
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[107, 190, 166],
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[197, 161, 210],
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[198, 203, 245],
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[238, 117, 19],
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[228, 119, 116],
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[131, 156, 41],
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[145, 178, 168],
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[139, 170, 220],
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[233, 95, 125],
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[87, 178, 230],
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[157, 200, 119],
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[237, 140, 76],
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[229, 185, 186],
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[144, 206, 212],
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[236, 209, 158],
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[185, 189, 79],
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[34, 208, 66],
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[84, 238, 129],
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[133, 140, 134],
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[67, 157, 94],
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[168, 179, 25],
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[140, 145, 240],
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[151, 241, 125],
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[67, 162, 107],
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[200, 156, 21],
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[169, 173, 189],
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[226, 116, 189],
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[133, 231, 191],
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[194, 161, 63],
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[241, 77, 99],
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[241, 217, 53],
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[123, 204, 105],
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[210, 201, 119],
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[229, 108, 155],
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[240, 91, 72],
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[187, 115, 210],
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[240, 163, 100],
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[178, 217, 57],
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[179, 135, 116],
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[204, 211, 24],
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[186, 135, 57],
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[223, 176, 135],
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[204, 148, 151],
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[116, 223, 50],
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[95, 195, 46],
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[123, 160, 236],
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[181, 172, 131],
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[142, 220, 202],
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[240, 140, 112],
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[172, 145, 164],
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[228, 124, 45],
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[135, 151, 243],
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[42, 205, 125],
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[192, 233, 116],
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[119, 170, 114],
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[158, 138, 26],
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[73, 190, 183],
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[185, 229, 243],
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[227, 107, 55],
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[196, 205, 202],
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[132, 143, 60],
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[233, 192, 237],
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[62, 150, 220],
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[205, 201, 141],
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[106, 140, 190],
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[161, 131, 205],
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[135, 134, 158],
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[198, 139, 81],
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[115, 171, 32],
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[101, 181, 67],
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[149, 137, 119],
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[37, 142, 183],
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[183, 130, 175],
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[168, 125, 133],
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[124, 142, 87],
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[236, 156, 171],
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[232, 194, 91],
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[219, 200, 69],
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[144, 219, 34],
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[219, 95, 187],
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[145, 154, 217],
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[165, 185, 100],
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[127, 238, 163],
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[224, 178, 198],
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[119, 153, 120],
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[124, 212, 92],
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[172, 161, 105],
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[231, 155, 135],
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[157, 132, 101],
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[122, 185, 146],
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[53, 166, 51],
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[70, 163, 90],
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[150, 190, 213],
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[210, 107, 60],
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[166, 152, 185],
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[159, 194, 159],
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[39, 141, 222],
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[202, 176, 161],
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[95, 140, 229],
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[168, 142, 87],
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[93, 170, 203],
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[159, 142, 54],
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[14, 168, 39],
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[94, 150, 149],
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[187, 206, 136],
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[157, 224, 166],
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[235, 158, 208],
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[109, 232, 216],
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[141, 201, 87],
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[208, 124, 118],
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[142, 125, 214],
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[19, 237, 174],
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[72, 219, 41],
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[234, 102, 111],
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[168, 142, 79],
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[188, 135, 35],
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[95, 155, 143],
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[148, 173, 116],
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[223, 112, 95],
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[228, 128, 236],
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[206, 114, 54],
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[195, 119, 88],
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[235, 140, 94],
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[235, 202, 125],
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[233, 155, 153],
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[214, 214, 238],
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[246, 200, 35],
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[151, 125, 171],
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[132, 145, 172],
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[131, 142, 118],
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[199, 126, 150],
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[61, 162, 123],
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[58, 176, 151],
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[215, 141, 69],
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[225, 154, 220],
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[220, 77, 167],
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[233, 161, 64],
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[130, 221, 137],
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[81, 191, 129],
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[169, 162, 140],
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[174, 177, 222],
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[236, 174, 47],
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[233, 188, 180],
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[69, 222, 172],
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[71, 232, 93],
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[118, 211, 238],
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[157, 224, 83],
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[218, 105, 73],
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[126, 169, 36]]
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end
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