discourse/lib/letter_avatar.rb

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