57 lines
1.6 KiB
Ruby
57 lines
1.6 KiB
Ruby
# frozen_string_literal: true
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module Tooling
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module Image
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# Determine the tolerance till when we run pngquant in a loop
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TOLERANCE = 10000
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def self.check_executables
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unless system('pngquant --version', out: File::NULL)
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warn(
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'Error: pngquant executable was not detected in the system.',
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'Download pngquant at https://pngquant.org/ and place the executable in /usr/local/bin'
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)
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abort
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end
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unless system('gm version', out: File::NULL)
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warn(
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'Error: gm executable was not detected in the system.',
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'Please install imagemagick: brew install imagemagick or sudo apt install imagemagick'
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)
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abort
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end
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end
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def self.compress_image(file, keep_original = false)
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check_executables
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compressed_file = "#{file}.compressed"
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FileUtils.copy(file, compressed_file)
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pngquant_file = PngQuantizator::Image.new(compressed_file)
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# Run the image repeatedly through pngquant until
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# the change in file size is within TOLERANCE
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# or the loop count is above 1000
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1000.times do
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before = File.size(compressed_file)
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pngquant_file.quantize!
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after = File.size(compressed_file)
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break if before - after <= TOLERANCE
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end
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savings = File.size(file) - File.size(compressed_file)
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is_uncompressed = savings > TOLERANCE
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if is_uncompressed && !keep_original
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FileUtils.copy(compressed_file, file)
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end
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FileUtils.remove(compressed_file)
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[is_uncompressed, savings]
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end
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end
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end
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