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@jeffkreeftmeijer
Created April 18, 2011 08:34
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Image difference blend
require 'chunky_png'
include ChunkyPNG::Color
images = [
ChunkyPNG::Image.from_file('1.png'),
ChunkyPNG::Image.from_file('2.png')
]
images.first.height.times do |y|
images.first.row(y).each_with_index do |pixel, x|
images.last[x,y] = rgb(
r(pixel) + r(images.last[x,y]) - 2 * [r(pixel), r(images.last[x,y])].min,
g(pixel) + g(images.last[x,y]) - 2 * [g(pixel), g(images.last[x,y])].min,
b(pixel) + b(images.last[x,y]) - 2 * [b(pixel), b(images.last[x,y])].min
)
end
end
images.last.save('diff.png')
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