demarches-normaliennes/app/jobs/titre_identite_watermark_job.rb
2020-11-25 16:19:06 +01:00

70 lines
1.7 KiB
Ruby

class TitreIdentiteWatermarkJob < ApplicationJob
queue_as :active_storage_watermark
MAX_IMAGE_SIZE = 1500
SCALE = 0.9
WATERMARK = Rails.root.join("app/assets/images/#{WATERMARK_FILE}")
def perform(blob)
blob.open do |file|
watermark = resize_watermark(file)
processed = watermark_image(file, watermark)
blob.metadata[:watermark] = true
blob.upload(processed)
blob.save
end
end
private
def watermark_image(file, watermark)
ImageProcessing::MiniMagick
.source(file)
.convert("png")
.resize_to_limit(MAX_IMAGE_SIZE, MAX_IMAGE_SIZE)
.composite(watermark, mode: "over", gravity: "center")
.call
end
def resize_watermark(file)
metadata = image_metadata(file)
width = [metadata[:width], MAX_IMAGE_SIZE].min * SCALE
height = [metadata[:height], MAX_IMAGE_SIZE].min * SCALE
diagonal = Math.sqrt(height**2 + width**2)
angle = Math.asin(height / diagonal) * 180 / Math::PI
ImageProcessing::MiniMagick
.source(WATERMARK)
.resize_to_limit(diagonal, diagonal / 2)
.rotate(-angle, background: :transparent)
.call
end
def image_metadata(file)
read_image(file) do |image|
if rotated_image?(image)
{ width: image.height, height: image.width }
else
{ width: image.width, height: image.height }
end
end
end
def read_image(file)
require "mini_magick"
image = MiniMagick::Image.new(file.path)
if image.valid?
yield image
else
logger.info "Skipping image analysis because ImageMagick doesn't support the file"
{}
end
end
def rotated_image?(image)
['RightTop', 'LeftBottom'].include?(image["%[orientation]"])
end
end