Class: Shipping::PreProcessLabel

Inherits:
BaseService show all
Defined in:
app/services/shipping/pre_process_label.rb

Instance Method Summary collapse

Methods inherited from BaseService

#initialize, #log_debug, #log_error, #log_info, #log_warning, #logger, #options, #tagged_logger

Constructor Details

This class inherits a constructor from BaseService

Instance Method Details

#process(pdf_file_path, out_file_name: nil) ⇒ Object 



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# File 'app/services/shipping/pre_process_label.rb', line 4

def process(pdf_file_path, out_file_name: nil)
  require 'vips'

  pdf_bare_file_name = pdf_file_path.split('/').last.split('.pdf').first
  pdf_directory = pdf_file_path.split(pdf_bare_file_name).first

  # Get number of pages in PDF
  # Load first page to check if multi-page
  first_page = Vips::Image.new_from_file(pdf_file_path, dpi: 144, page: 0, access: :sequential)

  # Try to get page count from PDF loader
  page_count = begin
    Vips::Image.new_from_file(pdf_file_path, dpi: 144, n: -1).get('n-pages')
  rescue StandardError
    1
  end

  combined_pdf = PdfCombinator.new
  files_to_rm = []

  page_count.times do |i|
    img_base_name = "#{pdf_directory}#{pdf_bare_file_name}_tmp_#{i}"
    tmp_png_path = "#{img_base_name}.png"
    tmp_pdf_path = "#{img_base_name}.pdf"

    # Load specific page at 144 DPI
    page_image = Vips::Image.new_from_file(pdf_file_path, dpi: 144, page: i)

    # Flatten alpha with white background
    if page_image.has_alpha?
      page_image = page_image.flatten(background: [255, 255, 255])
    end

    # Process image: resize to 1224x1584, then crop to 672x1008
    page_image = process_image(page_image)

    # Write as 8-bit PNG
    page_image.write_to_file(tmp_png_path, palette: true)
    files_to_rm << tmp_png_path

    # Convert PNG to PDF at 4x6 inches
    # Load the PNG and write as PDF
    png_image = Vips::Image.new_from_file(tmp_png_path)
    png_image.write_to_file(tmp_pdf_path)
    files_to_rm << tmp_pdf_path

    combined_pdf << PdfCombinator.load(tmp_pdf_path)
  end

  out_pdf_file_path = "#{pdf_directory}#{pdf_bare_file_name}_4x6.pdf"
  combined_pdf.save out_pdf_file_path

  # Cleanup temporary files (commented out in original)
  # files_to_rm.each { |tmp_path| FileUtils.rm(tmp_path) }

  out_pdf_file_path
end

#process_image(img) ⇒ Object

Resize to fill 1224x1584, then crop to 672x1008 from center
https://www.imagemagick.org/script/command-line-processing.php#geometry



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# File 'app/services/shipping/pre_process_label.rb', line 64

def process_image(img)
  # Resize to cover 1224x1584 (^ modifier in ImageMagick means "fill")
  scale = [1224.0 / img.width, 1584.0 / img.height].max
  img = img.resize(scale)

  # Crop to 672x1008 from center
  left = [(img.width - 672) / 2, 0].max
  top = [(img.height - 1008) / 2, 0].max
  img.crop(left.to_i, top.to_i, [672, img.width].min, [1008, img.height].min)
end