Question

我正在开发一个从Ruby on Rails 4中的Express Carriers获取货运标签的应用程序。此刻，我正在使用UPS API及其标签（即GIF图像）。为了能够生成包含GIF标签的PDF，我使用了不支持GIF的Prawn。因此，GIF转换为PNG。我可以贴标签，但是当我打印出来时，质量很低，而且很难看清标签内的内容。我需要了解如何添加更好的质量，否则标签将无法使用。

我正在上的课：

class UPSLabelConsolidation
  attr_reader :base64_encoded_gif_labels

  def initialize(base64_encoded_gif_labels)
    @base64_encoded_gif_labels = base64_encoded_gif_labels
  end

  def perform!
    identifier = SecureRandom.hex(3)

    tmp_label_files = base64_encoded_gif_labels.each_with_index.map do |base64_encoded_gif_label, index|
      tmp_label_file = Tempfile.new(["ups-label-#{identifier}-#{index}", ".png"], Rails.root.join("tmp"))
      tmp_label_file.binmode

      image = MiniMagick::Image.read(Base64.decode64(base64_encoded_gif_label), "gif")

      image.combine_options do |b|
        b.rotate "90" # Rotate 90-degrees clockwise
        b.crop "800x1000+0+0" # Crop ~200px whitespace from the bottom of the label
      end

      image.format("png") # Prawn does not support GIF, so we convert it here.
      image.write(tmp_label_file.path)

      tmp_label_file.rewind

      tmp_label_file
    end

    new_page = false
    @pdf = Prawn::Document.new(page_size: [297, 390], margin: 20, page_layout: :portrait) # Margin is ~0.7cm

    tmp_label_files.each do |label_file|
      @pdf.start_new_page if new_page
      @pdf.image label_file, width: 250, position: :left # Width is ~8.8cm
      new_page = true
    end
  end

  def write!(path)
    if @pdf
      @pdf.render_file(path)
    else
      raise "`#perform!` before `#write!`"
    end
  end
end

如何使用Gemini MiniMagik管理图像质量

0 个答案: