PDF大虾：图像覆盖文本的问题

Question

我想在每个页面上放置一个图像作为背景。这是我的代码：

Prawn::Document.generate("#{Rails.root.to_s}/public/#{filename}.pdf", :page_size => [576,576], :left_margin => 50,:right_margin => 50, :page_layout => :portrait, :skip_page_creation => true, :skip_encoding => true ) do |pdf|

  pdf.repeat :all do
    pdf.image open(APP_CONFIG['site_url']+"/images/pdf/bg_blank_high.jpg"), :at => [-pdf.bounds.absolute_left,  pdf.bounds.absolute_top], :width => 576, :height => 576
  end

  pdf.start_new_page(:margin => [75,50,50,50]) 
  pdf.fill_color "8c8464"
  pdf.text story.contents, :size => 12, :align => :left, :leading => 3 
end 

问题是 - 图像覆盖所有页面中的文本。

有没有办法将文本放在图像上或使图像“发送到后面”或任何其他想法？

Answer 1

看起来重复块中的代码是在文本渲染后调用的，因此将其放在文本的“上方”。
提供的代码片段有效，因为它只涉及单个图像。

prawn_document( filename:       "filename.pdf",
                background:     path_background_image) do |pdf|
...

可能对你有用。但它只提供低分辨率（72 dpi）图像。

有一个允许设置背景图像分辨率的拉取请求：
https://github.com/sandal/prawn/pull/292

Answer 2

在 Prawn 手册中，他们给出了一个被文本覆盖的图像的示例：

# images/absolute_position.rb
# One of the options that the image method accepts is :at. If you've read some of the graphics
# examples you are probably already familiar with it. Just provide it the upper-left corner where you
# want the image placed.
# While sometimes useful this option won't be practical. Notice that the cursor won't be moved after the
# image is rendered and there is nothing forbidding the text to overlap with the image.

y_position = cursor
text "The image won't go below this line of text."
image "#{Prawn::BASEDIR}/data/images/fractal.jpg", :at => [200, y_position]
text "And this line of text will go just below the previous one."

因此，据我所知，这可能是您构建文档的方式或光标放置的问题。