Class: PDF::Margins::Checker

Inherits:
Object
  • Object
show all
Defined in:
lib/pdf/margins/checker.rb

Constant Summary collapse

MM_TO_PTS = 
2.83464567
DEFAULT_RESOLUTION = 
72
SCALE_MULTIPLIER =

If we find that we need higher resolution for better precision then we can adjust the SCALE_MULTIPLIER at the cost of speed.

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RESOLUTION = 
DEFAULT_RESOLUTION * SCALE_MULTIPLIER

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(file_path, top_margin, right_margin, bottom_margin, left_margin, spreads = false) ⇒ Checker

Dimensions are in mm, to be converted to PDF points later. Pass spreads as true to check left and right margins of spreads, not pages.



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# File 'lib/pdf/margins/checker.rb', line 22

def initialize(file_path, top_margin, right_margin, bottom_margin, left_margin, spreads=false)
  @file_path     = file_path
  @top_margin    = top_margin
  @right_margin  = right_margin
  @bottom_margin = bottom_margin
  @left_margin   = left_margin
  @spreads       = spreads
end

Instance Attribute Details

#bottom_margin ⇒ Object (readonly)

Returns the value of attribute bottom_margin.



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# File 'lib/pdf/margins/checker.rb', line 18

def bottom_margin
  @bottom_margin
end

#file_path ⇒ Object (readonly)

Returns the value of attribute file_path.



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# File 'lib/pdf/margins/checker.rb', line 18

def file_path
  @file_path
end

#left_margin ⇒ Object (readonly)

Returns the value of attribute left_margin.



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# File 'lib/pdf/margins/checker.rb', line 18

def left_margin
  @left_margin
end

#right_margin ⇒ Object (readonly)

Returns the value of attribute right_margin.



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# File 'lib/pdf/margins/checker.rb', line 18

def right_margin
  @right_margin
end

#spreads ⇒ Object (readonly)

Returns the value of attribute spreads.



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# File 'lib/pdf/margins/checker.rb', line 18

def spreads
  @spreads
end

#top_margin ⇒ Object (readonly)

Returns the value of attribute top_margin.



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# File 'lib/pdf/margins/checker.rb', line 18

def top_margin
  @top_margin
end

Instance Method Details

#issues ⇒ Object 



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# File 'lib/pdf/margins/checker.rb', line 31

def issues
  temp_dir_path = Dir.mktmpdir("pdf_margins")

  begin
    # This produces greyscale PNGs - we throw the colour away because we
    # don't need it to check for margins.
    system("mudraw -g -b 0 -r #{RESOLUTION} -o #{temp_dir_path}/%d.png #{file_path}") || raise(PDF::Margins::MuDrawCommandError)

    issues = []

    files = Dir.glob("#{temp_dir_path}/*.png")
    # ensure the files are sorted naturally
    files = files.sort_by{ |f| f.split('/').last.to_i }

    files.each_with_index do |png_path, index|
      image = ChunkyPNG::Image.from_file(png_path)
      page_number = index + 1

      if dirty_top_margin?(image, top_margin)
        issues << Issue.new(page_number, :top)
      end

      if dirty_bottom_margin?(image, bottom_margin)
        issues << Issue.new(page_number, :bottom)
      end

      if (!spreads || page_number % 2 == 0) && dirty_left_margin?(image, left_margin)
        issues << Issue.new(page_number, :left)
      end
      
      if (!spreads || page_number % 2 != 0) && dirty_right_margin?(image, right_margin)
        issues << Issue.new(page_number, :right)
      end
    end

  ensure
    FileUtils.remove_entry(temp_dir_path)
  end

  return issues
end