Class: Preflight::Rules::MinBleed

Inherits:
Object
  • Object
show all
Extended by:
Forwardable
Includes:
Measurements
Defined in:
lib/preflight/rules/min_bleed.rb

Overview

To print colour to the edge of the page you must print past the intended page edge and then trim the printed sheet. The printed area that will be trimmed is called bleed. Generally you will probably want 3-4mm of bleed.

Arguments: the distance from the TrimBox within which objects MUST include bleed

the distance past the TrimBox that objects MUST bleed
the units (:pt, :mm, :in)

Usage:

class MyPreflight
  include Preflight::Profile

  rule Preflight::Rules::MinBleed, 1, 4, :mm
  rule Preflight::Rules::MinBleed, 12, 50, :pt
  rule Preflight::Rules::MinBleed, 0.1, 0.25, :in
end

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(range, bleed, units) ⇒ MinBleed

Returns a new instance of MinBleed.



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# File 'lib/preflight/rules/min_bleed.rb', line 39

def initialize(range, bleed, units)
  @range, @bleed, @units = range, bleed, units
end

Instance Attribute Details

#issues ⇒ Object (readonly)

Returns the value of attribute issues.



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# File 'lib/preflight/rules/min_bleed.rb', line 31

def issues
  @issues
end

Instance Method Details

#append_rectangle(x1, y1, x2, y2) ⇒ Object 



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# File 'lib/preflight/rules/min_bleed.rb', line 79

def append_rectangle(x1, y1, x2, y2)
  @path ||= []
  @path << @state.ctm_transform(x1, y1)
  @path << @state.ctm_transform(x1, y2)
  @path << @state.ctm_transform(x2, y1)
  @path << @state.ctm_transform(x2, y2)
end

#close_and_stroke_path ⇒ Object 



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# File 'lib/preflight/rules/min_bleed.rb', line 102

def close_and_stroke_path
  @path = []
end

#end_path ⇒ Object 



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# File 'lib/preflight/rules/min_bleed.rb', line 110

def end_path
  @path = []
end

#fill_path_with_nonzero ⇒ Object Also known as: fill_path_with_even_odd 



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# File 'lib/preflight/rules/min_bleed.rb', line 87

def fill_path_with_nonzero
  @path ||= []
  points = select_points_in_danger_zone(@path)

  if points.size > 0
    @issues << Issue.new("Filled object with insufficient bleed", self, :page        => @page.number,
                                                                        :object_type => :filled_object,
                                                                        :bleed       => @bleed,
                                                                        :units       => @units)
  end

  @path = []
end

#invoke_xobject(label) ⇒ Object

As each image is drawn on the canvas, determine the amount of device space it’s being crammed into and therefore the PPI.



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# File 'lib/preflight/rules/min_bleed.rb', line 66

def invoke_xobject(label)
  @state.invoke_xobject(label) do |xobj|
    case xobj
    when PDF::Reader::FormXObject then
      xobj.walk(self)
    when PDF::Reader::Stream
      invoke_image_xobject(xobj) if xobj.hash[:Subtype] == :Image
    else
      raise xobj.inspect
    end
  end
end

#page=(page) ⇒ Object

we’re about to start a new page, reset state



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# File 'lib/preflight/rules/min_bleed.rb', line 45

def page=(page)
  @issues  = []
  @page    = page
  @state   = PDF::Reader::PageState.new(page)
  @objects = page.objects

  attrs = @page.attributes
  box   = attrs[:TrimBox] || attrs[:ArtBox] || attrs[:MediaBox]
  @warning_min_x = box[0] + to_points(@range, @units)
  @warning_min_y = box[1] + to_points(@range, @units)
  @warning_max_x = box[2] - to_points(@range, @units)
  @warning_max_y = box[3] - to_points(@range, @units)
  @error_min_x   = box[0] - to_points(@bleed, @units)
  @error_min_y   = box[1] - to_points(@bleed, @units)
  @error_max_x   = box[2] + to_points(@bleed, @units)
  @error_max_y   = box[3] + to_points(@bleed, @units)
end

#stroke_path ⇒ Object 



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# File 'lib/preflight/rules/min_bleed.rb', line 106

def stroke_path
  @path = []
end