Class: PDF::Reader::PagesStrategy

Inherits:

Object
AbstractStrategy
PDF::Reader::PagesStrategy

show all

Defined in:: lib/pdf/reader/pages_strategy.rb

Overview

Walks the pages of the PDF file and calls the appropriate callback methods when something of interest is found.

The callback methods should exist on the receiver object passed into the constructor. Whenever some content is found that will trigger a callback, the receiver is checked to see if the callback is defined.

If it is defined it will be called. If not, processing will continue.

Available Callbacks

The following callbacks are available and should be methods defined on your receiver class. Only implement the ones you need - the rest will be ignored.

Some callbacks will include parameters which will be passed in as an array. For callbacks that supply no paramters, or where you don’t need them, the *params argument can be left off. Some example callback method definitions are:

def begin_document
def end_page
def show_text(string, *params)
def fill_stroke(*params)

You should be able to infer the basic command the callback is reporting based on the name. For further experimentation, define the callback with just a *params parameter, then print out the contents of the array using something like:

puts params.inspect

Text Callbacks

All text passed into these callbacks will be encoded as UTF-8. Depending on where (and when) the PDF was generated, there’s a good chance the text is NOT stored as UTF-8 internally so be careful when doing a comparison on strings returned from PDF::Reader (when doing unit tests for example). The string may not be byte-by-byte identical with the string that was originally written to the PDF.

end_text_object
move_to_start_of_next_line
set_character_spacing
move_text_position
move_text_position_and_set_leading
set_text_font_and_size
show_text
show_text_with_positioning
set_text_leading
set_text_matrix_and_text_line_matrix
set_text_rendering_mode
set_text_rise
set_word_spacing
set_horizontal_text_scaling
move_to_next_line_and_show_text
set_spacing_next_line_show_text

If the :raw_text option was passed to the PDF::Reader class the following callbacks may also appear:

show_text_raw
show_text_with_positioning_raw
move_to_next_line_and_show_text_raw
set_spacing_next_line_show_text_raw

Graphics Callbacks

close_fill_stroke
fill_stroke
close_fill_stroke_with_even_odd
fill_stroke_with_even_odd
begin_marked_content_with_pl
begin_inline_image
begin_marked_content
begin_text_object
append_curved_segment
concatenate_matrix
set_stroke_color_space
set_nonstroke_color_space
set_line_dash
set_glyph_width
set_glyph_width_and_bounding_box
invoke_xobject
define_marked_content_with_pl
end_inline_image
end_marked_content
fill_path_with_nonzero
fill_path_with_nonzero
fill_path_with_even_odd
set_gray_for_stroking
set_gray_for_nonstroking
set_graphics_state_parameters
close_subpath
set_flatness_tolerance
begin_inline_image_data
set_line_join_style
set_line_cap_style
set_cmyk_color_for_stroking,
set_cmyk_color_for_nonstroking
append_line
begin_new_subpath
set_miter_limit
define_marked_content_point
end_path
save_graphics_state
restore_graphics_state
append_rectangle
set_rgb_color_for_stroking
set_rgb_color_for_nonstroking
set_color_rendering_intent
close_and_stroke_path
stroke_path
set_color_for_stroking
set_color_for_nonstroking
set_color_for_stroking_and_special
set_color_for_nonstroking_and_special
paint_area_with_shading_pattern
append_curved_segment_initial_point_replicated
set_line_width
set_clipping_path_with_nonzero
set_clipping_path_with_even_odd
append_curved_segment_final_point_replicated

Misc Callbacks

begin_compatibility_section
end_compatibility_section,
begin_document
end_document
begin_page_container
end_page_container
begin_page
end_page
metadata
xml_metadata
page_count
begin_form_xobject
end_form_xobject

Resource Callbacks

Each page can contain (or inherit) a range of resources required for the page, including things like fonts and images. The following callbacks may appear after begin_page if the relevant resources exist on a page:

resource_procset
resource_xobject
resource_extgstate
resource_colorspace
resource_pattern
resource_font

In most cases, these callbacks associate a name with each resource, allowing it to be referred to by name in the page content. For example, an XObject can hold an image. If it gets mapped to the name “IM1”, then it can be placed on the page using invoke_xobject “IM1”.

DEPRECATED: this class was deprecated in version 0.11.0 and will

eventually be removed

Constant Summary collapse

OPERATORS = :nodoc:

{
  'b'   => :close_fill_stroke,
  'B'   => :fill_stroke,
  'b*'  => :close_fill_stroke_with_even_odd,
  'B*'  => :fill_stroke_with_even_odd,
  'BDC' => :begin_marked_content_with_pl,
  'BI'  => :begin_inline_image,
  'BMC' => :begin_marked_content,
  'BT'  => :begin_text_object,
  'BX'  => :begin_compatibility_section,
  'c'   => :append_curved_segment,
  'cm'  => :concatenate_matrix,
  'CS'  => :set_stroke_color_space,
  'cs'  => :set_nonstroke_color_space,
  'd'   => :set_line_dash,
  'd0'  => :set_glyph_width,
  'd1'  => :set_glyph_width_and_bounding_box,
  'Do'  => :invoke_xobject,
  'DP'  => :define_marked_content_with_pl,
  'EI'  => :end_inline_image,
  'EMC' => :end_marked_content,
  'ET'  => :end_text_object,
  'EX'  => :end_compatibility_section,
  'f'   => :fill_path_with_nonzero,
  'F'   => :fill_path_with_nonzero,
  'f*'  => :fill_path_with_even_odd,
  'G'   => :set_gray_for_stroking,
  'g'   => :set_gray_for_nonstroking,
  'gs'  => :set_graphics_state_parameters,
  'h'   => :close_subpath,
  'i'   => :set_flatness_tolerance,
  'ID'  => :begin_inline_image_data,
  'j'   => :set_line_join_style,
  'J'   => :set_line_cap_style,
  'K'   => :set_cmyk_color_for_stroking,
  'k'   => :set_cmyk_color_for_nonstroking,
  'l'   => :append_line,
  'm'   => :begin_new_subpath,
  'M'   => :set_miter_limit,
  'MP'  => :define_marked_content_point,
  'n'   => :end_path,
  'q'   => :save_graphics_state,
  'Q'   => :restore_graphics_state,
  're'  => :append_rectangle,
  'RG'  => :set_rgb_color_for_stroking,
  'rg'  => :set_rgb_color_for_nonstroking,
  'ri'  => :set_color_rendering_intent,
  's'   => :close_and_stroke_path,
  'S'   => :stroke_path,
  'SC'  => :set_color_for_stroking,
  'sc'  => :set_color_for_nonstroking,
  'SCN' => :set_color_for_stroking_and_special,
  'scn' => :set_color_for_nonstroking_and_special,
  'sh'  => :paint_area_with_shading_pattern,
  'T*'  => :move_to_start_of_next_line,
  'Tc'  => :set_character_spacing,
  'Td'  => :move_text_position,
  'TD'  => :move_text_position_and_set_leading,
  'Tf'  => :set_text_font_and_size,
  'Tj'  => :show_text,
  'TJ'  => :show_text_with_positioning,
  'TL'  => :set_text_leading,
  'Tm'  => :set_text_matrix_and_text_line_matrix,
  'Tr'  => :set_text_rendering_mode,
  'Ts'  => :set_text_rise,
  'Tw'  => :set_word_spacing,
  'Tz'  => :set_horizontal_text_scaling,
  'v'   => :append_curved_segment_initial_point_replicated,
  'w'   => :set_line_width,
  'W'   => :set_clipping_path_with_nonzero,
  'W*'  => :set_clipping_path_with_even_odd,
  'y'   => :append_curved_segment_final_point_replicated,
  '\''  => :move_to_next_line_and_show_text,
  '"'   => :set_spacing_next_line_show_text,
}

Class Method Summary collapse

.to_sym ⇒ Object

Instance Method Summary collapse

#process ⇒ Object

Begin processing the document.

Methods inherited from AbstractStrategy

#initialize

Constructor Details

This class inherits a constructor from PDF::Reader::AbstractStrategy

Class Method Details

.to_sym ⇒ `Object`



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# File 'lib/pdf/reader/pages_strategy.rb', line 256

def self.to_sym
  :pages
end

Instance Method Details

#process ⇒ `Object`

Begin processing the document

# File 'lib/pdf/reader/pages_strategy.rb', line 261

def process
  return false unless options[:pages]

  callback(:begin_document, [root])
  walk_pages(@ohash.object(root[:Pages]))
  callback(:end_document)
end