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# encoding: ASCII-8BIT
# frozen_string_literal: true
# images.rb : Implements PDF image embedding
#
# Copyright April 2008, James Healy, Gregory Brown. All Rights Reserved.
#
# This is free software. Please see the LICENSE and COPYING files for details.
require 'digest/sha1'
require 'pathname'
module Prawn
module Images
# @group Stable API
# Add the image at filename to the current page. Currently only
# JPG and PNG files are supported. (Note that processing PNG
# images with alpha channels can be processor and memory intensive.)
#
# Arguments:
# <tt>file</tt>:: path to file or an object that responds to #read and
# #rewind
#
# Options:
# <tt>:at</tt>:: an array [x,y] with the location of the top left corner of
# the image.
# <tt>:position</tt>:: One of (:left, :center, :right) or an x-offset
# <tt>:vposition</tt>:: One of (:top, :center, :bottom) or an y-offset
# <tt>:height</tt>:: the height of the image [actual height of the image]
# <tt>:width</tt>:: the width of the image [actual width of the image]
# <tt>:scale</tt>:: scale the dimensions of the image proportionally
# <tt>:fit</tt>:: scale the dimensions of the image proportionally to fit
# inside [width,height]
#
# Prawn::Document.generate("image2.pdf", :page_layout => :landscape) do
# pigs = "#{Prawn::DATADIR}/images/pigs.jpg"
# image pigs, :at => [50,450], :width => 450
#
# dice = "#{Prawn::DATADIR}/images/dice.png"
# image dice, :at => [50, 450], :scale => 0.75
# end
#
# If only one of :width / :height are provided, the image will be scaled
# proportionally. When both are provided, the image will be stretched to
# fit the dimensions without maintaining the aspect ratio.
#
#
# If :at is provided, the image will be place in the current page but
# the text position will not be changed.
#
#
# If instead of an explicit filename, an object with a read method is
# passed as +file+, you can embed images from IO objects and things
# that act like them (including Tempfiles and open-uri objects).
#
# require "open-uri"
#
# Prawn::Document.generate("remote_images.pdf") do
# image open("http://prawnpdf.org/media/prawn_logo.png")
# end
#
# This method returns an image info object which can be used to check the
# dimensions of an image object if needed.
# (See also: Prawn::Images::PNG , Prawn::Images::JPG)
#
def image(file, options = {})
Prawn.verify_options %i[
at position vposition height
width scale fit
], options
pdf_obj, info = build_image_object(file)
embed_image(pdf_obj, info, options)
info
end
# Builds an info object (Prawn::Images::*) and a PDF reference representing
# the given image. Return a pair: [pdf_obj, info].
#
# @private
def build_image_object(file)
image_content = verify_and_read_image(file)
image_sha1 = Digest::SHA1.hexdigest(image_content)
# if this image has already been embedded, just reuse it
if image_registry[image_sha1]
info = image_registry[image_sha1][:info]
image_obj = image_registry[image_sha1][:obj]
else
# Build the image object
info = Prawn.image_handler.find(image_content).new(image_content)
# Bump PDF version if the image requires it
if info.respond_to?(:min_pdf_version)
renderer.min_version(info.min_pdf_version)
end
# Add the image to the PDF and register it in case we see it again.
image_obj = info.build_pdf_object(self)
image_registry[image_sha1] = { obj: image_obj, info: info }
end
[image_obj, info]
end
# Given a PDF image resource <tt>pdf_obj</tt> that has been added to the
# page's resources and an <tt>info</tt> object (the pair returned from
# build_image_object), embed the image according to the <tt>options</tt>
# given.
#
# @private
def embed_image(pdf_obj, info, options)
# find where the image will be placed and how big it will be
w, h = info.calc_image_dimensions(options)
if options[:at]
x, y = map_to_absolute(options[:at])
else
x, y = image_position(w, h, options)
move_text_position h
end
# add a reference to the image object to the current page
# resource list and give it a label
label = "I#{next_image_id}"
state.page.xobjects[label] = pdf_obj
cm_params = PDF::Core.real_params([w, 0, 0, h, x, y - h])
renderer.add_content("\nq\n#{cm_params} cm\n/#{label} Do\nQ")
end
private
def verify_and_read_image(io_or_path)
# File or IO
if io_or_path.respond_to?(:rewind)
io = io_or_path
# Rewind if the object we're passed is an IO, so that multiple embeds of
# the same IO object will work
io.rewind
# read the file as binary so the size is calculated correctly
# guard binmode because some objects acting io-like don't implement it
io.binmode if io.respond_to?(:binmode)
return io.read
end
# String or Pathname
io_or_path = Pathname.new(io_or_path)
raise ArgumentError, "#{io_or_path} not found" unless io_or_path.file?
io_or_path.binread
end
def image_position(width, height, options)
options[:position] ||= :left
y = case options[:vposition]
when :top
bounds.absolute_top
when :center
bounds.absolute_top - (bounds.height - height) / 2.0
when :bottom
bounds.absolute_bottom + height
when Numeric
bounds.absolute_top - options[:vposition]
else
determine_y_with_page_flow(height)
end
x = case options[:position]
when :left
bounds.left_side
when :center
bounds.left_side + (bounds.width - width) / 2.0
when :right
bounds.right_side - width
when Numeric
options[:position] + bounds.left_side
end
[x, y]
end
def determine_y_with_page_flow(height)
if overruns_page?(height)
bounds.move_past_bottom
end
y
end
def overruns_page?(height)
(y - height) < reference_bounds.absolute_bottom
end
def image_registry
@image_registry ||= {}
end
def next_image_id
@image_counter ||= 0
@image_counter += 1
end
end
end
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