Builds an info object (Prawn::Images::*) and a PDF reference representing the given image. Return a pair: [pdf_obj, info].
@private
# File lib/prawn/images.rb, line 77 def build_image_object(file) io = verify_and_open_image(file) image_content = io.read 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 min_version(info.min_pdf_version) if info.respond_to?(:min_pdf_version) # 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 pdf_obj that has been added to the page’s resources and an info object (the pair returned from build_image_object), embed the image according to the options given.
@private
# File lib/prawn/images.rb, line 107 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.merge!(label => pdf_obj) # add the image to the current page instruct = "\nq\n%.3f 0 0 %.3f %.3f %.3f cm\n/%s Do\nQ" add_content instruct % [ w, h, x, y - h, label ] end
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:
file |
path to file or an object that responds to read and rewind |
Options:
:at |
an array [x,y] with the location of the top left corner of the image. |
:position |
One of (:left, :center, :right) or an x-offset |
:vposition |
One of (:top, :center, :center) or an y-offset |
:height |
the height of the image [actual height of the image] |
:width |
the width of the image [actual width of the image] |
:scale |
scale the dimensions of the image proportionally |
:fit |
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://prawn.majesticseacreature.com/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)
# File lib/prawn/images.rb, line 62 def image(file, options={}) Prawn.verify_options [:at, :position, :vposition, :height, :width, :scale, :fit], options pdf_obj, info = build_image_object(file) embed_image(pdf_obj, info, options) info end
Generated with the Darkfish Rdoc Generator 2.