Class: HexaPDF::Layout::Style::LinkLayer

Inherits:
Object
  • Object
show all
Defined in:
lib/hexapdf/layout/style.rb

Overview

The LinkLayer class provides support for linking to in-document or remote destinations for Style objects using link annotations. Typical use cases would be linking to a (named) destination on a different page or executing a URI action.

See: PDF1.7 s12.5.6.6, Layers, HexaPDF::Type::Annotations::Link

Instance Method Summary collapse

Constructor Details

#initialize(dest: nil, uri: nil, file: nil, border: false, border_color: nil) ⇒ LinkLayer

Creates a new LinkLayer object.

The following arguments are allowed (note that only one of dest, uri or file may be specified):

dest

The destination array or a name of a named destination for in-document links. If neither dest nor uri nor file is specified, it is assumed that the box has a custom property named ‘link’ which is used for the destination.

uri

The URI to link to.

file

The file that should be opened or, if it refers to an application, the application that should be launched. Can either be a string or a Filespec object. Also see: HexaPDF::Type::FileSpecification.

border

If set to true, a standard border is used. Also accepts an array that adheres to the rules for annotation borders.

border_color

Defines the border color. Can be an array with 0 (transparent), 1 (grayscale), 3 (RGB) or 4 (CMYK) values.

Examples:

LinkLayer.new(dest: [page, :XYZ, nil, nil, nil], border: true)
LinkLayer.new(uri: "https://my.example.com/path", border: [5 5 2])
LinkLayer.new     # use 'link' custom box property for dest



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# File 'lib/hexapdf/layout/style.rb', line 480

def initialize(dest: nil, uri: nil, file: nil, border: false, border_color: nil)
  if dest && (uri || file) || uri && file
    raise ArgumentError, "Only one of dest, uri and file is allowed"
  end
  @dest = dest
  @action = if uri
              {S: :URI, URI: uri}
            elsif file
              {S: :Launch, F: file, NewWindow: true}
            end
  @border = case border
            when false then [0, 0, 0]
            when true then nil
            when Array then border
            else raise ArgumentError, "Invalid value for border: #{border}"
            end
  @border_color = border_color
end

Instance Method Details

#call(canvas, box) ⇒ Object

Creates the needed link annotation if possible, i.e. if the context of the canvas is a page.



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# File 'lib/hexapdf/layout/style.rb', line 501

def call(canvas, box)
  return unless canvas.context.type == :Page
  @dest = box.properties['link'] unless @dest || @action

  page = canvas.context
  matrix = canvas.graphics_state.ctm
  quad_points = [*matrix.evaluate(0, 0), *matrix.evaluate(box.width, 0),
                 *matrix.evaluate(box.width, box.height), *matrix.evaluate(0, box.height)]
  x_minmax = quad_points.values_at(0, 2, 4, 6).minmax
  y_minmax = quad_points.values_at(1, 3, 5, 7).minmax
  annot = {
    Subtype: :Link,
    Rect: [x_minmax[0], y_minmax[0], x_minmax[1], y_minmax[1]],
    QuadPoints: quad_points,
    Dest: @dest,
    A: @action,
    Border: @border,
    C: @border_color && canvas.color_from_specification(@border_color).components,
  }
  (page[:Annots] ||= []) << page.document.add(annot)
end