HomeExamplesDocsCodeNews
Home  »  Docs  »  API Reference  »  HexaPDF  »  HexaPDF::Composer

Classes and Modules

class HexaPDF::Composer

Parent Object

The composer class can be used to create PDF documents from scratch. It uses HexaPDF::Layout::Frame and HexaPDF::Layout::Box objects underneath and binds them together to provide a convenient interface for working with them.

Usage ↑

First, a new Composer objects needs to be created, either using ::new or the utility method ::create.

On creation a HexaPDF::Document object is created as well the first page and an accompanying HexaPDF::Layout::Frame object. The frame is used by the various methods for general document layout tasks, like positioning of text, images, and so on. By default, it covers the whole page except the margin area. How the frame gets created can be customized by defining a custom page style, see page_style. Use the skip_page_creation argument to avoid the initial page creation when creating a Composer instance.

Once the Composer object is created, its methods can be used to draw text, images, … on the page. Behind the scenes HexaPDF::Layout::Box (and subclass) objects are created using the HexaPDF::Document::Layout methods and drawn on the page via the frame.

If the frame of a page is full and a box doesn’t fit anymore, a new page is automatically created. The box is either split into two boxes where one fits on the first page and the other on the new page, or it is drawn completely on the new page. A new page can also be created by calling the new_page method, optionally providing a page style.

The x and y methods provide the point where the next box would be drawn if it fits the available space. This information can be used, for example, for custom drawing operations through canvas which provides direct access to the HexaPDF::Content::Canvas object of the current page.

When using canvas and modifying the graphics state, care has to be taken to avoid problems with later box drawing operations since the graphics state cannot completely be reset (e.g. transformations of the canvas cannot always be undone). So it is best to save the graphics state before and restore it afterwards.

Example ↑

HexaPDF::Composer.create('out.pdf', page_size: :A6, margin: 36) do |pdf|
  pdf.style(:base, font_size: 20, text_align: :center)
  pdf.text("Hello World", text_valign: :center)
end

See: HexaPDF::Document::Layout, HexaPDF::Layout::Frame, HexaPDF::Layout::Box

Attributes

canvas[R]

The canvas instance (a Content::Canvas object) of the current page.

Can be used to perform arbitrary drawing operations.

document[R]

The PDF document (HexaPDF::Document) that is created.

frame[R]

The HexaPDF::Layout::Frame for automatic box placement.

page[R]

The current page (a HexaPDF::Type::Page object).

Public Class Methods

create(output, **options, &block)

Creates a new PDF document and writes it to output. The argument options and block are passed to ::new.

Example:

HexaPDF::Composer.create('out.pdf', margin: 36) do |pdf|
  ...
end
new(skip_page_creation: false, page_size: :A4, page_orientation: :portrait, margin: 36) { |composer| ... }

Creates a new Composer object and optionally yields it to the given block.

skip_page_creation

If this argument is false (the default), the arguments page_size, page_orientation and margin are used to create a page style with the name :default. Additionally, an initial page/frame is created using this page style.

Otherwise, i.e. when this argument is true, no initial page or default page style is created. This is useful when the first page needs a custom page style. The page_style method needs to be used to define a page style which is then used with the new_page method to create the initial page/frame.

page_size

Can be any valid predefined page size (see Type::Page::PAPER_SIZE) or an array [llx, lly, urx, ury] specifying a custom page size.

Only used if skip_page_creation is false.

page_orientation

Specifies the orientation of the page, either :portrait or :landscape, if page_size is one of the predefined page sizes.

Only used if skip_page_creation is false.

margin

The margin to use. See HexaPDF::Layout::Style::Quad#set for possible values.

Only used if skip_page_creation is false.

Example:

# Uses the default values
composer = HexaPDF::Composer.new

HexaPDF::Composer.new(page_size: :Letter, margin: 72) do |composer|
  #...
end

HexaPDF::Composer.new(skip_page_creation: true) do |composer|
  composer.page_style(:default) do |canvas, style|
    style.frame = style.create_frame(canvas.context, 36)
  end
  composer.new_page
  # ...
end

Public Instance Methods

box(name, width: 0, height: 0, style: nil, **box_options, &block)

Draws the named box at the current position (see x and y).

It uses HexaPDF::Document::Layout#box behind the scenes to create the named box. See that method for details on the arguments.

Examples:

composer.box(:image, image: composer.document.images.add(machu_picchu))

See: HexaPDF::Document::Layout#box

create_stamp(width, height) { |canvas| ... }

Creates a stamp (Form XObject) which can be used like an image multiple times on a single page or on multiple pages.

The width and the height of the stamp need to be set (frame.width/height or page.box.width/height might be good choices).

Examples:

stamp = composer.create_stamp(50, 50) do |canvas|
  canvas.fill_color("hp-blue").line_width(5).
    rectangle(10, 10, 30, 30).fill_stroke
end
composer.image(stamp, width: 20, height: 20)
composer.image(stamp, width: 50)

draw_box(box)

Draws the given HexaPDF::Layout::Box and returns the last drawn box.

The box is drawn into the current frame if possible. If it doesn’t fit, the box is split. If it still doesn’t fit, a new region of the frame is determined and then the process starts again.

If none or only some parts of the box fit into the current frame, one or more new pages are created for the rest of the box.

formatted_text(data, width: 0, height: 0, style: nil, box_style: nil, **style_properties)

Draws text like text but allows parts of the text to be formatted differently and interspersing with inline boxes.

It uses HexaPDF::Document::Layout#formatted_text_box behind the scenes to create the HexaPDF::Layout::TextBox that does the actual work. See that method for details on the arguments.

Examples:

composer.formatted_text(["Some string"])
composer.formatted_text(["Some ", {text: "string", fill_color: "hp-orange"}])
composer.formatted_text(["Some ", {link: "https://example.com",
                                   fill_color: 'hp-blue', text: "Example"}])
composer.formatted_text(["Some ", {text: "string", style: {font_size: 20}}])
block = lambda {|list| list.text("First item"); list.text("Second item") }
composer.formatted_text(["Some ", {box: :list, width: 50,
                                   valign: :bottom, block: block}])

See: text, HexaPDF::Layout::TextBox, HexaPDF::Layout::TextFragment

image(file, width: 0, height: 0, style: nil, **style_properties)

Draws the given image at the current position (see x and y).

It uses HexaPDF::Document::Layout#image_box behind the scenes to create the HexaPDF::Layout::ImageBox that does the actual work. See that method for details on the arguments.

Examples:

composer.image(machu_picchu, border: {width: 3})
composer.image(machu_picchu, height: 30)

See: HexaPDF::Layout::ImageBox

method_missing(name, *args, **kwargs, &block)

Draws any custom box that can be created using HexaPDF::Document::Layout.

This includes all named boxes defined in the ‘layout.boxes.map’ configuration option.

Examples:

composer.lorem_ipsum(sentences: 1, margin: [0, 0, 5])
composer.list(item_spacing: 2) do |list|
  composer.document.config['layout.boxes.map'].each do |name, klass|
    list.formatted_text([{text: name.to_s, fill_color: "hp-blue-dark"}, "\n#{klass}"],
                        font_size: 8)
  end
end

See: HexaPDF::Document::Layout#box

Calls superclass method
new_page(style = @next_page_style)

Creates a new page, making it the current one.

The page style (see page_style) to use for the new page can be set via the style argument. If not provided, the currently set page style is used (:default is the initial value for @next_page_style).

The applied page style determines the page style that should be used for the following new pages (see Layout::PageStyle#next_style). If this information is not provided by the applied page style, that page style is used again.

Examples:

# Define two page styles
composer.page_style(:cover, page_size: :A4, next_style: :content)
composer.page_style(:content, page_size: :A4)

composer.new_page(:cover)           # uses the :cover style, set next style to :content
composer.new_page                   # uses the :content style, next style again :content
page_style(name) → page_style
page_style(name, **attributes, &template_block) → page_style

Creates and/or returns the page style name.

If no attributes are given, the page style name is returned. In case it does not exist, nil is returned.

If one or more page style attributes are given, a new HexaPDF::Layout::PageStyle object with those attribute values is created, stored under name and returned. Additionally, if a block is provided, it is used to define the page template.

Example:

composer.page_style(:default)
composer.page_style(:cover, page_size: :A4) do |canvas, style|
  page_box = canvas.context.box
  canvas.fill_color("green") do
    canvas.rectangle(0, 0, page_box.width, page_box.height).
      fill
  end
  style.frame = style.create_frame(canvas.context, 36)
end

See: HexaPDF::Layout::PageStyle

style(name) → style
style(name, base: :base, **properties) → style

Creates or updates the HexaPDF::Layout::Style object called name with the given property values and returns it.

If neither base nor any style properties are specified, the style name is just returned.

See HexaPDF::Document::Layout#style for details; this method is just a thin wrapper around that method.

Example:

composer.style(:base, font_size: 12, leading: 1.2)
composer.style(:header, font: 'Helvetica', fill_color: "008")
composer.style(:header1, base: :header, font_size: 30)

See: HexaPDF::Layout::Style

style?(name)

Returns true if a style with the given name exists, else false.

See HexaPDF::Document::Layout#style for details; this method is just a thin wrapper around that method.

Example:

composer.style(:header, font: 'Helvetica')
composer.style?(:header)     # => true
composer.style?(:paragraph)  # => false
styles → styles
styles(**mapping) → styles

Creates multiple named styles at once if mapping is provided, and returns the style mapping.

See HexaPDF::Document::Layout#styles for details; this method is just a thin wrapper around that method.

Example:

composer.styles(
  base: {font_size: 12, leading: 1.2},
  header: {font: 'Helvetica', fill_color: "008"},
  header1: {base: :header, font_size: 30}
)

See: HexaPDF::Layout::Style

text(str, width: 0, height: 0, style: nil, box_style: nil, **style_properties)

Draws the given text at the current position into the current frame.

The text will be positioned at the current position (see x and y) if possible. Otherwise the next best position is used. If the text doesn’t fit onto the current page or only partially, one or more new pages are created automatically.

This method is of the two main methods for creating text boxes, the other being formatted_text. It uses HexaPDF::Document::Layout#text_box behind the scenes to create the HexaPDF::Layout::TextBox that does the actual work.

See HexaPDF::Document::Layout#text_box for details on the arguments.

Examples:

composer.text("Test it now " * 15)
composer.text("Now " * 7, width: 100)
composer.text("Another test", font_size: 15, fill_color: "hp-blue")
composer.text("Different box style", fill_color: 'white', box_style: {
  underlays: [->(c, b) { c.rectangle(0, 0, b.content_width, b.content_height).fill }]
})

See: formatted_text, HexaPDF::Layout::TextBox, HexaPDF::Layout::TextFragment

write(output, optimize: true, **options)

Writes the created PDF document to the given output.

See HexaPDF::Document#write for details.

write_to_string(optimize: true, **options)

Writes the created PDF document to a string and returns that string.

See HexaPDF::Document#write for details.

x()

The x-position inside the current frame where the next box (provided it fits) will be placed.

Example:

composer.text("Hello", position: :float)
composer.canvas.stroke_color("hp-blue").
  circle(composer.x, composer.y, 0.5).fill.
  circle(composer.x, composer.y, 5).stroke

y()

The y-position inside the current frame.where the next box (provided it fits) will be placed.

Example:

composer.text("Hello", position: :float)
composer.canvas.stroke_color("hp-blue").
  circle(composer.x, composer.y, 0.5).fill.
  circle(composer.x, composer.y, 5).stroke