Class | Prawn::Document
In: | lib/prawn/document/annotations.rb lib/prawn/document/bounding_box.rb lib/prawn/document/column_box.rb lib/prawn/document/destinations.rb lib/prawn/document/internals.rb lib/prawn/document/page_geometry.rb lib/prawn/document/span.rb lib/prawn/document/text/box.rb lib/prawn/document/text/wrapping.rb lib/prawn/document/text.rb lib/prawn/document.rb lib/prawn/font.rb
Parent: | Object

The Prawn::Document class is how you start creating a PDF document.

There are three basic ways you can instantiate PDF Documents in Prawn, they are through assignment, implicit block or explicit block. Below is an exmple of each type, each example does exactly the same thing, makes a PDF document with all the defaults and puts in the default font "Hello There" and then saves it to the current directory as "example.pdf"

For example, assignment can be like this:

      pdf = Prawn::Document.new
      pdf.text "Hello There"
      pdf.render_file "example.pdf"

Or you can do an implied block form:

      Prawn::Document.generate "example.pdf" do
        text "Hello There"
      end

Or if you need to access a variable outside the scope of the block, the explicit block form:

      words = "Hello There"
      Prawn::Document.generate "example.pdf" do |pdf|
        pdf.text words
      end

Usually, the block forms are used when you are simply creating a PDF document that you want to immediately save or render out.

See the new and generate methods for further details on the above.

### Methods

bounding_box bounds bounds= canvas column_box compression_enabled? cursor font font_families font_size generate move_down move_up new pad pad_bottom pad_top page_count render render_file save_font span start_new_page text_box width_of

### Included Modules

Text PageGeometry Internals Annotations Destinations Prawn::Graphics Prawn::Images

### Classes and Modules

Module Prawn::Document::Annotations
Module Prawn::Document::Destinations
Module Prawn::Document::Internals
Module Prawn::Document::PageGeometry
Module Prawn::Document::Text
Class Prawn::Document::BoundingBox
Class Prawn::Document::ColumnBox

### Attributes

font_size | [W] |
margin_box | [RW] |
margins | [R] |
page_layout | [R] |
page_size | [R] |
y | [RW] |

### Public Class methods

generate(filename,options={},&block)

Creates and renders a PDF document.

When using the implicit block form, Prawn will evaluate the block within an instance of Prawn::Document, simplifying your syntax. However, please note that you will not be able to reference variables from the enclosing scope within this block.

      # Using implicit block form and rendering to a file
      Prawn::Document.generate "example.pdf" do
        # self here is set to the newly instantiated Prawn::Document
        # and so any variables in the outside scope are unavailable
        font "Times-Roman"
        text "Hello World", :at => [200,720], :size => 32
      end

If you need to access your local and instance variables, use the explicit block form shown below. In this case, Prawn yields an instance of PDF::Document and the block is an ordinary closure:

      # Using explicit block form and rendering to a file
      content = "Hello World"
      Prawn::Document.generate "example.pdf" do |pdf|
        # self here is left alone
        pdf.font "Times-Roman"
        pdf.text content, :at => [200,720], :size => 32
      end

new(options={},&block)

Additionally, :page_size can be specified as a simple two value array giving the width and height of the document you need in PDF Points.

Usage:

      # New document, US Letter paper, portrait orientation
      pdf = Prawn::Document.new

      # New document, A4 paper, landscaped
      pdf = Prawn::Document.new(:page_size => "A4", :page_layout => :landscape)

      # New document, Custom size
      pdf = Prawn::Document.new(:page_size => [200, 300])

      # New document, with background
      pdf = Prawn::Document.new(:background => "#{Prawn::BASEDIR}/data/images/pigs.jpg")

### Public Instance methods

bounding_box(point, options={}, &block)

A bounding box serves two important purposes:

- Provide bounds for flowing text, starting at a given point
- Translate the origin (0,0) for graphics primitives, for the purposes

of simplifying coordinate math.

## Positioning

Bounding boxes are positioned relative to their top left corner and the width measurement is towards the right and height measurement is downwards.

Usage:

- Bounding box 100pt x 100pt in the absolutle bottom left of the containing

box:

     pdf.bounding_box([0,100], :width => 100, :height => 100)
       stroke_bounds
     end

- Bounding box 200pt x 400pt high in the center of the page:

     x_pos = ((bounds.width / 2) - 150)
     y_pos = ((bounds.height / 2) + 200)
     pdf.bounding_box([x_pos, y_pos], :width => 300, :height => 400) do
       stroke_bounds
     end

## Flowing Text

When flowing text, the usage of a bounding box is simple. Text will begin at the point specified, flowing the width of the bounding box. After the block exits, the cursor position will be moved to the bottom of the bounding box (y - height). If flowing text exceeds the height of the bounding box, the text will be continued on the next page, starting again at the top-left corner of the bounding box.

Usage:

      pdf.bounding_box([100,500], :width => 100, :height => 300) do
        pdf.text "This text will flow in a very narrow box starting" +
         "from [100,500]. The pointer will then be moved to [100,200]" +
         "and return to the margin_box"
      end

## Translating Coordinates

When translating coordinates, the idea is to allow the user to draw relative to the origin, and then translate their drawing to a specified area of the document, rather than adjust all their drawing coordinates to match this new region.

Take for example two triangles which share one point, drawn from the origin:

      pdf.polygon [0,250], [0,0], [150,100]
      pdf.polygon [100,0], [150,100], [200,0]

It would be easy enough to translate these triangles to another point, e.g [200,200]

      pdf.polygon [200,450], [200,200], [350,300]
      pdf.polygon [300,200], [350,300], [400,200]

However, each time you want to move the drawing, you‘d need to alter every point in the drawing calls, which as you might imagine, can become tedious.

If instead, we think of the drawing as being bounded by a box, we can see that the image is 200 points wide by 250 points tall.

To translate it to a new origin, we simply select a point at (x,y+height)

Using the [200,200] example:

      pdf.bounding_box([200,450], :width => 200, :height => 250) do
        pdf.stroke do
          pdf.polygon [0,250], [0,0], [150,100]
          pdf.polygon [100,0], [150,100], [200,0]
        end
      end

Notice that the drawing is still relative to the origin. If we want to move this drawing around the document, we simply need to recalculate the top-left corner of the rectangular bounding-box, and all of our graphics calls remain unmodified.

## Nesting Bounding Boxes

By default, bounding boxes are specified relative to the document‘s margin_box (which is itself a bounding box). You can also nest bounding boxes, allowing you to build components which are relative to each other

Usage:

     pdf.bounding_box([200,450], :width => 200, :height => 250) do
       pdf.stroke_bounds   # Show the containing bounding box
       pdf.bounding_box([50,200], :width => 50, :height => 50) do
         # a 50x50 bounding box that starts 50 pixels left and 50 pixels down
         # the parent bounding box.
         pdf.stroke_bounds
       end
     end

## Stretchyness

If you do not specify a height to a boundng box, it will become stretchy and it‘s height will be calculated according to the last drawing position within the bounding box:

     pdf.bounding_box([100,400], :width => 400) do
       pdf.text("The height of this box is #{pdf.bounds.height}")
       pdf.text('this is some text')
       pdf.text('this is some more text')
       pdf.text('and finally a bit more')
       pdf.text("Now the height of this box is #{pdf.bounds.height}")
     end

## Absolute Positioning

If you wish to position the bounding boxes at absolute coordinates rather than relative to the margins or other bounding boxes, you can use canvas()

     pdf.bounding_box([50,500], :width => 200, :height => 300) do
       pdf.stroke_bounds
       pdf.canvas do
         pdf.bounding_box([300,450], :width => 200, :height => 200) do
           # Positioned outside the containing box at the 'real' (300,450)
           pdf.stroke_bounds
         end
       end
     end

Of course, if you use canvas, you will be responsible for ensuring that you remain within the printable area of your document.

bounds()

The bounds method returns the current bounding box you are currently in, which is by default the box represented by the margin box on the document itself. When called from within a created `bounding_box` block, the box defined by that call will be returned instead of the document margin box.

Another important point about bounding boxes is that all x and y measurements within a bounding box code block are relative to the bottom left corner of the bounding box.

For example:

     Prawn::Document.new do
       # In the default "margin box" of a Prawn document of 0.5in along each edge

       # Draw a border around the page (the manual way)
       stroke do
         line(bounds.bottom_left, bounds.bottom_right)
         line(bounds.bottom_right, bounds.top_right)
         line(bounds.top_right, bounds.top_left)
         line(bounds.top_left, bounds.bottom_left)
       end

       # Draw a border around the page (the easy way)
       stroke_bounds
     end

bounds=(bounding_box)

Sets Document#bounds to the BoundingBox provided. See above for a brief description of what a bounding box is. This function is useful if you really need to change the bounding box manually, but usually, just entering and existing bounding box code blocks is good enough.

canvas(&block)

A shortcut to produce a bounding box which is mapped to the document‘s absolute coordinates, regardless of how things are nested or margin sizes.

      pdf.canvas do
        pdf.line pdf.bounds.bottom_left, pdf.bounds.top_right
      end

column_box(*args, &block)

A column box is a bounding box with the additional property that when text flows past the bottom, it will wrap first to another column on the same page, and only flow to the next page when all the columns are filled.

column_box accepts the same parameters as bounding_box, as well as the number of :columns and a :spacer (in points) between columns.

Defaults are :columns = 3 and :spacer = font_size

Under PDF::Writer, "spacer" was known as "gutter"

compression_enabled?()

Returns true if content streams will be compressed before rendering, false otherwise

cursor()

The current y drawing position relative to the innermost bounding box, or to the page margins at the top level.

font(name=nil, options={}) {|| ...}

Without arguments, this returns the currently selected font. Otherwise, it sets the current font.

The single parameter must be a string. It can be one of the 14 built-in fonts supported by PDF, or the location of a TTF file. The Font::AFM::BUILT_INS array specifies the valid built in font values.

      pdf.font "Times-Roman"
      pdf.font "Chalkboard.ttf"

If a ttf font is specified, the glyphs necessary to render your document will be embedded in the rendered PDF. This should be your preferred option in most cases. It will increase the size of the resulting file, but also make it more portable.

font_families()

Hash that maps font family names to their styled individual font names

To add support for another font family, append to this hash, e.g:

      pdf.font_families.update(
       "MyTrueTypeFamily" => { :bold        => "foo-bold.ttf",
                               :italic      => "foo-italic.ttf",
                               :bold_italic => "foo-bold-italic.ttf",
                               :normal      => "foo.ttf" })

This will then allow you to use the fonts like so:

      pdf.font("MyTrueTypeFamily", :style => :bold)
      pdf.text "Some bold text"
      pdf.font("MyTrueTypeFamily")
      pdf.text "Some normal text"

This assumes that you have appropriate TTF fonts for each style you wish to support.

font_size(points=nil) {|: return| ...}

When called with no argument, returns the current font size. When called with a single argument but no block, sets the current font size. When a block is used, the font size is applied transactionally and is rolled back when the block exits. You may still change the font size within a transactional block for individual text segments, or nested calls to font_size.

      Prawn::Document.generate("font_size.pdf") do
        font_size 16
        text "At size 16"

        font_size(10) do
          text "At size 10"
          text "At size 6", :size => 6
          text "At size 10"
        end

        text "At size 16"
      end

When called without an argument, this method returns the current font size.

move_down(n)

Moves down the document by n points relative to the current position inside the current bounding box.

move_up(n)

Moves up the document by n points relative to the current position inside the current bounding box.

pad(y) {|| ...}

Moves down the document by y, executes a block, then moves down the document by y again.

      pdf.text "some text"
      pdf.pad(100) do
        pdf.text "This is 100 points below the previous line of text"
      end
      pdf.text "This is 100 points below the previous line of text"

pad_bottom(y) {|| ...}

Executes a block then moves down the document

      pdf.text "some text"
      pdf.pad_bottom(100) do
        pdf.text "This text appears right below the previous line of text"
      end
      pdf.text "This is 100 points below the previous line of text"

pad_top(y) {|| ...}

Moves down the document and then executes a block.

      pdf.text "some text"
      pdf.pad_top(100) do
        pdf.text "This is 100 points below the previous line of text"
      end
      pdf.text "This text appears right below the previous line of text"

page_count()

Returns the number of pages in the document

      pdf = Prawn::Document.new
      pdf.page_count #=> 1
      3.times { pdf.start_new_page }
      pdf.page_count #=> 4

render()

Renders the PDF document to string, useful for example in a Rails application where you want to stream out the PDF to a web browser:

     def show
       pdf = Prawn::Document.new do
         text "Putting PDF generation code in a controller is _BAD_"
       end
       send(pdf.render, :filename => 'silly.pdf', :type => 'application/pdf', :disposition => 'inline)
     end

render_file(filename)

Renders the PDF document to file.

      pdf.render_file "foo.pdf"

save_font() {|| ...}

Saves the current font, and then yields. When the block finishes, the original font is restored.

span(width, options={})

A span is a special purpose bounding box that allows a column of elements to be positioned relative to the margin_box.

Arguments:

`width`: | The width of the column in PDF points

Options:

`:position`: | One of :left, :center, :right or an x offset

This method is typically used for flowing a column of text from one page to the next.

     span(350, :position => :center) do
       text "Here's some centered text in a 350 point column. " * 100
     end

start_new_page(options = {})

Creates and advances to a new page in the document.

Page size, margins, and layout can also be set when generating a new page. These values will become the new defaults for page creation

      pdf.start_new_page #=> Starts new page keeping current values
      pdf.start_new_page(:size => "LEGAL", :layout => :landscape)
      pdf.start_new_page(:left_margin => 50, :right_margin => 50)

text_box(text,options)

Defines an invisible rectangle which you can flow text in. When the text overflows the box, you can either display :ellipses, :truncate the text, or allow it to overflow the bottom boundary with :expand.

      text_box "Oh hai text box. " * 200,
        :width    => 300, :height => font.height * 5,
        :overflow => :ellipses,
        :at       => [100,bounds.top]

width_of(string, options={})

Returns the width of the given string using the given font. If :size is not specified as one of the options, the string is measured using the current font size. You can also pass :kerning as an option to indicate whether kerning should be used when measuring the width (defaults to `false`).

Note that the string must be encoded properly for the font being used. For AFM fonts, this is WinAnsi. For TTF, make sure the font is encoded as UTF-8. You can use the Font#normalize_encoding method to make sure strings are in an encoding appropriate for the current font.

[Validate]