prawn-svg

prawn-svg

An SVG renderer for the Prawn PDF library.

This will take an SVG document as input and render it into your PDF. Find out more about the Prawn PDF library at:

http://github.com/prawnpdf/prawn

prawn-svg is compatible with all versions of Prawn from 0.11.1 onwards, including the 1.x and 2.x series. The minimum Ruby version required is 2.7.

Using prawn-svg

Prawn::Document.generate("test.pdf") do
  svg '<svg><rect width="100" height="100" fill="red"></rect></svg>'
end

prawn-svg will do something sensible if you call it with only an SVG document, but you can also pass the following options to tailor its operation:

Option	Data type	Description
:at	[integer, integer]	Specify the location on the page you want the SVG to appear.
:position	:left, :center, :right, integer	If :at not specified, specifies the horizontal position to show the SVG. Defaults to :left.
:vposition	:top, :center, :bottom, integer	If :at not specified, specifies the vertical position to show the SVG. Defaults to current cursor position.
:width	integer	Desired width of the SVG. Defaults to horizontal space available.
:height	integer	Desired height of the SVG. Defaults to vertical space available.
:enable_web_requests	boolean	If true, prawn-svg will make http and https requests to fetch images. Defaults to true.
:enable_file_requests_with_root	string	If not nil, prawn-svg will serve file: URLs from your local disk if the file is located under the specified directory. It is very dangerous to specify the root path ("/") if you're not fully in control of your input SVG. Defaults to nil (off).
:cache_images	boolean	If true, prawn-svg will cache the result of all URL requests. Defaults to false.
:fallback_font_name	string	A font name which will override the default fallback font of Times-Roman. If this value is set to nil, prawn-svg will ignore a request for an unknown font and log a warning.
:color_mode	:rgb, :cmyk	Output color mode. Defaults to :rgb.

Examples

  # Render the logo contained in the file logo.svg at 100, 100 with a width of 300
  svg IO.read("logo.svg"), at: [100, 100], width: 300

  # Render the logo at the current Y cursor position, centered in the current bounding box
  svg IO.read("logo.svg"), position: :center

  # Render the logo at the current Y cursor position, and serve file: links relative to its directory
  root_path = "/apps/myapp/current/images"
  svg IO.read("#{root_path}/logo.svg"), enable_file_requests_with_root: root_path

Supported features

prawn-svg supports most but not all of the full SVG 1.1 specification. It currently supports:

• <line>, <polyline>, <polygon>, <circle> and <ellipse>

• <rect>. Rounded rects are supported, but only one radius is applied to all corners.

• <path> supports all commands defined in SVG 1.1, although the implementation of elliptical arc is a bit rough at the moment.

• <text>, <tspan> and <tref> with attributes x, y, dx, dy, rotate, textLength, lengthAdjust, and with extra properties text-anchor, text-decoration (underline only), font-size, font-family, font-weight, font-style, letter-spacing, dominant-baseline (middle only)

• <svg>, <g> and <symbol>

• <use>

• <style> (see CSS section below)

• <image> referencing a JPEG, PNG, or SVG image, with http:, https:, data:image/jpeg;base64, data:image/png;base64, data:image/svg+xml;base64 and file: schemes (file: is disabled by default for security reasons, see Options section above)

• <clipPath>

• <marker>

• <linearGradient> and <radialGradient> are implemented on Prawn 2.2.0+ with attributes gradientUnits and gradientTransform (spreadMethod and stop-opacity are unimplemented.)

• <switch> and <foreignObject>, although prawn-svg cannot handle any data that is not SVG so <foreignObject> tags are always ignored.

• properties: clip-path, color, display, fill, fill-opacity, fill-rule, opacity, overflow, stroke, stroke-dasharray, stroke-linecap, stroke-linejoin, stroke-opacity, stroke-width

• properties on lines, polylines, polygons and paths: marker-end, marker-mid, marker-start

• attributes on all elements: class, id, style, transform, xml:space

• the viewBox attribute on <svg> and <marker> elements

• the preserveAspectRatio attribute on <svg>, <image> and <marker> elements

• transform methods: translate, translateX, translateY, rotate, scale, skewX, skewY, matrix

• colors: HTML standard names, #xxx, #xxxxxx, rgb(1, 2, 3), rgb(1%, 2%, 3%), and also the non-standard device-cmyk(1, 2, 3, 4) for CMYK colors

• measurements specified in pt, cm, dm, ft, in, m, mm, yd, pc, %

• fonts: generic CSS fonts, built-in PDF fonts, and any TTF fonts in your fonts path, specified in any of the measurements above plus em or rem

CSS

prawn-svg supports CSS, both in <style> blocks and style attributes.

In CSS selectors you can use element names, IDs, classes, attributes (existence, =, ^=, $=, *=, ~=, |=) and all combinators ( , >, +, ~). The pseudo-classes :first-child, :last-child and :nth-child(n) (where n is a number) also work.

Warning: Ruby versions less than 2.6.0 have a bug in the REXML XPath implementation which means under some conditions the + combinator will not pick up all matching elements. See stylesheets_spec.rb for an explanation if you're stuck on an old version of Ruby.

Pseudo-elements and the other pseudo-classes are not supported. Specificity ordering is implemented, but !important is not.

Not supported

prawn-svg does not support hyperlinks, patterns, masks or filters.

It does not support text in the clip area, but you can clip shapes and text by any shape.

Configuration

Fonts

By default, prawn-svg has a fonts path of ["/Library/Fonts", "/System/Library/Fonts", "#{ENV["HOME"]}/Library/Fonts", "/usr/share/fonts/truetype"] to catch MacOS and Debian Linux users. You can add to the font path:

  Prawn::SVG::FontRegistry.font_path << "/my/font/directory"

Using with prawn-rails

In your Gemfile, put gem 'prawn-svg' before gem 'prawn-rails' so that prawn-rails can see the prawn-svg extension.

Licence

MIT licence. Copyright Mog Nesbitt.