PSD.rb

A general purpose Photoshop file parser written in Ruby. It allows you to work with a Photoshop document in a manageable tree structure and find out important data such as:

• Document structure
• Document size
• Layer/folder size + positioning
• Layer/folder names
• Layer/folder visibility and opacity
• Font data (via psd-enginedata)
  • Text area contents
  • Font names, sizes, and colors
• Color mode and bit-depth
• Vector mask data
• Flattened image data
• Layer comps

PSD.rb is tested against:

• MRI 1.9.3, 2.0.0, 2.1.0
• JRuby (1.9.3 mode)

If you use MRI Ruby and are interested in significantly speeding up PSD.rb with native code, check out psd_native.

Installation

Add this line to your application's Gemfile:

gem 'psd'

And then execute:

$ bundle

Or install it yourself as:

$ gem install psd

Usage

The full source code documentation is available, but here are some common ways to use and access the PSD data:

Loading a PSD

require 'psd'

psd = PSD.new('/path/to/file.psd')
psd.parse!

Or, if you prefer the File.open way of doing things, you can do that too.

require 'psd'

PSD.open('path/to/file.psd') do |psd|
  p psd.tree.to_hash
end

As you can see, open calls parse! for you, so that you can get down to business right away.

If you happen to prefer things DSL-style, the open method will also let you operate on the PSD object directly. Again, the call to parse! is handled for you.

require 'psd'

PSD.open('path/to/file.psd') do
  p tree.to_hash
end

Traversing the Document

To access the document as a tree structure, use psd.tree to get the root node. From there, work with the tree using any of these methods:

• root: get the root node from anywhere in the tree
• root?: is this the root node?
• children: get all immediate children of the node
• has_children?: does this node have any children?
• childless?: opposite of has_children?
• ancestors: get all ancestors in the path of this node (excluding the root)
• siblings: get all sibling tree nodes including the current one (e.g. all layers in a folder)
• next_sibling: gets the sibling immediately following the current node
• prev_sibling: gets the sibling immediately before the current node
• has_siblings?: does this node have any siblings?
• only_child?: opposite of has_siblings?
• descendants: get all descendant nodes not including the current one
• subtree: same as descendants but starts with the current node
• depth: calculate the depth of the current node (root node is 0)
• path: gets the path to the current node

For any of the traversal methods, you can also retrieve folder or layer nodes only by appending _layers or _groups to the method. For example:

psd.tree.descendant_layers

If you know the path to a group or layer within the tree, you can search by that path. Note that this always returns an Array because layer/group names do not have to be unique.

psd.tree.children_at_path("Version A/Matte")
psd.tree.children_at_path(["Version A", "Matte"])

Layer Comps

You can also filter nodes based on a layer comp. To generate a new tree with layer visibility and position set according to the layer comp data:

# Get information about all the available layer comps
puts psd.layer_comps

# Can filter by name or by ID (obtained from above)
tree = psd.tree.filter_by_comp('Version A')
puts tree.children.map(&:name)

This returns a new node tree and does not alter the original.

Accessing Layer Data

To get data such as the name or dimensions of a layer:

psd.tree.descendant_layers.first.name
psd.tree.descendant_layers.first.width

PSD files also store various pieces of information in "layer info" blocks. Which blocks a layer has varies from layer-to-layer, but to access them you can do:

psd.tree.descendant_layers.first.text[:font]

# Returns
{:name=>"HelveticaNeue-Light",
 :sizes=>[33.0],
 :colors=>[[255, 19, 120, 98]],
 :css=>
  "font-family: \"HelveticaNeue-Light\", \"AdobeInvisFont\", \"MyriadPro-Regular\";\nfont-size: 33.0pt;\ncolor: rgba(19, 120, 98, 255);"}

Exporting Data

When working with the tree structure, you can recursively export any node to a Hash.

pp psd.tree.to_hash

Which produces something like:

{:children=>
  [{:type=>:group,
    :visible=>false,
    :opacity=>1.0,
    :blending_mode=>"normal",
    :name=>"Version D",
    :left=>0,
    :right=>900,
    :top=>0,
    :bottom=>600,
    :height=>900,
    :width=>600,
    :children=>
     [{:type=>:layer,
       :visible=>true,
       :opacity=>1.0,
       :blending_mode=>"normal",
       :name=>"Make a change and save.",
       :left=>275,
       :right=>636,
       :top=>435,
       :bottom=>466,
       :height=>31,
       :width=>361,
       :text=>
        {:value=>"Make a change and save.",
         :font=>
          {:name=>"HelveticaNeue-Light",
           :sizes=>[33.0],
           :colors=>[[255, 19, 120, 98]],
           :css=>
            "font-family: \"HelveticaNeue-Light\", \"AdobeInvisFont\", \"MyriadPro-Regular\";\nfont-size: 33.0pt;\ncolor: rgba(19, 120, 98, 255);"},
         :left=>0,
         :top=>0,
         :right=>0,
         :bottom=>0,
         :transform=>
          {:xx=>1.0, :xy=>0.0, :yx=>0.0, :yy=>1.0, :tx=>456.0, :ty=>459.0}},
       :ref_x=>264.0,
       :ref_y=>-3.0}]
  }],
:document=>{:width=>900, :height=>600}}

You can also export the PSD to a flattened image. Please note that, at this time, not all image modes + depths are supported.

png = psd.image.to_png # reference to PNG data
psd.image.save_as_png 'path/to/output.png' # writes PNG to disk

This uses the full rasterized preview provided by Photoshop. It does not use the built-in rendering engine (described below). If the file was not saved with Compatibility Mode enabled, this will return an empty image.

Preview Building

You can build previews of any subset or version of the PSD document using the built-in renderer. This is useful for generating previews of layer comps or exporting individual layer groups as images.

# Save a layer comp
psd.tree.filter_by_comp("Version A").save_as_png('./Version A.png')

# Generate PNG of individual layer group
psd.tree.children_at_path("Group 1").first.to_png

Slices

Because slices are relative to the full document, you can access them directly on the psd object. Use psd.slices to get an array of all slices in the document.

slices = psd.slices
slices.first.name #=> "Logo"
slices.first.left #=> 20
slices.first.width #=> 200

You can also search for slices if you know their name or ID. Because slice names do not need to be unique, slices_by_name will always return an array of all matches.

psd.slice_by_id(2)
psd.slices_by_name('Logo')

When you create a slice based off of a layer, Photoshop stores this relation in the file. If you have a slice that was created this way, you can easily get the associated layer.

slice = psd.slices_by_name('Logo').first
slice.associated_layer #=> <PSD::Node::Layer>

Finally, you can export slices as PNGs.

psd.slices.first.to_png #=> ChunkyPNG canvas
psd.slices_by_name('Logo').first.save_as_png('Logo.png') #=> writes Logo.png

Debugging

If you run into any problems parsing a PSD, you can enable debug logging via the PSD_DEBUG environment variable. For example:

PSD_DEBUG=true bundle exec examples/parse.rb

If you need to enable debugging programatically:

PSD.debug = true

To-do

There are a few features that are currently missing from PSD.rb.

• More image modes + depths for image exporting
• Support for rendering all layer styles
• Support for layer comp adjusted layer styles
• Render engine fixes for groups with lowered opacity