casaval / squib

A Ruby DSL for prototyping card games.

Squib

Squib is a Ruby DSL for prototyping card and board games. Write a little bit of Ruby, define your deck's stats, then compile your game into a series of images ready for print-and-play or even print-on-demand. Squib is very data-driven and built on the principle of Don't Repeat Yourself. Think of it like nanDeck done "the Ruby way". Squib supports:

• A concise set of rules for laying out your cards
• Loading PNGs and SVGs
• Complex text rendering using Pango
• Reading xlsx and csv files
• Rendering to PNGs, PDFs, and SVGs (sheets or individual files)
• Flexible, data-driven layouts in Yaml
• Basic shape drawing, blending operators, gradients, etc.
• Unit conversion
• The full power of Ruby!

Squib is based on the Cairo graphics rendering engine, the library of choice for WebKit, Gecko, Inkscape and many, many others.

Check this out.

require 'squib'

Squib::Deck.new(cards: 2) do
  text str: %w(Hello World!)
  save_png
end

We just created a 2-card deck with "Hello" on the first card, and "World" on the second, and saved them out to PNGs.

Installation

Install it yourself with:

$ gem install squib

If you're using Bundler, add this line to your application's Gemfile:

gem 'squib'

And then execute:

$ bundle

Note: Squib has some native dependencies, such as Cairo, Pango, and Nokogiri, which may require compiling C code to install. This is usually not painful at all, but can cause headaches on some setups.

• Windows: I strongly recommend using the non-64 bit RubyInstaller at http://rubyinstaller.org along with installing DevKit.
• Mac: I recommend using rvm.
• Cywgin is not 100% supported, but could potentially work with extra installation steps. See this thread

Squib requires Ruby 2.0 or later.

Getting Started

After installing Squib, you can create a project and run your first build like this:

$ squib new my-cool-game
$ cd my-cool-game
$ ruby deck.rb

The squib new command will generate files and folders like this:

_output/gitkeep.txt
.gitignore
ABOUT.md
config.yml
deck.rb
Gemfile
layout.yml
PNP NOTES.md

The central file here is deck.rb. Here's a basic example of a deck to work from:

{include:file:samples/basic.rb basic.rb}

About the other files:

• Gemfile is for adding in other gems if you are using bundler
• config.yml is a skeleton config file with various options commented out. See {file:README.md#Configuration_File Configuration File}.
• layout.yml is a skeleton layout file if you want to use it. See {file:README.md#Custom_Layouts Custom Layouts}.
• _output is the directory where your built files will go. Can easily be changed, of course.
• .gitignore and gitkeep.txt are for if you are using Git. See {file:README.md#Source_control Source control}. (Feel free to remove these if you are not using Git.)
• ABOUT.md and PHP NOTES.md are Markdown files for posting. Not used by Squib, but there by convention.
• Rakefile is a basic build file. Not required but handy - see {file:README.md#Rakefile Rakefile}

Learning Squib

In addition to this README, be sure to also check out the following resources for more details:

• The samples directory in the source repository has lots of examples.
• Iconoclast is a basic set collection game I'm developing from scratch with Squib. Be sure to read the commit history to see how the game has developed from scratch.
• Junk Land is my own creation that's uses Squib for full-color rendering, and makes use of Ruby in a lot of interesting ways.

Viewing this README

The best place to read this documentation is on our website. Be sure to check out the method-by-method documentation, particularly for the Deck class.

If you want to view it offline, you can do the following

$ gem install yard
$ yard server --gems

Then go to http://localhost:8808/docs/squib/file/README.md

If you're viewing this on Github, you might see some confusing tags like {include:file:...} - these are directives for YARD to show the embedded examples. Github doesn't render those and you might find them helpful.

Also, RubyDoc.info linked from RubyGems appears to be perpetually broken and doesn't support {include:file...} directive properly, so the embedded samples will also not show up there, either.

Squib Decks and Cards

The Squib DSL is based on a collection of methods provided to the Squib::Deck class. The general philosophy of Squib is to specify as little as possible with layers of defaults, highly flexible input, and good ol' Ruby duck-typing. Ruby does a lot to make Squib useful.

Squib essentially has two main classes: Deck and Card. Deck is the front-end, and Card is the back-end. The contract of Deck is to do the various manipulations of options and then delegate the operation to Card to do the low-level graphical operations.

For most users, I recommending solely using Deck methods. If you want to roll up your sleeves and get your hands messy, you can access the Cairo or Pango contexts the directly via the Card class. The API documentation doesn't really cover these, however, so you're on your own there.

Specifying Parameters

Squib is all about sane defaults and shorthand specification. Arguments are almost always using hashes, which look a lot like Ruby 2.0's named parameters. This means you can specify your parameters in any order you please. All parameters are optional. For example x and y default to 0 (i.e. the upper-left corner of the card). Any parameter that is specified in the command overrides any Squib defaults, config.yml settings, or layout rules.

Note: you MUST use named parameters rather than positional parameters. For example: save :png will lead to an error like this:

C:/Ruby200/lib/ruby/gems/2.0.0/gems/squib-0.0.3/lib/squib/api/save.rb:12:in `save': wrong number of arguments (2 for 0..1) (ArgumentError)
    from deck.rb:22:in `block in <main>'
    from C:/Ruby200/lib/ruby/gems/2.0.0/gems/squib-0.0.3/lib/squib/deck.rb:60:in `instance_eval'
    from C:/Ruby200/lib/ruby/gems/2.0.0/gems/squib-0.0.3/lib/squib/deck.rb:60:in `initialize'
    from deck.rb:18:in `new'
    from deck.rb:18:in `<main>'

Instead, you must name the parameters: save format: :png

Arrays and Singleton Expansion

Many inputs to Squib can accept Arrays, which correspond to the entire deck. In fact, under the hood, if Squib is not given an array, it expands it out to an array before rendering. This allows for different styles to apply to different cards. This example comes from the ranges.rb example

# This renders three cards, with three strings that had three different colors at three different locations.
text str: %w(red green blue),
     color: [:red, :green, :blue],
     x: [40, 80, 120],
     y: [700, 750, 800]

Under the hood, Squib actually views every argument as applied each card individually. If a single argument is given to the command, it's considered a singleton that gets expanded into a deck-sized array. Supplying the array bypasses that expansion - which means that any array you supply instead of a singleton ought to be the same size as the deck and align the same way the indexes in the supplied range are. If you don't, Ruby will fill that up with nils and not apply the rule across those cards.

Specifying Ranges

Most public Deck methods allow a range to be specified as a first parameter. This parameter is used to access an internal Array of Squib::Cards. This can be an actual Ruby range, or anything that implements #each (thus can be an Enumerable). Integers are also supported for changing one card only. Negatives work from the back of the deck. Here are some examples from samples/ranges.rb found here

{include:file:samples/ranges.rb}

Units

By default, Squib thinks in pixels. This decision was made so that we can have pixel-perfect layouts without automatically scaling everything, even though working in units is sometimes easier. We provide some conversion methods, including looking for strings that end in "in" and "cm" and computing based on the current DPI. The dpi is set on Squib::Deck.new (not config.yml). Example is in samples/units.rb found here

{include:file:samples/units.rb}

Specifying Colors & Gradients

Colors can be specified in a wide variety of ways, mostly in a hex-string. Take a look at the examples from samples/colors.rb, found here

{include:file:samples/colors.rb}

Under the hood, Squib uses the rcairo color parser to accept a variety of color specifications, along with over 300 pre-defined constants. The above sample will generate a table of such constants.

Additionally, in most places where colors are allowed, you may also supply a string that defines a gradient. Squib supports two flavors of gradients: linear and radial. Gradients are specified by supplying some xy coordinates, which are relative to the card (not the command). Each stop must be between 0.0 and 1.0, and you can supply as many as you like. Colors can be specified as above (in any of the hex notations or built-in constant). If you add two (or more) colors at the same stop, then the gradient keeps the colors in the in order specified and treats it like sharp transition.

The format for gradient strings look like this:

Linear:

(x1,y1)(x2,y2) color1@stop1 color2@stop2

The xy coordinates define the angle of the gradient.

Radial:

(x1,y1,radius1)(x2,y2,radius2) color1@stop1 color2@stop2

The coordinates specify an inner circle first, then an outer circle.

Check out the following sample from samples/gradients.rb, found here

{include:file:samples/gradients.rb}

Specifying Files

All files opened for reading or writing (e.g. for png and xlsx) are opened relative to the current directory. Files opened for writing (e.g. for save_png) will be overwritten without warning.

If you find that you cd a lot while working on the command line, your _output folder might get generated in multiple places. An easy way to fix this is to use a Rakefile, see below

Working with Text

The text method is a particularly powerful method with a ton of options. Be sure to check the API docs on an option-by-option discussion, but here are the highlights.

Fonts. The font is specified in a given Pango "font string", which can involve a ton of options embedded there in the string. In addition to the typical bold and italic variations, you can also specify all-caps, the specific boldness weight (e.g. 900), or go with oblique. These options are only available if the underlying font supports them, however. Here's are some example Pango font strings:

Sans 18
Arial,Verdana weight=900 style=oblique 36
Times New Roman,Sans 25

Note: When the font has a space it, you'll need to put a backup to get Pango's parsing to work.

It's also important to note that most of the font rendering is done by a combination of your installed fonts, your OS, and your graphics card. Thus, different systems will render text slightly differently.

Furthermore, options like font_size allow you to override the font string. This means that you can set a blanket font for the whole deck, then adjust sizes from there. This is useful with layouts and extends too.

Width and Height

By default, Pango text boxes will scale the text box to whatever you need, hence the :native default. However, for most of the other customizations to work (e.g. center-aligned) you'll need to specify the width. If both the width and the height are specified and the text overflows, then the ellipsize option is consulted to figure out what to do with the overflow. Also, the valign will only work if height is also set to something other than :native.

###Hints

Laying out text by typing in numbers can be confusing. What Squib calls "hints" is merely a rectangle around the text box. Hints can be turned on globally in the config file, using the set method, or in an individual text method. These are there merely for prototyping and are not intended for production. Additionally, these are not to be conflated with "rendering hints" that Pango and Cairo mention in their documentation.

###Extents

Sometimes you want size things based on the size of your rendered text. For example, drawing a rectangle around card's title such that the rectangle perfectly fits. Squib returns the final rendered size of the text so you can work with it afterward. It's an array of hashes that correspond to each card. The output looks like this:

Squib::Deck.new(cards: 2) do
  extents = text(str: ['Hello', 'World!'])
  p extents
end

Will output:

[{:width=>109, :height=>55}, {:width=>142, :height=>55}] # Hello was 109 pixels wide, World 142 pixels

###Embedding Images

Squib can embed icons into the flow of text. To do this, you need to define text keys for Squib to look for, and then the corresponding files. The object given to the block is a TextEmbed, which supports PNG and SVG. Here's a minimal example:

text(str: 'Gain 1 :health:') do |embed|
  embed.svg key: ':health:', file: 'heart.svg'
end

###Markup

If you want to do specialized formatting within a given string, Squib has lots of options. By setting markup: true, you enable tons of text processing. This includes:

• Pango Markup. This is an HTML-like formatting language that specifies formatting inside your string. Pango Markup essentially supports any formatting option, but on a letter-by-letter basis. Such as: font options, letter spacing, gravity, color, etc. See the Pango docs for details.
• Quotes are converted to their curly counterparts where appropriate (i.e. “smart quotes” instead of "straight quotes").
• Apostraphes are converted to curly as well.
• LaTeX-style quotes are explicitly converted (``like this'')
• Em-dash and en-dash are converted with triple and double-dashes respectively (-- is an en-dash, and --- becomes an em-dash.)
• Ellipses can be specified with .... Note that this is entirely different from the ellipsize option (which determines what to do with overflowing text).

A few notes:

• Smart quoting assumes the UTF-8 character set.
• Pango markup uses an XML/HTML-ish processor. Some characters require HTML-entity escaping (e.g. & for `&')

Text Sample

  lsquote: "\u2018" #note that Yaml wants double quotes here to use escape chars
  rsquote: "\u2019"
  ldquote: "\u201C"
  rdquote: "\u201D"
  em_dash: "\u2014"
  en_dash: "\u2013"
  ellipsis: "\u2026"

You can also disable the auto-quoting mechanism by setting smart_quotes: false in your config. Explicit replacements will still be performed.

Text Samples

Examples of all of the above are crammed into the text_options.rb sample found here.

{include:file:samples/text_options.rb}

The embed_text.rb sample has more examples of embedding text, which can be found here.

{include:file:samples/embed_text.rb}

The config_text_markup.rb sample demonstrates how quoting can be configured, found here

{include:file:samples/config_text_markup.rb}

Custom Layouts

Working with x-y coordinates all the time can be tiresome, and ideally everything in a game prototype should be data-driven and easily changed. For this, many Squib methods allow for a layout to be set. In essence, layouts are a way of setting default values for any argument given to the command.

To use a layout, set the layout: option on a Deck.new command to point to a YAML file. Any command that allows a layout option can be set with a Ruby symbol or String, and the command will then load the specified x, y, width, and height. The individual command can also override these options.

Instead of this:

# deck.rb
Squib::Deck.new(layout: 'custom-layout.yml') do
  rect x: 75, y: 75, width: 675, height: 975
end

You can put your logic in the layout file and reference them:

# custom-layout.yml
frame:
  x: 75
  y: 75
  width: 975
  height: 675

Then your script looks like this:

# deck.rb
Squib::Deck.new(layout: 'custom-layout.yml') do
  rect layout: 'frame'
end

The goal is to make your Ruby code more separate data from logic, which in turn makes your code more readable and maintainable. With extends (see below), layouts become even more powerful in keeping you from repeating yourself.

Note: YAML is very finnicky about not allowing tab characters. Use two spaces for indentation instead. If you get a Psych syntax error, this is likely the culprit. Indendation is also strongly enforced in Yaml too. See the Yaml docs.

Order of Precedence

Layouts will override Squib's system defaults, but are overriden by anything specified in the command itself. Thus, the order of precedence looks like this:

• Use what the command specified
• If anything was not yet specified, use what was given in a layout (if a layout was specified in the command and the file was given to the Deck)
• If still anything was not yet specified, use what was given in Squib's defaults.

Special key: extends

Squib provides a way of reusing layouts with the special extends key. When defining an extends key, we can merge in another key and modify data coming in if we want to. This allows us to do things like place text next to an icon and be able to move them with each other. Like this:

# If we change the xy of attack, we move defend too!
attack:
  x: 100
  y: 100
  radius: 100
defend:
  extends: attack
  x: += 50
  #defend now is {:x => 150, :y => 100}

If you want to extend multiple parents, it looks like this:

socrates:
  x: 100
plato:
  y: 200
aristotle:
  extends:
    - socrates
    - plato
  x: += 50

If multiple keys override the same keys in a parent, the later ("younger") child takes precedent.

Note that extends keys are similar to Yaml's "merge keys". With merge keys, you can define base styles in one entry, then include those keys elsewhere. For example:

icon: &icon
  width: 50
  height: 50
icon_left
  <<: *icon
  x: 100
# The layout for icon_left will have the width/height from icon!

If you use both extends and Yaml merge keys, the Yaml merge keys are processed first, then extends. For clarity, however, you're probably just better off using extends exclusively.

Multiple layout files

Squib also supports the combination of multiple layout files. If you provide an Array of files then Squib will merge them sequentially. Colliding keys will be completely re-defined by the later file. Extends is processed after each file. Here's a complex example:

# load order: a.yml, b.yml

##############
# file a.yml #
##############
grandparent:
  x: 100
parent_a:
  extends: grandparent
  x: += 10   # evaluates to 110
parent_b:
  extends: grandparent
  x: += 20   # evaluates to 120

##############
# file b.yml #
##############
child_a:
  extends: parent_a  # i.e. extends a layout in a separate file
  x: += 3    # evaluates to 113 (i.e 110 + 3)
parent_b:    # redefined
  extends: grandparent
  x: += 30   # evaluates to 130 (i.e. 100 + 30)
child_b:
  extends: parent_b
  x: += 3    # evaluates to 133 (i.e. 130 + 3)

This can be helpful for:

• Creating a base layout for structure, and one for color (for easier color/black-and-white switching)
• Sharing base layouts with other designers

YAML merge keys are NOT supported across multiple files - use extends instead.

Built-in Layout Files

If your layout file is not found in the current directory, Squib will search for its own set of layout files (here's the latest the development version on GitHub. See the layouts.rb sample found here for some demonstrative examples.

Layout Sample

This sample demonstrates many different ways of using and combining layouts. This is the layouts.rb sample found here

{include:file:samples/layouts.rb}

Backends: Raster vs. Vector

Under the hood, Cairo has the ability to support a variety of surfaces to draw on, including both raster images stored in memory and vectors stored in SVG files. Thus, Squib supports the ability to handle both. They are options in the configuration file backend: memory or backend: svg.

If you save to a PDF then the backend will determine how your cards are saved too. For memory, the PDF will be filled with compressed raster images and be a larger file (yet it will still print at high quality... see discussion below). For SVG backends, PDFs will be smaller. If you have your deck backed by SVG, then the cards are auto-saved, so there is no save_svg in Squib. (Technically, the operations are stored and then flushed to the SVG file at the very end.)

There are trade-offs that one should consider here.

• Print quality is higher for raster images. This seems counterintuitive at first, but consider where Squib sits in your workflow. It's the final assembly line for your cards before they get printed. Cairo puts a ton of work into rendering each pixel perfectly when it works with raster images. Printers, on the other hand, don't think in vectors and will render your paths in their own memory with their own embedded libraries without putting a lot of work into antialiasing and various other graphical esoterica. You may notice that print-on-demand companies such as The Game Crafter only accept raster file types, because they don't want their customers complaining about printers not rendering vectors with enough care.
• PDFs are smaller for SVG back ends. If file size is a limitation for you, and it can be for some printers or internet forums, then an SVG back end for vectorized PDFs is the way to go.
• Squib is greedy with memory. While I've tested Squib with big decks on older computers, the memory backend is quite greedy with RAM. If memory is at a premium for you, switching to SVG might help.

Note: you can still load PNGs into an SVG-backed deck and load SVGs into a memory-backed deck. To me, the sweet spot is to keep all of my icons, text, and other stuff in vector form for infinite scaling and then render them all to pixels with Squib.

Fortunately, switching backends in Squib should be as trivial as changing the setting in the config file. So go ahead and experiment with both and see what works for you. See below for how the configuration options work.

Configuration File

Squib supports various configuration properties that can be specified in an external file. The config: option in Deck.new can specify an optional configuration file in YML format. The properties there are intended to be immutable for the life of the Deck. The options include:

• progress_bars (Boolean, default: false). When set to true, long-running operations will show a progress bar on the command line.
• hint (ColorString, default: off). Text hints are used to show the boundaries of text boxes. Can be enabled/disabled for individual commands, or set globally with the set command. This setting is overriden by set and individual commands.
• custom_colors (Hash of Colors, default: {}). Defines globally-available colors available to the deck that can be specified in commands.
• antialias (fast, good, best, none, gray, subpixel, default: best). Set the algorithm that Cairo will use for antialiasing. Using our benchmarks on large decks, best is only ~10% slower anyway. For more info see the Cairo docs.
• backend (svg or memory, default: memory). Defines how Cairo will store the operations. Memory is recommended for higher quality rendering.
• prefix (default: card_). When using an SVG backend, cards are auto-saved with this prefix and "%02d" numbering format.

For debugging/sanity purposes, if you want to make sure your configuration options are parsed correclty, the above options are also available as methods within Squib::Deck, for example:

Squib::Deck.new do
  puts backend # prints 'memory' by default
end

The following sample demonstrates the config file, found here

{include:file:samples/custom_config.rb}

Importing from Excel and CSV

Squib supports importing data from xlsx files and csv files. These methods are column-based, which means that they assume you have a header row in your table, and that header row will define the column. Squib will return a Hash of Arrays correspoding to each row. Warnings are thrown on things like duplicate columns. See the excel.rb and the csv_import.rb sample found here.

{include:file:samples/excel.rb}

Of course, you can always import your game data other ways using just Ruby. There's nothing special about Squib's methods other than their convenience.

Making Squib Verbose

By default, Squib's logger is set to WARN, but more fine-grained logging is embedded in the code. To set the logger, just put this at the top of your script:

Squib::logger.level = Logger::INFO

If you REALLY want to see tons of output, you can also set DEBUG, but that's not intended for general consumption.

Staying DRY

Squib tries to keep you DRY (Don't Repeat Yourself) with the following features:

• Custom layouts allow you to specify various arguments in a separate file. This is great for x-y coordinates and alignment properties that would otherwise clutter up perfectly readable code. Squib goes even further and has a special "extends" that works especially well for grouped-together styles.
• Flexible ranges and array handling: the range parameter in Squib is very flexible, meaning that one text command can specify different text in different fonts, styles, colors, etc. for each card. If you find yourself doing multiple text command for the same field across different ranges of cards, there's probably a better way to condense.
• Custom colors keep you from hardcoding magic color strings everywhere. Custom colors go into config.yml file.
• Plus, you know, Ruby.

Source control

You are using source control, right??

By default, Squib assumes Git. But it's not dogmatic about it. Tracking your progress, backing up, sharing data, topic branches, release management, and reverting into history are just some of the many, many useful things you can do with source control. For me, I tend to ignore any auto-generated files in my output folder, but version control everything else. I also try to keep my graphics vector files, so the files stay small. Version control is intended for source code, so large binary files that change often probably should not get checked in unless absolutely necessary. I tend to keep big raster graphics files (e.g. from Gimp) in cloud storage or elsewhere.

SublimeText

Using SublimeText? I like you already. I've written up some Squib snippets to ease remembering Squib commands. It's called Squib Snippets on Package Control. Compatible with SublimeText 3. Source code is also on Github (contributions welcome!). Check it out:

Decks with multiple orientations or sizes

If you want to make a deck that has some portrait and some landscape cards, I recommend you use multiple Squib::Decks. The pixel size of a given card is designed to not change thorughout the life of a Squib::Deck. To work with landscape cards, there is a rotate option on save_png so you can render your print-on-demand PNGs in portrait but keep everything else oriented toward landscape. The following example demonstrates how to do this, found here.

{include:file:samples/portrait-landscape.rb}

Rakefile

When you run squib new, you are given a basic Rakefile. At this stage of Squib, it's basically just a shortcut for ruby deck.rb. But, even in this simple form this Rakefile has some advantages:

• If you're in a subdirectory at the time, rake will simply traverse up and cd to the proper directory so you don't get rogue _output directories
• If you find yourself building multiple decks, you can make your own tasks for each one individually, or all (e.g. rake marketing)
• Don't need the require squib at the top of your code (although that breaks ruby deck.rb, so that's probably a bad idea)

Using Google Sheets

We don't officially support Google Sheets (yet), but this Gist might be helpful in automatically exporting the CSV.

Get Involved

Squib is an open source tool, and I welcome participation. Squib is currently in pre-release alpha, so the API is still maturing. I do change my mind about the names and meaning of things at this stage. I will document these changes as best as I can. I also highly recommend upgrading to new versions of Squib every chance you get (using Bundler).

Feel free to file a bug or feature request. For bugs, a minimal code example along with your OS and Ruby details would be ideal.

Testing Pre-Builds

If you want to test new features as I develop them, you can always point your Gemfile to the repository. Your Gemfile specification looks like this:

gem 'squib', git: 'git://github.com/andymeneely/squib', branch: 'dev'

• The dev branch is where I am working on features in-process. I have not done much regression testing at this point, but would love testing feedback nonetheless.
• The master branch is where I consider features and bug that are done and tested, but not released yet.

Contributing

If you want your code integrated:

1. Fork the git repository ( https://github.com/[my-github-username]/squib/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

Be sure to run the unit tests and packaging with just rake. Also, you can check that the samples render properly with rake sanity.

What's up the with the name?

Truthfully, I just thought it was a cool, simple word that was not used much in the Ruby community nor the board game community. But, now that I've committed to the name, I've realized that:

• Squibs are small explosive devices, much like Squib "explodes" your rules into a playable game
• Squibs are often used in heist movies, leading to a sudden plot twist that often resembles the twists of good tabletop game
• Squibs are also part of the Harry Potter world - they are people who are non-magical but wizard-born. Squib is aware of wizarding magic and comes from that heritage, but it's not magical itself.