Glimmer (The Original One And Only)

Glimmer is a cross-platform Ruby desktop development library. Glimmer's main innovation is a JRuby DSL that enables easy and efficient authoring of desktop application user-interfaces while relying on the robust platform-independent Eclipse SWT library. Glimmer additionally innovates by having built-in desktop UI data-binding support to greatly facilitate synchronizing the UI with domain models. As a result, that achieves true decoupling of object oriented components, enabling developers to solve business problems without worrying about UI concerns, or alternatively drive development UI-first, and then write clean business components test-first afterward.

You may learn more by reading this article: Eclipse Zone Tutorial

Examples

Hello World

Glimmer code (from samples/hello_world.rb):

include Glimmer

shell {
  text "Glimmer"
  label {
    text "Hello World!"
  }
}.open

Run:

glimmer samples/hello_world.rb

Glimmer app:

Tic Tac Toe

Glimmer code (from samples/tictactoe/tic_tac_toe.rb):

shell {
  text "Tic-Tac-Toe"
  composite {
    grid_layout 3, true
    (1..3).each { |row|
      (1..3).each { |column|
        button {
          layout_data :fill, :fill, true, true
          text        bind(@tic_tac_toe_board[row, column], :sign)
          enabled     bind(@tic_tac_toe_board[row, column], :empty)
          on_widget_selected {
            @tic_tac_toe_board.mark_box(row, column)
          }
        }
      }
    }
  }
}

Run:

glimmer samples/tictactoe/tic_tac_toe.rb

Glimmer app:

Resources

• Eclipse Zone Tutorial
• InfoQ Article
• RubyConf 2008 Video
• Code Blog

Background

Ruby is a dynamically-typed object-oriented language, which provides great productivity gains due to its powerful expressive syntax and dynamic nature. While it is proven by the Ruby on Rails framework for web development, it currently lacks a robust platform-independent framework for building desktop applications. Given that Java libraries can now be utilized in Ruby code through JRuby, Eclipse technologies, such as SWT, JFace, and RCP can help fill the gap of desktop application development with Ruby.

Platform Support

Glimmer runs on the following platforms:

• Mac
• Windows
• Linux

Pre-requisites

• Java SE Runtime Environment 7 or higher (find at https://www.oracle.com/java/technologies/javase-downloads.html)
• JRuby 9.2.10.0 (supporting Ruby 2.5.x syntax) (find at https://www.jruby.org/download)

On Mac and Linux, an easy way to obtain JRuby is through RVM by running:

rvm install jruby-9.2.10.0

Setup

Please follow these instructions to make the glimmer command available on your system.

Option 1: Direct Install

Run this command to install directly:

jgem install glimmer -v 0.4.3

Option 2: Bundler

Add the following to Gemfile:

gem 'glimmer', '~> 0.4.3'

And, then run:

bundle install

Glimmer command

Usage:

glimmer application.rb

Runs a Glimmer application using JRuby, automatically preloading the glimmer ruby gem and SWT jar dependency.

Example:

glimmer hello_world.rb

This runs the Glimmer application hello_world.rb

Glimmer DSL Syntax

Widgets

Glimmer UIs (user interfaces) are modeled with widgets (wrappers around the SWT library widgets found here: https://help.eclipse.org/2019-12/topic/org.eclipse.platform.doc.isv/guide/swt_widgets_controls.htm?cp=2_0_7_0_0).

In Glimmer DSL, widgets are declared with lowercase underscored naming (you may look at usage examples in the samples directory).

The shell widget is always the outermost widget containing all others in a desktop windowed application. It is centered upon initial display and has a minimum width of 130 (can be re-centered when needed with @shell.center method)

Other widget examples:

• button: wrapper for org.eclipse.swt.widgets.Button
• label: wrapper for org.eclipse.swt.widgets.Label
• tab_folder: wrapper for org.eclipse.swt.widgets.TabFolder
• tab_item: wrapper for org.eclipse.swt.widgets.TabItem
• table: wrapper for org.eclipse.swt.widgets.Table
• table_column: wrapper for org.eclipse.swt.widgets.TableColumn
• tree: wrapper for org.eclipse.swt.widgets.Tree

Widget Styles

SWT widgets receive SWT styles in their constructor as per this guide:

https://wiki.eclipse.org/SWT_Widget_Style_Bits

Glimmer DSL facilitates that by passing symbols representing SWT constants as widget method arguments (i.e. inside widget () parentheses. See example below) in lower case version (e.g. SWT::MULTI becomes :multi).

These styles customize widget look, feel, and behavior.

Example:

list(:multi) { # SWT styles go inside ()
  # ...
}

Passing :multi to list widget enables list element multi-selection.

composite(:border) { # SWT styles go inside ()
  # ...
}

Passing :border to composite widget ensures it has a border.

When you need to pass in multiple SWT styles, simply separate by commas.

Example:

text(:center, :border) { # Multiple SWT styles separated by comma
  # ...
}

Glimmer ships with SWT style smart defaults so you wouldn't have to set them yourself most of the time (albeit you can always override them):

• text(:border)
• table(:border)
• spinner(:border)
• list(:border, :v_scroll)
• button(:push)

You may check out all available SWT styles here:

https://help.eclipse.org/2019-12/nftopic/org.eclipse.platform.doc.isv/reference/api/org/eclipse/swt/SWT.html

Note (advanced case outside of standard Glimmer DSL):

When building a widget-related SWT object manually (e.g. GridData.new(...)), you are expected to use SWT::CONSTANT directly or BIT-OR a few SWT constants together like SWT::BORDER | SWT::V_SCROLL.

Glimmer facilitates that with GSWT class by allowing you to pass multiple styles as an argument array of symbols instead of dealing with BIT-OR. For example: GSWT[:border, :v_scroll]

Non-resizable Window

SWT Shell widget by default is resizable. To make it non-resizable, one must pass a complicated style bit concoction like GSWT[:shell_trim] & (~GSWT[:resize]) & (~GSWT[:max]).

Glimmer makes this easier by alternatively offering :no_resize extra SWT style, added for convenience. This makes declaring an non-resizable window as easy as:

shell(:no_resize) {
  # ...
}

Widget Properties

Widget properties such as value, enablement, and layout details are set within the widget block using methods matching SWT widget property names in lower snakecase. You may refer to SWT widget guide for details on available widget properties:

https://help.eclipse.org/2019-12/topic/org.eclipse.platform.doc.isv/guide/swt_widgets_controls.htm?cp=2_0_7_0_0

Code examples:

label {
  text "Hello World!" # SWT properties go inside {} block
}

In the above example, the label widget text property was set to "Hello World!".

button {
  enabled bind(@tic_tac_toe_board.box(row, column), :empty)
}

In the above example, the text widget enabled property was data-bound to #empty method on @tic_tac_toe_board.box(row, column) (learn more about data-binding below)

Layouts

Glimmer lays widgets out visually using SWT layouts, which can only be set on composite widget and subclasses.

The most common SWT layouts are:

• FillLayout: lays widgets out in equal proportion horizontally or vertically with spacing/margin options. This is the default layout for shell (with :horizontal option) in Glimmer.
• RowLayout: lays widgets out horizontally or vertically in varying proportions with advanced spacing/margin/justify options
• GridLayout: lays widgets out in a grid with advanced spacing/margin/alignment/indentation options. This is the default layout for composite in Glimmer. It is important to master.

In Glimmer DSL, just like widgets, layouts can be specified with lowercase underscored names followed by a block containing properties, also lowercase underscored names (e.g. RowLayout is row_layout).

Example:

composite {
  row_layout {
    wrap true
    pack false
    justify true
    type :vertical
    margin_left 1
    margin_top 2
    margin_right 3
    margin_bottom 4
    spacing 5
  }
  # ... widgets follow
}

Alternatively, a layout may be constructed by following the SWT API for the layout object. For example, a RowLayout can be constructed by passing it an SWT style constant (Glimmer automatically accepts symbols (e.g. :horizontal) for SWT style arguments like SWT::HORIZONTAL.)

composite {
  row_layout :horizontal
  # ... widgets follow
}

Here is a more sophisticated example taken from hello_computed.rb sample:

shell {
  text "Hello Computed"
  composite {
    grid_layout {
      num_columns 2
      make_columns_equal_width true
      horizontal_spacing 20
      vertical_spacing 10
    }
    label {text "First &Name: "}
    text {
      text bind(@contact, :first_name)
      layout_data {
        horizontalAlignment :fill
        grabExcessHorizontalSpace true
      }
    }
    label {text "&Last Name: "}
    text {
      text bind(@contact, :last_name)
      layout_data {
        horizontalAlignment :fill
        grabExcessHorizontalSpace true
      }
    }
    label {text "&Year of Birth: "}
    text {
      text bind(@contact, :year_of_birth)
      layout_data {
        horizontalAlignment :fill
        grabExcessHorizontalSpace true
      }
    }
    label {text "Name: "}
    label {
      text bind(@contact, :name, computed_by: [:first_name, :last_name])
      layout_data {
        horizontalAlignment :fill
        grabExcessHorizontalSpace true
      }
    }
    label {text "Age: "}
    label {
      text bind(@contact, :age, :fixnum, computed_by: [:year_of_birth])
      layout_data {
        horizontalAlignment :fill
        grabExcessHorizontalSpace true
      }
    }
  }
}.open

Check out the samples directory for more advanced examples of layouts in Glimmer.

Defaults:

Glimmer composites always come with grid_layout by default, but you can still specify explicitly if you'd like to set specific properties on it.

Glimmer shell always comes containing one composite by default that wraps around specified shell content. That specific composite (the one directly under shell) has fill_layout with :horizontal type.

This is a great guide for learning more about SWT layouts:

https://www.eclipse.org/articles/Article-Understanding-Layouts/Understanding-Layouts.htm

Also, for a reference, check the SWT API:

https://help.eclipse.org/2019-12/nftopic/org.eclipse.platform.doc.isv/reference/api/index.html

Layout Data

Layouts organize widgets following common rules for all widgets directly under a composite. But, what if a specific widget needs its own rules. That's where layout data comes into play.

By convention, SWT layouts expect widgets to set layout data with a class matching their class name with the word "Data" replacing "Layout":

• GridLayout on a composite demands GridData on contained widgets
• RowLayout on a composite demands RowData on contained widgets

Not all layouts support layout data to further customize widget layouts. For example, FillLayout supports no layout data.

Unlike widgets and layouts in Glimmer DSL, layout data is simply specified with layout_data keyword nested inside a widget block body, and followed by arguments and/or a block of its own properties (lowercase underscored names).

Glimmer automatically deduces layout data class name by convention as per rule above, with the assumption that the layout data class lives under the same exact Java package as the layout (one can set custom layout data that breaks convention if needed in rare cases. See code below for an example)

Glimmer also automatically accepts symbols (e.g. :fill) for SWT style arguments like SWT::FILL.

Examples:

composite {
  row_layout :horizontal
  label {
    layout_data { # followed by properties
      width 50
      height 30
    }
  }
  # ... more widgets follow
}

composite {
  grid_layout 3, false # grid layout with 3 columns not of equal width
  label {
    # layout data followed by arguments passed to SWT GridData constructor
    layout_data :fill, :end, true, false
  }
}

composite {
  grid_layout 3, false # grid layout with 3 columns not of equal width
  label {
    # layout data set explicitly via an object (helps in rare cases that break convention)
    layout_data GridData.new(GSWT[:fill], GSWT[:end], true, false)
  }
}

NOTE: Layout data must never be reused between widgets. Always specify or clone again for every widget.

This is a great guide for learning more about SWT layouts:

https://www.eclipse.org/articles/Article-Understanding-Layouts/Understanding-Layouts.htm

Also, for a reference, check the SWT API:

https://help.eclipse.org/2019-12/nftopic/org.eclipse.platform.doc.isv/reference/api/index.html

Colors

Colors make up a subset of widget properties. SWT accepts color objects created with RGB (Red Green Blue) or RGBA (Red Green Blue Alpha). Glimmer supports constructing color objects using the rgb and rgba DSL methods.

Example:

label {
  background rgb(144, 240, 244)
  foreground rgba(38, 92, 232, 255)
}

SWT also supports standard colors available as constants under the SWT namespace with the COLOR_ prefix (e.g. SWT::COLOR_BLUE, SWT::COLOR_WHITE, SWT::COLOR_RED)

Glimmer accepts these constants as lowercase Ruby symbols with or without color_ prefix.

Example:

label {
  background :black
  foreground :yellow
}
label {
  background :color_white
  foreground :color_red
}

You may check out all available standard colors in SWT over here (having COLOR_ prefix):

https://help.eclipse.org/2019-12/nftopic/org.eclipse.platform.doc.isv/reference/api/org/eclipse/swt/SWT.html

Fonts

Fonts are represented in Glimmer as a hash of name, height, and style keys.

The style can be one (or more) of 3 values: :normal, :bold, and :italic

Example:

label {
  font name: 'Arial', height: 36, style: :normal
}

Keys are optional, so some of them may be left off. When passing multiple styles, they are included in an array.

Example:

label {
  font style: [:bold, :italic]
}

Data-Binding

Data-binding is done with bind command following widget property to bind and taking model and bindable attribute as arguments.

Data-binding examples:

• text bind(contact, :first_name)
• text bind(contact, 'address.street')
• text bind(contact, 'addresses[1].street')
• text bind(contact, :age, computed_by: :date_of_birth)
• text bind(contact, :name, computed_by: [:first_name, :last_name])
• text bind(contact, 'profiles[0].name', computed_by: ['profiles[0].first_name', 'profiles[0].last_name'])

The 1st example binds the text property of a widget like label to the first name of a contact model.

The 2nd example binds the text property of a widget like label to the nested street of the address of a contact. This is called nested property data binding.

The 3rd example binds the text property of a widget like label to the nested indexed address street of a contact. This is called nested indexed property data binding.

The 4th example demonstrates computed value data binding whereby the value of age depends on changes to date_of_birth.

The 5th example demonstrates computed value data binding whereby the value of name depends on changes to both first_name and last_name.

The 6th example demonstrates nested indexed computed value data binding whereby the value of profiles[0].name depends on changes to both nested profiles[0].first_name and profiles[0].last_name.

You may learn more about Glimmer's syntax by reading the Eclipse Zone Tutorial mentioned in resources and opening up the samples under the samples directory.

Observer

Glimmer comes with Observer module, which is used internally for data-binding, but can also be used externally for custom use of the Observer Pattern.

In summary, the class that needs to observe an object, must include Observer and implement #call(new_value) method. The class to be observed doesn't need to do anything. It will automatically be enhanced by Glimmer for observation.

To register observer, one has to call the #observe method and pass in the observable and the property(ies) to observe.

class TicTacToe
  include Glimmer
  include Observer

  def initialize
    # ...
    observe(@tic_tac_toe_board, :game_status)
  end

  def call(game_status)
    display_win_message if game_status == TicTacToeBoard::WIN
    display_draw_message if game_status == TicTacToeBoard::DRAW
  end
  # ...
end

Alternatively, one can use a default Observer::Proc implementation via Observer.proc method:

observer = Observer.proc { |new_value| puts new_value }
observer.observe(@tic_tac_toe_board, :game_status)

Observers can be a good mechanism for displaying dialog messages with Glimmer (using SWT's MessageBox).

Look at samples/tictactoe/tic_tac_toe.rb for an Observer dialog message example (sample below).

class TicTacToe
  include Glimmer
  include Observer

  def initialize
    # ...
    observe(@tic_tac_toe_board, :game_status)
  end

  def call(game_status)
    display_win_message if game_status == TicTacToeBoard::WIN
    display_draw_message if game_status == TicTacToeBoard::DRAW
  end

  def display_win_message
    display_game_over_message("Player #{@tic_tac_toe_board.winning_sign} has won!")
  end

  def display_draw_message
    display_game_over_message("Draw!")
  end

  def display_game_over_message(message)
    message_box = MessageBox.new(@shell.widget)
    message_box.setText("Game Over")
    message_box.setMessage(message)
    message_box.open
    @tic_tac_toe_board.reset
  end
  # ...
end

Samples

Check the samples directory for examples on how to write Glimmer applications. To run a sample, make sure to install the glimmer gem first and then use the glimmer command to run it (alternatively, you may clone the repo, follow CONTRIBUTING.md instructions, and run samples locally with development glimmer command: bin/glimmer --dev).

Examples:

glimmer samples/hello_tab.rb
glimmer samples/hello_combo.rb
glimmer samples/hello_list_single_selection.rb
glimmer samples/hello_list_multi_selection.rb
glimmer samples/contactmanager/contact_manager.rb

The last example (contact_manager.rb) is a good sample about how to build tables with Glimmer including data-binding, filtering, and sorting. It even comes with specs in spec/samples/contactmanager/contact_manager_presenter_spec.rb to demonstrate how Glimmer facilitates TDD (test-driven development) with the Model View Presenter pattern (a variation on MVC) by separating testable presentation logic from the view layer with data-binding.

For a more elaborate project built with Glimmer, check out this educational game:

Math Bowling

SWT Reference

https://www.eclipse.org/swt/docs.php

Here is the SWT API:

https://help.eclipse.org/2019-12/nftopic/org.eclipse.platform.doc.isv/reference/api/index.html

Here is a list of SWT widgets:

https://help.eclipse.org/2019-12/topic/org.eclipse.platform.doc.isv/guide/swt_widgets_controls.htm?cp=2_0_7_0_0

Here is a list of SWT style bits:

https://wiki.eclipse.org/SWT_Widget_Style_Bits

SWT Packages

Glimmer automatically imports all SWT Java packages upon adding include Glimmer to a class or module.

Still, if you'd like to import manually elsewhere, you may add the following lines to your code (in the class or module body) to import SWT Java packages using include_package:

include_package 'org.eclipse.swt'
include_package 'org.eclipse.swt.widgets'
include_package 'org.eclipse.swt.layout'
include_package 'org.eclipse.swt.graphics'

To import a specific SWT Java class using java_import, add the following:

java_import 'org.eclipse.swt.SWT'

This allows you to call SWT Java classes from Ruby without mentioning package namespaces.

For example, after imports, org.eclipse.swt.graphics.Color can be referenced by just Color

Girb (Glimmer irb)

With Glimmer installed, you may run want to run girb instead of standard irb to have SWT preloaded and the Glimmer library required and included for quick Glimmer coding/testing.

Logging

Glimmer comes with a Ruby Logger accessible via Glimmer.logger Its level of logging defaults to Logger::WARN It may be configured to show a different level of logging as follows:

Glimmer.logger.level = Logger::DEBUG

This results in more verbose debugging log to STDOUT, which is helpful in troubleshooting Glimmer DSL syntax when needed.

Example log:

D, [2017-07-21T19:23:12.587870 #35707] DEBUG -- : method: shell and args: []
D, [2017-07-21T19:23:12.594405 #35707] DEBUG -- : ShellCommandHandler will handle command: shell with arguments []
D, [2017-07-21T19:23:12.844775 #35707] DEBUG -- : method: composite and args: []
D, [2017-07-21T19:23:12.845388 #35707] DEBUG -- : parent is a widget: true
D, [2017-07-21T19:23:12.845833 #35707] DEBUG -- : on listener?: false
D, [2017-07-21T19:23:12.864395 #35707] DEBUG -- : WidgetCommandHandler will handle command: composite with arguments []
D, [2017-07-21T19:23:12.864893 #35707] DEBUG -- : widget styles are: []
D, [2017-07-21T19:23:12.874296 #35707] DEBUG -- : method: list and args: [:multi]
D, [2017-07-21T19:23:12.874969 #35707] DEBUG -- : parent is a widget: true
D, [2017-07-21T19:23:12.875452 #35707] DEBUG -- : on listener?: false
D, [2017-07-21T19:23:12.878434 #35707] DEBUG -- : WidgetCommandHandler will handle command: list with arguments [:multi]
D, [2017-07-21T19:23:12.878798 #35707] DEBUG -- : widget styles are: [:multi]

Raw JRuby Command

If there is a need to run Glimmer directly via the jruby command, you may run the following:

jruby -J-classpath "path_to/swt.jar" -r glimmer -S application.rb

The -J-classpath option specifies the swt.jar file path, which can be a manually downloaded version of SWT, or otherwise the one included in the gem. You can lookup the one included in the gem by running jgem which glimmer to find the gem path and then look through the vendor directory.

The -r option preloads (requires) the glimmer library in Ruby.

The -S option specifies a script to run.

Mac Support

Mac is well supported with the glimmer command. However, if there is a reason to use the raw jruby command, you need to pass an extra option (-J-XstartOnFirstThread) to JRuby on the Mac.

Example:

jruby -J-XstartOnFirstThread -J-classpath "path_to/swt.jar" -r glimmer -S application.rb

Feature Suggestions

These features have been suggested. You might see them in a future version of Glimmer. You are welcome to contribute more feature suggestions.

TODO.md

Change Log

CHANGELOG.md

Contributing

CONTRIBUTING.md

Contributors

• Andy Maleh (Founder)
• Dennis Theisen

License

Copyright (c) 2007-2020 Andy Maleh. See LICENSE.txt for further details.