Glimmer 0.8.0 Beta (Ruby Desktop Development GUI Library)

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


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Examples

Hello, World!

Glimmer code (from samples/hello/hello_world.rb):

include Glimmer

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

Run:

glimmer samples/hello/hello_world.rb

Glimmer app:

Hello World

Tic Tac Toe

Glimmer code (from samples/elaborate/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(row, column)
          }
        }
      }
    }
  }
}
# ...

Run:

glimmer samples/elaborate/tic_tac_toe.rb

Glimmer app:

Tic Tac Toe

NOTE: Glimmer is in beta mode. Please help make better by adopting for small or low risk projects and providing feedback.

Table of Contents

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

Glimmer's GUI has the native look and feel of each operating system it runs on since it uses SWT behind the scenes, which leverages the following native libraries:

  • Win32 on Windows
  • Cocoa on Mac
  • GTK on Linux

More info about the SWT GUI on various platforms can be found on the Eclipse WIKI and SWT FAQ:

https://wiki.eclipse.org/SWT/Devel/Gtk/Dev_guide#Win32.2FCocoa.2FGTK https://www.eclipse.org/swt/faq.php

Pre-requisites

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

rvm install jruby-9.2.11.1

Glimmer might still work on lower versions of Java, JRuby and SWT, but there are no guarantees, so it is best to stick to the pre-requisites outlined above.

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 0.8.0

jgem is JRuby's version of gem command. RVM allows running gem as an alias. Otherwise, you may also run jruby -S gem install ...

Option 2: Bundler

Add the following to Gemfile:

gem 'glimmer', '~> 0.8.0'

And, then run:

jruby -S bundle install

Glimmer Command

Basic Usage

glimmer application.rb

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

Example:

glimmer samples/hello/hello_world.rb

This runs the Glimmer "Hello, World!" sample.

If you cloned this project locally, you may run bin/glimmer instead.

Example:

bin/glimmer samples/hello/hello_world.rb

Advanced Usage

Below are the full usage instructions that come up when running glimmer without args.

Usage: glimmer [--quiet] [--debug] [--log-level=VALUE] [[ENV_VAR=VALUE]...] [[-jruby-option]...] (application.rb or task[task_args]) [[application2.rb]...]

Runs Glimmer applications/tasks.

Either a single task or one or more applications may be specified.

When a task is specified, it runs via rake. Some tasks take arguments in square brackets.

Available tasks are below (you may also lookup by adding `require 'glimmer/rake_task'` in Rakefile and running rake -T):
glimmer package                                                   # Package app for distribution (generating config, jar, and native files)
glimmer package:config                                            # Generate JAR config file
glimmer package:jar                                               # Generate JAR file
glimmer package:native                                            # Generate Native files (DMG/PKG/APP on the Mac)
glimmer scaffold[app_name]                                        # Scaffold a Glimmer application directory structure to begin building a new app
glimmer scaffold:custom_shell[custom_shell_name,namespace]        # Scaffold a Glimmer::UI::CustomShell subclass (represents a full window view) under app/views (namespace is optional)
glimmer scaffold:custom_shell_gem[custom_shell_name,namespace]    # Scaffold a Glimmer::UI::CustomShell subclass (represents a full window view) under its own Ruby gem + app project (namespace is required)
glimmer scaffold:custom_widget[custom_widget_name,namespace]      # Scaffold a Glimmer::UI::CustomWidget subclass (represents a part of a view) under app/views (namespace is optional)
glimmer scaffold:custom_widget_gem[custom_widget_name,namespace]  # Scaffold a Glimmer::UI::CustomWidget subclass (represents a part of a view) under its own Ruby gem project (namespace is required)

When applications are specified, they are run using JRuby, 
automatically preloading the glimmer Ruby gem and SWT jar dependency.

Optionally, extra Glimmer options, JRuby options and environment variables may be passed in.

Glimmer options:
- "--quiet"           : Does not announce file path of Glimmer application being launched
- "--debug"           : Displays extra debugging information, passes "--debug" to JRuby, and enables debug logging
- "--log-level=VALUE" : Sets Glimmer's Ruby logger level ("ERROR" / "WARN" / "INFO" / "DEBUG"; default is none)

Example: glimmer samples/hello_world.rb

This runs the Glimmer application samples/hello_world.rb

Example (Glimmer/JRuby option specified):

glimmer --debug samples/hello/hello_world.rb

Runs Glimmer application with JRuby debug option to enable JRuby debugging.

Example (Multiple apps):

glimmer samples/hello/hello_world.rb samples/hello_tab.rb

Launches samples/hello/hello_world.rb and samples/hello_tab.rb at the same time, each in a separate JRuby thread.

Scaffolding

Glimmer borrows from Rails the idea of Scaffolding, that is generating a structure for your app files that helps you get started just like true building scaffolding helps construction workers, civil engineers, and architects.

Glimmer scaffolding goes beyond just scaffolding the app files that Rails does. It also packages it and launches it, getting you to a running and delivered state of an advanced "Hello, World!" Glimmer application right off the bat.

This should greatly facilitate building a new Glimmer app by helping you be productive and focus on app details while letting Glimmer scaffolding take care of initial app file structure concerns, such as adding:

  • Main application class that includes Glimmer
  • Main application view that houses main window content, about dialog, and preferences dialog
  • View and Model directories
  • Rakefile including Glimmer tasks
  • Version
  • License
  • Icon
  • Bin file for starting application

NOTE: Scaffolding requires RVM and currently supports Mac packaging only at the moment.

App

Before you start, make sure you are in a JRuby environment with Glimmer gem installed as per "Direct Install" pre-requisites.

To scaffold a Glimmer app from scratch, run the following command:

glimmer scaffold[AppName]

This will generate an advanced "Hello, World!" app, package it as a Mac native file (DMG/PKG/APP), and launch it all in one fell swoop.

Suppose you run:

glimmer scaffold[CarMaker]

You should see output like the following:

Created CarMaker/.ruby-version
Created CarMaker/.ruby-gemset
Created CarMaker/VERSION
Created CarMaker/LICENSE.txt
Created CarMaker/Gemfile
Created CarMaker/Rakefile
Created CarMaker/app/car_maker.rb
Created CarMaker/app/views/car_maker/app_view.rb
Created CarMaker/package/macosx/Car Maker.icns
Created CarMaker/bin/car_maker
...

Eventually, it will launch an advanced "Hello, World!" app window having the title of your application and a Mac icon.

Glimmer Scaffold App

Custom Shell

To scaffold a Glimmer custom shell (full window view) for an existing Glimmer app, run the following command:

glimmer scaffold:custom_shell[custom_shell_name]

Custom Widget

To scaffold a Glimmer custom widget (part of a view) for an existing Glimmer app, run the following command:

glimmer scaffold:custom_widget[custom_widget_name]

Custom Shell Gem

Custom shell gems are self-contained Glimmer apps as well as reusable custom shells. They have everything scaffolded Glimmer apps come with in addition to gem content like a Jeweler Rakefile that can build gemspec and release gems. Unlike scaffolded Glimmer apps, custom shell gem content lives under the lib directory (not app). They can be packaged as both a native executable (e.g. Mac DMG/PKG/APP) and a Ruby gem. Of course, you can just build a Ruby gem and disregard native executable packaging if you do not need it.

To scaffold a Glimmer custom shell gem (full window view distributed as a Ruby gem), run the following command:

glimmer scaffold:custom_shell_gem[custom_shell_name, namespace]

It is important to specify a namespace to avoid having your gem clash with existing gems.

The Ruby gem name will follow the convention "glimmer-cs-customwidgetname-namespace" (the 'cs' is for Custom Shell).

Only official Glimmer gems created by the Glimmer project committers will have no namespace (e.g. glimmer-cs-gladiator Ruby gem)

Examples:

Custom Widget Gem

To scaffold a Glimmer custom widget gem (part of a view distributed as a Ruby gem), run the following command:

glimmer scaffold:custom_widget_gem[custom_widget_name, namespace]

It is important to specify a namespace to avoid having your gem clash with existing gems.

The Ruby gem name will follow the convention "glimmer-cw-customwidgetname-namespace" (the 'cw' is for Custom Widget)

Only official Glimmer gems created by the Glimmer project committers will have no namespace (e.g. glimmer-cw-video Ruby gem)

Example: https://github.com/AndyObtiva/glimmer-cw-video

Girb (Glimmer irb) Command

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

girb

If you cloned this project locally, you may run bin/girb instead.

bin/girb

Watch out for hands-on examples in this README indicated by "you may copy/paste in girb"

Glimmer DSL Syntax

Glimmer DSL syntax consists of static keywords and dynamic keywords to build and bind user-interface objects.

Static keywords are pre-identified keywords in the Glimmer DSL, such as shell, rgb, and bind.

Dynamic keywords are dynamically figured out from available SWT widgets, custom widgets, and properties. Examples are: label, combo, and text.

The only reason to distinguish between both types of Glimmer DSL keywords is to realize that importing new Java SWT custom widget libraries and Ruby custom widgets automatically expands Glimmer's available DSL syntax via new dynamic keywords.

For example, if a project adds this custom SWT library:

https://www.eclipse.org/nebula/widgets/cdatetime/cdatetime.php?page=operation

Glimmer will automatically support using the keyword c_date_time

You will learn more about widgets next.

Widgets

Glimmer GUIs (user interfaces) are modeled with widgets, which are wrappers around the SWT library widgets found here:

https://www.eclipse.org/swt/widgets/

This screenshot taken from the link above should give a glimpse of how SWT widgets look and feel:

SWT Widgets

In Glimmer DSL, widgets are declared with lowercase underscored names mirroring their SWT names minus the package name:

  • shell instantiates org.eclipse.swt.widgets.Shell
  • text instantiates org.eclipse.swt.widgets.Text
  • button instantiates org.eclipse.swt.widgets.Button
  • label instantiates org.eclipse.swt.widgets.Label
  • composite instantiates org.eclipse.swt.widgets.Composite
  • tab_folder instantiates org.eclipse.swt.widgets.TabFolder
  • tab_item instantiates org.eclipse.swt.widgets.TabItem
  • table instantiates org.eclipse.swt.widgets.Table
  • table_column instantiates org.eclipse.swt.widgets.TableColumn
  • tree instantiates org.eclipse.swt.widgets.Tree
  • combo instantiates org.eclipse.swt.widgets.Combo
  • list instantiates org.eclipse.swt.widgets.List

Every widget is sufficiently declared by name, but may optionally be accompanied with:

  • SWT style argument wrapped by parenthesis according to Glimmer Style Guide (see next section for details).
  • Ruby block containing properties (widget attributes) and content (nested widgets)

For example, if we were to revisit samples/hello/hello_world.rb above (you may copy/paste in girb):

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

Note that shell instantiates the outer shell widget, in other words, the window that houses all of the desktop graphical user interface.

shell is then followed by a block that contains

# ...
  text "Glimmer" # text property of shell
  label { # label widget declaration as content of shell
    text "Hello, World!" # text property of label
  }
# ...

The first line declares a property called text, which sets the title of the shell (window) to "Glimmer". Properties always have arguments (not wrapped by parenthesis according to Glimmer Style Guide), such as the text "Glimmer" in this case, and do NOT have a block (this distinguishes them from widget declarations).

The second line declares the label widget, which is followed by a Ruby content block that contains its text property with value "Hello, World!"

The widget block may optionally receive an argument representing the widget proxy object that the block content is for. This is useful in rare cases when the content code needs to refer to parent widget during declaration. You may leave that argument out most of the time and only add when absolutely needed.

Example:

shell {|shell_proxy|
  #...
}

Remember that The shell widget is always the outermost widget containing all others in a Glimmer desktop windowed application.

After it is declared, a shell must be opened with the #open method, which can be called on the block directly as in the example above, or by capturing shell in a @shell variable (shown in example below), and calling #open on it independently (recommended in actual apps)

@shell = shell {
  # properties and content
  # ...
}
@shell.open

It is centered upon initial display and has a minimum width of 130 (can be re-centered when needed with @shell.center method after capturing shell in a @shell variable as per samples)

Check out the samples directory for more examples.

Example from hello_tab.rb sample (you may copy/paste in girb):

Hello Tab 1

Hello Tab 2

shell {
  text "SWT"
  tab_folder {
    tab_item {
      text "Tab 1"
      label {
        text "Hello, World!"
      }
    }
    tab_item {
      text "Tab 2"
      label {
        text "Bonjour Univers!"
      }
    }
  }
}.open

Display

SWT Display is a singleton in Glimmer. It is used in SWT to represent your display device, allowing you to manage GUI globally and access available monitors. It is automatically instantiated upon first instantiation of a shell widget. Alternatively, for advanced use cases, it can be created explicitly with Glimmer display keyword. When a shell is later declared, it automatically uses the display created earlier without having to explicitly hook it.

@display = display {
  cursor_location 300, 300
  on_event_keydown {
    # ...
  }
  # ...
}
@shell = shell { # uses display created above
}

The benefit of instantiating an SWT Display explicitly is to set Properties or Observers. Although SWT Display is not technically a widget, it has similar APIs in SWT and similar DSL support in Glimmer.

SWT Proxies

Glimmer follows Proxy Design Pattern by having Ruby proxy wrappers for all SWT objects:

  • Glimmer::SWT:WidgetProxy wraps all descendants of org.eclipse.swt.widgets.Widget except the ones that have their own wrappers.
  • Glimmer::SWT::ShellProxy wraps org.eclipse.swt.widgets.Shell
  • Glimmer::SWT:TabItemProxy wraps org.eclipse.swt.widget.TabItem (also adds a composite to enable adding content under tab items directly in Glimmer)
  • Glimmer::SWT:LayoutProxy wraps all descendants of org.eclipse.swt.widget.Layout
  • Glimmer::SWT:LayoutDataProxy wraps all layout data objects
  • Glimmer::SWT:DisplayProxy wraps org.eclipse.swt.widget.Display (manages displaying GUI)
  • Glimmer::SWT:ColorProxy wraps org.eclipse.swt.graphics.Color
  • Glimmer::SWT:FontProxy wraps org.eclipse.swt.graphics.Font
  • Glimmer::SWT::WidgetListenerProxy wraps all widget listeners

These proxy objects have an API and provide some convenience methods, some of which are mentioned below.

#content { ... }

Glimmer allows re-opening any widget and adding properties or extra content after it has been constructed already by using the #content method.

Example (you may copy/paste in girb):

@shell = shell {
  text "Application"
  row_layout
  @label1 = label {
    text "Hello,"
  }
}
@shell.content {
  minimum_size 130, 130
  label {
    text "World!"
  }
}
@label1.content {
  foreground :red
}
@shell.open
#swt_widget

Glimmer widget objects come with an instance method #swt_widget that returns the actual SWT Widget object wrapped by the Glimmer widget object. It is useful in cases you'd like to do some custom SWT programming outside of Glimmer.

Example (you may copy/paste in girb):

@shell = shell {
  button {
    text "Press Me"
    on_widget_selected {
      message_box = MessageBox.new(@shell.swt_widget) # passing SWT Shell widget
      message_box.setText("Surprise")
      message_box.setMessage("You have won $1,000,000!")
      message_box.open      
    }
  }
}
@shell.open
Shell widget proxy methods

Shell widget proxy has extra methods specific to SWT Shell:

  • #open: Opens the shell, making it visible and active, and starting the SWT Event Loop (you may learn more about it here: https://help.eclipse.org/2019-12/nftopic/org.eclipse.platform.doc.isv/reference/api/org/eclipse/swt/widgets/Display.html). If shell was already open, but hidden, it makes the shell visible.
  • #show: Alias for #open
  • #hide: Hides a shell setting "visible" property to false
  • #close: Closes the shell
  • #center: Centers the shell within monitor it is in
  • #start_event_loop: (happens as part of #open) Starts SWT Event Loop (you may learn more about it here: https://help.eclipse.org/2019-12/nftopic/org.eclipse.platform.doc.isv/reference/api/org/eclipse/swt/widgets/Display.html). This method is not needed except in rare circumstances where there is a need to start the SWT Event Loop before opening the shell.
  • #visible?: Returns whether a shell is visible
  • #opened_before?: Returns whether a shell has been opened at least once before (additionally implying the SWT Event Loop has been started already)
  • #visible=: Setting to true opens/shows shell. Setting to false hides the shell.
  • #pack: Packs contained widgets using SWT's Shell#pack method
  • #pack_same_size: Packs contained widgets without changing shell's size when widget sizes change

Dialog

Dialog is a variation on Shell. It is basically a shell that is modal (blocks what's behind it) and belongs to another shell. It only has a close button.

Glimmer facilitates building dialogs by using the dialog keyword, which automatically adds the SWT.DIALOG_TRIM and SWT.APPLICATION_MODAL widget styles needed for a dialog.

Glimmer DSL provides support for SWT Menu and MenuItem widgets.

There are 2 main types of menus in SWT:

  • Menu Bar (shows up on top)
  • Pop Up Menu (shows up when right-clicking a widget)

Underneath both types, there can be a 3rd menu type called Drop Down.

Glimmer provides special support for Drop Down menus as it automatically instantiates associated Cascade menu items and wires together with proper parenting, swt styles, and calling setMenu.

The ampersand symbol indicates the keyboard shortcut key for the menu item (e.g. '&Help' can be triggered on Windows by hitting ALT+H)

Example Menu Bar:

shell {
  menu_bar {
    menu {
      text "&File"
      menu_item {
        text "E&xit"
      }
      menu_item(0) {
        text "&New"
      }
      menu(1) {
        text "&Options"
        menu_item(:radio) {
          text "Option 1"
        }
        menu_item(:separator)
        menu_item(:check) {
          text "Option 3"
        }
      }
    }
    menu {
      text "&History"
      menu {
        text "&Recent"
        menu_item {
          text "File 1"
        }
        menu_item {
          text "File 2"
        }
      }
    }
  }
}.open

Example Pop Up Menu:

shell {
  label {
    text 'Right-Click Me'
    menu {
      menu {
        text '&History'
        menu {
          text "&Recent"
          menu_item {
            text "File 1"
          }
          menu_item {
            text "File 2"
          }
        }
      }
    }
  }
}.open

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 according to Glimmer Style Guide. 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)
  • tree(:border, :virtual, :v_scroll, :h_scroll)
  • 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

Explicit SWT Style Bit

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 swt keyword by allowing you to pass multiple styles as an argument array of symbols instead of dealing with BIT-OR. Example: 

style = swt(:border, :v_scroll)

Negative SWT Style Bits

In rare occasions, you might need to apply & with a negative (not) style bit to negate it from another style bit that includes it. Glimmer facilitates that by declaring the negative style bit via postfixing a symbol with !.

Example:

style = swt(:shell_trim, :max!) # creates a shell trim style without the maximize button (negated)

Extra SWT Styles

Non-resizable Window

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

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

shell(:no_resize) {
  # ...
}

Widget Properties

Widget properties such as text value, enablement, visibility, 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)

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 keywords.

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)

Glimmer supports constructing colors for these constants as lowercase Ruby symbols (with or without color_ prefix) passed to color DSL keyword

Example:

# ...
label {
  background color(:black)
  foreground color(:yellow)
}
label {
  background color(:color_white)
  foreground color(: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

#swt_color

Glimmer color objects come with an instance method #swt_color that returns the actual SWT Color object wrapped by the Glimmer color object. It is useful in cases you'd like to do some custom SWT programming outside of Glimmer.

Example:

color(:black).swt_color # returns SWT Color object

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]
}
# ...

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
}
# ...

If you data-bind any layout properties, when they change, the shell containing their widget re-packs its children (calls #pack method automatically) to ensure proper relayout of all widgets.

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, on_write: :to_i, 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 with fill_layout having :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(swt(:fill), swt(:end), true, false)
  }
}
# ...

If you data-bind any layout data properties, when they change, the shell containing their widget re-packs its children (calls #pack method automatically) to ensure proper relayout of all widgets.

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

Data-Binding

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

General data-binding examples:

text bind(contact, :first_name)

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

text bind(contact, 'address.street')

This 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.

text bind(contact, 'address.street', on_read: :upcase, on_write: :downcase)

This example adds on the one above it by specifying converters on read and write of the model property, like in the case of a text widget. The text widget will then displays the street upper case and the model will store it lower case. When specifying converters, read and write operations must be symmetric (to avoid an infinite update loop between the widget and the model since the widget checks first if value changed before updating)

text bind(contact, 'address.street', on_read: lambda { |s| s[0..10] })

This example also specifies a converter on read of the model property, but via a lambda, which truncates the street to 10 characters only. Note that the read and write operations are assymetric. This is fine in the case of formatting data for a read-only widget like label

text bind(contact, 'address.street') { |s| s[0..10] }

This is a block shortcut version of the syntax above it. It facilitates formatting model data for read-only widgets since it's a very common view concern. It also saves the developer from having to create a separate formatter/presenter for the model when the view can be an active view that handles common simple formatting operations directly.

`text bind(contact, 'address.street', read_only: true)

This is read-ohly data-binding. It doesn't update contact.address.street when widget text property is changed.

text bind(contact, 'addresses[1].street')

This 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.

text bind(contact, :age, computed_by: :date_of_birth)

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

text bind(contact, :name, computed_by: [:first_name, :last_name])

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

text bind(contact, 'profiles[0].name', computed_by: ['profiles[0].first_name', 'profiles[0].last_name'])

This 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.

Example from samples/hello/hello_combo.rb sample (you may copy/paste in girb):

Combo

Hello Combo

Hello Combo

class Person
  attr_accessor :country, :country_options

  def initialize
    self.country_options=["", "Canada", "US", "Mexico"]
    self.country = "Canada"
  end

  def reset_country
    self.country = "Canada"
  end
end

class HelloCombo
  include Glimmer
  def launch
    person = Person.new
    shell {
      composite {
        combo(:read_only) {
          selection bind(person, :country)
        }
        button {
          text "Reset"
          on_widget_selected do
            person.reset_country
          end
        }
      }
    }.open
  end
end

HelloCombo.new.launch

combo widget is data-bound to the country of a person. Note that it expects person object to have :country attribute and :country_options attribute containing all available countries.

List

Example from samples/hello/hello_list_single_selection.rb sample:

Hello List Single Selection

shell {
  composite {
    list {
      selection bind(person, :country)
    }
    button {
      text "Reset"
      on_widget_selected do
        person.reset_country
      end
    }
  }
}.open

list widget is also data-bound to the country of a person similarly to the combo widget. Not much difference here (the rest of the code not shown is the same).

Nonetheless, in the next example, a multi-selection list is declared instead allowing data-binding of multiple selection values to the bindable attribute on the model.

Example from samples/hello/hello_list_multi_selection.rb sample (you may copy/paste in girb):

Hello List Multi Selection

class Person
  attr_accessor :provinces, :provinces_options

  def initialize
    self.provinces_options=[
      "",
      "Quebec",
      "Ontario",
      "Manitoba",
      "Saskatchewan",
      "Alberta",
      "British Columbia",
      "Nova Skotia",
      "Newfoundland"
    ]
    self.provinces = ["Quebec", "Manitoba", "Alberta"]
  end

  def reset_provinces
    self.provinces = ["Quebec", "Manitoba", "Alberta"]
  end
end

class HelloListMultiSelection
  include Glimmer
  def launch
    person = Person.new
    shell {
      composite {
        list(:multi) {
          selection bind(person, :provinces)
        }
        button {
          text "Reset"
          on_widget_selected do
            person.reset_provinces
          end
        }
      }
    }.open
  end
end

HelloListMultiSelection.new.launch

The Glimmer code is not much different from above except for passing the :multi style to the list widget. However, the model code behind the scenes is quite different as it is a provinces array bindable to the selection of multiple values on a list widget. provinces_options contains all available province values just as expected by a single selection list and combo.

Note that in all the data-binding examples above, there was also an observer attached to the button widget to trigger an action on the model, which in turn triggers a data-binding update on the list or combo. Observers will be discussed in more details in the next section.

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

Tree

The SWT Tree widget visualizes a tree data-structure, such as an employment or composition hierarchy.

To data-bind a Tree, you need the root model, the children querying method, and the text display attribute on each child.

This involves using the bind keyword mentioned above in addition to a special tree_properties keyword that takes the children and text attribute methods.

Example:

shell {      
  @tree = tree {
    items bind(company, :owner), tree_properties(children: :coworkers, text: :name)
    selection bind(company, :selected_coworker)
  }
}

The code above includes two data-bindings:

  • Tree items, which first bind to the root node (company.owner), and then dig down via coworkers children method, using the name text attribute for displaying each tree item.
  • Tree selection, which binds the single tree item selected by the user to the attribute denoted by the bind keyword

Additionally, Tree items data-binding automatically stores each node model unto the SWT TreeItem object via setData method. This enables things like searchability.

The tree widget in Glimmer is represented by a subclass of WidgetProxy called TreeProxy. TreeProxy includes a depth_first_search method that takes a block to look for a tree item.

Example:

found_array = @tree.depth_first_search { |tree_item| tree_item.getData == company.owner }

This finds the root node. The array is a Java array. This enables easy passing of it to SWT Tree#setSelection method, which expects a Java array of TreeItem objects.

To edit a tree, you must invoke TreeProxy#edit_selected_tree_item or TreeProxy#edit_tree_item. This automatically leverages the SWT TreeEditor custom class behind the scenes, displaying a text widget to the user to change the selected or passed tree item text into something else. It automatically persists the change to items data-bound model on ENTER/FOCUS-OUT or cancels on ESC/NO-CHANGE.

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. It is hidden when observing widgets, and used explicitly when observing models.

Observing Widgets

Glimmer supports observing widgets with two main types of events:

  1. on_{swt-listener-method-name}: where swt-listener-method-name is replaced with the lowercase underscored event method name on an SWT listener class (e.g. on_verify_text for org.eclipse.swt.events.VerifyListener#verifyText).
  2. on_event_{swt-event-constant}: where swt-event-constant is replaced with an org.eclipse.swt.SWT event constant (e.g. on_event_show for SWT.Show to observe when widget becomes visible)

Additionally, there are two more types of events:

  • SWT display supports global listeners called filters that run on any widget. They are hooked via on_event_{swt-event-constant}
  • SWT display supports Mac application menu item observers (on_about and on_preferences), which you can read about under Miscellaneous.

Number 1 is more commonly used in SWT applications, so make it your starting point. Number 2 covers events not found in number 1, so look into it if you don't find an SWT listener you need in number 1.

Regarding number 1, to figure out what the available events for an SWT widget are, check out all of its add***Listener API methods, and then open the listener class argument to check its "event methods".

For example, if you look at the Button SWT API: https://help.eclipse.org/2019-12/index.jsp?topic=%2Forg.eclipse.platform.doc.isv%2Freference%2Fapi%2Forg%2Feclipse%2Fswt%2Fbrowser%2FBrowser.html

It has addSelectionListener. Additionally, under its Control super class, it has addControlListener, addDragDetectListener, addFocusListener, addGestureListener, addHelpListener, addKeyListener, addMenuDetectListener, addMouseListener, addMouseMoveListener, addMouseTrackListener, addMouseWheelListener, addPaintListener, addTouchListener, and addTraverseListener

Suppose, we select addSelectionListener, which is responsible for what happens when a user selects a button (clicks it). Then, open its argument SelectionListener SWT API, and you find the event (instance) methods: widgetDefaultSelected and widgetSelected​. Let's select the second one, which is what gets invoked when a button is clicked.

Now, Glimmer simplifies the process of hooking into that listener (observer) by neither requiring you to call the addSelectionListener method nor requiring you to implement/extend the SelectionListener API.

Instead, simply add a on_widget_selected followed by a Ruby block containing the logic to perform. Glimmer figures out the rest.

Let's revisit the Tic Tac Toe example shown near the beginning of the page:

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(row, column)
          }
        }
      }
    }
  }
}

Note that every Tic Tac Toe grid cell has its text and enabled properties data-bound to the sign and empty attributes on the TicTacToe::Board model respectively.

Next however, each of these Tic Tac Toe grid cells, which are clickable buttons, have an on_widget_selected observer, which once triggered, marks the cell on the TicTacToe::Board to make a move.

Regarding number 2, you can figure out all available events by looking at the org.eclipse.swt.SWT API:

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

Example (you may copy/paste in girb):

SWT.Show - hooks a listener for showing a widget (using on_event_show in Glimmer) SWT.Hide - hooks a listener for hiding a widget (using on_event_hide in Glimmer)

shell {
  @button1 = button {
    text "Show 2nd Button"
    visible true
    on_event_show {
      @button2.swt_widget.setVisible(false)
    }
    on_widget_selected {
      @button2.swt_widget.setVisible(true)
    }
  }
  @button2 = button {
    text "Show 1st Button"
    visible false
    on_event_show {
      @button1.swt_widget.setVisible(false)
    }
    on_widget_selected {
      @button1.swt_widget.setVisible(true)        
    }
  }
}.open

Gotcha: SWT.Resize event needs to be hooked using on_event_Resize because org.eclipse.swt.SWT has 2 constants for resize: RESIZE and Resize, so it cannot infer the right one automatically from the underscored version on_event_resize

Alternative Syntax

Instead of declaring a widget observer using on_*** syntax inside a widget content block, you may also do so after the widget declaration by invoking directly on the widget object.

Example (you may copy/paste in girb):

@shell = shell {
  label {
    text "Hello, World!"
  }
}
@shell.on_shell_iconified {
  @shell.close
}  
@shell.open

The shell declared above has been modified so that the minimize button works just like the close button. Once you minimize the shell (iconify it), it closes.

The alternative syntax can be helpful if you prefer to separate Glimmer observer declarations from Glimmer GUI declarations, or would like to add observers dynamically based on some logic later on.

Observing Models

Glimmer DSL includes an observe keyword used to register an observer by passing in the observable and the property(ies) to observe, and then specifying in a block what happens on notification.

class TicTacToe
  include Glimmer

  def initialize
    # ...
    observe(@tic_tac_toe_board, :game_status) { |game_status|
      display_win_message if game_status == Board::WIN
      display_draw_message if game_status == Board::DRAW
    }
  end
  # ...
end

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

Look at samples/elaborate/tictactoe/tic_tac_toe.rb for more details starting with the code included below.

class TicTacToe
  include Glimmer
  include Observer

  def initialize
    # ...
    observe(@tic_tac_toe_board, :game_status) { |game_status|
      display_win_message if game_status == Board::WIN
      display_draw_message if game_status == Board::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.swt_widget)
    message_box.setText("Game Over")
    message_box.setMessage(message)
    message_box.open
    @tic_tac_toe_board.reset
  end
  # ...
end

Custom Widgets

Glimmer supports creating custom widgets with minimal code, which automatically extends Glimmer's DSL syntax with an underscored lowercase keyword.

Simply create a new class that includes Glimmer::UI::CustomWidget and put Glimmer DSL code in its #body block (its return value is stored in #body_root attribute). Glimmer will then automatically recognize this class by convention when it encounters a keyword matching the class name converted to underscored lowercase (and namespace double-colons :: replaced with double-underscores __)

Example (you may copy/paste in girb):

Definition:

class RedLabel
  include Glimmer::UI::CustomWidget

  body {
    label(swt_style) {
      background :red
    }
  }
end

Usage:

shell {
  red_label {
    text 'Red Label'
  }
}.open

As you can see, RedLabel became Glimmer DSL keyword: red_label

Another Example (you may copy/paste in girb):

Definition:

module Red
  class Composite
    include Glimmer::UI::CustomWidget

    before_body {
      @color = :red
    }

    body {
      composite(swt_style) {
        background @color
      }
    }
  end
end

Usage:

shell {
  red__composite {
    label {
      foreground :white
      text 'This is showing inside a Red Composite'
    }
  }
}.open

Notice how Red::Composite became red__composite with double-underscore, which is how Glimmer Custom Widgets signify namespaces by convention. Additionally, before_body hook was utilized to set a @color variable and use inside the body.

Keep in mind that namespaces are not needed to be specified if the Custom Widget class has a unique name, not clashing with a basic SWT widget or another custom widget name.

Custom Widgets have the following attributes available to call from inside the #body method:

  • #parent: Glimmer object parenting custom widget
  • #swt_style: SWT style integer. Can be useful if you want to allow consumers to customize a widget inside the custom widget body
  • #options: a hash of options passed in parentheses when declaring a custom widget (useful for passing in model data) (e.g. calendar(events: events)). Custom widget class can declare option names (array) with ::options class method as shown below, which generates attribute accessors for every option (not to be confused with #options instance method for retrieving options hash containing names & values)
  • #content: nested block underneath custom widget. It will be automatically called at the end of processing the custom widget body. Alternatively, the custom widget body may call content.call at the place where the content is needed to show up as shown in the following example.
  • #body_root: top-most (root) widget returned from #body method.
  • #swt_widget: actual SWT widget for body_root

Additionally, custom widgets can call the following class methods:

  • ::options(*option_names): declares a list of options by taking an option name array (symbols/strings). This generates option attribute accessors (e.g. options :orientation, :bg_color generates #orientation, #orientation=(v), #bg_color, and #bg_color=(v) attribute accessors)
  • ::option(option_name, default: nil): declares a single option taking option name and default value as arguments (also generates attribute accessors just like ::options)

Content/Options Example (you may copy/paste in girb):

Definition:

class Sandwich
  include Glimmer::UI::CustomWidget

  options :orientation, :bg_color
  option :fg_color, default: :black

  body {
    composite(swt_style) { # gets custom widget style
      fill_layout orientation # using orientation option
      background bg_color # using container_background option
      label {
        text 'SANDWICH TOP'
      }
      content.call # this is where content block is called
      label {
        text 'SANDWICH BOTTOM'
      }
    }
  }
end

Usage:

shell {
  sandwich(:no_focus, orientation: :vertical, bg_color: :red) {
    label {
      background :green
      text 'SANDWICH CONTENT'
    }
  }
}.open

Notice how :no_focus was the swt_style value, followed by the options hash {orientation: :horizontal, bg_color: :white}, and finally the content block containing the label with 'SANDWICH CONTENT'

Last but not least, these are the available hooks:

  • before_body: takes a block that executes in the custom widget instance scope before calling body. Useful for initializing variables to later use in body
  • after_body: takes a block that executes in the custom widget instance scope after calling body. Useful for setting up observers on widgets built in body (set in instance variables) and linking to other shells.

Gotcha

Beware of defining a custom attribute that is a common SWT widget property name. For example, if you define text= and text methods to accept a custom text and then later you write this body:

# ...
def text
  # ...
end

def text=(value)
  # ...
end

body {
  composite {
    label {
      text "Hello"
    }
    label {
      text "World"
    }
  }
}
# ...

The text method invoked in the custom widget body will call the one you defined above it. To avoid this gotcha, simply name the text property above something else, like custom_text.

Custom Shells

Custom shells are a kind of custom widgets that have shells only as the body root. They can be self-contained applications that may be opened and hidden/closed independently of the main app.

They may also be chained in a wizard fashion.

Example (you may copy/paste in girb):

class WizardStep
  include Glimmer::UI::CustomShell

  options :number, :step_count

  before_body {
    @title = "Step #{number}"
  }

  body {
    shell {
      text "Wizard - #{@title}"
      minimum_size 200, 100
      fill_layout :vertical
      label(:center) {
        text @title
        font height: 30
      }
      if number < step_count
        button {
          text "Go To Next Step"
          on_widget_selected {
            body_root.hide
          }
        }
      end
    }
  }
end

shell { |app_shell|
  text "Wizard"
  minimum_size 200, 100
  @current_step_number = 1
  @wizard_steps = 5.times.map { |n|
    wizard_step(number: n+1, step_count: 5) {
      on_event_hide {
        if @current_step_number < 5
          @current_step_number += 1
          app_shell.hide
          @wizard_steps[@current_step_number - 1].open
        end
      }      
    }
  }
  button {
    text "Start"
    font height: 40
    on_widget_selected {
      app_shell.hide
      @wizard_steps[@current_step_number - 1].open
    }
  }
}.open

Miscellaneous

Application Menu Items (About/Preferences)

Mac applications always have About and Preferences menu items. Glimmer provides widget observer hooks for them on the display:

  • on_about: executes code when user selects App Name -> About
  • on_preferences: executes code when user selects App Name -> Preferences or hits 'CMD+,' on the Mac

Example (you may copy/paste in girb):

class Example
  def initialize
    display {
      on_about {
        message_box = MessageBox.new(@shell_proxy.swt_widget)
        message_box.setText("About")
        message_box.setMessage("About Application")
        message_box.open
      }
      on_preferences {
        preferences_dialog = dialog {
          text 'Preferences'
          row_layout {
            type :vertical
            margin_left 15
            margin_top 15
            margin_right 15
            margin_bottom 15
          }
          label {
            text 'Check one of these options:'
          }
          button(:radio) {
            text 'Option 1'
          }
          button(:radio) {
            text 'Option 2'
          }
        }
        preferences_dialog.open
      }
    }
    @shell_proxy = shell {
      text 'Application Menu Items'
      fill_layout {
        margin_width 15
        margin_height 15
      }
      label {
        text 'Application Menu Items'
        font height: 30
      }
    }
    @shell_proxy.open
  end
end

Example.new

App Name and Version

Application name (shows up on the Mac in top menu bar) and version may be specified upon packaging by specifying "-Bmac.CFBundleName" and "-Bmac.CFBundleVersion" options.

Still, if you would like proper application name to show up on the Mac top menu bar during development, you may do so by invoking the SWT Display.setAppName method before any Display object has been instantiated (i.e. before any Glimmer widget like shell has been declared).

Example (you may copy/paste in girb):

Display.setAppName('Glimmer Demo')

shell(:no_resize) {
  text "Glimmer"
  label {
    text "Hello, World!"
  }
}.open

Also, you may invoke Display.setAppVersion('1.0.0') if needed for OS app version identification reasons during development, replacing '1.0.0' with your application version.

Multi-DSL Support

Glimmer supports two other DSLs in addition to the SWT DSL; that is Glimmer XML DSL and Glimmer CSS DSL. It also allows mixing DSLs, which comes in handy when doing things like using the browser widget. Glimmer automatically recognizes top-level keywords in each DSL and switches DSLs accordingly. Once done processing a top-level keyword, it switches back to the prior DSL automatically.

For example, the SWT DSL has the following top-level keywords:

  • shell
  • display
  • color
  • observe
  • async_exec
  • sync_exec
XML DSL

Simply start with html keyword and add HTML inside its block using Glimmer DSL syntax. Once done, you may call to_s, to_xml, or to_html to get the formatted HTML output.

Here are all the Glimmer XML DSL top-level keywords:

  • html
  • tag: enables custom tag creation for exceptional cases by passing tag name as '_name' attribute
  • name_space: enables namespacing html tags

Element properties are typically passed as a key/value hash (e.g. section(id: 'main', class: 'accordion')) . However, for properties like "selected" or "checked", you must leave value nil or otherwise pass in front of the hash (e.g. input(:checked, type: 'checkbox') )

Example (basic HTML / you may copy/paste in girb):

@xml = html {
  head {
    meta(name: "viewport", content: "width=device-width, initial-scale=2.0")
  }
  body {
    h1 { "Hello, World!" }
  }
}
puts @xml

Output:

<html><head><meta name="viewport" content="width=device-width, initial-scale=2.0" /></head><body><h1>Hello, World!</h1></body></html>

Example (explicit XML tag / you may copy/paste in girb):

puts tag(:_name => "DOCUMENT")

Output:

<DOCUMENT/>

Example (XML namespaces using name_space keyword / you may copy/paste in girb):

@xml = name_space(:w3c) {
  html(:id => "thesis", :class => "document") {
    body(:id => "main") {
    }
  }
}
puts @xml

Output:

<w3c:html id="thesis" class="document"><w3c:body id="main"></w3c:body></w3c:html>

Example (XML namespaces using dot operator / you may copy/paste in girb):

@xml = tag(:_name => "DOCUMENT") {
  document.body(document.id => "main") {
  }
}
puts @xml

Output:

<DOCUMENT><document:body document:id="main"></document:body></DOCUMENT>
CSS DSL

Simply start with css keyword and add stylesheet rule sets inside its block using Glimmer DSL syntax. Once done, you may call to_s or to_css to get the formatted CSS output.

css is the only top-level keyword in the Glimmer CSS DSL

Selectors may be specified by s keyword or HTML element keyword directly (e.g. body) Rule property values may be specified by pv keyword or underscored property name directly (e.g. font_size)

Example (you may copy/paste in girb):

@css = css {
  body {
    font_size '1.1em'
    pv 'background', 'white'
  }

  s('body > h1') {
    background_color :red
    pv 'font-size', '2em'
  }
}
puts @css
Listing / Enabling / Disabling DSLs

Glimmer provides a number of methods on Glimmer::DSL::Engine to configure DSL support or inquire about it:

  • Glimmer::DSL::Engine.dsls: Lists available Glimmer DSLs
  • Glimmer::DSL::Engine.disable_dsl(dsl_name): Disables a specific DSL. Useful when there is no need for certain DSLs in a certain application.
  • `Glimmer::DSL::Engine.disabled_dsls': Lists disabled DSLs
  • Glimmer::DSL::Engine.enable_dsl(dsl_name): Re-enables disabled DSL
  • Glimmer::DSL::Engine.enabled_dsls=(dsl_names): Disables all DSLs except the ones specified.

Video Widget

Video Widget

Glimmer supports a video custom widget not in SWT.

You may obtain via glimmer-cw-video gem.

Browser Widget

Glimmer supports SWT Browser widget, which can load URLs or render HTML. It can even be instrumented with JavaScript when needed (though highly discouraged in Glimmer except for rare cases when leveraging a pre-existing web codebase in a desktop app).

Example loading a URL (you may copy/paste in girb):

shell {
  minimum_size 1024, 860
  browser {
    url 'http://brightonresort.com/about'
  }
}.open

Example rendering HTML with JavaScript on document ready (you may copy/paste in girb):

shell {
  minimum_size 130, 130
  @browser = browser {
    text html {
      head {
        meta(name: "viewport", content: "width=device-width, initial-scale=2.0")
      }
      body {
        h1 { "Hello, World!" }
      }
    }
    on_completed { # on load of the page execute this JavaScript
      @browser.swt_widget.execute("alert('Hello, World!');")
    }
  }
}.open

This relies on Glimmer's Multi-DSL Support for building the HTML text using Glimmer XML DSL.

Glimmer Style Guide

  • Widgets are declared with underscored lowercase versions of their SWT names minus the SWT package name.
  • Widget declarations may optionally have arguments and be followed by a block (to contain properties and content)
  • Widget blocks are always declared with curly braces
  • Widget arguments are always wrapped inside parentheses
  • Widget properties are declared with underscored lowercase versions of the SWT properties
  • Widget property declarations always have arguments and never take a block
  • Widget property arguments are never wrapped inside parentheses
  • Widget listeners are always declared starting with on_ prefix and affixing listener event method name afterwards in underscored lowercase form
  • Widget listeners are always followed by a block using curly braces (Only when declared in DSL. When invoked on widget object directly outside of GUI declarations, standard Ruby conventions apply)
  • Data-binding is done via bind keyword, which always takes arguments wrapped in parentheses
  • Custom widget body, before_body, and after_body blocks open their blocks and close them with curly braces.
  • Custom widgets receive additional arguments to SWT style called options. These are passed as the last argument inside the parentheses, a hash of option names pointing to values.

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).

If you cloned the project and followed CONTRIBUTING.md instructions, you may run all samples at once via samples/launch command:

samples/launch

Hello Samples

For "Hello, World!" type samples, check the following:

glimmer samples/hello/hello_world.rb
glimmer samples/hello/hello_browser.rb # demonstrates browser widget
glimmer samples/hello/hello_tab.rb # demonstrates tabs
glimmer samples/hello/hello_combo.rb # demonstrates combo data-binding
glimmer samples/hello/hello_list_single_selection.rb # demonstrates list single-selection data-binding
glimmer samples/hello/hello_list_multi_selection.rb # demonstrates list multi-selection data-binding
glimmer samples/hello/hello_computed.rb # demonstrates computed data-binding

Elaborate Samples

For more elaborate samples, check the following:

glimmer samples/elaborate/.rb # demonstrates basic data-binding
glimmer samples/elaborate/contact_manager.rb # demonstrates table data-binding
glimmer samples/elaborate/tic_tac_toe.rb # demonstrates a full MVC application

External Samples

Glimmer Calculator

Glimmer Calculator

Glimmer Calculator is a basic calculator sample project demonstrating data-binding and TDD (test-driven-development) with Glimmer following the MVP pattern (Model-View-Presenter).

Gladiator

Gladiator

Gladiator (short for Glimmer Editor) is a Glimmer sample project under on-going development. You may check it out to learn how to build a Glimmer Custom Shell gem.

In Production

The following production apps have been built with Glimmer:

Math Bowling LogoMath Bowling: an educational math game for elementary level kids

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 visual list of SWT widgets:

https://www.eclipse.org/swt/widgets/

Here is a textual 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 as used in widget declaration:

https://wiki.eclipse.org/SWT_Widget_Style_Bits

Here is a SWT style bit constant reference:

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

SWT Packages

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

Here are the Java packages imported:

org.eclipse.swt.*
org.eclipse.swt.widgets.*
org.eclipse.swt.layout.*
org.eclipse.swt.graphics.*
org.eclipse.swt.browser.*
org.eclipse.swt.custom.*

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

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

Nonetheless, you can disable automatic import if needed via this Glimmer configuration option:

Glimmer::Config.import_swt_packages = false

To import SWT Java packages manually instead, you have 2 options:

  1. include Glimmer::SwtPackages: lazily imports all SWT Java packages to your class, lazy-loading SWT Java class constants on first reference.

  2. java_import swt_package_class_string: immediately imports a specific Java class where swt_package_class_string is the Java full package reference of a Java class (e.g. java_import 'org.eclipse.swt.SWT')

Note: Glimmer relies on nested_imported_jruby_include_package, which automatically brings packages to nested-modules/nested-classes and sub-modules/sub-classes.

You can learn more about importing Java packages into Ruby code at this JRuby WIKI page:

https://github.com/jruby/jruby/wiki/CallingJavaFromJRuby

Logging

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

Glimmer::Config.enable_logging
Glimmer::Config.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

Packaging & Distribution

Glimmer apps may be packaged and distributed on the Mac, Windows, and Linux via these tools:

Glimmer simplifies the process of Mac packaging via the glimmer package command. It works out of the box for any application generated by Glimmer Scaffolding:

glimmer package

This will automatically generate a JAR file under ./dist directory using Warbler, which is then used to automatically generate a DMG file (and pkg/app) under ./packages/bundles using javapackager. JAR file name will match your application local directory name (e.g. MathBowling.jar for ~/code/MathBowling) DMG file name will match the humanized local directory name + dash + application version (e.g. Math Bowling-1.0.dmg for ~/code/MathBowling with version 1.0 or unspecified)

The glimmer package command will automatically set "mac.CFBundleIdentifier" to ="org.#project_name.application.#project_name". You may override by configuring as an extra argument for javapackger (e.g. Glimmer::Package.javapackager_extra_args = " -Bmac.CFBundleIdentifier=org.andymaleh.application.MathBowling")

Packaging Defaults

Glimmer employs smart defaults in packaging.

The package application name (shows up in top menu bar on the Mac) will be a human form of the app root directory name (e.g. "Math Bowling" for "MathBowling" or "math_bowling" app root directory name). However, application name and version may be specified explicitly via "-Bmac.CFBundleName" and "-Bmac.CFBundleVersion" options.

Also, the package will only include these directories: app, config, db, lib, script, bin, docs, fonts, images, sounds, videos

After running once, you will find a config/warble.rb file. It has the JAR packaging configuration. You may adjust included directories in it if needed, and then rerun glimmer package and it will pick up your custom configuration. Alternatively, if you'd like to customize the included directories to begin with, don't run glimmer package right away. Run this command first:

glimmer package:config

This will generate config/warble.rb, which you may configure and then run glimmer package afterwards.

Packaging Configuration

  • Ensure you have a Ruby script under bin directory that launches the application, preferably matching your project directory name (e.g. bin/math_bowling) : ruby require_relative '../app/my_application.rb'
  • Include Icon (Optional): If you'd like to include an icon for your app (.icns format on the Mac), place it under package/macosx matching the humanized application local directory name (e.g. 'Math Bowling.icns' [containing space] for MathBowling or math_bowling). You may generate your Mac icon easily using tools like Image2Icon (http://www.img2icnsapp.com/) or manually using the Mac terminal command iconutil (iconutil guide: https://applehelpwriter.com/tag/iconutil/)
  • Include Version (Optional): Create a VERSION file in your application and fill it your app version on one line (e.g. 1.1.0)
  • Include License (Optional): Create a LICENSE.txt file in your application and fill it up with your license (e.g. MIT). It will show up to people when installing your app. Note that, you may optionally also specify license type, but you'd have to do so manually via -BlicenseType=MIT shown in an example below.
  • Extra args (Optional): You may optionally add the following to Rakefile to configure extra arguments for javapackager: Glimmer::Packager.javapackager_extra_args = "..." (Useful to avoid re-entering extra arguments on every run of rake task.). Read about them in their section below.

javapackager Extra Arguments

In order to explicitly configure javapackager, Mac package attributes, or sign your Mac app to distribute on the App Store, you can follow more advanced instructions for javapackager here:

The Glimmer rake task allows passing extra options to javapackager via:

  • Glimmer::Packager.javapackager_extra_args="..." in your application Rakefile
  • Environment variable: JAVAPACKAGER_EXTRA_ARGS

Example (Rakefile):

Glimmer::Package.javapackager_extra_args = '-BlicenseType="MIT" -Bmac.category="public.app-category.business" -Bmac.signing-key-developer-id-app="Andy Maleh"'

Note that mac.category defaults to "public.app-category.business", but can be overridden with one of the category UTI values mentioned here:

https://developer.apple.com/library/archive/releasenotes/General/SubmittingToMacAppStore/index.html#//apple_ref/doc/uid/TP40010572-CH16-SW8

Example (env var):

JAVAPACKAGER_EXTRA_ARGS='-Bmac.CFBundleName="Math Bowling Game"' glimmer package

That overrides the default application display name.

Mac Application Distribution

Recent macOS versions (starting with Catalina) have very stringent security requirements requiring all applications to be signed before running (unless the user goes to System Preferences -> Privacy -> General tab and clicks "Open Anyway" after failing to open application the first time they run it). So, to release a desktop application on the Mac, it is recommended to enroll in the Apple Developer Program to distribute on the Mac App Store or otherwise request app notarization from Apple to distribute independently.

Afterwards, you may add developer-id/signing-key arguments to javapackager via Glimmer::Package.javapackager_extra_args or JAVAPACKAGER_EXTRA_ARGS according to this webpage: https://docs.oracle.com/javase/9/tools/javapackager.htm#JSWOR719

DMG signing key argument:

-Bmac.signing-key-developer-id-app="..."

PKG signing key argument:

-Bmac.signing-key-developer-id-installer="..."

Mac App Store signing key arguments:

-Bmac.signing-key-app="..."
-Bmac.signing-key-pkg="..."

Self Signed Certificate

You may still release a signed DMG file without enrolling into the Apple Developer Program with the caveat that users will always fail in opening the app the first time, and have to go to System Preferences -> Privacy -> General tab to "Open Anyway".

To do so, you may follow these steps (abbreviated version from https://developer.apple.com/library/archive/documentation/Security/Conceptual/CodeSigningGuide/Procedures/Procedures.html#//apple_ref/doc/uid/TP40005929-CH4-SW2):

  • Open Keychain Access
  • Choose Keychain Access > Certificate Assistant > Create Certificate ...
  • Enter Name (referred to below as "CertificateName")
  • Set 'Certificate Type' to 'Code Signing'
  • Create (if you alternatively override defaults, make sure to enable all capabilities)
  • Add the following option to javapackager: -Bmac.signing-key-developer-id-app="CertificateName" via Glimmer::Package.javapackager_extra_args or JAVAPACKAGER_EXTRA_ARGS

Example:

Glimmer::Package.javapackager_extra_args = '-Bmac.signing-key-developer-id-app="Andy Maleh"'

Now, when you run glimmer package, it builds a self-signed DMG file. When you make available online, and users download, upon launching application, they are presented with your certificate, which they have to sign if they trust you in order to use the application.

Gotchas

  1. Specifying License File

The javapackager documentation states that a license file may be specified with "-BlicenseFile" javapackager option. However, in order for that to work, one must specify as a source file via "-srcfiles" javapackager option. Keep that in mind if you are not going to rely on the default LICENSE.txt support.

Example:

Glimmer::Package.javapackager_extra_args = '-srcfiles "ACME.txt" -BlicenseFile="ACME.txt" -BlicenseType="ACME"'
  1. Mounted DMG Residue

If you run glimmer package multiple times, sometimes it leaves a mounted DMG project in your finder. Unmount before you run the command again or it might fail with an error saying: "Error: Bundler "DMG Installer" (dmg) failed to produce a bundle."

By the way, keep in mind that during normal operation, it does also indicate a false-negative while completing successfully similar to the following (please ignore): 

Exec failed with code 2 command [[/usr/bin/SetFile, -c, icnC, /var/folders/4_/g1sw__tx6mjdgyh3mky7vydc0000gp/T/fxbundler4076750801763032201/images/MathBowling/.VolumeIcon.icns] in unspecified directory

Resources

Help

Issues

You may submit issues on GitHub.

Click here to submit an issue.

IRC Channel

If you need live help, try the #glimmer IRC channel on irc.mibbit.net. If no one was available, you may leave a GitHub issue to schedule a meetup on IRC.

Click here to connect to #glimmer IRC channel immediately via a web interface.

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

Click here to view contributor commits.

License

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