The Green Shoes Manual 1.1.362

Built-in Methods

All of these commands are unusual because you don't attach them with a dot. Every other method in this manual must be attached to an object with a dot. But these are built-in methods (also called: Kernel methods.) Which means no dot!

A common one is alert:

  alert "No dots in sight"

Compare that to the method reverse, which isn't a Kernel method and is only available for Arrays and Strings:

 Shoes.app do
   para "Plaster of Paris".reverse
   #=> "siraP fo retsalP"
   para [:dogs, :cows, :snakes].reverse
   #=> [:snakes, :cows, :dogs]
 end

Most Green Shoes methods for drawing and making buttons and so on are attached to slots. See the section on Slots for more.

Built-in Constants

Green Shoes also has a handful of built-in constants which may prove useful if you are trying to sniff out what release of Green Shoes is running.

DIR is a full path of green_shoes/lib.

COLORS is a complete list of colors available to the app.

FONTS is a complete list of fonts available to the app.

VERSION is a Green Shoes version.

 Shoes.app do
   para VERSION
   para fg(DIR, red)
   image File.join(DIR, '../static/gshoes-icon.png')
   para fg(FONTS.join(', '), green)
   para COLORS.map{|k, v| [k, v]}
 end

Pops up a window containing a short message.

 alert "I'm afraid I must interject!"

Please use alerts sparingly, as they are incredibly annoying! If you are using alerts to show messages to help you debug your program, try checking out the standard Ruby method puts or p methods.

If you want to make alert() thread safe, i.e. unblock main thread, use :block => false option. If you want to change window title, use :title => a string option.

Pops up a window and asks a question. For example, you may want to ask someone their name.

 if name = ask("Please, enter your name:")
   Shoes.app{para "Welcome, #{name}!"}
 end

When the above script is run, the person at the computer will see a window with a blank box for entering their name. The name will then be saved in the name variable.

Pops up a color picker window. The program will wait for a color to be picked, then gives you back a Color object. See the Color help for some ways you can use this color.

 backcolor = ask_color "Pick a background"
 Shoes.app do
   background backcolor
 end

Pops up an "Open file..." window. It's the standard window which shows all of your folders and lets you select a file to open. Hands you back the name of the file.

 filename = ask_open_file
 Shoes.app do
   para File.read(filename)
 end

Pops up a "Save file..." window, similiar to ask_open_file, described previously.

 save_as = ask_save_file
 Shoes.app do
   para save_as
 end

Pops up an "Open folder..." window. It's the standard window which shows all of your folders and lets you select a folder to open. Hands you back the name of the folder.

 folder = ask_open_folder
 Shoes.app do
   para Dir.entries(folder)
 end

Pops up a "Save folder..." window, similiar to ask_open_folder, described previously.

 save_to = ask_save_folder
 Shoes.app do
   para save_to
 end

Pops up a yes-or-no question. If the person at the computer, clicks yes, you'll get back a true. If not, you'll get back false.

 if confirm("Draw a circle?")
  Shoes.app{ oval top: 0, left: 0, radius: 50 }
 end

Stops your program. Call this anytime you want to suddenly call it quits.

PLEASE NOTE: If you need to use Ruby's own exit method (like in a forked Ruby process,) call Kernel.exit.

Loads a TrueType (or other type of font) from a file. While TrueType is supported by all platforms, your platform may support other types of fonts. Shoes uses each operating system's built-in font system to make this work.

Note: Green Shoes doesn't support font method so far.

Here's a rough idea of what fonts work on which platforms:

• Bitmap fonts (.bdf, .pcf, .snf) - Linux
• Font resource (.fon) - Windows
• Windows bitmap font file (.fnt) - Linux, Windows
• PostScript OpenType font (.otf) - Mac OS X, Linux, Windows
• Type1 multiple master (.mmm) - Windows
• Type1 font bits (.pfb) - Linux, Windows
• Type1 font metrics (.pfm) - Linux, Windows
• TrueType font (.ttf) - Mac OS X, Linux, Windows
• TrueType collection (.ttc) - Mac OS X, Linux, Windows

If the font is properly loaded, you'll get back an array of font names found in the file. Otherwise, nil is returned if no fonts were found in the file.

Also of interest: the Shoes::FONTS constant is a complete list of fonts available to you on this platform. You can check for a certain font by using include?.

  if Shoes::FONTS.include? "Coolvetica"
    alert "Coolvetica is available on this system."
  else
    alert "You do not have the Coolvetica font."
  end

If you have trouble with fonts showing up, make sure your app loads the font before it is used. Especially on OS X, if fonts are used before they are loaded, the font cache will tend to ignore loaded fonts.

Builds a linear gradient from two colors. For each color, you may pass in a color/rgb method or a string describing the color. The gradient(green, red) is the same as green..red for example. Also possible to use different kind of args like this: gradient(green, '#FA3')

 Shoes.app do
   oval 100, 100, 100,
     fill: gradient(green, '#FA3'), angle: 45
 end

Create a grayscale color from a level of darkness and, optionally, an alpha level.

 Shoes.app do
  nostroke
  11.times do |i|
    y = x = 50 + 10 * i
    r = 200 - 10 * i
    oval x, y, r, fill: gray(1-i*0.1)
  end
 end

Create a color from red, green and blue components. An alpha level (indicating transparency) can also be added, optionally.

When passing in a whole number, use values from 0 to 255.

 Shoes.app do
   blueviolet = rgb(138, 43, 226, 0.5)
   darkgreen = rgb(0, 100, 0, 0.5)
   oval 100, 100, 100,
     fill: [blueviolet, darkgreen].sample(1)
 end

Or, use a decimal number from 0.0 to 1.0.

 Shoes.app do
   blueviolet = rgb(0.54, 0.17, 0.89)
   darkgreen = rgb(0, 0.4, 0)
   oval 100, 100, 100,
     fill: [blueviolet, darkgreen].sample(1)
 end

Next: The App Object