R2D is a graphics interface for drawing 2D graphics, animations, playing audio, capturing input, and more.

This library is in very early development, which means the design direction, implementation, and final API spec is still in flux. Please contact me or open an issue before sending a pull request.

View the Roadmap in the wiki.

Until a v0.1.0 release, this gem will only be available locally. To build and install the gem, use:

$ gem build r2d.gemspec
$ gem install r2d-0.0.0.gem

require 'r2d'

# Configure and initialize the window
window width: 640, height: 480

# Create a shape and add it to the window
r = Rectangle.new(0, 0, 100, 100, "blue")

# Show the window
window :show

Read the reference below to learn about all the things you can do with R2D. See the examples directory for more sample applications.

x = an 'x'  coordinate (Integer)
y = an 'y'  coordinate (Integer)
s = the size    (Integer)
w = the width   (Integer)
h = the height  (Integer)

c = the color  (String)
or...
c = [r, g, b, a] (Array)
  where elements are 0..255 (Integer) or 0.0..1.0 (Float)
    r = red
    g = green
    b = blue
    a = alpha

All objects that can be drawn have the methods:

add, remove, show, hide

add and show, along with remove and hide are aliased.

Parameters:

x, y, size, color="white", visible=true

Instance methods:

x/=, y/=, size=, color=

Examples:

s = Square.new(x, y, size)
s = Square.new(x, y, size, color, false)

s.x = 10
s.y = 20
s.size = 25
s.color = "red"
s.color = [250, 0, 0, 100]

Parameters:

x, y, width, height, color="white", visible=true

Instance methods:

x/=, y/=, width/=, height/=, color=

Examples:

r = Rectangle.new(x, y, width, height)
r = Rectangle.new(x, y, width, height, color, false)

r.x = 10
r.y = 20
r.width = 200
r.height = 50
r.color = "blue"
r.color = [0, 0, 255, 150]

Parameters:

x1, y1, x2, y2, x3, y3, x4, y4, color="white", visible=true

Instance methods:

x1/=, y1/=, x2/=, y2/=, x3/=, y3/=, x4/=, y4/=, color=

Examples:

q = Quad.new(x1, y1, x2, y2, x3, y3, x4, y4)
q = Quad.new(x1, y1, x2, y2, x3, y3, x4, y4, color, false)

q.x1 = 10
q.y1 = 20
q.color = "blue"
q.color = [0, 0, 255, 150]

Parameters:

x1, y1, x2, y2, x3, y3, color="white", visible=true

Instance methods:

x1/=, y1/=, x2/=, y2/=, x3/=, y3/=, color=

Examples:

t = Triangle.new(x1, y1, x2, y2, x3, y3)
t = Triangle.new(x1, y1, x2, y2, x3, y3, color, false)

t.x1 = 10
t.y1 = 20
t.color = "red"
t.color = [0, 0, 255, 1]

Formats supported: BMP, PNG, JPG.

Parameters:

x, y, "path_to_image", visible=true

Instance methods:

x, y, width/=, height/=

Examples:

img = Image.new(x, y, "ruby.png")
img = Image.new(x, y, "media/ruby.png", false)

img.x = 10
img.y = 20
img.width = 125
img.height  # returns height

Parameters:

x, y, h, "content", c="white", visible=true

Instance methods:

x/=, y/=, content=, color=

Examples:

t = Text.new(x, y, 20, "hello world")
t = Text.new(x, y, 20, "hello world", "blue", false)

t.x = 10
t.y = 20

To capture a single key press where <key_string> is any valid keyboard character a..z, A..Z, 0..9, and string representing arrows, alt, control, shift, etc:

on_key <key_string> do
  #...
end

Example:

on_key 'a' do
  # letter 'a' pressed
end

Do something repeatedly as a key is held down.

key_down <key_string> do
  #...
end

Example:

key_down 's' do
  # letter 's' held down
end

Valid character strings:

('a'..'z') || ('A'..'Z') || ('0'..'9')
'up'
'down'
'left'
'right'
'left_alt'
'right_alt'
'left_control'
'right_control'
'left_shift'
'right_shift'
'backspace'
'delete'
'space'
'tab'
'return'
'mouse_left'
'mouse_right'

Use these helper methods to get the position of the cursor. Mouse positions are relative to the top left corner of the window.

         # Returns the mouse:
mouse_x  #  x-coordinate
mouse_y  #  y-coordinate

R2D will create and manage a window instance for you. The window method is provided to send commands to the window instance.

Attributes change the appearance and behavior of the window. These are applied before drawing is done.

                     # Defaults:
title: "My App"      #  "R2D"
width: 400           #  640
height: 300          #  480
cursor: false        #  `true`
background: "white"  #  "black"

Example:

window title: 'My App', width: 300, height: 200, cursor: false

To remove all objects from the window, use:

window :clear

Note this does not delete the objects themselves – the references remain intact. This is equivalent to calling shape.remove.

Do something each time the graphic environment is updated (60 times / second).

update do
  # do something
end

Examples:

update do
  if key_down? <key_string>
    # do something
  end
end