Drawille for Ruby

Draw in your terminal with Unicode Braille characters. Implementation based on drawille by @asciimoo.

Add this line to your application's Gemfile:

gem 'drawille'

And then execute:

$ bundle

Or install it yourself as:

$ gem install drawille

Drawille can be used like the Python implementation due to the similar API. Here is one of its examples:

require 'drawille'

canvas = Drawille::Canvas.new

(0..1800).step(10).each do |x| 
  canvas.set(x/10, 10 + Math.sin(x * Math::PI / 180) * 10) 
end

puts canvas.frame

But in the end you can use it in every possible situation where you have only two colors. This means it is perfect for some stencil graffitis.

require 'drawille'
require 'chunky_png'

include ChunkyPNG

canvas = Drawille::Canvas.new

def draw canvas, img, xoffset=0
  (0..img.dimension.width-1).each do |x|
    (0..img.dimension.height-1).each do |y|
      r = Color.r(img[x,y])
      g = Color.g(img[x,y])
      b = Color.b(img[x,y])
      canvas.set(x+xoffset, y) if (r + b + g) > 100
    end
  end
end

draw canvas, Image.from_file('examples/stencil-1.png')
draw canvas, Image.from_file('examples/stencil-2.jpg'), 141

puts canvas.frame

With a "flipbook" you can also create animations on your terminal.

This implementation also includes a Turtle graphics API for all your beloved fractals:

require 'drawille'

canvas = Drawille::Canvas.new

frame = canvas.paint do
  move 300, 300
  down

  36.times do
    right 10
    36.times do
      right 10
      forward 8
    end
  end

end.frame

puts frame

  canvas = Drawille::Canvas.new
  canvas.paint do
    # Move your brush with the following commands
  end

forward 10 or fw 10

Moves your brush in the current direction (default is 0 which points to the right). Please note that your brush has to be set down to actually draw.

back 10 or bk 10

Moves your brush in the opposite direction. Please note that your brush has to be set down to actually draw.

right 90 or rt 90

Turn the direction of the brush by 90 degrees to the right.

left 90 or lt 90

Turn the direction of the brush by 90 degrees to the left.

up or pu

Sets the brush up which means all following operations will have no effect on the canvas itself.

down or pd

Sets the drush down which means that moving the brush will draw a stroke.

move 100, 100 or mv 100, 100

Moves the brush to the position x=100 and y=100.

line from: [30, 20], to: [100, 100]

A line between the two given points will be drawn. The movement to the starting point will be with an up brush, but the former state of the brush will be restored after this line.

#set(x, y) / #[x, y] = true

Sets the state of the given position to true, i.e. the #frame method will render a point at [x,y].

#unset(x, y) / #[x, y] = false

Sets the state of the given position to false, i.e. the #frame method will not render a point at [x,y].

#toggle(x, y)

Toggles the state of the given position.

#clear

No point will be rendered by the #frame method.

#frame

Returns newline-delimited string of the given canvas state. Braille characters are used to represent points. Please note that a single character contains 2 x 4 pixels.

c = Drawille::Canvas.new
f = Drawille::FlipBook.new

c.paint do
  move 200, 100
  down

  36.times do
    right 10
    36.times do
      right 10
      forward 8
    end
    f.snapshot canvas
  end

end

f.play repeat: true, fps: 6

With the flip-book it is possible to create and play animations. Just draw on the canvas as usual and create a snapshot for every frame you want to be included in the animation.

FlipBook#snapshot canvas

Saves a snapshot of the current state of the canvas.

FlipBook#snapshot#play

Will render the animation on the terminal. The method also takes an option hash with the options :repeat :fps.

As an alternative to snapshots it is possible to pass a block which will be called consecutively and should return a canvas which will be rendered as a frame in the animation or nil to stop the animation.

MIT License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.