MacRuby Graphics

MacRuby Graphics is a graphics library providing a simple object-oriented interface into the power of Mac OS X's Core Graphics and Core Image drawing libraries.
With a few lines of easy-to-read code, you can write scripts to draw simple or complex shapes, lines, and patterns, process and filter images, create abstract art or visualize scientific data, and much more.

Inspiration for this project was derived from Processing and NodeBox. These excellent graphics programming environments are more full-featured than MRG, but they are implemented in Java and Python, respectively. MRG was created to offer similar functionality using the Ruby programming language.

The original author of this library is James Reynolds, MacRuby Graphics was then called Ruby Cocoa Graphics and was packaged as part of Hotcocoa. I made the choice to extract it, add more examples and specs so MacRuby developers could use this library as an addon to their projects without needing HotCocoa.

Examples

You can see a list of examples in the examples folder, but here is a quick sample:

class CustomView < NSView
  include MRGraphics

  def drawRect(rect)
    dimensions = [CGRectGetWidth(rect), CGRectGetHeight(rect)]
    Canvas.for_current_context(:size => dimensions) do |c|
      c.background(Color.black)
      white = Color.white
      c.fill(white)
      c.stroke(0.2)
      c.stroke_width(1)   
      c.font("Zapfino")

      80.times do 
        c.font_size rand(170)
        c.fill(white.copy.darken(rand(0.8)))
        letters = %W{ g i a n a } 
        c.text(letters[rand(letters.size)],
                rand(c.width),
                rand(c.height))
      end
    end
  end

end

# wrapper class to keep the examples as clean/simple as possible
app = AppWrapper.new
# assign an instance of our custiom NSView to the window's content view
app.window.contentView = CustomView.alloc.initWithFrame(app.frame)
# start the app
app.start

class CustomView < NSView
  include MRGraphics

  def drawRect(rect)
    dimensions = [CGRectGetWidth(rect), CGRectGetHeight(rect)]
    Canvas.for_current_context(:size => dimensions) do |c|
      c.background(Color.white)
      c.font('Skia')
      c.font_size(14)
      # set image width,height
      w, h = [95,95]
      # set initial drawing position
      x, y = [10, c.height - h - 10]
      # load and resize two images
      img_a = Image.new(File.join(HERE, 'images', 'v2.jpg')).resize(w,h)
      img_b = Image.new(File.join(HERE, 'images', 'italy.jpg')).resize(w,h)

      # add image B to image A using each blending mode, and draw to canvas
      [:normal,:multiply,:screen,:overlay,:darken,:lighten,
        :colordodge,:colorburn,:softlight,:hardlight,:difference,:exclusion,
        :hue,:saturation,:color,:luminosity,:maximum,:minimum,:add,:atop,
        :in,:out,:over].each do |blendmode|
        img_a.reset.resize(w,h)
        img_a.blend(img_b, blendmode)
        c.draw(img_a,x,y)
        c.text(blendmode, x, y-15)
        x += w + 5
        if (x > c.width - w + 5)
          x = 10
          y -= h + 25
        end
      end
    end
  end

end

# wrapper class to keep the examples as clean/simple as possible
app = AppWrapper.new(415,730)
# assign an instance of our custiom NSView to the window's content view
app.window.contentView = CustomView.alloc.initWithFrame(app.frame)
# start the app
app.start