new particle example and more bug fixes

README.md

@@ -104,4 +104,5 @@ You can see a list of examples in the examples folder, but here is a quick sampl
 More example outputs:
 
 ![MacRuby Image color effects](http://img.skitch.com/20100712-jr4jfhbaw2x9nmhy7bscapgbd4.png)
-![MacRuby Image Iterate](http://img.skitch.com/20100713-1132mmahgum65tpgj9d9mag939.png)
+![MacRuby Image Iterate](http://img.skitch.com/20100713-1132mmahgum65tpgj9d9mag939.png)
+![MacRuby particles examples](http://img.skitch.com/20100713-gb3ps8psw3ppyedx1t1x426rwa.png)

examples/canvas_example.rb

@@ -29,9 +29,6 @@ def drawRect(rect)
 
 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

examples/particle_example.rb

@@ -0,0 +1,79 @@
+framework 'Cocoa'
+HERE = File.expand_path(File.dirname(__FILE__))
+require File.join(HERE, '..', 'graphics')
+require File.join(HERE, 'app_wrapper')
+
+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)
+
+      # load images and grab colors
+      img = Image.new(File.join(HERE, 'images', 'italy.jpg')).saturation(1.9)
+      red_colors = img.colors(100)
+      img = Image.new(File.join(HERE, 'images', 'v2.jpg')).saturation(1.9)
+      blue_colors = img.colors(100)
+
+      # create flower head shape
+      head = Path.new.oval(0,0,10,10,:center)
+      petals = 3
+      petals.times do
+        head.rotate(360/petals)
+        head.oval(0,10,5,5,:center)
+        head.oval(0,17,2,2,:center)
+      end
+      # randomize head attributes
+      head.randomize(:fill, red_colors)
+      head.randomize(:stroke, blue_colors)
+      head.randomize(:scale, 0.2..2.0)
+      head.randomize(:rotation, 0..360)
+
+      # create particles
+      numparticles = 200
+      numframes    = 200
+      particles    = []
+      numparticles.times do |i|
+        # start particle at random point at bottom of canvas
+        x = MRGraphics.random(c.width/2 - 50, c.width/2 + 50)
+        p = Particle.new(x,0)
+        p.velocity_x = MRGraphics.random(-0.5,0.5) # set initial x velocity
+        p.velocity_y = MRGraphics.random(1.0,3.0) # set initial y velocity
+        p.acceleration = 0.1 # set drag or acceleration
+        particles[i] = p # add particle to array
+      end
+
+      # animate particles
+      numframes.times do |frame|
+        numparticles.times do |i|
+          particles[i].move
+        end
+      end
+
+      # draw particle trails and heads
+      numparticles.times do |i|
+
+        c.push
+        # choose a stem color
+        color = MRGraphics.choose(blue_colors).a(0.7).analog(20,0.7)
+        c.stroke(color)
+        c.stroke_width(MRGraphics.random(0.5,2.0))
+
+        # draw the particle
+        particles[i].draw(c) # raising an error
+
+        # go to the last particle position and draw the flower head
+        c.translate(particles[i].points[-1][0],particles[i].points[-1][1])
+        c.draw(head)
+        c.pop
+      end
+    end
+  end
+
+end
+
+app = AppWrapper.new(800,600)
+app.window.contentView = CustomView.alloc.initWithFrame(app.frame)
+app.start

lib/canvas.rb

@@ -96,7 +96,7 @@ def initialize(options={}, &block)
       @output        = options[:filename] || 'test'
       @stacksize     = 0
       @colorspace    = CGColorSpaceCreateDeviceRGB() # => CGColorSpaceRef
-      @autoclosepath = false
+      @autoclose_path = false
 
       case options[:type]
       when :pdf
@@ -391,7 +391,7 @@ def draw(object, *args)
 
     # automatically close the path after it is ended
     def autoclose_path!
-      @autoclosepath = true
+      @autoclose_path = true
     end
 
     def autoclose_path=(bool)
@@ -416,7 +416,8 @@ def begin_path(x, y)
 
     # end the current path and draw it
     def end_path
-      CGContextClosePath(@ctx) if @autoclosepath
+      return if CGContextIsPathEmpty(@ctx)
+      CGContextClosePath(@ctx) if @autoclose_path
       mode = KCGPathFillStroke
       CGContextDrawPath(@ctx, mode) # apply fill and stroke
     end
@@ -787,14 +788,12 @@ def draw_path(p, tx=0, ty=0, iterations=1)
 
               CGContextAddPath(@ctx, p.path) if p.class == Path
               CGContextDrawPath(@ctx, KCGPathFillStroke) # apply fill and stroke
-
               # if there's an image, draw it clipped by the path
               if (p.image)
                 begin_clip(p)
                 image(p.image)
                 end_clip
               end
-
             end
           end
         end

lib/elements/particle.rb

@@ -51,8 +51,8 @@ def move
       @y += @velocity_y
 
       # randomly increase/decrease direction
-      @velocity_x += random(-1.0, 1.0) * @acceleration
-      @velocity_y += random(-1.0, 1.0) * @acceleration
+      @velocity_x += MRGraphics.random(-1.0, 1.0) * @acceleration
+      @velocity_y += MRGraphics.random(-1.0, 1.0) * @acceleration
 
       # draw a line from the old position to the new
       #CANVAS.line(@previous_x,@previous_y,@x,@y);
@@ -67,9 +67,9 @@ def move
     end
 
     def draw(canvas)
-      canvas.nofill
-      canvas.lines(@points)
+      canvas.no_fill
+      canvas.lines(@points)      
     end
 
   end
-end
+end

lib/elements/rope.rb

@@ -29,9 +29,9 @@ def initialize(canvas, options={})
 
     def hair(hair_x0=@x0, hair_y0=@y0, hair_x1=@x1, hair_y1=@y1, hair_width=@width, hair_fibers=@fibers)
       @canvas.push
-      @canvas.strokewidth(@strokewidth)
-      @canvas.autoclosepath(false)
-      @canvas.nofill
+      @canvas.stroke_width(@strokewidth)
+      @canvas.autoclose_path = false
+      @canvas.no_fill
       hair_x0 = MRGraphics.choose(hair_x0)
       hair_y0 = MRGraphics.choose(hair_y0)
       hair_x1 = MRGraphics.choose(hair_x1)
@@ -56,8 +56,8 @@ def hair(hair_x0=@x0, hair_y0=@y0, hair_x1=@x1, hair_y1=@y1, hair_width=@width,
     def ribbon(ribbon_x0=@x0, ribbon_y0=@y0, ribbon_x1=@x1, ribbon_y1=@y1, ribbon_width=@width, ribbon_fibers=@fibers)
       @canvas.push
       @canvas.strokewidth(@strokewidth)
-      @canvas.autoclosepath(false)
-      @canvas.nofill
+      @canvas.autoclose_path = false
+      @canvas.no_fill
       black = Color.black
       white = Color.white
       ribbon_x0 = MRGraphics.choose(ribbon_x0)
@@ -83,7 +83,7 @@ def ribbon(ribbon_x0=@x0, ribbon_y0=@y0, ribbon_x1=@x1, ribbon_y1=@y1, ribbon_wi
         # @canvas.oval(cpx0,cpy0,5,5,:center)
         # @canvas.fill(white)
         # @canvas.oval(cpx1,cpy1,5,5,:center)
-        # @canvas.nofill
+        # @canvas.no_fill
 
         @canvas.beginpath(x0, y0)
         @canvas.curveto(