sparklines.rb

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		height = options[:height].to_i
		upper = options[:upper].to_i
		below_color = options[:below_color]
		above_color = options[:above_color]

		img = Magick::Image.new(results.size * 2 - 1, height) {self.background_color = options[:background_color]}
		img.format = "PNG"
		draw = Magick::Draw.new

		i=0
		results.each do |r|
			color = (r >= upper) && above_color || below_color
			draw.stroke(color)
			draw.line(i, (img.rows - r/(101.0/(height-4))-4).to_i,i,(img.rows - r/(101.0/(height-4))).to_i)
			i+=2
		end

		draw.draw(img)
		img.to_blob
	end

# Creates a continuous area sparkline
#
# * results is an array of integer values between 0 and 100 inclusive
#
# * options is a hash that takes 4 parameters:
#
# :step - An integer that determines the distance between each point on the sparkline.  Defaults to 2.
#
# :height - An integer that determines what the height of the sparkline will be.  Defaults to 14
#
# :upper - An ineger that determines the threshold for colorization purposes.  Any value less than upper will be colored using below_color, anything above and equal to upper will use above_color.  Defaults to 50.
#
# :has_min - Determines whether a dot will be drawn at the lowest value or not.  Defaulst to false.
#
# :has_max - Determines whether a dot will be drawn at the highest value or not.  Defaulst to false.
#
# :has_last - Determines whether a dot will be drawn at the last value or not.  Defaulst to false.
#
# :min_color - A string or color code representing the color that the dot drawn at the smallest value will be displayed as.  Defaults to blue.
#
# :max_color - A string or color code representing the color that the dot drawn at the largest value will be displayed as.  Defaults to green.
#
# :last_color - A string or color code representing the color that the dot drawn at the last value will be displayed as.  Defaults to red.
#
# :above_color - A string or color code representing the color to draw values above or equal the upper value.  Defaults to red.
#
# :below_color - A string or color code representing the color to draw values below the upper value. Defaults to gray.
	def self.area(results=[], options={})
		
		step = options[:step].to_i
		height = options[:height].to_i
		upper = options[:upper].to_i

		has_min = options[:has_min]
		has_max = options[:has_max]
		has_last = options[:has_last]

		min_color = options[:min_color]
		max_color = options[:max_color]
		last_color = options[:last_color]
		below_color = options[:below_color]
		above_color = options[:above_color]

		img = Magick::Image.new((results.size - 1) * step + 4, height) {self.background_color = options[:background_color]}
		img.format = "PNG"
		draw = Magick::Draw.new

		coords = [[0,(height - 3 - upper/(101.0/(height-4)))]]
		i=0
		results.each do |r|
			coords.push [(2 + i), (height - 3 - r/(101.0/(height-4)))]
			i += step
		end
		coords.push [(results.size - 1) * step + 4, (height - 3 - upper/(101.0/(height-4)))]

		#Block off the bottom half of the image and draw the sparkline
		draw.fill(above_color)
		draw.define_clip_path('top') do
			draw.rectangle(0,0,(results.size - 1) * step + 4,(height - 3 - upper/(101.0/(height-4))))
		end
		draw.clip_path('top')
		draw.polygon *coords.flatten

		#Block off the top half of the image and draw the sparkline
		draw.fill(below_color)
		draw.define_clip_path('bottom') do
			draw.rectangle(0,(height - 3 - upper/(101.0/(height-4))),(results.size - 1) * step + 4,height)
		end
		draw.clip_path('bottom')
		draw.polygon *coords.flatten

		#The sparkline looks kinda nasty if either the above_color or below_color gets the center line
		draw.fill('black')
		draw.line(0,(height - 3 - upper/(101.0/(height-4))),(results.size - 1) * step + 4,(height - 3 - upper/(101.0/(height-4))))

		#After the parts have been masked, we need to let the whole canvas be drawable again
		#so a max dot can be displayed
		draw.define_clip_path('all') do
			draw.rectangle(0,0,img.columns,img.rows)
		end
		draw.clip_path('all')
		if has_min == 'true'
			min_pt = coords[results.index(results.min)+1]
			draw.fill(min_color)
			draw.rectangle(min_pt[0]-1, min_pt[1]-1, min_pt[0]+1, min_pt[1]+1)
		end
		if has_max == 'true'
			max_pt = coords[results.index(results.max)+1]
			draw.fill(max_color)
			draw.rectangle(max_pt[0]-1, max_pt[1]-1, max_pt[0]+1, max_pt[1]+1)
		end
		if has_last == 'true'
			last_pt = coords[-2]
			draw.fill(last_color)
			draw.rectangle(last_pt[0]-1, last_pt[1]-1, last_pt[0]+1, last_pt[1]+1)
		end

		draw.draw(img)
		img.to_blob
	end

# Creates a smooth sparkline
#
# * results - an array of integer values between 0 and 100 inclusive
#
# * options - a hash that takes these optional parameters:
#
# :step - An integer that determines the distance between each point on the sparkline.  Defaults to 2.
#
# :height - An integer that determines what the height of the sparkline will be.  Defaults to 14
#
# :has_min - Determines whether a dot will be drawn at the lowest value or not.  Defaulst to false.
#
# :has_max - Determines whether a dot will be drawn at the highest value or not.  Defaulst to false.
#
# :has_last - Determines whether a dot will be drawn at the last value or not.  Defaulst to false.
#
# :min_color - A string or color code representing the color that the dot drawn at the smallest value will be displayed as.  Defaults to blue.
#
# :max_color - A string or color code representing the color that the dot drawn at the largest value will be displayed as.  Defaults to green.
#
# :last_color - A string or color code representing the color that the dot drawn at the last value will be displayed as.  Defaults to red.
	def self.smooth(results, options)
	
		step = options[:step].to_i
		height = options[:height].to_i
		min_color = options[:min_color]
		max_color = options[:max_color]
		last_color = options[:last_color]
		has_min = options[:has_min]
		has_max = options[:has_max]
		has_last = options[:has_last]
		line_color = options[:line_color]

		img = Magick::Image.new((results.size - 1) * step + 4, height.to_i) {self.background_color = options[:background_color]}
		img.format = "PNG"
		draw = Magick::Draw.new
  
		draw.stroke(line_color)
		coords = []
		i=0
		results.each do |r|
			coords.push [ 2 + i, (height - 3 - r/(101.0/(height-4))) ]
			i += step
		end
		
		my_polyline(draw, coords)

		if has_min == true
			min_pt = coords[results.index(results.min)]
			draw.fill(min_color)
			draw.rectangle(min_pt[0]-2, min_pt[1]-2, min_pt[0]+2, min_pt[1]+2)
		end
		if has_max == true
			max_pt = coords[results.index(results.max)]
			draw.fill(max_color)
			draw.rectangle(max_pt[0]-2, max_pt[1]-2, max_pt[0]+2, max_pt[1]+2)
		end
		if has_last == true
			last_pt = coords[-1]
			draw.fill(last_color)
			draw.rectangle(last_pt[0]-2, last_pt[1]-2, last_pt[0]+2, last_pt[1]+2)
		end

		draw.draw(img)
		img.to_blob
	end


	# This is a function to replace the RMagick polyline function because it doesn't seem to work properly.
	#
	# * draw - a RMagick::Draw object. 
	#
	# * arr - an array of points (represented as two element arrays)
	def self.my_polyline (draw, arr)
		i = 0
		while i < arr.size - 1
			draw.line(arr[i][0], arr[i][1], arr[i+1][0], arr[i+1][1])
			i += 1
		end
	end

	# Draw the error Sparkline.  Not implemented yet.
	def self.plot_error(options={})
		img = Magick::Image.new(40,15) {self.background_color = options[:background_color]}
		img.format = "PNG"
		draw = Magick::Draw.new
		draw.fill('red')
		draw.line(0,0,40,15)
		draw.line(0,15,40,0)
		draw.draw(img)

		img.to_blob
	end

end