# Paste: mandel.rb

Author: DW ruby Mon, 28 Sep 2009 01:56:46
Plain Text |
```require 'complex'

WIDTH,HEIGHT = 640,480
MAX_COLOR = 360
ZOOM_FACT = 0.8
MAX_ITERATIONS = 40
CENTER = -0.65

X_INC = WIDTH / (200000 * ZOOM_FACT)
Y_INC = HEIGHT / (150000 * ZOOM_FACT)

SAT = 0.85
VAL = 0.85

class HSV
def initialize h, s, v
@h,@s,@v = h,s,v
end

def hi
(@h / 60).floor % 6
end

def f
@h / 60 - hi
end

def p
(1 - @s) * @v
end

def q
(1 - f * @s) * @v
end

def t
(1 - ((1 - f) * @s)) * @v
end

def to_rgb
h = hi
case h
when 0
[@v, t, p]
when 1
[q, @v, p]
when 2
[p, @v, t]
when 3
[p, q, @v]
when 4
[t, p ,@v]
else
[@v, p, q]
end
end
end

def scale x
return (x * 255).to_i
end

def scale_rgb rgb
[scale(rgb[0]),scale(rgb[1]),scale(rgb[2])]
end

def make_color_map nb_cols
out = []
nb_cols.times do |i|
hsv = HSV.new((360.0 * i) / (nb_cols + 1), SAT, VAL)
color = scale_rgb hsv.to_rgb
out << ('' << color[0] << color[1] << color[2])
end
out
end

COLOR_MAP = make_color_map [MAX_ITERATIONS,MAX_COLOR].min

def c i,j
Complex(X_INC * i + CENTER - X_INC * WIDTH / 2, Y_INC * j - Y_INC * HEIGHT / 2)
end

class Complex
def absq
real**2 + image**2
end
end

def pixel c
z = Complex(0)
(-1..MAX_ITERATIONS).reverse_each do |i|
z = z**2 + c
if z.absq >= 4.0
return i
end
end
return nil
end

def color iterations
if iterations != nil
COLOR_MAP[iterations % COLOR_MAP.length]
else
return "\0\0\0"
end
end

def render
HEIGHT.times do |j|
WIDTH.times do |i|
print color pixel(c i,j)
end
end
end