Initial commit

README.md

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+#Barnsley fern
+
+_original_barnsley_fern.py_ - Implementation of Barnsley Fern 
+with Python's turtle module
+
+_enhanced_barnsley_fern.py_ - Draws Barnsley fern with minor
+variations compared to the original.
+
+These scripts can be invoked from command line directly. Like:
+./enhanced_barnsley_fern.py Make sure you chmod +x the file you'd
+like to run.
+
+Invoke programs with --help to see command-line options (background color,
+fern color, size etc.).

enhanced_barnsley_fern.py

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+#!/usr/bin/env python3
+import argparse
+from turtle import Turtle
+import random
+
+def parse_args():
+    parser = argparse.ArgumentParser(
+        description="Draw Barnsley fern using Python's Turtle graphics.")
+    parser.add_argument('-d', '--dots',  metavar='number',
+                        help='Number of dots to draw. Deefault is 20000',
+                        type=int, default=20000)
+    parser.add_argument('-bg', '--background',  metavar='color',
+                        type=str, default='white',
+                        help='Sets background color.')
+    parser.add_argument('-fg', '--foreground',  metavar='color',
+                        type=str, default='green',
+                        help='Sets pen color color.')
+    parser.add_argument('-s', '--scale',  metavar='pixels',
+                        type=int, default=500,
+                        help='Chooses scale. Default is 500 pixels.')
+    parser.add_argument('-ww', '--width', metavar='pixels',
+                        type=int, default=600,
+                        help='Window width.')
+    parser.add_argument('-wh', '--height', metavar='pixels',
+                        type=int, default=800,
+                        help='Window height.')
+    args = parser.parse_args()    
+    return args
+
+def draw_fern(pen):
+    x = 0.5
+    y = 0.0
+    for i in range(args.dots):
+        r = random.randint(0, 100)
+        if r <= 1:
+            tempx = 0.5
+            tempy = 0.16 * y
+        elif r <= 8:
+            tempx = 0.2 * x - 0.26 * y + 0.400
+            tempy = 0.23 * x + 0.22 * y - 0.045
+        elif r <= 15:
+            tempx = -0.15 * x + 0.28 * y + 0.575
+            tempy = 0.26 * x + 0.24 * y - 0.086
+        else:
+            tempx = 0.85 * x + 0.04 * y + 0.075
+            tempy = -0.04 * x + 0.850 * y + 0.180
+        if r == 100:
+            r = 0
+        r += 1
+        x, y = tempx, tempy
+        pen.setpos(x * args.scale - args.scale // 2, y * args.scale - args.scale // 2)
+        pen.dot(1)
+
+def setup_pen():
+    pen = Turtle()
+    pen.speed(0)
+    pen.ht()
+    pen.pu()
+    pen.screen.setup (width=args.width, height=args.height)
+    pen.screen.title('Barnsley fern')
+    pen.screen.bgcolor(args.background)
+    pen.screen.tracer(n=15000) # skips frames to speed up drawing
+    pen.color(args.foreground)
+    return pen
+
+if __name__ == '__main__':
+    args = parse_args()
+    pen = setup_pen()
+    draw_fern(pen)
+    input('All done!\nPress Enter to quit')
+    exit()

original_barnsley_fern.py

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+#!/usr/bin/env python3
+import argparse
+from turtle import RawPen, Screen
+import random
+
+def parse_args():
+    parser = argparse.ArgumentParser(
+        description="Draw Barnsley's fern using Python's Turtle graphics.")
+    parser.add_argument('-d', '--dots',  metavar='number',
+                        help='Number of dots to draw.',
+                        type=int, default=20000)
+    parser.add_argument('-bg', '--background',  metavar='color',
+                        type=str, default='white',
+                        help='Background color.')
+    parser.add_argument('-fg', '--foreground',  metavar='color',
+                        type=str, default='green',
+                        help='Drawing color.')
+    parser.add_argument('-s', '--scale',  metavar='pixels',
+                        type=int, default=50,
+                        help='Choose scale. Default is 50 pixels.')
+    parser.add_argument('-ww', '--width', metavar='pixels',
+                        type=int, default=600,
+                        help='Window width.')
+    parser.add_argument('-wh', '--height', metavar='pixels',
+                        type=int, default=800,
+                        help='Window width.')
+    args = parser.parse_args()    
+    return args
+
+def draw(root):
+    pen = RawPen(root)
+    pen.speed(0)
+    pen.ht()
+    pen.pu()
+    pen.screen.bgcolor(args.background)
+    x = 0.0
+    y = 0.0
+    for i in range(args.dots):
+        r = random.randint(0, 100)
+        if r <= 1:
+            tempx = 0.0
+            tempy = 0.16 * y
+        elif r <= 7:
+            tempx = 0.2 * x - 0.26 * y 
+            tempy = 0.23 * x + 0.22 * y + 1.6
+        elif r <= 15:
+            tempx = -0.15 * x + 0.28 * y 
+            tempy = 0.26 * x + 0.24 * y + 0.44
+        else:
+            tempx = 0.85 * x + 0.04 * y 
+            tempy = -0.04 * x + 0.850 * y + 1.6
+        x, y = tempx, tempy
+        pen.setpos(x * args.scale - args.scale // 2, y * args.scale - args.scale * 3)
+        pen.dot(1, args.foreground)
+    print('All done!')
+    input('Press any key to quit')
+
+if __name__ == '__main__':
+    args = parse_args()
+    root = Screen()
+    root.setup (width=600, height=800)
+    root.title('Barnsley fern')
+    root.tracer(n=15000)
+    draw(root)