--- /dev/null
+#!/usr/bin/env python3
+"""
+
+ sorting_animation.py
+
+A minimal sorting algorithm animation:
+Sorts a shelf of 10 blocks using insertion
+sort, selection sort and quicksort.
+
+Shelfs are implemented using builtin lists.
+
+Blocks are turtles with shape "square", but
+stretched to rectangles by shapesize()
+ ---------------------------------------
+ To exit press space button
+ ---------------------------------------
+"""
+from turtle import *
+import random
+
+
+class Block(Turtle):
+
+ def __init__(self, size):
+ self.size = size
+ Turtle.__init__(self, shape="square", visible=False)
+ self.pu()
+ self.shapesize(size * 1.5, 1.5, 2) # square-->rectangle
+ self.fillcolor("black")
+ self.st()
+
+ def glow(self):
+ self.fillcolor("red")
+
+ def unglow(self):
+ self.fillcolor("black")
+
+ def __repr__(self):
+ return "Block size: {0}".format(self.size)
+
+
+class Shelf(list):
+
+ def __init__(self, y):
+ "create a shelf. y is y-position of first block"
+ self.y = y
+ self.x = -150
+
+ def push(self, d):
+ width, _, _ = d.shapesize()
+ # align blocks by the bottom edge
+ y_offset = width / 2 * 20
+ d.sety(self.y + y_offset)
+ d.setx(self.x + 34 * len(self))
+ self.append(d)
+
+ def _close_gap_from_i(self, i):
+ for b in self[i:]:
+ xpos, _ = b.pos()
+ b.setx(xpos - 34)
+
+ def _open_gap_from_i(self, i):
+ for b in self[i:]:
+ xpos, _ = b.pos()
+ b.setx(xpos + 34)
+
+ def pop(self, key):
+ b = list.pop(self, key)
+ b.glow()
+ b.sety(200)
+ self._close_gap_from_i(key)
+ return b
+
+ def insert(self, key, b):
+ self._open_gap_from_i(key)
+ list.insert(self, key, b)
+ b.setx(self.x + 34 * key)
+ width, _, _ = b.shapesize()
+ # align blocks by the bottom edge
+ y_offset = width / 2 * 20
+ b.sety(self.y + y_offset)
+ b.unglow()
+
+def isort(shelf):
+ length = len(shelf)
+ for i in range(1, length):
+ hole = i
+ while hole > 0 and shelf[i].size < shelf[hole - 1].size:
+ hole = hole - 1
+ shelf.insert(hole, shelf.pop(i))
+ return
+
+def ssort(shelf):
+ length = len(shelf)
+ for j in range(0, length - 1):
+ imin = j
+ for i in range(j + 1, length):
+ if shelf[i].size < shelf[imin].size:
+ imin = i
+ if imin != j:
+ shelf.insert(j, shelf.pop(imin))
+
+def partition(shelf, left, right, pivot_index):
+ pivot = shelf[pivot_index]
+ shelf.insert(right, shelf.pop(pivot_index))
+ store_index = left
+ for i in range(left, right): # range is non-inclusive of ending value
+ if shelf[i].size < pivot.size:
+ shelf.insert(store_index, shelf.pop(i))
+ store_index = store_index + 1
+ shelf.insert(store_index, shelf.pop(right)) # move pivot to correct position
+ return store_index
+
+def qsort(shelf, left, right):
+ if left < right:
+ pivot_index = left
+ pivot_new_index = partition(shelf, left, right, pivot_index)
+ qsort(shelf, left, pivot_new_index - 1)
+ qsort(shelf, pivot_new_index + 1, right)
+
+def randomize():
+ disable_keys()
+ clear()
+ target = list(range(10))
+ random.shuffle(target)
+ for i, t in enumerate(target):
+ for j in range(i, len(s)):
+ if s[j].size == t + 1:
+ s.insert(i, s.pop(j))
+ show_text(instructions1)
+ show_text(instructions2, line=1)
+ enable_keys()
+
+def show_text(text, line=0):
+ line = 20 * line
+ goto(0,-250 - line)
+ write(text, align="center", font=("Courier", 16, "bold"))
+
+def start_ssort():
+ disable_keys()
+ clear()
+ show_text("Selection Sort")
+ ssort(s)
+ clear()
+ show_text(instructions1)
+ show_text(instructions2, line=1)
+ enable_keys()
+
+def start_isort():
+ disable_keys()
+ clear()
+ show_text("Insertion Sort")
+ isort(s)
+ clear()
+ show_text(instructions1)
+ show_text(instructions2, line=1)
+ enable_keys()
+
+def start_qsort():
+ disable_keys()
+ clear()
+ show_text("Quicksort")
+ qsort(s, 0, len(s) - 1)
+ clear()
+ show_text(instructions1)
+ show_text(instructions2, line=1)
+ enable_keys()
+
+def init_shelf():
+ global s
+ s = Shelf(-200)
+ vals = (4, 2, 8, 9, 1, 5, 10, 3, 7, 6)
+ for i in vals:
+ s.push(Block(i))
+
+def disable_keys():
+ onkey(None, "s")
+ onkey(None, "i")
+ onkey(None, "q")
+ onkey(None, "r")
+
+def enable_keys():
+ onkey(start_isort, "i")
+ onkey(start_ssort, "s")
+ onkey(start_qsort, "q")
+ onkey(randomize, "r")
+ onkey(bye, "space")
+
+def main():
+ getscreen().clearscreen()
+ ht(); penup()
+ init_shelf()
+ show_text(instructions1)
+ show_text(instructions2, line=1)
+ enable_keys()
+ listen()
+ return "EVENTLOOP"
+
+instructions1 = "press i for insertion sort, s for selection sort, q for quicksort"
+instructions2 = "spacebar to quit, r to randomize"
+
+if __name__=="__main__":
+ msg = main()
+ mainloop()
projects / python / commitdiff