utils.py

import cv2
import numpy as np
import matplotlib.pyplot as plt
import os

operators = ['+', '-', '/', '*', '^', '(', ')']


def isOperand(c):
    if c not in operators:
        return True
    return False


def hasLessOrEqualPriority(a, b):
    if a == '(':
        return False
    if a == '^':
        if b in ['(', '^']:
            return True
    if a in ['/', '*']:
        if b in ['(', '/', '*']:
            return True
    if a in ['+', '-']:
        return True
    if b in ['emp', ')']:
        return True
    return False


def peek(stack):
    if len(stack) == 0:
        return 'emp'
    return stack[len(stack)-1]


def evaluate(a, b, operator, imflag=False):
    if operator == '+':
        return a+b
    elif operator == '-':
        return a-b
    elif operator == '/':
        if imflag:
            cv2.imwrite('./temp.jpg', a/b)
            im = cv2.imread('./temp.jpg')
            os.remove('./temp.jpg')
            return im
        else:
            return a/b
    elif operator == '*':
        return a*b


def toPostfix(infix):
    stack = []
    infix = Wrap(infix)
    postfix = ''
    operator = ''
    opflag = False
    for c in infix:
        if isOperand(c):
            if opflag == False:
                postfix += '@'
            postfix += c
            opflag = True

        else:
            if opflag == True:
                postfix += '@'
                opflag = False

            if c == '(' or len(stack) == 0:
                stack.append(c)
            elif c == ')':
                operator = stack.pop()
                while not operator == '(':
                    postfix += operator
                    operator = stack.pop()
            else:
                while stack and not hasLessOrEqualPriority(c, peek(stack)):
                    postfix += stack.pop()
                stack.append(c)

    while (not (len(stack) == 0)):
        postfix += stack.pop()
    return postfix


def Wrap(exp):
    if exp[0] == '(' and exp[len(exp)-1] == ')':
        return exp
    else:
        return '(' + exp + ')'


def transform_Image(Image, transform, pixelrange=[]):
    transform = toPostfix(transform)
    stack = []
    opflag = False
    dig_holder = ''
    for c in transform:
        print(stack)
        if isOperand(c):
            if c == '@':
                opflag = not opflag
                if opflag == False:
                    stack.append(dig_holder)
                    dig_holder = ''
            if opflag == True:
                if c != '@':
                    dig_holder += c
        else:
            op1 = stack.pop()
            op2 = stack.pop()
            if (op1 == 'X' or op1 == 'x') and (op2 == 'x' or op2 == 'X'):
                op1 = Image
                op2 = Image
                Image = evaluate(op2, op1, c, True)
                stack.append('x')
            elif op1 == 'x' or op1 == 'X':
                op1 = Image
                op2 = int(op2)
                Image = evaluate(op2, op1, c, True)
                stack.append('x')
            elif op2 == 'x' or op2 == 'X':
                op2 = Image
                op1 = int(op1)
                Image = evaluate(op2, op1, c, True)
                stack.append('x')
            else:
                op1 = int(op1)
                op2 = int(op2)
                stack.append(evaluate(op2, op1, c))

    return Image

# transform='x/20'
# Image=cv2.imread('./Test.jpg')
# Image=transform_Image(Image,transform)
# cv2.imshow('lol',Image)
# cv2.waitKey(0)