Find a the missing value in a width/height by providing either the width or height, and any aspect ratio you'd like. This console app does the rest!

aspector.py

#	usr/bin/env python
#	MODULE:			aspector.py
#	INFO:			Enter a width or height value, then the ratio you'd like to find for
#					the missing value. This will give it to you!
#	CODED BY:		iivii
#	EMAIL:			thelibrarian@odd.codes
#	LICENSE:		Just throw me a bone and let people know I helped out okay?
#	NOTE:			Send me anything you may use this code for! I'm just curious to see
#					if anything I did was able to help you.
###########################################################################################

#################
#	IMPORTS		#
#################
import sys

#################
#	GLOBALS		#
#################
count = 0

#################
#	FUNCS		#
#################

#	Gets the aspect ratio calculations
def aspect(width=1920, height=1080):
	w = width
	h = height
	wratio, hratio = aspect_enter()

	if width is 0 or width < 0:
		find = h
	else:
		find = w

	if find == h:
		fwidth = wratio * find
		fheight = hratio
		final = fwidth/fheight
	else:
		fwidth = wratio
		fheight = hratio * find
		final = fheight/fwidth

	return final

#	Greets the user
def greet():
	print("\nTo find a width, press 1. To find height, 2.\nAnything else exits.\n")
	res = raw_input("::: ")
	if res.isalnum():
		res = int(res)
		if res is 1:
			print("\nPlease enter a width:")
			get = raw_input("::: ")
			if get.isalnum():
				get = int(get)
				outcome = aspect(int(get))
				print("\nWith a width of " + str(get) + ", the height should be: ")
				print("::: " + str(outcome))
			else:
				print("Please only enter values and not letters.")
				greet()
		elif res is 2:
			print("\nPlease enter a height:")
			get = raw_input("::: ")
			if get.isalnum():
				get = int(get)
				outcome = aspect(0, int(get))
				print("\nWith a height of " + str(get) + ", the width should be: ")
				print("::: " + str(outcome))
			else:
				print("Please only enter values and not letters.")
				greet()
	else:
		print("EXITING")
		raise(sys.exit())

#	Requests values to determine aspect ratio
def aspect_enter():
	global count
	print("Enter the first value for the ratio:")
	wr = raw_input("::: ")
	if not wr.isalnum():
		print("\nOnly enter numbers.\n")
		count += 1
		if count >= 3:
			print("Exiting, dumbass")
			raise sys.exit()
		aspect_enter()
	print("Enter the second value for the ratio:")
	hr = raw_input("::: ")
	if not hr.isalnum():
		print("\nOnly enter numbers.\n")
		count += 1
		if count >= 3:
			print("Exiting, dumbass")
			raise sys.exit()
		aspect_enter()

	wr = int(wr)
	hr = int(hr)
	count = 0
	return wr, hr


#################
#	MAINLOOP	#
#################
greet()