gistfile1.txt

#!/usr/bin/python
# Given the resolution and diagonal, calculate the mm size of the screen and the ppi

import sys, math

MM_IN_INCH = 25.4

def size_and_ppi_from_resolution_and_diagonal(x, y, d): # pix, pix, mm
		x, y, d = float(x), float(y), float(d)

		ratio = x/y
		y_mm = d / math.sqrt( 1 + ratio**2 )
		x_mm = y_mm * ratio

		d_pix = math.sqrt(x**2 + y**2)
		d_in = d / MM_IN_INCH
		ppi = d_pix / d_in

		return x_mm, y_mm, ppi

if __name__ == '__main__':
		if len(sys.argv) < 4:
				print 'Usage:', sys.argv[0], ' x_res y_res diagonal (inches)'
				exit(1)
		x, y, d = float(sys.argv[1]), float(sys.argv[2]), float(sys.argv[3])*MM_IN_INCH
		x_mm, y_mm, ppi = size_and_ppi_from_resolution_and_diagonal(x, y, d)
		print x_mm, 'mm'
		print y_mm, 'mm'
		print ppi, 'PPI'
		print x_mm*y_mm/100, 'cm^2'