pycalc_units.py

#!/usr/bin/env python

# Python calculator for conversion to SI units

import pygame
from math import *

BACKGROUND = 255, 255, 255
BORDER = 2
RES = 600,495           # initial window size
HSIZE, VSIZE = 6, 9     # button grid dimension (top row is for display)
MAXLEN = 100            # maximum digits

# font name
fn = "fsex2.ttf"

us_units = (
("_floz", "*0.0295735295625"),  # l
("_pt",   "*0.473176473"),      # l
("_qt",   "*0.946352946"),      # l
("_gal",  "*3.785411784"),      # l
("_nm",   "*1852"),             # m
("_in",   "*0.0254"),           # m
("_ft",   "*0.3048"),           # m
("_sqft", "*0.09290304"),       # m²
("_acre", "*4046.8564224"),     # m²
("_yd",   "*0.9144"),           # m
("_mi",   "*1609.344"),         # m
("_lb",   "*0.45359237"),       # kg
)

# button layout
bmap = """_in    _ft  _yd  _mi  **    C
          _gal   exp( sin( cos( tan(  log10(
          _pt    pi   abs( **2  sqrt( log(
          _qt    deg( SCI  (    )     /
          _floz  rad( 7    8    9     *
          _sqft  fah( 4    5    6     -
          _acre  cel( 1    2    3     +
          _nm    _lb  0    .    j     ="""

# color indices for buttons
col_ind = """333312
311111
311111
311114
315554
315554
315554
335554"""

col_ind = col_ind.splitlines()

# RGB colors for each color index
cols = (
(255, 255, 255),
(255,96,117),
(255,237,83),
(142,148,255),
(228,142,215),
(159,229,110),
)

# text colors and sizes
button_rgb  = 0, 0, 0
display_rgb = 0, 0, 0
size_button = 30
size_disp   = 55

but = []
for l in bmap.splitlines():
    bb = l.split()
    but.append(bb)

def deg(x):
    return degrees(x)

def rad(x):
    return radians(x)

def fah(x):
    # Celsius -> Fahrenheit
    return (x * 9/5) + 32

def cel(x):
    # Fahrenheit -> Celsius
    return (x - 32) * 5/9

class PyCalc:
    def __init__(self):
        pygame.init()
        self.res = RES
        self.screen = pygame.display.set_mode(self.res, pygame.RESIZABLE)
        pygame.display.set_caption('PyCalc (units)')
        self.screen.fill(BACKGROUND)
        self.font = pygame.font.Font(fn, size_button)
        self.fontres = pygame.font.Font(fn, size_disp)
        self.clock = pygame.time.Clock()
        self.inp = ""

    def events(self):
        global a, b

        for event in pygame.event.get():
            if event.type == pygame.QUIT: self.running = False
            if event.type == pygame.VIDEORESIZE:
                self.res = event.w, event.h
                self.last = 0
                self.screen = pygame.display.set_mode(self.res, pygame.RESIZABLE)
            if event.type == pygame.MOUSEBUTTONDOWN:
                x, y = pygame.mouse.get_pos()
                boxx, boxy = self.res[0] // HSIZE, self.res[1] // VSIZE
                X, Y = x // boxx, y // boxy
                if Y == 0 or Y > VSIZE - 1 or X > HSIZE - 1:
                    return
                ci = but[Y - 1][X]
                if ci == "=":       # evaluate expression
                    try:
                        inp2 = self.inp
                        for u1, u2 in us_units:
                            inp2 = inp2.replace(u1, u2)
                        self.inp = str(eval(inp2))
                        a = eval(self.inp)
                    except:
                        self.inp += " *ERROR*"
                elif ci == "C":     # clear screen
                    self.inp = ""
                elif ci == "SCI":   # convert to scientific notation
                    try:
                        self.inp = "%e" % float(self.inp)
                    except:
                        pass
                else:               # or add button text to input
                    self.inp += but[Y - 1][X]

    def run(self):
        self.running = True
        while self.running:
            self.clock.tick(10)
            self.events()
            self.update()
        pygame.quit()

    def update(self):
        self.screen.fill(BACKGROUND)
        boxx, boxy = self.res[0] // HSIZE, self.res[1] // VSIZE
        for y in range(1, VSIZE):
            for x in range(HSIZE):
                ci = int(col_ind[y - 1][x])
                pygame.draw.rect(self.screen, cols[ci],
                    [x * boxx + BORDER, y * boxy + BORDER,
                    boxx - 2 * BORDER, boxy - 2 * BORDER])
                t = but[y - 1][x]
                if t[-1] == "(" and t != "(":
                    t = t[:-1]
                if t != "#":
                    tr = self.font.render(t, True, button_rgb)
                    ox = max(0, (boxx - tr.get_width()) // 2)
                    oy = max(0, (boxy - tr.get_height()) // 2)
                    self.screen.blit(tr, (x * boxx + BORDER + ox, y * boxy + BORDER + oy))
        if len(self.inp) < MAXLEN:  # check if maximum digits exceeded
            t = self.inp
        else:
            try:
                self.inp = "%e" % float(self.inp)
                t = self.inp
            except:
                t = "*TOO LONG*"
        tr = self.fontres.render(t, True, display_rgb)
        self.screen.blit(tr, (0, 0))
        pygame.display.flip()

app = PyCalc()
app.run()