Bug correction in color.py

Computed value could be outside range [0, 255]. Now, it won't.

color.py

+#!/bin/env python
+
+import serial
+import pygame
+
+ser = serial.Serial("/dev/ttyACM0", 115200)
+pygame.init()
+
+size = width, height = 640, 480
+screen = pygame.display.set_mode(size)
+screen.fill((0, 0, 0))
+
+try:
+    ser.open()
+except Exception:
+    print("Error while opening serial port.")
+
+if ser.isOpen():
+    try:
+        ser.flushInput()
+        ser.flushOutput()
+
+        maximum = -1
+        minimum = -1
+
+        print("Calibration :")
+        pygame.display.flip()
+
+        for i in range(50) :
+            line = float(ser.readline())
+
+            if line < minimum or minimum < 0:
+                minimum = line
+                if line > maximum:
+                    maximum = line
+
+        print("Go :")
+        while True:
+            line = float(ser.readline())
+            valueR = int(255*(line-minimum)/(maximum-minimum))
+            if valueR < 0:
+                valueR = 0
+            if valueR > 255:
+                valueR = 255
+
+            screen.fill((valueR, 0, 0))
+            pygame.display.flip()
+
+        ser.close()
+    except Exception:
+        print("Error while fetching data from serial.")

main.py

-#!/bin/env python
-
-import serial
-import pygame
-
-ser = serial.Serial("/dev/ttyACM0", 115200)
-pygame.init()
-
-size = width, height = 640, 480
-black = 0, 0, 0
-screen = pygame.display.set_mode(size)
-background = pygame.Surface(screen.get_size())
-background = background.convert()
-background.fill(black)
-
-try:
-    ser.open()
-except Exception, e:
-    print("Error while opening serial port : "+str(e))
-
-if ser.isOpen():
-    ser.flushInput()
-    ser.flushOutput()
-
-    maximum = -1.
-    minimum = -1.
-    print("Calibration")
-    screen.blit(background, (0,0))
-    pygame.display.flip()
-    for i in range(50) :
-        line = float(ser.readline())
-	
-	if line < minimum or minimum < 0:
-		minimum = line
-	if line > maximum:
-		maximum = line
-
-    print("Go")
-    while True:
-	line = float(ser.readline())
-	background.fill((int(255.*(line-minimum)/(maximum-minimum)), 0, 0))
-	screen.blit(background, (0,0))
-	pygame.display.flip()
-
-    ser.close()