Add Max's error checks!

Author: bnmnetp

image.py

@@ -48,7 +48,7 @@
 # Added _imroot.lift() to ensure that pictures aren't hidden under other Windows
 # (needed on Windows 7 & Python 3.4. Ubuntu 14.04 was fine without it).
 #
-# version 1.4 
+# version 1.4
 # Brad Miller
 # distribute on pypi
 #
@@ -65,6 +65,18 @@
 #   Force the Pixel object to store all rgb values as int's, to avoid students getting errors when
 #       they divide in their image manipulation calculations
 #   Make EmptyImage's show up with white backgrounds, for both PIL and tkinter
+# Version 1.5 May 2016 Max Hailperin <[email protected]>
+# Changes:
+#   Add more checks of parameter types and ranges so error messages are
+#     closer to the user's code and more intelligible.
+#   Disable the ability of Pixels to range up to 1.0 instead of 255, which
+#     didn't seem used and would make the type checking more complex.
+#
+# Version 1.6 May 2016 Max Hailperin <[email protected]>
+# Changes:
+#   Add autoShow function that can be used to get and optionally set a flag
+#     that if True makes images automatically be displayed when their printed
+#     representation is produced (e.g. as results in the shell).
 
 try:
     import tkinter
@@ -95,6 +107,17 @@
 #_imroot.after_idle(_imroot.call, 'wm', 'attributes', '.', '-topmost', False)
 
 
+# For backward compatibility, the new autoShow feature is off by default:
+autoShowOn = False
+
+def autoShow(newSetting=None):
+    """Return and optionally change the True/False autoShow setting"""
+    global autoShowOn
+    oldSetting = autoShowOn
+    if newSetting != None:
+        autoShowOn = newSetting
+    return oldSetting
+
 def formatPixel(data):
     if type(data) == tuple:
         return '{#%02x%02x%02x}'%data
@@ -175,10 +198,10 @@ class Pixel(object):
     """This simple class abstracts the RGB pixel values."""
     def __init__(self, red, green, blue):
         super(Pixel, self).__init__()
-        self.__red = red
-        self.__green = green
-        self.__blue = blue
         self.max = 255
+        self.setRed(red)
+        self.setGreen(green)
+        self.setBlue(blue)
 
     def getRed(self):
         """Return the red component of the pixel"""
@@ -210,8 +233,10 @@ def get_color_tuple(self):
 
     def setRed(self,red):
         """Modify the red component"""
-        if self.max >= red >= 0:
-            self.__red = int(red)
+        if not isinstance(red, int):
+            raise TypeError("Error:  pixel value %r is not an integer" % red)
+        elif self.max >= red >= 0:
+            self.__red = red
         else:
             raise ValueError("Error:  pixel value %d is out of range" % red)
 
@@ -220,8 +245,10 @@ def set_red(self, red):
 
     def setGreen(self,green):
         """Modify the green component"""
-        if self.max >= green >= 0:
-            self.__green = int(green)
+        if not isinstance(green, int):
+            raise TypeError("Error:  pixel value %r is not an integer" % green)
+        elif self.max >= green >= 0:
+            self.__green = green
         else:
             raise ValueError("Error:  pixel value %d is out of range" % green)
 
@@ -230,8 +257,10 @@ def set_green(self, green):
 
     def setBlue(self,blue):
         """Modify the blue component"""
-        if self.max >= blue >= 0:
-            self.__blue = int(blue)
+        if not isinstance(blue, int):
+            raise TypeError("Error:  pixel value %r is not an integer" % blue)
+        elif self.max >= blue >= 0:
+            self.__blue = blue
         else:
             raise ValueError("Error:  pixel value %d is out of range" % blue)
 
@@ -258,6 +287,10 @@ def __getitem__(self,key):
     def setRange(self,pmax):
         """docstring for setRange"""
         if pmax == 1.0:
+            raise ValueError("Range of 1.0 is not currently supported")
+            # This raising of an error was inserted  in conjunction with
+            # requiring the values to be integers, which is necessary for
+            # formatPixel to work correctly. Was 1.0 ever used?
             self.max = 1.0
         elif pmax == 255:
             self.max = 255
@@ -513,19 +546,40 @@ def toList(self):
     def to_list(self):
         return self.toList()
 
+    def __repr__(self):
+        r = super(AbstractImage, self).__repr__()
+        if autoShowOn:
+            w = ImageWin(r, self.width, self.height)
+            self.draw(w)
+        return r
+
+
 class FileImage(AbstractImage):
     def __init__(self,thefile):
+        if not isinstance(thefile, str):
+            raise TypeError("Error: file name %r not a string" % thefile)
         super(FileImage, self).__init__(fname = thefile)
 
 class Image(FileImage):
         pass
 
 class EmptyImage(AbstractImage):
     def __init__(self,cols,rows):
+        if not isinstance(cols, int):
+            raise TypeError("Error: width %r not an integer" % cols)
+        if cols <= 0:
+            raise ValueError("Error: width %d not positive" % cols)
+        if not isinstance(rows, int):
+            raise TypeError("Error: height %r not an integer" % rows)
+        if rows <= 0:
+            raise ValueError("Error: height %d not positive" % rows)
         super(EmptyImage, self).__init__(height = rows, width = cols)
 
 class ListImage(AbstractImage):
     def __init__(self,thelist):
+        # Note that the corresponding code in AbstractImage doesn't work
+        # so apparently ListImage isn't used. As such, there doesn't seem
+        # to be much point in adding error checking.
         super(ListImage, self).__init__(data=thelist)
 
 # Example program  Read in an image and calulate the negative.

setup.py

@@ -6,7 +6,7 @@
 setup(
     name='cImage',
     description='Image manipulation library for media computation education',
-    version='2.0.0',
+    version='2.0.1',
     py_modules = ['image'],
     author = 'Brad Miller and Dan Schellenberg',
     author_email = '[email protected]',