diff --git a/check_bento_build.py b/check_bento_build.py
index 34b2272a..1b069056 100644
--- a/check_bento_build.py
+++ b/check_bento_build.py
@@ -62,12 +62,12 @@ def remove_common_extensions(cy_bento, cy_setup):
 
 def print_results(cy_bento, cy_setup):
     def info(text):
-        print
+        print('')
         print(text)
         print('-' * len(text))
 
     if not (cy_bento or cy_setup):
-        print "bento.info and setup.py files match."
+        print("bento.info and setup.py files match.")
 
     if cy_bento:
         info("Extensions found in 'bento.info' but not in any 'setup.py:")
@@ -80,8 +80,8 @@ def print_results(cy_bento, cy_setup):
         info("Consider adding the following to the 'bento.info' Library:")
         for dir_path in cy_setup:
             module_path = dir_path.replace('/', '.')
-            print BENTO_TEMPLATE.format(module_path=module_path,
-                                        dir_path=dir_path)
+            print(BENTO_TEMPLATE.format(module_path=module_path,
+                                        dir_path=dir_path))
 
 
 if __name__ == '__main__':
diff --git a/doc/ext/plot2rst.py b/doc/ext/plot2rst.py
index 00560be4..3b26aeb9 100644
--- a/doc/ext/plot2rst.py
+++ b/doc/ext/plot2rst.py
@@ -187,7 +187,7 @@ def generate_example_galleries(app):
 def generate_examples_and_gallery(example_dir, rst_dir, cfg):
     """Generate rst from examples and create gallery to showcase examples."""
     if not example_dir.exists:
-        print "No example directory found at", example_dir
+        print("No example directory found at", example_dir)
         return
     rst_dir.makedirs()
 
@@ -225,12 +225,12 @@ def write_gallery(gallery_index, src_dir, rst_dir, cfg, depth=0):
     index_name = cfg.plot2rst_index_name + cfg.source_suffix
     gallery_template = src_dir.pjoin(index_name)
     if not os.path.exists(gallery_template):
-        print src_dir
-        print 80*'_'
-        print ('Example directory %s does not have a %s file'
+        print(src_dir)
+        print(80*'_')
+        print('Example directory %s does not have a %s file'
                         % (src_dir, index_name))
-        print 'Skipping this directory'
-        print 80*'_'
+        print('Skipping this directory')
+        print(80*'_')
         return
 
     gallery_description = file(gallery_template).read()
@@ -252,11 +252,11 @@ def write_gallery(gallery_index, src_dir, rst_dir, cfg, depth=0):
         try:
             write_example(src_name, src_dir, rst_dir, cfg)
         except Exception:
-            print "Exception raised while running:"
-            print "%s in %s" % (src_name, src_dir)
-            print '~' * 60
+            print("Exception raised while running:")
+            print("%s in %s" % (src_name, src_dir))
+            print('~' * 60)
             traceback.print_exc()
-            print '~' * 60
+            print('~' * 60)
             continue
 
         link_name = sub_dir.pjoin(src_name)
@@ -354,8 +354,8 @@ def write_example(src_name, src_dir, rst_dir, cfg):
 
     if not thumb_path.exists:
         if cfg.plot2rst_default_thumb is None:
-            print "WARNING: No plots found and default thumbnail not defined."
-            print "Specify 'plot2rst_default_thumb' in Sphinx config file."
+            print("WARNING: No plots found and default thumbnail not defined.")
+            print("Specify 'plot2rst_default_thumb' in Sphinx config file.")
         else:
             shutil.copy(cfg.plot2rst_default_thumb, thumb_path)
 
diff --git a/doc/gh-pages.py b/doc/gh-pages.py
index ab29959e..dd798c02 100644
--- a/doc/gh-pages.py
+++ b/doc/gh-pages.py
@@ -48,7 +48,7 @@ def sh2(cmd):
     out = p.communicate()[0]
     retcode = p.returncode
     if retcode:
-        print out.rstrip()
+        print(out.rstrip())
         raise CalledProcessError(retcode, cmd)
     else:
         return out.rstrip()
@@ -123,12 +123,12 @@ if __name__ == '__main__':
         sh('git add %s' % tag)
         sh2('git commit -m"Updated doc release: %s"' % tag)
 
-        print 'Most recent commit:'
+        print('Most recent commit:')
         sys.stdout.flush()
         sh('git --no-pager log --oneline HEAD~1..')
     finally:
         cd(startdir)
 
-    print
-    print 'Now verify the build in: %r' % dest
-    print "If everything looks good, run 'git push' inside doc/gh-pages."
+    print('')
+    print('Now verify the build in: %r' % dest)
+    print("If everything looks good, run 'git push' inside doc/gh-pages.")
diff --git a/doc/logo/scikit_image_logo.py b/doc/logo/scikit_image_logo.py
index fc8ec006..014c5786 100644
--- a/doc/logo/scikit_image_logo.py
+++ b/doc/logo/scikit_image_logo.py
@@ -8,7 +8,7 @@ Original snake image from pixabay [1]_
 """
 import sys
 if len(sys.argv) != 2 or sys.argv[1] != '--no-plot':
-    print "Run with '--no-plot' flag to generate logo silently."
+    print("Run with '--no-plot' flag to generate logo silently.")
 else:
     import matplotlib as mpl
     mpl.use('Agg')
diff --git a/doc/source/coverage_generator.py b/doc/source/coverage_generator.py
index 83fd5d86..1112c021 100755
--- a/doc/source/coverage_generator.py
+++ b/doc/source/coverage_generator.py
@@ -49,13 +49,13 @@ def calculate_coverage(reader):
               partial_items,
               total_items - (partial_items + done_items + na_items),
               na_items)
-    
+
     return list(i / total_items for i in counts)
 
 def read_table_titles(reader):
     r"""Create a dictionary with keys as section names and values as a list of
     table names
-    
+
     return (dict)
     """
     section_titles = []
@@ -69,39 +69,39 @@ def read_table_titles(reader):
             # Extract names of the tables
             for name in row[1:]:
                 if len(name) > 0:
-                    names.append(name) 
+                    names.append(name)
                 else:
                     break
             section_titles.append(row[0])
             table_names[row[0]] = names
     except csv.Error, e:
         sys.exit('line %d: %s' % (reader.line_num, e))
-    
+
     return section_titles,table_names
 
 def table_seperator(stream,lengths,character="-"):
     r"""Write out table row seperator
-    
+
     :Input:
      - *stream* (io/stream) Stream where output is put
      - *lengths* (list) A list of the lengths of the columns
      - *character* (string) Character to be filled between +, defaults to "-".
-     
+
     """
     stream.write("+")
     stream.write('+'.join([character*(length+2) for length in lengths]))
     stream.write("+")
-    
+
 def table_row(stream,data,lengths,num_columns=None):
     r"""Write out table row data
-    
+
     :Input:
      - *stream* (io/stream) Stream where output is put
      - *data* (list) List of strings containing data
      - *lengths* (list) A list of the lengths of the columns
-     - *num_columns* (string) Number of columns, defaults to the length of the 
+     - *num_columns* (string) Number of columns, defaults to the length of the
        data array
-     
+
     """
     if num_columns is None:
         num_columns = len(data)
@@ -115,11 +115,11 @@ def table_row(stream,data,lengths,num_columns=None):
         else:
             entry = MISSING_STRING
         stream.write(" " + entry + " "*(lengths[i] - len(entry)) + " |")
-    
+
 def generate_table(reader,stream,table_name=None,
                     column_titles=["Functionality","Matlab","Scipy","Scipy"]):
     r"""Generate a reST grid table based on the CSV data in reader
-    
+
     Reads CSV data from *reader* until an empty line is found and generates a
     reST table based on the data into *stream*.  A table name can be given for
     a section and table label.  All rows are read in and checked for maximum
@@ -127,13 +127,13 @@ def generate_table(reader,stream,table_name=None,
     widths so that the table can be constructed.  If a row contains less than
     the maximum number of columns a string is inserted that defaults to the
     string *MISSING_STRING* which is a global parameter.
-    
+
     :Input:
      - reader (csv.reader) The CSV reader to read in from
      - stream (iostream) Output target
      - table_name (string) Optional name of table, defaults to *None*
      - column_titles (list) List of column titles
-     
+
     """
     # Find number of columns and column widths, base number of columns is
     # determined by the headers
@@ -141,7 +141,6 @@ def generate_table(reader,stream,table_name=None,
     data = [column_titles]
     try:
         for row in reader:
-            # print row
             if len(row[0]) == 0:
                 break
             data.append([entry.expandtabs() for entry in row])
@@ -153,7 +152,7 @@ def generate_table(reader,stream,table_name=None,
     for row in data:
         for i in xrange(len(row)):
             column_lengths[i] = max(column_lengths[i],len(row[i]))
-    
+
     # Output table header
     stream.write(table_name + "\n")
     if table_name is not None:
@@ -167,7 +166,7 @@ def generate_table(reader,stream,table_name=None,
     stream.write("\n")
     table_seperator(stream,column_lengths,character="=")
     stream.write("\n")
-    
+
     # Output table data
     for row in data[1:]:
         table_row(stream,row,column_lengths,num_columns)
@@ -175,28 +174,28 @@ def generate_table(reader,stream,table_name=None,
         table_seperator(stream,column_lengths,character='-')
         stream.write("\n")
     stream.write("\n\n")
-    
+
 def generate_page(csv_path,stream,page_title="Coverage Tables"):
     r"""Generate coverage table page
-    
+
     Generates all reST for all tables contained in the CSV file at *csv_path*
     and output it to *stream*.
-    
+
     :Input:
      - *csv_path* (path) Path to CSV file
      - *stream* (iostream) Output stream
-     - *page_title* (string) Optional page title, defaults to 
+     - *page_title* (string) Optional page title, defaults to
        ``Coverage Tables``.
     """
     # Open reader
     csv_file = open(csv_path,'U')
-    
+
     # Sniffer does not seem to work all the time even when an Excel
     # spread sheet is being used
     # dialect = csv.Sniffer().sniff(csv_file.read(1024))
     # csv_file.seek(0)
     # reader = csv.reader(csv_file, dialect)
-    
+
     reader = csv.reader(csv_file)
     item_counts = calculate_coverage(reader)
     csv_file.seek(0)
@@ -254,21 +253,21 @@ if __name__ == "__main__":
     output_path = './coverage_table.txt'
     if len(sys.argv) > 1:
         if sys.argv[1][:5].lower() == "help":
-            print "Coverage Table Generator: coverage_generator.py"
-            print "  Usage: coverage_generator.py [csv] [output]"
-            print "    csv - Path to csv file, defaults to ./coverage.csv"
-            print "    output - Ouput path, defaults to ./coverage_table.txt"
-            print ""
+            print("Coverage Table Generator: coverage_generator.py")
+            print("  Usage: coverage_generator.py [csv] [output]")
+            print("    csv - Path to csv file, defaults to ./coverage.csv")
+            print("    output - Ouput path, defaults to ./coverage_table.txt")
+            print('')
             sys.exit(0)
         if len(sys.argv) == 2:
             csv_path = os.path.abspath(sys.argv[1])
         if len(sys.argv) == 3:
             output_path = os.path.abspath(sys.argv[2])
-    
+
     output = open(output_path,'w')
     generate_page(csv_path,output)
     output.close()
-    
+
     print("Generated %s from %s." % (output_path,csv_path))
 
 
diff --git a/doc/source/user_guide/data_types.txt b/doc/source/user_guide/data_types.txt
index c3b87b2e..43ea8e9b 100644
--- a/doc/source/user_guide/data_types.txt
+++ b/doc/source/user_guide/data_types.txt
@@ -34,9 +34,9 @@ violates these assumptions about the dtype range::
 
    >>> from skimage import img_as_float
    >>> image = np.arange(0, 50, 10, dtype=np.uint8)
-   >>> print image.astype(np.float) # These float values are out of range.
+   >>> print(image.astype(np.float)) # These float values are out of range.
    [  0.  10.  20.  30.  40.]
-   >>> print img_as_float(image)
+   >>> print(img_as_float(image))
    [ 0.          0.03921569  0.07843137  0.11764706  0.15686275]
 
 
diff --git a/doc/tools/apigen.py b/doc/tools/apigen.py
index 49c7e6e3..f1a94b6a 100644
--- a/doc/tools/apigen.py
+++ b/doc/tools/apigen.py
@@ -176,7 +176,7 @@ class ApiDocWriter(object):
         ''' Parse module defined in *uri* '''
         filename = self._uri2path(uri)
         if filename is None:
-            print filename, 'erk'
+            print(filename, 'erk')
             # nothing that we could handle here.
             return ([],[])
         f = open(filename, 'rt')
@@ -260,7 +260,7 @@ class ApiDocWriter(object):
         # get the names of all classes and functions
         functions, classes = self._parse_module_with_import(uri)
         if not len(functions) and not len(classes) and DEBUG:
-            print 'WARNING: Empty -', uri  # dbg
+            print('WARNING: Empty -', uri)  # dbg
             return ''
 
         # Make a shorter version of the uri that omits the package name for
@@ -449,7 +449,7 @@ class ApiDocWriter(object):
             relpath = (outdir + os.path.sep).replace(relative_to + os.path.sep, '')
         else:
             relpath = outdir
-        print "outdir: ", relpath
+        print("outdir: ", relpath)
         idx = open(path,'wt')
         w = idx.write
         w('.. AUTO-GENERATED FILE -- DO NOT EDIT!\n\n')
diff --git a/doc/tools/build_modref_templates.py b/doc/tools/build_modref_templates.py
index 8dfc6124..c51c590a 100644
--- a/doc/tools/build_modref_templates.py
+++ b/doc/tools/build_modref_templates.py
@@ -13,7 +13,7 @@ from distutils.version import LooseVersion as V
 #*****************************************************************************
 
 def abort(error):
-    print '*WARNING* API documentation not generated: %s'%error
+    print('*WARNING* API documentation not generated: %s' % error)
     exit()
 
 if __name__ == '__main__':
@@ -54,4 +54,4 @@ if __name__ == '__main__':
                                         ]
     docwriter.write_api_docs(outdir)
     docwriter.write_index(outdir, 'api', relative_to='source/api')
-    print '%d files written' % len(docwriter.written_modules)
+    print('%d files written' % len(docwriter.written_modules))
diff --git a/doc/tools/plot_pr.py b/doc/tools/plot_pr.py
index 09a9f91e..08f4fc0e 100644
--- a/doc/tools/plot_pr.py
+++ b/doc/tools/plot_pr.py
@@ -48,7 +48,7 @@ def fetch_PRs(user='scikit-image', repo='scikit-image', state='open'):
 
         fetch_status = 'Fetching page %(page)d (state=%(state)s)' % params + \
                        ' from %(user)s/%(repo)s...' % config
-        print fetch_status
+        print(fetch_status)
 
         f = urllib.urlopen(
             'https://api.github.com/repos/%(user)s/%(repo)s/pulls?%(params)s' \
@@ -61,7 +61,7 @@ def fetch_PRs(user='scikit-image', repo='scikit-image', state='open'):
 
         if 'message' in page_data and page_data['message'] == "Not Found":
             page_data = []
-            print 'Warning: Repo not found (%(user)s/%(repo)s)' % config
+            print('Warning: Repo not found (%(user)s/%(repo)s)' % config)
         else:
             data.extend(page_data)
 
@@ -69,7 +69,7 @@ def fetch_PRs(user='scikit-image', repo='scikit-image', state='open'):
 
 try:
     PRs = json.loads(open(cache, 'r').read())
-    print 'Loaded PRs from cache...'
+    print('Loaded PRs from cache...')
 
 except IOError:
     PRs = fetch_PRs(user='stefanv', repo='scikits.image', state='closed')
@@ -81,7 +81,7 @@ except IOError:
     cf.flush()
 
 nrs = [pr['number'] for pr in PRs]
-print 'Processing %d pull requests...' % len(nrs)
+print('Processing %d pull requests...' % len(nrs))
 
 dates = [dateutil.parser.parse(pr['created_at']) for pr in PRs]
 
diff --git a/skimage/feature/template.py b/skimage/feature/template.py
index 51ca90b4..5cb4d382 100644
--- a/skimage/feature/template.py
+++ b/skimage/feature/template.py
@@ -34,14 +34,14 @@ def match_template(image, template, pad_input=False):
     --------
     >>> template = np.zeros((3, 3))
     >>> template[1, 1] = 1
-    >>> print template
+    >>> print(template)
     [[ 0.  0.  0.]
      [ 0.  1.  0.]
      [ 0.  0.  0.]]
     >>> image = np.zeros((6, 6))
     >>> image[1, 1] = 1
     >>> image[4, 4] = -1
-    >>> print image
+    >>> print(image)
     [[ 0.  0.  0.  0.  0.  0.]
      [ 0.  1.  0.  0.  0.  0.]
      [ 0.  0.  0.  0.  0.  0.]
@@ -49,13 +49,13 @@ def match_template(image, template, pad_input=False):
      [ 0.  0.  0.  0. -1.  0.]
      [ 0.  0.  0.  0.  0.  0.]]
     >>> result = match_template(image, template)
-    >>> print np.round(result, 3)
+    >>> print(np.round(result, 3))
     [[ 1.    -0.125  0.     0.   ]
      [-0.125 -0.125  0.     0.   ]
      [ 0.     0.     0.125  0.125]
      [ 0.     0.     0.125 -1.   ]]
     >>> result = match_template(image, template, pad_input=True)
-    >>> print np.round(result, 3)
+    >>> print(np.round(result, 3))
     [[-0.125 -0.125 -0.125  0.     0.     0.   ]
      [-0.125  1.    -0.125  0.     0.     0.   ]
      [-0.125 -0.125 -0.125  0.     0.     0.   ]
diff --git a/skimage/io/_plugins/gtk_plugin.py b/skimage/io/_plugins/gtk_plugin.py
index 39cd9a27..961aaa0a 100644
--- a/skimage/io/_plugins/gtk_plugin.py
+++ b/skimage/io/_plugins/gtk_plugin.py
@@ -6,13 +6,13 @@ try:
     # gui's pyos_inputhook.
     window_manager.acquire('gtk')
 except GuiLockError, gle:
-    print gle
+    print(gle)
 else:
     try:
         import gtk
     except ImportError:
-        print 'pygtk libraries not installed.'
-        print 'plugin not loaded.'
+        print('pygtk libraries not installed.')
+        print('plugin not loaded.')
         window_manager._release('gtk')
     else:
 
@@ -51,4 +51,4 @@ else:
                 window_manager.register_callback(gtk.main_quit)
                 gtk.main()
             else:
-                print 'no images to display'
+                print('no images to display')
diff --git a/skimage/io/_plugins/plugin.py b/skimage/io/_plugins/plugin.py
index da69363d..08d0e2d9 100644
--- a/skimage/io/_plugins/plugin.py
+++ b/skimage/io/_plugins/plugin.py
@@ -52,8 +52,8 @@ def _scan_plugins():
 
         for p in provides:
             if not p in plugin_store:
-                print "Plugin `%s` wants to provide non-existent `%s`." \
-                      " Ignoring." % (name, p)
+                print("Plugin `%s` wants to provide non-existent `%s`." \
+                      " Ignoring." % (name, p))
 
         plugin_provides[name] = valid_provides
         plugin_module_name[name] = os.path.basename(f)[:-4]
@@ -208,8 +208,8 @@ def _load(plugin):
     provides = plugin_provides[plugin]
     for p in provides:
         if not hasattr(plugin_module, p):
-            print "Plugin %s does not provide %s as advertised.  Ignoring." % \
-                  (plugin, p)
+            print("Plugin %s does not provide %s as advertised.  Ignoring." % \
+                  (plugin, p))
         else:
             store = plugin_store[p]
             func = getattr(plugin_module, p)
diff --git a/skimage/io/_plugins/qt_plugin.py b/skimage/io/_plugins/qt_plugin.py
index 24cf472c..db4cb4cc 100644
--- a/skimage/io/_plugins/qt_plugin.py
+++ b/skimage/io/_plugins/qt_plugin.py
@@ -144,7 +144,7 @@ def _app_show():
     if app and window_manager.has_windows():
         app.exec_()
     else:
-        print 'No images to show.  See `imshow`.'
+        print('No images to show.  See `imshow`.')
 
 
 def imsave(filename, img, format_str=None):
diff --git a/skimage/io/_plugins/util.py b/skimage/io/_plugins/util.py
index ed547222..98dd4f87 100644
--- a/skimage/io/_plugins/util.py
+++ b/skimage/io/_plugins/util.py
@@ -76,8 +76,8 @@ class WindowManager(object):
         try:
             self._windows.remove(win)
         except ValueError:
-            print 'Unable to find referenced window in tracked windows.'
-            print 'Ignoring...'
+            print('Unable to find referenced window in tracked windows.')
+            print('Ignoring...')
         else:
             if len(self._windows) == 0:
                 self._exec_callback()
diff --git a/skimage/io/collection.py b/skimage/io/collection.py
index 6aa9cfc6..7c3f739b 100644
--- a/skimage/io/collection.py
+++ b/skimage/io/collection.py
@@ -98,7 +98,7 @@ class MultiImage(object):
     >>> len(img)
     2
     >>> for frame in img:
-    ...     print frame.shape
+    ...     print(frame.shape)
     (15, 10)
     (15, 10)
 
diff --git a/skimage/morphology/ccomp.pyx b/skimage/morphology/ccomp.pyx
index 27318363..91e2611c 100644
--- a/skimage/morphology/ccomp.pyx
+++ b/skimage/morphology/ccomp.pyx
@@ -118,17 +118,17 @@ def label(input, DTYPE_t neighbors=8, DTYPE_t background=-1, return_num=False):
     Examples
     --------
     >>> x = np.eye(3).astype(int)
-    >>> print x
+    >>> print(x)
     [[1 0 0]
      [0 1 0]
      [0 0 1]]
 
-    >>> print m.label(x, neighbors=4)
+    >>> print(m.label(x, neighbors=4))
     [[0 1 1]
      [2 3 1]
      [2 2 4]]
 
-    >>> print m.label(x, neighbors=8)
+    >>> print(m.label(x, neighbors=8))
     [[0 1 1]
      [1 0 1]
      [1 1 0]]
@@ -137,7 +137,7 @@ def label(input, DTYPE_t neighbors=8, DTYPE_t background=-1, return_num=False):
     ...               [1, 1, 5],
     ...               [0, 0, 0]])
 
-    >>> print m.label(x, background=0)
+    >>> print(m.label(x, background=0))
     [[ 0 -1 -1]
      [ 0  0  1]
      [-1 -1 -1]]
diff --git a/skimage/scripts/skivi.py b/skimage/scripts/skivi.py
index 2e907bbe..7b7b5aeb 100644
--- a/skimage/scripts/skivi.py
+++ b/skimage/scripts/skivi.py
@@ -6,7 +6,7 @@ def main():
     import sys
 
     if len(sys.argv) != 2:
-        print "Usage: skivi <image-file>"
+        print("Usage: skivi <image-file>")
         sys.exit(-1)
 
     io.use_plugin('qt')
diff --git a/skimage/util/montage.py b/skimage/util/montage.py
index 587c0939..df3ad12e 100644
--- a/skimage/util/montage.py
+++ b/skimage/util/montage.py
@@ -50,7 +50,7 @@ def montage2d(arr_in, fill='mean', rescale_intensity=False):
     >>> import numpy as np
     >>> from skimage.util.montage import montage2d
     >>> arr_in = np.arange(3 * 2 * 2).reshape(3, 2, 2)
-    >>> print arr_in  # doctest: +NORMALIZE_WHITESPACE
+    >>> print(arr_in)  # doctest: +NORMALIZE_WHITESPACE
     [[[ 0  1]
       [ 2  3]]
      [[ 4  5]
@@ -58,20 +58,20 @@ def montage2d(arr_in, fill='mean', rescale_intensity=False):
      [[ 8  9]
       [10 11]]]
     >>> arr_out = montage2d(arr_in)
-    >>> print arr_out.shape
+    >>> print(arr_out.shape)
     (4, 4)
-    >>> print arr_out
+    >>> print(arr_out)
     [[  0.    1.    4.    5. ]
      [  2.    3.    6.    7. ]
      [  8.    9.    5.5   5.5]
      [ 10.   11.    5.5   5.5]]
-    >>> print arr_in.mean()
+    >>> print(arr_in.mean())
     5.5
     """
     assert arr_in.ndim == 3
 
     n_images, height, width = arr_in.shape
-    
+
     arr_in = arr_in.copy()
 
     # -- rescale intensity if necessary
diff --git a/skimage/viewer/canvastools/linetool.py b/skimage/viewer/canvastools/linetool.py
index 7cdf91b5..7a459401 100644
--- a/skimage/viewer/canvastools/linetool.py
+++ b/skimage/viewer/canvastools/linetool.py
@@ -60,7 +60,7 @@ class LineTool(CanvasToolBase):
         if on_enter is None:
             def on_enter(pts):
                 x, y = np.transpose(pts)
-                print "length = %0.2f" % np.sqrt(np.diff(x)**2 + np.diff(y)**2)
+                print("length = %0.2f" % np.sqrt(np.diff(x)**2 + np.diff(y)**2))
         self.callback_on_enter = on_enter
 
         self.connect_event('button_press_event', self.on_mouse_press)