diff -r 7a45415956b9 Lib/idlelib/ZoomInOut.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Lib/idlelib/ZoomInOut.py	Tue Apr 30 03:41:03 2013 +0200
@@ -0,0 +1,39 @@
+# ZoomInOut extension
+# Press <Control-plus> to zoom in and <Control-minus> to zoom out
+
+
+def zoom_decorator(func):
+    """
+    Decotaror to avoid code duplication in
+    zoom_in_event and zoom_out_event
+    """
+    def f(self, event):
+        font = self.text.configure('font')[-1]
+        if isinstance(font, str):
+            font = self.text.tk.split(font)
+        fontname, fontsize, fontwidth = font
+        fontsize = func(self, int(fontsize))
+        self.text.configure(font=(fontname, fontsize, fontwidth))
+    return f
+
+
+class ZoomInOut:
+
+    menudefs = [
+        ('windows', [
+            ('Zoom In', '<<zoom-in>>'),
+            ('Zoom Out', '<<zoom-out>>')
+        ])
+    ]
+
+    def __init__(self, editwin):
+        self.text = editwin.text
+
+    @zoom_decorator
+    def zoom_in_event(self, fontsize):
+        return fontsize + 1 if fontsize < 22 else fontsize
+
+    @zoom_decorator
+    def zoom_out_event(self, fontsize):
+        return fontsize - 1 if fontsize > 7 else fontsize
+
diff -r 7a45415956b9 Lib/idlelib/config-extensions.def
--- a/Lib/idlelib/config-extensions.def	Sun Apr 28 17:07:16 2013 -0400
+++ b/Lib/idlelib/config-extensions.def	Tue Apr 30 03:41:03 2013 +0200
@@ -44,6 +44,12 @@
 [ZoomHeight_cfgBindings]
 zoom-height=<Alt-Key-2>
 
+[ZoomInOut]
+enable=1
+[ZoomInOut_cfgBindings]
+zoom-in=<Control-plus>
+zoom-out=<Control-minus>
+
 [ScriptBinding]
 enable=1
 enable_shell=0