pseudofish

py2app provides a few more things than just packaging up the code into a bundle. To make the app more of a first class citizen in the Apple world, I’m going to add nice things like an icon, an About box and a proper name.

Apple provides quite a nice way of specifying all of this information in a .plist file and py2app is quite happy to make use of it. As the example, I’m going to take the list of birthdays made in parts 1 and 2 and improve it without changing the code, well not too much.

First step is to let py2app know where to find our .plist file. This involves a change to setup.py by creating an options entry to give the name of the .plist file:

setup(
  data_files=['English.lproj'],
  app=['main.py'],
  options=dict(py2app=dict(plist='Info.plist')))

Everything else is accomplished by adding in entries to the Info.plist file. According to the Mac OS X ‘Runtime Configuration: Guidelines For Configuring Applications‘ guide, there are a bunch of keys that need to be set as a minimum. I’m going to go through each key and what they actually do for your app.

To give my application a name, other than main.app, it is a matter of setting the CFBundleName property in the Info.plist file. There is a bit of boilerplate required which does nice XML things about specifying schemas and encodings. I’ve also added the package type in for now, with APPL representing an Application.

<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE plist PUBLIC '-//Apple Computer//DTD PLIST 1.0//EN''http://www.apple.com/DTDs/PropertyList-1.0.dtd'>
<plist version='1.0'>
  <dict>
    <!-- Used by py2app to generate application bundle -->
    <key>CFBundleName</key>
    <string>Date List</string>
    <!-- Package type is an Application -->
    <key>CFBundlePackageType</key>
    <string>APPL</string>
  </dict>
</plist>

At this point, building the application will result in the name of the application bundle being set correctly. Additionally, the application name will appear in the menu bar and in the About box. If you do a Get Info on the application bundle, it also shows up as an Application.

There are some other fields that Mac OS X will set for you in the About box if you fill in the appropriate properties. For example:

<!-- Version number - appears in About box -->
<key>CFBundleShortVersionString</key>
<string>1.2</string>
<!-- Build number - appears in About box -->
<key>CFBundleVersion</key>
<string>12</string>
<!-- Copyright notice - apears in About box -->
<key>NSHumanReadableCopyright</key>
<string>© Geoff Wilson 2005</string>

The About box is looking pretty good at this point, but for one key thing. That default icon simply has to go. Fortunately, it is as simple as specifying the appropriate property, and putting the icon file in the English.lproj directory.

<key>CFBundleIconFile</key>
<string>DateList</string>

All well and good, but I had absolutely no idea how to create an icon for Mac OS X. I’d gone through enough pain trying to get the favicon working for this site. Mac OS X icons looked much tricker. Fortunately, Mac OS X comes with its own tool for building icons, called Icon Composer. It lives under /Developer/Applications/Utilities

Icon development is something that you should take some time to consider for a real application. There is a good article at the O’Reilly site, and also some information from Apple. The short version is to drag an image into Icon Composer and save the results.

The icon file will be saved with an .icns extension, but there doesn’t seem to be a need to worry about that in the property file. In the interests of avoiding graphic design for a minute, I used the banner image from this site. This has the downside of making a solid square, but it means I can avoid Photoshop for a bit longer.

After re-building the application (to copy the icon file to the bundle), my icon turns up in all sorts of useful places like the About box, the Dock and the Finder.

There are a few more properties that are required to be set in the property file. The CFBundleIdentifier property is used to uniquely identify your application. The remaining properties, I’m not too sure as to where they are used, but they seem obvious enough to set values for. English is my development environment and the executable and bundle display name are set to the bundle name so that everything matches.

<!-- Globally unique identifier -->
<key>CFBundleIdentifier</key>
<string>com.pseudofish.DateList</string>
<key>CFBundleDevelopmentRegion</key>
<string>English</string>
<key>CFBundleExecutable</key>
<string>Date List</string>
<key>CFBundleDisplayName</key>
<string>Date List</string>

The complete Info.plist is included with the updated example. Now replete with a proper name, dock icon and an About box.