Metro Firefox without Windows 8

A few weeks ago I started working on the Firefox "Metro UI" project, for Windows 8's Metro (or Modern) touch-screen environment. While we're still working on getting our first preview builds ready for Windows 8 users to try out, you can already check out the current source code from the elm branch and build it yourself if you want to get involved and help us fix some bugs.

What you might not know is that you can run "Metro" Firefox even if you don't have Windows 8. It's been possible for a while to build and run on older versions of Windows using the -metrodesktop flag. Today I landed a patch to make this work on other platforms too. To build the latest elm source code on Linux or Mac OS X, follow these instructions:

Clone the elm repo: hg clone http://hg.mozilla.org/projects/elm/

(If you have already cloned mozilla-central or some other repo that shares with it, there's a faster way to do this.) Create a .mozconfig file with ac_add_options --enable-metro Build Firefox as you normally would. From your objdir, run dist/bin/firefox -metrodesktop (Linux)

or dist/Nightly.app/Contents/MacOS/firefox -metrodesktop (Mac) You can visit about:config and enable metro.debug.treatmouseastouch (then restart the browser) to simulate touch interaction with the mouse. Right-click to simulate the Windows 8 edge-swipe gesture, which displays the toolbars.

This is still experimental and mostly untested. Elm might accidentally break on non-Windows platforms from time to time (because of course we are doing all our main development and testing on Windows). While it's not a perfect replacement for running in the real Windows 8 environment, I hope this is a useful option for adventurous Firefox contributors who want to experiment with the Metro code but don't have convenient access to Windows 8.