#Awesomium with Haskell#
This is a simple usage example of Awesomium bindings for haskell.
Awesomium is an windowless port of Chromium/WebKit. You can use it to leverage the power of web browsers into your application.
Specifically my motivation for writing this wrapper was for the use in gamedev. The advantages of using this approach, as opposed to writing dedicated GUI, are numerous; you can use the powers of HTML/CSS/JS and all the tools and frameworks (like jQuery/jQueryUI, &c.) that ware and constantly are created by webdevelopers around the globe, and more importantly, you can push the GUI creation to the graphic/designer as it is more likely for him to be familiar with the web tools and languages. You can even employ your users, letting them play with the UI as they please, and later merge the more popular modes into the game. As for the disadvantages I guess it would be the performance. Obviously the dedicated GUI will be faster.
For the commercial example, AFAIK people at Wolfire are using it in their game Overgrowth.
Also, before you jump your guns, a friendly warning. Awesomium is free for non-commercial projects, but for commercial usage (if your company revenue last year was over $100K) you will need to pay $3K for a license. For the details consult their webpage.
##Instalation##
Firstly, you will need to download shared library from the http://awesomium.com and install it on your system. You should find the installation process described in the README file.
Specifically, for Ubuntu:
To install Awesomium, you'll need to add the shared library to your system's library search path. On Ubuntu, you can use the following commands:
cd awesomium_v1.6.5_sdk_linux32 sudo mkdir /usr/lib/awesomium-1.6.5 sudo cp -r build/bin/release/* /usr/lib/awesomium-1.6.5 sudo ldconfig /usr/lib/awesomium-1.6.5
Next, you'll need to download and install bindings from hackage;
If, in the previous step you have installed the shared library in
a different path than /usr/lib/awesomium-1.6.5 you will first have
to call:
cabal install awesomium-raw --extra-lib-dirs="<your-path>"
Otherwise you just have to use this commands:
cabal install awesomium
cabal install awesomium-glut
##Usage Example##
The example1, maybe not very impressive one, should have everything to get you started, so you should simply dive into the code.
Of the more interesting parts, I think, communication with JavaScript maybe worth noting.
To create API that you can call from JavaScript first you have to register a handler and specify global object and methods:
setCallbackJS wv (handle)
createObject wv "Application"
setObjectCallback wv "Application" "quit"
setObjectCallback wv "Application" "etc"Then you can easily handle callbacks from js with the function of the form:
handle :: WebView -> String -> String -> [Value] -> IO ()And where function arguments are list of Data.Aeson.Values, so
you can easily parse it for any type that provides instance of
FromJSON which can be easily automated for example by using
DeriveGeneric (as described here).
Similarly, you can call javascript functions with (surprise, surprise)
callJavascriptFunction and providing ToJSON for any types that you
may want to pass as arguments.
And this point I'd love to direct you, for details, to the package documentation on hackage. Sadly, however, hackage fails to compile the library because it cannot localize the shared lib and subsequently fails to generate the documentation files (if anyone knows how to get around this, let me know). So your options are to generate it locally or simply dive into the code.
- I would like to note that this is only an example code, so there are some practises that I wouldn't recommend you to follow, like having global mutable state (you should better check some FRP framework). Also my web-fu is not very high, and that's why it may not look very pretty.
##Acknowledgement##
One, Tom Savage, has written similar bindings (link) and though incomplete they were certainly very useful, as any previous work usually is.
