A template for building new GUI applications using GTK and Cairo.
|Latest on Hackage:||0.4|
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This template includes working callbacks to handle the File and Help menus and File Save/Open dialogs, with dummy handlers for selecting filenames and the Edit menu's Cut, Copy, and Paste. The main canvas uses Cairo for graphics rendering, and includes example code from the cairo package.
To build your own application on top of this, first grab the code. You
can either grab it from hackage with
cabal unpack cairo-appbase, or
clone the git repo:
git clone git://github.com/kfish/cairo-appbase.git
To add widgets, install glade from your distro system and run
glade data/main.ui. Save the resulting file in GtkBuilder format.
Note that you must run
cabal install to put the UI file in the correct
place for your application to pick it up. To modify the code, edit
src/cairo-appbase.hs. Hooking up functions to widgets is very simple: get
a widget by name (which you set in ui file), and hook one of its
signals (which you found in the Signals tab in glade) to an
IO () action:
cut1 <- get G.castToMenuItem "cut1" G.onActivateLeaf cut1 $ myCut
The template code includes a trivial definition of myCut:
myCut :: IO () myCut = putStrLn "Cut"
A real application will want to pass data to the callback. In C, this is
fairly tedious as you only have a single void * to pass to callbacks as
user_data, and applications typically do lots of marshalling and
unmarshalling to pass data around. In Haskell however, you can make
yourself a more complex callback handler and use a curried version of it
in each instance:
cut1 <- get G.castToMenuItem "cut1" G.onActivateLeaf cut1 $ myComplexCut project phase 7 ... myCut :: Project -> MoonPhase -> LuckyNumber -> IO () myCut project phase num = do let selection = currentSelection project when (phase == Full) howl when (num /= 7) fail doActualCut selection