beijaflor-io / haskell-libui

Haskell bindings to the libui C library.

haskell-libui

GPLv3

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Haskell bindings to the libui C library.

The library is currently only an FFI wrapper.

Useful top-level modules are:

• Graphics.LibUI
• Graphics.LibUI.OSX

They export general and OSX specific functionality in raw C and "wrapped" Haskell APIs. Currently implemented for OSX only are wrappers for Webkit and a partial wrapper to Mapviews, both of which have examples. This should go back to upstream libui once it's solid.

Important

This package needs some splitting and cleaning-up, as well as some more work, but the bits exposed by Graphics.LibUI.FFI (Graphics.LibUI.FFI.Wrapped, Graphics.LibUI.FFI.Raw & OSX variants) should be ok to use.

They aren't used in anything serious right now. You'd be courageous to do it.

Usage

import Graphics.LibUI
main = do
    uiInit
    wn <- uiNewWindow "Haskell on GUIs" 220 100 True
    btn <- uiNewButton "Click me"
    wn `setChild` btn
    wn `setMargined` True
    uiShow wn
    uiMain

You can run this example with:

git clone https://github.com/beijaflor-io/haskell-libui
cd haskell-libui
make READMEExample
./READMEExample

Examples

There're several examples on the examples directory. The Simple... examples only use the Graphics.LibUI.FFI part of the library and are what you want to look at first.

The ReactiveBanana... examples are playgrounds for showing how you could wrap the callback based API with FRP without much work.

markd - A simple GUI for Pandoc using a webview

apps/markd is an example application (currently only working on OSX), which previews how a file is rendered by pandoc.

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Roadmap

• Raw FFI available in Graphics.LibUI.FFI.Raw
  • All functions from the FFI mirror their libui names prefixed with c_
  • Document the FFI
• Haskell callback based API in Graphics.LibUI.FFI.Wrapped
  • Data-wrappers for uiControl type
  • Callback based API
• Higher-level API on examples and Graphics.LibUI.Types and Graphics.LibUI.MonadUI
  • Building concrete representations of UI controls based on declarative code
  • Currently in the examples Wrap the callback based code under an FRP layer
  • Library consistency
    • Containers return their concrete representation and their children's return value
    • MonadUI shouldn't wrap IO actions, but abstract commands:
      • data UI = UI [UIControl]
      • class MonadUI m b where runUI :: UI -> m b
      • instance MonadUI IO CUIControl where runUI = toCUIControlIO

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The aim of Graphics.LibUI.Types and friends is to end-up with code that looks like:

runUILoop do
    menu "File" [ "Open"
                , "Save"
                , UIMenuItemQuit
                ]
    void $ window "libui Control Gallery" 640 300 True $
        void $ tabs $ do
            tab "Basic Controls" $ do
                hbox $
                    button "Button"
                    checkbox "Checkbox"
                label "This is a label. Right now, labels can only span one line."
                void $ group "Entries" $
                    form [ formItem "Entry" (entry "")
                         , formItem "Entry" (entry "")
                         , formItem "Search Entry" (searchEntry "")
                         ]
            tab "Basic Controls" $ hbox $ do
                void $ group "Numbers" (return ())
                void $ group "Lists" (return ())
            tab "Data Choosers" mempty

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Tested on OSX, Fedora and Ubuntu 14.04. A Vagrantfile is available.

License

This code is published under the GPLv3 license