GlyphVisAttr.hs


{- |
Copyright  : Will Thompson, Iñaki García Etxebarria and Jonas Platte
License    : LGPL-2.1
Maintainer : Iñaki García Etxebarria (garetxe@gmail.com)

The PangoGlyphVisAttr is used to communicate information between
the shaping phase and the rendering phase.  More attributes may be
added in the future.
-}

module GI.Pango.Structs.GlyphVisAttr
    ( 

-- * Exported types
    GlyphVisAttr(..)                        ,
    newZeroGlyphVisAttr                     ,
    noGlyphVisAttr                          ,


 -- * Properties
-- ** IsClusterStart
    glyphVisAttrReadIsClusterStart          ,




    ) where

import Prelude ()
import Data.GI.Base.ShortPrelude

import qualified Data.Text as T
import qualified Data.ByteString.Char8 as B
import qualified Data.Map as Map

import GI.Pango.Types
import GI.Pango.Callbacks

newtype GlyphVisAttr = GlyphVisAttr (ForeignPtr GlyphVisAttr)
-- | Construct a `GlyphVisAttr` struct initialized to zero.
newZeroGlyphVisAttr :: MonadIO m => m GlyphVisAttr
newZeroGlyphVisAttr = liftIO $ callocBytes 4 >>= wrapPtr GlyphVisAttr

noGlyphVisAttr :: Maybe GlyphVisAttr
noGlyphVisAttr = Nothing

glyphVisAttrReadIsClusterStart :: GlyphVisAttr -> IO Word32
glyphVisAttrReadIsClusterStart s = withManagedPtr s $ \ptr -> do
    val <- peek (ptr `plusPtr` 0) :: IO Word32
    return val

type family ResolveGlyphVisAttrMethod (t :: Symbol) (o :: *) :: * where
    ResolveGlyphVisAttrMethod l o = MethodResolutionFailed l o

instance (info ~ ResolveGlyphVisAttrMethod t GlyphVisAttr, MethodInfo info GlyphVisAttr p) => IsLabelProxy t (GlyphVisAttr -> p) where
    fromLabelProxy _ = overloadedMethod (MethodProxy :: MethodProxy info)

#if MIN_VERSION_base(4,9,0)
instance (info ~ ResolveGlyphVisAttrMethod t GlyphVisAttr, MethodInfo info GlyphVisAttr p) => IsLabel t (GlyphVisAttr -> p) where
    fromLabel _ = overloadedMethod (MethodProxy :: MethodProxy info)
#endif