AttrSize.hs


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

The #PangoAttrSize structure is used to represent attributes which
set font size.
-}

module GI.Pango.Structs.AttrSize
    ( 

-- * Exported types
    AttrSize(..)                            ,
    newZeroAttrSize                         ,
    noAttrSize                              ,


 -- * Properties
-- ** Absolute
    attrSizeReadAbsolute                    ,


-- ** Attr
    attrSizeReadAttr                        ,


-- ** Size
    attrSizeReadSize                        ,




    ) 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 AttrSize = AttrSize (ForeignPtr AttrSize)
-- | Construct a `AttrSize` struct initialized to zero.
newZeroAttrSize :: MonadIO m => m AttrSize
newZeroAttrSize = liftIO $ callocBytes 24 >>= wrapPtr AttrSize

noAttrSize :: Maybe AttrSize
noAttrSize = Nothing

attrSizeReadAttr :: AttrSize -> IO Attribute
attrSizeReadAttr s = withManagedPtr s $ \ptr -> do
    val <- peek (ptr `plusPtr` 0) :: IO (Ptr Attribute)
    val' <- (newPtr 16 Attribute) val
    return val'

attrSizeReadSize :: AttrSize -> IO Int32
attrSizeReadSize s = withManagedPtr s $ \ptr -> do
    val <- peek (ptr `plusPtr` 16) :: IO Int32
    return val

attrSizeReadAbsolute :: AttrSize -> IO Word32
attrSizeReadAbsolute s = withManagedPtr s $ \ptr -> do
    val <- peek (ptr `plusPtr` 20) :: IO Word32
    return val

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

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

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