52 lines
1.6 KiB
Haskell
52 lines
1.6 KiB
Haskell
{-# LANGUAGE MultiParamTypeClasses, StandaloneDeriving, ExistentialQuantification, FlexibleInstances #-}
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module Phi.Widgets.AlphaBox ( AlphaBox
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, alphaBox
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) where
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import Phi.Types
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import Phi.Widget
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import Control.Monad
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import Control.Monad.State.Strict
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import Graphics.Rendering.Cairo
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data AlphaBox w s c d = (Widget w s c d) => AlphaBox !Double !w
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data AlphaBoxCache w s c d = (Widget w s c d) => AlphaBoxCache !c
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instance (Eq s, Display d) => Widget (AlphaBox w s c d) s (AlphaBoxCache w s c d) d where
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initWidget (AlphaBox _ w) = initWidget w
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initCache (AlphaBox _ w) = AlphaBoxCache $ initCache w
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minSize (AlphaBox _ w) = minSize w
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weight (AlphaBox _ w) = weight w
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render (AlphaBox alpha w) s x y width height screen = do
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AlphaBoxCache c <- get
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(surfaces, c') <- liftIO $ flip runStateT c $ render w s x y width height screen
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put $ AlphaBoxCache c'
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let surfacesWidths = zipWith (\(updated, SurfaceSlice x surf) x' -> (updated, x, x'-x, surf)) surfaces (map (\(_, SurfaceSlice x _) -> x) (tail surfaces) ++ [width])
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forM surfacesWidths $ \(updated, x, surfWidth, surf) -> do
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surf' <- liftIO $ createImageSurface FormatARGB32 surfWidth height
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renderWith surf' $ do
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setOperator OperatorSource
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withPatternForSurface surf setSource
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paint
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setOperator OperatorDestIn
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setSourceRGBA 0 0 0 alpha
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paint
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return (updated, SurfaceSlice x surf')
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handleMessage (AlphaBox _ w) = handleMessage w
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alphaBox :: (Widget w s c d) => Double -> w -> AlphaBox w s c d
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alphaBox = AlphaBox
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