affection/src/Affection/Draw.hs

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{-# LANGUAGE RecordWildCards #-}
-- | Module for drawing primitives
module Affection.Draw
( drawRect
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-- , clear
, handleDrawRequest
, present
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, clearArea
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) where
import Affection.Types
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import Foreign.Ptr (Ptr, plusPtr)
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import Foreign.C.Types
import Control.Monad.State (get, put)
import qualified SDL
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import qualified BABL as B
import qualified GEGL as G
-- | Draw a rectangle on target buffer
drawRect
:: G.GeglBuffer -- ^ Target buffer
-> G.GeglNode -- ^ Target node
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-> G.Color -- ^ Color to draw in
-> DrawType -- ^ Draw type
-> GeglRectangle -- ^ Dimensions of Rectangle
-> Affection us ()
drawRect buf node color (Fill) rect@G.GeglRectangle{..} = do
liftIO $ G.pixelPoke buf rect (B.PixelFormat B.RGBA B.CFdouble) G.GeglAccessReadWrite G.GeglAbyssNone $
(\(x, y) ->
let col = unsafeColorize color
in
G.Pixel x y col
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)
ad@AffectionData{..} <- get
put $ ad
{ drawStack = (DrawRequest node rect) : drawStack
}
drawRect buf node color (Line size) rect@G.GeglRectangle{..} = do
drawRect buf node color Fill (G.GeglRectangle rectangleX rectangleY rectangleWidth size)
drawRect buf node color Fill (G.GeglRectangle rectangleX rectangleY size rectangleHeight)
drawRect buf node color Fill (G.GeglRectangle (rectangleX + rectangleWidth - size) rectangleY size rectangleHeight)
drawRect buf node color Fill (G.GeglRectangle rectangleX (rectangleY + rectangleHeight - size) rectangleWidth size)
-- | force a blit of a specified area
present
:: G.GeglNode -- ^ Node to blit
-> G.GeglRectangle -- ^ Area to blit
-> Affection us ()
present node rect = do
ad@AffectionData{..} <- get
put $ ad
{ drawStack = (DrawRequest node rect) : drawStack
}
-- | function for handling 'DrawRequest's and updating the output
handleDrawRequest
:: Ptr a -- ^ Pixel buffer to blit to
-> B.BablFormatPtr -- ^ format to blit in
-> Int -- ^ Stride
-> Int -- ^ Components per Pixel
-> DrawRequest -- ^ 'DrawRequest' to handle
-> Affection us ()
handleDrawRequest pixels format stride cpp DrawRequest{..} = do
ad <- get
liftIO $ SDL.lockSurface $ drawSurface ad
liftIO $ G.gegl_node_blit
requestNode
1
requestArea
format
(pixels `plusPtr`
(rectangleX requestArea * cpp + rectangleY requestArea * stride))
stride
[G.GeglBlitDefault]
liftIO $ SDL.unlockSurface $ drawSurface ad
liftIO $ SDL.updateWindowSurface $ drawWindow ad
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-- | compute color for a single pixel
colorize
:: (G.ComponentValue, G.ComponentValue, G.ComponentValue, G.ComponentValue) -- ^ Pixel information in buffer
-> G.Color -- ^ Color to draw over
-> (G.ComponentValue, G.ComponentValue, G.ComponentValue, G.ComponentValue) -- ^ Resulting colour
colorize (rr, rg, rb, ra) col =
let (G.CVdouble (CDouble br)) = rr
(G.CVdouble (CDouble bg)) = rg
(G.CVdouble (CDouble bb)) = rb
(G.CVdouble (CDouble ba)) = ra
(cr, cg, cb) = case col of
G.RGBA r g b _ -> (r, g, b)
G.RGB r g b -> (r, g, b)
ca = case col of
G.RGBA _ _ _ a -> a
G.RGB _ _ _ -> 1
alpha = ca
dst_a = ba
da = alpha + dst_a * (1 - alpha)
a_term = dst_a * (1 - alpha)
red = cr * alpha + br * a_term
gre = cg * alpha + bg * a_term
blu = cb * alpha + bb * a_term
in
( G.CVdouble $ CDouble $ red / da
, G.CVdouble $ CDouble $ gre / da
, G.CVdouble $ CDouble $ blu / da
, G.CVdouble $ CDouble $ ca
)
unsafeColorize col =
let
(r, g, b) = case col of
G.RGBA cr cg cb _ -> (cr, cg, cb)
G.RGB cr cg cb -> (cr, cg, cb)
a = case col of
G.RGBA _ _ _ ca -> ca
G.RGB _ _ _ -> 1
in
( G.CVdouble $ CDouble $ r
, G.CVdouble $ CDouble $ g
, G.CVdouble $ CDouble $ b
, G.CVdouble $ CDouble $ a
)
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-- -- | Clear all data from a buffer
-- clear
-- :: G.GeglBuffer -- ^ Target buffer
-- -> IO ()
-- clear buf = clearArea buf =<< G.gegl_rectangle_infinite_plane
-- | Clear a specified area of a buffer from all data
clearArea
:: G.GeglBuffer -- ^ Target buffer
-> G.GeglRectangle -- ^ Area to clear
-> IO ()
clearArea = G.gegl_buffer_clear