Picture.hs

{-# OPTIONS_HADDOCK hide #-}
{-# OPTIONS -fno-warn-orphans #-}

-- | Data types for representing pictures.
module Graphics.Gloss.Internals.Data.Picture
	( Point
	, Vector
	, Path
	, Picture(..)

        -- * Bitmaps
        , BitmapData
        , bitmapOfForeignPtr
        , bitmapOfByteString
        , bitmapOfBMP
        , loadBMP)
where
import Graphics.Gloss.Internals.Data.Color
import Graphics.Gloss.Internals.Rendering.Bitmap
import Codec.BMP
import Foreign.ForeignPtr
import Foreign.Marshal.Alloc
import Foreign.Marshal.Utils
import Foreign.Ptr
import Data.Word
import Data.Monoid
import Data.ByteString
import Data.Data
import System.IO.Unsafe
import qualified Data.ByteString.Unsafe as BSU
import Prelude hiding (map)


-- | A point on the x-y plane.
type Point      = (Float, Float)                        


-- | Pretend a point is a number.
--      Vectors aren't real numbers according to Haskell, because they don't
--      support the multiply and divide field operators. We can pretend they
--      are though, and use the (+) and (-) operators as component-wise
--      addition and subtraction.
--
instance Num Point where
        (+) (x1, y1) (x2, y2)   = (x1 + x2, y1 + y2)
        (-) (x1, y1) (x2, y2)   = (x1 - x2, y1 - y2)
        (*) (x1, y1) (x2, y2)   = (x1 * x2, y1 * y2)
        signum (x, y)           = (signum x, signum y)
        abs    (x, y)           = (abs x, abs y)
        negate (x, y)           = (negate x, negate y)  
        fromInteger x           = (fromInteger x, fromInteger x)


-- | A vector can be treated as a point, and vis-versa.
type Vector     = Point


-- | A path through the x-y plane.
type Path	= [Point]				


-- | A 2D picture
data Picture
	-- Primitives -------------------------------------

	-- | A blank picture, with nothing in it.
	= Blank

	-- | A convex polygon filled with a solid color.
	| Polygon 	Path
	
	-- | A line along an arbitrary path.
	| Line		Path

	-- | A circle with the given radius.
	| Circle	Float

	-- | A circle with the given thickness and radius.
	--   If the thickness is 0 then this is equivalent to `Circle`.
	| ThickCircle	Float Float

	-- | A circular arc drawn counter-clockwise between two angles 
        --  (in degrees) at the given radius.
        | Arc           Float Float Float

	-- | A circular arc drawn counter-clockwise between two angles 
        --  (in degrees), with the given radius  and thickness.
	--   If the thickness is 0 then this is equivalent to `Arc`.
        | ThickArc	Float Float Float Float

	-- | Some text to draw with a vector font.
	| Text		String

	-- | A bitmap image with a width, height and some 32-bit RGBA
        --   bitmap data.
	-- 
	--  The boolean flag controls whether Gloss should cache the data
        --  between frames for speed. If you are programatically generating
        --  the image for each frame then use `False`. If you have loaded it
        --  from a file then use `True`.
	| Bitmap	Int	Int 	BitmapData Bool

	-- Color ------------------------------------------
	-- | A picture drawn with this color.
	| Color		Color  		Picture

	-- Transforms -------------------------------------
	-- | A picture translated by the given x and y coordinates.
	| Translate	Float Float	Picture

	-- | A picture rotated clockwise by the given angle (in degrees).
	| Rotate	Float		Picture

	-- | A picture scaled by the given x and y factors.
	| Scale		Float	Float	Picture

	-- More Pictures ----------------------------------
	-- | A picture consisting of several others.
	| Pictures	[Picture]
	deriving (Show, Eq, Data, Typeable)


-- Instances ------------------------------------------------------------------
instance Monoid Picture where
	mempty		= Blank
	mappend a b	= Pictures [a, b]
	mconcat		= Pictures


-- Bitmaps --------------------------------------------------------------------
-- | O(1). Use a `ForeignPtr` of RGBA data as a bitmap with the given
--   width and height.

--   The boolean flag controls whether Gloss should cache the data
--   between frames for speed. If you are programatically generating
--   the image for each frame then use `False`. If you have loaded it
--   from a file then use `True`.
bitmapOfForeignPtr :: Int -> Int -> ForeignPtr Word8 -> Bool -> Picture
bitmapOfForeignPtr width height fptr cacheMe
 = let  len     = width * height * 4
        bdata   = BitmapData len fptr
   in   Bitmap width height bdata cacheMe 


-- | O(size). Copy a `ByteString` of RGBA data into a bitmap with the given
--   width and height.
--
--   The boolean flag controls whether Gloss should cache the data
--   between frames for speed. If you are programatically generating
--   the image for each frame then use `False`. If you have loaded it
--   from a file then use `True`.
{-# NOINLINE bitmapOfByteString #-}
bitmapOfByteString :: Int -> Int -> ByteString -> Bool -> Picture
bitmapOfByteString width height bs cacheMe
 = unsafePerformIO
 $ do   let len = width * height * 4
        ptr     <- mallocBytes len
        fptr    <- newForeignPtr finalizerFree ptr

        BSU.unsafeUseAsCString bs
         $ \cstr -> copyBytes ptr (castPtr cstr) len

        let bdata = BitmapData len fptr
        return $ Bitmap width height bdata cacheMe


-- | O(size). Copy a `BMP` file into a bitmap.
{-# NOINLINE bitmapOfBMP #-}
bitmapOfBMP :: BMP -> Picture
bitmapOfBMP bmp
 = unsafePerformIO
 $ do   let (width, height)     = bmpDimensions bmp
        let bs                  = unpackBMPToRGBA32 bmp 
        let len                 = width * height * 4

        ptr     <- mallocBytes len
        fptr    <- newForeignPtr finalizerFree ptr

        BSU.unsafeUseAsCString bs
         $ \cstr -> copyBytes ptr (castPtr cstr) len

        let bdata = BitmapData len fptr
        reverseRGBA bdata

        return $ Bitmap width height bdata True


-- | Load an uncompressed 24 or 32bit RGBA BMP file as a bitmap.
loadBMP :: FilePath -> IO Picture
loadBMP filePath
 = do   ebmp    <- readBMP filePath
        case ebmp of
         Left err       -> error $ show err
         Right bmp      -> return $ bitmapOfBMP bmp