```{-# 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
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
--
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