Safe Haskell	None
Language	Haskell2010

Codec.Picture.Gif

Contents

Reading
Writing

Description

Module implementing GIF decoding.

Synopsis

decodeGif :: ByteString -> Either String DynamicImage
decodeGifWithMetadata :: ByteString -> Either String (DynamicImage, Metadatas)
decodeGifWithPaletteAndMetadata :: ByteString -> Either String (PalettedImage, Metadatas)
decodeGifImages :: ByteString -> Either String [DynamicImage]
getDelaysGifImages :: ByteString -> Either String [GifDelay]
type GifDelay = Int
data GifDisposalMethod
data GifEncode = GifEncode {
- geWidth :: Int
- geHeight :: Int
- gePalette :: Maybe Palette
- geBackground :: Maybe Int
- geLooping :: GifLooping
- geFrames :: [GifFrame]
}
data GifFrame = GifFrame {
- gfXOffset :: Int
- gfYOffset :: Int
- gfPalette :: Maybe Palette
- gfTransparent :: Maybe Int
- gfDelay :: GifDelay
- gfDisposal :: GifDisposalMethod
- gfPixels :: Image Pixel8
}
data GifLooping
- = LoopingNever
- | LoopingForever
- | LoopingRepeat Word16
encodeGifImage :: Image Pixel8 -> ByteString
encodeGifImageWithPalette :: Image Pixel8 -> Palette -> Either String ByteString
encodeGifImages :: GifLooping -> [(Palette, GifDelay, Image Pixel8)] -> Either String ByteString
encodeComplexGifImage :: GifEncode -> Either String ByteString
writeGifImage :: FilePath -> Image Pixel8 -> IO ()
writeGifImageWithPalette :: FilePath -> Image Pixel8 -> Palette -> Either String (IO ())
writeGifImages :: FilePath -> GifLooping -> [(Palette, GifDelay, Image Pixel8)] -> Either String (IO ())
writeComplexGifImage :: FilePath -> GifEncode -> Either String (IO ())
greyPalette :: Palette

Reading

decodeGif :: ByteString -> Either String DynamicImage #

Transform a raw gif image to an image, without modifying the pixels. This function can output the following images:

ImageRGB8
ImageRGBA8

decodeGifWithMetadata :: ByteString -> Either String (DynamicImage, Metadatas) #

Transform a raw gif image to an image, without modifying the pixels. This function can output the following images:

ImageRGB8
ImageRGBA8

Metadatas include Width & Height information.

decodeGifWithPaletteAndMetadata :: ByteString -> Either String (PalettedImage, Metadatas) #

Return the gif image with metadata and palette. The palette is only returned for the first image of an animation and has no transparency.

decodeGifImages :: ByteString -> Either String [DynamicImage] #

Transform a raw gif to a list of images, representing all the images of an animation.

getDelaysGifImages :: ByteString -> Either String [GifDelay] #

Extract a list of frame delays from a raw gif.

Writing

type GifDelay = Int #

Delay to wait before showing the next Gif image. The delay is expressed in 100th of seconds.

data GifDisposalMethod #

Constructors

DisposalAny
DisposalDoNot
DisposalRestoreBackground
DisposalRestorePrevious
DisposalUnknown Word8

data GifEncode #

GIF image definition for encoding

Constructors

GifEncode
Fields geWidth :: Int Screen width geHeight :: Int Screen height gePalette :: Maybe Palette Global palette, optional geBackground :: Maybe Int Background color index, optional. If given, a global palette is also required geLooping :: GifLooping Looping behaviour geFrames :: [GifFrame] Image frames

data GifFrame #

An individual image frame in a GIF image

Constructors

GifFrame

Fields

gfXOffset :: Int
Image X offset in GIF canvas
gfYOffset :: Int
Image Y offset in GIF canvas
gfPalette :: Maybe Palette
Image local palette, optional if a global palette is given
gfTransparent :: Maybe Int
Transparent color index, optional
gfDelay :: GifDelay
Frame transition delay, in 1/100ths of a second
gfDisposal :: GifDisposalMethod
Frame disposal method
gfPixels :: Image Pixel8
Image pixels

data GifLooping #

Help to control the behaviour of GIF animation looping.

Constructors

LoopingNever	The animation will stop once the end is reached
LoopingForever	The animation will restart once the end is reached
LoopingRepeat Word16	The animation will repeat n times before stoping

encodeGifImage :: Image Pixel8 -> ByteString #

Encode a greyscale image to a bytestring.

encodeGifImageWithPalette :: Image Pixel8 -> Palette -> Either String ByteString #

Encode an image with a given palette. Can return errors if the palette is ill-formed.

A palette must have between 1 and 256 colors

encodeGifImages :: GifLooping -> [(Palette, GifDelay, Image Pixel8)] -> Either String ByteString #

Encode a gif animation to a bytestring.

Every image must have the same size
Every palette must have between one and 256 colors.

encodeComplexGifImage :: GifEncode -> Either String ByteString #

Encode a complex gif to a bytestring.

There must be at least one image.
The screen and every frame dimensions must be between 1 and 65535.
Every frame image must fit within the screen bounds.
Every palette must have between one and 256 colors.
There must be a global palette or every image must have a local palette.
The background color index must be present in the global palette.
Every frame's transparent color index, if set, must be present in the palette used by that frame.
Every color index used in an image must be present in the palette used by that frame.

writeGifImage :: FilePath -> Image Pixel8 -> IO () #

Write a greyscale in a gif file on the disk.

writeGifImageWithPalette :: FilePath -> Image Pixel8 -> Palette -> Either String (IO ()) #

Write a gif image with a palette to a file.

A palette must have between 1 and 256 colors

writeGifImages :: FilePath -> GifLooping -> [(Palette, GifDelay, Image Pixel8)] -> Either String (IO ()) #

Write a list of images as a gif animation in a file.

Every image must have the same size
Every palette must have between one and 256 colors.

writeComplexGifImage :: FilePath -> GifEncode -> Either String (IO ()) #

greyPalette :: Palette #

Default palette to produce greyscale images.