Codec.Picture.Types

Module providing the basic types for image manipulation in the library. Defining the types used to store all those _Juicy Pixels_

Types

Image types

data Image a

Image or pixel buffer, the coordinates are assumed to start from the upper-left corner of the image, with the horizontal position first, then the vertical one.

Constructors

Image

Fields

imageWidth :: !Int

Width of the image in pixels

imageHeight :: !Int

Height of the image in pixels.

imageData :: UArray Int Word8

The real image, to extract pixels at some position you should use the helpers functions.

data MutableImage s a

Image or pixel buffer, the coordinates are assumed to start from the upper-left corner of the image, with the horizontal position first, then the vertical one. The image can be transformed in place.

Constructors

MutableImage

Fields

mutableImageWidth :: !Int

Width of the image in pixels

mutableImageHeight :: !Int

Height of the image in pixels.

mutableImageData :: STUArray s Int Word8

The real image, to extract pixels at some position you should use the helpers functions.

data DynamicImage

Type allowing the loading of an image with different pixel structures

Constructors

ImageY8 (Image Pixel8)

A greyscale image.

ImageYA8 (Image PixelYA8)

An image in greyscale with an alpha channel.

ImageRGB8 (Image PixelRGB8)

An image in true color.

ImageRGBA8 (Image PixelRGBA8)

An image in true color and an alpha channel.

ImageYCbCr8 (Image PixelYCbCr8)

An image in the colorspace used by Jpeg images.

data PixelType

Describe pixel kind at runtime

Constructors

PixelMonochromatic

For 2 bits pixels

PixelGreyscale

PixelGreyscaleAlpha

PixelRedGreenBlue8

PixelRedGreenBlueAlpha8

PixelYChromaRChromaB8

Instances

Eq PixelType

Pixel types

type Pixel8 = Word8

Simple alias for greyscale value in 8 bits.

data PixelYA8

Pixel type storing Luminance (Y) and alpha information on 8 bits. Value are stored in the following order :

• Luminance
• Alpha

Constructors

PixelYA8 !Word8 !Word8

Instances

Serialize PixelYA8

Pixel PixelYA8

ColorConvertible PixelYA8 PixelRGBA8

ColorConvertible PixelYA8 PixelRGB8

ColorConvertible Pixel8 PixelYA8

data PixelRGB8

Pixel type storing classic pixel on 8 bits Value are stored in the following order :

• Red
• Green
• Blue

Constructors

PixelRGB8 !Word8 !Word8 !Word8

Instances

Serialize PixelRGB8

Pixel PixelRGB8

PngSavable PixelRGB8

BmpEncodable PixelRGB8

ColorSpaceConvertible PixelYCbCr8 PixelRGB8

ColorConvertible PixelRGB8 PixelRGBA8

ColorConvertible PixelYA8 PixelRGB8

ColorConvertible Pixel8 PixelRGB8

data PixelRGBA8

Pixel type storing a classic pixel, with an alpha component. Values are stored in the following order

• Red
• Green
• Blue
• Alpha

Constructors

PixelRGBA8 !Word8 !Word8 !Word8 !Word8

Instances

Serialize PixelRGBA8

Pixel PixelRGBA8

PngSavable PixelRGBA8

BmpEncodable PixelRGBA8

ColorConvertible PixelRGB8 PixelRGBA8

ColorConvertible PixelYA8 PixelRGBA8

ColorConvertible Pixel8 PixelRGBA8

data PixelYCbCr8

Pixel storing data in the YCbCr colorspace, value are stored in teh following order :

• Y (luminance)
• Cr
• Cb

Constructors

PixelYCbCr8 !Word8 !Word8 !Word8

Instances

Serialize PixelYCbCr8

Pixel PixelYCbCr8

ColorSpaceConvertible PixelYCbCr8 PixelRGB8

Type classes

class (Pixel a, Pixel b) => ColorConvertible a b where

Implement upcasting for pixel types Minimal declaration declaration promotePixel It is strongly recommanded to overload promoteImage to keep performance acceptable

Methods

promotePixel :: a -> b

Convert a pixel type to another pixel type. This operation should never loss any data.

promoteImage :: Image a -> Image b

Change the underlying pixel type of an image by performing a full copy of it.

Instances

Pixel a => ColorConvertible a a

Free promotion for identic pixel types

ColorConvertible PixelRGB8 PixelRGBA8

ColorConvertible PixelYA8 PixelRGBA8

ColorConvertible PixelYA8 PixelRGB8

ColorConvertible Pixel8 PixelRGBA8

ColorConvertible Pixel8 PixelRGB8

ColorConvertible Pixel8 PixelYA8

class Serialize a => Pixel a where

Typeclass used to query a type about it's properties regarding casting to other pixel types

Methods

canPromoteTo :: a -> PixelType -> Bool

Tell if a pixel can be converted to another pixel, the first value should not be used, and undefined can be used as a valid value.

componentCount :: a -> Int

Return the number of component of the pixel

pixelBaseIndex :: Image a -> Int -> Int -> Int

Calculate the index for the begining of the pixel

mutablePixelBaseIndex :: MutableImage s a -> Int -> Int -> Int

Calculate theindex for the begining of the pixel at position x y

promotionType :: a -> PixelType

Return the constructor associated to the type, again the value in the first parameter is not used, so you can use undefined

pixelAt :: Image a -> Int -> Int -> a

Extract a pixel at a given position, (x, y), the origin is assumed to be at the corner top left, positive y to the bottom of the image

readPixel :: MutableImage s a -> Int -> Int -> ST s a

Same as pixelAt but for mutable images.

writePixel :: MutableImage s a -> Int -> Int -> a -> ST s ()

Write a pixel in a mutable image at position x y

Instances

Pixel PixelRGBA8

Pixel PixelYCbCr8

Pixel PixelRGB8

Pixel PixelYA8

Pixel Pixel8

class (Pixel a, Pixel b) => ColorSpaceConvertible a b where

This class abstract colorspace conversion. This conversion can be lossy, which ColorConvertible cannot

Methods

convertPixel :: a -> b

convertImage :: Image a -> Image b

Instances

ColorSpaceConvertible PixelYCbCr8 PixelRGB8

Helper functions

canConvertTo :: (Pixel a, Pixel b) => a -> b -> Bool

Tell if you can convert between two pixel types, both arguments are unused.