Hakyll.Images.CompressJpg

This module defines a Hakyll compiler, compressJpgCompiler, which can be used to re-encode Jpeg images at a lower quality during website compilation. Original images are left unchanged, but compressed images can be up to 10x smaller.

The compressJpgCompiler is expected to be used like this:

    import Hakyll
    import Hakyll.Images        ( loadImage
                                , compressJpgCompiler
                                )

    hakyll $ do

        -- Compress all source Jpegs to a Jpeg quality of 50
        match "images/**.jpg" $ do
            route idRoute
            compile $ loadImage
                >>= compressJpgCompiler 50

        (... omitted ...)

Documentation

data JpgQuality

Jpeg encoding quality, from 0 (lower quality) to 100 (best quality). @since 1.2.0

Instances

Enum JpgQuality

Defined in Hakyll.Images.CompressJpg

Methods

succ :: JpgQuality -> JpgQuality

pred :: JpgQuality -> JpgQuality

toEnum :: Int -> JpgQuality

fromEnum :: JpgQuality -> Int

enumFrom :: JpgQuality -> [JpgQuality]

enumFromThen :: JpgQuality -> JpgQuality -> [JpgQuality]

enumFromTo :: JpgQuality -> JpgQuality -> [JpgQuality]

enumFromThenTo :: JpgQuality -> JpgQuality -> JpgQuality -> [JpgQuality]

Num JpgQuality

Defined in Hakyll.Images.CompressJpg

Methods

(+) :: JpgQuality -> JpgQuality -> JpgQuality

(-) :: JpgQuality -> JpgQuality -> JpgQuality

(*) :: JpgQuality -> JpgQuality -> JpgQuality

negate :: JpgQuality -> JpgQuality

abs :: JpgQuality -> JpgQuality

signum :: JpgQuality -> JpgQuality

fromInteger :: Integer -> JpgQuality

Integral JpgQuality

Defined in Hakyll.Images.CompressJpg

Methods

quot :: JpgQuality -> JpgQuality -> JpgQuality

rem :: JpgQuality -> JpgQuality -> JpgQuality

div :: JpgQuality -> JpgQuality -> JpgQuality

mod :: JpgQuality -> JpgQuality -> JpgQuality

quotRem :: JpgQuality -> JpgQuality -> (JpgQuality, JpgQuality)

divMod :: JpgQuality -> JpgQuality -> (JpgQuality, JpgQuality)

toInteger :: JpgQuality -> Integer

Real JpgQuality

Defined in Hakyll.Images.CompressJpg

Methods

toRational :: JpgQuality -> Rational

Eq JpgQuality

Defined in Hakyll.Images.CompressJpg

Methods

(==) :: JpgQuality -> JpgQuality -> Bool

(/=) :: JpgQuality -> JpgQuality -> Bool

Ord JpgQuality

Defined in Hakyll.Images.CompressJpg

Methods

compare :: JpgQuality -> JpgQuality -> Ordering

(<) :: JpgQuality -> JpgQuality -> Bool

(<=) :: JpgQuality -> JpgQuality -> Bool

(>) :: JpgQuality -> JpgQuality -> Bool

(>=) :: JpgQuality -> JpgQuality -> Bool

max :: JpgQuality -> JpgQuality -> JpgQuality

min :: JpgQuality -> JpgQuality -> JpgQuality

compressJpgCompiler :: Integral a => a -> Item Image -> Compiler (Item Image)

Compiler that compresses a JPG image to a certain quality setting. The quality should be between 0 (lowest quality) and 100 (best quality). Values outside of this range will be normalized to the interval [0, 100]. An error is raised if the image cannot be decoded.

match "*.jpg" $ do
    route idRoute
    compile $ loadImage
        >>= compressJpgCompiler 50

compressJpg :: Integral a => a -> Image -> Image

Compress a JPG bytestring to a certain quality setting. The quality should be between 0 (lowest quality) and 100 (best quality). An error is raised if the image cannot be decoded.

In the rare case where the JPEG data contains transparency information, it will be dropped.