-- |
-- Module      : Hakyll.Images.Resize
-- Description : Hakyll compiler to resize images
-- Copyright   : (c) Laurent P René de Cotret, 2019 - present
-- License     : BSD3
-- Maintainer  : laurent.decotret@outlook.com
-- Stability   : unstable
-- Portability : portable
--
-- This module defines two Hakyll compilers. The first one, 'resizeImageCompiler',
-- is used to resize images to specific dimensions. The aspect ratio might not be the same.
--
-- The other compiler, `scaleImageCompiler`, scales images to fit within a specified
-- box while preserving aspect ratio.
--
-- @
--     import Hakyll
--     import Hakyll.Images        ( loadImage
--                                 , resizeImageCompiler
--                                 , scaleImageCompiler
--                                 )
--
--     hakyll $ do
--
--         -- Resize all profile pictures with .png extensions to 64x48
--         match "profiles/**.png" $ do
--             route idRoute
--             compile $ loadImage >>= resizeImageCompiler 64 48
--
--         -- Scale images to fit within a 600x400 box
--         match "images/**" $ do
--             route idRoute
--             compile $ loadImage >>= scaleImageCompiler 600 400
--
--         (... omitted ...)
-- @
module Hakyll.Images.Resize
  ( Width,
    Height,
    resize,
    resizeImageCompiler,
    scale,
    scaleImageCompiler,
    ensureFit,
    ensureFitCompiler,
  )
where

import Codec.Picture (convertRGBA8)
import Codec.Picture.Extra (scaleBilinear)
import Codec.Picture.Types (DynamicImage (..), imageHeight, imageWidth)
import Data.Ratio ((%))
import Hakyll.Core.Compiler (Compiler)
import Hakyll.Core.Item (Item (..))
import Hakyll.Images.Common (Image (..), ImageContent, WithMetadata (..), encode, withImageContent)

type Width = Int

type Height = Int

-- | Resize an image to specified width and height using the bilinear transform.
-- The aspect ratio may not be respected.
--
-- In the process, an image is converted to RGBA8. Therefore, some information
-- loss may occur.
resize :: Width -> Height -> ImageContent -> ImageContent
resize :: Width -> Width -> ImageContent -> ImageContent
resize Width
w Width
h = (DynamicImage -> DynamicImage) -> ImageContent -> ImageContent
forall a b. (a -> b) -> WithMetadata a -> WithMetadata b
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap (Image PixelRGBA8 -> DynamicImage
ImageRGBA8 (Image PixelRGBA8 -> DynamicImage)
-> (DynamicImage -> Image PixelRGBA8)
-> DynamicImage
-> DynamicImage
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Width -> Width -> Image PixelRGBA8 -> Image PixelRGBA8
forall a.
(Pixel a, Bounded (PixelBaseComponent a),
 Integral (PixelBaseComponent a)) =>
Width -> Width -> Image a -> Image a
scaleBilinear Width
w Width
h (Image PixelRGBA8 -> Image PixelRGBA8)
-> (DynamicImage -> Image PixelRGBA8)
-> DynamicImage
-> Image PixelRGBA8
forall b c a. (b -> c) -> (a -> b) -> a -> c
. DynamicImage -> Image PixelRGBA8
convertRGBA8)

-- | Scale an image to a size that will fit in the specified width and height,
-- while preserving aspect ratio. Images might be scaled up as well.
--
-- In the process, an image is converted to RGBA8. Therefore, some information
-- loss may occur.
--
-- To scale images down only, take a look at 'ensureFit'.
scale :: Width -> Height -> ImageContent -> ImageContent
scale :: Width -> Width -> ImageContent -> ImageContent
scale Width
w Width
h = Width -> Width -> Bool -> ImageContent -> ImageContent
scale' Width
w Width
h Bool
True

-- | Scale an image to a size that will fit in the specified width and height,
-- while preserving aspect ratio. Images might be scaled up as well.
--
-- In the process, an image is converted to RGBA8. Therefore, some information
-- loss may occur.
scale' ::
  -- | Desired width.
  Width ->
  -- | Desired height.
  Height ->
  -- | Allow scaling up as well.
  Bool ->
  -- | Source image
  ImageContent ->
  -- | Scaled image.
  ImageContent
scale' :: Width -> Width -> Bool -> ImageContent -> ImageContent
scale' Width
w Width
h Bool
upAllowed content :: ImageContent
content@(MkWithMetadata DynamicImage
img Metadatas
_) = Width -> Width -> ImageContent -> ImageContent
resize Width
maxWidth Width
maxHeight ImageContent
content
  where
    img' :: Image PixelRGBA8
img' = DynamicImage -> Image PixelRGBA8
convertRGBA8 DynamicImage
img -- Required to extract height and width
    (Width
imgWidth, Width
imgHeight) = (Image PixelRGBA8 -> Width
forall a. Image a -> Width
imageWidth Image PixelRGBA8
img', Image PixelRGBA8 -> Width
forall a. Image a -> Width
imageHeight Image PixelRGBA8
img')
    -- Find the smallest resizing that will accomodate both the width
    -- and height.
    -- If we don't allow scaling up, minimum scaling is 1
    resizing :: Ratio Width
resizing =
      if Bool
upAllowed
        then Ratio Width -> Ratio Width -> Ratio Width
forall a. Ord a => a -> a -> a
min (Width
w Width -> Width -> Ratio Width
forall a. Integral a => a -> a -> Ratio a
% Width
imgWidth) (Width
h Width -> Width -> Ratio Width
forall a. Integral a => a -> a -> Ratio a
% Width
imgHeight)
        else [Ratio Width] -> Ratio Width
forall a. Ord a => [a] -> a
forall (t :: * -> *) a. (Foldable t, Ord a) => t a -> a
minimum [Width
w Width -> Width -> Ratio Width
forall a. Integral a => a -> a -> Ratio a
% Width
imgWidth, Width
h Width -> Width -> Ratio Width
forall a. Integral a => a -> a -> Ratio a
% Width
imgHeight, Ratio Width
1]
    maxWidth :: Width
maxWidth = Ratio Width -> Width
forall b. Integral b => Ratio Width -> b
forall a b. (RealFrac a, Integral b) => a -> b
round (Ratio Width
resizing Ratio Width -> Ratio Width -> Ratio Width
forall a. Num a => a -> a -> a
* Width -> Ratio Width
forall a b. (Integral a, Num b) => a -> b
fromIntegral Width
imgWidth)
    maxHeight :: Width
maxHeight = Ratio Width -> Width
forall b. Integral b => Ratio Width -> b
forall a b. (RealFrac a, Integral b) => a -> b
round (Ratio Width
resizing Ratio Width -> Ratio Width -> Ratio Width
forall a. Num a => a -> a -> a
* Width -> Ratio Width
forall a b. (Integral a, Num b) => a -> b
fromIntegral Width
imgHeight)

-- | Scale an image down to a size that will fit in the specified width and height,
-- while preserving aspect ratio.
--
-- In the process, an image is converted to RGBA8. Therefore, some information
-- loss may occur.
--
-- To scale images up __or__ down, take a look at 'scale'.
ensureFit :: Width -> Height -> ImageContent -> ImageContent
ensureFit :: Width -> Width -> ImageContent -> ImageContent
ensureFit Width
w Width
h = Width -> Width -> Bool -> ImageContent -> ImageContent
scale' Width
w Width
h Bool
False

-- | Compiler that resizes images to a specific dimensions. Aspect ratio
-- may not be preserved.
--
-- @
-- match "*.png" $ do
--    route idRoute
--    compile $ loadImage >>= resizeImageCompiler 48 64
-- @
--
-- Note that in the resizing process, images will be converted to RGBA8.
-- To preserve aspect ratio, take a look at 'scaleImageCompiler'.
resizeImageCompiler :: Width -> Height -> Item Image -> Compiler (Item Image)
resizeImageCompiler :: Width -> Width -> Item Image -> Compiler (Item Image)
resizeImageCompiler Width
w Width
h = Item Image -> Compiler (Item Image)
forall a. a -> Compiler a
forall (m :: * -> *) a. Monad m => a -> m a
return (Item Image -> Compiler (Item Image))
-> (Item Image -> Item Image)
-> Item Image
-> Compiler (Item Image)
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (Image -> Image) -> Item Image -> Item Image
forall a b. (a -> b) -> Item a -> Item b
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap ((ImageContent -> ImageContent)
-> (ImageFormat -> ImageContent -> Image) -> Image -> Image
withImageContent (Width -> Width -> ImageContent -> ImageContent
resize Width
w Width
h) ImageFormat -> ImageContent -> Image
encode)

-- | Compiler that rescales images to fit within dimensions. Aspect ratio
-- will be preserved. Images might be scaled up as well.
--
-- @
-- match "*.tiff" $ do
--    route idRoute
--    compile $ loadImage >>= scaleImageCompiler 48 64
-- @
--
-- Note that in the resizing process, images will be converted to RGBA8.
-- To ensure images are only scaled __down__, take a look at 'ensureFitCompiler'.
scaleImageCompiler :: Width -> Height -> Item Image -> Compiler (Item Image)
scaleImageCompiler :: Width -> Width -> Item Image -> Compiler (Item Image)
scaleImageCompiler Width
w Width
h = Item Image -> Compiler (Item Image)
forall a. a -> Compiler a
forall (m :: * -> *) a. Monad m => a -> m a
return (Item Image -> Compiler (Item Image))
-> (Item Image -> Item Image)
-> Item Image
-> Compiler (Item Image)
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (Image -> Image) -> Item Image -> Item Image
forall a b. (a -> b) -> Item a -> Item b
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap ((ImageContent -> ImageContent)
-> (ImageFormat -> ImageContent -> Image) -> Image -> Image
withImageContent (Width -> Width -> ImageContent -> ImageContent
scale Width
w Width
h) ImageFormat -> ImageContent -> Image
encode)

-- | Compiler that ensures images will fit within dimensions. Images might
-- be scaled down, but never up.  Aspect ratio will be preserved.
--
-- @
-- match "*.tiff" $ do
--    route idRoute
--    compile $ loadImage >>= ensureFitCompiler 48 64
-- @
--
-- Note that in the resizing process, images will be converted to RGBA8.
-- To allow the possibility of scaling up, take a look at 'scaleImageCompiler'.
ensureFitCompiler :: Width -> Height -> Item Image -> Compiler (Item Image)
ensureFitCompiler :: Width -> Width -> Item Image -> Compiler (Item Image)
ensureFitCompiler Width
w Width
h = Item Image -> Compiler (Item Image)
forall a. a -> Compiler a
forall (m :: * -> *) a. Monad m => a -> m a
return (Item Image -> Compiler (Item Image))
-> (Item Image -> Item Image)
-> Item Image
-> Compiler (Item Image)
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (Image -> Image) -> Item Image -> Item Image
forall a b. (a -> b) -> Item a -> Item b
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap ((ImageContent -> ImageContent)
-> (ImageFormat -> ImageContent -> Image) -> Image -> Image
withImageContent (Width -> Width -> ImageContent -> ImageContent
ensureFit Width
w Width
h) ImageFormat -> ImageContent -> Image
encode)