ModuleJuicyPixels-3.3.8Haskell2010

Codec.Picture.Png

Module used for loading & writing 'Portable Network Graphics' (PNG) files.

A high level API is provided. It loads and saves images for you while hiding all the details about PNG chunks.

Basic functions for PNG handling are decodePng, encodePng and encodePalettedPng. Convenience functions are provided for direct file handling and using DynamicImages.

The loader has been validated against the pngsuite (http:/www.libpng.orgpubpngpngsuite.html)

2 classes
6 values

PackageJuicyPixels-3.3.8
Exports8
LanguageHaskell2010
LicenceBSD-3-Clause
SourcePng.hs

High level functions

8 declarations

classclass PngSavable a where

Encode an image into a png if possible.

Methods

encodePng :: Image a -> ByteString
Transform an image into a png encoded bytestring, ready to be written as a file.
encodePngWithMetadata :: Metadatas -> Image a -> ByteString
Encode a png using some metadatas. The following metadata keys will be stored in a tEXt field :
- Title
- Description
- Author
- Copyright
- Software
- Comment
- Disclaimer
- Source
- Warning
- Unknown using the key present in the constructor.
the followings metadata will be stored in the gAMA chunk.
- Gamma
The followings metadata will be stored in a pHYs chunk
- DpiX
- DpiY

Instances8PngSavable, …

PngSavable Pixel16Defined in JuicyPixels-3.3.8 · Codec.Picture.Png.Internal.Export
PngSavable Pixel8Defined in JuicyPixels-3.3.8 · Codec.Picture.Png.Internal.Export
PngSavable PixelRGB16Defined in JuicyPixels-3.3.8 · Codec.Picture.Png.Internal.Export
PngSavable PixelRGB8Defined in JuicyPixels-3.3.8 · Codec.Picture.Png.Internal.Export
PngSavable PixelRGBA16Defined in JuicyPixels-3.3.8 · Codec.Picture.Png.Internal.Export
PngSavable PixelRGBA8Defined in JuicyPixels-3.3.8 · Codec.Picture.Png.Internal.Export
PngSavable PixelYA16Defined in JuicyPixels-3.3.8 · Codec.Picture.Png.Internal.Export
PngSavable PixelYA8Defined in JuicyPixels-3.3.8 · Codec.Picture.Png.Internal.Export

classclass PngPaletteSaveable a where

Encode a paletted image into a png if possible.

Methods

encodePalettedPng :: Image a -> Image Pixel8 -> Either String ByteString
Encode a paletted image as a color indexed 8-bit PNG. the palette must have between 1 and 256 values in it. Accepts PixelRGB8 and PixelRGBA8 as palette pixel type
encodePalettedPngWithMetadata :: Metadatas -> Image a -> Image Pixel8 -> Either String ByteString
Equivalent to encodePalettedPng but allow writing of metadatas. See encodePngWithMetadata for the details of encoded metadatas Accepts PixelRGB8 and PixelRGBA8 as palette pixel type

Instances2PngPaletteSaveable

PngPaletteSaveable PixelRGB8Defined in JuicyPixels-3.3.8 · Codec.Picture.Png.Internal.Export
PngPaletteSaveable PixelRGBA8Defined in JuicyPixels-3.3.8 · Codec.Picture.Png.Internal.Export

valuedecodePng :: ByteString -> Either String DynamicImage

Transform a raw png image to an image, without modifying the underlying pixel type. If the image is greyscale and < 8 bits, a transformation to RGBA8 is performed. This should change in the future. The resulting image let you manage the pixel types.

This function can output the following images:

valuedecodePngWithMetadata

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

Decode a PNG file with, possibly, separated palette.

valuedecodePngWithPaletteAndMetadata

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

Same as decodePng but also extract meta datas present in the files.

valuewritePng :: PngSavable pixel => FilePath -> Image pixel -> IO ()

Helper function to directly write an image as a png on disk.

valueencodeDynamicPng :: DynamicImage -> Either String ByteString

Encode a dynamic image in PNG if possible, supported images are:

valuewriteDynamicPng :: FilePath -> DynamicImage -> IO (Either String Bool)

Write a dynamic image in a .png image file if possible. The same restriction as encodeDynamicPng apply.