Codec.Picture.Metadata

This module expose a common "metadata" storage for various image type. Different format can generate different metadatas, and write only a part of them.

Since version 3.2.5

Types

data Metadatas

Dependent storage used for metadatas. All metadatas of a given kind are unique within this container.

The current data structure is based on list, so bad performances can be expected.

Instances

Show Metadatas

Methods

showsPrec :: Int -> Metadatas -> ShowS

show :: Metadatas -> String

showList :: [Metadatas] -> ShowS

Monoid Metadatas

Methods

mempty :: Metadatas

mappend :: Metadatas -> Metadatas -> Metadatas

mconcat :: [Metadatas] -> Metadatas

NFData Metadatas

Methods

rnf :: Metadatas -> ()

data Keys a where

Store various additional information about an image. If something is not recognized, it can be stored in an unknown tag.

• DpiX Dot per inch on this x axis.
• DpiY Dot per inch on this y axis.
• Width Image width in pixel. Relying on the metadata for this information can avoid the full decompression of the image. Ignored for image writing.
• Height Image height in pixels. Relyiung on the metadata for this information can void the full decomrpession of the image. Ignored for image writing.
• Unknown unlikely to be decoded, but usefull for metadata writing
• Exif Exif tag and associated data.

Constructors

Gamma :: Keys Double

Format :: Keys SourceFormat

DpiX :: Keys Word

DpiY :: Keys Word

Width :: Keys Word

Height :: Keys Word

Title :: Keys String

Description :: Keys String

Author :: Keys String

Copyright :: Keys String

Software :: Keys String

Comment :: Keys String

Disclaimer :: Keys String

Source :: Keys String

Warning :: Keys String

Exif :: !ExifTag -> Keys ExifData

Unknown :: !String -> Keys Value

Instances

Eq (Keys a)

Methods

(==) :: Keys a -> Keys a -> Bool

(/=) :: Keys a -> Keys a -> Bool

Show (Elem Keys)

Methods

showsPrec :: Int -> Elem Keys -> ShowS

show :: Elem Keys -> String

showList :: [Elem Keys] -> ShowS

Show (Keys a)

Methods

showsPrec :: Int -> Keys a -> ShowS

show :: Keys a -> String

showList :: [Keys a] -> ShowS

NFData (Elem Keys)

Methods

rnf :: Elem Keys -> ()

data Value

Encode values for unknown information

Constructors

Int !Int

Double !Double

String !String

Instances

Eq Value

Methods

(==) :: Value -> Value -> Bool

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

Show Value

Methods

showsPrec :: Int -> Value -> ShowS

show :: Value -> String

showList :: [Value] -> ShowS

NFData Value

Methods

rnf :: Value -> ()

data Elem k

Element describing a metadata and it's (typed) associated value.

Constructors

(Show a, NFData a) => !(k a) :=> a

Instances

Show (Elem Keys)

Methods

showsPrec :: Int -> Elem Keys -> ShowS

show :: Elem Keys -> String

showList :: [Elem Keys] -> ShowS

NFData (Elem Keys)

Methods

rnf :: Elem Keys -> ()

data SourceFormat

Type describing the original file format of the ilfe.

Constructors

SourceJpeg

SourceGif

SourceBitmap

SourceTiff

SourcePng

SourceHDR

SourceTGA

Instances

Eq SourceFormat

Methods

(==) :: SourceFormat -> SourceFormat -> Bool

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

Show SourceFormat

Methods

showsPrec :: Int -> SourceFormat -> ShowS

show :: SourceFormat -> String

showList :: [SourceFormat] -> ShowS

NFData SourceFormat

Methods

rnf :: SourceFormat -> ()

Functions

lookup :: Keys a -> Metadatas -> Maybe a

Search a metadata with the given key.

empty :: Metadatas

Empty metadatas. Favor mempty

insert :: (Show a, NFData a) => Keys a -> a -> Metadatas -> Metadatas

Insert an element in the metadatas, if an element with the same key is present, it is overwritten.

delete :: Keys a -> Metadatas -> Metadatas

Remove an element of the given keys from the metadatas. If not present does nothing.

singleton :: (Show a, NFData a) => Keys a -> a -> Metadatas

Create metadatas with a single element.

Folding

foldl' :: (acc -> Elem Keys -> acc) -> acc -> Metadatas -> acc

Strict left fold of the metadatas

foldMap :: Monoid m => (Elem Keys -> m) -> Metadatas -> m

foldMap equivalent for metadatas.

Helper functions

mkDpiMetadata :: Word -> Metadatas

Create metadatas indicating the resolution, with DpiX == DpiY

mkSizeMetadata :: Integral n => n -> n -> Metadatas

Create metadatas holding width and height information.

basicMetadata :: Integral nSize => SourceFormat -> nSize -> nSize -> Metadatas

Create simple metadatas with Format, Width & Height

simpleMetadata :: (Integral nSize, Integral nDpi) => SourceFormat -> nSize -> nSize -> nDpi -> nDpi -> Metadatas

Create simple metadatas with Format, Width, Height, DpiX & DpiY

extractExifMetas :: Metadatas -> [(ExifTag, ExifData)]

Extract all Exif specific metadatas

Conversion functions

dotsPerMeterToDotPerInch :: Word -> Word

Conversion from dpm to dpi

dotPerInchToDotsPerMeter :: Word -> Word

Conversion from dpi to dpm

dotsPerCentiMeterToDotPerInch :: Word -> Word

Conversion dpcm -> dpi