Safe Haskell | None |
---|---|
Language | Haskell2010 |
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
- data Metadatas
- data Keys a where
- 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
- data Value
- data Elem k = forall a . (Show a, NFData a) => !(k a) :=> a
- data SourceFormat
- lookup :: Keys a -> Metadatas -> Maybe a
- empty :: Metadatas
- insert :: (Show a, NFData a) => Keys a -> a -> Metadatas -> Metadatas
- delete :: Keys a -> Metadatas -> Metadatas
- singleton :: (Show a, NFData a) => Keys a -> a -> Metadatas
- foldl' :: (acc -> Elem Keys -> acc) -> acc -> Metadatas -> acc
- foldMap :: Monoid m => (Elem Keys -> m) -> Metadatas -> m
- mkDpiMetadata :: Word -> Metadatas
- mkSizeMetadata :: Integral n => n -> n -> Metadatas
- basicMetadata :: Integral nSize => SourceFormat -> nSize -> nSize -> Metadatas
- simpleMetadata :: (Integral nSize, Integral nDpi) => SourceFormat -> nSize -> nSize -> nDpi -> nDpi -> Metadatas
- dotsPerMeterToDotPerInch :: Word -> Word
- dotPerInchToDotsPerMeter :: Word -> Word
- dotsPerCentiMeterToDotPerInch :: Word -> Word
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.
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 writingExif
Exif tag and associated data.
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 |
data Value
Encode values for unknown information
data Elem k
Element describing a metadata and it's (typed) associated value.
data SourceFormat
Type describing the original file format of the ilfe.
Functions
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.
Folding
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
Conversion functions
dotsPerMeterToDotPerInch :: Word -> Word
Conversion from dpm to dpi
dotPerInchToDotsPerMeter :: Word -> Word
Conversion from dpi to dpm
dotsPerCentiMeterToDotPerInch :: Word -> Word
Conversion dpcm -> dpi