Re: Graphics hierarchy

27 Feb 2002


      At 2002-02-27 01:07, Ketil Z. Malde wrote:
...
-- probably elsewhere in the hierarchy
class FileFormat a where
       encode :: a -> [Word8]
       decode :: [Word8] -> a
instance FileFormat PNG where
       encode = ...
       decode = ..
I prefer ML-style structures/functors in this particular instance:

data FileFormat a = MkFileFormat
     {
     encodeFile :: a -> [Word8],
     decodeFile :: [Word8] -> Maybe a
     };

formatPNG :: (Image img) => FileFormat img;

formatJPEG :: (Image img) => JPEGCompressionFactor -> FileFormat img;

formatUTF8 :: FileFormat String;
...
class Image a where
       rotate :: a -> Int -> a
       scale :: a -> Int -> Int -> a
Maybe compose/blend images?  Altering alpha and gamma, color
manipulation?
Sounds like a serious project, with the possibility of plenty of 
complication.

-- 
Ashley Yakeley, Seattle WA