Max Rabkin wrote:
Haskellers,
To add image support to fdo-notify, I need an image type. Looking through Hackage, I didn't find any image library with the following features: * Load from a variety of formats (at least PNG and JPG, I'd say) * Efficient per-pixel access, or a way to dump the image into a ByteString as a bitmap (I need to serialise them into the protocol's bitmap format) Preferably, it should be possible to construct images programmatically too.
Is there really no such library? It would be nice to have something like a Haskell equivalent of the Python Imaging Library, which is the de facto standard image library in Python and supports just about every type of operation on images you could ask for.
Regards, Max
Try AC-EasyRaster-GTK. It's a thin layer over Gtk2hs that I wrote precisely because it's so fiddly to do bitmapped graphics with Gtk2hs. (Vector graphics is delightfully easy with Cairo, but bitmap graphics requires manual bit-twiddling, and lots of simple but non-obvious API calls.) In particular, Easy Raster will trivially load and save PNG and JPEG images, and provide pixel-level read/write functions (either with or without bounds checks). What I haven't implemented is access to the underlying pixel array. There's a function ib_pixmap which will get you the GTK Pixmap object, from which you can obtain the pixel array. But it's not an IOArray or STArray or anything like that; it's some other datatype that implements the MArray class, so it doesn't buy you much. You might as well just use the pixel read/write functions from Easy Raster and manually iterate all pixels... (Another annoying quirk is that Gtk2hs doesn't provide a way to read or write an image from a handle, only from a real file, so naturally Easy Raster shares the same limitation.)