Re: [Ocaml-lib-devel] IO Bits API

[Nicolas C. <war...@fr...>]

> On Thu, May 19, 2005 at 04:34:19PM +0900, Nicolas Cannasse wrote:
> > I also have a complete, small, and easy Png library, that can be used
> > together with Unzip module to read Png using only ExtLib. If there is
some
> > interest it could be added to ExtLib.
>
> A Png library sounds nice, but I'm not sure how appropriate it is for
> Extlib.  How does it compare to the functionality of camlimages?
>
> Rich.

It's maybe more easy to use than a framework such as camlimages, and is pure
Ocaml (it doesn't require additionnal decoding libraries).
Here's the mli for review. The full ML source is only 11Ko.

Nicolas

---

type grey_bits =
| GBits1
| GBits2
| GBits4
| GBits8
| GBits16

type grey_alpha_bits =
| GABits8
| GABits16

type true_bits =
| TBits8
| TBits16

type index_bits =
| IBits1
| IBits2
| IBits4
| IBits8

type alpha =
| NoAlpha
| HaveAlpha

type color =
| ClGreyScale of grey_bits
| ClGreyAlpha of grey_alpha_bits
| ClTrueColor of true_bits * alpha
| ClIndexed of index_bits

type header = {
  png_width : int;
  png_height : int;
  png_color : color;
  png_interlace : bool;
}

type chunk_id = string

type chunk =
| CEnd
| CHeader of header
| CData of string
| CPalette of string
| CUnknown of chunk_id * string

type png = chunk list

type error_msg =
| Invalid_header
| Invalid_file
| Truncated_file
| Invalid_CRC
| Invalid_colors
| Unsupported_colors
| Invalid_datasize
| Invalid_filter of int
| Invalid_array

exception Error of error_msg

val error_msg : error_msg -> string

val is_critical : chunk_id -> bool
val is_public : chunk_id -> bool
val is_reseverd : chunk_id -> bool
val is_safe_to_copy : chunk_id -> bool

val header : png -> header

val data : png -> string

val color_bits : color -> int

val parse : IO.input -> png

val write : 'a IO.output -> png -> unit

val filter : png -> string -> string

val make : width:int -> height:int -> pixel:(int -> int -> int32) ->
compress:(string -> string) -> png