exception Out_of_image
exception for illegal point access
exception Wrong_image_type
exception for illegal internal image type
exception Wrong_file_type
exception for unsupported image FILE format
type t = | Index8 of Index8.t | Rgb24 of Rgb24.t | Index16 of Index16.t | Rgba32 of Rgba32.t | Cmyk32 of Cmyk32.t
Generic image type
Colors: the copies of color.mli
type rgb = Color.rgb = { mutable r: int; mutable g: int; mutable b: int }
type rgba = Color.rgba = { color: rgb; mutable alpha: int }
type cmyk = Color.cmyk =
{ mutable c : int; mutable m : int; mutable y : int; mutable k : int }
type map = Color.map = {
mutable max: int;
maximum number allowed in the color map (-1 = unlimited)
: rgb array }
Image formats
type format = | Gif | Bmp | Jpeg | Tiff | Png | Xpm | Ppm | Ps ;;
functions for filename extensions
val extension : format -> string
returns the corresponding extension "gif", "bmp" etc. for given format
val guess_format : string -> format
returns the image format guessed from the file extension of a given file name
val get_extension : string -> string * string
val guess_extension : string -> format
type colormodel = Info.colormodel = | Gray | RGB | Index | GrayA | RGBA ;;
Infos attached to bitmaps
type info = Info.info = | Info_DPI of float (* dot per inch *) | Info_BigEndian | Info_LittleEndian (* endianness of image file *) | Info_ColorModel of colormodel (* color model of image file *) | Info_Depth of int (* Image bit depth *) | Info_Corrupted (* For corrupted PNG files *) ;;
val dpi : info list -> float option
Image file header
type header = {
header_width : int;
header_height : int;
header_infos : info list
}
;;
val file_format : string -> format * header
file_format filename reads the header of image file filename
and returns its format and some useful information found in the
header (ex. width, height). file_format does not read image
contents, but just quickly returns file header information.
file_format does not depend on any external libraries
Load options
type load_option = | Load_Progress of (float -> unit) (* For progress meters *) | Load_Resolution of float * float (* Pixel/Inch for rasterization of PS *) ;;
Save options
type save_option = | Save_Quality of int (* Save quality for Jpeg compression *) | Save_Progress of (float -> unit) (* For progress meters *) | Save_Interlace (* Interlaced Gif *) ;;
val load_progress : load_option list -> (float -> unit) option
val load_resolution : load_option list -> (float * float) option
val save_progress : save_option list -> (float -> unit) option
val save_interlace : save_option list -> bool
val save_quality : save_option list -> int option
type format_methods = {
check_header: (string -> header);
load: (string -> load_option list -> t) option;
save: (string -> save_option list -> t -> unit) option;
}
val add_methods : format -> format_methods -> unit
If you write new drivers for some image format, use this function to register their loading/saving functions into the libaray
val load : string -> load_option list -> t
load filename options read the header of an image file filename,
loads the image by calling corresponding loading method, and
returns it. If the file format is not supported by the library,
a Wrong_file_type exception will be raised. You can specify loading
options in options such as progressive meter function.
val save : string -> format -> save_option list -> t -> unit
save filename format options image saves image into
a file filename in the format format. You can specify
some saving parameters options. Some options are specific
to some image formats and do not work with the others.
val size : t -> int * int
Returns size (width and height) of image
val destroy : t -> unit
Free the image. If you turn on image swapping (see bitmap.mli), you need to call this function explicitly to tell the library that this image is no longer used.
val blit : t -> int -> int -> t -> int -> int -> int -> int -> unit
blit src sx sy dst dx dy width height copies the rectangle
region of src at (sx,sy)-(sx+width-1,sy+height-1) to dst, at
(dx,dy)-(dx+width-1,dy+height-1)
Each image representation module must contain these types and functions, at least
module
type T = sig
type t
type elt val create : int -> int -> t
create width height creates an image of the size (width x height)
val destroy : t -> unit
destroy image frees the memory and swap files of image
You have to call this function explicitly if you turn on
image swapping (See bitmap.mli).
val get : t -> int -> int -> elt val set : t -> int -> int -> elt -> unit
get image x y and set image x y v reads/writes the pixel
information at (x,y) of image. If (x,y) is out of the image,
they raise Out_of_image exception.
val unsafe_get : t -> int -> int -> elt val unsafe_set : t -> int -> int -> elt -> unit
unsafe_get and unsafe_set are the same functions as get
and set, but they lack the image region checks. So it is fast.
But you have to use them with being sure that the specified point
is in the image. Otherwise the result is unknown, and sometimes
a runtime error occurs.
val sub : t -> int -> int -> int -> int -> t
sub dst x y width height returns sub-bitmap of dst,
at (x,y)-(x+width-1,y+height-1).
val blit : t -> int -> int -> t -> int -> int -> int -> int -> unit
blit src sx sy dst dx dy width height copies the rectangle
region of src at (sx,sy)-(sx+width-1,sy+height-1) to dst, at
(dx,dy)-(dx+width-1,dy+height-1)
end
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