package camlimages
Install
Dune Dependency
Authors
Maintainers
Sources
sha256=1c9a68bdc3d348c9f859d490dadf384926213e47a584159832f7fc4a20242865
md5=1ddba74d210b86a899b5d6565f45c2dc
doc/camlimages.jpeg/Jpeg/index.html
Module Jpeg
1 JPEG markers
module Marker : sig ... end 1 Basic save/load
val load : string -> Images.load_option list -> Images.tLoads a jpeg image.
val load_thumbnail :
string ->
Images.load_option list ->
Geometry.spec ->
int * int * Images.tJPEG image data is composed so that thumbnails of the size 1/2, 1/4 and 1/8 of the original size can be loaded faster. load_thumnail loads an JPEG image with the one of these scales and 1/1 which is nearest and equal to or bigger than the given Gemetry.spec.
val save : string -> Images.save_option list -> Images.t -> unitSave a full-color image in jpeg format file. Raises Invalid_argument if the image is not a full-color image.
val save_with_markers :
string ->
Images.save_option list ->
Images.t ->
Marker.t list ->
unitSame as save but it also writes markers
val save_as_cmyk :
string ->
Images.save_option list ->
(Images.rgb -> int * int * int * int) ->
Images.t ->
unitSaves RGB24 image as a CMYK32 JPEG image, using the given color conversion function on the fly. More efficient than creating a CMYK24 image and saveing it.
val save_cmyk_sample : string -> Images.save_option list -> unitCreate CMYK jpeg image sample. Just for developpers.
Scanline based I/O functions
open_in path opens a JPEG image path and returns its width, height, a handle to get scanlines, and the JPEG makers.
val open_in_thumbnail :
string ->
Geometry.spec ->
int * int * (int * int * in_handle) * Marker.t listopen_in_thumbnail is the same as open_in but possibly scales down the image size based on the given Geometry.spec int the same way as load_thumbnail.
val read_scanline : in_handle -> bytes -> int -> unitread_scanline h buf off reads a scanline from the handle and store in bytes at the offset off. (image's width * bytes_per_pixel) bytes are overwritten from off of bytes. No size check of buf is performed.
val close_in : in_handle -> unitcloses the given scanline handle
val open_out : string -> int -> int -> int -> out_handleopen_out path width height quality opens a JPEG file at path, with width, height and quality. It returns a scanline handle for write.
val write_marker : out_handle -> Marker.t -> unitwrite_marker h m writes a maker to JPEG. It must be performed before calling write_scanline.
val write_scanline : out_handle -> bytes -> unitwrite_scanline h buf writes the contents of buf to the write handle. buf must have enough data for a scanline: (image's width * bytes_per_pixel) bytes of data must be available. No size check is performed.
val close_out : out_handle -> unitClose the write handle
Accessing the header information without touching the pixel data
val check_header : string -> Images.headerChecks the file header
val read_markers : string -> Marker.t listOpen the file, read the markers, then close it immediately.