2007-08-29 18:23:50 +02:00
|
|
|
.TH IM_JPEG2VIPS 3 "6 June 1994"
|
|
|
|
|
.SH NAME
|
|
|
|
|
im_jpeg2vips, im_vips2jpeg, im_vips2bufjpeg, im_vips2mimejpeg \- convert JPEG images to and from VIPS format
|
|
|
|
|
.SH SYNOPSIS
|
|
|
|
|
#include <vips/vips.h>
|
|
|
|
|
|
|
|
|
|
int im_jpeg2vips( char *filename, IMAGE *out )
|
|
|
|
|
|
|
|
|
|
int im_jpeg2vips_header( char *filename, IMAGE *out )
|
|
|
|
|
|
|
|
|
|
int im_vips2jpeg( IMAGE *in, char *filename )
|
|
|
|
|
|
|
|
|
|
int im_vips2bufjpeg( IMAGE *in, IMAGE *base, char **obuf, int *olen )
|
|
|
|
|
|
|
|
|
|
int im_vips2mimejpeg( IMAGE *in )
|
|
|
|
|
|
|
|
|
|
.SH DESCRIPTION
|
|
|
|
|
.B im_jpeg2vips()
|
|
|
|
|
reads the named jpeg file and writes it to the specified
|
2008-02-15 19:07:39 +01:00
|
|
|
IMAGE. The entire image is read before returning. It can read most 8-bit JPEG
|
|
|
|
|
images, including CMYK.
|
|
|
|
|
|
|
|
|
|
You can embed options in the filename. They have the form:
|
|
|
|
|
|
|
|
|
|
filename.jpg:<shrink-factor>
|
|
|
|
|
|
|
|
|
|
.B shrink-factor
|
|
|
|
|
will shrink the image by that factor during read. Allowed values are 1, 2, 4
|
|
|
|
|
and 8. Shrinking during read is very much faster than decompressing the whole
|
|
|
|
|
image and then shrinking. Example:
|
|
|
|
|
|
|
|
|
|
fred.jpg:8
|
|
|
|
|
|
|
|
|
|
will return fred.jpg shrink by a factor of 8.
|
2007-08-29 18:23:50 +02:00
|
|
|
|
|
|
|
|
Any embedded ICC profiles are ignored: you always just get the RGB from the
|
|
|
|
|
file. Instead, the embedded profile will be attached to the image as metadata.
|
|
|
|
|
Any EXIF data is also attached as VIPS metadata.
|
|
|
|
|
|
|
|
|
|
.B im_jpeg2vips_header()
|
|
|
|
|
reads just the header of the JPEG file (including any EXIF data), and sets
|
|
|
|
|
the fields in the VIPS image.
|
|
|
|
|
You can't read any pixels! This is only useful for printing header
|
|
|
|
|
information.
|
|
|
|
|
|
|
|
|
|
.B im_vips2jpeg()
|
|
|
|
|
writes the IMAGE to filename in JPEG format. It uses the
|
|
|
|
|
default settings of the IJG library.
|
|
|
|
|
|
|
|
|
|
A compression factor may be encoded in the filename: for example,
|
|
|
|
|
"fred.jpg" will write with the default compression factor (75),
|
|
|
|
|
"fred.jpg:25" will write with factor 25.
|
|
|
|
|
|
|
|
|
|
An ICC profile may also be specified. For example,
|
|
|
|
|
"fred.jpg:25,/home/john/srgb.icc" will embed the profile stored in the file
|
|
|
|
|
"/home/john/srgb.icc" into the JPEG image. This does not affect the pixels
|
|
|
|
|
which are written; just the way they are tagged.
|
|
|
|
|
|
|
|
|
|
If no profile is specified in the save string and the VIPS header contains an
|
|
|
|
|
ICC profile named IM_META_ICC_NAME ("icc-profile-data"), the
|
|
|
|
|
profile from the header will be attached.
|
|
|
|
|
|
|
|
|
|
The image is automatically converted to RGB or Monochrome before saving. Any
|
|
|
|
|
metadata attached to the image is saved as EXIF, if possible.
|
|
|
|
|
|
|
|
|
|
.B im_vips2bufjpeg()
|
|
|
|
|
returns the compressed image in a memory buffer. The buffer
|
|
|
|
|
is allocated for you, local to IMAGE descriptor
|
|
|
|
|
.B base.
|
|
|
|
|
The size of the
|
|
|
|
|
allocated buffer is returned in the
|
|
|
|
|
.B olen
|
|
|
|
|
parameter. You are responsible for
|
|
|
|
|
freeing the buffer. The buffer is only allocated if the function returns
|
|
|
|
|
successfully.
|
|
|
|
|
|
|
|
|
|
.B im_vips2mimejpeg()
|
|
|
|
|
writes the image to stdout as a MIME image/jpeg type. It
|
|
|
|
|
outputs Content-Length and Content-Type fields making the result suitable for
|
|
|
|
|
sending to a web browser.
|
|
|
|
|
|
|
|
|
|
.SH SEE ALSO
|
|
|
|
|
im_isjpeg(3).
|
