Constructor
VipsImagejpegload
Declaration [src]
int
vips_jpegload (
const char* filename,
VipsImage** out,
...
)
Description [src]
Optional arguments:
shrink
: %gint, shrink by this much on loadfail_on
:VipsFailOn
, types of read error to fail onautorotate
: %gboolean, rotate image upright during load
Read a JPEG file into a VIPS image. It can read most 8-bit JPEG images, including CMYK and YCbCr.
shrink
means shrink by this integer factor during load. Possible values
are 1, 2, 4 and 8. Shrinking during read is very much faster than
decompressing the whole image and then shrinking later.
Use fail_on
to set the type of error that will cause load to fail. By
default, loaders are permissive, that is, #VIPS_FAIL_ON_NONE.
Setting autorotate
to TRUE
will make the loader interpret the
orientation tag and automatically rotate the image appropriately during load.
If autorotate
is FALSE
, the metadata field #VIPS_META_ORIENTATION is set
to the value of the orientation tag. Applications may read and interpret
this field
as they wish later in processing. See vips_autorot(). Save
operations will use #VIPS_META_ORIENTATION, if present, to set the
orientation of output images.
Example:
vips_jpegload("fred.jpg", &out,
"shrink", 8,
"fail_on", VIPS_FAIL_ON_TRUNCATED,
NULL);
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
VIPS_META_ICC_NAME. You need to use something like
vips_icc_import()
to get CIE values from the file.
EXIF metadata is attached as #VIPS_META_EXIF_NAME, IPTC as
VIPS_META_IPTC_NAME, and XMP as #VIPS_META_XMP_NAME.
The int metadata item “jpeg-multiscan” is set to the result of jpeg_has_multiple_scans(). Interlaced jpeg images need a large amount of memory to load, so this field gives callers a chance to handle these images differently.
The string-valued field “jpeg-chroma-subsample” gives the chroma subsample in standard notation. 4:4:4 means no subsample, 4:2:0 means YCbCr with Cb and Cr subsampled horizontally and vertically, 4:4:4:4 means a CMYK image with no subsampling.
The EXIF thumbnail, if present, is attached to the image as “jpeg-thumbnail-data”. See vips_image_get_blob().
See also: vips_jpegload_buffer(), vips_image_new_from_file(), vips_autorot().
This constructor is not directly available to language bindings.
Parameters
filename
-
Type:
const char*
File to load.
The data is owned by the caller of the function. The value is a NUL terminated UTF-8 string. out
-
Type:
VipsImage
Decompressed image.
The argument will be set by the function. The caller of the function takes ownership of the returned data, and is responsible for freeing it. ...
-
Type:
NULL
-terminated list of optional named arguments.