Constructor

VipsImagejpegload

Declaration [src] 

int
vips_jpegload (
  const char* filename,
  VipsImage** out,
  ...
)

Description [src]

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, VipsFailOn.

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().

Optional arguments

  • shrink: gint, shrink by this much on load
  • fail_on: VipsFailOn, types of read error to fail on
  • autorotate: gboolean, use exif Orientation tag to rotate the image during load

See also

vips_jpegload_buffer(), vips_autorot().

This method 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 data, and is responsible for freeing it.
...

Type: 

NULL-terminated list of optional named arguments.

Return value

Type: int

0 on success, -1 on error.