Top |
VipsAccess | access | Read / Write |
gboolean | disc | Read / Write |
VipsForeignFlags | flags | Read / Write |
VipsImage * | out | Read / Write |
gboolean | sequential | Read / Write |
VipsArrayDouble * | background | Read / Write |
VipsImage * | in | Read / Write |
gboolean | strip | Read / Write |
enum | VipsForeignFlags |
enum | VipsSaveable |
enum | VipsForeignTiffCompression |
enum | VipsForeignTiffPredictor |
enum | VipsForeignTiffResunit |
enum | VipsForeignPngFilter |
enum | VipsForeignDzLayout |
enum | VipsForeignDzDepth |
enum | VipsForeignDzContainer |
GObject ╰── VipsObject ╰── VipsOperation ├── VipsForeign │ ├── VipsForeignLoad │ ╰── VipsForeignSave ╰── VipsForeign ├── VipsForeignLoad ╰── VipsForeignSave
This set of operations load and save images in a variety of formats.
The operations share a base class that offers a simple way to search for a
subclass of VipsForeign which can load a certain file (see
vips_foreign_find_load()
) or buffer (see vips_foreign_find_load_buffer()
),
or which could be used to save an image to a
certain file type (see vips_foreign_find_save()
and
vips_foreign_find_save_buffer()
). You can then run these
operations using vips_call()
and friends to perform the load or save.
vips_image_write_to_file() and vips_image_new_from_file()
and friends use
these functions to automate file load and save.
You can also invoke the operations directly, for example:
vips_tiffsave (my_image, "frank.anything", "compression", VIPS_FOREIGN_TIFF_COMPRESSION_JPEG, NULL);
To add support for a new file format to vips, simply define a new subclass of VipsForeignLoad or VipsForeignSave.
If you define a new operation which is a subclass of VipsForeign, support
for it automatically appears in all VIPS user-interfaces. It will also be
transparently supported by vips_image_new_from_file()
and friends.
VIPS comes with VipsForeign for TIFF, JPEG, PNG, Analyze, PPM, OpenEXR, CSV, Matlab, Radiance, RAW, FITS, WebP and VIPS. It also includes import filters which can load with libMagick and with OpenSlide.
void * vips_foreign_map (const char *base
,VipsSListMap2Fn fn
,void *a
,void *b
);
Apply a function to every VipsForeignClass that VIPS knows about. Foreigns are presented to the function in priority order.
Like all VIPS map functions, if fn
returns NULL
, iteration continues. If
it returns non-NULL
, iteration terminates and that value is returned. The
map function returns NULL
if all calls return NULL
.
See also: vips_slist_map()
.
const char *
vips_foreign_find_load (const char *filename
);
Searches for an operation you could use to load filename
. Any trailing
options on filename
are stripped and ignored.
See also: vips_foreign_find_load_buffer()
, vips_image_new_from_file()
.
const char * vips_foreign_find_load_buffer (void *data
,size_t size
);
Searches for an operation you could use to load a memory buffer.
See also: vips_image_new_from_buffer()
.
VipsForeignFlags vips_foreign_flags (const char *loader
,const char *filename
);
Return the flags for filename
using loader
.
loader
is something like "tiffload" or "VipsForeignLoadTiff".
gboolean vips_foreign_is_a (const char *loader
,const char *filename
);
Return TRUE
if filename
can be loaded by loader
. loader
is something
like "tiffload" or "VipsForeignLoadTiff".
const char *
vips_foreign_find_save (const char *filename
);
Searches for an operation you could use to write to filename
.
Any trailing options on filename
are stripped and ignored.
See also: vips_foreign_find_save_buffer()
, vips_image_write_to_file()
.
const char *
vips_foreign_find_save_buffer (const char *suffix
);
Searches for an operation you could use to write to a buffer in suffix
format.
See also: vips_image_write_to_buffer()
.
int vips_openslideload (const char *filename
,VipsImage **out
,...
);
Optional arguments:
level
: load this level
associated
: load this associated image
autocrop
: crop to image bounds
Read a virtual slide supported by the OpenSlide library into a VIPS image. OpenSlide supports images in Aperio, Hamamatsu, MIRAX, Sakura, Trestle, and Ventana formats.
To facilitate zooming, virtual slide formats include multiple scaled-down
versions of the high-resolution image. These are typically called
"levels". By default, vips_openslideload()
reads the highest-resolution
level (level 0). Set level
to the level number you want.
In addition to the slide image itself, virtual slide formats sometimes
include additional images, such as a scan of the slide's barcode.
OpenSlide calls these "associated images". To read an associated image,
set associated
to the image's name.
A slide's associated images are listed in the
"slide-associated-images" metadata item.
The output of this operator is always RGBA.
See also: vips_image_new_from_file()
.
int vips_jpegload (const char *filename
,VipsImage **out
,...
);
Optional arguments:
shrink
: shrink by this much on load
fail
: fail on warnings
autorotate
: use exif Orientation tag to rotate the image 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.
Setting fail
to TRUE
makes the JPEG reader fail on any warnings.
This can be useful for detecting truncated files, for example. Normally
reading these produces a warning, but no fatal error.
Setting autorotate
to TRUE
will make the loader interpret the EXIF
Orientation field and automatically rotate the image appropriately during
load. After rotation, the Orientation tag will be removed to prevent
accidental double-rotation.
Using autorotate
can be much slower than doing the rotate later
in processing. See vips_autorot()
.
Example:
vips_jpegload( "fred.jpg", &out, "shrink", 8, "fail", TRUE, 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
("icc-profile-data"). 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
("exif-data"), IPCT as
VIPS_META_IPCT_NAME
("ipct-data"), and XMP as VIPS_META_XMP_NAME
("xmp-data").
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 EXIF thumbnail, if present, is attached to the image as
"jpeg-thumbnail-data". See vips_image_get_blob()
.
This function only reads the image header and does not decompress any pixel data. Decompression only occurs when pixels are accessed.
See also: vips_jpegload_buffer()
, vips_image_new_from_file()
.
int vips_jpegload_buffer (void *buf
,size_t len
,VipsImage **out
,...
);
Optional arguments:
shrink
: shrink by this much on load
fail
: fail on warnings
Read a JPEG-formatted memory block into a VIPS image. Exactly as
vips_jpegload()
, but read from a memory buffer.
See also: vips_jpegload()
.
int vips_jpegsave (VipsImage *in
,const char *filename
,...
);
Optional arguments:
Q
: quality factor
profile
: attach this ICC profile
optimize_coding
: compute optimal Huffman coding tables
interlace
: write an interlaced (progressive) jpeg
strip
: remove all metadata from image
no
-subsample: disable chroma subsampling
Write a VIPS image to a file as JPEG.
Use Q
to set the JPEG compression factor. Default 75.
Use profile
to give the filename of a profile to be embedded in the JPEG.
This does not affect the pixels which are written, just the way
they are tagged. You can use the special string "none" to mean
"don't attach a profile".
If no profile is specified and the VIPS header contains an ICC profile named VIPS_META_ICC_NAME ("icc-profile-data"), the profile from the VIPS header will be attached.
The image is automatically converted to RGB, Monochrome or CMYK before saving.
EXIF data is constructed from VIPS_META_EXIF_NAME
("exif-data"), then
modified with any other related tags on the image before being written to
the file.
IPCT as VIPS_META_IPCT_NAME
("ipct-data") and XMP as VIPS_META_XMP_NAME
("xmp-data") are coded and attached.
If optimize_coding
is set, the Huffman tables are optimised. This is
sllightly slower and produces slightly smaller files.
If interlace
is set, the jpeg files will be interlaced (progressive jpeg,
in jpg parlance). These files may be better for display over a slow network
conection, but need much more memory to encode and decode.
If strip
is set, no EXIF data, IPCT data, ICC profile or XMP metadata is
written into the output file.
If no
-subsample is set, chrominance subsampling is disabled. This will
improve quality at the cost of larger file size. Useful for high Q factors.
See also: vips_jpegsave_buffer()
, vips_image_write_to_file()
.
int vips_jpegsave_buffer (VipsImage *in
,void **buf
,size_t *len
,...
);
Optional arguments:
Q
: JPEG quality factor
profile
: attach this ICC profile
optimize_coding
: compute optimal Huffman coding tables
interlace
: write an interlaced (progressive) jpeg
strip
: remove all metadata from image
no
-subsample: disable chroma subsampling
As vips_jpegsave()
, but save to a memory buffer.
The address of the buffer is returned in obuf
, the length of the buffer in
olen
. You are responsible for freeing the buffer with g_free()
when you
are done with it.
See also: vips_jpegsave()
, vips_image_write_to_file()
.
int vips_jpegsave_mime (VipsImage *in
,...
);
Optional arguments:
Q
: JPEG quality factor
profile
: attach this ICC profile
optimize_coding
: compute optimal Huffman coding tables
strip
: remove all metadata from image
no
-subsample: disable chroma subsampling
As vips_jpegsave()
, but save as a mime jpeg on stdout.
See also: vips_jpegsave()
, vips_image_write_to_file()
.
int vips_webpload (const char *filename
,VipsImage **out
,...
);
Optional arguments:
Read a webp file into a VIPS image.
See also:
int vips_webpload_buffer (void *buf
,size_t len
,VipsImage **out
,...
);
See also:
int vips_webpsave (VipsImage *in
,const char *filename
,...
);
Optional arguments:
Q
: quality factor
See also:
int vips_webpsave_buffer (VipsImage *in
,void **buf
,size_t *len
,...
);
Optional arguments:
Q
: JPEG quality factor
See also:
int vips_webpsave_mime (VipsImage *in
,...
);
Optional arguments:
Q
: quality factor
See also:
int vips_tiffload (const char *filename
,VipsImage **out
,...
);
Optional arguments:
page
: int, load this page
Read a TIFF file into a VIPS image. It is a full baseline TIFF 6 reader, with extensions for tiled images, multipage images, LAB colour space, pyramidal images and JPEG compression. including CMYK and YCbCr.
page
means load this page from the file. By default the first page (page
0) is read.
Any ICC profile is read and attached to the VIPS image. Any XMP metadata is read and attached to the image.
See also: vips_image_new_from_file()
.
int vips_tiffload_buffer (void *buf
,size_t len
,VipsImage **out
,...
);
Optional arguments:
page
: load this page
Read a TIFF-formatted memory block into a VIPS image. Exactly as
vips_tiffload()
, but read from a memory source.
See also: vips_tiffload()
.
int vips_tiffsave (VipsImage *in
,const char *filename
,...
);
Optional arguments:
compression
; use this compression scheme
Q
: quality factor
predictor
; compress with this prediction
profile
: attach this ICC profile
tile
; set TRUE
to write a tiled tiff
tile_width
; set tile size
tile_height
; set tile size
pyramid
; set TRUE
to write an image pyramid
squash
; squash 8-bit images down to 1 bit
resunit
; convert resolution to pixels per inch or cm during write
xres
; horizontal resolution in pixels/mm
yres
; vertical resolution in pixels/mm
bigtiff
; write a BigTiff file
Write a VIPS image to a file as TIFF.
Use compression
to set the tiff compression. Currently jpeg, packbits,
fax4, lzw, none and deflate are supported. The default is no compression.
JPEG compression is a good lossy compressor for photographs, packbits is
good for 1-bit images, and deflate is the best lossless compression TIFF
can do. LZW has patent problems and is no longer recommended.
Use Q
to set the JPEG compression factor. Default 75.
Use predictor
to set the predictor for lzw and deflate compression.
Predictor is not set by default. There are three predictor values recognised at the moment (2007, July): 1 is no prediction, 2 is a horizontal differencing and 3 is a floating point predictor. Refer to the libtiff specifications for further discussion of various predictors. In short, predictor helps to better compress image, especially in case of digital photos or scanned images and bit depths > 8. Try it to find whether it works for your images.
Use profile
to give the filename of a profile to be embedded in the TIFF.
This does not affect the pixels which are written, just the way
they are tagged. You can use the special string "none" to mean
"don't attach a profile".
If no profile is specified and the VIPS header contains an ICC profile named VIPS_META_ICC_NAME ("icc-profile-data"), the profile from the VIPS header will be attached.
Set tile
to TRUE to write a tiled tiff. By default tiff are written in
strips. Use tile_width
and tile_height
to set the tile size. The defaiult
is 128 by 128.
Set pyramid
to write the image as a set of images, one per page, of
decreasing size.
Set squash
to make 8-bit uchar images write as 1-bit TIFFs with zero
pixels written as 0 and non-zero as 1.
Use resunit
to override the default resolution unit.
The default
resolution unit is taken from the header field "resolution-unit"
(VIPS_META_RESOLUTION_UNIT in C). If this field is not set, then
VIPS defaults to cm.
Use xres
and yres
to override the default horizontal and vertical
resolutions. By default these values are taken from the VIPS image header.
libvips resolution is always in pixels per millimetre.
Set bigtiff
to attempt to write a bigtiff.
Bigtiff is a variant of the TIFF
format that allows more than 4GB in a file.
If in
has a field called VIPS_META_XMP_NAME ("xmp-data") it is written to
the tiff image.
See also: vips_tiffload()
, vips_image_write_to_file()
.
int vips_openexrload (const char *filename
,VipsImage **out
,...
);
Read a OpenEXR file into a VIPS image.
The reader can handle scanline and tiled OpenEXR images. It can't handle OpenEXR colour management, image attributes, many pixel formats, anything other than RGBA.
This reader uses the rather limited OpenEXR C API. It should really be redone in C++.
See also: vips_image_new_from_file()
.
int vips_fitsload (const char *filename
,VipsImage **out
,...
);
Read a FITS image file into a VIPS image.
This operation can read images with up to three dimensions. Any higher dimensions must be empty.
It can read 8, 16 and 32-bit integer images, signed and unsigned, float and double.
FITS metadata is attached with the "fits-" prefix.
See also: vips_image_new_from_file()
.
int vips_fitssave (VipsImage *in
,const char *filename
,...
);
Write a VIPS image to a file in FITS format.
See also: vips_image_write_to_file()
.
int vips_analyzeload (const char *filename
,VipsImage **out
,...
);
Load an Analyze 6.0 file. If filename
is "fred.img", this will look for
an image header called "fred.hdr" and pixel data in "fred.img". You can
also load "fred" or "fred.hdr".
Images are loaded lazilly and byte-swapped, if necessary. The Analyze metadata is read and attached.
See also: vips_image_new_from_file()
.
int vips_rawload (const char *filename
,VipsImage **out
,int width
,int height
,int bands
,...
);
Optional arguments:
offset
: offset in bytes from start of file
This operation mmaps the file, setting out
so that access to that
image will read from the file.
out
will be a 8-bit uchar image with bands
image bands, so bands
can
be thought of as meaning "number of bytes per pixel". Use functions
like vips_copy()
to set the exact band format, number of bands, byte
ordering and so on.
See also: vips_image_new_from_file()
.
int vips_rawsave (VipsImage *in
,const char *filename
,...
);
Writes the pixels in in
to the file filename
with no header or other
metadata.
See also: vips_image_write_to_file()
.
int vips_rawsave_fd (VipsImage *in
,int fd
,...
);
Writes the pixels in in
to the fd
with no header or other
metadata. Handy for implementing other savers.
See also: vips_rawsave()
.
int vips_csvload (const char *filename
,VipsImage **out
,...
);
Optional arguments:
skip
: skip this many lines at start of file
lines
: read this many lines from file
whitespace
: set of whitespace characters
separator
: set of separator characters
Load a CSV (comma-separated values) file. The output image is always 1 band (monochrome), VIPS_FORMAT_DOUBLE.
Items in lines can be either floating point numbers in the C locale, or
strings enclosed in double-quotes ("), or empty.
You can use a backslash()
within the quotes to escape special characters,
such as quote marks.
The reader is deliberately rather fussy: it will fail if there are any short lines, or if the file is too short. It will ignore lines that are too long.
skip
sets the number of lines to skip at the start of the file.
Default zero.
lines
sets the number of lines to read from the file. Default -1,
meaning read all lines to end of file.
whitespace
sets the skippable whitespace characters.
Default space.
Whitespace characters are always run together.
separator
sets the characters that separate fields.
Default ;,tab. Separators are never run together.
See also: vips_image_new_from_file()
.
int vips_csvsave (VipsImage *in
,const char *filename
,...
);
Optional arguments:
separator
: separator string
Writes the pixels in in
to the filename
as CSV (comma-separated values).
The image is written
one line of text per scanline. Complex numbers are written as
"(real,imaginary)" and will need extra parsing I guess. Only the first band
is written.
separator
gives the string to use to separate numbers in the output.
The default is "\t" (tab).
See also: vips_image_write_to_file()
.
int vips_matrixload (const char *filename
,VipsImage **out
,...
);
Reads a matrix from a file.
Matrix files have a simple format that's supposed to be easy to create with a text editor or a spreadsheet.
The first line has four numbers for width, height, scale and offset (scale and offset may be omitted, in which case they default to 1.0 and 0.0). Scale must be non-zero. Width and height must be positive integers. The numbers are separated by any mixture of spaces, commas, tabs and quotation marks ("). The scale and offset fields may be floating-point, and must use '.' as a decimal separator.
Subsequent lines each hold one line of matrix data, with numbers again separated by any mixture of spaces, commas, tabs and quotation marks ("). The numbers may be floating-point, and must use '.' as a decimal separator.
Extra characters at the ends of lines or at the end of the file are ignored.
See also: vips_csvload()
.
int vips_matrixsave (VipsImage *in
,const char *filename
,...
);
Write in
to filename
in matrix format. See vips_matrixload()
for a
description of the format.
See also: vips_matrixload()
.
int vips_matrixprint (VipsImage *in
,...
);
Print in
to stdout
in matrix format. See vips_matrixload()
for a
description of the format.
See also: vips_matrixload()
.
int vips_magickload (const char *filename
,VipsImage **out
,...
);
Optional arguments:
all_frames
: gboolean
, load all frames in sequence
density
: string, canvas resolution for rendering vector formats like SVG
Read in an image using libMagick, the ImageMagick library. This library can read more than 80 file formats, including SVG, BMP, EPS, DICOM and many others. The reader can handle any ImageMagick image, including the float and double formats. It will work with any quantum size, including HDR. Any metadata attached to the libMagick image is copied on to the VIPS image.
The reader should also work with most versions of GraphicsMagick. See the "--with-magickpackage" configure option.
Normally it will only load the first image in a many-image sequence (such
as a GIF). Set all_frames
to true to read the whole image sequence.
density
is "WxH" in DPI, e.g. "600x300" or "600" (default is "72x72"). See
the density
docs
on the imagemagick website.
See also: vips_image_new_from_file()
.
int vips_pngload (const char *filename
,VipsImage **out
,...
);
Optional arguments:
Read a PNG file into a VIPS image. It can read all png images, including 8- and 16-bit images, 1 and 3 channel, with and without an alpha channel.
Any ICC profile is read and attached to the VIPS image.
See also: vips_image_new_from_file()
.
int vips_pngload_buffer (void *buf
,size_t len
,VipsImage **out
,...
);
Read a PNG-formatted memory block into a VIPS image. It can read all png images, including 8- and 16-bit images, 1 and 3 channel, with and without an alpha channel.
Any ICC profile is read and attached to the VIPS image.
Caution: on return only the header will have been read, the pixel data is
not decompressed until the first pixel is read. Therefore you must not free
buf
until you have read pixel data from out
.
See also: vips_pngload()
.
int vips_pngsave (VipsImage *in
,const char *filename
,...
);
Optional arguments:
compression
: compression level
interlace
: interlace image
profile
: ICC profile to embed
filter
: VipsForeignPngFilter row filter flag(s)
Write a VIPS image to a file as PNG.
compression
means compress with this much effort (0 - 9). Default 6.
Set interlace
to TRUE
to interlace the image with ADAM7
interlacing. Beware
than an interlaced PNG can be up to 7 times slower to write than a
non-interlaced image.
Use profile
to give the filename of a profile to be embedded in the PNG.
This does not affect the pixels which are written, just the way
they are tagged. You can use the special string "none" to mean
"don't attach a profile".
If profile
is specified and the VIPS header
contains an ICC profile named VIPS_META_ICC_NAME ("icc-profile-data"), the
profile from the VIPS header will be attached.
Use filter
to specify one or more filters (instead of adaptive filtering),
see VipsForeignPngFilter.
The image is automatically converted to RGB, RGBA, Monochrome or Mono + alpha before saving. Images with more than one byte per band element are saved as 16-bit PNG, others are saved as 8-bit PNG.
See also: vips_image_new_from_file()
.
int vips_pngsave_buffer (VipsImage *in
,void **buf
,size_t *len
,...
);
Optional arguments:
compression
: compression level
interlace
: interlace image
profile
: ICC profile to embed
filter
: libpng row filter flag(s)
As vips_pngsave()
, but save to a memory buffer.
The address of the buffer is returned in obuf
, the length of the buffer in
olen
. You are responsible for freeing the buffer with g_free()
when you
are done with it.
See also: vips_pngsave()
, vips_image_write_to_file()
.
int vips_ppmload (const char *filename
,VipsImage **out
,...
);
Read a PPM/PBM/PGM/PFM file into a VIPS image.
It can read 1, 8, 16 and 32 bit images, colour or monochrome, stored in binary or in ASCII. One bit images become 8 bit VIPS images, with 0 and 255 for 0 and 1.
See also: vips_image_new_from_file()
.
int vips_ppmsave (VipsImage *in
,const char *filename
,...
);
Optional arguments:
ascii
: save as ASCII rather than binary
squash
: squash 8-bit images down to one bit
Write a VIPS image to a file as PPM. It can write 1, 8, 16 or 32 bit unsigned integer images, float images, colour or monochrome, stored as binary or ASCII. Integer images of more than 8 bits can only be stored in ASCII.
When writing float (PFM) images the scale factor is set from the "pfm-scale" metadata.
Set ascii
to TRUE
to write as human-readable ASCII. Normally data is
written in binary.
Set squash
to TRUE
to squash 8-bit images down to one bit. The saver does
no dithering, that's up to you.
See also: vips_image_write_to_file()
.
int vips_matload (const char *filename
,VipsImage **out
,...
);
Read a Matlab save file into a VIPS image.
This operation searches the save file for the first array variable with between 1 and 3 dimensions and loads it as an image. It will not handle complex images. It does not handle sparse matrices.
See also: vips_image_new_from_file()
.
int vips_radload (const char *filename
,VipsImage **out
,...
);
Read a Radiance (HDR) file into a VIPS image.
Radiance files are read as VIPS_CODING_RAD. They have one byte for each of
red, green and blue, and one byte of shared exponent. Some operations (like
vips_extract_area()
) can work directly with images in this format, but
mmany (all the arithmetic operations, for example) will not. Unpack
VIPS_CODING_RAD images to 3 band float with vips_rad2float()
if
you want to do arithmetic on them.
This operation ignores some header fields, like VIEW and DATE. It will not rotate/flip as the FORMAT string asks.
Sections of this reader from Greg Ward and Radiance with kind permission.
See also: vips_image_new_from_file()
.
int vips_radsave (VipsImage *in
,const char *filename
,...
);
Write a VIPS image in Radiance (HDR) format.
Sections of this reader from Greg Ward and Radiance with kind permission.
See also: vips_image_write_to_file()
.
int vips_dzsave (VipsImage *in
,const char *name
,...
);
Optional arguments:
layout
; directory layout convention
suffix
: suffix for tile tiles
overlap
; set tile overlap
tile_size
; set tile size
background
: background colour
depth
: how deep to make the pyramid
centre
: centre the tiles
angle
: rotate the image by this much
container
: set container type
properties
: write a properties file
Save an image as a set of tiles at various resolutions. By default dzsave
uses DeepZoom layout -- use layout
to pick other conventions.
vips_dzsave() creates a directory called name
to hold the tiles. If name
ends .zip
, vips_dzsave()
will create a zip file called name
to hold the
tiles. You can use container
to force zip file output.
You can set suffix
to something like ".jpg[Q=85]"
to control the tile
write options.
In Google layout mode, edge tiles are expanded to tile_size
by tile_size
pixels. Normally they are filled with white, but you can set another colour
with background
. Images are usually placed at the top-left of the tile,
but you can have them centred by turning on centre
.
You can set the size and overlap of tiles with tile_size
and overlap
.
They default to the correct settings for the selected layout
.
Use depth
to control how low the pyramid goes. This defaults to the
correct setting for the layout
you select.
If properties
is TRUE
, vips_dzsave()
will write a file called
vips-properties.xml
to the output directory. This file lists all of the
metadata attached to in
in an obvious manner. It can be useful for viewing
programs which wish to use fields from source files loaded via
vips_openslideload()
.
See also: vips_tiffsave()
.
Some hints about the image loader.
VIPS_FOREIGN_PARTIAL
means that the image can be read directly from the
file without needing to be unpacked to a temporary image first.
VIPS_FOREIGN_SEQUENTIAL
means that the loader supports lazy reading, but
only top-to-bottom (sequential) access. Formats like PNG can read sets of
scanlines, for example, but only in order.
If neither PARTIAL or SEQUENTIAL is set, the loader only supports whole image read. Setting both PARTIAL and SEQUENTIAL is an error.
VIPS_FOREIGN_BIGENDIAN
means that image pixels are most-significant byte
first. Depending on the native byte order of the host machine, you may
need to swap bytes. See vips_copy()
.
The compression types supported by the tiff writer.
Use Q
to set the jpeg compression level, default 75.
Use prediction
to set the lzw or deflate prediction, default none.
The predictor can help deflate and lzw compression. The values are fixed by the tiff library.
http://www.w3.org/TR/PNG-Filters.html The values mirror those of png.h in libpng.
“access”
property“access” VipsAccess
Required access pattern for this file.
Flags: Read / Write
Default value: VIPS_ACCESS_RANDOM
“sequential”
property “sequential” gboolean
Sequential read only.
Flags: Read / Write
Default value: FALSE