mirror of
https://github.com/HDFGroup/hdf5.git
synced 2024-12-27 08:01:04 +08:00
1d680fe04c
* Fixed warnings and started H5Epublic.h.
* Include H5FD* headers to correctly resolve references.
* Doxygen2 (#330)
* H5Eauto_is_v2.
* Added a few more calls.
* Added a few more H5E calls.
* First cut of H5E v2.
* Added the deprecated v1 calls.
* Updated spacing.
* Once more.
* Taking some inspiration from Eigen3.
* Add doxygen for the assigned functions: H5Pregister1,H5Pinsert1,H5Pen… (#352)
* Add doxygen for the assigned functions: H5Pregister1,H5Pinsert1,H5Pencode1, H5Pget_filter_by_id1,H5Pget_version, H5Pset_file_space,H5Pget_file_space. Someone already adds H5Pget_filter1. Also fixs an extra parameter 'close' call back function for HPregister2.
* doxygen work. fixs format by using clang-format.
* doxgen work for H5Pregister1 etc. Addressed Barbara and Gerd's comments.
For Quincey's comments, since we are not supposed to change the source code.
I leave this to future improvements.
* added documentation for H5P APIs (#350)
* add documenation for H5Pget_buffer,H5Pget_data_transform,H5Pget_edc_check,H5Pget_hyper_vector_size,H5Pget_preserve,H5Pget_type_conv_cb,H5Pget_vlen_mem_manager,H5Pset_btree_ratios
* format corrections
* fixed grammer
* fixed herr_t
* Better name.
* A fresh look.
* add doxygen to H5Ppublic.h
* use attention instead of warning
* Add doxygen comments in H5Ppublic.h (#375)
* Add doxygen comments in H5Ppublic.h
* H5Pset_meta_block_size
* H5Pset_metadata_read_attempts
* H5Pset_multi_type
* H5Pset_object_flush_cb
* H5Pset_sieve_buf_size
* H5Pset_small_data_block_size
* H5Pset_all_coll_metadata_ops
* H5Pget_all_coll_metadata_ops
* Add DOXYGEN_EXAMPLES_DIR to src/CMakeLists.txt
* Fix clang-format errors
* Fix filenames in doxygen/examples
* add doxygen to H5Ppublic.h (#378)
* add doxygen to H5Ppublic.h
* use attention instead of warning
Co-authored-by: Kimmy Mu <kmu@hdfgroup.org>
* Revert "add doxygen to H5Ppublic.h (#378)"
This reverts commit 2ee1821b13.
* Updated Doxygen variables.
* I forgot to copy two images.
* Enable desktop search by default.
* Add my assigned Doxygen documentation.
* Remove whitespace at EOL. Appease clang-format.
* Addressed Chris' comments.
* Added an alias for asynchronous functions.
* One space is enough for all of us.
* Slightly restructured RM page.
* address some issues
* reformatting
* Style external links.
* reformatting
* reformatting
* Added "Metadata Caching in HDF5" as a technical note example.
* Revise this soon!
* Added specification examples.
* Fixed references.
* Added H5AC cache image stuff and file format study.
* Added older FMT versions. Where did 1.0 go?
* Updated C/C++ note and replaced ambiguous labels.
* Reformat source with clang v10.0.1.
* Added the VFL technical note.
* Added what I believe might be called version 1.0 of the format.
* Added the remaining specs.
* Added H5Z callback documentation and fixed a few mistakes.
* Added dox for deprecated H5G calls and fixed a few snippet blockIDs.
* clang-format happy?
* Ok?
* Bonus track: Deprecated H5D functions.
* Carry over the more detailed group description.
* Added documentation for the missing and deprecated H5R calls.
* Life is easier and less repetitive w/ snippets. Use them!
* Eliminate the snippet block ID artifacts in the HTML rendering.
* Fixed snippet HTML artifacts and added a few missing calls.
* Under 20 H5Ps to go!
* Almost complete!
* "This is a form of pedantry up with which I will not put." (Churchill)
* Let's not waste as much space on bulleted lists!
* First complete (?) draft of the Doxygen-based RM.
* Completeness check and minor fixes along the way.
* Pedantry.
* Adding missing H5FD calls checkpoint.
* Pedantry.
* More pedantry.
* Added H5Pset_fapl_log.
* First draft of H5ES.
* Fixed warnings.
* Prep. for map module.
* First cut of the map module.
* Pedantry.
* Possible H5F introduction.
* Fix the indentation.
* Pedantry.
* Ditto.
* Thanks to the reviewers for their comments.
* Added missing images.
* Line numbers are a distraction here.
* More examples, references, and clean-up. Don't repeat yourself!
* Clang pedantry.
* Ditto.
* More reviewer comments...
* Templatized references and cleaned up \todos.
* Committing clang-format changes
* Fixed MANIFEST.
* Addressed Quincey's comments. (OCPLs)
* Fixed a few more \todo items.
* Fixed more \todo items.
* Added attribute life cycle.
* Forgot the examples file.
* Committing clang-format changes
* Pedantry.
* Live and learn!
* Added a sample H5D life cycle.
* Committing clang-format changes
* Pedantry.
Co-authored-by: kyang2014 <kyang2014@users.noreply.github.com>
Co-authored-by: Scot Breitenfeld <brtnfld@hdfgroup.org>
Co-authored-by: Kimmy Mu <kmu@hdfgroup.org>
Co-authored-by: Christopher Hogan <ChristopherHogan@users.noreply.github.com>
Co-authored-by: jya-kmu <53388330+jya-kmu@users.noreply.github.com>
Co-authored-by: David Young <dyoung@hdfgroup.org>
Co-authored-by: Larry Knox <lrknox@hdfgroup.org>
Co-authored-by: github-actions <41898282+github-actions[bot]@users.noreply.github.com>
1204 lines
29 KiB
HTML
1204 lines
29 KiB
HTML
<!doctype html public "-//w3c//dtd html 4.0 transitional//en">
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<html>
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
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<meta name="GENERATOR" content="Mozilla/4.72 [en] (WinNT; U) [Netscape]">
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<title>Image Specification</title>
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The HDF5 specification defines the standard objects and storage for the
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standard HDF5 objects. (For information about the HDF5 library, model and
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specification, see the HDF documentation.) This document is an additional
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specification do define a standard profile for how to store image data
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in HDF5. Image data in HDF5 is stored as HDF5 datasets with standard attributes
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to define the properties of the image.
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<p>This specification is primarily concerned with two dimensional raster
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data similar to HDF4 Raster Images. Specifications for storing other
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types of imagery will be covered in other documents.
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<p>This specification defines:
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<ul>
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<li>
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Standard storage and attributes for an Image dataset (<a href="#Sect1">Section
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1</a>)</li>
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<li>
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Standard storage and attributes for Palettes (<a href="#sect2">Section
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2</a>)</li>
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<li>
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Standard for associating Palettes with Images. (<a href="#Sect3">Section
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3</a>)</li>
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</ul>
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<h2>
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<a NAME="Sect1"></a>1. HDF5 Image Specification</h2>
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<h3>
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1.1 Overview</h3>
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Image data is stored as an HDF5 dataset with values of HDF5 class Integer
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or Float. A common example would be a two dimensional dataset, with
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elements of class Integer, e.g., a two dimensional array of unsigned 8
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bit integers. However, this specification does not limit the dimensions
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or number type that may be used for an Image.
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<p>The dataset for an image is distinguished from other datasets by giving
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it an attribute "CLASS=IMAGE". In addition, the Image dataset may
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have an optional attribute "PALETTE" that is an array of object references
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for zero or more palettes. The Image dataset may have additional attributes
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to describe the image data, as defined in <a href="#Sect1.2">Section 1.2</a>.
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<p>A Palette is an HDF5 dataset which contains color map information.
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A Pallet dataset has an attribute "CLASS=PALETTE" and other attributes
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indicating the type and size of the palette, as defined in <a href="#sect2">Section
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2.1</a>. A Palette is an independent object, which can be shared
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among several Image datasets.
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<h3>
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<a NAME="Sect1.2"></a>1.2 Image Attributes</h3>
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The attributes for the Image are scalars unless otherwise noted.
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The length of String valued attributes should be at least the number of
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characters. Optionally, String valued attributes may be stored in a String
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longer than the minimum, in which case it must be zero terminated or null
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padded. "Required" attributes must always be used. "Optional" attributes
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must be used when required.
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<br>
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<h4>
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Attributes</h4>
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<dl>
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<dt>
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Attribute name="<b>CLASS</b>" (Required)</dt>
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<dd>
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This attribute is type H5T_C_S1, with size 5.</dd>
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<dd>
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For all Images, the value of this attribute is "IMAGE".</dd>
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<dd>
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</dd>
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<dd>
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This attribute identifies this data set as intended to be interpreted as
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an image that conforms to the specifications on this page.</dd>
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</dl>
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<dt>
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Attribute name="<b>PALETTE</b>"</dt>
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<dl>
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<dd>
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A Image dataset within an HDF5 file may optionally specify an array of
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palettes to be viewed with. The dataset will have an attribute field called
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"<b>PALETTE</b>" which contains a one-dimensional array of object reference
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pointers (HDF5 datatype H5T_STD_REF_OBJ) which refer to palettes in the
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file. The palette datasets must conform to the Palette specification in
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<a href="#sect2">section
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2 below</a>. The first palette in this array will be the default palette
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that the data may be viewed with.</dd>
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</dl>
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<dl>
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<dt>
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</dt>
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<dt>
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Attribute name="<b>IMAGE_SUBCLASS</b>"</dt>
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<dd>
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If present, the value of this attribute indicates the type of Palette that
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should be used with the Image. This attribute is a scalar of type
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H5T_C_S1, with size according to the string plus one. The values
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are:</dd>
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<dl>
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<dt>
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"IMAGE_GRAYSCALE" (length 15)</dt>
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<dd>
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A grayscale image</dd>
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<dt>
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"IMAGE_BITMAP" (length 12)</dt>
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<dd>
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A bit map image</dd>
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<dt>
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"IMAGE_TRUECOLOR" (length 15)</dt>
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<dd>
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A truecolor image</dd>
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<dt>
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"IMAGE_INDEXED" (length 13)</dt>
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<dd>
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An indexed image</dd>
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<dd>
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</dd>
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</dl>
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<dt>
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Attribute name="<b>INTERLACE_MODE</b>"</dt>
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<dd>
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For images with more than one component for each pixel, this optional attribute
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specifies the layout of the data. The values are type H5T_C_S1 of length
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15. See <a href="#Section1.3">section 1.3</a> for information about the
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storage layout for data.</dd>
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<dd>
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"INTERLACE_PIXEL" (default): the component value for a pixel are contiguous.</dd>
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<dd>
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"INTERLACE_PLANE": each component is stored as a plane.</dd>
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<dt>
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</dt>
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<dt>
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Attribute name="<b>DISPLAY_ORIGIN</b>"</dt>
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<dd>
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This optional attribute indicates the intended orientation of the data
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on a two-dimensional raster display. The value indicates which corner
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the pixel at (0, 0) should be viewed. The values are type H5T_C_S1
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of length 2. If DISPLAY_ORIGIN is not set, the orientation is undefined.</dd>
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<dd>
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"UL": (0,0) is at the upper left.</dd>
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<dd>
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"LL": (0,0) is at the lower left.</dd>
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<dd>
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"UR": (0,0) is at the upper right.</dd>
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<dd>
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"LR": (0,0) is at the lower right.</dd>
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</dl>
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<dt>
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Attribute name="<b>IMAGE_WHITE_IS_ZERO</b>"</dt>
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<dl>
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<dd>
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This attribute is of type H5T_NATIVE_UCHAR. 0 = false, 1 = true .
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This is used for images with IMAGE_SUBCLASS="IMAGE_GRAYSCALE" or "IMAGE_BITMAP".</dd>
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</dl>
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<dl>
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<dt>
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Attribute name="<b>IMAGE_MINMAXRANGE</b>"</dt>
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<dd>
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If present, this attribute is an array of two numbers, of the same HDF5
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datatype as the data. The first element is the minimum value of the
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data, and the second is the maximum. This is used for images with
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IMAGE_SUBCLASS="IMAGE_GRAYSCALE", "IMAGE_BITMAP" or "IMAGE_INDEXED".</dd>
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</dl>
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<dt>
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Attribute name="<b>IMAGE_BACKGROUNDINDEX</b>"</dt>
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<dl>
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<dd>
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If set, this attribute indicates the index value that should be interpreted
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as the "background color". This attribute is HDF5 type H5T_NATIVE_UINT.</dd>
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</dl>
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<dt>
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Attribute name="<b>IMAGE_TRANSPARENCY</b>"</dt>
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<dl>
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<dd>
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If set, this attribute indicates the index value that should be interpreted
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as the "transparent color". This attribute is HDF5 type H5T_NATIVE_UINT.
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This attribute may not be used for IMAGE_SUBCLASS="IMAGE_TRUE_COLOR".</dd>
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</dl>
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<dt>
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Attribute name="<b>IMAGE_ASPECTRATIO</b>"</dt>
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<dl>
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<dd>
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If set, this attribute indicates the aspect ratio.</dd>
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</dl>
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<dt>
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Attribute name="<b>IMAGE_COLORMODEL</b>"</dt>
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<dl>
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<dd>
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If set, this attribute indicates the color model of Palette that should
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be used with the Image. This attribute is of type H5T_C_S1, with
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size 3, 4, or 5. The value is one of the color models described in
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the Palette specification in <a href="#sect2.2">section 2.2 below</a>.
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This attribute may be used only for IMAGE_SUBCLASS="IMAGE_TRUECOLOR" or
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"IMAGE_INDEXED".</dd>
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</dl>
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<dt>
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Attribute name="<b>IMAGE_GAMMACORRECTION</b>"</dt>
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<dl>
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<dd>
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If set, this attribute gives the Gamma correction. The attribute
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is type H5T_NATIVE_FLOAT. This attribute may be used only for IMAGE_SUBCLASS="IMAGE_TRUECOLOR"
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or "IMAGE_INDEXED".</dd>
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</dl>
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Attribute name="<b>IMAGE_VERSION</b>" (Required)
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<dl>
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<dd>
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This attribute is of type H5T_C_S1, with size corresponding to the length
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of the version string. This attribute identifies the version number
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of this specification to which it conforms. The current version number
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is "1.2".</dd>
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<br>
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<p>
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<br>
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<br>
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<center><table BORDER=2 BGCOLOR="#FFFFFF" >
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<caption><b>Table 1. Attributes of an Image Dataset</b></caption>
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<tr>
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<td><b>Attribute Name</b></td>
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<td><b>(R = Required</b>
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<br><b>O= Optional)</b></td>
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<td><b>Type</b></td>
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<td><b>String Size</b></td>
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<td><b>Value</b></td>
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</tr>
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<tr>
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<td>CLASS</td>
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<td>R</td>
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<td>String</td>
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<td>5</td>
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<td>"IMAGE"</td>
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</tr>
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<tr>
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<td>PALETTE</td>
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<td>O</td>
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<td>Array Object References</td>
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<td></td>
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<td><references to Palette datasets><sup>1</sup></td>
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</tr>
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<tr>
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<td>IMAGE_SUBCLASS</td>
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<td>O<sup>2</sup></td>
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<td>String</td>
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<td>15,
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<br>12,
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<br>15,
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<br>13</td>
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<td>
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<dt>
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"IMAGE_GRAYSCALE",</dt>
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<dt>
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"IMAGE_BITMAP",</dt>
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<dt>
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"IMAGE_TRUECOLOR",</dt>
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<dt>
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"IMAGE_INDEXED"</dt>
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</td>
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</tr>
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<tr>
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<td>INTERLACE_MODE</td>
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<td>O<sup>3,6</sup></td>
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<td>String</td>
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<td>15</td>
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<td>The layout of components if more than one component per pixel.</td>
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</tr>
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<tr>
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<td>DISPLAY_ORIGIN</td>
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<td>O</td>
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<td>String</td>
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<td>2</td>
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<td>If set, indicates the intended location of the pixel (0,0).</td>
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</tr>
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<tr>
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<td>IMAGE_WHITE_IS_ZERO</td>
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<td>O<sup>3,4</sup></td>
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<td>Unsigned Integer</td>
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<td></td>
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<td>0 = false, 1 = true</td>
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</tr>
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<tr>
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<td>IMAGE_MINMAXRANGE</td>
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<td>O<sup>3,5</sup></td>
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<td>Array [2] <same datatype as data values></td>
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<td></td>
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<td>The (<minimum>, <maximum>) value of the data.</td>
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</tr>
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<tr>
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<td>IMAGE_BACKGROUNDINDEX</td>
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<td>O<sup>3</sup></td>
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<td>Unsigned Integer</td>
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<td></td>
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<td>The index of the background color.</td>
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</tr>
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<tr>
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<td>IMAGE_TRANSPARENCY</td>
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<td>O<sup>3,5</sup></td>
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<td>Unsigned Integer</td>
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<td></td>
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<td>The index of the transparent color.</td>
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</tr>
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<tr>
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<td>IMAGE_ASPECTRATIO</td>
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<td>O<sup>3,4</sup></td>
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<td>Unsigned Integer</td>
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<td></td>
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<td>The aspect ratio.</td>
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</tr>
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<tr>
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<td>IMAGE_COLORMODEL</td>
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<td>O<sup>3,6</sup></td>
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<td>String</td>
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<td>3, 4, or 5</td>
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<td>The color model, as defined below in the Palette specification for
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attribute <b>PAL_COLORMODEL</b>.</td>
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</tr>
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<tr>
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<td>IMAGE_GAMMACORRECTION</td>
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<td>O<sup>3,6</sup></td>
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<td>Float</td>
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<td></td>
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<td>The gamma correction.</td>
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</tr>
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<tr>
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<td>IMAGE_VERSION</td>
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<td>R</td>
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<td>String</td>
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|
|
|
<td>3</td>
|
|
|
|
<td>"1.2"</td>
|
|
</tr>
|
|
</table></center>
|
|
|
|
<dl><font size=-1>1. The first element of the array is the default
|
|
Palette.</font>
|
|
<br><font size=-1>2. This attribute is <b>required</b> for images
|
|
that use one of the standard color map types listed.</font>
|
|
<br><font size=-1>3. This attribute is <b>required</b> if set for the source
|
|
image, in the case that the image is translated from another file into
|
|
HDF5.</font>
|
|
<br><font size=-1>4. This applies to: IMAGE_SUBCLASS="IMAGE_GRAYSCALE"
|
|
or "IMAGE_BITMAP".</font>
|
|
<br><font size=-1>5. This applies to: IMAGE_SUBCLASS="IMAGE_GRAYSCALE",
|
|
"IMAGE_BITMAP", or "IMAGE_INDEXED".</font>
|
|
<br><font size=-1>6. This applies to: IMAGE_SUBCLASS="IMAGE_TRUECOLOR",
|
|
or "IMAGE_INDEXED".</font></dl>
|
|
</dl>
|
|
Table 2 summarizes the standard attributes for an Image datasets using
|
|
the common sub-classes. R means that the attribute listed on the leftmost
|
|
column is Required for the image subclass on the first row, O means that
|
|
the attribute is Optional for that subclass and N that the attribute cannot
|
|
be applied to that subclass. The two first rows show the only required
|
|
attributes
|
|
for all subclasses.
|
|
<br>
|
|
<table BORDER WIDTH="100%" >
|
|
<caption><b>Table 2a. Applicability of Attributes to IMAGE sub-classes</b></caption>
|
|
|
|
<tr>
|
|
<td WIDTH="20%"><b>IMAGE_SUBCLASS</b><sup>1</sup></td>
|
|
|
|
<td WIDTH="20%"><b>IMAGE_GRAYSCALE</b></td>
|
|
|
|
<td WIDTH="20%"><b>IMAGE_BITMAP</b></td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td WIDTH="20%">CLASS</td>
|
|
|
|
<td WIDTH="20%">R</td>
|
|
|
|
<td WIDTH="20%">R</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td WIDTH="20%">IMAGE_VERSION</td>
|
|
|
|
<td WIDTH="20%">R</td>
|
|
|
|
<td WIDTH="20%">R</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td>INTERLACE_MODE</td>
|
|
|
|
<td>N</td>
|
|
|
|
<td>N</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td WIDTH="20%">IMAGE_WHITE_IS_ZERO</td>
|
|
|
|
<td WIDTH="20%">R</td>
|
|
|
|
<td WIDTH="20%">R</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td WIDTH="20%">IMAGE_MINMAXRANGE</td>
|
|
|
|
<td WIDTH="20%">O</td>
|
|
|
|
<td WIDTH="20%">O</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td WIDTH="20%">IMAGE_BACKGROUNDINDEX</td>
|
|
|
|
<td WIDTH="20%">O</td>
|
|
|
|
<td WIDTH="20%">O</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td WIDTH="20%">IMAGE_TRANSPARENCY</td>
|
|
|
|
<td WIDTH="20%">O</td>
|
|
|
|
<td WIDTH="20%">O</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td WIDTH="20%">IMAGE_ASPECTRATIO</td>
|
|
|
|
<td WIDTH="20%">O</td>
|
|
|
|
<td WIDTH="20%">O</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td WIDTH="20%">IMAGE_COLORMODEL</td>
|
|
|
|
<td WIDTH="20%">N</td>
|
|
|
|
<td WIDTH="20%">N</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td WIDTH="20%">IMAGE_GAMMACORRECTION</td>
|
|
|
|
<td WIDTH="20%">N</td>
|
|
|
|
<td WIDTH="20%">N</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td WIDTH="20%">PALETTE</td>
|
|
|
|
<td WIDTH="20%">O</td>
|
|
|
|
<td WIDTH="20%">O</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td>DISPLAY_ORIGIN</td>
|
|
|
|
<td>O</td>
|
|
|
|
<td>O</td>
|
|
</tr>
|
|
</table>
|
|
|
|
<blockquote> </blockquote>
|
|
|
|
<table BORDER WIDTH="100%" >
|
|
<caption><b>Table 2b. Applicability of Attributes to IMAGE sub-classes</b></caption>
|
|
|
|
<tr>
|
|
<td WIDTH="20%"><b>IMAGE_SUBCLASS</b></td>
|
|
|
|
<td WIDTH="20%"><b>IMAGE_TRUECOLOR</b></td>
|
|
|
|
<td><b>IMAGE_INDEXED</b></td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td WIDTH="20%">CLASS</td>
|
|
|
|
<td WIDTH="20%">R</td>
|
|
|
|
<td>R</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td WIDTH="20%">IMAGE_VERSION</td>
|
|
|
|
<td WIDTH="20%">R</td>
|
|
|
|
<td>R</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td>INTERLACE_MODE</td>
|
|
|
|
<td>R</td>
|
|
|
|
<td>N</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td WIDTH="20%">IMAGE_WHITE_IS_ZERO</td>
|
|
|
|
<td WIDTH="20%">N</td>
|
|
|
|
<td>N</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td WIDTH="20%">IMAGE_MINMAXRANGE</td>
|
|
|
|
<td WIDTH="20%">N</td>
|
|
|
|
<td>O</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td WIDTH="20%">IMAGE_BACKGROUNDINDEX</td>
|
|
|
|
<td WIDTH="20%">N</td>
|
|
|
|
<td>O</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td WIDTH="20%">IMAGE_TRANSPARENCY</td>
|
|
|
|
<td WIDTH="20%">N</td>
|
|
|
|
<td>O</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td WIDTH="20%">IMAGE_ASPECTRATIO</td>
|
|
|
|
<td WIDTH="20%">O</td>
|
|
|
|
<td>O</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td WIDTH="20%">IMAGE_COLORMODEL</td>
|
|
|
|
<td WIDTH="20%">O</td>
|
|
|
|
<td>O</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td WIDTH="20%">IMAGE_GAMMACORRECTION</td>
|
|
|
|
<td WIDTH="20%">O</td>
|
|
|
|
<td>O</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td WIDTH="20%">PALETTE</td>
|
|
|
|
<td WIDTH="20%">O</td>
|
|
|
|
<td>O</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td>DISPLAY_ORIGIN</td>
|
|
|
|
<td>O</td>
|
|
|
|
<td>O</td>
|
|
</tr>
|
|
</table>
|
|
|
|
<h3>
|
|
<a NAME="Section1.3"></a>1.3 Storage Layout and Properties for Images</h3>
|
|
In the case of an image with more than one component per pixel (e.g., Red,
|
|
Green, and Blue), the data may be arranged in one of two ways. Following
|
|
HDF4 terminology, the data may be interlaced by pixel or by plane, which
|
|
should be indicated by the INTERLACE_MODE attribute. In both
|
|
cases, the dataset will have a dataspace with three dimensions, height,
|
|
width, and components. The interlace modes specify different orders
|
|
for the dimensions.
|
|
<br>
|
|
<table BORDER COLS=2 WIDTH="100%" >
|
|
<caption><b>Table 3. Storage of multiple component image data.</b></caption>
|
|
|
|
<tr>
|
|
<td><b>Interlace Mode</b></td>
|
|
|
|
<td><b>Dimensions in the Dataspace</b></td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td>INTERLACE_PIXEL</td>
|
|
|
|
<td>[height][width][pixel components]</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td>INTERLACE_PLANE</td>
|
|
|
|
<td>[pixel components][height][width]</td>
|
|
</tr>
|
|
</table>
|
|
|
|
<p>For example, consider a 5 (rows) by 10 (column) image, with Red, Green,
|
|
and Blue components. Each component is an unsigned byte. In HDF5,
|
|
the datatype would be declared as an unsigned 8 bit integer. For
|
|
pixel interlace, the dataspace would be a three dimensional array, with
|
|
dimensions: [10][5][3]. For plane interleave, the dataspace would
|
|
be three dimensions: [3][10][5].
|
|
<p>In the case of images with only one component, the dataspace may be
|
|
either a two dimensional array, or a three dimensional array with the third
|
|
dimension of size 1. For example, a 5 by 10 image with 8 bit color
|
|
indexes would be an HDF5 dataset with type unsigned 8 bit integer.
|
|
The dataspace could be either a two dimensional array, with dimensions
|
|
[10][5], or three dimensions, with dimensions either [10][5][1] or [1][10][5].
|
|
<p>Image datasets may be stored with any chunking or compression properties
|
|
supported by HDF5.
|
|
<p><b>A note concerning compatibility with HDF5 GR interface: </b>An Image
|
|
dataset is stored as an HDF5 dataset. It is important to note that
|
|
the order of the dimensions is the same as for any other HDF5 dataset.
|
|
For a two dimensional image that is to be stored as a series of horizontal
|
|
scan lines, with the scan lines contiguous (i.e., the fastest changing
|
|
dimension is 'width'), the image will have a dataspace with <i>dim[0] =
|
|
height</i> and <i>dim[1]</i> = <i>width</i>. This is completely consistent
|
|
with all other HDF5 datasets.
|
|
<p>Users familiar with HDF4 should be cautioned that <i>this is not the
|
|
same as HDF4</i>, and specifically is not consistent with what the HDF4
|
|
GR interface does.
|
|
<br>
|
|
<h2>
|
|
<a NAME="sect2"></a>2. HDF5 Palette Specification</h2>
|
|
|
|
<h3>
|
|
2.1 Overview</h3>
|
|
A palette is the means by which color is applied to an image and is also
|
|
referred to as a color lookup table. It is a table in which every row contains
|
|
the numerical representation of a particular color. In the example of an
|
|
8 bit standard RGB color model palette, this numerical representation of
|
|
a color is presented as a triplet specifying the intensity of red, green,
|
|
and blue components that make up each color.
|
|
<center>
|
|
<p><img SRC="Palettes.fm.anc.gif" ></center>
|
|
|
|
<p>In this example, the color component numeric type is an 8 bit unsigned
|
|
integer. While this is most common and recommended for general use, other
|
|
component color numeric datatypes, such as a 16 bit unsigned integer ,
|
|
may be used. This type is specified as the type attribute of the palette
|
|
dataset. (see H5Tget_type(), H5Tset_type())
|
|
<p>The minimum and maximum values of the component color numeric are specified
|
|
as attribute of the palette dataset. See below (attribute PAL_MINMAXNUMERIC).
|
|
If these attributes do not exist, it is assumed that the range of values
|
|
will fill the space of the color numeric type. i.e. with an 8 bit unsigned
|
|
integer, the valid range would be 0 to 255 for each color component.
|
|
<p>The HDF5 palette specification additionally allows for color models
|
|
beyond RGB. YUV, HSV, CMY, CMYK, YCbCr color models are supported, and
|
|
may be specified as a color model attribute of the palette dataset. <i>(see
|
|
"Palette Attributes" for details)</i>.
|
|
<p>In HDF 4 and earlier, palettes were limited to 256 colors. The HDF5
|
|
palette specification allows for palettes of varying length. The length
|
|
is specified as the number of rows of the palette dataset.
|
|
<br>
|
|
<br>
|
|
<table BORDER COLS=1 WIDTH="100%" BGCOLOR="#666666" >
|
|
<tr>
|
|
<td><font color="#FFFFFF">Important Note: The specification of the Indexed
|
|
Palette will change substantially in the next version. The Palette
|
|
described here is <i>denigrated</i> and is not supported.</font></td>
|
|
</tr>
|
|
</table>
|
|
|
|
<br>
|
|
<table BORDER COLS=1 WIDTH="100%" BGCOLOR="#CCCCCC" >
|
|
<tr>
|
|
<td><i>Denigrated</i>
|
|
<p>In a standard palette, the color entries are indexed directly. HDF5
|
|
supports the notion of a range index table. Such a table defines an ascending
|
|
ordered list of ranges that map dataset values to the palette. If a range
|
|
index table exists for the palette, the PAL_TYPE attribute will be set
|
|
to "RANGEINDEX", and the PAL_RANGEINDEX attribute will contain an object
|
|
reference to a range index table array. If not, the PAL_TYPE attribute
|
|
either does not exist, or will be set to "STANDARD".
|
|
<p>The range index table array consists of a one dimensional array with
|
|
the same length as the palette dataset - 1. Ideally, the range index would
|
|
be of the same type as the dataset it refers to, however this is not a
|
|
requirement.
|
|
<p><b>Example 2: A range index array of type floating point</b>
|
|
<center>
|
|
<p><img SRC="PaletteExample1.gif" ></center>
|
|
|
|
<p>The range index array attribute defines the "<i>to</i>" of the range.
|
|
Notice that the range index array attribute is one less entry in size than
|
|
the palette. The first entry of 0.1259, specifies that all values below
|
|
and up to 0.1259 inclusive, will map to the first palette entry. The second
|
|
entry signifies that all values greater than 0.1259 up to 0.3278 inclusive,
|
|
will map to the second palette entry, etc. All value greater than the last
|
|
range index array attribute (100000) map to the last entry in the palette.</td>
|
|
</tr>
|
|
</table>
|
|
|
|
<h3>
|
|
<a NAME="sect2.2"></a>2.2. Palette Attributes</h3>
|
|
A palette exists in an HDF file as an independent data set with accompanying
|
|
attributes. The Palette attributes are scalars except where noted
|
|
otherwise. String values should have size the length of the string
|
|
value plus one. "Required" attributes must be used. "Optional"
|
|
attributes must be used when required.
|
|
<p>These attributes are defined as follows:
|
|
<dl>
|
|
<dt>
|
|
Attribute name="<b>CLASS</b>" (Required)</dt>
|
|
|
|
<dd>
|
|
This attribute is of type H5T_C_S1, with size 7.</dd>
|
|
|
|
<dd>
|
|
For all palettes, the value of this attribute is "PALETTE". This attribute
|
|
identifies this palette data set as a palette that conforms to the specifications
|
|
on this page.</dd>
|
|
|
|
<dt>
|
|
Attribute name="<b>PAL_COLORMODEL</b>" (Required)</dt>
|
|
|
|
<dd>
|
|
This attribute is of type H5T_C_S1, with size 3, 4, or 5.</dd>
|
|
|
|
<dd>
|
|
Possible values for this are "RGB", "YUV", "CMY", "CMYK", "YCbCr", "HSV".</dd>
|
|
|
|
<dd>
|
|
This defines the color model that the entries in the palette data set represent.</dd>
|
|
|
|
<dl>
|
|
<dt>
|
|
"RGB"</dt>
|
|
|
|
<dd>
|
|
Each color index contains a triplet where the the first value defines the
|
|
red component, second defines the green component, and the third the blue
|
|
component.</dd>
|
|
|
|
<dt>
|
|
"CMY"</dt>
|
|
|
|
<dd>
|
|
Each color index contains a triplet where the the first value defines the
|
|
cyan component, second defines the magenta component, and the third the
|
|
yellow component.</dd>
|
|
|
|
<dt>
|
|
"CMYK"</dt>
|
|
|
|
<dd>
|
|
Each color index contains a quadruplet where the the first value defines
|
|
the cyan component, second defines the magenta component, the third the
|
|
yellow component, and the forth the black component.</dd>
|
|
|
|
<dt>
|
|
"YCbCr"</dt>
|
|
|
|
<dd>
|
|
Class Y encoding model. Each color index contains a triplet where the the
|
|
first value defines the luminance, second defines the Cb Chromonance, and
|
|
the third the Cr Chromonance.</dd>
|
|
|
|
<dt>
|
|
"YUV"</dt>
|
|
|
|
<dd>
|
|
Composite encoding color model. Each color index contains a triplet where
|
|
the the first value defines the luminance component, second defines the
|
|
chromonance component, and the third the value component.</dd>
|
|
|
|
<dt>
|
|
"HSV"</dt>
|
|
|
|
<dd>
|
|
Each color index contains a triplet where the the first value defines the
|
|
hue component, second defines the saturation component, and the third the
|
|
value component. The hue component defines the hue spectrum with a low
|
|
value representing magenta/red progressing to a high value which would
|
|
represent blue/magenta, passing through yellow, green, cyan. A low value
|
|
for the saturation component means less color saturation than a high value.
|
|
A low value for <i>value</i> will be darker than a high value.</dd>
|
|
|
|
<dd>
|
|
</dd>
|
|
</dl>
|
|
|
|
<dt>
|
|
Attribute name="<b>PAL_TYPE</b>" (Required)</dt>
|
|
|
|
<dd>
|
|
This attribute is of type H5T_C_S1, with size 9 or 10.</dd>
|
|
|
|
<dd>
|
|
The current supported values for this attribute are : "STANDARD8" or "RANGEINDEX"</dd>
|
|
|
|
<dd>
|
|
A PAL_TYPE of "STANDARD8" defines a palette dataset such that the first
|
|
entry defines index 0, the second entry defines index 1, etc. up until
|
|
the length of the palette - 1. This assumes an image dataset with direct
|
|
indexes into the palette.</dd>
|
|
</dl>
|
|
|
|
<dl>
|
|
<table BORDER COLS=1 WIDTH="100%" BGCOLOR="#CCCCCC" >
|
|
<tr>
|
|
<td><i>Denigrated</i>
|
|
<p>If the PAL_TYPE is set to "RANGEINDEX", there will be an additional
|
|
attribute with a name of "<b>PAL_RANGEINDEX</b>", (See example 2
|
|
for more details)</td>
|
|
</tr>
|
|
</table>
|
|
|
|
<table BORDER COLS=1 WIDTH="100%" BGCOLOR="#CCCCCC" >
|
|
<tr>
|
|
<td>
|
|
<dt>
|
|
Attribute name="<b>PAL_RANGEINDEX</b>" <i>(Denigrated)</i></dt>
|
|
|
|
<dl>
|
|
<dd>
|
|
The <b>PAL_RANGEINDEX</b> attribute contains an HDF object reference (HDF5
|
|
datatype H5T_STD_REF_OBJ) pointer which specifies a range index array in
|
|
the file to be used for color lookups for the palette. (Only for
|
|
PAL_TYPE="RANGEINDEX")</dd>
|
|
</dl>
|
|
</td>
|
|
</tr>
|
|
</table>
|
|
|
|
<dt>
|
|
Attribute name="<b>PAL_MINMAXNUMERIC</b>"</dt>
|
|
|
|
<dl>
|
|
<dt>
|
|
If present, this attribute is an array of two numbers, of the same HDF5
|
|
datatype as the palette elements or color numerics.</dt>
|
|
|
|
<br>They specify the minimum and maximum values of the color numeric components.
|
|
For example, if the palette was an RGB of type Float, the color numeric
|
|
range for Red, Green, and Blue could be set to be between 0.0 and 1.0.
|
|
The intensity of the color guns would then be scaled accordingly to be
|
|
between this minimum and maximum attribute.</dl>
|
|
Attribute name="<b>PAL_VERSION</b>" (Required)
|
|
<dl>This attribute is of type H5T_C_S1, with size corresponding to the
|
|
length of the version string. This attribute identifies the version
|
|
number of this specification to which it conforms. The current version
|
|
is "1.2".</dl>
|
|
|
|
<center><table BORDER=2 BGCOLOR="#FFFFFF" >
|
|
<caption><b>Table 4. Attributes of a Palette Dataset</b></caption>
|
|
|
|
<tr>
|
|
<td><b>Attribute Name</b></td>
|
|
|
|
<td><b>(R = Required,</b>
|
|
<br><b>O = Optional)</b></td>
|
|
|
|
<td><b>Type</b></td>
|
|
|
|
<td><b>String Size</b></td>
|
|
|
|
<td><b>Value</b></td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td>CLASS</td>
|
|
|
|
<td>R</td>
|
|
|
|
<td>String</td>
|
|
|
|
<td>
|
|
<center>7</center>
|
|
</td>
|
|
|
|
<td>"PALETTE"</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td>PAL_COLORMODEL</td>
|
|
|
|
<td>R</td>
|
|
|
|
<td>String</td>
|
|
|
|
<td>
|
|
<center>3, 4, or 5</center>
|
|
</td>
|
|
|
|
<td>Color Model: "RGB", YUV", "CMY", "CMYK", "YCbCr", or "HSV"</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td>PAL_TYPE</td>
|
|
|
|
<td>R</td>
|
|
|
|
<td>String</td>
|
|
|
|
<td>
|
|
<center>9</center>
|
|
|
|
<p><br>
|
|
<table BORDER COLS=1 WIDTH="100%" BGCOLOR="#CCCCCC" >
|
|
<tr>
|
|
<td>or 10</td>
|
|
</tr>
|
|
</table>
|
|
</td>
|
|
|
|
<td>"STANDARD8"
|
|
<table BORDER COLS=1 WIDTH="100%" BGCOLOR="#CCCCCC" >
|
|
<tr>
|
|
<td>or "RANGEINDEX" <i>(Denigrated)</i></td>
|
|
</tr>
|
|
</table>
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td>
|
|
<table BORDER COLS=1 WIDTH="100%" BGCOLOR="#CCCCCC" >
|
|
<tr>
|
|
<td><i>Denigrated</i>
|
|
<br>RANGE_INDEX</td>
|
|
</tr>
|
|
</table>
|
|
</td>
|
|
|
|
<td></td>
|
|
|
|
<td>
|
|
<table BORDER COLS=1 WIDTH="100%" BGCOLOR="#CCCCCC" >
|
|
<tr>
|
|
<td>Object Reference </td>
|
|
</tr>
|
|
</table>
|
|
</td>
|
|
|
|
<td></td>
|
|
|
|
<td>
|
|
<table BORDER COLS=1 WIDTH="100%" BGCOLOR="#CCCCCC" >
|
|
<tr>
|
|
<td><Object Reference to Dataset of range index values></td>
|
|
</tr>
|
|
</table>
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td>PAL_MINMAXNUMERIC</td>
|
|
|
|
<td>O</td>
|
|
|
|
<td>Array[2] of <same datatype as palette></td>
|
|
|
|
<td></td>
|
|
|
|
<td>The first value is the <Minimum value for color values>, the second
|
|
value is <Maximum value for color values><sup>2</sup></td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td>PAL_VERSION</td>
|
|
|
|
<td>R</td>
|
|
|
|
<td>String</td>
|
|
|
|
<td>4</td>
|
|
|
|
<td>"1.2"</td>
|
|
</tr>
|
|
</table></center>
|
|
|
|
<dl>
|
|
<table BORDER COLS=1 WIDTH="100%" BGCOLOR="#CCCCCC" >
|
|
<tr>
|
|
<td><font size=-1>1. The RANGE_INDEX attribute is required if the
|
|
PAL_TYPE is "RANGEINDEX". Otherwise, the RANGE_INDEX attribute should
|
|
be omitted. (Range index is denigrated.)</font></td>
|
|
</tr>
|
|
</table>
|
|
<font size=-1>2. The minimum and maximum are optional. If not
|
|
set, the range is assumed to the maximum range of the number type.
|
|
If one of these attributes is set, then both should be set. The value
|
|
of the minimum must be less than or equal to the value of the maximum.</font></dl>
|
|
</dl>
|
|
Table 5 summarized the uses of the standard attributes for a palette dataset.
|
|
R means that the attribute listed on the leftmost column is Required for
|
|
the palette type on the first row, O means that the attribute is Optional
|
|
for that type and N that the attribute cannot be applied to that type.
|
|
The four first rows show the attributes that are always required
|
|
for the two palette types.
|
|
<br>
|
|
<br>
|
|
<table BORDER WIDTH="100%" >
|
|
<caption><b>Table 5. Applicability of Attributes</b></caption>
|
|
|
|
<tr>
|
|
<td WIDTH="33%"><b>PAL_TYPE</b></td>
|
|
|
|
<td WIDTH="33%"><b>STANDARD8</b></td>
|
|
|
|
<td WIDTH="34%"><b>RANGEINDEX</b></td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td WIDTH="33%">CLASS</td>
|
|
|
|
<td WIDTH="33%">R</td>
|
|
|
|
<td WIDTH="34%">R</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td WIDTH="33%">PAL_VERSION</td>
|
|
|
|
<td WIDTH="33%">R</td>
|
|
|
|
<td WIDTH="34%">R</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td WIDTH="33%">PAL_COLORMODEL</td>
|
|
|
|
<td WIDTH="33%">R</td>
|
|
|
|
<td WIDTH="34%">R</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td WIDTH="33%">RANGE_INDEX</td>
|
|
|
|
<td WIDTH="33%">N</td>
|
|
|
|
<td WIDTH="34%">R</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td WIDTH="33%">PAL_MINMAXNUMERIC</td>
|
|
|
|
<td WIDTH="33%">O</td>
|
|
|
|
<td WIDTH="34%">O</td>
|
|
</tr>
|
|
</table>
|
|
|
|
<h3>
|
|
2.3. Storage Layout for Palettes</h3>
|
|
The values of the Palette are stored as a dataset. The datatype can
|
|
be any HDF 5 atomic numeric type. The dataset will have dimensions
|
|
(<tt>nentries</tt> by <tt>ncomponents</tt>), where '<tt>nentries</tt>'
|
|
is the number of colors (usually 256) and '<tt>ncomponents'</tt> is the
|
|
number of values per color (3 for <b>RGB</b>, 4 for <b>CMYK</b>, etc.)
|
|
<br>
|
|
<h2>
|
|
<a NAME="Sect3"></a>3. Consistency and Correlation of Image and Palette
|
|
Attributes</h2>
|
|
The objects in this specification are an extension to the base HDF5 specification
|
|
and library. They are accessible with the standard HDF5 library,
|
|
but the semantics of the objects are not enforced by the base library.
|
|
For example, it is perfectly possible to add an attribute called <b>IMAGE</b>
|
|
to <i>any</i> dataset, or to include an object reference to <i>any</i>
|
|
HDF5 dataset in a <b>PALETTE</b> attribute. This would be a valid
|
|
HDF5 file, but not conformant to this specification. The rules defined
|
|
in this specification must be implemented with appropriate software, and
|
|
applications must use conforming software to assure correctness.
|
|
<p>The Image and Palette specifications include several redundant standard
|
|
attributes, such as the <b>IMAGE_COLORMODEL</b> and the <b>PAL_COLORMODEL</b>.
|
|
These attributes are informative not normative, in that it is acceptable
|
|
to attach a Palette to an Image dataset even if their attributes do not
|
|
match. Software is not required to enforce consistency, and files
|
|
may contain mismatched associations of Images and Palettes. In all
|
|
cases, it is up to applications to determine what kinds of images and color
|
|
models can be supported.
|
|
<p>For example, an Image that was created from a file with an "RGB" may
|
|
have a "YUV" Palette in its <b>PALETTE</b> attribute array. This
|
|
would be a legal HDF5 file and also conforms to this specification, although
|
|
it may or may not be correct for a given application.</p>
|
|
|
|
</body>
|
|
</html>
|