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diff --git a/doxygen/examples/ImageSpec.html b/doxygen/examples/ImageSpec.html new file mode 100644 index 0000000..1b700ff --- /dev/null +++ b/doxygen/examples/ImageSpec.html @@ -0,0 +1,1203 @@ +<!doctype html public "-//w3c//dtd html 4.0 transitional//en"> +<html> +<head> + <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> + <meta name="GENERATOR" content="Mozilla/4.72 [en] (WinNT; U) [Netscape]"> + <title>Image Specification</title> + +The HDF5 specification defines the standard objects and storage for the +standard HDF5 objects. (For information about the HDF5 library, model and +specification, see the HDF documentation.) This document is an additional +specification do define a standard profile for how to store image data +in HDF5. Image data in HDF5 is stored as HDF5 datasets with standard attributes +to define the properties of the image. +<p>This specification is primarily concerned with two dimensional raster +data similar to HDF4 Raster Images. Specifications for storing other +types of imagery will be covered in other documents. +<p>This specification defines: +<ul> +<li> +Standard storage and attributes for an Image dataset (<a href="#Sect1">Section +1</a>)</li> + +<li> +Standard storage and attributes for Palettes (<a href="#sect2">Section +2</a>)</li> + +<li> +Standard for associating Palettes with Images. (<a href="#Sect3">Section +3</a>)</li> +</ul> + +<h2> +<a NAME="Sect1"></a>1. HDF5 Image Specification</h2> + +<h3> +1.1 Overview</h3> +Image data is stored as an HDF5 dataset with values of HDF5 class Integer +or Float. A common example would be a two dimensional dataset, with +elements of class Integer, e.g., a two dimensional array of unsigned 8 +bit integers. However, this specification does not limit the dimensions +or number type that may be used for an Image. +<p>The dataset for an image is distinguished from other datasets by giving +it an attribute "CLASS=IMAGE". In addition, the Image dataset may +have an optional attribute "PALETTE" that is an array of object references +for zero or more palettes. The Image dataset may have additional attributes +to describe the image data, as defined in <a href="#Sect1.2">Section 1.2</a>. +<p>A Palette is an HDF5 dataset which contains color map information. +A Pallet dataset has an attribute "CLASS=PALETTE" and other attributes +indicating the type and size of the palette, as defined in <a href="#sect2">Section +2.1</a>. A Palette is an independent object, which can be shared +among several Image datasets. +<h3> +<a NAME="Sect1.2"></a>1.2 Image Attributes</h3> +The attributes for the Image are scalars unless otherwise noted. +The length of String valued attributes should be at least the number of +characters. Optionally, String valued attributes may be stored in a String +longer than the minimum, in which case it must be zero terminated or null +padded. "Required" attributes must always be used. "Optional" attributes +must be used when required. +<br> +<h4> +Attributes</h4> + +<dl> +<dt> +Attribute name="<b>CLASS</b>" (Required)</dt> + +<dd> +This attribute is type H5T_C_S1, with size 5.</dd> + +<dd> +For all Images, the value of this attribute is "IMAGE".</dd> + +<dd> +</dd> + +<dd> +This attribute identifies this data set as intended to be interpreted as +an image that conforms to the specifications on this page.</dd> +</dl> + +<dt> +Attribute name="<b>PALETTE</b>"</dt> + +<dl> +<dd> +A Image dataset within an HDF5 file may optionally specify an array of +palettes to be viewed with. The dataset will have an attribute field called +"<b>PALETTE</b>" which contains a one-dimensional array of object reference +pointers (HDF5 datatype H5T_STD_REF_OBJ) which refer to palettes in the +file. The palette datasets must conform to the Palette specification in +<a href="#sect2">section +2 below</a>. The first palette in this array will be the default palette +that the data may be viewed with.</dd> +</dl> + +<dl> +<dt> +</dt> + +<dt> +Attribute name="<b>IMAGE_SUBCLASS</b>"</dt> + +<dd> +If present, the value of this attribute indicates the type of Palette that +should be used with the Image. This attribute is a scalar of type +H5T_C_S1, with size according to the string plus one. The values +are:</dd> + +<dl> +<dt> +"IMAGE_GRAYSCALE" (length 15)</dt> + +<dd> +A grayscale image</dd> + +<dt> +"IMAGE_BITMAP" (length 12)</dt> + +<dd> +A bit map image</dd> + +<dt> +"IMAGE_TRUECOLOR" (length 15)</dt> + +<dd> +A truecolor image</dd> + +<dt> +"IMAGE_INDEXED" (length 13)</dt> + +<dd> +An indexed image</dd> + +<dd> +</dd> +</dl> + +<dt> +Attribute name="<b>INTERLACE_MODE</b>"</dt> + +<dd> +For images with more than one component for each pixel, this optional attribute +specifies the layout of the data. The values are type H5T_C_S1 of length +15. See <a href="#Section1.3">section 1.3</a> for information about the +storage layout for data.</dd> + +<dd> +"INTERLACE_PIXEL" (default): the component value for a pixel are contiguous.</dd> + +<dd> +"INTERLACE_PLANE": each component is stored as a plane.</dd> + +<dt> +</dt> + +<dt> +Attribute name="<b>DISPLAY_ORIGIN</b>"</dt> + +<dd> +This optional attribute indicates the intended orientation of the data +on a two-dimensional raster display. The value indicates which corner +the pixel at (0, 0) should be viewed. The values are type H5T_C_S1 +of length 2. If DISPLAY_ORIGIN is not set, the orientation is undefined.</dd> + +<dd> +"UL": (0,0) is at the upper left.</dd> + +<dd> +"LL": (0,0) is at the lower left.</dd> + +<dd> +"UR": (0,0) is at the upper right.</dd> + +<dd> +"LR": (0,0) is at the lower right.</dd> +</dl> + +<dt> +Attribute name="<b>IMAGE_WHITE_IS_ZERO</b>"</dt> + +<dl> +<dd> +This attribute is of type H5T_NATIVE_UCHAR. 0 = false, 1 = true . +This is used for images with IMAGE_SUBCLASS="IMAGE_GRAYSCALE" or "IMAGE_BITMAP".</dd> +</dl> + +<dl> +<dt> +Attribute name="<b>IMAGE_MINMAXRANGE</b>"</dt> + +<dd> +If present, this attribute is an array of two numbers, of the same HDF5 +datatype as the data. The first element is the minimum value of the +data, and the second is the maximum. This is used for images with +IMAGE_SUBCLASS="IMAGE_GRAYSCALE", "IMAGE_BITMAP" or "IMAGE_INDEXED".</dd> +</dl> + +<dt> +Attribute name="<b>IMAGE_BACKGROUNDINDEX</b>"</dt> + +<dl> +<dd> +If set, this attribute indicates the index value that should be interpreted +as the "background color". This attribute is HDF5 type H5T_NATIVE_UINT.</dd> +</dl> + +<dt> +Attribute name="<b>IMAGE_TRANSPARENCY</b>"</dt> + +<dl> +<dd> +If set, this attribute indicates the index value that should be interpreted +as the "transparent color". This attribute is HDF5 type H5T_NATIVE_UINT. +This attribute may not be used for IMAGE_SUBCLASS="IMAGE_TRUE_COLOR".</dd> +</dl> + +<dt> +Attribute name="<b>IMAGE_ASPECTRATIO</b>"</dt> + +<dl> +<dd> +If set, this attribute indicates the aspect ratio.</dd> +</dl> + +<dt> +Attribute name="<b>IMAGE_COLORMODEL</b>"</dt> + +<dl> +<dd> +If set, this attribute indicates the color model of Palette that should +be used with the Image. This attribute is of type H5T_C_S1, with +size 3, 4, or 5. The value is one of the color models described in +the Palette specification in <a href="#sect2.2">section 2.2 below</a>. +This attribute may be used only for IMAGE_SUBCLASS="IMAGE_TRUECOLOR" or +"IMAGE_INDEXED".</dd> +</dl> + +<dt> +Attribute name="<b>IMAGE_GAMMACORRECTION</b>"</dt> + +<dl> +<dd> +If set, this attribute gives the Gamma correction. The attribute +is type H5T_NATIVE_FLOAT. This attribute may be used only for IMAGE_SUBCLASS="IMAGE_TRUECOLOR" +or "IMAGE_INDEXED".</dd> +</dl> +Attribute name="<b>IMAGE_VERSION</b>" (Required) +<dl> +<dd> +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 number +is "1.2".</dd> + +<br> +<p> +<br> +<br> +<center><table BORDER=2 BGCOLOR="#FFFFFF" > +<caption><b>Table 1. Attributes of an Image 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>5</td> + +<td>"IMAGE"</td> +</tr> + +<tr> +<td>PALETTE</td> + +<td>O</td> + +<td>Array Object References</td> + +<td></td> + +<td><references to Palette datasets><sup>1</sup></td> +</tr> + +<tr> +<td>IMAGE_SUBCLASS</td> + +<td>O<sup>2</sup></td> + +<td>String</td> + +<td>15, +<br>12, +<br>15, +<br>13</td> + +<td> +<dt> +"IMAGE_GRAYSCALE",</dt> + +<dt> +"IMAGE_BITMAP",</dt> + +<dt> +"IMAGE_TRUECOLOR",</dt> + +<dt> +"IMAGE_INDEXED"</dt> +</td> +</tr> + +<tr> +<td>INTERLACE_MODE</td> + +<td>O<sup>3,6</sup></td> + +<td>String</td> + +<td>15</td> + +<td>The layout of components if more than one component per pixel.</td> +</tr> + +<tr> +<td>DISPLAY_ORIGIN</td> + +<td>O</td> + +<td>String</td> + +<td>2</td> + +<td>If set, indicates the intended location of the pixel (0,0).</td> +</tr> + +<tr> +<td>IMAGE_WHITE_IS_ZERO</td> + +<td>O<sup>3,4</sup></td> + +<td>Unsigned Integer</td> + +<td></td> + +<td>0 = false, 1 = true</td> +</tr> + +<tr> +<td>IMAGE_MINMAXRANGE</td> + +<td>O<sup>3,5</sup></td> + +<td>Array [2] <same datatype as data values></td> + +<td></td> + +<td>The (<minimum>, <maximum>) value of the data.</td> +</tr> + +<tr> +<td>IMAGE_BACKGROUNDINDEX</td> + +<td>O<sup>3</sup></td> + +<td>Unsigned Integer</td> + +<td></td> + +<td>The index of the background color.</td> +</tr> + +<tr> +<td>IMAGE_TRANSPARENCY</td> + +<td>O<sup>3,5</sup></td> + +<td>Unsigned Integer</td> + +<td></td> + +<td>The index of the transparent color.</td> +</tr> + +<tr> +<td>IMAGE_ASPECTRATIO</td> + +<td>O<sup>3,4</sup></td> + +<td>Unsigned Integer</td> + +<td></td> + +<td>The aspect ratio.</td> +</tr> + +<tr> +<td>IMAGE_COLORMODEL</td> + +<td>O<sup>3,6</sup></td> + +<td>String</td> + +<td>3, 4, or 5</td> + +<td>The color model, as defined below in the Palette specification for +attribute <b>PAL_COLORMODEL</b>.</td> +</tr> + +<tr> +<td>IMAGE_GAMMACORRECTION</td> + +<td>O<sup>3,6</sup></td> + +<td>Float</td> + +<td></td> + +<td>The gamma correction.</td> +</tr> + +<tr> +<td>IMAGE_VERSION</td> + +<td>R</td> + +<td>String</td> + +<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> |