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authorJörg Frings-Fürst <debian@jff-webhosting.net>2014-09-01 13:56:46 +0200
committerJörg Frings-Fürst <debian@jff-webhosting.net>2014-09-01 13:56:46 +0200
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+<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
+<html lang="en">
+<head>
+ <title>Using The TIFF Library</title>
+ <meta http-equiv="content-type" content="text/html; charset=ISO-8859-1">
+ <meta http-equiv="content-language" content="en">
+ <style type="text/css">
+ <!--
+ th {text-align: left; vertical-align: top; font-style: italic; font-weight: normal}
+ -->
+ </style>
+</head>
+<body lang="en" text="#000000" bgcolor="#ffffff" link="#0000ff" alink="#0000ff" vlink="#0000ff">
+ <table border="0" cellspacing="0" cellpadding="0">
+ <tr>
+ <td style="padding-left: 1em; padding-right: 1em"><img src="images/cat.gif" width="113" height="146" alt=""></td>
+ <td>
+ <h1>Using The TIFF Library</h1>
+ <p>
+ <tt>libtiff</tt> is a set of C functions (a library) that support
+ the manipulation of TIFF image files.
+ The library requires an ANSI C compilation environment for building
+ and presumes an ANSI C environment for use.
+ </p>
+ </td>
+ </tr>
+ </table>
+ <br>
+ <p>
+ <tt>libtiff</tt>
+ provides interfaces to image data at several layers of abstraction (and cost).
+ At the highest level image data can be read into an 8-bit/sample,
+ ABGR pixel raster format without regard for the underlying data organization,
+ colorspace, or compression scheme. Below this high-level interface
+ the library provides scanline-, strip-, and tile-oriented interfaces that
+ return data decompressed but otherwise untransformed. These interfaces
+ require that the application first identify the organization of stored
+ data and select either a strip-based or tile-based API for manipulating
+ data. At the lowest level the library
+ provides access to the raw uncompressed strips or tiles,
+ returning the data exactly as it appears in the file.
+ </p>
+ <p>
+ The material presented in this chapter is a basic introduction
+ to the capabilities of the library; it is not an attempt to describe
+ everything a developer needs to know about the library or about TIFF.
+ Detailed information on the interfaces to the library are given in
+ the <a href="http://www.remotesensing.org/libtiff/man/index.html">UNIX
+ manual pages</a> that accompany this software.
+ </p>
+ <p>
+ Michael Still has also written a useful introduction to libtiff for the
+ IBM DeveloperWorks site available at
+ <a href="http://www.ibm.com/developerworks/linux/library/l-libtiff">http://www.ibm.com/developerworks/linux/library/l-libtiff</a>.
+ </p>
+ <p>
+ The following sections are found in this chapter:
+ </p>
+ <ul>
+ <li><a href="#version">How to tell which version you have</a></li>
+ <li><a href="#typedefs">Library Datatypes</a></li>
+ <li><a href="#mman">Memory Management</a></li>
+ <li><a href="#errors">Error Handling</a></li>
+ <li><a href="#fio">Basic File Handling</a></li>
+ <li><a href="#dirs">TIFF Directories</a></li>
+ <li><a href="#tags">TIFF Tags</a></li>
+ <li><a href="#compression">TIFF Compression Schemes</a></li>
+ <li><a href="#byteorder">Byte Order</a></li>
+ <li><a href="#dataplacement">Data Placement</a></li>
+ <li><a href="#tiffrgbaimage">TIFFRGBAImage Support</a></li>
+ <li><a href="#scanlines">Scanline-based Image I/O</a></li>
+ <li><a href="#strips">Strip-oriented Image I/O</a></li>
+ <li><a href="#tiles">Tile-oriented Image I/O</a></li>
+ <li><a href="#other">Other Stuff</a></li>
+ </ul>
+ <hr>
+ <h2 id="version">How to tell which version you have</h2>
+ <p>
+ The software version can be found by looking at the file named
+ <tt>VERSION</tt>
+ that is located at the top of the source tree; the precise alpha number
+ is given in the file <tt>dist/tiff.alpha</tt>.
+ If you have need to refer to this
+ specific software, you should identify it as:
+ </p>
+ <p style="margin-left: 40px">
+ <tt>TIFF &lt;<i>version</i>&gt; &lt;<i>alpha</i>&gt;</tt>
+ </p>
+ <p>
+ where <tt>&lt;<i>version</i>&gt;</tt> is whatever you get from
+ <tt>"cat VERSION"</tt> and <tt>&lt;<i>alpha</i>&gt;</tt> is
+ what you get from <tt>"cat dist/tiff.alpha"</tt>.
+ </p>
+ <p>
+ Within an application that uses <tt>libtiff</tt> the <tt>TIFFGetVersion</tt>
+ routine will return a pointer to a string that contains software version
+ information.
+ The library include file <tt>&lt;tiffio.h&gt;</tt> contains a C pre-processor
+ define <tt>TIFFLIB_VERSION</tt> that can be used to check library
+ version compatiblity at compile time.
+ </p>
+ <hr>
+ <h2 id="typedefs">Library Datatypes</h2>
+ <p>
+ <tt>libtiff</tt> defines a portable programming interface through the
+ use of a set of C type definitions.
+ These definitions, defined in in the files <b>tiff.h</b> and
+ <b>tiffio.h</b>,
+ isolate the <tt>libtiff</tt> API from the characteristics
+ of the underlying machine.
+ To insure portable code and correct operation, applications that use
+ <tt>libtiff</tt> should use the typedefs and follow the function
+ prototypes for the library API.
+ </p>
+ <hr>
+ <h2 id="mman">Memory Management</h2>
+ <p>
+ <tt>libtiff</tt> uses a machine-specific set of routines for managing
+ dynamically allocated memory.
+ <tt>_TIFFmalloc</tt>, <tt>_TIFFrealloc</tt>, and <tt>_TIFFfree</tt>
+ mimic the normal ANSI C routines.
+ Any dynamically allocated memory that is to be passed into the library
+ should be allocated using these interfaces in order to insure pointer
+ compatibility on machines with a segmented architecture.
+ (On 32-bit UNIX systems these routines just call the normal <tt>malloc</tt>,
+ <tt>realloc</tt>, and <tt>free</tt> routines in the C library.)
+ </p>
+ <p>
+ To deal with segmented pointer issues <tt>libtiff</tt> also provides
+ <tt>_TIFFmemcpy</tt>, <tt>_TIFFmemset</tt>, and <tt>_TIFFmemmove</tt>
+ routines that mimic the equivalent ANSI C routines, but that are
+ intended for use with memory allocated through <tt>_TIFFmalloc</tt>
+ and <tt>_TIFFrealloc</tt>.
+ </p>
+ <hr>
+ <h2 id="errors">Error Handling</h2>
+ <p>
+ <tt>libtiff</tt> handles most errors by returning an invalid/erroneous
+ value when returning from a function call.
+ Various diagnostic messages may also be generated by the library.
+ All error messages are directed to a single global error handler
+ routine that can be specified with a call to <tt>TIFFSetErrorHandler</tt>.
+ Likewise warning messages are directed to a single handler routine
+ that can be specified with a call to <tt>TIFFSetWarningHandler</tt>
+ </p>
+ <hr>
+ <h2 id="fio">Basic File Handling</h2>
+ <p>
+ The library is modeled after the normal UNIX stdio library.
+ For example, to read from an existing TIFF image the
+ file must first be opened:
+ </p>
+ <p style="margin-left: 40px">
+ <tt>#include "tiffio.h"<br>
+ main()<br>
+ {<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;TIFF* tif = TIFFOpen("foo.tif", "r");<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;... do stuff ...<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;TIFFClose(tif);<br>
+ }</tt>
+ </p>
+ <p>
+ The handle returned by <tt>TIFFOpen</tt> is <i>opaque</i>, that is
+ the application is not permitted to know about its contents.
+ All subsequent library calls for this file must pass the handle
+ as an argument.
+ </p>
+ <p>
+ To create or overwrite a TIFF image the file is also opened, but with
+ a <tt>"w"</tt> argument:
+ <p>
+ <p style="margin-left: 40px">
+ <tt>#include "tiffio.h"<br>
+ main()<br>
+ {<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;TIFF* tif = TIFFOpen("foo.tif", "w");<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;... do stuff ...<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;TIFFClose(tif);<br>
+ }</tt>
+ </p>
+ <p>
+ If the file already exists it is first truncated to zero length.
+ </p>
+ <table>
+ <tr>
+ <td valign=top><img src="images/warning.gif" width="40" height="40" alt=""></td>
+ <td><i>Note that unlike the stdio library TIFF image files may not be
+ opened for both reading and writing;
+ there is no support for altering the contents of a TIFF file.</i></td>
+ </tr>
+ </table>
+ <p>
+ <tt>libtiff</tt> buffers much information associated with writing a
+ valid TIFF image. Consequently, when writing a TIFF image it is necessary
+ to always call <tt>TIFFClose</tt> or <tt>TIFFFlush</tt> to flush any
+ buffered information to a file. Note that if you call <tt>TIFFClose</tt>
+ you do not need to call <tt>TIFFFlush</tt>.
+ </p>
+ <hr>
+ <h2 id="dirs">TIFF Directories</h2>
+ <p>
+ TIFF supports the storage of multiple images in a single file.
+ Each image has an associated data structure termed a <i>directory</i>
+ that houses all the information about the format and content of the
+ image data.
+ Images in a file are usually related but they do not need to be; it
+ is perfectly alright to store a color image together with a black and
+ white image.
+ Note however that while images may be related their directories are
+ not.
+ That is, each directory stands on its own; their is no need to read
+ an unrelated directory in order to properly interpret the contents
+ of an image.
+ </p>
+ <p>
+ <tt>libtiff</tt> provides several routines for reading and writing
+ directories. In normal use there is no need to explicitly
+ read or write a directory: the library automatically reads the first
+ directory in a file when opened for reading, and directory information
+ to be written is automatically accumulated and written when writing
+ (assuming <tt>TIFFClose</tt> or <tt>TIFFFlush</tt> are called).
+ </p>
+ <p>
+ For a file open for reading the <tt>TIFFSetDirectory</tt> routine can
+ be used to select an arbitrary directory; directories are referenced by
+ number with the numbering starting at 0. Otherwise the
+ <tt>TIFFReadDirectory</tt> and <tt>TIFFWriteDirectory</tt> routines can
+ be used for sequential access to directories.
+ For example, to count the number of directories in a file the following
+ code might be used:
+ </p>
+ <p style="margin-left: 40px">
+ <tt>#include "tiffio.h"<br>
+ main(int argc, char* argv[])<br>
+ {<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;TIFF* tif = TIFFOpen(argv[1], "r");<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;if (tif) {<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;int dircount = 0;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;do {<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;dircount++;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;} while (TIFFReadDirectory(tif));<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;printf("%d directories in %s\n", dircount, argv[1]);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;TIFFClose(tif);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;}<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;exit(0);<br>
+ }</tt>
+ </p>
+ <p>
+ Finally, note that there are several routines for querying the
+ directory status of an open file:
+ <tt>TIFFCurrentDirectory</tt> returns the index of the current
+ directory and
+ <tt>TIFFLastDirectory</tt> returns an indication of whether the
+ current directory is the last directory in a file.
+ There is also a routine, <tt>TIFFPrintDirectory</tt>, that can
+ be called to print a formatted description of the contents of
+ the current directory; consult the manual page for complete details.
+ </p>
+ <hr>
+ <h2 id="tags">TIFF Tags</h2>
+ <p>
+ Image-related information such as the image width and height, number
+ of samples, orientation, colorimetric information, etc.
+ are stored in each image
+ directory in <i>fields</i> or <i>tags</i>.
+ Tags are identified by a number that is usually a value registered
+ with the Aldus (now Adobe) Corporation.
+ Beware however that some vendors write
+ TIFF images with tags that are unregistered; in this case interpreting
+ their contents is usually a waste of time.
+ </p>
+ <p>
+ <tt>libtiff</tt> reads the contents of a directory all at once
+ and converts the on-disk information to an appropriate in-memory
+ form. While the TIFF specification permits an arbitrary set of
+ tags to be defined and used in a file, the library only understands
+ a limited set of tags.
+ Any unknown tags that are encountered in a file are ignored.
+ There is a mechanism to extend the set of tags the library handles
+ without modifying the library itself;
+ this is described <a href="addingtags.html">elsewhere</a>.
+ </p>
+ <p>
+ <tt>libtiff</tt> provides two interfaces for getting and setting tag
+ values: <tt>TIFFGetField</tt> and <tt>TIFFSetField</tt>.
+ These routines use a variable argument list-style interface to pass
+ parameters of different type through a single function interface.
+ The <i>get interface</i> takes one or more pointers to memory locations
+ where the tag values are to be returned and also returns one or
+ zero according to whether the requested tag is defined in the directory.
+ The <i>set interface</i> takes the tag values either by-reference or
+ by-value.
+ The TIFF specification defines
+ <i>default values</i> for some tags.
+ To get the value of a tag, or its default value if it is undefined,
+ the <tt>TIFFGetFieldDefaulted</tt> interface may be used.
+ </p>
+ <p>
+ The manual pages for the tag get and set routines specifiy the exact data types
+ and calling conventions required for each tag supported by the library.
+ </p>
+ <hr>
+ <h2 id="compression">TIFF Compression Schemes</h2>
+ <p>
+ <tt>libtiff</tt> includes support for a wide variety of
+ data compression schemes.
+ In normal operation a compression scheme is automatically used when
+ the TIFF <tt>Compression</tt> tag is set, either by opening a file
+ for reading, or by setting the tag when writing.
+ </p>
+ <p>
+ Compression schemes are implemented by software modules termed <i>codecs</i>
+ that implement decoder and encoder routines that hook into the
+ core library i/o support.
+ Codecs other than those bundled with the library can be registered
+ for use with the <tt>TIFFRegisterCODEC</tt> routine.
+ This interface can also be used to override the core-library
+ implementation for a compression scheme.
+ </p>
+ <hr>
+ <h2 id="byteorder">Byte Order</h2>
+ <p>
+ The TIFF specification says, and has always said, that
+ <em>a correct TIFF
+ reader must handle images in big-endian and little-endian byte order</em>.
+ <tt>libtiff</tt> conforms in this respect.
+ Consequently there is no means to force a specific
+ byte order for the data written to a TIFF image file (data is
+ written in the native order of the host CPU unless appending to
+ an existing file, in which case it is written in the byte order
+ specified in the file).
+ </p>
+ <hr>
+ <h2 id="dataplacement">Data Placement</h2>
+ <p>
+ The TIFF specification requires that all information except an
+ 8-byte header can be placed anywhere in a file.
+ In particular, it is perfectly legitimate for directory information
+ to be written after the image data itself.
+ Consequently TIFF is inherently not suitable for passing through a
+ stream-oriented mechanism such as UNIX pipes.
+ Software that require that data be organized in a file in a particular
+ order (e.g. directory information before image data) does not
+ correctly support TIFF.
+ <tt>libtiff</tt> provides no mechanism for controlling the placement
+ of data in a file; image data is typically written before directory
+ information.
+ </p>
+ <hr>
+ <h2 id="tiffrgbaimage">TIFFRGBAImage Support</h2>
+ <p>
+ <tt>libtiff</tt> provides a high-level interface for reading image
+ data from a TIFF file. This interface handles the details of
+ data organization and format for a wide variety of TIFF files;
+ at least the large majority of those files that one would normally
+ encounter. Image data is, by default, returned as ABGR
+ pixels packed into 32-bit words (8 bits per sample). Rectangular
+ rasters can be read or data can be intercepted at an intermediate
+ level and packed into memory in a format more suitable to the
+ application.
+ The library handles all the details of the format of data stored on
+ disk and, in most cases, if any colorspace conversions are required:
+ bilevel to RGB, greyscale to RGB, CMYK to RGB, YCbCr to RGB, 16-bit
+ samples to 8-bit samples, associated/unassociated alpha, etc.
+ </p>
+ <p>
+ There are two ways to read image data using this interface. If
+ all the data is to be stored in memory and manipulated at once,
+ then the routine <tt>TIFFReadRGBAImage</tt> can be used:
+ </p>
+ <p>
+ <p style="margin-left: 40px">
+ <tt>#include "tiffio.h"<br>
+ main(int argc, char* argv[])<br>
+ {<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;TIFF* tif = TIFFOpen(argv[1], "r");<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;if (tif) {<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;uint32 w, h;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;size_t npixels;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;uint32* raster;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;TIFFGetField(tif, TIFFTAG_IMAGEWIDTH, &amp;w);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;TIFFGetField(tif, TIFFTAG_IMAGELENGTH, &amp;h);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;npixels = w * h;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;raster = (uint32*) _TIFFmalloc(npixels * sizeof (uint32));<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if (raster != NULL) {<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if (TIFFReadRGBAImage(tif, w, h, raster, 0)) {<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;...process raster data...<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;_TIFFfree(raster);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;TIFFClose(tif);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;}<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;exit(0);<br>
+ }</tt>
+ </p>
+ <p>
+ Note above that <tt>_TIFFmalloc</tt> is used to allocate memory for
+ the raster passed to <tt>TIFFReadRGBAImage</tt>; this is important
+ to insure the ``appropriate type of memory'' is passed on machines
+ with segmented architectures.
+ </p>
+ <p>
+ Alternatively, <tt>TIFFReadRGBAImage</tt> can be replaced with a
+ more low-level interface that permits an application to have more
+ control over this reading procedure. The equivalent to the above
+ is:
+ </p>
+ <p style="margin-left: 40px">
+ <tt>#include "tiffio.h"<br>
+ main(int argc, char* argv[])<br>
+ {<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;TIFF* tif = TIFFOpen(argv[1], "r");<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;if (tif) {<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;TIFFRGBAImage img;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;char emsg[1024];<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if (TIFFRGBAImageBegin(&amp;img, tif, 0, emsg)) {<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;size_t npixels;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;uint32* raster;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;npixels = img.width * img.height;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;raster = (uint32*) _TIFFmalloc(npixels * sizeof (uint32));<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if (raster != NULL) {<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if (TIFFRGBAImageGet(&amp;img, raster, img.width, img.height)) {<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;...process raster data...<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;_TIFFfree(raster);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;TIFFRGBAImageEnd(&amp;img);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;} else<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;TIFFError(argv[1], emsg);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;TIFFClose(tif);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;}<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;exit(0);<br>
+ }</tt>
+ </p>
+ <p>
+ However this usage does not take advantage of the more fine-grained
+ control that's possible. That is, by using this interface it is
+ possible to:
+ </p>
+ <ul>
+ <li>repeatedly fetch (and manipulate) an image without opening
+ and closing the file</li>
+ <li>interpose a method for packing raster pixel data according to
+ application-specific needs (or write the data at all)</li>
+ <li>interpose methods that handle TIFF formats that are not already
+ handled by the core library</li>
+ </ul>
+ <p>
+ The first item means that, for example, image viewers that want to
+ handle multiple files can cache decoding information in order to
+ speedup the work required to display a TIFF image.
+ </p>
+ <p>
+ The second item is the main reason for this interface. By interposing
+ a "put method" (the routine that is called to pack pixel data in
+ the raster) it is possible share the core logic that understands how
+ to deal with TIFF while packing the resultant pixels in a format that
+ is optimized for the application. This alternate format might be very
+ different than the 8-bit per sample ABGR format the library writes by
+ default. For example, if the application is going to display the image
+ on an 8-bit colormap display the put routine might take the data and
+ convert it on-the-fly to the best colormap indices for display.
+ </p>
+ <p>
+ The last item permits an application to extend the library
+ without modifying the core code.
+ By overriding the code provided an application might add support
+ for some esoteric flavor of TIFF that it needs, or it might
+ substitute a packing routine that is able to do optimizations
+ using application/environment-specific information.
+ </p>
+ <p>
+ The TIFF image viewer found in <b>tools/sgigt.c</b> is an example
+ of an application that makes use of the <tt>TIFFRGBAImage</tt>
+ support.
+ </p>
+ <hr>
+ <h2 id="scanlines">Scanline-based Image I/O</h2>
+ <p>
+ The simplest interface provided by <tt>libtiff</tt> is a
+ scanline-oriented interface that can be used to read TIFF
+ images that have their image data organized in strips
+ (trying to use this interface to read data written in tiles
+ will produce errors.)
+ A scanline is a one pixel high row of image data whose width
+ is the width of the image.
+ Data is returned packed if the image data is stored with samples
+ packed together, or as arrays of separate samples if the data
+ is stored with samples separated.
+ The major limitation of the scanline-oriented interface, other
+ than the need to first identify an existing file as having a
+ suitable organization, is that random access to individual
+ scanlines can only be provided when data is not stored in a
+ compressed format, or when the number of rows in a strip
+ of image data is set to one (<tt>RowsPerStrip</tt> is one).
+ </p>
+ <p>
+ Two routines are provided for scanline-based i/o:
+ <tt>TIFFReadScanline</tt>
+ and
+ <tt>TIFFWriteScanline</tt>.
+ For example, to read the contents of a file that
+ is assumed to be organized in strips, the following might be used:
+ </p>
+ <p style="margin-left: 40px">
+ <tt>#include "tiffio.h"<br>
+ main()<br>
+ {<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;TIFF* tif = TIFFOpen("myfile.tif", "r");<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;if (tif) {<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;uint32 imagelength;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;tdata_t buf;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;uint32 row;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;TIFFGetField(tif, TIFFTAG_IMAGELENGTH, &amp;imagelength);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;buf = _TIFFmalloc(TIFFScanlineSize(tif));<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;for (row = 0; row &lt; imagelength; row++)<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;tiffreadscanline(tif, buf, row);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;_tifffree(buf);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;tiffclose(tif);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;}<br>
+ }</tt>
+ </p>
+ <p>
+ <tt>TIFFScanlineSize</tt> returns the number of bytes in
+ a decoded scanline, as returned by <tt>TIFFReadScanline</tt>.
+ Note however that if the file had been create with samples
+ written in separate planes, then the above code would only
+ read data that contained the first sample of each pixel;
+ to handle either case one might use the following instead:
+ </p>
+ <p style="margin-left: 40px">
+ <tt>#include "tiffio.h"<br>
+ main()<br>
+ {<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;TIFF* tif = TIFFOpen("myfile.tif", "r");<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;if (tif) {<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;uint32 imagelength;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;tdata_t buf;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;uint32 row;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;TIFFGetField(tif, TIFFTAG_IMAGELENGTH, &amp;imagelength);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;TIFFGetField(tif, TIFFTAG_PLANARCONFIG, &amp;config);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;buf = _TIFFmalloc(TIFFScanlineSize(tif));<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if (config == PLANARCONFIG_CONTIG) {<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;for (row = 0; row &lt; imagelength; row++)<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;tiffreadscanline(tif, buf, row);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;} else if (config == planarconfig_separate) {<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;uint16 s, nsamples;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;tiffgetfield(tif, tifftag_samplesperpixel, &amp;nsamples);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;for (s = 0; s &lt; nsamples; s++)<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;for (row = 0; row &lt; imagelength; row++)<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;tiffreadscanline(tif, buf, row, s);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;_tifffree(buf);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;tiffclose(tif);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;}<br>
+ }</tt>
+ </p>
+ <p>
+ Beware however that if the following code were used instead to
+ read data in the case <tt>PLANARCONFIG_SEPARATE</tt>,...
+ </p>
+ <p style="margin-left: 40px">
+ <tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;for (row = 0; row &lt; imagelength; row++)<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;for (s = 0; s &lt; nsamples; s++)<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;tiffreadscanline(tif, buf, row, s);</tt>
+ </p>
+ <p>
+ ...then problems would arise if <tt>RowsPerStrip</tt> was not one
+ because the order in which scanlines are requested would require
+ random access to data within strips (something that is not supported
+ by the library when strips are compressed).
+ </p>
+ <hr>
+ <h2 id="strips">Strip-oriented Image I/O</h2>
+ <p>
+ The strip-oriented interfaces provided by the library provide
+ access to entire strips of data. Unlike the scanline-oriented
+ calls, data can be read or written compressed or uncompressed.
+ Accessing data at a strip (or tile) level is often desirable
+ because there are no complications with regard to random access
+ to data within strips.
+ </p>
+ <p>
+ A simple example of reading an image by strips is:
+ </p>
+ <p style="margin-left: 40px">
+ <tt>#include "tiffio.h"<br>
+ main()<br>
+ {<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;TIFF* tif = TIFFOpen("myfile.tif", "r");<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;if (tif) {<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;tdata_t buf;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;tstrip_t strip;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;buf = _TIFFmalloc(TIFFStripSize(tif));<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;for (strip = 0; strip &lt; tiffnumberofstrips(tif); strip++)<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;tiffreadencodedstrip(tif, strip, buf, (tsize_t) -1);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;_tifffree(buf);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;tiffclose(tif);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;}<br>
+ }</tt>
+ </p>
+ <p>
+ Notice how a strip size of <tt>-1</tt> is used; <tt>TIFFReadEncodedStrip</tt>
+ will calculate the appropriate size in this case.
+ </p>
+ <p>
+ The above code reads strips in the order in which the
+ data is physically stored in the file. If multiple samples
+ are present and data is stored with <tt>PLANARCONFIG_SEPARATE</tt>
+ then all the strips of data holding the first sample will be
+ read, followed by strips for the second sample, etc.
+ </p>
+ <p>
+ Finally, note that the last strip of data in an image may have fewer
+ rows in it than specified by the <tt>RowsPerStrip</tt> tag. A
+ reader should not assume that each decoded strip contains a full
+ set of rows in it.
+ </p>
+ <p>
+ The following is an example of how to read raw strips of data from
+ a file:
+ </p>
+ <p style="margin-left: 40px">
+ <tt>#include "tiffio.h"<br>
+ main()<br>
+ {<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;TIFF* tif = TIFFOpen("myfile.tif", "r");<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;if (tif) {<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;tdata_t buf;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;tstrip_t strip;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;uint32* bc;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;uint32 stripsize;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;TIFFGetField(tif, TIFFTAG_STRIPBYTECOUNTS, &amp;bc);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;stripsize = bc[0];<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;buf = _TIFFmalloc(stripsize);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;for (strip = 0; strip &lt; tiffnumberofstrips(tif); strip++) {<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if (bc[strip] &gt; stripsize) {<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;buf = _TIFFrealloc(buf, bc[strip]);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;stripsize = bc[strip];<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;TIFFReadRawStrip(tif, strip, buf, bc[strip]);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;_TIFFfree(buf);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;TIFFClose(tif);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;}<br>
+ }</tt>
+ </p>
+ <p>
+ As above the strips are read in the order in which they are
+ physically stored in the file; this may be different from the
+ logical ordering expected by an application.
+ </p>
+ <hr>
+ <h2 id="tiles">Tile-oriented Image I/O</h2>
+ <p>
+ Tiles of data may be read and written in a manner similar to strips.
+ With this interface, an image is
+ broken up into a set of rectangular areas that may have dimensions
+ less than the image width and height. All the tiles
+ in an image have the same size, and the tile width and length must each
+ be a multiple of 16 pixels. Tiles are ordered left-to-right and
+ top-to-bottom in an image. As for scanlines, samples can be packed
+ contiguously or separately. When separated, all the tiles for a sample
+ are colocated in the file. That is, all the tiles for sample 0 appear
+ before the tiles for sample 1, etc.
+ </p>
+ <p>
+ Tiles and strips may also be extended in a z dimension to form
+ volumes. Data volumes are organized as "slices". That is, all the
+ data for a slice is colocated. Volumes whose data is organized in
+ tiles can also have a tile depth so that data can be organized in
+ cubes.
+ </p>
+ <p>
+ There are actually two interfaces for tiles.
+ One interface is similar to scanlines, to read a tiled image,
+ code of the following sort might be used:
+ </p>
+ <p style="margin-left: 40px">
+ <tt>main()<br>
+ {<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;TIFF* tif = TIFFOpen("myfile.tif", "r");<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;if (tif) {<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;uint32 imageWidth, imageLength;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;uint32 tileWidth, tileLength;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;uint32 x, y;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;tdata_t buf;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;TIFFGetField(tif, TIFFTAG_IMAGEWIDTH, &amp;imageWidth);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;TIFFGetField(tif, TIFFTAG_IMAGELENGTH, &amp;imageLength);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;TIFFGetField(tif, TIFFTAG_TILEWIDTH, &amp;tileWidth);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;TIFFGetField(tif, TIFFTAG_TILELENGTH, &amp;tileLength);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;buf = _TIFFmalloc(TIFFTileSize(tif));<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;for (y = 0; y &lt; imagelength; y += tilelength)<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;for (x = 0; x &lt; imagewidth; x += tilewidth)<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;tiffreadtile(tif, buf, x, y, 0);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;_tifffree(buf);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;tiffclose(tif);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;}<br>
+ }</tt>
+ </p>
+ <p>
+ (once again, we assume samples are packed contiguously.)
+ </p>
+ <p>
+ Alternatively a direct interface to the low-level data is provided
+ a la strips. Tiles can be read with
+ <tt>TIFFReadEncodedTile</tt> or <tt>TIFFReadRawTile</tt>,
+ and written with <tt>TIFFWriteEncodedTile</tt> or
+ <tt>TIFFWriteRawTile</tt>. For example, to read all the tiles in an image:
+ </p>
+ <p style="margin-left: 40px">
+ <tt>#include "tiffio.h"<br>
+ main()<br>
+ {<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;TIFF* tif = TIFFOpen("myfile.tif", "r");<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;if (tif) {<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;tdata_t buf;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;ttile_t tile;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;buf = _TIFFmalloc(TIFFTileSize(tif));<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;for (tile = 0; tile &lt; tiffnumberoftiles(tif); tile++)<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;tiffreadencodedtile(tif, tile, buf, (tsize_t) -1);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;_tifffree(buf);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;tiffclose(tif);<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;}<br>
+ }</tt>
+ </p>
+ <hr>
+ <h2 id="other">Other Stuff</h2>
+ <p>
+ Some other stuff will almost certainly go here...
+ </p>
+ <hr>
+ <p>
+ Last updated: $Date: 2005/12/28 06:53:18 $
+ </p>
+</body>
+</html>