You cannot select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
exiv2/doc/getting-started.html

95 lines
4.4 KiB
HTML

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>Exiv2 - Exif and Iptc metadata manipulation library and tools</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<link href="html/doxygen.css" rel="stylesheet" type="text/css">
</head>
<body>
<h1>Getting started</h1>
<h2><a href="html/namespaces.html">Namespaces</a></h2>
<p>The <a href="html/index.html">Exiv2 library</a> is made up of all
elements defined in the <a href="html/namespaceExiv2.html">Exiv2
namespace</a>. The Action and Util namespaces are only used by the
Exiv2 command line utility. Thus, to learn about the library, concentrate on
the members of the Exiv2 namespace.</p>
<h2><a href="html/classes.html">Classes</a></h2>
<p><a class="el" href="html/classExiv2_1_1ExifData.html">Exiv2::ExifData</a>
and <a class="el" href="html/classExiv2_1_1IptcData.html">Exiv2::IptcData</a>
are the top-level classes of the Exiv2 library. They hold a container
of Exif and Iptc metadata, respectively, and define related methods to
access and manipulate the metadata. The containers hold objects derived from
<a class="el" href="html/classExiv2_1_1Metadatum.html">Exiv2::Metadatum</a>.
Interface class Exiv2::Metadatum defines methods to access the
information of one Exif tag or Iptc dataset. It models the tag data as
a key and value pair.
The abstract base class
<a class="el" href="html/classExiv2_1_1Key.html">Exiv2::Key</a> defines the
interface for a key. Concrete keys implement Exif and Iptc keys.
The abstract base class
<a class="el" href="html/classExiv2_1_1Value.html">Exiv2::Value</a> defines
the interface to access tag information, from which concrete values are
derived. The actual value used in a metadatum depends on the type of
the Exif tag or Iptc dataset. It is usually determined when the Exif metadata
is read from an image. It is also possible to manually create a Value and
together with a key add it to an ExifData or IptcData container.</p>
<h2><a href="html/examples.html">Examples</a></h2>
<p>There are several simple examples that demonstrate the basic use of Exiv2
functionality: <a href="html/exifprint_8cpp-example.html">Exifprint</a>
shows how the Exif data of an image can be read and written to the screen.
<a href="html/iptcprint_8cpp-example.html">Iptcprint</a> is a similar
example to print Iptc data.
<a href="html/addmoddel_8cpp-example.html">Addmoddel</a> shows how to
add, modify and delete Exif metadata.
<a href="html/exifcomment_8cpp-example.html">Exifcomment</a> shows how to
set the exif comment of an image.
For more real-world code have a look at the implementation of the
different actions of the Exiv2 utility (actions.cpp).</p>
<h2><a href="makernote.html">Makernotes</a></h2>
<p>Exif Makernote data can be accessed through ExifData in the same
way as the standard Exif tags. In other words, for each entry of a
known Makernote, there is a corresponding Metadatum in the ExifData
container. The abstract base class
<a class="el" href="html/classExiv2_1_1MakerNote.html">Exiv2::MakerNote</a> defines
the Makernote interface. Subclass
<a class="el" href="html/classExiv2_1_1IfdMakerNote.html">Exiv2::IfdMakerNote</a>
models makernotes encoded in IFD format.
<a href="html/classExiv2_1_1MakerNote.html#_details">Implementing a new
IFD makernote</a> is straightforward. Implementing a new makernote that is not
encoded in IFD format however, is more difficult. Please
<a href="mailto:ahuggel@gmx.net"> contact me</a> if you have such a
makernote specification and would like assistance adding it to Exiv2.</p>
<h2><a class="anchor">IFD (Image File Directory)</a></h2>
<p><a class="el" href="html/classExiv2_1_1Ifd.html">Exiv2::Ifd</a> is a generic
low-level class that models an image file directory as defined by TIFF
and used in the Exif standard. Exiv2::Ifd could be used to implement
read only as well as read/write access to Exif (or TIFF) data without
the overhead (and convenience) of Exiv2::ExifData.</p>
<h2><a class="anchor">Components</a></h2>
<p>The picture below shows the components that make up the Exiv2
library and how they depend on each other. Component names are the
same as the basenames of their source files. Each component has its
own header and source files.</p>
<center>
<h3><a class="anchor">Exiv2 Components Diagram</a></h3>
<p><img src="exiv2.gif" width="475" height="447" alt="Exiv2 components diagram"></p>
</center>
<p>&nbsp;</p>
</body>
</html>